Search

The influence of dimensions of cheese slices on the melting property of cheese was investigated with a computer vision method using image analysis techniques. Tests were carried out with Cheddar and Mozzarella cheeses. The results show that the meltability of cheese increased linearly when the side length of square cheese slices increased from 25 to 70 mm. The meltability of cheese also increased proportionally as the thickness of cheese slices was increased from 2 to 4 mm. The influences of the area/thickness of cheese slices on cheese meltability were similar for both the Cheddar and Mozzarella cheeses. The opposite changes may occur for different meltability indices when the initial area of cheese slices varied. [Copyright &y& Elsevier]

A series of numerical simulations using a computational fluid dynamics (CFD) code was carried out to predict core temperature and weight loss profiles of cooked meat during the vacuum cooling process. The CFD model allows the simultaneous prediction of unsteady heat and mass transfer, such as temperature distribution, weight loss and water content of the meats at vacuum pressure. The numerical simulation was verified by experiment with cooling cooked meat with cylindrical shape within an experimental vacuum cooler. Further calculations were performed to investigate the effects of anisotropy and thermal shrinkage of the food, vapour and water transport within the food, radiation on the surface, and the pressure history of the cooling process. [Copyright &y& Elsevier]

Computational fluid dynamics (cfd) is a simulation tool, which uses powerful computer and applied mathematics to model fluid flow situations for the prediction of heat, mass and momentum transfer and optimal design in industrial processes. It is only in recent years that cfd has been applied in the food processing industry. This paper reviews the application of cfd in food processing industries including drying, sterilisation, refrigeration and mixing. The advantages of using cfd are discussed and the future of cfd applications is also outlined. [Copyright &y& Elsevier]

The thermophysical properties of a cooked beef product cooled using vacuum cooling (VC) and three other cooling treatments including air blast (AB), water immersion (WI) and slow air (SA) were measured. Thermal conductivity, specific heat capacity, thermal diffusivity, porosity, true density and apparent density together with proximates were evaluated in fully cooked and cooled samples. The thermal conductivity showed a good correlation with water content and porosity particularly in vacuum-cooled samples. Thermal conductivity decreased with decreasing apparent density in samples. Loss of moisture and development of porosity during VC had the most significant effects on the thermophysical properties of the samples cooled. [Copyright &y& Elsevier]

The performance of slow air, air blast and water immersion cooling methods in the cooked meat industry was evaluated by a validated finite element model. The cooked meat joints in commercial and controlled geometries were cooled by these three traditional cooling methods under different operating conditions. Simulations showed that it is difficult for traditional cooling methods to cool the large commercial cooked meat joints because the poor thermal conductivity of meat controls the cooling rate. It takes about 8.5, 6.5 and 3.5 h for air blast cooling with an air velocity of 3 m/s and an air temperature of 0°C to reduce the cooked meat joints in a typical ellipsoid shape with the weights of 8, 5 and 2 kg from the core temperature of 74–10°C, respectively. For water immersion cooling with water velocity of 0.15 m/s and water temperature of 0°C, the cooling times can be reduced to 7, 5 and 2.8 h, respectively. A rapid cooling can be achieved by controlling the shortest dimension. For cooling a cooked meat joint with the weight more than 5 kg by air blast cooling to meet the cooling requirements specified in cook-chill guidelines, the infinite slab shape with the shortest dimension of 5 cm and an infinite cylinder with the diameter of 10 cm was chosen. For water immersion cooling, the shortest dimension of the brick-shaped meat joints could be increased to near 10 cm. [Copyright &y& Elsevier]

The three-dimensional transient heat transfer of roasted meat during air blast cooling process was modelled by the finite element method for evaluating the cooling performance. Moisture loss rate was considered in the model to account for the weight loss during air blast cooling. The model includes the variations in physical properties of the roasted meat and in operating conditions during the air blast cooling process. A user-friendly computer program developed in visual C++ by the authors was used to solve the model. The model was validated by comparing the numerical solutions with the experimental results. The comparison showed that the maximum deviation between the predicted and experimental core temperatures was within 2.4°C. The deviation between the predicted and experimental total weight loss was 2.5%. The model and software can also be used to analyse other thermal processing procedures of foods with some modifications. [Copyright &y& Elsevier]

A computer vision system was used to evaluate the melting property of cheese. The method is suitable for both cheddar and mozzarella cheese. The effect of cooking time (0–20 min) and temperature (70–200°C) on the melting degree and melting rate of cheddar and mozzarella cheese was investigated and the melting property of both cheeses were compared. Both cheddar and mozzarella cheese melted rapidly at the initial stage of cooking and melting slowed down in about 3–4 min. Maximum melting degree and melting rate occurred at about 130–160°C. Extended cooking and cooking at high temperature may cause reduced melting. Cheddar cheese melted more rapidly and considerably than mozzarella cheese at all cooking temperatures. [Copyright &y& Elsevier]

Background : Freezing is one of the most common methods for preserving meat and meat products. Ice crystals are a key factor in the quality of frozen meat and meat products. Common freezing methods used in the food industry such as air-blast freezing and liquid immersion freezing could form large and irregular ice crystals in the extracellular region of the frozen meat and meat products and cause tissue damages, leading to quality and nutrient losses upon thawing. Therefore, it is important to enhance the quality of frozen meat and meat products by controlling the formation and distribution of ice crystals during freezing. Scope and approach : This review presents the key mechanisms in enhancing the physical and chemical quality attributes of frozen meat and meat products and the techniques available for realizing these enhancements. The mechanisms discussed include acceleration of freezing rates, formation of small and evenly distributed ice crystals and generation of intracellular ice crystals. The effects of these mechanisms on enhancing microstructure, moisture, texture feature, and colour, and pH values, protein, and lipid are analyzed in detail. In addition, their effects on microbiological safety are also discussed. Key findings and conclusions : The improvements in the quality of frozen meats can be achieved through the control of the formation and distribution of ice crystals in different approaches. Among the techniques available for realizing these improvements, high-pressure freezing, ultrasound-assisted immersion freezing, and oscillating magnetic field-assisted freezing can form small and intracellular ice crystals mainly by accelerating the freezing rate, while static electric field-assisted freezing, radiofrequency assisted freezing, and microwave-assisted freezing have the ability to form small ice crystals by controlling the motion of water molecules in electric or magnetic fields. Furthermore, anti-freezing proteins can combine with water molecules to inhibit the growth of ice crystals, thereby forming small ice crystals. However, many challenges remain in the research and exploitation of these novel technologies, and further studies can focus on establishing models for describing freezing processes assisted by the above novel freezing technologies, developing techniques for the proper control of ice crystal nucleation, growth, and distribution, translating laboratory results of the above novel freezing techniques into industrial applications. • We present key mechanisms in enhancing quality attributes of frozen meat products. • We discuss innovative techniques available for realizing these enhancements. • We analyse methods for controlling ice crystal formation and distribution in meats. • We highlight challenges in further technological developments for the industry. [ABSTRACT FROM AUTHOR]

Efficient identification of pathogenic bacteria is greatly concerned with microbial food safety and foodborne diseases diagnosis. Surface-enhanced Raman scattering (SERS) tags are among the cutting-edge tools for bioanalysis, but facing troubles in either SERS sensitivity, durability, interfering signals, or universal recognition agents for target bacteria. This work proposed a multivariate scheme enabled by polyphenolic chemistry for the green synthesis, facile stabilization (functionalization), protective encapsulation, and bio-affinitive design of metal-phenolic networks (MPNs)-encapsulated silver SERS nanotags (AgNPs@4-mercaptobenzonitrile@MPNs). With remarkable SERS properties, shelf stability, and bacterial affinity, AgNPs@4-mercaptobenzonitrile@MPNs tags enabled rapid, reproducible, and interference-free SERS detection of two representative foodborne pathogens (i.e., E. coli O157: H7 and S. aureus) in the assistance of an aptamer-labelled magnetic probe, reaching good sensitivity and selectivity. Moreover, this SERS biosensor worked well in real food samples, manifesting the potential of polyphenolic chemistry in the customization of bio-affinitive SERS nanotags for food safety detection. [Display omitted] • Polyphenolic chemistry enabled from-synthesis-to-bioaffinity scheme of SERS tags. • Metal-phenolic networks acted as bioaffinity elements for bacterial recognition. • Polyphenolic SERS tags could be reliable detection probe for bacteria quantitation. • Polyphenolic SERS biosensor could detect foodborne bacteria down to 102 CFU/mL. • The SERS biosensor could work in milk and beef samples. [ABSTRACT FROM AUTHOR]

The development of flexible and robust plasmonic substrates has become a hot research topic in simplifying and extending the application of surface-enhanced Raman scattering (SERS) technique for real-world analysis. In this work, a facile method to fabricate an Au@Ag nanoparticle array sandwiched between the adhesive acrylic polymer tape and polyethene terephthalate (PET) film (T/Au@Ag/PET) as a high-performance SERS chip was reported for nondestructive detection of thiram on fruit peels. For this SERS chip, the ordered Au@Ag nanoparticle array formed by the self-assembly method was closely-packed, which generated high‐density sub‐3‐nm gaps and could produce high reproducible and sensitive SERS enhancement effects. The measurement of crystal violet with the limit of detection of 7.24 × 10−10 M was realized by targeting Raman shift at 1177 cm−1. Moreover, the excellent flexible feature of acrylic polymer tape enabled the substrate to withstand a tensile strain value of 20% for three cycles without significantly losing its SERS activity. By covering with a PET film, the SERS chip could maintain 87% SERS activity after storage for 60 days in the air environment, and could well withstand the influence of harsh conditions such as high temperature and ultrasound treatments. As a proof of the concept, the SERS tape was directly used to detect thiram on apple, tomato, and cucumber peels via a simple sampling-and-detection procedure, and the detection limit of 5 ng/cm2 was achieved. The T/Au@Ag/PET SERS chip should hold a promising candidate for food safety analysis in the future. Image 1 • The Au@Ag nanoparticle array was sandwiched between acrylic polymer tape and PET film. • Highly dense hotspots of the array ensured good performance for SERS detection. • The SERS chip showed excellent flexibility and storage stability. • The SERS chip was used for nondestructive detection of thiram in fruit peels. [ABSTRACT FROM AUTHOR]

The effect of plasma functionalized water (PW) pretreatment and influencing factors including treatment time and voltage were investigated on the drying kinetics, nutrition and sensory properties of tomato slices during infrared-accelerated pulsed vacuum drying (IR-PVD). Results revealed that PW pretreatment caused disruptions in tomato cellular structure that were greater with increasing treatment time and voltage, due to strong acidification and etching from reactive species in PW. These disruptions accelerated the removal of moisture during IR-PVD to shorten drying time by 25%, and improve visual appearance, rehydration, porosity, phenols and flavonoids, soluble solids, lycopene, ascorbic acid, but reduced chewiness, gumminess and hardness properties. Overall, the findings revealed the propitious potentials of PW and indicated the significant effects of PW influencing factors for accelerating drying characteristics and increasing the functional and nutrition properties of tomato slices during IR-PVD, providing a theoretical basis for developing novel energy-saving drying approaches. • Plasma water provides a viable alternative for pretreating tomato slices prior to IR-PVD. • Increasing treatment time and voltage led to increased porosity in the microstructure. • Plasma water accelerated moisture transfer and shortened drying time. • Highest vitamin C retention achieved at the peak of treatment time and voltage. • Future studies should emphasis on optimization for large-scale applications. [ABSTRACT FROM AUTHOR]

• DPA-CuNCs with AIE properties were suitable to prepare FSA as sensing indicator. • FSA achieved the qualitative and quantitative analysis of NH 3 , TMA, and DMA gases. • SqueezeNet had the best ability for meat freshness monitoring based on FSA images. • ONNX method could deploy SqueezeNet into various production and daily environments. • UMAP and Grad-CAM improved the interpretability of SqueezeNet in model decision. A fluorescent sensor array (FSA) combined with deep learning (DL) techniques was developed for meat freshness real-time monitoring from development to deployment. The array was made up of copper metal nanoclusters (CuNCs) and fluorescent dyes, having a good ability in the quantitative and qualitative detection of ammonia, dimethylamine, and trimethylamine gases with a low limit of detection (as low as 131.56 ppb) in range of 5 ∼ 1000 ppm and visually monitoring the freshness of various meats stored at 4 °C. Moreover, SqueezeNet was applied to automatically identify the fresh level of meat based on FSA images with high accuracy (98.17 %) and further deployed in various production environments such as personal computers, mobile devices, and websites by using open neural network exchange (ONNX) technique. The entire meat freshness recognition process only takes 5 ∼ 7 s. Furthermore, gradient-weighted class activation mapping (Grad-CAM) and uniform manifold approximation and projection (UMAP) explanatory algorithms were used to improve the interpretability and transparency of SqueezeNet. Thus, this study shows a new idea for FSA assisted with DL in meat freshness intelligent monitoring from development to deployment. [ABSTRACT FROM AUTHOR]

Photothermal sensing, due to its high resolution and spatial controllability, has gained significant attention in optical imaging for applications such as disease treatment and diagnosis, environmental monitoring, etc. It has effectively overcome the drawbacks of traditional sensors, such as susceptibility to interference, high cost, lack of portability, and strong dependency on operational procedures. Photothermal conversion-based light-responsive temperature change sensors have been proven to break limitations, serving as an alternative strategy for more potential applications, particularly in the detection of hazardous substances in food. In the current review, the principles of temperature generation in photothermal materials and the corresponding representative materials are inducted and the modulation of temperature signals in sensors and the response-dependent principle for rapid detection are discussed. The practical applications of photothermal sensors in food hazard detection and the outlook on the challenges faced are also presented in the current review. Various doped and modified photothermal materials have been shown to enable quantitative detection of food hazards through different temperature signal modulation mechanisms as well as relying on non-specific, molecular biological and immunological responses. It is hoped that the review can provide researchers with reference sources for further developments of more effective and sensitive photothermal sensors for food safety assurance for the food industry. • Photothermal sensors can break the limits of conventional detection. • Material shape change and human intervention dominate thermoregulation. • Detection of reactions including oxidation, molecular biology and immunology. • Photothermal sensing suitable for quantitative detection of food hazards. [ABSTRACT FROM AUTHOR]

Atmospheric pressure dielectric barrier discharge cold plasma (CP) is an effective method for inactivating microorganism contamination. However, improving CP inactivation efficiency as affected by CP reactor parameters still remains unstudied. In this study, the effects of discharge voltage, dielectric material and dielectric thickness of CP reactor on inactivation performance were investigated, and their influence mechanisms on plasma discharge were discussed. Results indicated that efficiency was improved using the reactor parameters of a high discharge voltage (17 kV) with a centre frequency (10 kHz) and a high dielectric constant (ceramic) with a small dielectric thickness (1 mm), resulting in higher electron number density and electric field strength, producing more reactive substances for enhancing microorganism inactivation. Under the above conditions, CP treatment for 4 min inactivated 99.6% of Salmonella typhimurium and 96.1% of Listeria monocytogenes. It is hoped that this work could guide the design of commercial CP systems. • A novel evaluation method was established to assess the performance of reactors. • The plasma characteristics were diagnosed by electrical and optical methods. • The effects of CP reactor parameters on inactivation performance were investigated. • The possible influence mechanism of CP reactor parameters was proposed. [ABSTRACT FROM AUTHOR]

• A durian-shaped core-shell SERS substrate of Fe 3 O 4 @Au@Ag@Au was synthesized. • The SERS substrate had high SERS performance and good magnetic. • A "flow magnetic detection method" was proposed for non-destructive detection. • The DFAAA could be completely collected from the food surface with the new method. • The substrate could quantitatively detect the pesticide residues on food surface. A new type of durian-shaped Fe 3 O 4 @Au@Ag@Au (DFAAA) multilayer core-shell composite was prepared as an efficient surface-enhanced Raman scattering (SERS) substrate. The optimization process and SERS enhancement mechanism of the substrate were further explained with finite-difference time-domain simulation. The dense and uniform spiny array on the DFAAA surface had abundant "hot spots", greatly improving sensitivity, uniformity and reproducibility, with a Raman enhancement factor of 3.01 × 107 and storage-life of 30 d. A "flow magnetic detection method" was proposed to realize rapid and flexible detection of pesticide residues on the surface of different foods including fish and apple. The limit of detection of malachite green and thiram on the fish and apple surfaces were 0.13 and 0.18 ng/cm2, respectively. With its high SERS performance and good magnetic, the DFAAA possessed great application prospects as a facile SERS substrate for rapid and non-destructive detection of trace pesticide residues on foods. [ABSTRACT FROM AUTHOR]

A universal surface-enhanced Raman scattering (SERS) substrate with tuneable plasmonic behaviour and long-term stability was synthesized and characterized, and the substrate was applied in the sensitive detection of fungicide malachite green (MG) in fish fillets. Temperature-responsive poly (N-isopropyl acrylamide) (pNIPAM) template and anisotropic Au nanorods (NRs) were synthesized to prepare pNIPAM @ Au NRs nano-hybrids with dynamically optical and SERS properties and high stability. Results showed that excitation wavelength-dependent SERS efficiency could be tailored by temperature-induced swelling and collapse of the nano-hybrids, thus anticipated optical and SERS properties of the composites could be obtained. Furthermore, the SERS performance, uniformity, long-term stability analysis, and MG in fish evaluation showed that the detection of MG in fish tissues was realized with a limit of detection of 1.58 × 10−9 M (0.73 ng/g), and the pNIPAM @ Au NRs composites could serve as effective SERS substrates allowing trace level detection of contaminants for the food industry. Image 1 • PNIPAM @ Au NRs with tunable plasmon behaviour and high stability was synthesized. • Excitation wavelength-dependent SERS efficiency can be tailored by temperature. • The synergistic versus competitive mechanisms of SERS and SERRS were first proposed. • Three analytes (MG, SC, SS) exist in food safety issues were detected in trace level. • The LOD of MG in fish tissues was 0.73 ng/g with recoveries 80.7–115.6% obtained. [ABSTRACT FROM AUTHOR]

• Multifunctional Fe 3 O 4 @Au nanoflowers have been successfully synthesized. • Au-4MBA@Ag nanospheres with stable and strong SERS signal was prepared as SERS tag. • High-performance SERS aptasensor was successfully developed by aptamer recognition. • The ultralow detection limit of AFB1 was estimated to be 0.40 pg·mL−1. Aflatoxin B1 (AFB1) as the most toxic mycotoxin in contaminated food can greatly threaten human health, and sensitive and selective detection of AFB1 is thus highly desired. An ultrasensitive surface-enhanced Raman spectroscopy (SERS) aptasensor was developed for AFB1 detection in peanut oil samples. SH-cDNA modified Fe 3 O 4 @Au nanoflowers acted as capture probes, SH-Apt modified Au@Ag nanospheres and commercial Cy3-Apt were used as reporter probes. Strong SERS signals of reporter probes were produced due to the recognition of AFB1 aptamer and its complementary strand (SH-cDNA). With the preferred binding of AFB1 aptamer to AFB1, reporter probes were released from capture probes, causing a linear decrease in SERS intensity. Therefore an ultralow detection limit of 0.40 pg·mL−1 in a wide linear range of 0.0001–100 ng·mL−1 was obtained and the sensibility of this SERS aptasensor was higher than that of the Cy3-Apt based SERS aptasensor. In addition, an excellent selectivity in interfering toxins and satisfactory recoveries of 96.6–115% in peanut oil samples were obtained, proving this aptasensor is a promising analytical tool in AFB1 detection. [ABSTRACT FROM AUTHOR]

Mixed pesticides are usually applied to agricultural products to enhance agricultural production. However, their presence in the environment and food poses serious health risks to humans. Therefore, rapid and reliable detection methods for mixed pesticides residues are in need to minimize potential health hazards. Herein, a nondestructive and sensitive strategy was developed to determine thiram and thiabendazole (TBZ) mixture on fruit surface using surface-enhanced Raman spectroscopy (SERS) technology coupled with interfacial self-assembly gold nanorods (Au NRs) array substrates together with self-modelling mixture analysis (SMA) method. Firstly, a large area high-density Au NRs array was fabricated by organic-aqueous interfacial self-assembly to serve as a sensitive SERS substrate for simultaneously screening of thiram and TBZ on the fruit surface. Then, an SMA method was employed to identify and separate the Raman spectrum for each pesticide from the Raman spectra of the pesticides mixture on the contaminated fruit surface. Results showed that using SERS technique with the SMA method, qualitative and quantitative analyses of a single component from the spectra of the mixture were simultaneously realized, and the resolved pure spectrum of each pesticide was presented. The limits of detection (LOD) of pesticides on the surface of apple, tomato and pear were 0.041, 0.029 and 0.047 ng/cm2 for thiram, and 0.79, 0.76 and 0.80 ng/cm2 for TBZ, respectively. It was anticipated that the proposed SERS detection approach combined with SMA methods should pave the way for detecting multi-analytes in practical applications for agriculture and food safety inspection. Image 1 • High density Au NRs array substrates was fabricated by interfacial self-assembly. • A swab-extract method was developed for the pesticides recovery on fruit surface. • Thiram & TBZ mixture on fruit surface were simultaneous detected using SERS method. • The resolved pure spectrum for each pesticide using SMA method was presented. • Qualitative and quantitative of single pesticide from mixed spectra were realized. [ABSTRACT FROM AUTHOR]

• Pork samples were processed with 5 methods under 3 conditions. • Hyperspectral imaging (HSI) was applied to evaluate processed pork samples. • Monounsaturated and Polyunsaturated fatty acids in samples were predicted by HSI. • LS-SVM models were better than PLSR models. Freezing, heating, and pickling are common processes for pork meats. Unsaturated fatty acids including monounsaturated fatty acids and polyunsaturated fatty acids are indispensable nutrition beneficial to human's health and growth. However, Unsaturated fatty acids are affected by processing methods. Hyperspectral imaging is a novel technique widely used for food quality and safety evaluation. In the current study, the contents of monounsaturated and polyunsaturated fatty acids were assessed by Hyperspectral imaging. Optimal wavelengths were selected by the regression coefficients curves of partial least squares regression models. The least-squares support vector machine models established achieved a better coefficient of determination in the Monte Carlo validation set than the partial least squares regression models developed and the R2 MV values for the least squares - support vector machine models based on selected optimal wavelengths were higher than 0.81. Finally, colour maps of the contents of monounsaturated and polyunsaturated fatty acids were developed. [ABSTRACT FROM AUTHOR]

• SERS can simultaneously and rapidly screen contaminants in milk. • Bimetallic core shelled nanoparticles were employed as Raman active substrates. • Thiram was first time reported in milk samples. • The proposed method can detect thiram and DCD up to 0.21 and 20 ppm. • The results can be achieved within 34 min. Existing methods for contaminants detection in liquid milk are complex, requires chemicals and time-consuming experimental procedure. In this study, SERS based on bimetallic core shelled nanoparticles was employed for simultaneous and fast detection of thiram and dicyandiamide (DCD) in the milk. Spectra ranging from 400 to 1700 cm−1 were selected to examine thiram (0.5, 1, 2, 5 and 10 ppm) and DCD (20, 40, 80,160 and 320 ppm), by employing 28 nm gold cores and silver-shell thickness of 8 nm. A strong peak at 1379 cm−1 was ascribed to thiram with LOD of 0.21 ppm and R2 of 0.9896, whereas a band at 929 cm−1 was associated with DCD, delivering LOD of 14.88 ppm and R2 of 0.9956. The proposed method could achieve results within 34 min and this ecofriendly method can be further employed for simultaneous and rapid screening of other accidental contaminants in milk. [ABSTRACT FROM AUTHOR]

• A 2D Au@Ag nanodot array was constructed at the biphase system for SERS analysis. • The 2D Au@Ag nanodot array can generate vigorous electromagnetic fields. • The assay is capable of measuring fungicides in fruit juices with low LOD values. • SERS provides a rapid and sensitive way of detecting contaminants in foods. The design of a novel and reliable plasmonic platform for detecting multiple chemical contaminants in the complex matrix is an exciting topic in the food industry. Herein, a high-performance surface-enhanced Raman scattering (SERS) two-dimensional (2D) nanodot array was designed through liquid-liquid interfacial self-assembly of the core-shell nanoparticles (Au@Ag NPs) and exploited for assessment of dual-fungicides in pear, apple, and orange juices. The 2D Au@Ag nanodot array delivered good uniformity and reproducibility with the substrate-to-substrate relative standard deviation values of 10.51%. This substrate could be used for detecting thiram and thiabendazole in aqueous solutions with the limit of detection of 0.0011 and 0.051 ppm, respectively. Furthermore, satisfactory recoveries ranging from 76–134% for the juices were obtained, demonstrating that the high-throughput 2D Au@Ag nanodot arrays are promising for their applications as sensitive SERS platforms for monitoring chemical contaminants in food products, especially in the beverage industry. [ABSTRACT FROM AUTHOR]

Tropomyosin (TM), a myofibrillar protein, is a major allergen in most crustaceans including king pawn (Litopenaeus vannamei). In this study, the structural modifications and allergenic response of TM in fresh king prawn as induced by cold argon plasma jet (CAPJ) were examined. The result showed that the level of α-helix structures declined as treatment time progressed, while the level of β-sheets and random coils increased. The free sulfhydryl groups decreased as CAPJ treatment progressed due to the formation of disulphide bonds while surface hydrophobicity increased until equilibrium values. In addition, after 15 min of plasma exposure, the maximum reduction recorded for IgE and IgG binding capacities were 17.6% and 26.87% respectively as revealed by ELISA test. These findings correlated with the occurrence of protein unfolding and denaturation, evident by complementary structural analyses conducted. The study indicates that non-thermal plasma maybe a promising tool for developing hypoallergenic food products. [ABSTRACT FROM AUTHOR]

The development of techniques and methods for rapidly and reliably detecting and analysing food quality and safety products is of significance for the food industry. Traditional machine learning algorithms based on handcrafted features normally have poor performance due to their limited representation capacity for complex food characteristics. Recently, the convolutional neural network (CNN) emerges as an effective and potential tool for feature extraction, which is considered the most popular architecture of deep learning and has been increasingly applied for the detection and analysis of complex food matrices. In the current review, the structure of CNN, the method of feature extraction based on 1-D, 2-D and 3-D CNN models, and multi-feature aggregation methods are introduced. Applications of CNN as a depth feature extractor for detecting and analyzing complex food matrices are discussed, including meat and aquatic products, cereals and cereal products, fruits and vegetables, and others. In addition, data sources, model architecture and overall performance of CNN with other existing methods are compared, and trends of future studies on applying CNN for food detection and analysis are also highlighted. CNN combined with nondestructive detection techniques and computer vision system show great potential for effectively and efficiently detecting and analysing complex food matrices, and the features based on CNN show better performance and outperform the features handcrafted or those extracted by machine learning algorithms. Although there still remains some challenges in using CNN, it is expected that CNN models will be deployed on mobile devices for real-time detection and analysis of food matrices in future. • The principle and architectures of convolutional neural network are presented. • Feature extraction methods based on convolutional neural network are investigated. • Recent applications of convolutional neural network in food are summarized. • Challenges and future work of convolutional neural network are discussed. [ABSTRACT FROM AUTHOR]

Fruits and vegetables are an essential class of food with enormous nutritional and commercial gains. With the surge in interest for nutraceuticals, the demand for high-quality fruits and vegetables have gained traction in recent times. In a bid to extend shelf life and retain quality to meet demand, drying of fruits and vegetables has been accompanied by pretreatments. Conventional pretreatments have shown to improve the drying process in terms of drying kinetics and final product quality. However, for further improving and enhancing the drying process, novel nonthermal and thermal pretreatments have been investigated. This paper reviews some novel nonthermal and thermal pretreatment techniques with a focus on their efficacies to improve the drying process in terms of amelioration of drying kinetics and enhancement of the functional and nutritional quality of the dried product. Details of the pretreatment techniques including cold plasma, pulsed electric field, edible coating, ultrasonication, high humidity hot air impingement blanching, infrared blanching, and microwave blanching are discussed, and their possible application drawbacks and prospects in future developments are also presented. Key Findings and Conclusions: The development and application of novel pretreatment techniques can not only shorten drying time, increase drying rate, improve moisture distribution, and lower energy consumption but can also further enhance the functional and nutritional quality attributes of the dried products better than conventionally pretreated and untreated samples. Additionally, combinations of these technologies and adequate modelling approaches for optimizing the pretreatment conditions can further boost their effectiveness in enhancing the drying process. • Pretreatments can enhance drying performance and improve product quality. • Nonthermal techniques can facilitate permeability by tissue modification. • Novel thermal techniques can accelerate moisture evaporation and transfer. • Future work can focus on hurdle technology and process modelling. [ABSTRACT FROM AUTHOR]

Freezing and refrigeration play an essential role in the quality preservation of perishable food products, however, the undesired ice or frost accretion on freezing facility surfaces results in high-energy consumption with adverse economical and environmental effects. Recently, biomimetic surfaces with superwettability have been proven to delay icing and frosting on cold substrates or to de-ice and de-frost easily, with the potential of supplementing or even replacing conventional de-icing or defrosting technologies. Applying this technology to the freezing and cold chain of food can significantly reduce energy consumption and enhance the freezing efficiency for the food industry. In this review, the anti-icing mechanism of biomimetic surfaces with superwettability including water repellency, icing or frosting retarding and ultralow ice adhesion strength are presented. Recent research efforts made to improve mechanical stability, practicality and the safety of superhydrophobic surfaces (SHSS), as well as slippery liquid-infused porous surface (SLIPS), are discussed. The potential applications of bionic surfaces for food refrigeration industry are also highlighted, including the development of energy-saving heat exchanger and applications in frozen food production and preservation. SHSS show the capability to retard freezing and SLIPS possess excellent de-icing performance for ultralow ice adhesion. Since the bare nano-coating is easily worn out, the adhesive enhanced superhydrophobic nano-coatings could endow the coating with robust and longlasting anti-icing capacity. The future trends of bionic anti-freezing materials development should mainly focus on non-toxicity, robust mechanical stability, economy and scalability. • We discuss the anti-icing mechanism of biomimetic non-wetting surfaces. • We present advances in developing robust and eco-friendly anti-icing materials. • We propose potential applications of bionic modified surfaces in the food industry. • Future efforts should be devoted to industrialize bionic anti-freezing materials. [ABSTRACT FROM AUTHOR]

Sensory analysis is the evaluation of the signals received through senses of sight, sound, taste, smell, and touch. The traditional methods for the analysis of sensory properties including trained sensory panel, colourimeters and texture analysers are invasive, laborious, and small-scale procedures. Hyperspectral imaging systems (HSI) has emerged as a less time-consuming and non-destructive method to determine the sensory properties of a diverse range of food products. This review provides a comprehensive overview of recent application developments since 2010 for identifying sensory properties including colour, defects, texture, flavour, freshness, and maturity in various food products by HSI. The Vis-NIR (400–1000 nm) hyperspectral imaging is most used for the assessment of sensory properties. Moreover, the commonly applied multivariate analysis in the sensory evaluation by HSI is linear regression algorithms (PLSR and MLR), but non-linear analysis achieves better performance for the prediction of sensory features. Regression models are applied for determining the texture, colour, flavour, and freshness of food products while classification models are used to detect the defects and maturity by which the most accurate results are obtained. Furthermore, the combination of algorithms and the integration of spectral and spatial information yield more accurate results in the assessment of sensory features. Although there are still some limitations to overcome for the improvement of the HSI system, studies on the application of HSI in the real-time monitoring of sensory properties have proved a great potential for industrial applications. • Vis-NIR (400–1000 nm) hyperspectral imaging is most used in sensory evaluation. • The most used chemometric is linear regression algorithms in sensory evaluation. • The most accurate results are obtained in the detection of bruise and maturity. • Regression models are applied to predict texture, color, flavour and freshness. • Classification models are used to detect the defect and maturity. [ABSTRACT FROM AUTHOR]

Mycotoxin contamination in agri-food products compromises human and animal health throughout the supply chains, thus the establishment of rapid and accurate methods for the detection of mycotoxins is essential for food safety assurance. Among the preferred spectral methods, surface-enhanced Raman scattering (SERS) has emerged as an attractive solution for detecting trace mycotoxins in complex food matrices due to its advantages of high sensitivity, rapidness and non-destructiveness. However, relevant developments in research in this field are scarcely reviewed. In the current review, the fundamentals of SERS and substrates for detecting mycotoxin in agri-foods are introduced, technical developments in the detection procedure including combined techniques, fingerprinting and SERS tagging and spectral optimizations such as using chemometrics are elaborated. Recent applications of SERS methods for trace level detection of mycotoxins in agri-food samples including cereal grains, fruits, dairy products, and wine are also highlighted, and limitations and future prospects for developing the SERS technology for detecting mycotoxin contamination are finally presented. SERS is a rapid and sensitive technique for detecting trace mycotoxins. However, the preparation of high-performance SERS substrates for on-site quantitative analysis of real food samples is still a challenging scientific problem. Future research should focus on designing reliable SERS substrates, establishing SERS fingerprint libraries of mycotoxins, and developing accurate chemometric methods, and choosing suitable combined techniques in order to achieve an early adoption of the SERS method as a practical tool for detecting mycotoxin contamination in the agri-food industry. • Mycotoxin contamination in foods is a considerable challenge. • SERS technique can detect AFs, OTs, ZEN, DON, FB and other mycotoxins in foods. • SERS detection of mycotoxins includes fingerprinting and SERS tagging methods. • The speed and sensitivity of the SERS technique will facilitate mycotoxin inspection. [ABSTRACT FROM AUTHOR]

Food safety issues leading to severe healthy, economic and even social problems and detection of food contaminants has been attracting remarkable attention in recent decades. Surface-enhanced Raman scattering (SERS) is one of the most promising techniques to enable detecting contaminants at trace levels. Besides, with the emergence of global resource shortages and environmental problems, there is a growing demand for environmentally friendly and renewable resources. As a sustainable and biodegradable raw material, cellulose has aroused great interest and stimulated researchers to develop cellulose-based SERS substrates with novel functions. The review focuses on the utilizing of cellulosic materials for the design and preparation of various SERS substrates, including cellulose-papers, cellulose fabrics (CFs) and membranes, cellulose nanofibrils (CNFs), bacterial cellulose (BC), nanocrystalline cellulose (NCC), and surface-modified cellulose. The applications, challenges and potential solutions of these cellulose-based substrates in food safety detection are also presented, proposed and evaluated. For the complexity and diversity of multitudinous food systems, multiple approaches have been successfully employed to manufacture cellulose-based SERS substrates. Various types of cellulose with diverse morphology and mechanical properties make them customizable and integratable with multiple technologies in certain realistic applications. The explorations of SERS detections displaying excellent performances especially for the complex system/surface analysis with the capability of extraction, swabbing, transferring and concentrating target molecules from complexing food systems. The widespread application and prominent performance demonstrating the huge potential for cellulose-based materials to realize commercially viable, sustainable, flexible and green substrates in the near future. • Cellulose material is an excellent choice for SERS substrate design and fabrication. • Cellulose-based substrate is customizable in certain food safety inspection. • Cellulose can extract, swab, transfer and concentrate analytes from complex media. • Cellulose-SERS tests display good performances in complex food systems and surface. • Cellulose-SERS can realize commercial viable, in-situ, flexible and green detection. [ABSTRACT FROM AUTHOR]

Aflatoxins are one of the maximal menaces to food safety and public health and can contaminate food during the entire process from field to table, which can then be digested by the consumer, causing irreversible negative impacts such as immunotoxic, carcinogenic, and mutagenic effects. Therefore, development of novel technology to decontaminate aflatoxins is obviously important for the food industry. Cold plasma (CP) is an emerging novel nonthermal technology with eco-friendliness, high-efficiency and low cost, which has recently been widely studied for inactivating microorganisms and mycotoxins. This review presents a brief overview of aflatoxins and cold plasma treatment (CPT) and provides detailed information on the blocking and degradation of aflatoxins by CPT and its potential mechanisms. Furthermore, the superiority of CPT in purifying aflatoxins is highlighted by comparison with conventional methods including physical, chemical and biological treatments. Finally, the limitations and challenges of CPT are also discussed. Recent studies show that CPT is an alternative technique to conventional methods for aflatoxins decontamination. However, the effective components and exact sites where CPT works are not completely clear, and the types of food researched are also few. Further researches should focus on breaking through these bottlenecks and provide a theoretical basis for the promotion of CPT applications. • Aflatoxins contamination is a vital challenge facing the food industry. • Cold plasma treatment (CPT) shows great feasibility of decontamination. • CPT has superiority in purifying aflatoxins compared with traditional methods. • The potential mechanism of aflatoxins decontamination is discussed. [ABSTRACT FROM AUTHOR]

• Effects of CP treatment on TM allergenicity were characterized by a mouse model. • The potential of CP to eliminate the TM allergenicity was verified. • The mechanism of intestine flora-involved allergy occurrence was revealed. • The possibility of CP regulating intestine flora to inhibit allergy was exhibited. In vivo biological regulations of the allergenicity of tropomyosin (TM) treated by cold plasma (CP) were investigated by in vivo mouse model. The sensitization models of Balb/c mice were successfully established. CP treatment reduced the allergic symptoms of mice and regulated the Th1/Th2 balance to prevent allergy by activating Treg cells, which was deduced by serum and cytokines analysis. For intestinal flora analysis, allergy occurrence was accompanied by the decreased species abundance and the increased species diversity of intestinal flora. The significant species composition difference between the TM group and the PBS group showed a possible connection between bacterial diversity and allergy. Furthermore, Firmicutes, Bacteroidetes, Parabacteroides, Alloprevotella, Bacteroides, and Lachnospiraceae could relate to allergy occurrence. Intestinal section analysis suggested that allergy occurrence was accompanied by the damaged intestinal structure, and CP treatment could relieve the damage caused by an allergy. [ABSTRACT FROM AUTHOR]

The concern about the protein shortage has increased in recent years. There is a need to research sustainable alternatives for animal proteins, which have negative effects on sustainability and the environment. Due to the growth environment and nutritional values, quinoa proteins are considered a sustainable and renewable alternative to animal proteins. However, they have poor performance in techno-functional properties. Therefore, it is important to modify them to improve their techno-functional properties. In this review, the methods used to change the techno-functional properties of quinoa proteins, including extraction techniques (conventional and non-conventional) and modification methods (physical, chemical, and biological), are described and updated. The structural and techno-functional properties of quinoa proteins and their changes after the treatment are also discussed. Extraction techniques and modification methods could induce structural and physicochemical changes in quinoa proteins, which result in the improvement of techno-functional properties, including solubility, emulsion properties, and gelling properties. Various extraction methods have their advantages and disadvantages. The selection of extraction methods can be based on applying quinoa proteins. Further investigation should focus on hybrid extraction techniques to improve the extraction efficiency and techno-functional properties of quinoa proteins. Furthermore, modification approaches can also enhance the techno-functional properties of quinoa proteins and make quinoa proteins more suitable for application in the emulsion and gel system. • The extraction techniques and modification methods of quinoa proteins are reviewed. • Various extraction techniques can induce yield and structural changes in quinoa proteins. • Modification methods can modify structure and techno-functional properties of quinoa proteins. [ABSTRACT FROM AUTHOR]

• Osmotic pre-treatment improves the MVD efficiency of beef slices. • Osmotic pre-treatment curbs color and volume change of MVD beef. • Both THz-TDS and NIR-HSI achieved great MC prediction during MVD. • CV shows more reliable color measurement than chromameter during MVD. • Different MC migration patterns were observed in different pre-treated beef. Both nonthermal pretreatment and nondestructive analysis are effective technologies in improving drying processes. This study evaluated the effects of different pretreatment methods on the quality of beef dehydrated by microwave vacuum drying (MVD) and compared the MVD process performance comprising real-time moisture content (MC), MC loss, colour content, and shrinkage rate using different optical sensing methods including terahertz time-domain spectroscopy (THz-TDS) and near-infrared hyperspectral imaging (NIR-HSI). Results indicated that osmotic pretreatment improved the drying rate of MVD beef with lower changes in colour and shrinkage rate. Both THz-TDS-based and NIR-HSI-based on-site direct scanning and in-situ in-direct sensing showed accurate prediction results, with best R2 p of 0.9646 and 0.9463 for MC and R2 p of 0.9817 and 0.9563 for MC loss prediction, respectively. NIR-HSI visualisation of MC results showed that ultrasound pretreatment curbed but osmotic pretreatment promoted nonuniform distribution during MVD. This research should guide improving the industrial MVD drying process. [ABSTRACT FROM AUTHOR]

Plants constitute the foundation of sustainable environmental systems and human health. However, the limitations of solar radiation and the increased challenges of plant cultivation pose a threat to the environment and human health. In the past years, artificial lighting sources have been a hot topic in many fields, especially in plant cultivation owing to their controlled nature of the conditions. However, traditional artificial lighting sources suffer from unstable light quality, high energy consumption, and a short lifespan, which hinders their widespread use in agricultural farming. In contrast, light conversion technologies offer unparalleled advantages such as high conversion efficiency, stronger light harvesting, good photostability, and superior biocompatibility. With the flourishing development of nanotechnology, nano light conversion agents have been demonstrated to be alternative tools to traditional artificial light sources. Therefore, light conversion agents-guided plant cultivation is a promising strategy in the development of sustainable systems. This review introduces the mechanism and classification of nano light conversion agents and summarises recent advances in the applications of light conversion agents for plant cultivation. The prospects and challenges of light conversion agents are also discussed in the current review. • Light conversion mechanisms and classification of plant cultivation were reviewed. • Applications of light converter platforms for plant cultivation were summarized. • Prospects and challenges in applying nano light conversion agents were presented. [ABSTRACT FROM AUTHOR]

Surface-enhanced Raman scattering (SERS) technique is widely used in the field of food detection due to its rapidity, non-destructiveness and high sensitivity. However, non-recyclable substrates are limited in their practical detection application owing to high-cost and environmental pollution. Therefore, it is crucial to design SERS substrates that are recyclable and highly sensitive. Semiconductors with photocatalytic degradation capabilities have become attractive materials for the detection of contaminated residues in complex food matrices due to their high photocatalytic efficiency and environmental friendliness. Nevertheless, relevant research advances in this field have not been reviewed. In this review, the basic principles of SERS and semiconductor photocatalysis are introduced. The various constituent structures of semiconductors used for SERS substracts are described, including pure semiconductors, semiconductor-Ag/Au hybrid structures, and semiconductor-transition metal/semiconductor heterostructures. Then, the application of recyclable substrates for SERS detection of pesticides, dyes, antibiotics, heavy metals and other contaminants in agri-food products is then elaborated. Finally, the limitations and prospects of recyclable SERS substrates are presented. Photocatalytic semiconductors are potential candidates for the preparation of highly sensitive and recoverable SERS substrates. However, the development of recyclable SERS substrates for real sample detection remains a challenging scientific problem. Future research should focus on preparing novel photocatalytic semiconductor heterojunctions, investigating substrate interface catalytic processes and exploring the effects of complex food substrates on substrate recycling performance to improve the versatility of substrates and make them practical tools for the detection of food contaminants in the agri-food industry. • Photocatalytic semiconductors can be used to prepare recyclable SERS substrates. • Different structures of semiconductor recyclable SERS substrates are summarised. • Semiconductor SERS substrates will facilitate the detection of food contaminants. • Developing recyclable SERS substrates remains a challenge. [ABSTRACT FROM AUTHOR]

Fresh fruits and vegetables have a short shelf life. Freezing offers a solution to their long-term preservation. However, transport phenomena during freezing of fruits and vegetables pose significant changes in microstructure, affecting quality stability, shelf-life extension, and market value. Therefore, information on the microstructure of frozen fruits and vegetables is very critical for process design and quality control. In this review, transport phenomena and their effect on the microstructure of frozen fruits and vegetables are considered at the cell level. The effect of cell structure, freezing rates, and heat and mass transfer characteristics on the texture of cellular tissues are presented. Emerging techniques for controlling ice crystal growth are also discussed. The quality of frozen fruits and vegetables is hinged on the microstructure stability, which is highly dependent on phase change processes and the size of ice crystals. The proportion and characteristics of cellular water, heat and mass transfer parameters, freezing rate and thermal property of cells are considered as the main drivers for moisture migration and ice crystal formation. To produce frozen fruits and vegetables with high quality, more insightful study and accurate understanding of transport phenomena in cellular space and their corresponding effects on the microstructure is necessary. It is hoped that this review should provide critical information on preserving the microstructure and quality of fruits and vegetables as affected by moisture migration for future studies. [ABSTRACT FROM AUTHOR]

The interfacial performance of protein and polysaccharide plays a vital role in the improvement of food quality. As an innovative technology in food processing, cold plasma has attracted much attention from researchers and has become an attractive tool for nonthermal food processing due to the abundant reactive species generated at low temperatures. In particular, cold plasma shows great potential in food component modification. However, some of the specific physical-chemical reactions between reactive species in plasma, and protein and polysaccharide still remain obscure, limiting the development of accurate modification. This review provides an overview of the effects that plasma makes on the interfacial performance of protein and polysaccharide in the emulsion. Aspects discussed include types of active species in cold plasma, detailed interaction between reactive species, and protein and polysaccharide, and changes of interfacial properties. In addition, the current review presents a summary of the modification of protein and polysaccharide resulting from cold plasma application. The reactive species produced by cold plasma improve the interfacial performance of protein and polysaccharide by changing their residue composition and stereostructure. In the process of modification, hydrophobic groups hidden in protein are exposed and hydrophilic groups are grafted onto the polysaccharide skeleton. Meanwhile, the structural looseness is changed due to the breakage and the formation of bonds. Although successful applications of cold plasma for protein and polysaccharide modification have been demonstrated, it is not enough to characterize the changes at the macro level, and more in-depth studies should be conducted in the future. To improve the interfacial performance of protein and polysaccharide, the mechanism of plasma regulatable modification should be explored, and the accuracy of modification should be enhanced. • Cold plasma affects the interfacial performance of protein and polysaccharide. • Pathways among reactive species of cold plasma were systematically analyzed. • The chemical interaction between cold plasma and stabilizers was discussed. • Future research trends were proposed. [ABSTRACT FROM AUTHOR]

Native starches have been modified by employing various methods for desired industrial applications over the last few decades. There have been intense interests to develop novel methods with advantages of high-efficiency, environment-friendly and easy operation for starch modification. Although there is more attention to the functional properties of modified starch for practical applications in the industry, structural changes are the basis of functional changes, hence understanding the structural alteration induced by processing techniques is a fundamental issue towards better utilization of starch and starch modification techniques. The current review mainly presents the effects of several efficient physical processing techniques on the changes in the starch multi-scale structure including molecular structure, crystallinity, lamellae structure, and morphology characteristic. Among these techniques, the influences of high hydrostatic pressure, cold plasma, and microwave treatments are emphasized, and research gaps to better develop these techniques for starch modifications are suggested. Physical processing techniques by means of pressure, heat, radiation or free radicals can affect amylose, amylopectin, and degree of their interactions in the crystalline and amorphous region, as well as the packing mode of the crystal structure, thereby resulting in various functional properties and extensive applications in starch industries. However, the exact mechanisms behind these modification techniques are inconclusive because there are many affecting factors mainly including processing parameters, starch origin, and environment. Exploring new research methods or improving modified equipment to reduce the influence of these interference factors should be a good inspiration to study physical modification. • Novel physical techniques applied in starch modification are reviewed. • Changes in starch structure and gelatinization properties are compared and discussed. • Problems and challenges to apply these physical techniques are presented. [ABSTRACT FROM AUTHOR]

Foods have been commercially frozen for over 140 years. While improper frozen storage often causes food quality loss, the frozen damage induced by ice crystal growth is a serious problem. Freezing point (FP) regulation that promotes and inhibits ice nucleation, and controls ice crystal growth and recrystallization, may alleviate this problem. Some naturally sourced biosubstances with eco-friendly, green, nontoxic and highly effective characteristics are verified to regulate FP, showing potential for application in foods and food-related areas. This review introduces three groups of FP-regulating biosubstances, including ice-nucleating proteins (INPs), anti-freezing proteins (AFPs) and natural deep eutectic solvents (NADES). Existing knowledge of these biosubstances and updated information concerning their mechanisms for regulating FP are summarized. In addition, current applications of these natural FP regulators in foods or in food-related areas are presented, involving food processing, packaging and transgenic foods. Future applications of these biosubstances in the food and food-related researches are briefly discussed. The effect of natural FP regulators in improving food quality is worthy of further investigation into more extensive food applications, especially for INPs and NADES. The current review indicates that natural FP regulating biosubstances reveal application potential in foods and food-related areas. Future studies should mainly focus on bio-based or bio-inspired anti-freezing, micro/none ice-based cold storage and energy conservation in the food and food-related researches. • Ice-nucleating proteins effectively elevate freezing points. • Anti-freezing proteins and natural deep eutectic solvents reduce freezing points. • Ice-binding proteins regulate freezing points through special function domains. • Natural freezing point regulators can be applied in the food industry. • This is an updated review on natural freezing point regulators in food area. [ABSTRACT FROM AUTHOR]

Microbial contamination is an increasing concern in the food industry. In order to understand the effect of microorganisms, the study of their characteristics and behavior in various platforms is of prime importance. Over the years, time-consuming and labor-intensive, culture-based enumeration techniques have become obsolete for real-time applications, and increasing concerns on foodborne outbreaks necessitate rapid, on-site and sensitive methods for the detection of microorganisms in food matrices. In the current review, a brief discussion about biomarkers in microorganisms and bio-recognition ligands commonly used for detection assay are presented. The molecular interaction between biomarkers and ligands is critically evaluated and recent developments in bio-recognition based detection techniques for analyzing microorganism activity in complex food matrices are reviewed. The microbial activity in food can be detected by analyzing the specific biomarkers of microorganisms such as nucleic acids, proteins, antigens, and metabolic products. Recent bio-recognition ligands in detection techniques such as biosensors, lateral flow assay, and microfluidic devices can improve the selectivity in detecting cells from complex food matrices. The emerging bio-recognition based methods bridge the gap between culture-dependent enumeration and molecular methods, and they could be employed in the industry to ensure food safety. However, the development of a validation protocol for all the emerging methods is necessary to assess their efficiency in real samples. • Foodborne outbreaks necessitate rapid detection of microbial activity in food. • Biomarkers and bio-recognition ligands employed for detection are discussed. • Emerging bio-recognition based biosensors to ensure food safety are given. • Point-of-care use of lateral flow and microfluidic assay are briefly presented. [ABSTRACT FROM AUTHOR]

Stability of food is a great challenge that encompasses the interaction among the constituents, processing conditions and thermal history. The frozen storage of food sometimes incurs possible harmful effect due to the formation of large ice crystal and destruction of the cell structure. Glass transition state is a second-order transition of matter where a system reaches a thermodynamically non-equilibrium state due to the immobility of molecules, and it is a universal phenomenon observed when liquid goes to supercooled vitreous state because of extensive cooling or change in the composition. The cryostabilisation or storage at glassy conditions has been studied widely as it can prevent the quality degradation due to freezing. The review provides an overview of the theories and assumptions related to the concept of the glass transition and the response of different food components such as moisture, carbohydrate, protein, and lipid at the glassy state. Influences of processing conditions including moisture removal, freezing rate, annealing time on the relaxation process or the glass transition are also elaborated. In addition, the effects of novel freezing techniques such as ultrasound assisted, high pressure assisted, electric and magnetic field assisted freezing are also discussed in the current review. The glass transition is highly dependent on the presence of moisture and carbohydrate molecules for its great affinity to make hydrogen bond and increase viscosity. The fat and protein glass transitions take place at very low temperatures, at which commercial frozen storage is not considered feasible. Conventional freeze drying and dehydrofreezing require removal of water, which increases the glass transition temperature. Storage at or below the glass transition temperature is desired to increase stability and prevent any quality deterioration. Novel freezing processes such as high pressure, ultrasound, electric and magnetic assisted freezing incur changes in microstructure and metastable glassy states. The current review provides valuable information for designing products with optimized processing techniques and conditions. • Glass transitions for various food components are discussed. • Effects of novel freezing technologies on glass transition are elaborated. • Glass transitions have high impacts on stability and other food quality parameters. • Glass transitions are highly dependent on constituents and freezing conditions. [ABSTRACT FROM AUTHOR]

Fresh food are perishable, and freezing is a popular way of maintaining the quality and safety of foods. However, ice crystals formed during freezing may result in the breakage of cell structure, leading to quality deterioration. In order to better understand the relationship between microstructure and ice crystals and obtain high quality food products, it is critical to effectively measure and control the behavior of ice crystals. In the current review, the principles of measuring methods including optical and electron microscopy, electromagnetic spectroscopy, differential scanning calorimetry (DSC) and online techniques are introduced, novel technologies based on ultrasound, high pressure, and electromagnetic fields, as well as biological proteins to control the formation of ice crystals by inducing or suppressing ice crystallization are presented. Future prospects on measuring and controlling ice crystallization are also discussed. By obtaining the moisture behavior information with NMR, Raman and DSC and direct images or network structure of ice crystal, these direct and indirect measurements can characterize ice crystals in multi-perspectives, providing constructive information on the mechanisms of the freezing process. In addition, advanced novel freezing technologies show great promise in improving the crystallization process during freezing of foods. It is thus hoped that this review could provide better understanding on ice crystallization in frozen products, leading to the optimization of the freezing process for the frozen food industry. • We discussed quality loss and microstructure damage due to ice crystal formation. • We presented different techniques to observe crystalline structure. • We assessed novel technologies to control ice crystallization. • Nondestructive and online detection are inevitable trends in future studies. • Future efforts should be made to industrialize freezing assisting technologies. [ABSTRACT FROM AUTHOR]

Abstract This work aimed at evaluating the effects of high-voltage electric field (HVEF) produced by an improved electrode system on the freezing behaviors and selected properties of agarose gel. The freezing of the agarose gel was realized by a Peltier cooler coupled with an improved electrode system. The electrode system was integrated with a dielectric spacer having high permittivity to avoid partial discharges. Results showed that HVEF combined with a low freezing rate significantly reduced the supercooling degree, enhanced the average freezing rate in particular the nucleation rate, and higher internal electric field intensity showed a better microstructure with smaller ice crystals in frozen samples. Under the highest applied voltage of 9 kV ( E i n = 1.09 E+05 V/m) tested in this study, a 100% supercooling release was achieved. Maximum reductions of 78.83%, 25.79% and 28.75% were observed for the nucleation time, tempering time and total freezing time, respectively, while the phase transition time was prolonged by 14.86% as compared with the control (p < 0.05). Some reinforcement was detected in the gel strength by increasing internal electric field intensity, but not significant enough to prevent the structural damage and syneresis caused by freezing and thawing. This study suggested that HVEF-assisted freezing was able to reduce the size of ice crystals formed in semi-solid model foods, and the integration of a dielectric spacer with high permittivity to the electrode could be used as a potential method to solve the electrical discharge problem. Highlights • An improved electrostatic freezing (EF) system was developed. • Electrodes with dielectric spacer could strengthen the internal field intensity. • EF reduced supercooling degree and enhanced freezing rate. • EF enhanced gel strength but did not prevent freezing damage. • EF reduced the size of ice crystals formed in agarose gel. [ABSTRACT FROM AUTHOR]

• Pathogenesis of pear infected by A. alternata was monitored by HSI. • HSI was successfully used for early identification of pear black spot disease. • Spectral angle mapper was used to identify and segment the fruit infected area. • SVM model had better classification accuracy for early detection of disease. Pathogenetic process monitoring and early detection of black spot disease caused by Alternaria alternata on pear fruit is still difficult, as it causes only minor changes in the appearance of the infected area during the early stages of infection. In this study, the potential of hyperspectral imaging (HSI) for monitoring the pathogenetic process and early detection of the disease on pear fruit was evaluated. Fresh Korla pears were inoculated with Alternaria alternata and hyperspectral images were acquired from infected and control samples. Spectral angle mapping was performed to segment the infected area from sound tissue, and to monitor the pathogenetic process of the disease. Support vector machine (SVM), k-nearest neighbor, and partial least squares discriminant analysis models were developed and evaluated for their ability to detect early onset of the disease. Results concluded that the SVM model with an overall accuracy of 97.5% was most suitable for the proposed HSI technique. This study is the first reported attempt to use HSI to monitor the pathogenetic process and detect the early symptom of the disease in pear fruit. [ABSTRACT FROM AUTHOR]

[Display omitted] • 2D-image data were obtained from 1D-spectra data using GASF, GADF, MTF and RP. • 1D-CNN and 2D-CNN models were developed to distinguish PCRs of different origins. • Con-CNN and Add-CNN models were built to fuse 1D-spectra data and 2D-image data. The geographical indication of pericarpium citri reticulatae (PCR) is very important in grading the quality and price of PCRs. Therefore, terahertz time-domain spectroscopy (THz-TDS) technology combined with convolutional neural networks (CNN) was proposed to distinguish PCRs of different origins without damage in this study. The one-dimensional CNN (1D-CNN) model with an accuracy of 82.99% based on spectral data processed with SNV was established. The two-dimensional image features were transformed from unprocessed spectral data using the gramian angular field (GAF), the Markov transition field (MTF) and the recurrence plot (RP), which were used to build a two-dimensional CNN (2D-CNN) model with an accuracy of 78.33%. Further, the CNN models with different fusion methods were developed for fusing spectra data and image data. In addition, the adding spectra and images based on the CNN (Add-CNN) model with an accuracy of 86.17% performed better. Eventually, the Add-CNN model based on ten frequencies extracted using permutation importance (PI) achieved the identification of PCRs from different origins. Overall, the current study would provide a new method for identifying PCRs of different origins, which was expected to be used for the traceability of PCRs products. [ABSTRACT FROM AUTHOR]

• A high-sensitivity Au@AgNRs/CMC/qPCR flexible film SERS substrate was fabricated. • Au@AgNRs was synergistically stabilized and protected by CMC and qPCR bilayer film. • CMC stabilized Au@AgNRs through coordination of –COO– groups with surface Ag atoms. • qPCR film act as carrier and barrier to prevent Au@AgNRs from oxidation and damage. • The substrate was used for in-situ sampling and detection of thiabendazole on fruits. In this study, a high-performance, stable and homogeneous Au@AgNRs/CMC/qPCR flexible film surface-enhanced Raman scattering (SERS) substrate was constructed by synergistically stabilizing and protecting bimetallic core–shell Au@Ag nanorods (Au@AgNRs) with carboxymethylcellulose (CMC) and fluorescent-quantitative-polymerase-chain-reaction (qPCR) film. The network structure of CMC immobilized and aligned Au@AgNRs through coordination of carboxyl groups with surface Ag atoms to provide intensive and stable 'hot spots', and the qPCR bilayer film performed as carrier and barrier to protect Au@AgNRs from oxidation, humidity and optical damage and improved the robustness and stability. The Au@AgNRs/CMC/qPCR film was used for in-situ extraction and SERS detection of thiabendazole on nectarine (0.24 ppm) and lemon (0.27 ppm) with low detection of limits. Furthermore, it retained 98.6% SERS performance after storage for 90 days under ambient conditions, revealing the great potential in promoting the commercialization of the SERS technique for sensitive contaminants sensing with simple fabrication procedures, homogeneity, reproducibility and long-term stability. [ABSTRACT FROM AUTHOR]

An isoreticular principle guides the directed evolution of domino reactions in MOF nanozymes against antibacterial resistance. The Ce-UiO-66 nanozymes, with linker-dependency on dual hydrolytic and redox mimicry, couple ATP depletion and ROS generation into a unique biofilm microenvironment-responsive prodrug-mimicking domino reaction, enabling the kinetically favourable Ce-UiO-66-NO 2 to effectively target and inhibit MRSA biofilm at the initial bacterial adhesion stage. [Display omitted] • Isoreticular chemistry accelerates the directed nanozyme discovery of Ce-MOFs. • Linker dependence Ce-UiO-66-X modulates dual apyrase and oxidase biomimicry; • Domino effect of the hydrolytic and redox activities in Ce-UiO-66-X is revealed; • Domino reaction in Ce-UiO-66-X couples ATP hydrolysis and ROS generation; • Ce-UiO-66-X enables microenvironment-responsive disinfection of MRSA biofilm. Nanozyme therapy holds promise for overcoming daunting antimicrobial resistance, but skills to target the microbial microenvironment are lacking. Herein, an isoreticular principle was introduced in nanozyme discovery to directedly evolve a domino biomimetic reaction specific to drug-resistant bacterial biofilm. The isoreticular Ce-UiO-66-X (X = BDC, BDC-CH 3 , BDC-OH, BDC-NH 2 , BDC-NO 2 , ADC, Fum) MOFs exhibited linker-dependent mimicry of hydrolytic apyrase and redox oxidase, and the phosphorous reactants (ATP/ADP/AMP/Pi) produced by the ATP hydrolysis could spontaneously activate redox reaction in Ce-UiO-66-X. Evidenced by the representative Ce-BDC-X (X = –NO 2 , -H, and –NH 2) nanozymes, the unique domino reaction of Ce-UiO-66-X could simultaneously deplete ATP molecules and trigger enhanced generation of superoxide radicals at the specific time window in the initial bacterial adhesion stage of methicillin-resistant Staphylococcus aureus (MRSA) biofilm formation. Due to the synergistic nanocatalytic mechanism, possible nanoscale penetration effect, and good biocompatibility, Ce-UiO-66-NO 2 could effectively target and destroy the metabolic microenvironment of MRSA biofilm in vitro and in vivo, reducing the MRSA biofilm viability to as low as 3.64%. This work demonstrates a new prodrug-like enzymodynamic antibacterial therapeutics based on cooperative multienzyme reactivity. [ABSTRACT FROM AUTHOR]

Freezing reduces the temperature of the food system and extends the shelf life of food. However, the inevitable formation of ice crystals could impact food quality. Small-size ice crystals are more acceptable in frozen foods than large aggregates with irregular shapes. Undesired ice crystals could not only change food structure and cause serious quality deterioration, including texture alteration, nutrient loss and off-flavour. Ice-regulating materials have been proven to regulate ice nucleation, growth and recrystallization, which show promising applications in the food industry. The theoretical information on ice formation, particularly ice nucleation and recrystallization, was described. Current ice-regulating materials, such as active proteins, saccharides, and natural deep eutectic solvents (NADES), and their mechanisms of regulating ice formation were summarized. Based on the ice damage to foodstuffs with different microstructures, the applications of active ice-regulating materials in improving the quality of frozen food were also discussed. Ice-regulating materials showed superior actions in regulating ice formation and their addition alleviated ice damage and improved the quality of frozen foods by accelerating or inhibiting freezing. Moreover, the current challenges and future perspectives of ice formation regulation for high-efficiency food freezing were proposed. • The theory of ice nucleation and recrystallization is presented. • The mechanisms of ice-binding materials regulating ice formation are summarized. • Ice-binding materials enhance the quality of frozen food. • The safety concerns of ice-binding materials as food ingredients are discussed. • Challenges and perspectives of ice regulation for food freezing are proposed. [ABSTRACT FROM AUTHOR]

• THz-TDS was applied on an MVD system for in-situ MC evaluation of samples. • PE hoses could be integrated into the MVD system to perform THz sensing. • Moisture vapor exhausted from desiccator was correlated with MC loss of samples. • Real-time MC in both beef and carrot samples during MVD was accurately predicted. Moisture content (MC) is a critical quality indicator for food drying processing, however achieving in-situ non-destructive analyses of dynamic MC of products during processing is still a challenge. This study developed an in-situ indirect measurement method using Terahertz time-domain spectroscopy (THz-TDS) for real-time MC prediction of foods during microwave vacuum drying (MVD). During MVD, THz-TDS continuously sense the dynamic moisture vapour from the desiccator through a polyethene air hose. The obtained THz spectra were processed to calibrate MC loss prediction models using support vector regression, Gaussian process regression and ensemble regression. Then the MC was calculated using moisture loss prediction results. The best real-time MC prediction results for beef and carrot slices achieved R2 of 0.995, RMSE of 0.0162, and RDP of 22. The developed system provides a novel method for drying kinetics research during MVD and expands the applicability of the THz-TDS technique in the food industry. [ABSTRACT FROM AUTHOR]

Blueberry is a class of berries with high nutritional and economic value but has short shelf life due to its rapid softening at room temperature. This study investigated the effects of plasma-activated water (PAW) treatment on the softening quality and cell wall pectin metabolism of blueberries stored for 10 d at 25 °C after being immersed in PAW for 10 min. PAW was generated by plasma with different times (1 and 2 min), fixed frequency (10 kHz) and fixed voltage (50 kV). The analysis showed that the firmness of PAW-treated fruit significantly increased (P < 0.05) by 36.4% after 10 d storage. PAW treatment controlled the solubilization of pectin from water-insoluble to water-soluble. The activities of cell wall pectin-degrading enzymes like polygalacturonase (PG), β -galactosidase (β -Gal) and pectin methylesterase (PME) in PAW-treated blueberries decreased by 15.7%, 18.3%, and 27.9%, respectively, on day 10. After PAW treatment, blueberries also maintained better postharvest quality (firmness, colour, soluble solid content and anthocyanin content) and intact epidermal waxy and cell wall structure. These results suggested that PAW showed great potential for postharvest fresh-keeping of blueberry. • Plasma-activated water was an effective method for preserving blueberries. • Plasma-activated water could delay blueberries softening. • Cell wall degrading enzymes activities were inhibited by plasma-activated water. • Plasma-activated water could inhibit cell wall pectin fractions degradation. • Plasma-activated water protected the epidermal waxy structure of blueberries. [ABSTRACT FROM AUTHOR]