High Hydrostatic Pressure Processing Research Articles

High hydrostatic pressure processing of whole buckwheat grains to obtain functional gluten-free ingredients: Effect of pressure and holding time

High Hydrostatic pressure (HHP) represents an environmental-friendly and efficient non-thermal technology capable of inducing changes that can lead to functional improvements on starchy materials preserving the nutritional value of the original flours. The development of gluten-free (GF) flours and ingredients remain a challenge due to the need to improve the nutritional and techno-functional aspects of these commodities. Pre-soaked whole buckwheat (BW) grains were subjected to HHP treatment under different processing conditions: two pressure levels (300–600 MPa) and three holding times (0-5-15 min) to evaluate the techno-functional and nutritional response of the resulting flours. Significant (p < 0.05) increases in water absorption capacity and swelling capacity were observed in the flours resulting from longer treatment times (5–15 min) and the highest-pressure level (600 MPa). Higher thermal stability was also observed in the pasting profiles obtained for these flours. Flours resulting from HHP treatments at 600 MPa for 15 min also showed higher antioxidant capacity (DPPH and ORAC). The resulting flour from these processing conditions was used at different concentrations (15, 30, 50, and 70 %) in a GF bread formulation. An increase in the elastic modulus values of the doughs, the specific volume of the resulting bread and a reduction in the crumb firmness were observed in the formulations containing the BW-modified flour compared to the counterparts made with a native flour. Therefore, it can be concluded that the HHP treatment of whole buckwheat grains represents an interesting alternative for the development of ingredients with suitable technological and nutritional properties for gluten-free bakery formulations.

Donor human milk treated by high-pressure processing improves the body growth of growth-restricted mice pups.

Pasteurized human donor milk (DM) is frequently used for feeding preterm newborns and extrauterine growth-restricted (EUGR) infants. Most human milk banks performed a pasteurization of DM using the standard method of Holder pasteurization (HoP) which consists of heating milk at 62.5°C for 30 min. High hydrostatic pressure (HHP) processing was proposed to be an innovative nonthermal method to pasteurize DM. However, the effect of different modes of DM pasteurization on body growth, intestinal maturation, and microbiota has never been investigated in vivo during the lactation. We aimed to study these effects in postnatally growth-restricted (PNGR) mice pups daily supplemented with HoP-DM or HHP-DM. PNGR was induced by increasing the number of pups per litter (15 pups/mother) at postnatal Day 4 (PND4). From PND8 to PND20, mice pups were supplemented with HoP-DM or HHP-DM. At PND21, the intestinal permeability was measured in vivo, the intestinal mucosal histology, gut microbiota, and short-chain fatty acids (SCFAs) level were analyzed. HHP-DM pups displayed a significantly higher body weight gain than HoP-DM pups during lactation. At PND21, these two types of human milk supplementations did not differentially alter intestinal morphology and permeability, the gene-expression level of several mucosal intestinal markers, gut microbiota, and the caecal SCFAs level. Our data suggest that HHP could be an attractive alternative to HoP and that HHP-DM may ensure a better body growth of preterm and/or EUGR infants.

Isolation and characterization of superdormant Bacillus subtilis spores under high hydrostatic pressure at 200 MPa and 500 MPa

High hydrostatic pressure (HHP) (200 MPa/500 MPa) superdormant (SD) spores were isolated and characterized for germination and resistance properties. Compared with untreated spores, two-hundred MPa-SD spores showed germination defect with L-alanine, AGFK, dodecylamine, 200 MPa or 500 MPa. Meanwhile, they exhibited elevated resistance to 93 °C and UV254 nm with decimal reduction time (D-value) increased by 2.7 and 1.5 fold respectively, reduced resistance to 0.22 M HCl and 3.2 M H2O2 with D-value decreased by 1.4 and 1.3 fold respectively, and no change in resistance to 0.83 M formaldehyde and 0.34 M NaClO. Five-hundred MPa-SD spores showed germination defect with 500 MPa, no change in germination with L-alanine, AGFK or 200 MPa, but increased germination efficiency with dodecylamine. Accordingly, their resistance to 0.34 M NaClO and UV254 nm elevated with D-value increased by 1.8 and 1.3 fold respectively, while resistance to 93 °C, 0.22 M HCl, 0.83 M formaldehyde and 3.2 M H2O2 reduced with D-value decreased by 2, 1.4, 1.4 and 2.3 fold respectively. These properties were noninheritable as re-sporulated spores from SD spores showed identical germination behavior compared to initial untreated spores. Proteomics analysis revealed that the mechanism of SD spores' superdomancy was likely attributed to the variation of coat proteins and SASPs, and inner membrane modifications. Industrial relevanceIt has long been acknowledged that the existence of SD spores greatly limits the successful application of HHP technology in low-acid foods. The data in this work provide valuable knowledge to understand the properties of SD spores under HHP, and thus hopefully can promote developing new strategies to eliminate bacterial spores in low-acid foods during industrial HHP processing.

Exploring high hydrostatic pressure effects on anthocyanin binding to serum albumin and food-derived transferrins

This study investigated the effects of high hydrostatic pressure (HHP) on the binding interactions of cyanindin-3-O-glucoside (C3G) to bovine serum albumin, human serum albumin (HSA), bovine lactoferrin, and ovotransferrin. Fluorescence quenching revealed that HHP reduced C3G-binding affinity to HSA, while having a largely unaffected role for the other proteins. Notably, pretreating HSA at 500 MPa significantly increased its dissociation constant with C3G from 24.7 to 34.3 μM. Spectroscopic techniques suggested that HSA underwent relatively pronounced tertiary structural alterations after HHP treatments. The C3G-HSA binding mechanisms under pressure were further analyzed through molecular dynamics simulation. The localized structural changes in HSA under pressure might weaken its interaction with C3G, particularly polar interactions such as hydrogen bonds and electrostatic forces, consequently leading to a decreased binding affinity. Overall, the importance of pressure-induced structural alterations in proteins influencing their binding with anthocyanins was highlighted, contributing to optimizing HHP processing for anthocyanin-based products.

Improved properties of potato starch/myristic acid composite films via high hydrostatic pressure: The role of pressure-induced intermolecular interaction

In this study, an innovative approach was proposed to prepare potato starch/myristic acid composite film using a high hydrostatic pressure (HHP) process to improve its properties. The myristic acid/potato starch ratio in the composite films significantly increased after HHP treatment, resulting in substantial improvements in the physicochemical properties of the films. HHP-treated film presented a more uniform and smooth surface morphology, whereas the tensile strength was significantly improved. Meanwhile, water vapor permeability, water solubility, and moisture content decreased altogether. Most importantly, HHP treatments substantially enhanced the hydrophobicity of the composite film as the water contact angle increased from 33.2% to 46.2%. Raman spectroscopy and FT-IR results confirmed that HHP altered the intermolecular interaction between potato starch and myristic acid, forming more hydrogen bonds with shorter bond lengths. It led to the structural transformation from V6I complexes to V6II and V6III complexes, with relative crystallinity increased from 35.46% to 44.56%. This work provided a novel pressure-assisted method to fabricate starch/lipid biopolymer film with substantially improved hydrophobicity, thermal stability, and mechanical properties.

Matrix effect on the Effectiveness of High Hydrostatic Pressure Treatment on Antibiotic Residues

The use of antibiotics in agriculture and livestock poses health risks to consumers. Treatments such as High Hydrostatic Pressure (HHP) have been shown to reduce antibiotic and pesticide residues in food. This study aims to investigate the matrix effect on the effectiveness of HHP on hydrochloride tetracycline (HTC) and sulfathiazole (STZ) residues in spiked food matrices. The effect of viscosity, as well as carbohydrate, protein, and fat content on the effectiveness of HHP on antibiotic residues, was investigated. The studied matrices were full-fat and fat-free bovine milk and model food systems consisting of aqueous solutions of sugars, aqueous solutions of proteins, and oil in water emulsions. Model food systems were also used to study the viscosity effect. These systems consisted of aqueous solutions of honey, aqueous solutions of apple puree, and aqueous solutions of glycerol. The HHP processing (580 MPa, 6 min, 25 °C) took place under industrial conditions. For both antibiotics, the concentration of sugars and proteins was found to affect the effectiveness of treatment. The concentration of oils affected treatment efficacy only for HTC. Reduction of antibiotics by HHP was also affected by the type of carbohydrate and the viscosity. In conclusion, the composition and the viscosity of the food matrix exert a variable effect on the studied antibiotic residues reduction by HHP indicating different underlying mechanisms of the interactions between food constituents and antibiotics under the same process conditions.

Comparative study on microbiological, physicochemical and nutritional properties of whole cow milk by thermal and non-thermal processing technologies

The majority of the bioactive components in milk exhibit sensitivity to heat treatments. This research is the first systematically compare the effects of thermal (low-temperature long time pasteurization, LTLT; high-temperature short time pasteurization, HTST; ultra-high temperature, UHT; microwave-assisted heating; retort sterilization) and non-thermal (ultraviolet-C, UV-C; high hydrostatic pressure processing, HPP; filtered sterilization; high-intensity ultrasound, HIUS) treatments on the physicochemical properties and immune-active serum proteins of whole milk aliquots under the equivalent microbicidal efficacy. LTLT and HTST had little impact on whole milk. HPP at 400 MPa for 5 min was an optimal alternative to pasteurized milk in terms of equivalent microbicidal efficacy, higher nutrient retention (∼6% and 16.2% loss for IgG and lactoferrin) and fewer oxidation products (0.69 nmol/mg protein carbonyls). The serum protein denaturation of 600 MPa HPP-treated milk (79.4% and 31.36% loss for IgG and lactoferrin) was significantly higher than in pasteurized milk, but still lower than in UHT milk (97.16% and 70.85% loss for IgG and lactoferrin). Since photo-oxidation induced by high-dose irradiation was detrimental to the organoleptic properties, relying on UV-C as stand-alone replacement to pasteurization is not advisable. Combined with existing pasteurization methods, UV-C can achieve superior microbial inactivation at mild sterilization temperatures. HIUS, a promising novel tool, should be further optimized regarding the relevant standards to enable it to be used in industrial-scale processing and reproducibility. Compared with traditional thermal treatments, non-thermal strategies offer a significant reduction in the microbial load of raw milk while better preserving bioactive proteins, However, optimizing processing parameters remains essential to strike a balance between microbial inactivation and retention of active substances.

Effects of hypothermia–hypoxia pulping, high hydrostatic pressure processing, and repeat freeze–thaw cycles on the quality of raw kiwifruit puree

AbstractThis study evaluated the effects of the whole process of non‐thermal processing (hypothermia–hypoxia pulping and high hydrostatic pressure (HHP) pasteurization), different freezing methods, and repeat freeze–thaw cycles on physicochemical and nutritional quality of kiwifruit puree. Results showed that hypothermia–hypoxia treatment can retain the vitamin C, total phenol content, and antioxidant capacity of the puree better. Different pasteurization treatments can effectively kill microorganisms and improve the total phenol content and antioxidant capacity of the raw puree. Compared with thermal treatment, HHP can better retain the color, viscosity, and aroma components of the raw puree. The freezing methods have little impact on the quality of the raw puree, but peroxidase enzyme activity after quick freezing was significantly higher than that of slow freezing. Different freeze–thaw treatments had adverse effects on the quality of kiwifruit, and the damage of 25°C thawing conditions was more serious than that of 4°C thawing conditions. This research would provide new ideas for the production and storage of high‐quality kiwifruit puree and potential technical support for kiwifruit puree commercial production.Practical ApplicationsThe results of this study showed that non‐thermal processing can maintain the quality of kiwifruit puree better than traditional thermal processing, which provides a new idea for the production of high‐quality kiwifruit puree. In addition, this study suggests that temperature fluctuations should be minimized during storage to better maintain kiwifruit quality. This will provide potential technical support for the commercialization of kiwifruit puree.

Gut Microbiome and Metabolome Modulation by High-Hydrostatic-Pressure-Processed Tomato Juice.

High hydrostatic pressure (HHP) is a non-thermal pasteurization technology for the enhancement of food products' safety and quality. The components of tomato juice can be affected by HHP processing. Little is known about the effects of HHP-processed tomato juice on the gut microbiome and metabolism. Here, we performed high-throughput sequencing and metabolomics profiling to determine the critical differences in gut microbiota structure and metabolic profiles in mice administered with HHP-processed tomato juice. Tomato juice administration significantly increased the gut bacterial alpha diversity and the relative abundance of Bacteroides. The mice administered with HHP-processed tomato juice were characterized by the enrichment of Bacteroidetes, Alistieps, and Faecalibaculum compared with those administered with HTST-processed tomato juice. Moreover, HHP-processed tomato juice promoted SCFA levels, which were positively correlated with the enriched Alistieps. Our results show that HHP-processed tomato juice may drive healthy gut microbes and metabolites.

Effect of the High Hydrostatic Pressure Process on the Microbial and Physicochemical Quality of Shalgam.

The processing of shalgam requires the use of an appropriate processing technique due to yeast overgrowth. With advancements in processing technology, high hydrostatic pressure (HHP) as nonthermal and nonchemical preservation has gained attention for its potential. Response surface methodology with the Box-Behnken experimental design was used to make sense of the effects of HHP parameters, namely, pressure (100-500 MPa), temperature (20-40 °C), and time (5-15 min), on microbial and physicochemical factors (pH, total soluble solids, titratable acidity, bioactive compounds, color values). The reduction in the counts of total mesophilic aerobic bacteria, lactic acid bacteria, and yeast-mold increased proportionally with the increase of all pressure levels, application temperatures, and pressurization times (p < 0.05). Stability was maintained in pH, total solubility, and some color parameters such as L*, a*, ΔE, yellow color tone, and red color tone. All findings of the bioactive components (phenolic content, flavonoid content, antioxidant activity, and monomeric anthocyanin content) in the RSM design showed a significant change only in proportion to the square of time (p < 0.05). The optimum pressurization parameter combination of shalgam was determined as a pressure of 367 MPa, temperature of 31.9 °C, and process time of 10.5 min. Under these conditions, values of yeast and mold (Y&M) reduction, total flavonoid content (TFC), total monomeric anthocyanin contents (TMACs), titratable acidity (TA), and reducing sugar content (RSC) were obtained as 4.30 log cfu/mL, 192.89 mg QE/100 mL, 11.88 mg/100 mL, 2.41 glacticacid/L, and 6.78 mg/100 mL, respectively. In particular, the findings in the basic color parameters proved that there was no significant change in the saturated red color of the shalgam. Gallic acid, caffeic acid, chlorogenic acid, catechin, cyanidin-3-O-glucoside, malvidin-3-O-glucoside, and peonidin-3-O-glucoside derivatives are dominant phenolic and anthocyanin compounds, which are frequently found in turnip plants. No important losses in bioactive components were observed, despite changes in pressure and temperature parameters. The HHP method can be suggested to have great potential in the processing of shalgam (fermented turnip beverage) in terms of its ability to maintain the flavors, colors, and nutrients, in addition to ensuring microbiological safety when compared to other preservation methods.

Impact of non thermal techniques on millets

PurposeMillets are ancient grains, following wheat, that have been a fundamental source of human sustenance. These are nutrient-rich small-seeded grains that have gained prominence and admiration globally due to their super resilience in diverse climates and significant nutritional benefits. As millets are renowned for their nutritional richness, the demand for millet-based products increases. Hence, this paper aims in identifying the growing need for innovative processing techniques that not only preserve their nutritional content but also extend their shelf life.Design/methodology/approachIn traditional times, heat was the only means of cooking and processing of the foods, but the amount of damage they used to cause to the sensorial and nutritional properties was huge. Millets’ sensitivity toward heat poses a challenge, as their composition is susceptible to disruption during various heat treatments and manufacturing processes. To cater to this drawback while ensuring the prolonged shelf life and nutrient preservation, various innovative approaches such as cold plasma, infrared technology and high hydrostatic pressure (HPP) processing are being widely used. These new methodologies aim on inactivating the microorganisms that have been developed within the food, providing the unprocessed, raw and natural form of nutrients in food products.FindingsAmong these approaches, nonthermal technology has emerged as a key player that prioritizes brief treatment periods and avoids the use of high temperatures. Nonthermal techniques (cold plasma, infrared radiation, HPP processing, ultra-sonication and pulsed electric field) facilitate the conservation of millet’s nutritional integrity by minimizing the degradation of heat-sensitive nutrients like vitamins and antioxidants. Acknowledging the potential applications and processing efficiency of nonthermal techniques, the food industry has embarked on substantial investments in this technology. The present study provides an in-depth exploration of the array of nonthermal technologies used in the food industry and their effects on the physical and chemical composition of diverse millet varieties.Originality/valueNonthermal techniques, compared to conventional thermal methods, are environmentally sound processes that contribute to energy conservation. However, these conveniences are accompanied by challenges, and this review not only elucidates these challenges but also focuses on the future implications of nonthermal techniques.

High hydrostatic pressure is similar to Holder pasteurization in preserving donor milk antimicrobial activity.

The microbiological safety of donor milk (DM) is commonly ensured by Holder pasteurization (HoP, 62.5 °C for 30 min) in human milk banks despite its detrimental effects on bioactive factors. We compared the antimicrobial properties of DM after Holder pasteurization treatment or High Hydrostatic Pressure processing (HHP, 350 MPa at 38 °C), a non-thermal substitute for DM sterilization. We assessed lactoferrin and lysozyme concentrations in raw, HHP- and HoP-treated pools of DM (n = 8). The impact of both treatments was evaluated on the growth of Escherichia coli and Group B Streptococcus in comparison with control media (n = 4). We also addressed the effect of storage of HHP treated DM over a 6-month period (n = 15). HHP milk demonstrated similar concentrations of lactoferrin compared with raw milk, while it was significantly decreased by HoP. Lysozyme concentrations remained stable regardless of the condition. Although a bacteriostatic effect was observed against Escherichia coli at early timepoints, a sharp bactericidal effect was observed against Group B Streptococcus. Unlike HoP, these results were significant for HHP compared to controls. Stored DM was well and safely preserved by HHP. Our study demonstrates that this alternative sterilization method shows promise for use with DM in human milk banks. Antimicrobial activity of donor milk after High Hydrostatic Pressure treatment has not been clearly evaluated. Donor milk lactoferrin is better preserved by High Hydrostatic Pressure than conventional Holder pasteurization, while lysozyme concentration is not affected by either treatment. As with Holder pasteurization, High Hydrostatic Pressure preserves donor milk bacteriostatic activity against E. coli in addition to bactericidal activity against Group B Streptococcus. Donor milk treated by High Hydrostatic Pressure can be stored safely for 6 months.

Assessing the Impact of Pomegranate Peel Extract Active Packaging and High Hydrostatic Pressure Processing on Color and Oxidative Stability in Sliced Nitrate/Nitrite-Reduced Iberian Dry-Cured Loins

Our study aimed to assess the impact of active packaging with pomegranate peel extract (0.06 mg gallic acid eq./cm2) and/or high-pressure treatment (600 MPa, 7 min) on the instrumental color, lipid, and protein oxidation of Iberian dry loins formulated with reduced nitrate/nitrite levels (0, 37.5, and 150 mg/kg) during 100-day refrigerated storage (4 °C). CIE L*a*b* coordinates were measured, and malondialdehyde, carbonyls, and free thiol contents served as markers for lipid and protein oxidation. Active packaging lowered CIE L* (35.4 vs. 34.1) and a* (15.5 vs. 14.5) and increased yellowness (15.6 vs. 16.3) and hue (45.2 vs. 48.4), while pressurization increased CIE L* (33.1 vs. 36.3) and diminished a* values (16.1 vs. 13.9). Ongoing nitrate/nitrite amounts significantly influenced lipid peroxidation, protein carbonyl formation, and free thiol loss. Active packaging and high-pressure processing had varying effects on carbonyl and thiol contents. Neither pressurization nor active packaging impacted malondialdehyde formation. Pressurization enhanced the formation of 4-HNE (503 vs. 697 pg/g). Protein oxidation proved more sensitive to changes, with active packaging offering protection against protein carbonylation (15.4 vs. 14.7 nmol carbonyls/mg protein), while pressurization induced thiol loss (34.3 vs. 28.0 nmol Cys eq./mg protein). This comprehensive understanding provides essential insights for the meat industry, emphasizing the necessity for customized processing conditions to enhance color stability, lipid preservation, and protein integrity in dry-cured loin slices.

High hydrostatic pressure processing of fresh juice and a fermented beverage of black cherry (Prunus serotina)

The aim of this study was to evaluate the effect of high hydrostatic pressures (HHP) (200 MPa for 10 min, 400 MPa for 10 min, and 600 MPa for 5 min) and VAT pasteurization (60 °C for 30 min) on the microbiological, antioxidant and sensory characteristics of fresh juice and a fermented beverage of black cherry (Prunus serotina) stored for 49 days at 4 ± 1 °C. The HHP processing was effective to reduce the microbial load before storage and during the storage of the fermented beverages; however, for the reduction of the microbial load in fresh juice, a minimum pressure of 600 MPa for 5 min was necessary. At day 0, a reduction of 4.10 logarithmic cycles was achieved in samples processed by HHP and VAT pasteurization. The processed samples showed significant changes (p ≤ 0.05) in their color characteristics. All fermented beverages of black cherry had lower quantities of antioxidant activity, total phenols, flavonoids and anthocyanins. The highest antioxidant characteristics were observed in sample of black cherry processed at 600 MPa for 5 min. The black cherry VAT processed samples were the least sensorially accepted. A treatment of 600 MPa for 5 min could be enough to obtain a microbiologically safe fermented black cherry beverage stable for 49 days having similar antioxidant characteristics as those of fresh juice.

Application of physical, chemical, and biological preservation strategies and their effect on the shelf life of different types of cooked hams

AbstractImprovement of hygiene practices and process control in meat product facilities is an ongoing topic of importance. Consequently, the meat industry must explore alternatives to extend the shelf‐life of meat products. This study aimed to assess the effectiveness of chemical, biological, and physical strategies at the formulation, pre‐packaging, and post‐packaging stages, respectively, to extend the shelf‐life of cooked ham. Three strategies were tested on different formulations of cooked ham: (1) inclusion of organic acid salts with and without buffered vinegar in the formulation, (2) application of biopreservation cultures during pre‐packaging for the four developed formulations, and (3) high hydrostatic pressure processing (HPP) applied to two pork ham formulations during post‐packaging with and without buffered vinegar. The effect of these strategies was evaluated by measuring shelf life based on lactic acid bacteria (LAB) and mesophilic counts, monitoring pH kinetics, and conducting sensory evaluations focused on indicators of spoilage such as milkiness and swelling. Results revealed that the HPP strategy was the most effective, significantly extending the shelf life of cooked pork ham up to 97 days, with no significant differences observed when combined with buffered vinegar. In contrast, the use of organic acid salts with or without buffered vinegar did not significantly extend the shelf life compared to control hams without preservatives (p &gt; 0.05). Furthermore, significant variations in shelf life were found between batches and types of ham (p &lt; 0.05). Notably, the biopreservation strategy led to a reduction in shelf life reduction.Practical applicationsSliced‐packaged ham is highly susceptible to spoilage, and previous studies investigating the application of organic acid salts, biopreservation cultures, and physical interventions have demonstrated limited effectiveness in extending shelf life under industrial and Colombian market conditions. Moreover, some of these approaches have resulted in alterations to the product's sensory attributes. Consequently, there is a critical need to evaluate alternative strategies that can be easily implemented with current technology, are cost‐effective, acceptable to consumers, and can be validated in an industrial setting. Furthermore, it is crucial to investigate the potential synergistic effects of combining high hydrostatic pressure processing (HPP) with chemical interventions, such as buffered vinegar. Implementing these measures holds the potential to minimize food waste and contribute to enhancing food security. Additionally, the findings of this study present a hypothesis that can contribute to understanding the variations in spoilage between pork and turkey hams.

Allergenic risk assessment of enolase leaked from Saccharomyces cerevisiae under pressurization

High hydrostatic pressure (HHP) is widely employed in food sterilization and processing, but it can release the allergenic proteins into the food matrix, raising the risk of sensitization. In this research, the leaked allergen enolase from Saccharomyces cerevisiae after HHP-treatment was characterized and quantified by ELISA, Western-blot, and LC-MS/MS. MS2 results indicated that the amounts of leaked enolase following untreated, 300 MPa, and 600 MPa were respectively 0.0291, 0.0816, and 0.229 μg/mL. This illustrated a progressive release of the allergen under HHP. Furthermore, Molecular docking experiments demonstrated that enolase binds ARD1, GMP1 and TDH3 during the leakage process, affecting its allergenicity. The implications of these findings are noteworthy for comprehending the safety hazards of allergens in the context of HHP processing and for advocating the adoption of HHP technology in the food sector.

Effect of Ultrasound and High Hydrostatic Pressure Processing on Quality and Bioactive Compounds during the Shelf Life of a Broccoli and Carrot By-Products Beverage.

Vegetable beverages are a convenient strategy to enhance the consumption of horticultural commodities, with the possibility of being fortified with plant by-products to increase functional quality. The main objective was to develop a new veggie beverage from broccoli stalks and carrot by-products seasoned with natural antioxidants and antimicrobial ingredients. Pasteurization, Ultrasound (US), and High Hydrostatic Pressure (HHP) and their combinations were used as processing treatments, while no treatment was used as a control (CTRL). A shelf-life study of 28 days at 4 °C was assayed. Microbial load, antioxidant capacity, and bioactive compounds were periodically measured. Non-thermal treatments have successfully preserved antioxidants (~6 mg/L ΣCarotenoids) and sulfur compounds (~1.25 g/L ΣGlucosinolates and ~5.5 mg/L sulforaphane) throughout the refrigerated storage, with a longer shelf life compared to a pasteurized beverage. Total vial count was reduced by 1.5-2 log CFU/mL at day 0 and by 6 log CFU/mL at the end of the storage in HHP treatments. Thus, the product developed in this study could help increase the daily intake of glucosinolates and carotenoids. These beverages can be a good strategy to revitalize broccoli and carrot by-products with high nutritional potential while maintaining a pleasant sensory perception for the final consumer.

Mild high hydrostatic pressure processing: Effects on techno-functional properties and allergenicity of ovalbumin

The effects of mild (250–350 MPa) high hydrostatic pressures (HHP) on the technological properties of ovalbumin were studied. Thermal gels were prepared using HHP-treated ovalbumin. Their characteristics and the efficacy of HHP processing to inhibit allergenicity were evaluated. The samples treated at 250 MPa/15 min, 350 MPa/10 min and 350 MPa/15 min showed the best results for solubility and water and oil absorption capacities, respectively. Regardless of treatment duration, foaming capacity increased with pressure. The foam stability only increased significantly in the samples subjected to 350 MPa for 10 and 15 min. On the contrary, the mildest treatment yielded the highest emulsifying activity index and emulsion stability. Improved gel strength and water holding capacity were observed, particularly under 300 MPa, resulting in a maximum inhibition of allergenicity (46.75%).

Enhanced reducing sugar production and extraction for Chlorella vulgaris in mixotrophic cultivation using high hydrostatic pressure processing and ultrasound

ABSTRACT Although extraction of polysaccharides to convert reducing sugars (RS) from microalgae by acid or alkali pretreatments and enzymatic hydrolysis has been extensively studied, few reports exploring the use of high hydrostatic pressure processing (HHP) and ultrasonication (US) as emerging technologies for the extraction of sugars from microalgae biomass exist. Thus, the present study was conducted to determine the effects of mixotrophic growth and stress conditions (NaNO3 and CO2 concentration and light intensity) on RS and protein accumulation in the unicellular green alga Chlorella vulgaris in addition to optimization of the effectiveness of the sequential applications of HHP and US with dilute acid as well as simultaneous enzymatic saccharification on the production of RS from microalga cells. High light intensity, high CO2 concentration and limited nitrogen concentration promoted RS production. The maximum protein content (0.0683 mg g‒1) was achieved at 0.3 g l‒1 NaNO3 concentration, 7000 μmol photons m‒2 s‒1 and 6 l min‒1 CO2 concentration. The highest RS content of C. vulgaris after 48 h enzymatic saccharification (583.86 ± 13.23 mg g‒1) was obtained at 1% (w/w) acid concentration and 80% amplitude for 30 min with 79.4% RS yield. Combined US-assisted dilute acid pretreatment and enzymatic hydrolysis were also found to be more effective than HHP assisted dilute acid pretreatment and enzymatic saccharification. Therefore, microalgal biomass can be considered a suitable renewable feedstock used in fermentation.

Short-chain fatty acids levels in human milk are not affected by holder pasteurization and high hydrostatic pressure processing.

Sterilized donor milk (DM) is frequently used for feeding preterm infants. To date, the effect of different modes of DM sterilization on short-chain fatty acids (SCFAs) remains unknown. We aimed to quantify SCFAs in DM samples after two types of milk sterilization: the Holder pasteurization (HoP) and a high hydrostatic pressure (HP) processing. Eight pooled DM samples were sterilized by HoP (62.5°C for 30 min) or processed by HP (350 MPa at 38°C). Raw DM was used as control. Six SCFAs were quantified by gas chromatography/mass spectrometry. Compared to raw milk, both HoP and HP treatment did not significantly modulate the concentration of acetate, butyrate, propionate and isovalerate in DM. Valerate and isobutyrate were undetectable in DM samples. In conclusion, both HoP and HP processing preserved milk SCFAs at their initial levels in raw human milk.