Pasteurization Treatment Research Articles

Characterising the Concentration-Dependent Behaviour of Heat-Treated Sunflower Oleosomes at an Air-Water Interface

The behaviour of fresh and heat-treated sunflower oleosomes at the air-water interface was studied using a force tensiometer with a conventional method and a new approach based on the fresh interface formation. Oleosomes were recovered using a wet milling process and washed to produce washed oil bodies (WOB), then dispersed as rinsed-washed oil bodies (RWOB) in ultra-pure water. Thermal treatment of oleosomes at 75 °C for 5 min did not alter the quality of oleosomes so it was used as the pasteurisation treatment. All oleosome preparations, including fresh RWOB, reduced surface tension (ST) at the air-water interface. Fresh RWOB exhibited faster, and more extensive ST reduction compared to heat-treated samples (HT-RWOB). Serum phase (a protein rich phase produced as part of the oleosome purification process) analysis indicated extraneous proteins contribute to ST reduction. ST measurements using HT-RWOB showed concentration-dependent ST reduction from 0.005% to 0.1% (w/v), with minimal changes at higher concentrations. Fitting a linear model on the concentration-dependent zone and concentration-independent zone showed that the cross over happens at the concentration of 0.1% (w/v) which is regarded as the critical packing concentration (CPC, the concentration by which the interface is saturated). Colloidal instability phenomena were observed at high concentrations. Particle size measurement and micrographs of emulsions before and after ST measurement indicate significant breakage and coalescence of oleosomes at high concentrations because of the formation of multiple layers at the interface after the CPC. This paper explores the impact of these changes on the ST and suggests possible explanations.

Physicochemical and functional characteristics of egg white powder as affected by pre-treatment and drying methods

Egg white is often regarded as a high-quality protein source that contains all essential amino acids required by humans. A fresh egg in liquid form has a short shelf life, thus drying it into powder can be the best alternative for a longer short life. This research aimed to evaluate the physicochemical and functional characteristics of egg white powder (EWP) as affected by pasteurization as pre-treatment and drying methods. There were six treatments in the preparation of EWP, i.e., pasteurization, unpasteurization and combined with three drying methods (spray-, cabinet-, or freeze-drying). The physical and functional properties of EWP were determined i.e., the yield, color, water activity, bulk density, flowability, foaming, emulsification, water absorption (WAC), oil absorption capacity (OAC), and gel strength. The chemical properties i.e. moisture content, fat, ash, protein content, protein digestibility, and antioxidant activity were also determined. The results showed that pasteurization and different drying methods affected the physicochemical and functionality of EWP. Pasteurization treatment significantly increased the bulk density of EWP prepared by spray- and cabinet drying, WAC of EWP prepared by spray- and cabinet drying, gel strength of EWP prepared by spray drying, the protein content of EWP prepared by spray drying, protein digestibility of EWP prepared by spray- and cabinet drying; however, significantly decreased the aerated and tapped bulk density of EWP prepared by freeze-drying, gel strength of EWP prepared by cabinet- and freeze-drying, the protein content of EWP prepared by cabinet- and freeze-drying, protein digestibility of EWP prepared by freeze-drying, antioxidant activity of EWP prepared by spray-, cabinet-, and freeze-drying. Different drying methods significantly affected the color parameters, bulk density, gel strength, moisture content, protein content and protein digestibility. This study suggested that the best characteristic of EWP was that of unpasteurized and prepared by freeze-drying method.

Assessment of the impact of pasteurisation on protein denaturation in sheep sweet whey by asymmetrical flow field-flow fractionation according to sampling period

Whey recovery is limited in artisanal cheese manufacture. This by-product of cheese manufacture was traditionally considered as waste and is highly polluting. However, interest in the nutritional properties of native whey and its proteins has recently increased. Pretreatment is required to preserve highly perishable whey for processing. Only a few studies have focused on sheep whey, despite its considerable nutritional and technological potential. Here, we investigated the effect of heat treatment on the denaturation and formation of protein aggregates in sweet sheep whey collected in January, April and July. Two pasteurisation protocols were studied (72 °C for 1 min and 80 °C for 15 s). Microbiological quality was assessed by checking for the presence of microbes after five days of storage at 4 °C. Asymmetrical flow field-flow fractionation (AF4) coupled to UV detector, multiangle light scattering (MALS) and refractometer (dRi) is a mild, non-naturing technique for determining the extent of denaturation of whey proteins and the size of whey protein aggregates. Greater whey protein denaturation and larger whey protein aggregates were observed for the 80 °C/15 s protocol than for the 72 °C/1 min protocol, for the January and April samples. A decrease in Immunoglobulin G (IgG) content was observed after heat treatments in the samples from July but not significantly for the other proteins. Moreover, the retention times of the monomeric whey protein peaks on the AF4 fractogram were higher for this period, indicating that the proteins were larger. Microbiological testing showed that both pasteurisation treatments were sufficiently effective to ensure good sanitary quality. The pasteurisation schedule best preserving native proteins was heating at 72 °C for 1 min.

Effect of pilot-scale high-temperature short-time processing on the retention of key micronutrients in a fortified almond-based beverage: implications for fortification of plant-based milk alternatives.

The effect of thermal processing treatments on key micronutrients in fortified almond-based beverages has not been well characterized. An almond-based beverage was produced in a pilot plant, fortified with vitamin A palmitate, vitamin D2, riboflavin (vitamin B2), calcium carbonate, and zinc gluconate, and was processed using various high-temperature short-time (HTST) pasteurization treatments. Naturally present micronutrients in the base ingredients included several B vitamins (vitamin B1 [thiamin], total vitamin B3 [sum of nicotinamide and nicotinic acid], and total vitamin B6 [sum of pyridoxal, pyridoxamine, and pyridoxine]) and minerals (magnesium, phosphorus, and potassium). The prepared almond-based beverage was homogenized and thermally processed using HTST pasteurization with a temperature range from ~94 to 116°C for a constant time of 30 s. The samples were analyzed for vitamin A palmitate, vitamin D2, target B vitamins (thiamin, riboflavin, total vitamin B3, and total vitamin B6), and minerals (magnesium, phosphorus, potassium, calcium, and zinc). The results showed that amounts of vitamin A, vitamin D2, riboflavin, and total vitamin B6 did not significantly (p > 0.05) change after the HTST treatments, whereas thiamin significantly (p < 0.05) decreased by 17.9% after HTST treatment at 116°C. Interestingly, total vitamin B3 content significantly (p < 0.05) increased by 35.2% after HTST treatment at 116°C. There was no effect of processing on the minerals that were monitored. The results from this study indicate that the majority of key micronutrients assessed in this study are stable during HTST processing of an almond-based beverage and that fortification of plant-based milk alternatives may be a viable process to enhance the micronutrient content consumers receive from these products.

Differential Digestive Stability of Food-Derived microRNAs: The Case of miR-30c-5p and miR-92a-3p in Polyfloral Honey.

Dietary microRNAs (miRs) represent a new area in food science. Although they have been found in many foods, including honey, more research is needed about their stability and fate during digestion. Hence, this study aimed to analyze the digestive stability of two selected miRs in honey. We extracted miR-92a-3p and miR-30c-5p from pasteurized and unpasteurized forms of polyfloral honey using two different methods and kits: a column-based manual method and a phenol-free semi-automated magnetic-bead-based method. The latter option was used for the subsequent analysis of samples according to the INFOGEST static in vitro digestion protocol. Also, the honey samples were examined for exosome-like particles using dynamic light scattering. Although the expression levels of both miRs were significantly lower following intestinal digestion, we found a difference in the resilience of the miRs to gastrointestinal conditions, with miR-30c-5p being relatively stable compared to miR-92a-3p following digestion, regardless of the honey's pasteurization treatment. Moreover, there was marked heterogeneity in the extracellular vesicle profile of the pasteurized sample. We identified the presence of two broadly conserved miRs in honey: miR-92a-3p and miR-30c-5p. Despite honey exhibiting high digestibility, miR-92a-3p was less resilient than miR-30c-5p, demonstrating considerable resistance under gastrointestinal conditions. Although further research is needed, the results obtained from this study may represent a starting point for utilizing honey as a source of exogenous miRNAs for preventive strategies and more "natural" treatments.

Study on the synergistic action of β-cyclodextrin and sodium caseinate to stabilize the seal oil pickering emulsion

In order to explore the synergistic action of β-cyclodextrin (β-CD) and sodium caseinate (SC) to stabilize the seal oil Pickering emulsion. Seal oil emulsions were prepared by β-CD (β-CD-E), SC (SC-E) and hybrid particles (β-CD@SC-E). Appearance and microscopic morphological analysis, particle size, ζ-potential and viscosity were used to characterize the emulsions. Droplets in emulsion stabilized by the hybrid particles were evenly, with smallest particle size (16.31 μm), largest absolute ζ-potential (27.85 mV) and higher apparent viscosity. Then, stability of the emulsions was evaluated by storage stability, centrifugation stability, pasteurization stability and salt stability. The results showed the appearance, microscopic morphology, particle size, creaming index (CI) of β-CD@SC-E were the least affected after storage, centrifugation, pasteurization and different salt concentration treatment. The interaction analysis indicated that blue shift happened in the maximum absorption wavelength, amide I of β-CD@SC. The α-helixes in β-CD@SC transformed to the β-fold and significant changes occurred in the crystal form and microstructure of β-CD@SC. All these results indicated that self-assembly occurred during the binding of β-CD and SC, which changed their original structures and enhanced their emulsification performance. Besides, hydrogen bonding and hydrophobic interaction played the vital roles during the self-assembly.

Kiwi (Actinidia deliciosa) juice as a natural inhibitor of the enzymatic activity of sugarcane juice, insights from experimental assessment and molecular docking analysis

The present work evaluated kiwi juice addition alongside pasteurization (at 85 °C for 5 min) or microwave treatment (for 3 min) on the quality improvement of sugarcane juice. The juice was treated in the presence of kiwi juice (0–8%), and its physicochemical properties and microbial load were compared with raw juice. The study also highlighted the key enzymes causing sugarcane juice discoloration, peroxidase (POD) and polyphenol oxidase (PPO), by quantifying kiwi juice constituents using GC–MS and monitoring their effects by molecular docking. Kiwi addition considerably raised (p < 0.05) acidity, ascorbic acid (54.28%), and phenolic compounds (32%), and decreased the POD and PPO activity of raw cane juice. Pasteurization in the presence of kiwi, rather than microwave treatment, has significantly (p < 0.05) increased the phenolic compounds and reduced POD and PPO activities until barley was detected. Molecular docking revealed that heptacosane, oleic acid, and melezitose are the primary kiwi components responsible for enzyme inactivation.

Investigation of the formation of furfural compounds in apple products treated with pasteurization and high pressure processing

The thermal treatment carried out in the processing of apple products is very likely to induce Maillard reaction to produce furfurals, which have raised toxicological concerns. This study aimed to elucidate the formation of furfural compounds in apple products treated with pasteurization and high pressure processing (HPP). The method for simultaneous determination of five furfural compounds including 5-hydroxymethyl-2-furfural (5-HMF), furfural (F), 4-hydroxy-2,5-dimethyl-3(2H)-furanone (HDMF), 2-acetylfuran (FMC), and 5-Methyl-2-furfural (MF) using high performance liquid chromatography equipped with diode array detector (HPLC-DAD) was successfully developed and validated. All five furfurals exhibited an increasing trend after the pasteurization treatment of apple clear juice, cloudy juice, and puree. 5-HMF, F, FMC, and MF were increased significantly during the precooking of apple puree. Whereas there was no significant change in the furfurals formation after apple products treated with high pressure processing (HPP) with 300 MPa and 15 min. Based on the variation of the fructose, glucose and sucrose detected in apple products after thermal treatment, it revealed that the saccharides and thermal treatment have great effect on the furfural compounds formation. The commercial fruit juice samples with different treatments and fruit puree samples treated with pasteurization were also analyzed. Five furfurals were detected more frequently in the fruit juice samples treated with pasteurization or ultra-high temperature instantaneous sterilization (UHT) than those treated with HPP. 5-HMF and FMC were detected in all fruit puree samples treated with pasteurization, followed by F, MF, and HDMF with the detection rate of 79.31 %, 72.41 %, and 51.72 %. The results could provide a reference for risk assessment of furfural compounds and dietary guidance of fruit products for human, especially for infants and young children. Moreover, moderate HPP treatment with 300 MPa and 15 min would be a worthwhile alternative processing technology in the fruit juice and puree production to reduce the formation of furfural compounds.

Effect of pulsed electric field processing on microbial and enzyme inactivation in blended plant-based milk alternatives: A case study on a microbial challenge test for a non-presterilized oat-based beverage enriched with pea protein

Microbial and enzyme inactivation by pulsed electric field (PEF) treatment was assessed in a blended plant-based milk alternative (PBMA) containing oats and pea protein without the application of presterilization. This was conducted to investigate a novel approach that permits PEF process validation for PBMA containing heat-labile components (protein and starch). Continuous PEF processing at moderate field strengths (9–10 kV/cm) combined with mild preheating (30–45 °C) for 25 s was applied over a range of specific energy inputs (77–245 kJ/L). Selective plating permitted bacterial enumeration of inoculated surrogate organisms, despite the presence of natural microbial contaminants in the non-presterilized product. A minimum 5-log reduction of inoculated surrogates Escherichia coli and Listeria innocua alongside native microbiota was identified after preheating to 35–45 °C followed by PEF at 192–215 kJ/L. α-amylase activity was reduced by up to 89% during a similar PEF treatment (205 kJ/L, 40 °C preheating). Overall, continuous PEF combined with mild preheating temperature was shown to achieve microbial inactivation in the pea protein enriched PBMA in compliance with current food safety regulations. Industrial relevancePresterilization is typically applied prior to conducting microbial challenge testing on food products to validate novel pasteurization treatments according to current regulatory requirements that a minimum 5-log reduction of relevant inoculated food pathogens must be achievable. However, for a variety of blended PBMA containing heat-labile proteins, presterilization is not advisable as the occurrence of irreversible changes in the product quality linked to protein coagulation and phase separation will affect the inactivation efficacy during subsequent microbial challenge testing. Hence, an alternative approach is presented utilizing a non-presterilized PBMA and thorough microbiological analysis, combining non-selective and selective plating techniques. This allows an identification of PEF treatment parameter with a minimum 5-log reduction of inoculated surrogate organisms alongside naturally present microbial contaminants. This may serve as a valuable guideline for stakeholders in the food industry when addressing the efficacy of novel preservation treatments such as PEF in PBMA products with similar heat-induced product stability challenges.

Effect of pasteurization, dehumidification, refrigeration and maturation on the composition, quality and acceptability of Scaptotrigona depilis honey

Honey from stingless bees has parameters that are different from those produced by Apis mellifera. These differences have led to studies of honey conservation techniques. In this context, it is necessary to evaluate whether the use of different conservation processes impacts the quality and chemical composition of this type of honey. The aim of this study was to conduct sensory analysis and determine the chemical profile, quality, and antioxidant activity of S. depilis honey subjected to different conservation processes. The physicochemical characteristics were determined in the fresh sample (time-point zero sample) and after freezing, pasteurization, dehumidification and maturation for 180 days. The reducing sugar, apparent sucrose, total acidity, moisture, water-insoluble solids, minerals, diastatic activity, Brix, color and hydroxymethylfurfural (HMF) levels were determined. These samples were also evaluated for their volatile composition and sensory aspects. After 180 days, the processed honeys showed changes in the phenolic content, and dehumidification was the treatment that most interfered with the phenolic content of the samples. The physicochemical properties that presented significant differences were the acidity, moisture, diastatic activity and color for the matured honey and the HMF levels in the dehumidification and pasteurization treatments. The main volatile compounds differed in each treatment in relation to the untreated honey. The sensory acceptance test showed significant differences for some of the attributes evaluated and the preference of consumers was for the untreated honey.

A review on the safety of growth factors commonly used in cultivated meat production.

Growth factors are commonly added to cell culture media in cellular agriculture to mimic the endogenous process of proliferation and differentiation of cells. Many of these growth factors are endogenous to humans and known to be present in the edible tissues and milk of food animals. However, there is little or no information on the use of growth factors intentionally added in food production before the advent of cultivated meat. Ten commonly used growth factors have been reviewed to include information on their mode of action, bioavailability, occurrence in food and food animals, endogenous levels in humans, as well as exposure and toxicological information drawn from relevant animal studies and human clinical trials with a focus on oral exposure. In addition, a comparison of homology of growth factors was done to compare the sequence homology of growth factors from humans and domestic animal species commonly consumed as food, such as bovine, porcine, and poultry. This information has been gathered as the starting point to determine the safety of use of growth factors in cultivated meat meant for human consumption. The change in levels of growth factors measured in human milk and bovine milk after pasteurization and high-temperature treatment is discussed to give an indication of how commercial food processing can affect the levels of growth factors in food. The concept of substantial equivalence is also discussed together with a conservative exposure estimation. More work on how to integrate in silico assessments into the routine safety assessment of growth factors is needed.

Kinetic modelling of anthocyanins and vitamin C degradation in a maqui-citrus beverage during storage for different sweeteners and pasteurization treatments

Kinetic models to describe the degradation of anthocyanins (first-order model) and vitamin C (system of ordinary differential equations) in a novel beverage, has been used as a tool to identify the most relevant variables for the degradation kinetics and to support shelf-life estimation. The models were based on an empirical dataset, accounting for the effect of a prior processing treatment (HHP at 400 MPa- 180s; HHP at 600 MPa-180s; thermal treatment at 85 °C for 15s), storage temperature (4 or 20 °C), and the use of two different sweeteners (sucralose or stevia). Using model selection (based on AIC), we conclude that the degradation kinetics depends on a complex combination of process and product parameters. A strong temperature dependence on anthocyanins and vitamin C was observed during pasteurization. Products treated by HHP resulted in higher vitamin C concentrations during storage than those thermally treated. Finally, an interaction with the sweetener resulted in a slight stabilization of bioactive compounds. In conclusion, this study demonstrates the complexity of the degradation process of bioactive compounds in these beverages, advocating that nonlinear kinetic models serve as a tool to identify the most relevant parameters, ultimately supporting product formulation and shelf life estimation.

Study of the effects of pasteurization and selected microbial starters on functional traits of fermented table olives

Table olives are one of the most known fruit consumed as fermented food, being a fundamental component of the Mediterranean diet. Their production and consumption continue to increase globally and represent an important economic source for the producing countries. One of the most stimulating challenges for the future is the modernization of olive fermentation process. Besides the demand for more reproducible and safer production methods that could be able to reduce product losses and potential risks, producers and consumers are increasingly attracted by the final product characteristics and properties on human health.In this study, the contribution of microbial starters to table olives was fully described in terms of specific enzymatic and microbiological profiles, nutrient components, fermentation-derived compounds, and content of bioactive compounds. The use of microbial starters from different sources was tested considering their technological features and potential ability to improve the functional traits of fermented black table olives.For each fermentation assay, the effects of controlled temperature (kept at 20 °C constantly) versus not controlled environmental conditions (oscillating between 7 and 17 °C), as well as the consequences of the pasteurization treatment were tested on the final products. Starter-driven fermentation strategies seemed to increase both total phenolic content and total antioxidant activity. Herein, among all the tested microbial starters, we provide data indicating that two bacterial strains (Leuconostoc mesenteroides KT 5-1 and Lactiplantibacillus plantarum BC T3-35), and two yeast strains (Saccharomyces cerevisiae 10A and Debaryomyces hansenii A15-44) were the better ones related to enzyme activities, total phenolic content and antioxidant activity. We also demonstrated that the fermentation of black table olives under not controlled environmental temperature conditions was more promising than the controlled level of 20 °C constantly in terms of technological and functional properties considered in this study. Moreover, we confirmed that the pasteurization process had a role in enhancing the levels of antioxidant compounds.

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.

Optimization of bioactive components of ultrasound treated white grape juice

Grapes are among the most commonly produced fruits worldwide, thanks to their ease of cultivation in terms of climate and soil requirements. Owing to their abundant vitamins, bioactive compounds and minerals incorporating them into one’s diet is advised for promoting human health. The bioactive components of ultrasound-treated white grape juice were optimised by response surface methodology (RSM). In addition, untreated white grape juice (C-WGJ), ultrasound treated white grape juice (U-WGJ) and thermally pasteurized white grape juice (P-WGJ) samples were compared for total phenolics compound (mg GAE/L), total flavonoids (mg CE/L) and DPPH (% Inhibition) parameters. The scientific investigation employed RSM, a widely favored approach. During the study, ultrasound process parameters such as amplitude (40, 50, 60, 70 and 80%) and duration (2, 4, 6, 8 and 10 minutes) were manipulated. The responses to the process application were assessed through analyses of total phenolic content (TPC), total flavonoid content (TFC) and DPPH (1,1-Diphenyl-2-Picryl Hydrazyl). The model achieved commendably high R2 values following optimization through RSM. One-way ANOVA for DPPH value, TFC and TPC of samples, both amplitude and duration exhibited statistically significant effects (p&amp;lt;0.001). The effectiveness of ultrasound treatment in increasing bioactive components in untreated white grape juice is higher than thermal pasteurization treatment. Through the optimization process, the best bioactive values for white grape juice were achieved, measuring 42.3 mg CE/L for TFC, 55.5% inhibition for DPPH and 440.3 mg GAE/L for TPC. Ultrasound applied to white grape juice proved to be more effective in preserving and enhancing bioactive compounds than thermal pasteurization. Consequently, the findings suggest the need for further investigations to assess the impacts of both thermal pasteurization and ultrasound technology on additional quality parameters of white grape juice.

Effects of Thermosonication on the Antioxidant Capacity and Physicochemical, Bioactive, Microbiological, and Sensory Qualities of Blackcurrant Juice.

This study investigated the effects of thermosonication (TS) on the quality of blackcurrant juice, along with its physicochemical properties, bioactive compounds, antioxidant capacity, and microbiological and sensory qualities. The treatments included raw juice (RJ), pasteurized juice (90 °C, 1 min, PJ), and thermosonicated juice (480 W, 40 kHz at 40, 50, or 60 °C, for 10, 20, 30, or 40 min, TJ). The results indicated that the effects of pasteurization and thermosonication on the pH, total soluble solids, and titratable acidity of the juice were not significant (p > 0.05). However, the cloudiness, browning index, and viscosity were significantly increased (p < 0.05), and the color properties of the blackcurrant juice were improved. The total phenolic, flavonoid, and anthocyanin contents of TJ (treated at 50 °C for 30 min) were increased by 12.6%, 20.9%, and 40.4%, respectively, and there was a notable decline in ascorbic acid content after the pasteurization treatment, while the loss was minor in all TJ samples compared with RJ. The scavenging ability of 1,1-diphenyl-2-pyridyl and hydroxyl radicals increased to 52.77% and 50.52%, respectively, which were significantly (p < 0.05) higher than those in the RJ and PJ samples. In addition, both pasteurization and thermosonication resulted in a significant (p < 0.05) reduction in microbial counts, while there were no significant (p > 0.05) differences in the sensory parameters compared with the RJ samples. In conclusion, this study suggests that TS is an effective method that can be used as an alternative to pasteurization to improve the quality of blackcurrant juice.

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.

Influence of Pasteurisation (Conventional vs. Radiofrequency) and Chill Storage on Retention of Ascorbic Acid, Tocopherol and Carotenoids in Salmorejo.

Salmorejo, a Mediterranean tomato-oil puree, is considered a dietary source of antioxidant vitamins C and E and carotenoids lycopene and β-carotene, the latter endowed with provitamin A activity. However, these antioxidants can be degraded in oxidation reactions catalysed or not by enzymes during pasteurisation and storage treatments used to stabilise the salmorejo before consumption. Due to its better penetration, the use of dielectric heating by radiofrequency (RF) may improve results of pasteurisation in this product. The objective was to assess the effects of pasteurisation temperature (70-100 °C, at 5 °C intervals) and storage time (0-5 months, at one-month intervals) on levels of ascorbic acid, α-tocopherol and carotenoids and antioxidant capacity (AC) in salmorejo pasteurised (over 10 s) by conventional (CH) or RF continuous heating. Two successive experiments were conducted to select an adequate pasteurisation temperature for use in the shelf-life study. Pasteurisation upon tested conditions allows a good retention of salmorejo antioxidants. Either CH or RF pasteurisers can be used with similar results. Vitamin C (L-ascorbic + dehydroascorbic acids) was more abundant (15-19 mg 100 g-1) than carotenoids (0.9-2.6 mg 100 g-1) (all-trans + cis lycopene and β-carotene) and α-tocopherol (0.8-1.2 mg 100 g-1) in the pasteurised product. Using excessively low temperatures (70 °C) resulted in partial losses of the three antioxidants, possibly due to oxidase residual activities. Intensifying thermal treatment improved this issue with minor losses of the thermolabile vitamin C and increased carotenoid content. Using a suitable temperature (80 °C) did not prevent most vitamin C from being degraded by the first month, while α-tocopherol, and, to a lesser extent, carotenoids, showed good retention levels during shelf life under refrigeration. Vitamins C and E and carotenoids, either by degradation, regeneration or releasing, likely contribute to the AC in salmorejo. Phenolic antioxidant response, radical-scavenging activities and redox potential values confirmed this finding. The pasteurised-chilled salmorejo shows good antioxidant properties with potential health implications, a positive nutritional aspect for consumers of this tomato-oil homogenate. The losses of antioxidants and AC due to pasteurization would be of little relevance compared to the losses accumulated during shelf life.

Phytochemicals, antioxidant capacities and volatile compounds changes in fermented spicy Chinese cabbage sauces treated by thermal and non-thermal technologies

To extend shelf life of fermented spicy Chinese cabbage sauce at room temperature, the effects of electron beam irradiation (EBI), high pressure processing (HPP), pasteurization (PT) and autoclave sterilization (AS) treatments on the colony counts of Lactobacillus plantarum, phytochemicals, antioxidant activities and volatile compounds were investigated. Results showed that thermal and non-thermal treatments could significantly decrease the colony counts of Lactobacillus plantarum, in which EBI and AS treatments inactivated Lactobacillus plantarum thoroughly. EBI and HPP treatments were superior to PT and AS treatments in terms of volatile compounds, bioactive compounds and antioxidant activities. The total contents of volatile compounds in sauces treated by EBI and HPP were significantly increased by 43.92%–61.87% and 71.53%–84.46%, respectively, and the new formed substance 2,3-butanedione endowed sauces with sweet and creamy aroma. In addition, HPP treatment improved the extractable contents of total phenolics and carotenoids, retained capsicum red pigment content, and significantly enhanced antioxidant capacities of sauces. Sauce treated by HPP at 200 MPa exhibited the highest total carotenoid content, DPPH radical scavenging activity and FRAP, increasing by 9.27%, 2.24% and 16.13%, respectively, compared with CK. EBI treatment exhibited higher total phenolic content and FRAP, which positively depended on the dose. Therefore, HPP and EBI treatments were suggested as potential technologies to improve shelf-life stability and volatile compounds of fermented spicy Chinese cabbage sauce.

Chemical and Physical Properties of Bovine Colostrum and the Effect of some Pasteurization Treatments on Them

This study estimated the chemical composition, physical properties, vitamins, and minerals in bovine colostrum samples and studied the effect of pasteurization at 63 °C / 30 minutes (T2) and 72 °C / 15 seconds (T3), compared to an unpasteurized sample (T1), on chemical properties (moisture, protein, fat, lactose, ash), physical properties (pH, density, viscosity), and vitamin and mineral concentrations. Pasteurization at 72 °C/15 sec more effect. T2 and T3 have 75.91% and 75.81% moisture, respectively, compared to T1’s 76.49%. T2 and T3 vs T1. T2 and T3 treatments had 12.38% and 12.24% protein, respectively, compared to 12.53% for T1. T1 had 5.71% fat, whereas T2 and T3 had 5.83% and 5.92%, respectively. T1 had 3.12% lactose, whereas T2 and T3 had 3.43% and 3.50%, respectively. T2 and T3 had 2.45% and 2.53% ash, respectively, whereas T1 had 2.15%. The pH values of T2, T3, and T1 were 6.11, 6.14, and 5.97, respectively, indicating that T2 and T3 pasteurization treatments affect the physical properties of colostrum. Density was 1.117 g/cm3 in T2 and 1.172 in T3, and 1.084 in T1. T1, T2, and T3 have viscosities of 16.71 CP, 26.47 CP, and 30.48 CP, respectively. Vitamins and minerals were high in colostrum samples on the first day of birth, but pasteurization treatments T2 and T3 decreased the concentration of fat-soluble vitamins A, E, D, and K and water-soluble B2 and B12 compared to unpasteurized. Pasteurization treatments T2 and T3 significantly decreased calcium and phosphorus concentrations compared to unpasteurized, although magnesium, iron, zinc, and sodium were unaffected.