High pressure processing of carrot juice: Effect of static and multi-pulsed pressure on the polyphenolic profile, oxidoreductases activity and colour

Health-Promoting Effects, Phytochemical Constituents and Molecular Genetic Profile of the Purple Carrot 'Purple Sun' (Daucus carota L.)

The purple carrot cultivar 'Purple Sun' (Daucus carota L.) is characterized by a relevant content of phenolic compounds and anthocyanins, which may play an important role in reducing the risk of chronic diseases and in the treatment of metabolic syndrome. In the present study, the genetic diversity, phytochemical composition, and bioactivities of this outstanding variety were studied for the first time. Genetic analysis by molecular markers estimated the level of genetic purity of this carrot cultivar, whose purple-pigmented roots were used for obtaining the purple carrot ethanol extract (PCE). With the aim to identify specialized metabolites potentially responsible for the bioactivities, the analysis of the metabolite profile of PCE by LC-ESI/LTQ Orbitrap/MS/MS was carried out. LC-ESI/HRMS analysis allowed the assignment of twenty-eight compounds, putatively identified as isocitric acid (1), phenolic acid derivatives (2 and 6), hydroxycinnamic acid derivatives (9, 10, 12-14, 16, 17, 19, 22, and 23), anthocyanins (3-5, 7, 8, 11, and 18), flavanonols (15 and 21), flavonols (20 and 24), oxylipins (25, 26, and 28), and the sesquiterpene 11-acetyloxytorilolone (27); compound 26, corresponding to the primary metabolite trihydroxyoctanoic acid (TriHOME), was the most abundant compound in the LC-ESI/HRMS analysis of the PCE, and hydroxycinnamic acid derivatives followed by anthocyanins were the two most represented groups. The antioxidant activity of PCE, expressed in terms of reactive oxygen species (ROS) level and antioxidant enzymes activity, and its pro-metabolic effect were evaluated. Moreover, the antibacterial activity on Gram (-) and (+) bacterial strains was investigated. An increase in the activity of antioxidant enzymes (SOD, CAT, and GPx), reaching a maximum at 0.5 mg/mL of PCE with a plateau at higher PCE concentrations (1.25, 2.5, and 5.0 mg/mL), was observed. PCE induced an initial decrease in ROS levels at 0.1 and 0.25 mg/mL concentrations, reaching the ROS levels of control at 0.5 mg/mL of PCE with a plateau at higher PCE concentrations (1.25, 2.5, and 5.0 mg/mL). Moreover, significant antioxidant and pro-metabolic effects of PCE on myoblasts were shown by a reduction in ROS content and an increase in ATP production linked to the promotion of mitochondrial respiration. Finally, the bacteriostatic activity of PCE was shown on the different bacterial strains tested, while the bactericidal action of PCE was exclusively observed against the Gram (+) Staphylococcus aureus. The bioactivities of PCE were also investigated from cellular and molecular points of view in colon and hematological cancer cells. The results showed that PCE induces proliferative arrest and modulates the expression of important cell-cycle regulators. For all these health-promoting effects, also supported by initial computational predictions, 'Purple Sun' is a promising functional food and an optimal candidate for pharmaceutical and/or nutraceutical preparations.

Exploring the impact of high pressure processing on the characteristics of processed fruit and vegetable products: a comprehensive review

Consumers are increasingly interested in additive-free products with a fresh taste, leading to a growing trend in high pressure processing (HPP) as an alternative to thermal processing. This review explores the impact of HPP on the properties of juices, smoothies, and purees, as well as its practical applications in the food industry. Research findings have explained that HPP is a most promising technology in comparison to thermal processing, in two ways i.e., for ensuring microbial safety and maximum retention of micro and macro nutrients and functional components. HPP preserves natural color and eliminates the need for artificial coloring. The review also emphasizes its potential for enhancing flavor in the beverage industry. The review also discusses how HPP indirectly affects plant enzymes that cause off-flavors and suggests potential hurdle approaches for enzyme inactivation based on research investigations. Scientific studies regarding the improved quality insights on commercially operated high pressure mechanisms concerning nutrient retention have paved the way for upscaling and boosted the market demand for HPP equipment. In future research, the clear focus should be on scientific parameters and sensory attributes related to consumer acceptability and perception for better clarity of the HPP effect on juice and smoothies/purees.

A multidimensional strategy for characterization, distinction, and quality control of two Clinopodium medicinal plants

ETHNOPHARMACOLOGICAL RELEVANCE

Clinopodium chinense Kuntze (CC) and Clinopodium polycephalum (Vaniot) C. Y. Wu & S. J. Hsuan (CP) are both included in the Pharmacopoeia of the People's Republic of China (edition 2020) as the legitimate source of "Duan Xue Liu" (DXL), which is a crucial traditional Chinese medicine used as a clinical remedy for bleeding diseases. However, the differences in plant endogenous metabolites and bioactivities between CC and CP are still unclear.

AIM OF THE STUDY

This study aims to provide a scientific basis to investigate the differences between CC and CP ensuring the efficient and safe use of DXL.

MATERIALS AND METHODS

A multidimensional strategy including plant metabolomics, digital reference standard (DRS) analyzer, and biological activities assay was creatively constructed for the characterization, distinction, and quality control of CC and CP.

RESULTS

There were apparent differences in the metabolites between CC and CP. 7 compounds contributing to the differences were successfully identified. On that basis, linear calibration using two reference substances (LCTRS) methods was proved as a more accurate and specific quality analysis method for CC and CP. In addition, bioactivity assays showed that both CC and CP exhibited obvious hemostatic activity, while CC showed greater potential to resist inflammation and free radicals.

CONCLUSION

In summary, it was the first time to investigate the chemical constituents and bioactivities differences between CC and CP with the help of plant metabolomics, DRS study, and biological activity assays. These two plants were significantly separated in the integrated analysis, suggesting that we should pay attention to the distinction to prevent unexpected risks caused by medicinal materials.

Therapeutic Potential of Chlorogenic Acid in Chemoresistance and Chemoprotection in Cancer Treatment

Chemotherapeutic drugs are indispensable in cancer treatment, but their effectiveness is often lessened because of non-selective toxicity to healthy tissues, which triggers inflammatory pathways that are harmful to vital organs. In addition, tumors' resistance to drugs causes failures in treatment. Chlorogenic acid (5-caffeoylquinic acid, CGA), found in plants and vegetables, is promising in anticancer mechanisms. In vitro and animal studies have indicated that CGA can overcome resistance to conventional chemotherapeutics and alleviate chemotherapy-induced toxicity by scavenging free radicals effectively. This review is a summary of current information about CGA, including its natural sources, biosynthesis, metabolism, toxicology, role in combatting chemoresistance, and protective effects against chemotherapy-induced toxicity. It also emphasizes the potential of CGA as a pharmacological adjuvant in cancer treatment with drugs such as 5-fluorouracil, cisplatin, oxaliplatin, doxorubicin, regorafenib, and radiotherapy. By analyzing more than 140 papers from PubMed, Google Scholar, and SciFinder, we hope to find the therapeutic potential of CGA in improving cancer therapy.

Influence of ultrasound on the microbiological, physicochemical properties, and sensory quality of different varieties of pumpkin juice

This study has investigated the effect of ultrasound (US) as an emerging non-thermal sterilization technique on microbial growth and quality changes in three freshly squeezed pumpkin juices (Cucurbita maxima Duchesne, Cucurbita moschata Duchesne, and Cucurbita pepo L.).The three pumpkin juices were ultrasonicated at different ultrasonic power (0-400 W), time (0-20 min), and temperature (0-30 °C), and the total colony counts of the treated pumpkin juices were less than 5 log CFU/mL, which complied with the food safety and consumption standards. Based on these results, we further investigated the effects of different ultrasonic power (25 kHz, 10 min, 20 °C, 0-400 W) on the physicochemical properties and sensory quality of the three pumpkin juices. The physicochemical properties (color, sugar content, organic acid content, soluble solids, and carotenoids) of treated pumpkin juice were retained or improved to some extent. The antioxidant capacity was also increased by 9.09%, 10.25%, and 16.9% compared to the untreated group. During sonication, the particle size of all samples decreased significantly, the microstructure broke down significantly, and the sensory qualities of pumpkin juice were well preserved after sonication.

Benefits of isochoric freezing for carrot juice preservation

Isochoric freezing (IF) at -5°C/77 and -10°C/100 MPa was used to preserve carrot juice for 12 weeks. The juice qualities were compared to those using heat treatment (HT) at 95°C for 15 s followed by cold storage at 4°C. The native population of total aerobic bacteria, yeasts, and molds in isochoric frozen juice remained below the detection limit for 12 weeks. In comparison, microbes started to grow in heat-treated juices after 3 weeks of refrigeration. The color of isochoric frozen juice appeared more deep orange than the fresh juice due to an increase in carotenoid extractability. IF was not effective in reducing the activities of peroxidase, polyphenol oxidase, and pectin methyl esterase compared with HT. However, the isochoric samples showed higher carotenoid content, polyphenol content, and antioxidant capacity compared to the fresh and heat-treated juices. PRACTICAL APPLICATION: Isochoric freezing was used to produce carrot juice with extended shelf life. Isochoric freezing could be a beneficial alternative to conventional heat treatment for carrot juice processing as the applied pressures reached total inactivation levels of spoilage microorganisms. Moreover, the low processing temperatures better retained desirable compounds and quality attributes of fresh juice throughout its shelf life.

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.

Behavior of enzymes under high pressure in food processing: mechanisms, applications, and developments

High pressure processing (HPP) offers the benefits of safety, uniformity, energy-efficient, and low waste, which is widely applied for microbial inactivation and shelf-life extension for foods. Over the past forty years, HPP has been extensively researched in the food industry, enabling the inactivation or activation of different enzymes in future food by altering their molecular structure and active site conformation. Such activation or inactivation of enzymes effectively hinders the spoilage of food and the production of beneficial substances, which is crucial for improving food quality. This paper reviews the mechanism in which high pressure affects the stability and activity of enzymes, concludes the roles of key enzymes in the future food processed using high pressure technologies. Moreover, we discuss the application of modified enzymes based on high pressure, providing insights into the future direction of enzyme evolution under complex food processing conditions (e.g. high temperature, high pressure, high shear, and multiple elements). Finally, we conclude with prospects of high pressure technology and research directions in the future. Although HPP has shown positive effects in improving the future food quality, there is still a pressing need to develop new and effective combined processing methods, upgrade processing modes, and promote sustainable lifestyles.

Applications of ultrasonication on food enzyme inactivation- recent review report (2017-2022)

Ultrasound processing has been widely applied in food sector for various applications such as decontamination and structural and functional components modifications in food. Enzymes are proteinaceous in nature and are widely used due to its catalytic activity. To mitigate the undesirable effects caused by the enzymes various technologies have been utilized to inactive the enzymes and improve the enzyme efficiency. Ultrasound is an emerging technology that produces acoustic waves which causes rapid formation and collapse of bubbles. It has the capacity to break the hydrogen bonds and interact with the polypeptide chains due to Vander Waals forces leading to the alteration of the secondary and tertiary structure of the enzymes thereby leading to loss in their biological activity. US effectively inactivates various dairy-related enzymes, including alkaline phosphatase (ALP), lactoperoxidase (LPO), and γ-glutamyl transpeptidase (GGTP) with increased US intensity and time without affecting the natural dairy flavors. The review also demonstrates that inactivation of enzymes presents in fruit and vegetables such as polyphenol oxidase (PPO), polygalacturonase (PG), Pectin methyl esterase (PME), and peroxidase. The presence of the enzymes causes detrimental effects causes off-flavors, off-colors, cloudiness, reduction in viscosity of juices, therefore the formation of high-energy free molecules during sonication affects the catalytic function of enzymes and thereby causing inactivation. Therefore this manuscript elucidates the recent advances made in the inactivation of common, enzymes infruits, vegetables and dairy products by the application of ultrasound and also explains the enzyme inactivation kinetics associated. Further this manuscript also discusses the ultrasound with other combined technologies, mechanisms, and its effects on the enzyme inactivation.

The Effect of Storage and Pasteurization (Thermal and High-Pressure) Conditions on the Stability of Phycocyanobilin and Phycobiliproteins

The utilization of natural blue pigments in foods is difficult as they are usually unstable during processing and the commonly applied pH. The current study focuses on natural blue pigment, possessing antioxidant properties, found in Arthrospira platensis (spirulina), and phycobiliproteins (PBP). These pigments are a complex of conjugated protein and non-protein components, known as phycocyanobilin. PBP has low stability during pasteurization (high-pressure or heat treatments), resulting in protein denaturation and color deterioration that limits the application. The phycocyanobilin pigment might also be liable to oxidation during pasteurization and storage, resulting in color deterioration. Yet, the instability of the pigment phycocyanobilin during the pasteurization process and storage conditions was never studied before, limiting the comprehensive understanding of the reasons for PBP instability. In this study, the stability of phycocyanobilin under high-pressure and high-temperature conditions was compared to the stability of phycobiliproteins. We revealed that phycobiliproteins have a higher color deterioration rate at 70–80 °C than at high-pressure (300–600 MPa) whereas phycocyanobilin remained stable during high-pressure and heat processing. During storage at pH 7, phycocyanobilin was oxidized, and the oxidation rate increased with increasing pH, while at lower pH phycocyanobilin had low solubility and resulted in aggregation.

Activity and stability of lipase from Candida Antarctica after treatment in pressurized fluids

Lipase B from Candida antarctica (CalB) is one of the biocatalysts most used in organic synthesis due to its ability to act in several medium, wide substrate specificity and enantioselectivity, tolerance to non-aqueous environment, and resistance to thermal deactivation. Thus, the objective of this work was to treat CalB in supercritical carbon dioxide (SC-CO₂) and liquefied petroleum gas (LPG), and measure its activity before and after high-pressure treatment. Residual specific hydrolytic activities of 132% and 142% were observed when CalB was exposed to SC-CO₂ at 35 ℃, 75 bar and 1 h and to LPG at 65 ℃, 30 bar and 1 h, respectively. Residual activity of the enzyme treated at high pressure was still above 100% until the 20th day of storage at low temperatures. There was no difference on the residual activity loss of CalB treated with LPG and stored at different temperatures over time. Greater difference was observed between CalB treated with CO₂ and flash-frozen in liquid nitrogen (- 196 ℃) followed by storage in freezer (- 10 ℃) and CalB stored in freezer at - 10 ℃. Such findings encourage deeper studies on CalB as well as other enzymes behavior under different types of pressurized fluids aiming at industrial application.

Comprehensive evaluation of the effect of five sterilization methods on the quality of black carrot juice based on PCA, TOPSIS and GRA models

The effect of thermal pasteurization (TP), high temperature long time (HTLT), ultra-high temperature instantaneous (UHT), high hydrostatic pressure (HHP) and thermosonication (TS) sterilization on the physicochemical, sensory and functional properties of black carrot juice (BCJ) were studied. And for the first time, the comprehensive quality of sterilized BCJ was quantified by mathematical modeling. UHT was the least suitable sterilization method for BCJ resulting from the most severe deterioration in functional properties. TS had adverse effects on sensory and physicochemical properties, but significantly increased the total flavonoids and anthocyanins contents (p < 0.05) and showed the strongest antioxidant activity, making it a nutritional high-value processing method. TP and HHP balanced the improvement of sensory properties and the retention of functional properties, which were the most suitable sterilization methods for BCJ. This study determined the optimal sterilization methods of BCJ, and provided a scientific solution for the screening of high quality processing methods.

The effect of supercritical carbon dioxide on the physiochemistry, endogenous enzymes, and nutritional composition of fruit and vegetables and its prospects for industrial application: a overview

Consumers have an increasing demand for fruit and vegetables with high nutritional value worldwide. However, most fruit and vegetables are vulnerable to quality loss and spoilage during processing, transportation, and storage. Among the recently introduced emerging technologies, supercritical carbon dioxide (SCCO2) has been extensively utilized to treat and maintain fruit and vegetables mainly due to its nontoxicity, safety, and environmentally friendly. SCCO2 technology generates low processing costs and mild processing conditions (temperature and pressure) that allow for the application of CO2 at a supercritical state. This review aimed to summarize the current knowledge on the influence of SCCO2 technology on the quality attributes of fruit and vegetable products, such as physicochemical properties (pH, color, cloud, particle size distribution, texture), sensory quality, and nutritional composition (ascorbic acid, phenolic compounds, anthocyanins, carotenoids, and betalains). In addition, the effects and mechanisms of the SCCO2 technique on endogenous enzyme inactivation (polyphenol oxidase, peroxidase, and pectin methylesterase) were also elucidated. Finally, the prospects of the SCCO2 technique for industrial application was discussed from the economic and regulatory aspect.

Newly generated and increased bound phenolic in lychee pulp during heat-pump drying detected by UPLC-ESI-triple-TOF-MS/MS

BACKGROUND

During the thermal processing of fruit, it has been observed for phenolic compounds to either degrade, polymerize, or transfer into macromolecules. In this study, the bound and free phenolic compound composition, content, and phenolic-related enzyme activity of lychee pulp were investigated to determine whether the free phenolic had converted to bound phenolic during heat-pump drying (HPD).

RESULTS

It was found that after HPD, when compared with the fresh lychee pulp (control), the content of bound phenolics of dried lychee pulp had increased by 62.69%, whereas the content of free phenolics of dried lychee pulp decreased by 22.26%. It was also found that the antioxidant activity of bound phenolics had also increased after drying. With the use of high-performance liquid chromatography-tandem mass spectrometry, it was identified that (+)-gallocatechin, protocatechuic aldehyde, isorhamnetin-3-O-rutoside, 3,4-dihydroxybenzeneacetic acid, and 4-hydroxybenzoic acid were newly generated during HPD, when compared with the control sample. After drying, the contents of gallic acid, catechin, 4-hydroxybenzoic acid, vanillin, syringic acid, and quercetin in bound phenolics had also increased, and polyphenol oxidase and peroxidase still showed enzyme activity, which could be related to the conversion of free phenolics to bound phenolics.

CONCLUSION

Overall, during the thermal processing of lychee pulp, the free phenolics weres found to be converted into bound phenolics, new substances were generated, and antioxidant activity was increased. Hence, it was concluded that HPD improved the bound phenolics content of lychee pulp, thus providing theoretical support for the lychee processing industry. © 2021 Society of Chemical Industry.

High-pressure and thermal processing of cloudy hawthorn berry (Crataegus pinnatifida) juice: Impact on microbial shelf-life, enzyme activity and quality-related attributes

The study aimed to evaluate the effect of high-pressure (HPP, 300/600 MPa for 2 and 6 min) and thermal processing (TP, 65 °C/30 min) on microbial shelf-life, enzyme-activity and quality-attributes of cloudy hawthorn berry juice (CHBJ) after processing and during storage (4 °C). The CHBJ shelf-life was at least 150 days when processed by HPP. No significant difference was observed in pH and titratable acidity (p > 0.05), while HPP significantly increased soluble sugar (p < 0.05) and simulated some fruity aroma compounds which improved the taste and flavor of CHBJ. However, HPP inhabited ineffectively enzyme-activity in comparison to TP, causing significant color changes (ΔE = 4.98 ± 0.03-5.10 ± 0.07) during 30-day storage (p < 0.05). Although particle size increased after HPP treatment, significant increases (68.76%-926.95%) were observed in viscosity (p < 0.05), due to enhanced extractability or modification of pectin induced by HPP, resulting in higher consistency of CHBJ. HPP is promising to extend shelf-life and improve quality-attributes of CHBJ.

Effects of ultrasonic treatment on color, carotenoid content, enzyme activity, rheological properties, and microstructure of pumpkin juice during storage

Freshly squeezed pumpkin juice (Cucurbita moschata D.) was sonicated at various power levels at a constant frequency of 25 kHz and a treatment time of 10 min. Samples were stored in the dark for 0, 4, 8, and 12 days at 4 °C and were subsequently analyzed. The combined effects of power level and storage period on color parameters, carotenoid content, particle size distribution, cloud value, rheological characteristics, and microstructure were investigated. The results showed ultrasonic-treated samples had little effect on carotenoid content, cloud value, particle size distribution, and polydispersity during storage compared to those of the untreated samples. The L^⁎, a^⁎, b^⁎, and C* values decreased significantly during 8-12 days of storage, resulting in a significant increase in ΔE, especially 400 W/10 min-treated samples. Meanwhile, the enzyme activity and rheological properties increased significantly on storage days 8-12. However, the microstructure of all samples did not change significantly during storage. Based on these results, during the storage period, the physical and chemical properties of 400 W/10 min-ultrasonic treated pumpkin juice were retained more than those in the untreated pumpkin juice. Therefore, ultrasonic treatment has broad application prospects in preserving bioactive substances and physicochemical properties and improving the storage life of fresh pumpkin juice.

Effect of Different Sterilization Methods on the Microbial and Physicochemical Changes in Prunus mume Juice during Storage

This study evaluated the pasteurization (P), ozone (O3), ultrasonic (US), and high-hydrostatic-pressure (HHP) sterilization approaches for processing of Prunus mume regarding browning factors and microorganisms, compared with non-sterilization (control check, CK) treatment. The microorganisms (total bacterial count and fungi and yeast count) in the juice were identified after different sterilization techniques, while the quality parameter changes (degree of browning, color measurements, total phenolic content, reducing sugar, ascorbic acid, 5-hydroxymethyl furaldehyde (5-HMF), amino acid nitrogen, total soluble solids (TSS), pH value) were investigated. The results indicate that P and HHP treatment reduced non-enzymatic browning while substantially impacting the color measurements, TSS, and pH, while the sterilization effect was remarkable, with a rate exceeding 90%. Furthermore, the Prunus mume juices treated with P and HHP sterilization were used as the objects, and the CK group was used as the control group. They were placed at 4 °C, 25 °C and 37 °C, respectively, and stored in dark for 15 d. Sampling and determination were carried out on 0, 3, 6, 9, 12, and 15 d, respectively. M-&-Y (molds and yeasts) were not detected in the late storage period, and no obvious microbial growth was observed during storage, indicating that P and HHP treatments could ensure the microbial safety of Prunus mume juice. P- and HHP- treated Prunus mume juice has better quality and low temperature storage is beneficial for maintaining the quality of Prunus mume juice. Therefore, P treatment or HHP treatment combined with low temperature storage could achieve a more ideal storage effect. Overall, this study conclusively established that P and HHP methods were suitable for sterilizing Prunus mume juice. These techniques minimally affected overall product quality while better maintaining the quality parameters than the untreated juice samples and those exposed to O3 and US treatment.

High Pressure Processing Applications in Plant Foods

High pressure processing (HPP) is a cold pasteurization technology by which products, prepacked in their final package, are introduced to a vessel and subjected to a high level of isostatic pressure (300-600 MPa). High-pressure treatment of fruit, vegetable and fresh herb homogenate products offers us nearly fresh products in regard to sensorial and nutritional quality of original raw materials, representing relatively stable and safe source of nutrients, vitamins, minerals and health effective components. Such components can play an important role as a preventive tool against the start of illnesses, namely in the elderly. An overview of several food HPP products, namely of fruit and vegetable origin, marketed successfully around the world is presented. Effects of HPP and HPP plus heat on key spoilage and pathogenic microorganisms, including the resistant spore form and fruit/vegetable endogenous enzymes are reviewed, including the effect on the product quality. Part of the paper is devoted to the industrial equipment available for factories manufacturing HPP treated products.

High-Pressure Processing for Sustainable Food Supply

Sustainable food supply has gained considerable consumer concern due to the high percentage of spoilage microorganisms. Food industries need to expand advanced technologies that can maintain the nutritive content of foods, enhance the bio-availability of bioactive compounds, provide environmental and economic sustainability, and fulfill consumers’ requirements of sensory characteristics. Heat treatment negatively affects food samples’ nutritional and sensory properties as bioactives are sensitive to high-temperature processing. The need arises for non-thermal processes to reduce food losses, and sustainable developments in preservation, nutritional security, and food safety are crucial parameters for the upcoming era. Non-thermal processes have been successfully approved because they increase food quality, reduce water utilization, decrease emissions, improve energy efficiency, assure clean labeling, and utilize by-products from waste food. These processes include pulsed electric field (PEF), sonication, high-pressure processing (HPP), cold plasma, and pulsed light. This review describes the use of HPP in various processes for sustainable food processing. The influence of this technique on microbial, physicochemical, and nutritional properties of foods for sustainable food supply is discussed. This approach also emphasizes the limitations of this emerging technique. HPP has been successfully analyzed to meet the global requirements. A limited global food source must have a balanced approach to the raw content, water, energy, and nutrient content. HPP showed positive results in reducing microbial spoilage and, at the same time, retains the nutritional value. HPP technology meets the essential requirements for sustainable and clean labeled food production. It requires limited resources to produce nutritionally suitable foods for consumers’ health.

High-Pressure-Induced Sublethal Injuries of Food Pathogens-Microscopic Assessment

High Hydrostatic Pressure (HHP) technology is considered an alternative method of food preservation. Nevertheless, the current dogma is that HHP might be insufficient to preserve food lastingly against some pathogens. Incompletely damaged cells can resuscitate under favorable conditions, and they may proliferate in food during storage. This study was undertaken to characterize the extent of sublethal injuries induced by HHP (300-500 MPa) on Escherichia coli and Listeria inncua strains. The morphological changes were evaluated using microscopy methods such as Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Epifluorescence Microscopy (EFM). The overall assessment of the physiological state of tested bacteria through TEM and SEM showed that the action of pressure on the structure of the bacterial membrane was almost minor or unnoticeable, beyond the L. innocua wild-type strain. However, alterations were observed in subcellular structures such as the cytoplasm and nucleoid for both L. innocua and E. coli strains. More significant changes after the HHP of internal structures were reported in the case of wild-type strains isolated from raw juice. Extreme condensation of the cytoplasm was observed, while the outline of cells was intact. The percentage ratio between alive and injured cells in the population was assessed by fluorescent microscopy. The results of HHP-treated samples showed a heterogeneous population, and red cell aggregates were observed. The percentage ratio of live and dead cells (L/D) in the L. innocua collection strain population was higher than in the case of the wild-type strain (69%/31% and 55%/45%, respectively). In turn, E. coli populations were characterized with a similar L/D ratio. Half of the cells in the populations were distinguished as visibly fluorescing red. The results obtained in this study confirmed sublethal HHP reaction on pathogens cells.

High-Pressure Processing on Whole and Peeled Potatoes: Influence on Polyphenol Oxidase, Antioxidants, and Glycaemic Indices

Polyphenol oxidase (PPO) inactivation in five whole and peeled Irish potato cultivars was investigated using high-pressure processing (HPP) at 400 MPa and 600 MPa for 3 min. PPO activity was significantly lower in most of the HPP-treated samples, while the highest PPO inactivation was observed after HPP at 600 MPa. No significant (p > 0.05) changes were observed on the total phenolic content and antioxidant activity of all the HPP-treated potatoes. Regarding individual phenolic acids, chlorogenic acid was decreased significantly (p < 0.05) in all studied varieties with a concomitant increase (p < 0.05) in caffeic and quinic acid. Similarly, ferulic acid was also increased (p < 0.05) in all studied varieties after the HPP treatment, while there was a variation in rutin and 4-coumaric acid levels depending on the cultivar and the sample type. Anthocyanins in the coloured whole potato varieties (i.e., Kerr’s Pink and Rooster), tentatively identified as pelargonidin-O-ferulorylrutinoside-O-hexoside and pelargonidin-O-rutinoside-O-hexoside, also exhibited significantly (p < 0.05) higher levels in the HPP-treated samples as opposed to those untreated. Glycaemic indices of the potatoes treated with HPP did not differ with the corresponding untreated cultivars.

Procyanidin B1 and p-Coumaric Acid from Highland Barley Grain Showed Synergistic Effect on Modulating Glucose Metabolism via IRS-1/PI3K/Akt Pathway

INTRODUCTION

Phenolic extract in highland barley grain has showed hypoglycemic effect, while little information is available about the active compounds and whether there exist additive or synergistic effect on modulating glucose metabolism.

METHODS AND RESULTS

Procyanidin B1 (PB) and p-coumaric acid (CA) are the active compounds in highland barley grain and show synergistic effect on improving glucose uptake and glycogen synthesis by upregulating glucose transporter (GLUT4) and downregulating glycogen synthase kinase-3β (GSK-3β) protein expression, respectively. The mechanism may be attributed to target insulin receptor (IRβ) and regulate insulin receptor substrate-1 (IRS-1)/phosphatidylinositol 3-kinase (PI3K)/ protein kinase B (Akt) pathway. Furthermore, PB + CA exhibits synergistic effect on restoring glucose intolerance and insulin resistance, and improving hepatic glycogen synthesis in impaired glucose tolerance (IGT) mice. The postprandial blood glucose (PBG), homeostasis model assessment (HOMA)-IR values and serum insulin contents in PB + CA-treated IGT mice with dosage of 300 mg kg^-1 BW are reversed to normal levels. Additionally, PC + CA shows additive effect on inhibiting gluconeogenesis in vitro and in vivo.

CONCLUSION

PB + CA in highland barley grain synergistically modulate glucose metabolism. These results may provide evidence of whole highland barley grain diet achieve superior effect on restoring IGT than isolated components.

Carrot Juice Consumption Reduces High Fructose-Induced Adiposity in Rats and Body Weight and BMI in Type 2 Diabetic Subjects

Nutritional intervention is a key strategy in the control and management of non-communicable diseases. Here, initially, we evaluated the effects of carrot juice (CJ) on some of the physical and biochemical parameters in rats fed with high-fructose diet, then in type 2 diabetic subjects. For the animal study, weanling male Wistar rats were given control (n = 6) or high fructose (HFr; n = 24) diet for 8 weeks. Then, the HFr group rats were subdivided into 4 groups (n = 6 in each) and continued either on HFr diet or shifted to control diet, with or without CJ (0.3 mg β-carotene) ingestion orally for 8 weeks. At the end, the ingestion of CJ reversed the HFr-induced adiposity (23 ± 1.6 vs 18 ± 1.1, P = .038), hypertriglyceridemia (182 ± 18.2 vs 90 ± 10.5 mg/dL, P<0.001), and hyperinsulinemia (81 ± 14.7 vs 40 ± 7.5 µU/mL, P = .014), while increased the retinol levels in liver (240 ± 38.4 vs 492 ± 61.2 µg/g, P = .002) and adipose tissue (1.8 ± 0.09 vs 2.5 ± 0.18 µg/g, P = .026). On the other hand, in the diabetic subjects (7 males and females each, n = 14) compared to their baseline, the daily consumption of 50 mL CJ (~2400 µg β-carotene) for 6 weeks significantly reduced the body weight (69.4 ± 4.13 vs 69.0 ± 4.09 kg, P = .014), BMI (27.4 ± 1.07 vs 27.2 ± 1.06 kg/m², P = .007), and fat% (33.4 ± 1.87 vs 31.9 ± 2.13, P = .029) with an increase in plasma β-carotene levels (0.21 ± 0.045 vs 0.45 ± 0.089 µmol/L, P = .044). Although CJ increased the glucose (145 ± 10.4 vs 165 ± 11.4 mg/dL, P = .039), insulin, and glycated hemoglobin levels remained unaltered. In conclusion, the consumption of carrot juice reversed the HFr-induced metabolic abnormalities in a rat model and decreased body weight and BMI of diabetic subjects.

Revisiting Non-Thermal Food Processing and Preservation Methods-Action Mechanisms, Pros and Cons: A Technological Update (2016-2021)

The push for non-thermal food processing methods has emerged due to the challenges associated with thermal food processing methods, for instance, high operational costs and alteration of food nutrient components. Non-thermal food processing involves methods where the food materials receive microbiological inactivation without or with little direct application of heat. Besides being well established in scientific literature, research into non-thermal food processing technologies are constantly on the rise as applied to a wide range of food products. Due to such remarkable progress by scientists and researchers, there is need for continuous synthesis of relevant scientific literature for the benefit of all actors in the agro-food value chain, most importantly the food processors, and to supplement existing information. This review, therefore, aimed to provide a technological update on some selected non-thermal food processing methods specifically focused on their operational mechanisms, their effectiveness in preserving various kinds of foods, as revealed by their pros (merits) and cons (demerits). Specifically, pulsed electric field, pulsed light, ultraviolet radiation, high-pressure processing, non-thermal (cold) plasma, ozone treatment, ionizing radiation, and ultrasound were considered. What defines these techniques, their ability to exhibit limited changes in the sensory attributes of food, retain the food nutrient contents, ensure food safety, extend shelf-life, and being eco-friendly were highlighted. Rationalizing the process mechanisms about these specific non-thermal technologies alongside consumer education can help raise awareness prior to any design considerations, improvement of cost-effectiveness, and scaling-up their capacity for industrial-level applications.

Applying Pulsed Electric Fields to Whole Carrots Enhances the Bioaccessibility of Carotenoid and Phenolic Compounds in Derived Products

We propose the application of pulsed electric fields (PEF) to carrots to obtain derived products with increased phenolic and carotenoid bioaccessibility. For this purpose, juices, purees, and oil-added purees were obtained from whole PEF-treated carrots (five pulses of 3.5 kV cm-1; 0.61 kJ kg-1). In order to obtain shelf-stable products, the effect of a thermal treatment (70 °C for 10 min) was also studied. Carrot juices exhibited the highest carotenoid (43.4 mg/100 g fresh weight) and phenolic (322 mg kg-1 dry weight) contents. However, caffeic and coumaric acid derivatives were highly sensitive to PEF. The phenolic bioaccessibility reached 100% in purees obtained from the PEF-treated carrots, whereas the further thermally treated oil-added purees exhibited the greatest carotenoid bioaccessibility (7.8%). The increase in carotenoid bioaccessibility could be related to their better release and solubilization into micelles. The results suggest that food matrix aspects apart from particle size (e.g., pectin characteristics) are involved in phenolic bioaccessibility.

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.

Centrifugal Filter-Assisted Block Freeze Crystallization Applied to Blueberry Juice

The impact of centrifugal-filter assisted block freeze crystallization (CFBFC) on the physicochemical parameters, total phenolic content (TPC), total anthocyanin content (TAC), and total flavonoid content (TFC), antioxidant activity (AA) and process parameters applied to blueberry juice was studied. Additionally, CFBFC was contrasted with gravitational BFC (GBFC) and centrifugal BFC (CBFC) techniques. For CFBFC process, the solutes values were ≈35.9 °Brix (fresh juice ≈13.8 °Brix), with a very dark red/purple color. Moreover, the bioactive components values presented a significant increase of 2.1, 2.0, 1.8, and 3.1 times compared to the initial TPC, TAC, TFC, and AA values, respectively, and these values were higher than GBFC and CBFC techniques. For efficiency, percentage of concentrate, and solute yield, CFBFC showed values close to 86%, 81%, and 0.9 (kg/kg), respectively, which were higher values than GBFC (48%, 38%, and 0.5 (kg/kg)) and CBFC (79%, 68%, and 0.7 (kg/kg)). Therefore, this research offers new benefits with the addition of the filter in the centrifugal BFC, and thus, CFBFC offers an advantage due to the better separation than GBFC and CBFC, since the filter can be designated as a second separation stage, and only one cycle is necessary to obtain high quality properties in the final solution.

Sequential Application of High-Voltage Electric Field Cold Plasma Treatment and Acid Blanching Improves the Quality of Fresh Carrot Juice (Daucus carota L.)

The study was aimed to investigate the combined effect of acid blanching (AB) and high-voltage electric field cold plasma (HVCP) on carrot juice quality. Before juice extraction, carrots were separated into three parts: control, blanched (100 °C for 5 min) with non-acidified water, and blanched with acidified water (35 g/L citric acid at pH 1.34). Carrot juice was then subjected to dielectric barrier discharge at 80 kV for 4 min. Results indicated that AB treatment significantly influenced the efficiency of HVCP. AB-HVCP resulted in antimicrobial synergism, which is an outcome of acidified NO₂^-, H₂O₂, O^-, and peroxynitrites (ONOO^-) or its precursor OH/NO₂, along with other species. In addition, plasma treatment also promotes the accumulation of coloring compounds, chlorogenic acid, and sugar contents by surface erosion of the epidermal layer, cis isomerization, rupturing of phenol-sugar and phenolic-cell matrix bonds, and depolymerized long-chain polysaccharides by cleavage of the glycoside bond. Therefore, AB-HVCP is a potential emerging hurdle strategy for fresh produce.