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The aim of this study was to evaluate the effects of high pressure processing (HPP; 550 MPa/10 min) and high temperature short time (HTST; 110 °C/8.6 s) on microorganism, ascorbic acid, total phenols, antioxidant capacity, color, enzyme activity, and rheological behavior in red grapefruit juice during 30 days of storage at 4 °C. After HPP, the total plate count (TPC) and yeast and molds (Y & M) in red grapefruit juice were significantly decreased by 4.83 and 4.15 log cycles and showed to be microbiologically safe during storage. The activity of pectin methylesterase (PME) and peroxidase (POD) was only inactivated by 22.5 % and increased by 10.4 % by HPP, but completely inactivated by HTST. For all the other quality properties (such as total phenols, ascorbic acid, antioxidant capacity, color) except cloud stability studied in this article, their retention was significantly better in the HPP-treated samples than in the HTST-treated samples during storage, which were closer to natural grapefruit juice. A longer shelf life was observed in HPP-treated grapefruit juice compared to HTST-treated ones.

The combined effect of high pressure processing and temperature on aminopeptidases activity of lactic acid bacteria used as starter cultures in brined cheese manufacturing, in order to find the optimum process conditions for acceleration of the significant long-duration cheese ripening step, was investigated. The effect of high hydrostatic pressure (HP) (100–450 MPa) combined with temperature (20–40 °C) on the activity of five aminopeptidases (PepN, PepX, PepY, PepC, and PepA) of Streptococcus thermophilus ACA-DC 0022 and Lactococcus lactis ACA-DC 0049, used as the starter culture for white Greek brine cheese ( feta ) production, was studied. S. thermophilus aminopeptidases PepN, PepX, PepA, and PepC were activated at pressures up to 200 MPa, and all studied temperatures (20–40 °C), while for L. lactis , PepN, X, and Y were activated at pressures up to 300 MPa and temperatures up to 30 °C and PepA at the same temperature range but milder pressures (up to 200 MPa). For L. lactis , PepC an increase in activity was observed at all studied pressures but only at 20 °C. A multi-parameter equation was used for predicting the activation of all aminopeptidases in the pressure and temperature domain. Overall, processing at 200 MPa and 20 °C may be selected as the optimum conditions for maximum activation of all aminopeptidases of both S. thermophilus ACA-DC 0022 and L. lactis ACA-DC 0049. A 20-min treatment at these conditions leads to an average threefold increase in activity which could lead to better and faster maturation of white cheese.

High-pressure (HP) treatment could lead to several advantages when applied to fish and seafood since it would affect the extension of the shelf life of this highly perishable food. In this regard, this study aimed to evaluate the effect of high-pressure treatment (500 MPa for 2 min at a temperature of 4 °C) on changes in quality on two different kinds of fresh fish fillets (Salmo salar and Pleuronectes platessa). Specifically, physico-chemical (VOCs, untargeted metabolomics spectra, pH and color), microbiological (Enterobacteriaceae, Pseudomonas spp., mesophilic and psychrotrophic bacteria) and sensory traits were evaluated at different days of refrigerated storage. From the results obtained, it is possible to state that the high pressure significantly (p ≤ 0.05) reduced microbial growth for each investigated microorganism. Regarding the colorimetric coordinates, no remarkable effects on a* and b* indices were found, while a significant effect (p = 0.01) was observed on the colorimetric index L*, making the HP-treated samples lighter than their respective controls. The sensory analysis showed that for the odor attribute, the HP treatment seems to have had a stabilizing action during shelf-life. Moreover, the treated samples obtained a better score than the respective controls (p ≤ 0.05). With regards to texture and appearance attributes, the treatment seems to have had a significant (p ≤ 0.05) effect, making the treated samples more compact and opaque than controls, therefore resulting in the loss of the characteristics of raw fish for the treated samples. Moreover, from a chemical point of view, HP treatment prevents the development of volatile sulfides and delays the formation of histamine (p ≤ 0.05). Very interestingly, the metabolomic approach revealed novel dipeptide markers for the HP procedure.

The objective of the present work was to assess the effectiveness of high‐pressure (HP) treatment on the enzymatic hydrolysis of lentil protein (LP) in order to improve functionality and antioxidant activity of hydrolysates. LP dispersions were subjected to HP treatment in the selected pressure levels (300, 450, and 600 MPa for 15 min) prior to hydrolysis with alcalase (0.5% and 1%, w/w). The postprocess samples were analyzed to assess the impact of pressure treatment on denaturation, the degree of hydrolysis (DH), and antioxidant activity of hydrolysate. HP treatment improved the %DH of the LPI (p ≤ 0.05). The HP‐assisted alcalase hydrolysis imparted significant changes on the secondary structure of protein with a shift of amide I and amide II bands. The hydrolysis of LP was further confirmed by a significant drop on the enthalpy (ΔH) values in the DSC endothermic peaks and decreasing the steady shear viscosity. The pressurized protein hydrolysates attained an improvement in the foaming properties (≈1.5 times) and antioxidant activities (≈2 times) than the control hydrolysates. However, a detrimental effect was pronounced on the emulsifying activity and stability index, foam stability, and water holding capacity. These results could be useful for food industries to develop products using hydrolysates as protein supplements.

This study investigated the impact of dynamic high-pressure (DHP) treatment on the ability of whey protein isolate (WPI) to form associative complexes with pectin and to form aggregate particles after their subsequent heat treatment. Light scattering showed that DHP treatments disrupted preexisting WPI aggregates and assembled pectin chains. Complexes formed from WPI/pectin mixtures at pH 4.5 were an order of magnitude smaller when formed after DHP treatment, regardless of the degree of esterification. WPI/pectin complexes formed after DHP treatment were more stable against subsequent pH neutralization than complexes formed without DHP treatment, and WPI/high-methoxyl pectin (HMP) complexes had greater stability than WPI/low-methoxyl pectin (LMP) complexes. WPI/pectin particles prepared by thermal treatment of complexes at pH 4.5 were also smaller when prepared after DHP treatment. WPI/HMP particles were stable to subsequent pH neutralization, while WPI/LMP particles became larger after neutralization.

Microbial load, protein oxidation, myofibrillar protein changes and quality characteristics (meat color and water retentiveness including centrifugal loss (CeL) and water-holding capacity (WHC)) of post-rigor tan mutton exposed to different high-pressure treatments (200 MPa/500 MPa for 15 min at 18°C) during chilled storage for 7 days (4°C) were evaluated. High-pressure applications of 200 MPa and 500 MPa significantly reduced the number of Total Viable Counts (TVC) during storage (P < 0.05), but excessive pressure treatment (500 MPa) also resulted in a significant increase in protein oxidation and decrease in water retentiveness (P < 0.05), accompanied by deterioration of meat color. 200 MPa treatment also caused adverse effects on the quality of processed meat at the later stage of storage (3-7 d) similar to 500 MPa high pressure, but the initial application of 200 MPa pressure resulted in no significant differences in meat color and retentiveness from the untreated (P > 0.05) and better texture characteristics than untreated samples. ANOVA with Partial Least Squares Regression (APLSR) confirmed the relationshipS between these variations in quality characteristics induced by high-pressure treatments and protein oxidation and key myofibrillar skeleton proteins.

The quinoa flour (QF) dispersions (flour/water = 1:2) were subjected to high-pressure treatment (300, 450 and 600 MPa for 15 min) at ambient temperature, and thereafter, assessed for the structural changes using rheometry, calorimetry, microscopy, and diffractometry. The pressurization influenced the hydration property of QF significantly. The quinoa starch gelatinized completely by melting the amylopectin crystallites at 600 MPa as confirmed by the thermal, rheological and diffractometric studies. The mechanical rigidity of the pressure-induced gel improved considerably by increasing the pressure level. Further heating to the HP-treated QF dispersions (< 600 MPa) improved the mechanical rigidity significantly. The protein denaturation peaks remained unaffected by the pressure treatment. The antioxidant activity of QF increased at 450 MPa. The results obtained in this research could be useful for the development of quinoa-based food product under high-pressure.

γ-aminobutyric acid (GABA) is the chief inhibitory neurotransmitter in the central nervous system and of substantial physiological significance to mammals. The GABA content of plants is generally low; however, it increases significantly when plants encounter stress. The present study investigates the effects of flooding stress and high-pressure processing on GABA content enrichment in the vegetable soybean (Glycine max Merr.) cultivar Kaohsiung No. 9 and potential mechanisms. Results indicate that flooding stress increased the GABA content of vegetable soybean kernels, with the possible mechanism involving the upregulation of glutamic acid decarboxylase 5 (GAD5) and aminoaldehyde dehydrogenase (AMADH) and downregulation of succinate semialdehyde dehydrogenase (SSADH). High-pressure treatment increased the GABA content through increased GAD activity. A specific combination of flooding stress, high-pressure treatment, and storage treatment enhanced vegetable soybean GABA content up to 696.6 ± 65.7 mg/100 g. Flooding treatment prior to harvesting did not cause differences in consumption quality. These results show that flooding stress and high pressure treatment can increase GABA content and enhance the functional value of the vegetable soybean cultivar Kaohsiung No. 9.

This study was carried out to investigate the effect of high pressure-low temperature (HPLT) treatment on physicochemical properties and nutrients in milk. The milk was treated at 200MPa and −4°C for 10, 20, and 30min. Protease and lipase activities of HPLT-treated milk were highly inactivated compared with that of raw milk. Among time treatments, the 30-min treatment showed the lowest activities compared with others. Absorbance of thiobarbituric acid increased with time in HLPT-treated milks; however, no difference was observed between the raw milk and milk treated for 10min. The concentrations of short-chain fatty acids except C4 in HPLT-treated milks increased with time. The total free amino acids in HPLT-treated milks were greater than that of the raw milk for the 30-min treatment. l-Ascorbic acid, niacin, and riboflavin in HPLT-treated milks were significantly lower compared with concentrations in raw milk. For color, the L-value of HPLT-treated milks was significantly lower than that of the raw milk; however, there was no difference in the a-value for 10min and in the b-value at 20min between the raw milk and the HPLT-treated milks.

Edible flowers are increasing worldwide because they can improve the appearance, taste, and aesthetic value of food, aspects that the consumer appreciates. However, some of these are highly perishable and have a short shelf-life. To overcome these problems, high hydrostatic pressure (HHP) food processing might be applied, allowing producing high-quality food with enhanced safety and increased shelf-life. The application of HHP to vegetables has been extensively discussed and is already an industrial reality, but information on edible flowers is scarce and incomplete. Thus, in order to summarize the current knowledge on potential applications of HHP treatment in edible flowers and to determine the effect of this treatment on physical (e.g., color and texture) and nutritional characteristics as well as on microbial and enzymatic inactivation, a literature review was performed. It was stated that broccoli and cauliflower (inflorescences, usually not considered by consumers as flowers) have been the most studied, existing few information for other edible flowers. Thus, much more works are needed to better understand the effect and mechanisms behind HHP, and to define the adequate technological conditions for each flower.