Search

Alicyclobacillus acidoterrestris (AAT) is a spore-forming bacterium that can survive thermal pasteurization and acidic conditions. Ultraviolet light emitting diode (UVLED) has received extensive attention as a new technology to replace traditional mercury lamps for fruit juice decontamination, however, very few studies on fruit juice have been reported to investigate the sporicidal effect of UVLED on A. acidoterrestris. This research investigated for the first time the application of UVLEDs at 254 nm for the treatment of AAT in tomato juice. The optimized conditions for UVLED, achieved with the aid of Box Behnken design, were 6 cm, 12 min, and 250 mL/min. The results showed that the AAT spores in citrate buffer solution and tomato juice were inactivated by 3-log reduction with a required fluence of 53.67 mJ/cm2. Additionally, UVLED induced an exclusively cellular damage through direct absorption of UV light and direct DNA damage, and indirectly via reactive oxygen species. Besides, the deactivation of AAT spores, validated by LF-NMR analysis, indicated that the free water in AAT might be due to the rehydration of the spore core by the process of germination and then dehydration. This dehydration was further confirmed by the shrinking of spores observed through SEM and AFM imaging. These outcomes were also correlated with those of potassium ions and DPA leakage. This study emphasizes the energy-saving and resistance-reducing features of UVLED in effectively inactivating AAT. • UVLED treatments was divided into multiple closed cycles in Dean flow system. • UVLED achieved a reduction of 3 log CFU/mL in AAT spores in tomato juice. • Potassium release explained a loss of intracellular compounds by cell damage. • DPA photosensitized spores and increased its photoproducts After UVLED. • LF-NMR revealed the rehydration of the spore core by germination. [ABSTRACT FROM AUTHOR]

A combined method of catalytic infrared (CIR) and intense pulsed light (PL) was investigated to settle a dispute of bacteriostasis on green Sichuan pepper (GSP), and the synergistic principle was elucidated from several aspects. The synergistic bacteriostasis was confirmed first on GSP by the plate counting method. On bacterial cells, leakage of cytoplasmic contents, intracellular protein and DNA breakages were investigated, and the difference between CIR and PL indicated the possibility of synergism. On a single bacterium, the expected synergy was not achieved on the plate but was obtained on GSP, and the bacterial cells treated by the combined method were mainly broken under SEM, indicating that the alliance technology could increase the damage of PL to bacterial cells on the rough surface of GSP. On multiple bacteria, synergy was obtained similarly, and the bacterial community on GSP was investigated with high-throughput sequencing. The community composition on GSP could be changed by the treatments. In conclusion, synergistic bacteriostasis on GSP was achieved by a combined method of CIR and PL, originating from a complementary effect on the microbiome and a promotion of bacteriostatic capacity on rough surfaces. These findings are expected to solve the bacteriostatic difficulty of spices with rough surfaces and have important implications for the development of effective bacteriostatic strategies in food preservation. • A combined CIR-PL conception was developed for bacteriostasis on rough surface. • A synergistic principle came from the promotion on rough surface by CIR pretreatment. • Another synergistic principle was interpreted based on microbiome complementarily. [ABSTRACT FROM AUTHOR]

[Display omitted] • DFTS induced A. acidoterrestris spore germination in orange juice. • Conductivity confirmed spore inner membrane (IM) damage by DFTS before germination. • Low DPA concentrations were achieved after 10 h incubation with L-alanine (L-ala). • TEM displayed IM poration and coat detachment of spore before L-ala germination. The off-odors associated with spoilage of acidic beverages are linked to the germination and growth of Alicyclobacillus acidoterrestris (AAT) spores. As a consequence, we determined the influence of nutrients, non-nutrient germinants, dual-frequency thermosonication (DFTS), and food matrix on spore germination. AAT spores in orange juice (OJ), supplemented by L-alanine (L-ala), had the highest germination rate and lowest DPA content at 10 h of incubation. The formation of microscopic pores in cell membranes during DFTS caused irreversible damage in AAT spores in citrate buffer solution (CBS); however, it stimulated AAT spore germination in CBS containing L-ala. Hence, the germination potential was established in the order: L-ala > Calcium dipicolinate > asparagine, glucose, fructose, and potassium ion mixture (AGFK) > L-valine. The conductivity analysis indicated that membrane damage could be a key factor contributing to the artificial germination in CBS. AFM images revealed that after 2 h of adding L-ala, the protein content increased with increased germinated cells. TEM showed that membrane poration and coat detachment were the main pre-germination morphological changes detected after DFTS treatment. This study provides evidence that germination stimulated with DFTS might be an effective strategy for reducing A. acidoterrestris spores in fruit juices. [ABSTRACT FROM AUTHOR]

• A review of co-pyrolysis of lignocellulosic and macroalgae biomass was conducted. • Synergistic interactions between the two co-feedstocks lead to high grade bio-oil. • Mechanism of co-pyrolysis in catalytic and non-catalytic reactions was explored. • Comprehensive analysis of the resulting bio-oil from the co-pyrolysis was conducted. • Implementation of catalytic co-pyrolysis for further bio-oil upgrading was studied. In recent years, there have been emerging studies on developing different techniques to improve the properties of pyrolysis bio-oil. One of such techniques is the co-pyrolysis of biomass with hydrogen-rich feedstock of higher fuel qualities. Co-pyrolysis aims to decrease the water and oxygen contents, increase the calorific and heating values, and eliminate the corrosion and instability problems associated with their direct use in boilers and turbines for heat and power generation and as a transport fuel. Lignocellulosic and macroalgae biomass feedstocks are complementary based on their different compositions, and this combination has been employed in co-pyrolysis techniques. In this review, the biomass feedstock characteristics and their effects on thermal conversion into bio-oil were discussed. Due to the heterogeneous nature of the two biomass feedstocks, investigations of their co-pyrolysis behaviour and their reaction mechanisms in both catalytic and non-catalytic reactions were explored. The synergistic effect which is the key reason behind the improvement in the yield and quality of bio-oil obtained from the co-pyrolysis of these biomass feedstocks was also examined. The resulting bio-oils from the co-pyrolysis were comprehensively analyzed and are characterized by improved properties than the pyrolysis of lignocellulosic or macroalgae biomass alone. However, due to thermal degradation, the existence of high oxygenated compounds in this pyrolysis bio-oil is a challenge that needs to be overcome. Catalytic co-pyrolysis could be implemented for additional upgrading of the pyrolysis bio-oil as liquid fuel for several purposes. Finally, the main bottlenecks, key solutions and future directions for the study were provided. [ABSTRACT FROM AUTHOR]

[Display omitted] • A.acidoterrestris (AAT) was inactivated by 5 logs via cell sonoporation. • Double-frequency ultrasound (DFUS) waves induced ROS and caused DNA damage. • Microstructure analysis showed that DFTS had a greater bactericidal effectiveness. • FTIR detected modifications in AAT proteins, nucleic acids and lipids, induced by ROS. 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 2 −and H 2 O 2 development. The fluorescence microscopy revealed a higher bactericidal efficacy of DFTS compared to the DFUS and control. Scanning Electron Microscopy (SEM) and Transmission electron microscopy (TEM) demonstrated ultra-structural modifications such as the interruption of cell walls by cavitation and pores in the membrane structure of the AAT bacteria induced by sonoporation. Several TS frequencies of 20/40/60, 20/40, and 20 kHz treated spores had a higher electrical conductivity than untreated ones, with an improvement of 7.94, 5.68, and 3.72 %, respectively. Fourier-transform infrared (FTIR) spectroscopy revealed major changes in the spectral region of membrane fatty acids and proteins of AAT. Simultaneously, AAT inactivation specific energy rate was significantly reduced using dual-frequency ultrasound, compared to mono-frequency thermosonication. The significant results of this work recommended pulsed DFUS as an alternative application to mono-frequency US in beverage industries. [ABSTRACT FROM AUTHOR]

• BBD-RSM optimized AAT inactivation spores and quality attributes of orange juice. • Best treatment inactivating AAT vegetative cells (4 logs) is TS-20/40. • Cells reduction by US and TS treatments correlated with O 2 •- and H 2 O 2 production. • FT-IR and UV–Vis spectroscopy can be used to detect ROS of TS treated orange juice. • LF-NMR confirmed dehumidification stimulated by sucrose explained AAT reduction. 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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [Display omitted] • Zein/chitosan-based active films were prepared successfully. • Eugenol and curcumin incorporation developed antibacterial/antioxidant properties. • Both the active films and film-forming solutions were characterized. • Mechanical properties were improved by containing eugenol and curcumin. • Active zein/chitosan-based film is a promising packaging for blueberry preservation. [ABSTRACT FROM AUTHOR]

Batch coupled enzymatic hydrolysis and membrane separation mode (BCEH-MSM) is efficient in preparing active peptides due to enzyme being more purposeful in hydrolysing macromolecular. Therefore, BCEH-MSM probably could be an alternative option to the traditional enzymatic hydrolysis and offline membrane separation mode (TEH-OMSM). This work aimed to explore the potential of BCEH-MSM in enhancing the enzymatic hydrolysis (EH) efficiency and the umami of the enzymatic hydrolysate. The EH efficiency was valuated based on product yields. Amino acid analyzer and HPLC were used to analyze tasting compounds. Electronic-tongue was used to determine umami intensity. The results showed that BCEH-MSM exhibited superior EH efficiency and higher umami intensity compared to TEH-OMSM. LC-MS/MS was used to identify peptides with higher umami intensity in the enzymatic hydrolysate. LGEETF, VNFDGEI, and QLSELLRAGSSPNL had umami profile verified by electronic-tongue. Molecular docking further showed that crucial amino acid residues involved in the binding to T1R1/T1R3 was His145. [Display omitted] • Batch coupled enzymatic hydrolysis and membrane separation improved yields and enhanced umami. • VNFDGEI, LGEETF and QLSELLRAGSSPNL exhibited umami taste characteristics. • His145 was a key binding site for umami peptides to TIR1/TIR3. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effect of vacuum freeze drying combined with catalytic infrared drying (FD-CIRD) process on aromas, free amino acids, reducing sugars and free fatty acids in chive leaves and stems. Gas chromatography-mass spectrometry combined with multivariate data analysis revealed that dipropyl disulfide was the key aroma that distinguished the differences between chive leaves and stems. The key aromas benzeneacetaldehyde, decanal and 1-octen-3-ol enhanced FD-CIRD chive leaves and stems aromas. The free amino acid content was highest at FD-CIRD stage in all samples except for the control (FD), while the reducing sugar content was lowest. The content of unsaturated fatty acids gradually decreased at FD stage and increased at FD-CIRD stage. Additionally, correlation analysis revealed that phenylalanine was a potential precursor of benzacetenealdehyde, oleic and linolenic acids were potential precursors of decanal and 1-octen-3-ol. Therefore, FD-CIRD technique helps to improve the sensory profile of dried chives. [Display omitted] • First study on aroma changes in drying chive leaves and stems. • Pearson reveals the relationship between aroma precursors and key aroma compounds. • Metabolic pathways of key aroma compounds hypothesized. • Benzeneacetaldehyde, decanal, and methional are key aromas in FD-CIRD chive leaves. • (E)-2-heptenal and 1-octen-3-ol are key aromas in FD-CIRD chive stems. [ABSTRACT FROM AUTHOR]

[Display omitted] • The HHV and exergy of pretreated watermelon rind (WMR) biomass were evaluated. • Co-pyrolysis of the WMR biomass and coal blends were studied. • Four isoconversional methods were employed to determine the kinetic parameters. • Activation energy & enthalpy varied directly with the amount of coal in the blends. • Among the models, Friedman method was the best predictor of the kinetic parameters. 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 / k g , while the exergy value for the raw and pretreated WMR were 16.08 and 21.55 MJ / k g , 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. [ABSTRACT FROM AUTHOR]

Ginger is susceptible to deterioration during storage, drying is an efficient approach to extend its shelf life. This research mainly aimed to investigate the effects of different osmotic pretreatments (NaCl solution osmotic (NOD), ultrasonic-assisted NaCl solution osmotic (UOD) and vacuum combined ultrasonic-assisted NaCl solution osmotic (VUOD)) and vacuum freeze-drying combined with hot air drying (FAD) on the drying time, rehydration ability, and physical and chemical properties of rehydrated ginger slices. Compared with single vacuum freeze-drying (VFD), vacuum combined with ultrasonic-assisted infiltration vacuum freeze-drying combined with hot air drying (VUOD-FAD) shortened the drying time by 59.75%. Rehydrated ginger treated with VUOD-FAD had a lower total color difference (5.65), and higher rehydration rate (4.89), with an odor that closer to the fresh sample's odor. Compared with the fresh sample, the chemical properties of the rehydrated samples had changed greatly. Compared with the rehydrated samples treated with VFD, FAD samples had higher gingerol content, 6-gingerol content, total phenol content (TPC), total flavonoids content (TFC), and oxidation resistance. It can be concluded that the processing method of VUOD-FAD is better than the other methods. [Display omitted] • The drying time of ginger treated with VUOD-FAD was significantly shortened. • The rehydrated ginger obtained by VUOD-FAD has an ideal overall appearance. • Rehydrated ginger obtained by VUOD-FAD treatment has a better odor. • Combined drying improved the biological activity of rehydrated ginger. [ABSTRACT FROM AUTHOR]

[Display omitted] • Dual-frequency multi-angle ultrasonic technology was suitable for tofu gel. • Cross-link degree and flavor of tofu gel were improved. • 40 + 20 kHz 30° group was the best analyzed by TOPSIS-entropy weight method. • The hardness and moisture content of tofu were improved. The effects of dual-frequency (40 + 20 kHz) and multi-angle ultrasound (0°, 30°, 45°) on the coagulation state, network structure, flavor and protein conformation of tofu gel were studied. The results showed that the gel flavor of 40 + 20 kHz 0° group was the best and fluorescence intensity was low. The gel flavor in the 40 + 20 kHz 30° group was better than the group without ultrasound, and hydrophobic interaction and disulfide bond content was the largest. Meanwhile, the degree of protein cross-link was increased. The gel in 40 + 20 kHz 45° group had tightly gel state, high thermal stability, but poor flavor. Combined with The Order Preference by Similarity to Ideal Solution (TOPSIS)-entropy weight method, the 40 + 20 kHz 30° group, was the best ultrasonic treatment of gel. It can change the interaction between proteins, promote protein cross-link, and form a uniform and dense gel network. Finally, the hardness and moisture content of finished tofu were increased significantly, and the quality was improved. [ABSTRACT FROM AUTHOR]

• Dual frequency sweep ultrasound decreased surface bacteria of freshly cut cauliflower. • Washing solutions ZA, TS, ET improved bacteria reduction and shelf-life. • Physical properties of washing solution effected ultrasound cavitation. This study investigated the effect of single and dual frequency ultrasound washing on freshly cut cauliflower, by pulsed and sweep frequency modes, with or without the addition of zinc acetate (ZA), tea saponin (TS) and ethanol (ET). Results showed that the surface microorganisms were efficiently decreased by sweep dual frequency ultrasound washing. Moreover, the use of 0.5% ZA, or 0.06% TS or 5% ET as washing solution improved the bacterial reduction efficiency. Reducing the interfacial tension, viscosity and contact angle of washing solution may strengthen ultrasound cavitation. Nearly 2.0 log CFU/g natural microorganisms were decreased, and shelf life was extended from 2 to 4–8 days under 4 °C. Physicochemical parameters of bioactive compounds content, enzyme activity, antioxidant ability, freshness were analyzed. Results showed that 0.5% ZA as washing solution of ultrasound washing was beneficial to the quality maintenance during storage period. [ABSTRACT FROM AUTHOR]

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 < 0.05) the release and diffusion of soluble SP across the cell wall into extraction solvent, causing enhanced observed rate constant (k) and diffusion-effective coefficient (D s) values over control. Moreover, dual frequency sonication (20/28 kHz) considerably increased oil holding efficacy and surface charge (by 21.07 and 32.15%, respectively), but reduced water holding efficacy and particle size (by 40.74 and 26.61%, respectively) relative to untreated sample (p < 0.05). Also, ultrasonicated SP displayed excellent solubility under varying pH (2−10), likened to the control (p < 0.05). Scanning electron microscopy (SEM) and atomic force microscopy (AFM) outcomes indicated that ultrasonicated SP showed irregular fragments, heterogenous/ disordered structure and small-sized particles, suggesting that sonication (notably 20/28 kHz) destroyed the cross-linkages among SP molecules. FT-IR spectroscopy exhibited that ultrasonication improved the content of β-sheet from 8.52–18.94% and random coil from 11.63–21.71%, whereas reductions in α-helix and β-turn were noticed, implying limited unfolding of SP structure and decreases in intermolecular interactions. Intrinsic fluorescence analysis revealed that dual frequency treatment was observed to be more efficient in altering the tertiary structure of SP reference to single frequency and control. 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 OH e) reference to control. The research outcomes may benefit food/ chemical industries in extraction and/or alteration of sunflower protein in new applications. • A new kinetic model for extraction of sunflower protein (SP) was developed. • Sonication (observably 20/28 kHz) increased the release and diffusion of soluble SP. • Ultrasonicated SP displayed higher solubility and oil holding efficacy than control. • AFM indicated the collapse of cross-linkages among SP molecules following sonication. • FTIR spectra exhibited notable changes in secondary structure of SP after sonication. [ABSTRACT FROM AUTHOR]

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. • Novel two-pot approach ultrasound-assisted DES pretreatment was demonstrated. • Effect of pretreatment factors on watermelon rind delignification was investigated. • Synergistic effect between ultrasonication and DES pretreatments was observed. • Synergistic effect correlated positively with severity of ultrasound pretreatment. • SEM and FTIR established the effectiveness of the combinative pretreatment methods. [ABSTRACT FROM AUTHOR]

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% H 2 O 2 (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. • Higher inactivation of microorganisms around 2.12-3.10 log CFU/g was obtained with combined ultrasound and sanitzers • Peracetic acid (40 mg/L) and 20/40 kHz caused ≥ 3-log CFU/g reduction in the natural microbiota. • The combined applications mitigated the senescence of the cherry tomato. [ABSTRACT FROM AUTHOR]