Effect of high-pressure processing on colour, texture and flavour of fruit- and vegetable-based food products: a review

Effect of High Hydrostatic Pressure Processing on the Anthocyanins Content, Antioxidant Activity, Sensorial Acceptance and Stability of Jussara (Euterpe edulis) Juice

Jussara (Euterpe edulis) fruit is a strong candidate for exportation due to its high content of anthocyanins. However, its rapid perishability impairs its potential for further economic exploration, highlighting the relevance of producing ready-to-drink juices by applying innovative processing, such as high hydrostatic pressure (HHP). The effect of HHP (200, 350, and 500 MPa for 5, 7.5, and 10 min) on anthocyanins content and antioxidant activity (AA) by FRAP and TEAC assays, and the most effective HHP condition on overall sensory acceptance and stability of jussara juice, were investigated. While mild pressurization (200 MPa for 5 min) retained anthocyanins and AA, 82% of anthocyanins content and 46% of TEAC values were lost at the most extreme pressurization condition (500 MPa for 10 min). The addition of 12.5% sucrose was the ideal for jussara juice consumer acceptance. No significant difference was observed for overall sensory acceptance scores of unprocessed (6.7) and HHP-processed juices (6.8), both juices being well-accepted. However, pressurization was ineffective in promoting the retention of anthocyanins and AA in jussara juice stored at refrigeration temperature for 60 days, probably due to enzymatic browning.

Validation of process technologies for enhancing the safety of low-moisture foods: A review

The outbreaks linked to foodborne illnesses in low-moisture foods are frequently reported due to the occurrence of pathogenic microorganisms such as Salmonella Spp. Bacillus cereus, Clostridium spp., Cronobacter sakazakii, Escherichia coli, and Staphylococcus aureus. The ability of the pathogens to withstand the dry conditions and to develop resistance to heat is regarded as the major concern for the food industry dealing with low-moisture foods. In this regard, the present review is aimed to discuss the importance and the use of novel thermal and nonthermal technologies such as radiofrequency, steam pasteurization, plasma, and gaseous technologies for decontamination of foodborne pathogens in low-moisture foods and their microbial inactivation mechanisms. The review also summarizes the various sources of contamination and the factors influencing the survival and thermal resistance of pathogenic microorganisms in low-moisture foods. The literature survey indicated that the nonthermal techniques such as CO₂ , high-pressure processing, and so on, may not offer effective microbial inactivation in low-moisture foods due to their insufficient moisture content. On the other hand, gases can penetrate deep inside the commodities and pores due to their higher diffusion properties and are regarded to have an advantage over thermal and other nonthermal processes. Further research is required to evaluate newer intervention strategies and combination treatments to enhance the microbial inactivation in low-moisture foods without significantly altering their organoleptic and nutritional quality.

Recent advances in extraction technologies for recovery of bioactive compounds derived from fruit and vegetable waste peels: A review

Fruits and vegetables are the most important commodities of trade value among horticultural produce. They are utilized as raw or processed, owing to the presence of health-promoting components. Significant quantities of waste are produced during fruits and vegetables processing that are majorly accounted by waste peels (∼90-92%). These wastes, however, are usually exceptionally abundant in bioactive molecules. Retrieving these valuable compounds is a core objective for the valorization of waste peel, besides making them a prevailing source of beneficial additives in food and pharmaceutical industry. The current review is focused on extraction of bioactive compounds derived from fruit and vegetable waste peels and highlights the supreme attractive conventional and non-conventional extraction techniques, such as microwave-assisted, ultrasound assisted, pulsed electric fields, pulsed ohmic heating, pressurized liquid extraction, supercritical fluid extraction, pressurized hot water, high hydrostatic pressure, dielectric barrier discharge plasma extraction, enzyme-assisted extraction and the application of "green" solvents say as well as their synergistic effects that have been applied to recover bioactive from waste peels. Superior yields achieved with non-conventional technologies were identified to be of chief interest, considering direct positive economic consequences. This review also emphasizes leveraging efficient, modern extraction technologies for valorizing abundantly available low-cost waste peel, to achieve economical substitutes, whilst safeguarding the environment and building a circular economy. It is supposed that the findings discussed though this review might be a valuable tool for fruit and vegetable processing industry to imply an economical and effectual sustainable extraction methods, converting waste peel by-product to a high added value functional product.

High Pressure Processing Impact on Alternariol and Aflatoxins of Grape Juice and Fruit Juice-Milk Based Beverages

High-pressure processing (HPP) has emerged over the last 2 decades as a good alternative to traditional thermal treatment for food safety and shelf-life extension, supplying foods with similar characteristics to those of fresh products. Currently, HPP has also been proposed as a useful tool to reduce food contaminants, such as pesticides and mycotoxins. The aim of the present study is to explore the effect of HPP technology at 600 MPa during 5 min at room temperature on alternariol (AOH) and aflatoxin B1 (AFB1) mycotoxins reduction in different juice models. The effect of HPP has also been compared with a thermal treatment performed at 90 °C during 21 s. For this, different juice models, orange juice/milk beverage, strawberry juice/milk beverage and grape juice, were prepared and spiked individually with AOH and AFB1 at a concentration of 100 µg/L. After HPP and thermal treatments, mycotoxins were extracted from treated samples and controls by dispersive liquid–liquid microextraction (DLLME) and determined by HPLC-MS/MS-IT. The results obtained revealed reduction percentages up to 24% for AFB1 and 37% for AOH. Comparing between different juice models, significant differences were observed for AFB1 residues in orange juice/milk versus strawberry juice/milk beverages after HPP treatment. Moreover, HPP resulted as more effective than thermal treatment, being an effective tool to incorporate to food industry in order to reach mycotoxins reductions.

Aspects of high hydrostatic pressure food processing: Perspectives on technology and food safety

The last two decades saw a steady increase of high hydrostatic pressure (HHP) used for treatment of foods. Although the science of biomaterials exposed to high pressure started more than a century ago, there still seem to be a number of unanswered questions regarding safety of foods processed using HHP. This review gives an overview on historical development and fundamental aspects of HHP, as well as on potential risks associated with HHP food applications based on available literature. Beside the combination of pressure and temperature, as major factors impacting inactivation of vegetative bacterial cells, bacterial endospores, viruses, and parasites, factors, such as food matrix, water content, presence of dissolved substances, and pH value, also have significant influence on their inactivation by pressure. As a result, pressure treatment of foods should be considered for specific food groups and in accordance with their specific chemical and physical properties. The pressure necessary for inactivation of viruses is in many instances slightly lower than that for vegetative bacterial cells; however, data for food relevant human virus types are missing due to the lack of methods for determining their infectivity. Parasites can be inactivated by comparatively lower pressure than vegetative bacterial cells. The degrees to which chemical reactions progress under pressure treatments are different to those of conventional thermal processes, for example, HHP leads to lower amounts of acrylamide and furan. Additionally, the formation of new unknown or unexpected substances has not yet been observed. To date, no safety-relevant chemical changes have been described for foods treated by HHP. Based on existing sensitization to non-HHP-treated food, the allergenic potential of HHP-treated food is more likely to be equivalent to untreated food. Initial findings on changes in packaging materials under HHP have not yet been adequately supported by scientific data.

Effects of Isochoric Freezing Conditions on Cut Potato Quality

Isochoric freezing is a pressure freezing technique that could be used to retain the beneficial effects of food storage at temperatures below their freezing point without ice damage. In this study, potato cylinders were frozen in an isochoric system and examined using full factorial combinations of three processing procedures (immersed in water, vacuum-packed and immersed in ascorbic acid solution), four freezing temperatures/pressures (−3 °C/37 MPa, −6 °C/71 MPa, −9 °C/101 MPa and −15 °C/156 MPa) and two average compression rates (less than 0.02 and more than 0.16 MPa/s). The effects of process variables on critical quality attributes of frozen potatoes after thawing were investigated, including mass change, volume change, water holding capacity, color and texture. Processing procedure and freezing temperature/pressure were found to be highly significant factors, whereas the significance of the compression rate was lower. For the processing procedures, immersion in an isotonic solution of 5% ascorbic acid best preserved quality attributes. At the highest pressure level of 156 MPa and low compression rate of 0.02 MPa/s, potato samples immersed in ascorbic acid retained their color, 98.5% mass and 84% elasticity modulus value. These samples also showed a 1% increase in volume and 13% increase in maximum stress due to pressure-induced hardening.

High-Pressure Processing and Ultrasonication of Minimally Processed Potatoes: Effect on the Colour, Microbial Counts, and Bioactive Compounds

HPP at 600 MPa alone, and in combination with US at 20 kHz (200 W), was applied to minimally processed potatoes of two commonly grown cultivars in Ireland. Changes in colour and microbial load (Enterobacteriaceae, total aerobic count, Salmonella, yeasts, and moulds) were monitored in vacuum-packaged potatoes during 14 days of storage at 4 °C. HPP and HPP/US significantly (p < 0.05) affected the colour parameters a*, b*, L*, and ΔE of minimally processed potatoes compared to the controls. Microbial growth was delayed in most of the treated samples with respect to those untreated (controls), while HPP completely inactivated Enterobacteriaceae in both cultivars. Total phenolic content and antioxidant activities were not altered in the treated samples of both varieties when compared to the controls. The levels of chlorogenic acid, ferulic acid, and caffeic acid were decreased after both treatments, with a significant (p < 0.05) increase in quinic acid in the treated samples as opposed to those untreated. A significant (p < 0.05) decrease in the levels of glycoalkaloids, namely α-chaconine and α-solanine, in HPP- and HPP/US-treated potatoes was also observed. These findings suggest that HPP and US can extend the shelf-life of minimally processed potatoes with a negligible impact on their antioxidant activity and phenolic content.

Induced Changes in Aroma Compounds of Foods Treated with High Hydrostatic Pressure: A Review

Since conventional thermal processing can have detrimental consequences on aroma compounds, non-thermal technologies such as high hydrostatic pressure (HHP) have been explored. HHP may alter the weak chemical bonds of enzymes. These changes can modify the secondary, tertiary, and quaternary structures of key enzymes in the production of aroma compounds. This can result in either an increase or decrease in their content, along with reactions or physical processes associated with a reduction of molecular volume. This article provides a comprehensive review of HHP treatment's effects on the content of lipid-derived aroma compounds, aldehydes, alcohols, ketones, esters, lactones, terpenes, and phenols, on various food matrices of vegetable and animal origin. The content of aldehydes and ketones in food samples increased when subjected to HHP, while the content of alcohols and phenols decreased, probably due to oxidative processes. Both ester and lactone concentrations appeared to decline due to hydrolysis reactions. There is no clear tendency regarding terpenes concentration when subjected to HHP treatments. Because of the various effects of HHP on aroma compounds, an area of opportunity arises to carry out future studies that allow optimizing and controlling the effect.

Identification and Characterization of Polyphenols from Carissa spinarum Fruit and Evaluation of Their Antioxidant and Anti-quorum Sensing Activity

Quorum sensing controls bacterial virulence through signaling molecules, which plays a vital role in managing foodborne pathogens that cause food spoilage and human infections. Though many synthetic compounds have been used to control infection, antibiotic resistance has become a global issue. Targeting the bacterial quorum sensing using the bioactive compounds could be an alternative strategy to combat their resistance. In this context, polyphenols from an unexplored unripe and ripe fruits of Carissa spinarum were evaluated for anti-quorum sensing activity. The study aimed at determining nutritional, phytochemical composition, and polyphenol profiling to evaluate their antioxidant potential of the fruit. Furthermore, the violacein inhibition, anti-biofilm, and effect on the motility of foodborne pathogens were also studied. The phytochemical content of C. spinarum fruit showed the phenolic and flavonoid content 273.20 mg GAE/100 g and 453.78 mg QE/100 g fresh weight , respectively, in ripe fruit. HPLC characterization of fruit extracts showed high content of syringic acid, resveratrol, and quercetin in ripe, whereas it showed epicatechin and gentisic acid in unripe fruit. The antioxidant activity of the ripe fruit extract exhibited a higher potential to scavenge DPPH radicals with IC₅₀ 4.69 mg/mL. Further, the anti-quorum sensing activity was higher in ripe fruit extract at 1.8 mg/mL inhibited with 78.65% violacein production in Chromobacterium violaceum, swimming motility, and biofilm formation in Pseudomonas aeruginosa and Yersinia enterocolitica (66.25% and 59.36% respectively at 1.2 mg/mL). Hence C. spinarum fruit bioactive could be a natural plant source for anti-quorum sensing activity to manage foodborne pathogens over synthetic compounds.

High pressure processing combined with selected hurdles: Enhancement in the inactivation of vegetative microorganisms

High pressure processing (HPP) as a nonthermal processing (NTP) technology can ensure microbial safety to some extent without compromising food quality. However, for vegetative microorganisms, the existence of pressure-resistant subpopulations, the revival of sublethal injury (SLI) state cells, and the resuscitation of viable but nonculturable (VBNC) state cells may constitute potential food safety risks and pose challenges for the further development of HPP application. HPP combined with selected hurdles, such as moderately elevated or low temperature, low pH, natural antimicrobials (bacteriocin, lactate, reuterin, endolysin, lactoferrin, lactoperoxidase system, chitosan, essential oils), or other NTP (CO₂ , UV-TiO₂ photocatalysis, ultrasound, pulsed electric field, ultrafiltration), have been highlighted as feasible alternatives to enhance microbial inactivation (synergistic or additive effect). These combinations can effectively eliminate the pressure-resistant subpopulation, reduce the population of SLI or VBNC state cells and inhibit their revival or resuscitation. This review provides an updated overview of the microbial inactivation by the combination of HPP and selected hurdles and restructures the possible inactivation mechanisms.

Comparative Evaluation of Four Extraction Methods of Antioxidant Compounds from Decatropis bicolor in Aqueous Medium Applying Response Surface Design

The objective of this paper is to compare conventional, ultrasound, microwave, and French press methods for the extraction of antioxidant compounds from Decatropis bicolor in an aqueous medium. This plant is widely used in Mexican traditional medicine for breast cancer treatment. Despite that, there are few studies on D. bicolor. Two response surface designs were applied to establish the best conditions of the liberation of antioxidants from D. bicolor, which were determined by DPPH• and Ferric Reducing Antioxidant Power (FRAP) techniques. The total phenolic content was evaluated by the Folin-Ciocalteu method. The results showed that D. bicolor is a source of antioxidants (669–2128 mg ET/100 g and 553–1920 mg EFe²⁺/100 g, respectively) and phenolic compounds (2232–9929 mg EGA/100 g). Among the physical factors that were analyzed, the temperature was the determinant factor to liberate the compounds of interest by using low concentrations of the sample and short times of extraction. The French press was the most efficient method, obtaining values of antioxidant activity and phenolic compounds even higher than those reported by using extraction methods with solvents such as methanol.

Progresses in processing technologies for special foods with ultra-long shelf life

Foods for special applications have recently received much attention due to rapid development of space and military industries as well as to frequent occurrence of natural and man-made disasters. Since the way such foods are processed clearly and directly affects their consumer's acceptability and shelf life, it is of interest to explore in detail how these special foods can be processed. This article presents a review on the difficulties in the processing, application and storage as well as on how to ensure the shelf life and acceptability of special foods through the use of efficient processing technologies. Emphasis is made on the use of both conventional and alternative thermal processing and irradiation technologies. Appropriate packaging technologies for each of the discussed special foods are also mentioned along with the way to overcome the problem of product quality degradation. Through comparison and analysis, it is found that foods with different attributes require different technologies and processes to achieve desirable results. Combined use of multiple technologies has also noted to be advantageous.

Influence of high hydrostatic pressure pretreatment on properties of vacuum-freeze dried strawberry slices

Effects of high hydrostatic pressure (HHP) (50, 100, 150, 200 and 250 MPa) pretreatment on water mobility and distribution, drying duration, microstructure, color, cell wall fraction and tissue structure of strawberry slices were investigated. HHP significantly increased water mobility of the strawberry slices, resulting in the reduction of drying duration by 9-24%. As the pretreatment pressure was increased, redness value and anthocyanin content continuously increased, soluble pectin (SBP) content increased and then decreased, while the contents of protopectin (PTP) and cellulose decreased. After the HHP pretreatment, chromoplasts and moisture was distributed more uniformly in the strawberry slices. Microscopy images showed the formation of microscopic holes or channels in the matrix and the breakdown of tissue structure by HHP. Results suggested HHP pretreatment disrupted the integrity of the fresh strawberry which enhanced the drying efficiency and migration of the chromoplasts during the vacuum-freeze drying process.

Effects of high hydrostatic pressure on the binding capacity, interaction, and antioxidant activity of the binding products of cyanidin-3-glucoside and blueberry pectin

In this study, the effects of high hydrostatic pressure (HP) treatment on the binding capacity, interaction, and antioxidant activity of the binding products of blueberry pectin (BP) and cyanidin-3-glucoside (C3G) were assessed. HP was found to significantly improve the adsorption between C3G and BP. After binding, the C3G concentration was found to be the highest (382.1 ± 13.2 μg/mg for BP) when using a C3G-BP mass ratio of 1:2, a pressure of 400 MPa, and a holding time of 15 min. HP processing decreased particle size and altered the characteristics of C3G-BP complexes. The main binding form of the complexes before HP treatment was pectin-wrapped C3G by hydrogen bond interaction, while HP caused charged groups in pectin to be more exposed and improve the electrostatic interaction between C3G and BP. The antioxidant activity results showed that the presence of BP could protect the ferric-reducing antioxidant power of C3G after HP treatment.

High pressure and thermal processing on the quality of zucchini slices

In response to the market demand for low processed vegetables, high-pressure treatments (400,600 MPa; 1,5 min) were applied on zucchini slices and compared to a traditional blanching treatment. Histological observations, texture and color analysis, pectinmethylesterase (PME) and antioxidant (DPPH) activities were measured and compared to untreated samples. The histological observations revealed that the longer high-pressure treatments (5 min) led to more extended cell lysis and dehydration than the shorter ones (1 min) and blanching. High-pressure treatments resulted less effective than blanching on PME inactivation, with the best results obtained at 400 MPa for 1 min. Comparable texture parameters were observed for high-pressured and blanched samples. The negative correlation found between PME activity and the texture parameter ‘distance of the first peak force’ revealed an effect of PME on the texture recovery after treatments. High pressure led to a general browning of zucchini parenchyma and to DPPH drop. The correlations found between DPPH and color suggest the common nature of the phenomena. The influence of pressure and time on the studied parameters was revealed by two-way ANOVA. Principal component analysis clustered together the four high-pressure-treated samples, being clearly divided by blanched and untreated ones.

The type of microorganism and substrate determines the odor fingerprint of dried bacteria targeting microbial protein production

The rapidly increasing demand for protein has led to the pursuit of new protein sources, among which microbial protein (MP) is one of the most promising. Although the nutritional properties of MP are important and often well-studied, the sensory properties of the microbial cells will in part determine the commercial success of the product and are much less investigated. Here we assessed the odor fingerprint of dried bacteria originating from pure cultures and enriched mixed microbial communities using an electronic nose (e-nose). The e-nose discriminated between the different MP sources, while the choice of culture and substrate substantially affected their volatile organic compound (VOC) profile. The most dominant odor descriptors (>20% of VOC peak area) were sweet, fruity and fishy, while the mixed cultures presented higher peak areas indicating potentially more intense aromas than the pure cultures. The e-nose can detect the suitability of new MP sources and determine their best end-use.

Effects of high pressure processing (HPP) on microorganisms and the quality of mango smoothies during storage

The objective of this study is to investigate the effects of high pressure processing (HPP) on the quality of mango smoothies and the inactivation of microorganisms therein, with heat treatments used as the control. Comparative analysis was conducted on the microbiological changes in the mango smoothies subjected to HPP at 400-600 MPa for 0-15 min. The total plate count (TPC) and the yeast and mold (YM) counts were found to be significantly inactivated through increases in the pressure and treatment time (p < 0.05). Conditions of 90 °C/20 min (HT), 500 MPa/8 min (HPP-500) and 600 MPa/5 min (HPP-600) were, thus, selected as the subsequent treatment for a storage study at 4 °C for 15 days, since these conditions had similar inactivation effects on TPC and YM. After 15 days of storage, the TPC was found to have increased by 3.87, 3.54 and 3.36 log10 cycles in the mango smoothies treated by HT, HPP-500 and HPP-600, respectively, while the YM counts remained at less than 1 log10 cycle in all samples. During storage, compared to the HT and HPP-600 samples, both the color and viscosity at 100 s-1 of samples treated by HPP-500 were found to be better maintained. Carotene content was better retained in storage after the HPP process than after the HT process. However, the different treatments had no effect on the pH nor on the total soluble solids (TSS) in the samples. The study ascertained that HPP-500 is able to ensure both the microbial safety and the quality of mango smoothies more effectively than HT and HPP-600.

Impact of Ohmic Heating and High Pressure Processing on Qualitative Attributes of Ohmic Treated Peach Cubes in Syrup

Stabilization of ohmic pretreated peach cubes (ohm) in syrup, representative of semifinished fruit products, was finalized by ohmic heating (OHM) and high pressure processing (HPP), proposed respectively as thermal and nonthermal pasteurization, in comparison to a conventional pasteurization treatment (DIM). The samples were then studied in terms of histological, physical (dimensional distribution, tenderometry, texture, viscosity of syrup and colour), chemical (total phenolic and ascorbic acid content), and sensorial (triangle test) properties. Severe modifications of the cell walls were observed in ohm-DIM and ohm-OHM samples, with swelling and electroporation, respectively. From chemical analyses, significant reduction of ascorbic acid and simultaneous increase of total phenolics content were observed for ohm-DIM and ohm-OHM, probably in relation to the cell wall damages. ohm-HPP showed the best preservation of the dimensional characteristics and hardness, followed by ohm-OHM and ohm-DIM. In addition, textural and colour parameters evidenced similar results, with ohm-HPP as the less different from ohm. Finally, the sensorial analysis confirmed ohm-HPP and ohm-OHM samples as the most similar to ohm as well as the most appreciated in terms of colour and consistency.

Flexible Screen Printed Aptasensor for Rapid Detection of Furaneol: A Comparison of CNTs and AgNPs Effect on Aptasensor Performance

Furaneol is a widely used flavoring agent, which can be naturally found in different products, such as strawberries or thermally processed foods. This is why it is extremely important to detect furaneol in the food industry using ultra-sensitive, stable, and selective sensors. In this context, electrochemical biosensors are particularly attractive as they provide a cheap and reliable alternative measurement device. Carbon nanotubes (CNTs) and silver nanoparticles (AgNPs) have been extensively investigated as suitable materials to effectively increase the sensitivity of the biosensors. However, a comparison of the performance of biosensors employing CNTs and AgNPs is still missing. Herein, the effect of CNTs and AgNPs on the biosensor performance has been thoughtfully analyzed. Therefore, disposable flexible and screen printed electrochemical aptasensor modified with CNTs (CNT-ME), or AgNPs (AgNP-ME) have been developed. Under optimized conditions, CNT-MEs showed better performance compared to AgNP-ME, yielding a linear range of detection over a dynamic concentration range of 1 fM-35 μM and 2 pM-200 nM, respectively, as well as high selectivity towards furaneol. Finally, our aptasensor was tested in a real sample (strawberry) and validated with high-performance liquid chromatography (HPLC), showing that it could find an application in the food industry.

Stability and in vitro simulated release characteristics of ultrasonically modified soybean lipophilic protein emulsion

Natural emulsifiers such as soybean lipophilic protein (SLP) show potential as delivery systems for hydrophobic bioactive components such as vitamin E; however, the solubility of SLP is limited by its high lipid content. This study evaluated the effects of various ultrasonic conditions on the structure and properties of SLP. Using an emulsion of modified SLP, the carrier properties and in vitro digestion and release properties for vitamin E were evaluated. Biochemical and spectroscopic analyses indicated that the ultrasonic treatment mainly changed the secondary and tertiary structures of SLP. Furthermore, appropriate ultrasonic conditions significantly improved the solubility and emulsifying properties of SLP, with the highest emulsion stability and SLP encapsulation efficiency obtained using an ultrasonic power of 240 W for 20 min. An in vitro digestion simulation revealed that the emulsion prepared by ultrasonic modification of SLP was an effective delivery system for vitamin E. In particular, the emulsion protected the biological activity of vitamin E while significantly increasing the rate of lipid digestion and the bioavailability of vitamin E. These results indicate that the ultrasonically modified SLP can be used to prepare a stable emulsion for encapsulating vitamin E, which provides a new approach for the delivery of hydrophobic bioactive components.

Changes in Physicochemical Properties and Volatiles of Kiwifruit Pulp Beverage Treated with High Hydrostatic Pressure

Physicochemical properties and volatiles of kiwifruit pulp beverage treated with high hydrostatic pressure (HHP, 400–600 MPa/5–15 min) were investigated during 40-day refrigerated storage. Compared with heat treatment (HT), HHP ranged from 400–500 MPa was superior in retaining vitamin C, fresh-like color and volatiles, while soluble solids content and pH were not affected significantly. Furthermore, HHP improved brightness and inhibited browning of kiwifruit pulp beverage. Samples treated at 400 MPa for 15 min showed significantly higher vitamin C content and lower ∆E values over 40 days than heat-treated kiwifruit pulp beverage. The total content of alcohols, esters, acids, and ketones gradually increased, whereas the total aldehydes content decreased during storage. Interestingly, HHP treatment at 500 MPa for 15 min mostly retained important characteristic volatiles including hexanal and (E)-2-hexenal, indicating this treatment was more conducive to preserve the original fruity, fresh, grassy and green notes of kiwifruit pulp beverage than HT.

Extraction of bioactive compounds from purple corn using emerging technologies: A review

The increase in the use of bioactive compounds from purple corn in the food and pharmaceutical industries has led to the investigation of nonconventional extraction technologies that allow one to obtain more of these compounds. In this context, nonconventional techniques, known as emerging technologies, use more efficient processes that are safe for the environment, in addition to obtaining products with better functional characteristics as compared to those obtained by conventional technologies. This review aims to provide information on different nonconventional techniques used in the extraction of bioactive compounds from purple corn.

Impact of High-Pressure Process on Probiotics: Viability Kinetics and Evaluation of the Quality Characteristics of Probiotic Yoghurt

The impact of high-pressure (HP) processing on the viability of two probiotic microorganisms (Bifidobacterium bifidum and Lactobacillus casei) at varying pressure (100−400 MPa), temperature (20−40 °C) and pH (6.5 vs. 4.8) conditions was investigated. Appropriate mathematical models were developed to describe the kinetics of the probiotics viability loss under the implemented HP conditions, aiming to the development of a predictive tool used in the design of HP-processed yoghurt-like dairy products. The validation of these models was conducted in plain and sweet cherry-flavored probiotic dairy beverage products pressurized at 100−400M Pa at ambient temperature for 10 min. The microbiological, rheological, physicochemical and sensory characteristics of the HP-treated probiotic dairy beverages were determined in two-week time intervals and for an overall 28 days of storage. Results showed that the application of HP in the range of 200−300 MPa had minimal impact on the probiotic strains viability throughout the entire storage period. In addition, the aforementioned HP processing conditions enhanced the rheological and sensory properties without affecting post-acidification compared to the untreated product analogues.

Combination of High Hydrostatic Pressure and Ultrafiltration to Generate a New Emulsifying Ingredient from Egg Yolk

Egg yolk granule phosvitin (45 kDa) is a phosphoprotein known for its emulsifying properties. Recently, high hydrostatic pressure (HHP) treatment of granule induced the transfer of phosvitin to the soluble plasma fraction. This project evaluated the performance of the ultrafiltration (UF) used to concentrate phosvitin from the plasma fraction to produce a natural emulsifier. Phosvitin was characterized in plasma from a pressure-treated granule (1.73 ± 0.07% w/w) and in its UF retentate (26.00 ± 4.12% w/w). The emulsifying properties of both retentates were evaluated. The emulsion prepared with phosvitin-enriched retentate was more resistant to flocculation and creaming. Confocal laser scanning microscopy showed a network of aggregated protein similar to a gel, which encapsulated oil droplets in emulsions made with UF-retentate of plasma from pressure-treated granule. However, although sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) showed that β-phosvitin is recovered in the cream, it is difficult to attribute the improved emulsifying properties of the UF-retentate of plasma from pressure-treated granules only to phosvitin.

Mulberry Fruit Extract Ameliorates Adipogenesis via Increasing AMPK Activity and Downregulating MicroRNA-21/143 in 3T3-L1 Adipocytes

Mulberry (Morus alba L.) fruits have long been used in traditional medicine and as edible berries in many countries. This study investigated the antiadipogenic effect of high hydrostatic pressure mulberry fruit extract (MFE) during 3T3-L1 adipocyte differentiation. MFE decreased lipid and triglyceride accumulation and glycerol-3-phosphate dehydrogenase activity. The mRNA expression levels of genes related to adipogenesis, such as the adipocyte protein 2, proliferator-activated receptor-γ, and CCAAT/enhancer binding protein-α, were suppressed by MFE. They also reduced microRNA (miR)-21 and miR-143 expression, which are involved in adipogenesis. In contrast, adenosine monophosphate-activated protein kinase (AMPK) activity was increased by MFE. These results suggested that MFE may suppress adipogenesis through modulating miR-21/143 expression and AMPK activity in 3T3-L1 adipocytes, which may be useful as antiobesity food agents.