Current status and future trends of high-pressure processing in food industry

Compensation of high-pressure processing for the solubility of sodium-reduced chicken breast myosin with three anion types of potassium salts

The effect of high-pressure processing (200 MPa, 10 min) on the solubility of chicken breast myosin with 25% molar substitution of Na+ by 3 anion types of potassium salts (KCl, K-lactate, and K-citrate) was investigated. The results showed that the lower hydrophobic group and reactive sulfhydryl group of nonpressurized myosin with the replacement of organic K-lactate or K-citrate possibly contributed to the aggregation of myosin molecules compared with the KCl group and thus decreased the solubility of both. In the presence of lactate or citrate, the high-pressure processing caused an increase in the surface hydrophobicity and reactive sulfhydryl group, indicating the unfolding of myosin molecule. Meanwhile, the increased hydration state and the decreased apparent viscosity suggested the disruption of protein-protein interactions and the strengthening of myosin-water interactions in pressurized myosin, ultimately resulting in increased solubility of the pressurized myosin with both organic potassium salts. The compensation of high-pressure processing is interesting for the efficient selection of the anion type in developing sodium-reduced industrial meat products.

Understanding the Effects of High Pressure on Bacterial Spores Using Synchrotron Infrared Spectroscopy

Bacterial spores are extremely resistant life-forms that play an important role in food spoilage and foodborne disease. The return of spores to a vegetative cell state is a three-step process, these being activation, germination, and emergence. High-pressure (HP) processing is known to induce germination in part of the spore population and even to inactivate a high number of Bacillus spores when combined with other mild treatments such as the addition of nisin. The aim of the present work was to investigate the mechanisms involved in the sensitization of spores to nisin following HP treatment at ambient temperature or with moderate heating leading to a heterogeneous spore response. Bacillus subtilis spores were subjected to HP treatment at 500 MPa at 20 and 50°C. The physiological state of different subpopulations was characterized. Then Fourier transform infrared (FTIR) microspectroscopy coupled to a synchrotron infrared source was used to explore the heterogeneity of the biochemical signatures of the spores after the same HP treatments. Our results confirm that HP at 50°C induces the germination of a large proportion of the spore population. HP treatment at 20°C generated a subpopulation of ungerminated spores reversibly sensitized to the presence of nisin in their growth medium. Regarding infrared spectra of individual spores, spores treated by HP at 50°C and germinated spores had similar spectral signatures involving the same structural properties. However, after HP was performed at 20°C, two groups of spores were distinguished; one of these groups was clearly identified as germinated spores. The second group displayed a unique spectral signature, with shifts in the spectral bands corresponding to changes in membrane fluidity. Besides, spores spectra in the amide region could be divided into several groups close to spectral properties of dormant, germinated, or inactivated spores. The part of the spectra corresponding to α-helix and β-sheet-structures contribute mainly to the spectral variation between spores treated by HP at 20°C and other populations. These changes in the lipid and amide regions could be the signature of reversible changes linked to spore activation.

Quality and Safety of Fresh Chicken Fillets after High Pressure Processing: Survival of Indigenous Brochothrix thermosphacta and Inoculated Listeria monocytogenes

The effect of high-pressure processing (HPP) on Listeriamonocytogenes, the indigenous microbiota and the shelf-life of chicken fillets was evaluated. Chicken fillets were inoculated with different inocula (2, 4, and 6 log CFU/g) of a 4-strain cocktail of L. monocytogenes, vacuum-packed, processed or not with HPP (500 MPa/10 min) and stored at 4 °C and 12 °C. Total viable counts (TVC), L. monocytogenes, Pseudomonas spp., Brochothrix thermosphacta, lactic acid bacteria (LAB), Enterobacteriaceae and yeasts/molds were determined along with the pH and sensory analysis. Pulsed-field gel electrophoresis (PFGE) was used to monitor the succession of indigenous Brochothrix isolates and inoculated Listeria strains. The main spoilage microorganism of HPP-treated samples was B. thermosphacta detected after 3 days of storage. HPP decreased the inoculated Listeria population. For the low and medium inoculum case it was detected throughout the shelf-life at both temperatures in populations near to the detection limit or after enrichment. In the high inoculum case, the pathogen decreased ≥5-log cycles after HPP, while increased subsequently to 1.6 and 4.5 log CFU/g at 4 °C and 12 °C, respectively, by the end of the shelf-life. PFGE showed that Brochothrix isolates exhibited a significant diversity among control samples, whereas this was limited for the HPP-treated samples. The survival and distribution of different Listeria strains depended on the initial inoculum and storage temperature. In conclusion, HPP increased the shelf-life (for 5 and 4 days, at 4 °C and 12 °C, respectively) and enhanced the safety of chicken meat.

The combined effect of high pressure processing and dimethyl dicarbonate to inactivate foodborne pathogens in apple juice

Novel processing technologies can be used to improve both the microbiological safety and quality of food products. The application of high pressure processing (HPP) in combination with dimethyl dicarbonate (DMDC) represents a promising alternative to classical thermal technologies. This research work was undertaken to investigate the combined effect of HPP and DMDC, which was aimed at reaching over 5-log reduction in the reference pathogens Escherichia coli O157:H7, Salmonella enterica, and Listeria monocytogenes inoculated in apple juice. Different strains of each species were tested. The pressure (ranging from 100 to 600 MPa), dwell time (from 26 to 194 s), and DMDC (from 116 to 250 mg/L) were tested based on a central composite rotatable design. The dwell time, in the studied range, did not have a significant effect (p > 0.1) on the pathogens´ reduction. All treatments achieved a greater than 5-log reduction for E. coli O157:H7 and L. monocytogenes. The reductions for S. enterica were also greater than 5-log for almost all tested combinations. The results for S. enterica suggested that it is more resistant to HPP and DMDC compared with E. coli O157:H7 and L. monocytogenes. The findings of this study showed that DMDC at low concentrations can be added to apple juice to reduce the parameters conventionally applied in HPP. The combined use of HPP and DMDC was highly effective under the conditions of this study.

Emerging chemical and physical disinfection technologies of fruits and vegetables: a comprehensive review

With a growing demand for safe, nutritious, and fresh-like produce, a number of disinfection technologies have been developed. This review comprehensively examines the working principles and applications of several emerging disinfection technologies. The chemical treatments, including chlorine dioxide, ozone, electrolyzed water, essential oils, high-pressure carbon dioxide, and organic acids, have been improved as alternatives to traditional disinfection methods to meet current safety standards. Non-thermal physical treatments, such as UV-light, pulsed light, ionizing radiation, high hydrostatic pressure, cold plasma, and high-intensity ultrasound, have shown significant advantages in improving microbial safety and maintaining the desirable quality of produce. However, using these disinfection technologies alone may not meet the requirement of food safety and high product quality. Several hurdle technologies have been developed, which achieved synergistic effects to maximize lethality against microorganisms and minimize deterioration of produce quality. The review also identifies further research opportunities for the cost-effective commercialization of these technologies.

Modeling counterion partition in composite gels of BSA with gelatin following high pressure treatment

We examine the morphology of hydrogels made of bovine serum albumin and gelatin following high pressure processing at 300 MPa for 15 min at 10 and 80 °C. Emphasis is on the distribution of added calcium counterions between the polymeric phases seen in changes in the structural properties of the composite gel. Protocol includes thermal and HPP treatments, dynamic oscillation rheology, ESEM, and modeling from the "synthetic polymer approach" to rationalize results. Pressurization at 10 °C produced continuous gelatin networks with dispersed BSA inclusions whereas pressurization at 80 °C yielded an inverse dispersion of BSA as the continuous phase supporting liquid gelatin inclusions. Lewis and Nielsen equations were adapted to predict the counterion distribution between the polymeric phases that profoundly affected the structural properties of the pressurized gels. The concept of counterion partition (p_c) is introduced to the literature to follow the phase behavior of the composites in the presence of added calcium counterions.

Principles and recent applications of novel non-thermal processing technologies for the fish industry-a review

Thermal treatment is a traditional method for food processing, which can kill microorganisms but also lead to physicochemical and sensory quality damage, especially to temperature-sensitive foods. Nowadays consumers' increasing interest in microbial safety products with premium appearance, flavor, great nutritional value and extended shelf-life has promoted the development of emerging non-thermal food processing technologies as alternative or substitution to traditional thermal methods. Fish is an important and world-favored food but has a short shelf-life due to its extremely perishable characteristic, and the microbial spoilage and oxidative process happen rapidly just from the moment of capture, making it dependent heavily on post-harvest preservation. The applications of novel non-thermal food processing technologies, including high pressure processing (HPP), ultrasound (US), pulsed electric fields (PEF), pulsed light (PL), cold plasma (CP) and ozone can extend the shelf-life by microbial inactivation and also keep good sensory quality attributes of fish, which is of high interest for the fish industry. This review presents the principles, developments of emerging non-thermal food processing technologies, and also their applications in fish industry, with the main focus on microbial inactivation and sensory quality. The promising results showed great potential to keep microbial safety while maintaining organoleptic attributes of fish products. What's more, the strengths and weaknesses of these technologies are also discussed. The combination of different food processing technologies or with advanced packaging methods can improve antimicrobial efficacy while not significantly affect other quality properties under optimized treatment.

Hydrostatic High-Pressure Post-Processing of Specimens Fabricated by DLP, SLA, and FDM: An Alternative for the Sterilization of Polymer-Based Biomedical Devices

In this work, we assess the effects of sterilization in materials manufactured using additive manufacturing by employing a sterilization technique used in the food industry. To estimate the feasibility of the hydrostatic high-pressure (HHP) sterilization of biomedical devices, we have evaluated the mechanical properties of specimens produced by commercial 3D printers. Evaluations of the potential advantages and drawbacks of Fused Deposition Modeling (FDM), Digital Light Processing (DLP) technology, and Stereolithography (SLA) were considered for this study due to their widespread availability. Changes in mechanical properties due to the proposed sterilization technique were compared to values derived from the standardized autoclaving methodology. Enhancement of the mechanical properties of samples treated with Hydrostatic high-pressure processing enhanced mechanical properties, with a 30.30% increase in the tensile modulus and a 26.36% increase in the ultimate tensile strength. While traditional autoclaving was shown to systematically reduce the mechanical properties of the materials employed and damages and deformation on the surfaces were observed, HHP offered an alternative for sterilization without employing heat. These results suggest that while forgoing high-temperature for sanitization, HHP processing can be employed to take advantage of the flexibility of additive manufacturing technologies for manufacturing implants, instruments, and other devices.

Long-Term Storage of Vegetable Juices Treated by High Hydrostatic Pressure: Assurance of the Microbial Safety

Food business operators search for new, mild technologies, which extend the shelf life of product without changing the sensory and nutritional properties. High hydrostatic pressure (HHP) meets these requirements; however it also triggers sublethal injury of bacterial cells. Sublethal injuries could spoil the product during storage and potentially pose major public health concerns. This study aims to examine the changes of sublethally injured pathogens cells in two vegetable juices: carrot juice (pH 6.0-6.7) and beetroot juice (pH 4.0-4.2) that are induced by HHP (300-500 MPa). The possibilities of recovery of bacterial cells during 28 days of juices storage at two different temperatures (5°C and 25°C) were determined using plate count methods. During the entire period of storage of carrot juice at refrigerated temperature, the propagation and regeneration of L. innocua strains were observed. Storage at 25°C showed that the number of these bacteria drastically decreased between 14 and 21 days. The above phenomenon was not detected in E. coli case. There was no cells recovery during long-term refrigerated storage for all strains in beetroot juice. However, in some cases spoiling of this product intermittently occurred at 25°C storage temperature. This work demonstrates that carrot juice supports growth and regeneration of HHP-sublethally injured L. innocua, while beetroot juice can be classified as a safe product.

Influence of high-pressure processing on the generation of γ-aminobutyric acid and microbiological safety in coffee beans

BACKGROUND

The aim of this study was to investigate the influence of high-pressure processing (HPP) on γ-aminobutyric acid (GABA) content, glutamic acid (Glu) content, glutamate decarboxylase (GAD) activity, growth of Aspergillus fresenii, and accumulated ochratoxin A (OTA) content in coffee beans.

RESULTS

The results indicated that coffee beans subjected to HPP at pressures ≥50 MPa for 5 min increased GAD activity and promoted the conversion of Glu to GABA, and showed a significantly doubling of GABA content compared with unprocessed coffee beans. Additionally, investigation of the influence of HPP on A. fresenii growth on coffee beans showed that application ≥400 MPa reduced A. fresenii concentrations to <1 log. Furthermore, during a 50-day storage period, we observed that a processing pressure of 600 MPa completely inhibited A. fresenii growth, and on day 50 the OTA content of coffee beans subjected to processing pressures of 600 MPa was 0.0066 μg g^-1 , which was significantly lower than the OTA content of 0.1143 μg g^-1 in the control group.

CONCLUSION

This study shows that HPP treatment can simultaneously increase GABA content and inhibit the growth of A. fresenii, thereby effectively reducing the production and accumulation of OTA and maintaining the microbiological safety of coffee beans. © 2018 Society of Chemical Industry.

A New High Hydrostatic Pressure Process to Assure the Microbial Safety of Human Milk While Preserving the Biological Activity of Its Main Components

Background: The main process used to pasteurize human milk is the low-temperature, long-time Holder method. More recently, the high-temperature, short-time method has been investigated. Both processes lead to the appropriate inactivation of vegetative bacterial forms but are ineffective against bacterial spores. Research Aims/Questions: We aimed to accomplish two main objectives: inactivation of all pathogens, including spores; and preservation of the activity of milk components. Design/Methods: Recently, a novel high-hydrostatic pressure process has been developed by HPBioTECH. Using the same raw human milk samples, we compared the effects of this method with those of the Holder method on vegetative and spore forms of pathogens and on bioactive components (lipase activity, immunoproteins). Results: Two main microbial strains were selected: Staphylococcus aureus (as a reference for vegetative forms) and Bacillus cereus (as a reference for spores). Use of the high-hydrostatic pressure process led to microbial decontamination of 6 log for both S. aureus and B. cereus. Additionally, the bioactivity of the main components of human milk was preserved, with activities of lipase, α-lactalbumin, casein, lysozyme, lactoferrin, and sIgA of ~80, 96-99, 98-100, 95-100, 93-97, and 63-64%, respectively. Conclusions: Use of this novel high-hydrostatic pressure process to generate microbiologically safe human milk may provide important benefits for preterm infants, including improved assimilation of human milk (leading increased weight gain) and improved resistance to infections. Because 10% of all human milk collected is contaminated by B. cereus, use of this method will also prevent waste.

Effect of high-pressure processing on characteristics of flexible packaging for foods and beverages

High-pressure processing is an emerging food preservation technology that causes minimal product quality loss: Food packaged and high-pressure processed keep most of their nutritional qualities, in addition to extending their shelf life. However, the selection of packaging materials suitable for this technology becomes extremely important, since processing can cause changes in the visual aspects and in the physicochemical and mechanical properties of the materials, compromising the shelf life and safety of high-pressure processed foods somehow. Some studies have evaluated the effect of this technology on the properties and the migration and diffusion potential of intentional substances and of polymeric components in some flexible multilayer laminated packaging. Within this context, an important and relevant issue for industrial applications is knowing the possible effects of the parameters of high-pressure treatments, in low and high temperature, on the structure and morphology of materials that, in turn, can determine the relevant effects on the mechanical, barrier, and thermal properties and the migration and diffusion potential of intentional and non-intentional substances. Our study aims to make a literature review on the requirements of flexible packaging materials that can be used in high-pressure processing and the state of the art and the knowledge of the effects of different processing conditions on their properties.

Innovative processing techniques for altering the physicochemical properties of wholegrain brown rice (Oryza sativa L.) - opportunities for enhancing food quality and health attributes

Rice is a globally important staple consumed by billions of people, and recently there has been considerable interest in promoting the consumption of wholegrain brown rice (WBR) due to its obvious advantages over polished rice in metabolically protective activities. This work highlights the effects of innovative processing technologies on the quality and functional properties of WBR in comparison with traditional approaches; and it is aimed at establishing a quantitative and/or qualitative link between physicochemical changes and high-efficient processing methods. Compared with thermal treatments, applications of innovative nonthermal techniques, such as high hydrostatic pressure (HHP), pulsed electric fields (PEF), ultrasound and cold plasma, are not limited to modifying physicochemical properties of WBR grains, since improvements in nutritional and functional components as well as a reduction in anti-nutritional factors can also be achieved through inducing related biochemical transformation. Much information about processing methods and parameters which influence WBR quality changes has been obtained, but simultaneously achieving the product stabilization and functionality of processed WBR grains requires a comprehensive evaluation of all the quality changes induced by different processing procedures as well as quantitative insights into the relationship between the changes and processing variables.

Effect of high-pressure processing pretreatment on the physical properties and colour assessment of frozen European hake (Merluccius merluccius) during long term storage

Fish freshness is lost by autolytic degradation produced by endogenous enzymes. Frozen storage is one of the most used methods to preserve fish properties. However, protein denaturation has shown to be a major problem for frozen European hake (Merluccius merluccius), leading to texture losses and off-odour development. The aim of this work was to study the changes produced by high-pressure processing (HPP) before freezing on quality of frozen European hake stored at -21 °C for 12 months. The effect of HPP (150-450 MPa) on mechanical properties and expresible water was evaluated in raw and cooked fish samples. The effect on colour (L*, a* and b*) was assessed only in raw fish. Results showed that HPP before freezing is beneficial to maintain expresible water in good levels up to 6 months. The luminosity significantly increased with pressure level. Textural profile of raw samples showed that HPP increased hardness, adhesiveness and springiness of frozen hake. Cooked samples were also affected by HPP, being the best results obtained at 300 MPa for 6 months of frozen storage. Overall, results showed that HPP improves the quality of frozen hake.

Changes in the microbial communities in vacuum-packaged smoked bacon during storage

This study aimed to gain deeper insights into the microbiota composition and population dynamics, monitor the dominant bacterial populations and identify the specific spoilage microorganisms (SSOs) of vacuum-packed bacon during refrigerated storage using both culture-independent and dependent methods. High-throughout sequencing (HTS) showed that the microbial composition changed greatly with the prolongation of storage time. The diversity of microbiota was abundant at the initial stage then experienced a continuous decrease. Lactic acid bacteria (LAB) mainly Leuconostoc and Lactobacillus dominated the microbial population after seven days of storage. A total of 26 isolates were identified from different growth media using traditional cultivation isolation and identification method. Leuconostoc mesenteroides and Leuconostoc carnosum were the most prevalent species since day 15, while Lactobacillus sakei and Lactobacillus curvatus were only found on day 45, suggesting that they could be responsible for the spoilage of bacon. Serratia, Rahnella, Fusobacterium and Lactococcus underwent a dramatic increase at some point in individual batchs which may be considered as potential contributors to the spoilage.

Chemical Modifications of Lipids and Proteins by Nonthermal Food Processing Technologies

A range of nonthermal techniques have demonstrated process efficacy in ensuring product safety, extension of shelf life, and in general a retention of key quality attributes. However, various physical, chemical and biochemical effects of nonthermal techniques on macro and micro nutrients are evident, leading to both desirable and undesirable changes in food products. The objective of this review is to outline the effects of nonthermal techniques on food chemistry and the associated degradation mechanisms with the treatment of foods. Oxidation is one of the key mechanisms responsible for undesirable effects induced by nonthermal techniques. Degradation of key macromolecules largely depends on the processing conditions employed. Various extrinsic and intrinsic control parameters of high-pressure processing, pulsed electric field, ultrasound processing, and cold atmospheric plasma on chemistry of processed food are outlined. Proposed mechanisms and associated degradation of macromolecules, i.e., proteins, lipids, and bioactive molecules resulting in food quality changes are also discussed.

Comparison of high pressure and high temperature short time processing on quality of carambola juice during cold storage

This study validated high hydrostatic pressure processing (HPP) for achieving greater than 5-log reductions of Escherichia coli O157:H7 in carambola juice and determined shelf life of processed juice stored at 4 °C. Carambola juice processed at 600 MPa for 150 s was identified capable of achieving greater than 5.15-log reductions of E. coli O157:H7, and the quality was compared with that of high temperature short time (HTST)-pasteurized juice at 110 °C for 8.6 s. Aerobic, psychrotrophic, E. coli/coliform, and yeasts and moulds in the juice were reduced by HPP or HTST to levels below the minimum detection limit (< 1.0 log CFU/mL), and showed no outgrowth after refrigerated storage of 40 days. There were no significant differences in pH and titratable acidity between the untreated, HPP, and HTST juices. However, HTST treatment significantly changed the color of juice, while no significant difference was observed between the control and HPP samples. HPP and HTST treatments reduced the total soluble solids in the juice, but maintained higher sucrose, glucose, fructose, and total sugar contents than untreated juice. The total phenolic and ascorbic acid contents were higher in juice treated with HPP than untreated and HTST juice, but there was no significant difference in the flavonoid content. Aroma score analysis showed that HPP had no effect on aroma, maintaining the highest score during cold storage. The results of this study suggest that appropriate HPP conditions can achieve the same microbial safety as HTST, while maintaining the quality and extending the shelf life of carambola juice.

Mild high hydrostatic pressure pretreatments applied before soaking process to modulate wholegrain brown rice germination: An examination on embryo growth and physicochemical properties

This investigation aimed to examine the effects of a novel processing pattern, combining high hydrostatic pressure (HHP) with germination, on the embryo growth and physicochemical characteristics of wholegrain brown rice (WBR). WBR grains were firstly subjected to mild HHP stress (30-90 MPa/5 min) and then incubated at 37 °C for 52 h for obtaining germinated samples (GBR). The results showed that HHP shock resulted in a delayed embryo growth of WBR grains, maintaining acceptable sprouting rates ranging from 65% to 76% when germination was finished. The contents of gama-aminobutyric acid in GBR were greatly increased responding to HHP stress, showing pressure intensities dependent. Total digestible and resistant starch contents in samples stressed at 60/90 MPa were decreased, mainly associated with high pressure-induced amorphization as revealed by SEM imaging and FTIR, which promoted starch hydrolysis during germination. Besides, the levels of zinc and iron were influenced by HHP pretreatments due to the high pressure-mediated degradation behavior for phytic acids. The storability of HHP-stressed GBR grains was significantly enhanced through reducing free fatty acids formation and maintaining color stability during a storage testing. These results obtained from the current work demonstrated that mild HHP stress pretreatment prior to germination process could be used as a promising strategy to modulate certain physicochemical characteristics of WBR products.

Effect of Freezing, Thermal Pasteurization, and Hydrostatic Pressure on Fractionation and Folate Recovery in Egg Yolk

In this study, the impact of pasteurization and freezing of raw material, as performed at a commercial scale, on egg yolk fractionation and folate recovery was assessed. Freezing induced denaturation of the lipoproteins in egg yolk, which prevented further fractionation of the yolk. Thermal pasteurization of egg yolk at 61.1 °C for 3.5 min as well as high hydrostatic pressure (HHP) treatment (400 MPa for 5 min) did not change (p < 0.05) the composition of egg yolk or yolk fractions after their recovery by centrifugation. Expressed as dry matter, folate in pasteurized yolk was measured to be 599 μg/100 g, while its concentration reached 1969.7 μg/100 g for pasteurized granule and 1902.5 μg/100 g for HHP-treated granule. Folate was not detected in plasma, emphasizing the complete separation of yolk folate into granule. Further, we studied the effect of HHP on different dilutions of egg yolk, which were then fractionated. Egg yolk was diluted with water at different concentrations (0.1, 1.0, 10, 25, and 50%), HHP-treated at 400 MPa for 5 min, and centrifuged. Characterization of the compositions of the separated granule and plasma followed. Folate was stable under the HHP conditions used. However, HHP caused separation of folate from the yolk structure into water-soluble plasma. After HHP processing, the amount of folate detected in the plasma fraction was significantly (p < 0.05) higher (1434.9 μg/100 g) in the 25% diluted samples but was significantly (p < 0.05) lower in HHP-treated granule samples. Native sodium dodecyl sulfate-polyacrylamide gel electrophoresis results showed that phosvitin, α-livetin, and apovitellenin VIa were the proteins most resistant to HHP. This study confirms that dilution of egg yolk before HHP treatment can significantly (p < 0.05) change the composition of granule and plasma fractions after centrifugal fractionation of egg yolk.

Effect of high-pressure processing and thermal pasteurization on overall quality parameters of white grape juice

BACKGROUND

The aim of this study was to investigate the microbial levels, physicochemical and antioxidant properties and polyphenol oxidase (PPO) and peroxidase (POD) activities as well as to conduct a sensory analysis of white grape juice treated with high-pressure processing (HPP) and thermal pasteurization (TP), over a period of 20 days of refrigerated storage.

RESULTS

HPP treatment of 600 MPa and TP significantly reduced aerobic bacteria, coliform and yeast/mold counts. At day 20 of storage, HPP-600 juice displayed no significant differences compared with fresh juice in terms of physicochemical properties such as titratable acidity, pH and soluble solids, and retained less than 50% PPO and POD activities. Although significant differences were observed in the color, antioxidant contents and antioxidant capacity of HPP-treated juice, the extent of these differences was substantially lower than that in TP-treated juice, indicating that HPP treatment can better retain the quality of grape juice. Sensory testing showed no significant difference between HPP-treated juice and fresh juice, while TP reduced the acceptance of grape juice.

CONCLUSION

This study shows that HPP treatment maintained the overall quality parameters of white grape juice, thus effectively extending the shelf life during refrigerated storage. © 2016 Society of Chemical Industry.