Search

Herein, the potential of watermelon rind (WMR) biomass for bio-ethanol production through an integrated bioprocess consisting of combinative sequential ultrasonication and deep eutectic solvent (DES) pretreatments, enzymatic hydrolysis and fermentation was investigated. For the improvement of the efficiency of the WMR conversion into bio-ethanol, the effectiveness of the ultrasonic-assisted DES pretreatment on bio-ethanol yield was studied by optimization, adopting Central Composite Rotatable Design. Glucose was the most dominant sugar in the WMR biomass which enhanced its suitability as cheap carbon source for fermentation process. Maximum glucose and total reducing sugar yields of 60.17 % and 83.03 % were respectively obtained, and the enzymatic hydrolysis efficiencies ranged from 75.79 to 91.13 % . The bio-ethanol yield ranged from 0.276 to 0.458 g g − 1 raw WMR, corresponding to fermentation efficiencies of 54.12–89.80 % , with the maximum obtained at ultrasonication power 180 W , ultrasonication frequency 40 k H z , ultrasonication time 40 m i n , DES reaction temperature 120° C and DES reaction time 180 m i n . Results showed that all the pretreatment factors considered had significant effect on bio-ethanol yield. It was established that combinative pretreatment was efficient for delignification, solubilization and hydrolysis of cellulose and hemicellulose into monomeric sugars by removing hemicellulose from the cellulose fibers. This enhanced fermentable sugar recovery, which consequently increased bio-ethanol yield.

This study aimed to develop zein/chitosan-based films formulated with curcumin and eugenol to improve the quality of postharvest blueberries. First, the film-forming solutions were characterized (rheological property and water distribution), and the mechanical, structural properties and bioactivity of active films fabricated by casting were evaluated. Further, the active film was coated with blueberry stored at 4 °C, and physicochemical properties (weight loss, hardness, microbial counts, and appearance changes) were measured. The film-forming solutions exhibited non-Newtonian behavior. The incorporation of curcumin and eugenol improved the tensile strength and elongation at the break of films, reaching 17.86 MPa and 92.80 %, respectively. The antioxidant capacity was enhanced, and DPPH and ABTS radical scavenging rates were up to 90.60 ± 0.06 % and 86.34 ± 0.39 %, respectively. Meanwhile, the prepared active films possessed good anti-UV and sensitive pH-response color-shifting ability. Compared to the uncoated blueberry, blueberry coated with zein/chitosan/curcumin/eugenol showed lower weight loss and higher hardness, indicating that the prepared active films played a vital role in delaying the deterioration of blueberry and extending its shelf life. Overall, the zein-chitosan incorporated with curcumin and eugenol films could be a promising candidate to prolong the shelf life of food products due to their excellent bioactive capacity.

This paper aims to evaluate the impact of simultaneous tri-frequency ultrasound (20 + 40 + 60 kHz) combined vacuum (0.6 bar) assisted ethanol (75%) pretreatment on the infrared drying process, qual...

As part of finding a mechanism to ameliorate the decomposition of phytochemicals and antioxidant in drying processing, this research was conducted. To achieve this, pineapple slices was dried using relative humidity (RH) dryer at varied temperature (60–80 °C) combined with RH (10–30%) conditions. The results revealed that higher RH retained with significantly difference (p

The influence of freeze and convection (at 40 and 50 °C) drying on the physical, functional, and rheological attributes of sunflower protein (SP) and its hydrolysate (SPH) was investigated. Compared with convectively-dried samples, the lightness, turbidity, bulk density, and particle size values of the freeze-dried SP and SPH were substantially higher, but the browning index was lower (p < 0.05). Additionally, freeze-dried samples exhibited good solubility and foaming characteristics, whereas lower emulsion properties with the most pH values were observed. Furthermore, SPHs possessed higher solubility as well as foamability over SPs under varying pH values (2.0–10.0), whilst reduction in the emulsion activity index was clearly observed (p < 0.05). Convectively-dried powders exhibited greater viscosity and consistency coefficient; and significantly lower flow behavior index of dispersions, relative to the respective freeze-dried preparations, indicating that dehydration methods influenced the flow behavior of the investigated samples. From a molecular weight analysis, convectively-dried samples at various temperatures were characterized with high proportion of small-sized particles at ≤1 kDa fractions over the respective powders obtained by freeze drying. The observations made, thus, would benefit food processors and manufacturers in electing better dehydration technique based on the desired traits of SP and SPH powders for successful application in food product formulations.

Alicyclobacillus acidoterrestris (AAT) was proposed as an index of pasteurization design for high-acid fruit products due to its spore resistance and repeated spoilage incidences in fruit juices. This study aimed to determine the effectiveness of pulsed multifrequency ultrasound to minimize AAT spores and vegetative cells in aqueous suspension. For this research, an investigation of the reactive oxygen species and antioxidant activity was performed to examine the effect of temperature and frequency on AAT spore inoculation. Total decreases in AAT bacteria were 5.99, 5.74 Log CFU/mL in vegetative cells for dual-frequency thermosonication (DFTS) and dual-frequency ultrasonication (DFUS), respectively, while 5.90 and 5.38 Log CFU/mL in spores for both DFUS and DFTS, respectively. The loss of the percentage of cells in ultrasound (US) and thermosonication (TS) treatments was inversely associated with the rate of O

Background The change of surface color caused by browning during the drying process of shiitake mushroom seriously affects its market circulation. Intensive pulsed light (IPL) as a non-heat treatment method can reduce enzyme activity by changing the enzyme structure. Therefore, in this study, the use of IPL pretreatment before drying was aimed to reduce the adverse reactions caused by browning reaction during the drying processing of shiitake mushroom. Results Shiitake mushroom pretreated with IPL energy of 400 J for 25 pulse numbers reduced the initial PPO enzyme activity, the browning index (BI) and browning degree (BD) values by 42.83 %, 43.02 % and 47.54 %, respectively. The IPL pretreatment enhanced the polysaccharides and reducing sugars contents (RSC) while it reduced 5-hydroxymethylfurfural (5-HMF) generation in the dried shiitake mushroom. The pretreatment also improved the surface color, the antioxidant activity and retained the umami taste characteristics in the dried shiitake mushroom. Conclusion The IPL pretreatment combined with the controlled temperature and humidity for convection drying could be a suitable method to improve the quality of dried shiitake mushroom. Therefore, this study provides a new pretreatment method for materials that are prone to browning during drying. This article is protected by copyright. All rights reserved.

This is the first time to investigate the synergistic inactivation effect and mechanism of multifrequency ultrasound (MTUS) on A. acidoterrestris (AAT) vegetative cells and spores, nutrients and enzymes of orange juice. The optimized results of MTUS (using Box Behnken design- surface response methodology) and further comparison with different mode of ultrasound (mono-and multi-frequency) revealed that 20/40 kHz, 24 min and 64 °C were the best optimum results. The AAT spores and vegetative cells were inactivated by 2 and 4 logs, respectively, without deteriorating orange juice contents. In addition, AAT inactivation indicated an inversely proportional relationship with ROS production. FT-IR and UV–Vis spectroscopy characterization confirmed the existence of ROS in treated orange juice and LF-NMR analysis confirmed the inactivation of AAT spores. The findings illustrated the successfully used dual-frequency ultrasound technology for fruit beverages, promoting beneficial changes in physical properties without any significant effects on the quality of ascorbic acid.

The research work investigates the effect of different pretreatment conditions (osmotic dehydration [OD], ultrasound [US], and ultrasound-assisted osmotic dehydration [UOD]) on the drying kinetics modeling, thermodynamics, weight reduction, degradation kinetics of vitamin C, and color of apple slices under pulsed vacuum dryer (PVD). The findings showed that UOD pretreatment significantly improved drying time and increased weight reduction comparative to OD, US, and the control sample. Drying kinetics modeling revealed that the Hii model better described the drying kinetic behavior of the apple slices than the other nine mathematical models based on higher coefficient of determination (R2 ), root mean square error (RMSE), and reduced chi-square (χ2 ). Analysis of vitamin C content revealed a 46.05%, 31.28%, and 25.95% retention for UOD, US, and OD, respectively, after drying. Second-order kinetics could accurately predict the degradation kinetics of vitamin C compared to first-order kinetics. Vitamin C degradation kinetics showed lower k-value, higher D-value (time required for 90% degradation), and half-life indicating a higher retention of vitamin C content for UOD pretreatment compared to OD and US during drying. L*, b*, and chroma values of UOD were significantly (P

Highlights • Ultrasound freeze-thawing pretreatments improved the vacuum freeze-drying. • Pretreatment reduced the drying time and energy consumption. • Pretreatment changed the microstructure to various extent. • Ultrasound pretreatment retained most of the quality characteristics. • Pretreatment had no effect on the function groups and structure of pectin., Vacuum freeze-drying is a new and high technology on agricultural product dehydrating dry, but it faces the high cost problem caused by high energy consumption. This study investigated the effect of ultrasound (US), freeze-thawing (including the freeze-air thawing (AT), freeze-water thawing (WT), freeze-ultrasound thawing (UST), and freeze-air ultrasound thawing (AT + US)) pretreatments on the vacuum freeze-drying efficiency and the quality of dried okra. The results indicated that the application of ultrasound and different freeze-thawing pretreatments reduced the drying time by 25.0%–62.50% and the total energy consumption was 24.28%–62.35% less. The AT pretreatment reduced the time by of okra slices by 62.50% and the total energy consumption was 62.35% less. The significant decrease in drying time was due to a change in the microstructure caused by pretreatment. Besides, the okra pretreated with the US retained most of the quality characteristics (flavor, color, hardness, and frangibility) among all methods, while, AT + US had the most changeable characteristics in quality, which is deprecated in our study. The okra pretreated with the US and AT, separately, had the best dry matter content loss (9.008%, 5.602%), lower chlorophyll degradation (5.05%, 5.44% less), and higher contents of total phenolics, total flavonoids, and pectin, with strong antioxidant capacity, compared to other methods. The pretreatments did not have a large effect on the functional groups and the structure of pectin, but slightly affected the viscosity. It can be concluded that AT and US pretreatment methods are better than others.

Ultrasound requires high power and longer treatment times to inactivate microorganisms when compared to ultrasound combined with other technologies. Also, the antimicrobial efficiency of aqueous ozone increases with an increase in its concentration and exposure time, but with a detrimental effect on the quality of the treated food. In this study, the effect of aqueous ozone at low concentration, multi-mode frequency irradiation and their combination on microbial safety and nutritional quality of cherry tomato was investigated. Individual washing with aqueous ozone and mono-mode frequency irradiation resulted in1 log CFU/g reduction in the spoilage microorganisms, while dual-mode frequency irradiation (DMFI) resulted in higher microbial reduction (1.3-2.6 1 log CFU/g). The combined system (20/40 kHz + aqueous ozone) on the other hand, resulted in3 log CFU/g microbial reduction. The application of DMFI enhanced the antimicrobial efficiency of aqueous ozone without any detrimental effect on the physicochemical properties (except the firmness), bioactive compounds, and antioxidants of the cherry tomato during 21 days refrigerated storage. The result obtained indicates the promising substitute to the single washing technique for microbial safety as well as preserving the nutritional quality and enhancing the shelf life of cherry tomato.

Effect of mono and dual frequency (20, 28 and 20/28 kHz) ultrasound action on extraction kinetics, functional, and structural traits of sunflower protein (SP) was examined. A simplified model based on Fick's second law was developed, and the mass transfer of soluble SP in a heterogeneous system was successfully described. Findings suggested that ultrasound action significantly increased (p Industrial relevance Sunflower protein, isolated from sunflower residue, is a potentially low-cost resource for food applications. Ultrasonication is reported to improve the extraction of proteins as well as enhancing their functionalities. The existing study displayed that ultrasonication (observably dual frequency treated) was successfully applied to improve the extractability of soluble sunflower protein, and enhanced its functionality (solubility and OHe) reference to control. The research outcomes may benefit food/ chemical industries in extraction and/or alteration of sunflower protein in new applications.

In recent years, nanocellulose from a wide range of sources has attracted extensive attention. Nanocellulose is mainly divided into three categories: nanofibrillated cellulose (NFC), nanocellulose crystals (NCC), bacterial nanocellulose (BNC), which can be obtained by physical method, chemical method, biological method. Nanocellulose is an ideal nanomaterial in many fields due to its biodegradability and other properties. This paper is divided into two parts, focusing on the application and challenges of NFC and NCC in the food field and the application and challenges of BNC in the food field.

In this study, effects of conveyor belt catalytic infrared blanching (CBCIRB) on peroxidase (POD), moisture reduction, physical and chemical properties, and microstructure of sweet potato slices were investigated. The parameters of CBCIRB were infrared irradiation distance (6, 12, and 18 cm), sample thickness (3, 5, and 7 mm), and conveyor speed (0.7, 0.35, 0.1 m/min, etc.). Meanwhile, the effect of conventional hot water blanching (HB) on sweet potato slices were also investigated. The results showed that shortening the infrared irradiation distance and reducing the slice thickness could both accelerate the POD inactivation rate. When 90% POD inactivation was achieved, CBCIRB samples yielded better hardness and higher preservation of phytochemicals than HB samples. The appropriate CBCIRB parameters were the slice thickness of 3 mm, infrared radiation distance of 12 cm and conveyor belt speed of 0.16 m/min, the moisture reduction, surface colour change, hardness, vitamin C retention rate, β-carotene retention rate, and total phenol content were: 78.34%, 7.41, 1690.4 g, 75.16%, 133.49%, and 1.03 mg/g, respectively. The microstructure observation showed that the damage of sweet potato slice cells by HB was more severe than CBCIRB. Overall, CBCIRB achieved higher product quality in a relatively uniform air environment.

The higher heating value (HHV) and exergy of ultrasound-assisted deep eutectic solvent pretreated watermelon rind (WMR) biomass were investigated. Thereafter, the co-pyrolysis of the WMR biomass and coal blends was studied. The pyrolysis kinetics and thermodynamic parameters of the WMR-coal blends were determined using four isoconversional models (Flynn-Wall-Ozawa, Kissinger-Akahira-Sunose, Friedman and Starink). The HHVs of the pretreated WMR ranged between 12.73 and 19.28 MJ/kg, while the exergy value for the raw and pretreated WMR were 16.08 and 21.55 MJ/kg, respectively. The lower heating value related exergy had the greatest influence on the overall exergy of the WMR. The values of the pre-exponential factor showed variations in wide range, and the change in entropy of the system displayed both negative and positive entropies. The activation energy and enthalpy varied directly with the amount of coal in the blends. Amongst the isoconversional model methods, Friedman model was the best predictor of the kinetic parameters.

The influence of ultrasound‐ethanol (US‐E) pretreatment durations (10, 20, and 30 min) on apple slices dried with varied temperatures (60, 70, and 80°C) using pulsed vacuum dryer was investigated. The results showed that untreated sample (control) took 375, 325, and 225 min to achieve a constant weight of drying whereas drying time for 30 US‐E samples were 275, 225, and 175 min, indicating that 30 US‐E reduced the total drying time by 26.66, 30.77, and 22.22% at 60, 70, and 80°C, respectively. Moisture effective diffusivity and activation energy were in the range of 1.98–4.08 × 10⁻⁸ m²/s and 12.58–23.43 kJ/mol, respectively. Color (L*, a*, b*) and texture were affected significantly (p

Cherry tomato fruits were treated with three dual‐frequency ultrasound (US) at different temperature and time. The three treatment variables, that is, dual‐frequency US, temperature, and time were optimized with the aid of response surface methodology (RSM). About 20/40 kHz, 52°C, and 6 min were the optimum condition obtained for total bacteria count (TBC, 1.08 log cfu/g), firmness (15.90 N), and total phenolic content (TPC, 34.34 mg GAE/100 g). All the linear relations of the treatment variables showed a significantly negative and positive effect on the TBC and TPC, respectively, while positive significant effects were obtained for some of the relations of the firmness. Hence dual‐frequency sonication is effective for microbial safety and maintaining the quality of cherry tomato. Also, RSM was found to be a useful tool in setting and optimizing the variables responsible for sonication treatment. PRACTICAL APPLICATIONS: Thermosonication (ultrasonication and heat) has been applied toward improving the microbial safety and nutritional quality of vegetables and fruit. However, factors such as power, frequency, time, temperature, etc. determine the efficiency of its operation. Controlling these factors is difficult and therefore requires a robust and efficient optimization tool in determining their effects (individual and interactions) on food during treatment. In this study, response surface methodology provides the solution in settling and optimizing the variables for the sonication treatment. Besides, the remarkable result obtained in this work offers an alternative to the combined use of ultrasound and chemical in food industries.

Policy Guidance Program (Research Cooperation) of Jiangsu, Grant/Award Number: BY2016072‐03; National Key Research and Development Program of China, Grant/Award Number: 2017YFD0400903‐01, 2016YFD0400705‐04, and 2018YFD0; Science and Technology Major Project of Anhui, Grant/Award Number: 18030701152; Social Development Program (General Project) of Jiangsu, Grant/Award Number: BE2016779, NY2017015

Science and Technology Major Project of Anhui, Grant/Award Number: 18030701152; Social Development Program (General Project) of Jiangsu, Grant/Award Number: BE2016779 and NY2017015; Policy Guidance Program (Research Cooperation) of Jiangsu, Grant/Award Number: BY2016072-03; National Key Research and Development Program of China, Grant/Award Number: 2016YFD0400705-04, 2017YFD0400903-01 and 2018YFD0700101-02

This work aimed to study the rehydration characteristics of vacuum freeze- (VFD) and hot air-dried (HAD) garlic slices and explain the rehydration mechanism. It was observed that VFD samples had significantly faster water absorption rates than HAD samples. However, VFD samples had lower final moisture contents than the HAD samples. Additionally, the effect slice thickness on rehydration characteristics of samples was lower than that of drying methods. The contact angle and microstructure analysis of dried samples revealed that the strong water wettability and the porous structure contributed to the faster water absorption rate of VFD samples. Moreover, we found and confirmed, for the first time, that numerous air bubbles trapped in the VFD samples hindered the absorption of water. This resulted in a lower water holding capacity in VFD samples compared with HAD samples, which had less air bubbles.

The low molecular weight (≤3 kDa) collagen peptide (CPLW) was prepared from white carp skin by intestinal simulation digested and ultrafiltration membranes. CPLW and calcium ions were combined to form a peptide-calcium complex (CPLW-Ca), and the structure and stability of the complex were characterized. The single factor optimization results indicated that the highest protein conversion rate and the maximum calcium binding ability were 60%, and 22.16 ± 0.55 mg/g, respectively. Structural analysis demonstrated that calcium ions bound to CPLW mainly via the formation of ionic bonds with carboxyl oxygen, hydroxyl oxygen and amino nitrogen atom of CPLW. The CD and particle size analyses showed that after CPLW was combined with calcium ions, the spatial structure was folded, which reduced the particle size with the formation of irregular nanoparticles. Stability analysis revealed that the calcium retention rate of the prepared CPLW-Ca remained substantially at 90% below 90 °C, and the calcium content of CPLW-Ca was significantly decreased under high acidic conditions. CPLW-Ca has the potential to be applied as an alternative for dietary calcium supplements.

Sequential delignification of watermelon rind using ultrasonication and deep eutectic solvent (DES) pretreatment methods was demonstrated in this study. The effects of pretreatment factors on delignification were investigated using parametric screening and subsequent optimization of significant factors. Plackett–Burman Design was used for the screening of pretreatment variables, while optimization was performed adopting Central Composite Rotatable Design. For the range of variables considered in the study, the screening experiments revealed that the effects of ultrasonication power, ultrasonication frequency, ultrasonication time, DES reaction temperature and DES reaction time on delignification were significant, while the effects of ultrasonication solid-liquid ratio, ultrasonication temperature, hydrogen bond acceptor/hydrogen bond donor molar ratio, and DES solid-to-liquid ratio were not significant. The significant factors were further investigated and maximum lignin removal of 43.56 % was achieved at ultrasonication power 180 W , ultrasonication frequency 60 k H z , ultrasonication time 40 m i n , reaction temperature 120° C and reaction time 180 m i n . Synergistic effect between the two pretreatment methods was observed and it correlated positively with the severity of the ultrasound pretreatment. The SEM and FTIR analyses further established the effectiveness of the sequential combinative pretreatment methods on watermelon rind delignification.

The effects of moderate thermosonication (MTS) on the quality quartet: physico-chemical, microbial, nutritional and sensory qualities of orange juice (OJ) inoculated with Alicyclobacillus acidoterrestris (AAT) were studied during 24 days of storage at ambient and refrigerated temperatures. The bioactive compounds and antioxidant activity of OJ decreased with storage, while the pectin methyl esterase (PME) increased. Nonetheless, noticeable changes were observed from the 12th day of storage. There was no obvious (p > 0.05) variation in pH and total soluble solids. To determine the nutritional and microbial quality characteristics of OJ during storage, non-linear kinetic curves were successfully fitted with least square fitting polynomial and four-parameter log-logistic distribution models. The E-nose sensors succeeded in discriminating between the aroma of non-treated and treated OJ based on linear discriminant analysis (LDA). Furthermore, terpenes, alcohol and partially aromatic compounds were the main spoilage indicators of OJ during storage based on E-nose analysis and confirmed by HS-SPME-GC/MS analysis. Thus, MTS significantly extended the shelf life of the quality quartet of natural OJ at 4 °C. E-nose-GC/MS fusion offered odor fingerprints to AAT microorganisms that can be used as spoilage index without using traditional food analysis techniques. The proposed approach can be used as an alternative tool for rapid detection of spoilage microorganisms in OJ.

The suitability of some non-linear kinetic models (Weibull {with or without tail}, Log-linear, Log-linear shoulder {with or without tail}, Biphasic linear, Logistic, Multi-target and Single-target models) were evaluated to determine the inactivation kinetics of inoculated E. coli, and natural microbiota (i.e. mesophilic aerobic bacteria, and mold and yeast) on cherry tomato treated with fixed multi-frequency ultrasound. Almost all the studied model fitted well (R2 ≥ 0.9) for the inactivation kinetics; however, the Weibull, Log-linear shoulder, and Biphasic linear model showed the highest statistical parameters (0.9 ≤ adj. R2 ≤ 0.99 and smallest RMSE and SSE values). All the three models could be used to compare the kinetic behavior of E. coli and the first two models for the kinetic behavior of mesophilic aerobic bacteria and mold and yeast during sonication treatment. Two distinctive inactivation curves were obtained for the mono-frequency and the multi-frequency (dual and tri-frequency) for all the microbial inactivation. The remarkable results obtained for dual and tri-frequency sonication shows to be an effective and promising alternative to the traditional microbial inactivation techniques and the common practice of using ultrasound with other sanitizing methods.

Refrigeration is an effective means of reducing losses in fresh fruit; however, its efficacy as a means of preservation is mostly limited to crops that are not vulnerable to chill injury. Cherry tomato is one of these crops where other supporting processes or storage alternatives are sought. The effect of 10-min post-harvest treatment of cherry tomato with individual or combined application of dual-frequency ultrasound (20/40 kHz) and chemical sanitizers was investigated. The sanitizers used are 200 mg/L sodium dichloroisocyanurate (SD), 40 mg/L peracetic acid (PAA), 40 mg/L peracetic acid with 5% H2O2 (PAAH), and 5% hydrogen peroxide. The results showed that the treatments significantly reduced the natural microbiota (aerobic mesophiles and yeasts and molds) within the values of 0.29–3.10 log CFU/g. The highest inactivation was observed for the PAAH and ultrasound when applied as an individual (2.08–2.32 log CFU/g) and combined (3.07–3.10 log CFU/g) treatment. Also, the ultrasound and combined treatment resulted in higher retention of the total phenolic, and flavonoid contents, but with a loss in firmness of the cherry tomato. Nevertheless, during storage, the treatments when compared with the untreated samples, impede the loss in firmness. The other quality parameters such as pH, total soluble solids, titratable acidity, and maturity index were not affected, which signified that irrespective of the treatment, similar changes take place on the fruit during storage, especially in both control and chemically treated fruit. The combination of 40 mg/L PAAH and 20/40 kHz for 10 min caused ≥3-log CFU/g reduction of the natural microbiota. It mitigated the senescence of the cherry tomato during the refrigerated storage (4 °C), which thereby increased the shelf-life. The results obtained at the end of the storage thereby indicated that the combined treatments could guarantee microbial safety and retain the quality of the cherry tomato.