Impact of ultra high pressure homogenization on pectin methylesterase activity and microbial characteristics of orange juice: A comparative study against conventional heat pasteurization

Thermaland non-thermal pasteurization of citrus fruits: A bibliometrics analysis

Thermal and non-thermal pasteurization (TNP) process of food is not new to food technology, disparities in the merits and demerits of the two pasteurizations necessitate their uses concurrently. Bibliometric analysis of the subject matter is expedient to analyses of database for published publications. Especially to provide times, state-of-the art innovations and prospects of the techniques. In addressing these lacunas, we utilized VOSview visualization to establish connections among crucial elements within a dataset of 495 research publications gathered from Web of Science. This approach facilitated the identification of links and collaboration networks among key factors in the research landscape. Analysis of publications indicate thermal pasteurization is an age long practices, while non-thermal pasteurization is gaining more acceptance. This study exposed ranking differences in scholar's collaboration, citations of scholars, impactful institution and most published countries. United State, China, United Kingdom have largest publications of research in TNP among the top 10 countries. Coupling network and Sankey illustration showed new area of research where new researchers and scholars can begin new phase of findings.

High pressure homogenization applied to fruit juices: Effects on microbial inactivation and on maintenance of bioactive components

High-pressure homogenization (HPH) is a non-thermal technology widely studied to replace, partially or in total, the conventional thermal preservation processes used in the food industry, thus minimizing undesirable changes in the nutritional and sensory characteristics of liquid products. The main effect of HPH is the size reduction of dispersed particles thus affecting physical stability of the products, despite also inactivating microorganisms, preserving bioactive compounds, and maintaining sensory characteristics. During the process, the fluid is driven under high-pressure through a micrometric gap inside the valve. Phenomena including cavitation, shear and turbulence are responsible for the changes in the fluid. From this perspective, the present paper reviews the effects of HPH on the inactivation of microorganisms and preservation of bioactive compounds of fruit juices treated with this technology. The juice matrices reported were apple, apricot, banana, blackberry, carrot, kiwifruit, mandarin, mango, orange, peach, pomegranate, rosehip, strawberry and tomato. The paper elucidates the potential application of HPH to fruit juice processing aiming at producing safe products with high nutritional and sensory quality.

Effect of HHP and UHPH High-Pressure Techniques on the Extraction and Stability of Grape and Other Fruit Anthocyanins

The use of high-pressure technologies is a hot topic in food science because of the potential for a gentle process in which spoilage and pathogenic microorganisms can be eliminated; these technologies also have effects on the extraction, preservation, and modification of some constituents. Whole grapes or bunches can be processed by High Hydrostatic Pressure (HHP), which causes poration of the skin cell walls and rapid diffusion of the anthocyanins into the pulp and seeds in a short treatment time (2-10 min), improving maceration. Grape juice with colloidal skin particles of less than 500 µm processed by Ultra-High Pressure Homogenization (UHPH) is nano-fragmented with high anthocyanin release. Anthocyanins can be rapidly extracted from skins using HHP and cell fragments using UHPH, releasing them and facilitating their diffusion into the liquid quickly. HHP and UHPH techniques are gentle and protective of sensitive molecules such as phenols, terpenes, and vitamins. Both techniques are non-thermal technologies with mild temperatures and residence times. Moreover, UHPH produces an intense inactivation of oxidative enzymes (PPOs), thus preserving the antioxidant activity of grape juices. Both technologies can be applied to juices or concentrates; in addition, HHP can be applied to grapes or bunches. This review provides detailed information on the main features of these novel techniques, their current status in anthocyanin extraction, and their effects on stability and process sustainability.

Non-thermal emerging processing Technologies: Mitigation of microorganisms and mycotoxins, sensory and nutritional properties maintenance in clean label fruit juices

The increase in the fruit juice consumption and the interest in clean label products boosted the development and evaluation of new processing technologies. The impact of some emerging non-thermal technologies in food safety and sensory properties has been evaluated. The main technologies applied in the studies are ultrasound, high pressure, supercritical carbon dioxide, ultraviolet, pulsed electric field, cold plasma, ozone and pulsed light. Since there is no single technique that presents high potential for all the evaluated requirements (food safety, sensory, nutritional and the feasibility of implementation in the industry), the search for new technologies to overcome the limitations is fundamental. The high pressure seems to be the most promising technology regarding all the aspects mentioned. Some of the outstanding results are 5 log reduction of E. coli, Listeria and Salmonella, 98.2% of polyphenol oxidase inactivation and 96% PME reduction. However its cost can be a limitation for industrial implementation. The combination of pulsed light and ultrasound could overcome this limitation and provide higher quality fruit juices. The combination was able to achieve 5.8-6.4 log cycles reduction of S. Cerevisiae, and pulsed light is able to obtain PME inactivation around 90%, 61.0 % more antioxidants, 38.8% more phenolics and 68.2% more vitamin C comparing to conventional processing, and similar sensory scores after 45 days at 4 °C comparing to fresh fruit juice. This review aims to update the information related to the application of non-thermal technologies in the fruit juice processing through systematic and updated data to assist in industrial implementation strategies.

Effects and impacts of technical processing units on the nutrients and functional components of fruit and vegetable juice

Fruit and vegetable juice (FVJ) has become a favorite beverage for all age groups because of its excellent sensory and nutritional qualities. FVJ has a series of health benefits such as antioxidant, anti-obesity, anti-inflammatory, anti-microbial and anti-cancer. Except for raw materials selection, processing technology and packaging and storage also play a vital role in the nutrition and functional components of FVJ. This review systematically reviews the important research results on the relationship between FVJ processing and its nutrition and function in the past 10 years. Based on the brief elucidation of the nutrition and health benefits of FVJ and the unit operation involved in the production process, the influence of a series of key technology units, including pretreatment, clarification, homogenization, concentration, sterilization, drying, fermentation and packaging and storage, on the nutritional function of FVJ was systematically expounded. This contribution provides an update on the impacts of technical processing units on the nutrients and functional components of FVJ and new perspectives for future studies.

Effect of Ultra-High-Pressure Homogenization Processing on the Microbiological, Physicochemical, and Sensory Characteristics of Fish Broth

The effect of ultra-high-pressure homogenization (UHPH) treatments at 300 MPa at inlet temperatures (T_i) between 45 and 75 °C on the microbiological, physical, and sensorial characteristics of fish broth was evaluated. Before the application of UHPH treatments, different fish broth formulations were tested, selecting the formula with the best organoleptic and nutritional characteristics and the lowest cost, containing 45% monkfish heads and rock fish in the same proportion. The microbiological shelf-life of fish broth during cold storage at 4 and 8 °C was extended by a minimum of 20 days by applying UHPH treatments at inlet temperatures (T_i) between 45 and 65 °C. Fish broth UHPH-treated at T_i = 75 °C was microbiologically sterile during storage at 4 °C, 8 °C, and room temperature. Fish broth UHPH-treated was physically stable, significantly reducing the particle size. Color showed higher luminosity and lower yellowness as the inlet temperature increased. In fish broth UHPH-treated at T_i = 75 °C, selected for its microbiological stability, no differences were observed in the nutritional composition, antioxidant activity, and sensorial perception compared to untreated fish broth. Hence, UHPH treatments showed to be an alternative to preserving fish broth with an improved microbiological shelf-life and good sensorial characteristics.

How to comprehensively improve juice quality: a review of the impacts of sterilization technology on the overall quality of fruit and vegetable juices in 2010-2021, an updated overview and current issues

Fruit and vegetable juices (FVJ) are rich in nutrients, so they easily breed bacteria, which cause microbial pollution and rapid deterioration of their quality and safety. Sterilization is an important operation in FVJ processing. However, regardless of whether thermal sterilization or non-thermal sterilization is used, the effect and its impact on the overall quality of FVJ are strongly dependent on the processing parameters, microbial species, and FVJ matrix. Therefore, for different types of FVJ, an understanding of the impacts that different sterilization technologies have on the overall quality of the juice is important in designing and optimizing technical parameters to produce value-added products. This article provides an overview of the application of thermal and non-thermal technique in the field of FVJ processing over the past 10 years. The operating principle and effects of various technologies on the inactivation of microorganisms and enzymes, nutritional and functional characteristics, physicochemical properties, and sensory quality of a wide range of FVJ are comprehensively discussed. The application of different combinations of hurdle technology in the field of FVJ sterilization processing are also discussed in detail. Additionally, the advantages, limitations, and current application prospects of different sterilization technologies are summarized.

Role of pectin characteristics in orange juice stabilization: Effect of high-pressure processing in combination with centrifugation pretreatments

"High-pressure processing (HPP) plus" combined technologies are applied to overcome the limitation of single HPP and to produce juices with more stable quality during storage. This research explored the potential of HPP in combination with centrifugation to produce cloud stable orange juice during refrigerated storage. The results indicated that HPP combined processing technology significantly improved the cloud stability of orange juice, which was related to removed large particles, reduced viscosity, decreased protein contents, and inactivated pectin methylesterase activity induced by centrifugation (P < 0.05). Besides, chelator solubilized pectin (CSP) decreased but water solubilized pectin (WSP) maintained in the juice after centrifugation. During storage, the conversion of pectin fraction from WSP to CSP, resulting in sedimentation appeared in centrifugation treated orange juice when stored for 28 days. In general, pectin characteristics changes and pectin fractions conversion were the main driving forces affecting cloud stability of orange juice pasteurized by HPP in combination with centrifugation and during chilled storage.

Modelling and optimization of high-pressure homogenization of not-from-concentrate juice: Achieving better juice quality using sustainable production

The present work optimized high-pressure homogenization (HPH) parameters for not-from-concentrate combined peach and carrot juices, based on a two-step comprehensive model using factor analysis and analytic hierarchy process methods. Treating combined juice with pressures over 200 MPa retained more amounts of the bioactive compounds (carotenoids and polyphenols) than non-homogenization. Nutrition-oriented optimization, with higher judgement weight on nutritional properties, and sense-oriented optimization, with higher weight on sensory properties, were set up. Combined juice (250 MPa, 1 pass and 25 °C) had the best quality, based on the nutrition- and sense-oriented models. Back propagation neural network (BPNN) models could predict antioxidant capacities of the combined juice with greater accuracy compared with stepwise linear regression. The relative errors of BPNN prediction model were ≤ 5%.

Comparison of the Effect of Hydrostatic and Dynamic High Pressure Processing on the Enzymatic Activity and Physicochemical Quality Attributes of 'Ataulfo' Mango Nectar

The effects of hydrostatic (HHP) and dynamic (HPH) high-pressure treatments on the activity of pectin methylesterase (PME) and polyphenol oxidase (PPO) as well as the physicochemical quality attributes of ‘Ataulfo’ mango nectar were assessed. HHP reduced PME relative activity by 28% at 100 MPa for 5 min but increased PPO activity almost five-fold. Contrarily, HPH did not affect PME activity, but PPO was effectively reduced to 10% of residual activity at 300 MPa and at three passes. Color parameters (CIEL*a*b*), °hue, and chroma were differently affected by each type of high-pressure processing technology. The viscosity and fluid behavior were not affected by HHP, however, HPH changed the apparent viscosity at low dynamic pressure levels (100 MPa with one and three passes). The viscosity decreased at high shear rates in nectar samples, showing a shear-thinning effect. The results highlight how different effects can be achieved with each high-pressure technology; thus, selecting the most appropriate system for processing and preserving liquid foods like fruit beverages is recommended.

High pressure homogenization with a cooling circulating system: The effect on physiochemical and rheological properties, enzymes, and carotenoid profile of carrot juice

The influence of high pressure homogenization (HPH) at 100-150 MPa performed by multiple passes below 35 °C on carrot juice quality and stability was studied. The highest reduction in microorganisms (by 2.47 log) was noted at 150 MPa with 5 passes of the juice through the homogenizer. The PPO and POD's residual activity increased after HPH; PG was at the same level, while PME activity increased or decreased depending on the process parameters used. HPH treatment resulted in a decrease in the apparent dynamic viscosity, turbidity and colour parameters. Five passes at 150 MPa caused an increase in the carotenoid content, especially 9-Z-β-carotene (by 154%) while the TPC did not change significantly. Carrot juice treatment at 150 MPa with 5 passes may extend its shelf-life by 3 days when stored at 4 °C.

An overview of different homogenizers, their working mechanisms and impact on processing of fruits and vegetables

Fruits and vegetables (F&V) are the second highest recommended foods, rich in antioxidants, vitamins and minerals, vital for building immunity against chronic diseases. F&V processing involves particle size reduction, for which different types of homogenizers, categorized as mechanical homogenizers, pressure homogenizers and ultrasonic homogenizers are used. The review discusses different types of homogenizers, their working mechanism, and application in F&V processing. Among mechanical homogenizers, knife mills are used for primary size reduction, ball mills for the micronization of dried F&V and rotor-stator homogenizers for emulsification. Use of the ultrasonic homogenizer is limited to extraction of bioactive compounds or as a pre-treatment for dehydration of F&V. High-pressure homogenizers are most widely used and reported due to the synergistic effect of homogenization and temperature increase, resulting in longer shelf-life and better physicochemical properties of the product. Additionally, the review also explains the effect of homogenization on the physicochemical, sensory and nutraceutical properties of the product.

Effects of High-Pressure Homogenization on Pectin Structure and Cloud Stability of Not-From-Concentrate Orange Juice

Not-from-concentrate (NFC) juice is popular with consumers due to its similarity to fresh fruit juice in taste, flavor, and beneficial nutrients. As a commonly used technology in fruit juice production, high-pressure homogenization (HPH) can enhance the commercial value of juice by improving the color, flavor, taste, and nutrient contents. In this study, the effects of HPH on the pectin structural properties and stability of NFC orange juice were investigated. The correlations between HPH-induced changes in the structure of pectin and the stability of orange juice were revealed. Compared with non-homogenized orange juice, HPH increased the galacturonic acid (GalA) content and the linearity of pectin, while decreasing the molecular weight (Mw), pectin branching, and rhamnogalacturonan (RG) contribution, and cracks and pores of different sizes formed on the surface of pectin, implying depolymerization. Meanwhile, with increasing pressure and number homogenization of passes, HPH effectively improved the stability of NFC orange juice. HPH can effectively prevent the stratification of orange juice, thereby promoting consumer acceptance and endowing a higher commercial value. The improvement of the stability of NFC orange juice by HPH was related to the structural properties of pectin. Turbidity was significantly (P < 0.01) positively correlated with GalA and pectin linearity, but was significantly (P < 0.01) negatively correlated with Mw, RG contribution, and pectin branching. Modification of pectin structure can improve the stability of NFC orange juice. In this work, the relationship between the pectin structure and stability of NFC orange juice is elucidated, providing a path toward improving consumer acceptance and enhancing the palatability and nutritional and functional qualities of orange juice. Manufacturers can use this relationship to modify pectin directionally and produce high-quality NFC orange juice beverages.

Continuous High-pressure Cooling-Assisted Homogenization Process for Stabilization of Apple Juice

The effect of high-pressure homogenization (HPH) at 100–200 MPa (with up to 5 passes) on the quality and storage stability of apple juice was investigated. The microbiological quality, polyphenol oxidase (PPO), peroxidase (POD), polygalacturonase (PG) and pectinmethylesterase (PME) activity, particle size distribution (PSD), apparent viscosity, turbidity, concentration of vitamin C, individual polyphenols and their total content (TPC), antioxidant activity, and colour of fresh, HPH-treated apple juice were all evaluated. The highest reduction in microorganisms (1.4 log) and oxidoreductase activity (~20%) was observed at 200 MPa, while hydrolases did not change significantly. HPH led to significant disintegration of the tissue and a decrease in viscosity. Vitamin C decreased by 62%, while TPC increased by 20% after HPH. Significant correlations were observed between antioxidant activity, TPC, and individual polyphenols. Chlorogenic, ferulic, and gallic acid were most stable at 200 MPa. The optimal shelf-life of the juice was estimated as 7 days.

Use of UHPH to Obtain Juices With Better Nutritional Quality and Healthier Wines With Low Levels of SO2

Ultra-high pressure homogenization (UHPH) is a high pressure technique in which a fluid is pressurized by pumping at higher than 200 MPa and instantaneously depressurized at atmospheric pressure across a special valve. The full process takes <0.2 s and the in-valve time is <0.02 s. In the valve, extremely intense impacts and shear forces produce the nanofragmentation of biological tissue at a range of 100-300 nm. The antimicrobial effect is highly effective, reaching easily inactivation levels higher than 6-log cycles even at low in-valve temperatures. At in-valve temperatures of 140-150°C (0.02 s) the destruction of thermoresistant spores is possible. Even when the temperature in-valve can be elevated (70-150°C), it can be considered a gentle technology because of the tremendously short processing time. It is easy to get outlet temperatures after valve of 20-25°C by the expansion and assisted by heat exchangers. Thermal markers as hydroxymethylfurfural (HMF) are not formed, nor are deleterious effects observed in sensitive compounds as terpenes or anthocyanins, probably because of the low effect in covalent bonds of small molecules of the high-pressure techniques compared with thermal technologies. Additionally, intense inactivation of oxidative enzymes is observed, therefore protecting the sensory and nutritional quality of fruit juices and avoiding or reducing the use of antioxidants as sulphites. UHPH can be consider a powerful and highly effective continuous and sterilizing technology without thermal repercussions, able to keep fresh juices with most of their initial sensory and nutritional quality and allowing high-quality and natural fermented derivatives as wine.

Effects of kiwi's pectin methylesterase inhibitor, nanomilling and pasteurization on orange juice quality

Endogenous pectin methylesterase (PME) is the enzyme responsible for phase separation and cloud loss in orange juice (OJ) manufacturing. The effect of kiwi's PME inhibitor (PMEI), nanomilling, and pasteurization on OJ quality was evaluated. The microbial quality, PME activity, OJ separation, pH, ascorbic acid content and the sensory characteristics of the juice were followed during 5 weeks storage (4°C). PMEI as freeze-dried kiwi powder (0.3%, w/w) succeeded in inhibiting 89.3% of the OJ PME without affecting the microbial and the sensory quality. Nanomilling of OJ pulp, to prepare nano-particles OJ (NPOJ), reduced the initial microbial load by 1.65 and 1.83 log for psychrotrophs and yeasts and molds, respectively; significantly (p < .05) inactivated 40.9% of the residual PME activity and the juice separation was significantly reduced by 48.3% (after 14 days of storage). Nanomilling exhibited no effect on OJ pH, but slight (p < .05) decrease in ascorbic acid content was noted. The combination of PMEI with NPOJ resulted in improved OJ stability with reduced separation to 36.4% of that of control. Such combination also allowed to use a lower pasteurization temperature at lower exposure time (60°C/5 min) needed to obtain new NPOJ with comparable high quality as fresh OJ and which has a shelf life of 3 weeks (4°C).

Microbial, nutritional, and organoleptic quality of pomegranate juice following high-pressure homogenization and low-temperature pasteurization

This study investigated the effects of high-pressure homogenization (HPH) on microbial, nutritional, and organoleptic qualities of pomegranate juice. Juices subjected to HPH at 100 and 150 MPa were compared to those subjected to thermal pasteurization at 55, 65, and 75 °C for 15 s, and to combined treatments. Physicochemical properties of pomegranate juices, such as color, pH, acidity, and total soluble solids, were marginally affected by either treatment. Significant microbial inactivation for the juices inoculated with Escherichia coli and yeast was achieved during 28 days of shelf life by HPH at 150 MPa, followed by thermal treatment at 65 °C. There was no significant difference in ascorbic acid levels between the treated and fresh juice. Total polyphenol content and antioxidant activity were measured to be higher in case of both treatment methods. Analyzing treated HPH samples with electronic tongue and nose showed similar flavor profiles to the fresh juice. PRACTICAL APPLICATION: The work shows the benefits of using the advanced high-pressure homogenization (HPH) compared to common thermal treatment used today in fruit juice pasteurization. HPH is capable to provide sufficient reduction in microbial with better nutritional and organoleptic quality. In this manuscript, we showed the potential of HPH as alternative method for pasteurization on a highly healthy fruit like pomegranate. The work describes the advantages in HPH process through comprehensive analysis for nutritional, microbial, and sensorial quality.

Two Nonthermal Technologies for Food Safety and Quality-Ultrasound and High Pressure Homogenization: Effects on Microorganisms, Advances, and Possibilities: A Review

Some nonthermal technologies have gained special interest as alternative approaches to thermal treatments. High pressure homogenization (HPH) and ultrasound (US) are two of the most promising approaches. They rely upon two different modes of action, although they share some mechanisms or ways of actions (mechanic burden against cells, cavitation and micronization, primary targets being the cell wall and the membrane, temperature and pressure playing important roles for their antimicrobial potential, and their effect on cells can be either positive or negative). HPH is generally used in milk and dairy products to break lipid micelles, whereas US is used for mixing and/or to obtain active compounds of food. HPH and US have been tested on pathogens and spoilers with different effects; thus, the main goal of this article is to describe how US and HPH act on biological systems, with a focus on antimicrobial activity, mode of action, positive effects, and equipment. The article is composed of three main parts: (i) an overview of US and HPH, with a focus on some results covered by other reviews (mode of action toward microorganisms and effect on enzymes) and some new data (positive effect and modulation of metabolism); (ii) a tentative approach for a comparative resistance of microorganisms; and (iii) future perspectives.

Effects of high pressure processing on the physicochemical and microbiological parameters, bioactive compounds, and antioxidant activity of a lemongrass-lime mixed beverage

This study determined the optimal pressure and time conditions for the high pressure processing (HPP) of a lemongrass-lime mixed beverage. The physicochemical and microbiological characteristics, bioactive compounds, and antioxidant activity of the beverage treated under the optimal HPP conditions were evaluated immediately after processing and during 8 weeks of storage at 4 °C, compared to untreated (control) and thermally pasteurized beverages. HPP at 250 MPa for 1 min at 25 °C ensured microbiological safety, according to inactivation tests with Listeria innocua as the target microorganism, without significant losses of vitamin C and phenolic compounds. Immediately after processing, the HPP treated beverage retained its original bioactive compounds content and showed physicochemical characteristics that were closer to the untreated control compared with the thermally pasteurized beverage. In addition, HPP provided microbiological quality and improved the shelf life of the beverage, demonstrating that it represents a reliable alternative to thermal treatment of lemongrass-lime mixed beverages.

Modification of enzymes by use of high-pressure homogenization

High-pressure is an emerging and relatively new technology that can modify various molecules. High-pressure homogenization (HPH) has been used in several studies on protein modification, especially in enzymes used or found in food, from animal, plant or microbial resources. According to the literature, the enzymatic activity can be modulated under pressure causing inactivation, stabilization or activation of the enzymes, which, depending on the point of view could be very useful. Homogenization can generate changes in the structure of the enzyme modifying various chemical bonds (mainly weak bonds) causing different denaturation levels and, consequently, affecting the catalytic activity. This review aims to describe the various alterations due to HPH treatment in enzymes, to show the influence of high-pressure on proteins and to report the HPH effects on the enzymatic activity of different enzymes employed in the food industry and research.

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.

The Effect of High Pressure Techniques on the Stability of Anthocyanins in Fruit and Vegetables

Anthocyanins are a group of phenolic compounds responsible for red, blue and violet colouration of many fruits, vegetables and flowers. The high content of these pigments is important as it influences directly their health promoting properties as well as the sensory quality of the product; however they are prone to degradation by, inter alia, elevated temperature and tissue enzymes. The traditional thermal methods of food preservation cause significant losses of these pigments. Thus, novel non-thermal techniques such as high pressure processing, high pressure carbon dioxide and high pressure homogenization are under consideration. In this review, the authors attempted to summarize the current knowledge of the impact of high pressure techniques on the stability of anthocyanins during processing and storage of fruit and vegetable products. Furthermore, the effect of the activity of enzymes involved in the degradation of these compounds has been described. The conclusions including comparisons of pressure-based methods with high temperature preservation techniques were presented.

Recent Advances in Food Processing Using High Hydrostatic Pressure Technology

High hydrostatic pressure is an emerging non-thermal technology that can achieve the same standards of food safety as those of heat pasteurization and meet consumer requirements for fresher tasting, minimally processed foods. Applying high-pressure processing can inactivate pathogenic and spoilage microorganisms and enzymes, as well as modify structures with little or no effects on the nutritional and sensory quality of foods. The U.S. Food and Drug Administration (FDA) and the U.S. Department of Agriculture (USDA) have approved the use of high-pressure processing (HPP), which is a reliable technological alternative to conventional heat pasteurization in food-processing procedures. This paper presents the current applications of HPP in processing fruits, vegetables, meats, seafood, dairy, and egg products; such applications include the combination of pressure and biopreservation to generate specific characteristics in certain products. In addition, this paper describes recent findings on the microbiological, chemical, and molecular aspects of HPP technology used in commercial and research applications.

High Pressure Homogenization of Porcine Pepsin Protease: Effects on Enzyme Activity, Stability, Milk Coagulation Profile and Gel Development

This study investigated the effect of high pressure homogenization (HPH) (up to 190 MPa) on porcine pepsin (proteolytic and milk-clotting activities), and the consequences of using the processed enzyme in milk coagulation and gel formation (rheological profile, proteolysis, syneresis, and microstructure). Although the proteolytic activity (PA) was not altered immediately after the HPH process, it reduced during enzyme storage, with a 5% decrease after 60 days of storage for samples obtained with the enzyme processed at 50, 100 and 150 MPa. HPH increased the milk-clotting activity (MCA) of the enzyme processed at 150 MPa, being 15% higher than the MCA of non-processed samples after 60 days of storage. The enzyme processed at 150 MPa produced faster aggregation and a more consistent milk gel (G' value 92% higher after 90 minutes) when compared with the non-processed enzyme. In addition, the gels produced with the enzyme processed at 150 MPa showed greater syneresis after 40 minutes of coagulation (forming a more compact protein network) and lower porosity (evidenced by confocal microscopy). These effects on the milk gel can be associated with the increment in MCA and reduction in PA caused by the effects of HPH on pepsin during storage. According to the results, HPH stands out as a process capable of changing the proteolytic characteristics of porcine pepsin, with improvements on the milk coagulation step and gel characteristics. Therefore, the porcine pepsin submitted to HPH process can be a suitable alternative for the production of cheese.

Effect of ultra-high pressure homogenisation processing on phenolic compounds, antioxidant capacity and anti-glucosidase of mulberry juice

In this study, the effects of ultra-high pressure homogenisation (UHPH) processing at 200 MPa for 1-3 successive passes (inlet temperatures at 4°C) were compared with pasteurisation (95°C, 1 min) processing on phenolic compounds, antioxidant capacity (ORAC value) and anti-glucosidase of mulberry juice. Compared with thermal pasteurisation processing, the more reductions in the anthocyanins, phenolic acids (gallic, protocatechuic, caffeic and p-coumaric acids, and a unknown hydroxycinnamic acid) and quercetin aglycone contents, as well as ORAC value were observed during UHPH processing of mulberry juice, whereas all reductions above during UHPH processing could be inhibited by adding ascorbic acid to mulberry juice. Besides, no significant change (p>0.05) in the α-glucosidase inhibitory activity was observed during UHPH processing of mulberry juice, but showed a 14% reduction in mulberry juice processed by thermal pasteurisation.