Pasteurization Temperature Research Articles

Preparation of mayonnaise with excellent thermal and storage stability from egg yolk-amino acid complex: Rheology, interfacial property, microstructure and lutein delivery.

In this paper, egg yolk-amino acid (betaine or proline) complex was prepared at different pasteurization temperatures (68, 72 and 76 °C). Then complexes were applied to stabilized mayonnaise emulsion system. The results demonstrated that liquid egg yolk (LEY) protein structure gradually aggregated, molecular flexibility increased by 5 %, interfacial tension and intermolecular force enhanced remarkably with growth of pasteurization temperature. Compared with LEY, egg yolk-amino acid complex exhibited a more flexible structure with lower interfacial tension and superior molecular wettability. Complexes stabilized mayonnaise emulsion displayed excellent rheological property, homogeneous droplet distribution, smaller average particle size and higher (about 10 °C) thermal denaturation temperature (Td). In terms of thermal stability, oil binding capacity (OBC) of heated betaine mayonnaise (HBM) and heated proline mayonnaise (HPM) was approximately 20 % higher than that of heated control mayonnaise (HCM). Notably, the group of HBM thermal stability was generally excellent. During storage, mayonnaise might be an intermediate unstable state before emulsion breakage. In vitro digestion results illustrated that bioaccessibility of lutein delivered by BM-72 and PM-72 was 48.9 % and 37.0 % higher than CM-72, respectively. The results will provide reference for preparation of mayonnaise by egg yolk-amino acid complex as a carrier to deliver fat-soluble substances to improve bioaccessibility.

Modeling of Bacillus cereus evolution in pasteurized cow milk locally distributed at point of sale: a case of three companies in Tlemcen region, Algeria

Bacillus cereus is among the most hazardous bacteria that could reduce the shelf life of pasteurized milk and could threaten consumers’ health. These bacteria groups are known for their heat resistance and their ability to produce two types of toxins, diarrheic and emetic. This study aimed to enumerate the B. cereus in raw cow’s milk collected from three companies in the Tlemcen region, then modeled, based on a probabilistic approach, their evolution throughout the process, split into six steps, until the point of sale. At first, the analysis of 242 samples on MYP medium, shows a high prevalence between 92% and 98% of B. cereus with variable concentrations among the three companies. Throughout the storage of milk at refrigeration temperatures (2°C, 4°C and 5°C), no growth of B. cereus was estimated. Otherwise, the pasteurization process reduces the contamination level depending on pasteurization temperature as for company A, the mean concentration decreases from 1.53 log CFU/mL to 1.07 log CFU/mL. In this study, the distribution step at ambient temperature changes significantly the B. cereus concentration to reach a critical concentration during July and August. In conclusion, the quality of raw cow milk must be controlled before reception on the farm and the cold chain must be maintained throughout all process points until consumption.

Underlying mechanism of the microwave non-thermal effect as additional microbial inactivation on Clostridium sporogenes at pasteurization temperature level

Microwave processing can induce non-thermal effects that can inactivate additional levels of microorganisms at pasteurization temperature level (80–100 °C). The objective of this study was to investigate the mechanism behind the non-thermal effects of microwaves on vegetative cells of Clostridium sporogenes. Cell membrane damage were assessed through nuclear fluorescent dyes and by measuring nuclear acid and protein leakage. The results showed that microwave non-thermal effects and conventional water bath treatment resulted in similar nuclear acid leakage. However, microwave non-thermal effects inflicted more severe damage to the cell membranes of Clostridium sporogenes, resulting in increased protein leakage from both the inner of the cell and the cell membrane (A260 = 0.25 vs. 0.18). Consequently, it can be inferred that the inactivation of additional Clostridium sporogenes by microwave non-thermal effects is primarily attributed to the disruption of cell membranes induced by alternating electromagnetic fields, and this phenomenon is further potentiated at elevated temperatures.

Preliminary study of on-board handling of the blue swimming crabs in fisheries fleet

Abstract The operation of the Blue Swimming Crab (BSC) fleet is one day trip not far from the coast, that the handling activity of BSC was carried out on land. Target fishing grounds in waters more than 30 meters depth. Preliminary assessment was carried out to determine the type of vessel, cooling system, and handling by steaming at pasteurization temperature, and BSC storage in order to improve the quality of BSC. The components of the BSC fishing facility unit that will be designed can be feasible and suitable for operational more than 3 up to 7-day trips in deeper waters and farther from the coast.

Advantages of UHT in retaining coconut milk aroma and insights into thermal changes of aroma compounds

Coconut milk products are susceptible to bacterial damage, necessitating sterilization methods that often compromise nutrient and aroma integrity. This study investigates the effects of different thermal sterilisation methods on coconut milk aroma using headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS) and headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS). We assessed the impact of pasteurisation (PAS, 70 °C, 25 min), high-temperature sterilisation (HTS, 121.1 °C, 15 min), and ultra-high temperature sterilisation (UHT, 130 °C, 5 s) through clustered heat maps and correlation analyses. Significant differences were observed (p < 0.05), with 37 and 52 substances detected by HS-GC-IMS and HS-SPME-GC-MS, respectively, identifying 12 key aroma compounds. UHT treatment primarily reduced 8 acids, maintaining a compositional structure and sensory profile similar to raw coconut milk. PAS and HTS treatments decreased the sensory intensity of overall coconut milk aroma, creamy, and floral notes, correlating with the presence of 2-heptanol, nonanal, 4-methylvaleric acid, and 2-tridecanone. These methods increased cooked notes, associated with 5-methyl-3-heptanone, 3-butyn-1-ol, hydroxyacetone, and acetoin. Rancidity was linked to acids such as isobutyric acid, isovaleric acid, and heptanoic acid, with high temperatures effectively reducing these compounds. Prolonged temperature changes in PAS and HTS accelerated lipid oxidative degradation and the Maillard reaction, involving free fatty acids in the formation of alcohols, aldehydes, esters, and lactones. These findings provide a theoretical basis for studying coconut milk flavour deterioration.

Heat resistance of Lactobacillus brevis, Pediococcus acidilactici and Enterococcus faecium in buffer (pH 4), alcoholic and alcohol-free beer

Why was the work done: To measure the heat resistance of three vegetative bacteria in buffer (pH 4), alcoholic and alcohol-free beer. To verify that Pediococcus acidilactici ATCC 8042 and Lactobacillus brevis BSO 566 are as heat resistant as previously reported and to establish if Enterococcus faecium NRRL B-2354 could have application in validation studies for the pasteurisation of beer. How was the work done: : The heat resistance of L. brevis, P. acidilactici and E. faecium in buffer, alcoholic and alcohol-free beer was determined using two approaches - capillary test tubes and flask method. What are the main findings: E. faecium was the most heat resistant microorganism in all three liquids. D values were significantly greater, and z-values were similar or significantly greater than the corresponding values of L. brevis and P. acidilactici. Why is the work important: E. faecium is used in the food industry as a pathogenic surrogate for the validation of thermal and non-thermal processes. The work reported here suggests that E. faecium can also be used for the validation of pasteurisation of beer. Its high z-value suggests that at higher pasteurisation temperatures (&gt;65°C) it may be more resistant than yeast ascospores and could therefore be used as an indicator for flash pasteurisation.

Effect of pasteurization time and temperature on the physico-biochemical properties of soursop (Annona muricata L.) juice

This study aimed to determine the effect of pasteurization time and temperature on soursop juice characteristics. Soursop (Anonna muricata L.), a climacteric fruit, is a high source of natural antioxidants and contains polyphenol oxidase (PPO) enzyme, which causes browning and can reduce the phenol content in fruit which can reduce antioxidant activity. The pasteurization process was carried out to inactivate PPO in soursop juice production. Soursop juice was prepared from soursop fruit pulp pasteurized at temperatures (56, 62, 68, 74, and 80 oC) for various pasteurization times (5, 10, and 15 minutes). Time and temperature of pasteurization had a significant effect (ρ &lt; 0.05) on physical characteristics (Total Soluble Solid/TSS, viscosity, pH, and colour), polyphenol oxidase enzyme activity, antioxidant activity, and microbial population. Pasteurization at 62 ˚C for 5 minutes can maintain antioxidant activity with the greatest total phenol of 85.45 ± 3.5 mg GAE/100 g, total flavonoid of 71.38 ± 6.9 mg QE/100 g, and antioxidant activity of 76.91 ± 0, 33%. Pasteurization at 80 ˚C for 15 minutes can reduce the total number of bacteria from 350 ± 24 CFU/mL to 54 ± 22 CFU/mL, which has a TSS value of 13.73 ˚brix, viscosity of 928.67 mPa, pH of 4.40, a total colour change of 0.556, and has the lowest PPO enzyme specific activity of 0.0005 U/mg with enzyme inactivation of 93%.

Characterization of Egg White Lysozyme from Local Duck Mojosari and Alabio

Lysozyme, a natural antibacterial, has potential use in several applications. Generally, it is obtained from chicken egg whites. However, the idea of using local duck eggs as a source of lysozyme is not wellknown. This study aimed to isolate and purify the egg white of Mojosari and Alabio ducks to characterize lysozyme. Additionally, the study analyzed the effect of temperature treatment on lysozyme enzymatic activity. Three different temperature treatments were used: Low Temperature Long Time (63 ℃, 30’), High Temperature Short Time (72 ℃, 15”), and sterilization (121 ℃, 15’). The Amberlite resin cation exchange chromatography method was successfully used to isolate and purify Mojosari and Alabio duck egg whites, achieving purity levels of 94.92-96.09%. The presence of lysozyme was confirmed by the existence of bands that were primarily composed of lysozyme. The results showed that each aspect of the characteristics of lysozyme and enzymatic activity were significantly affected (p&lt;0.05) by the type of egg white. Enzymatic activity indicated that Alabio duck lysozyme was thermosensitive and could only survive at LTLT temperature, while Mojosari duck lysozyme could survive at LTLT and HTST pasteurization temperatures. However, both lysozymes did not survive the sterilization temperature.

Research on the production of bottled chili sauce added on nisin to reduce pasteurization temperature and improve quality, ensuring food hygiene and safety

Bottled chili sauce products are currently quite popular on the market and to preserve them for a long time, the product needs to be supplemented with some preservative additives.&amp;nbsp;With the desire to produce pasteurized bottled chili sauce products with a long shelf life with&amp;nbsp;natural preservative ingredients, having high sensory quality in terms of color, structure, and&amp;nbsp;high nutritional value, the study chose to add nisin (food additive E234) with a content of&amp;nbsp;200 IU/g (5 mg/kg - calculated in pure nisin) to help reduce the pasteurization temperature&amp;nbsp;to 80&amp;deg;C for 15 minutes. The final product has the same effectively pasteurized as the sample&amp;nbsp;without the addition of nisin pasteurized at 95&amp;deg;C/15 minutes with parameters such as color&amp;nbsp;(L, a, b are 8.15 &amp;plusmn; 0.37, 11.17 &amp;plusmn; 0.49 and 8.63 &amp;plusmn; 0.37), the vitamin C content is retained at&amp;nbsp;nearly 70%, the structure is consistent without separation, and the sensory evaluation is much&amp;nbsp;higher than the pasteurized sample without adding nisin. This helps provide consumers with&amp;nbsp;a chili sauce product that not only ensures food safety and hygiene but also has good&amp;nbsp;nutritional and sensory quality.

Evaluation of the Physicochemical and Microbiological quality of Strawberry pulp in a Moroccan Food Industry Company

The present work was undertaken within a Moroccan agri-food production company to evaluate and monitor the physicochemical (pH, Brix degrees, etc.) and microbiological parameters of strawberry pulp destined for export and other companies. After pasteurization, these analyses were carried out on the raw material and the strawberry pulp. The results showed that the physicochemical and microbiological parameters studied met standards, with a total absence of pathogenic microorganisms. The ultimate aim of the present study is to find pasteurization conditions that are effective against all pathogens while maintaining the organoleptic quality of the finished product. Moreover, consequently, to reduce energy losses within this company. To this end, we have shown that the effective pasteurization temperature is 85°C/7.5 min or 89°C/4.6min.

Stability of color and biologically active compounds of pasteurized juices from potatoes with colored flesh.

Juices from potato varieties with colored flesh contain a large amount of biologically active compounds, but they tend to darken enzymatically, which deteriorates the quality. One of the factors that can improve the color of juices is pasteurization. The aim of the study was to investigate the effect of pasteurization temperature on the anthocyanin content and color of juices from potatoes with colored flesh. The research material included juices from potato varieties with red and purple flesh. Juices pasteurized at 75 °C were characterized by the lightest color and an increase in the a* (red color) and b* (yellow color) parameters compared to unpasteurized juices. Pasteurization of juices reduced the amount of glycoalkaloids by an average of 54% compared to unpasteurized juices (larger losses in the content of α-chaconine than α-solanine). Purple potato juices showed a higher content of total polyphenols by an average of 30% and anthocyanins by 70% than juices from red potatoes. Pelargonidin and its derivatives were identified in red potato juices, while petunidin and peonidin were the most abundant in purple potato juices. Higher losses of total polyphenols were found in juices from red varieties of potatoes, while anthocyanins were less thermostable in juices from varieties with purple flesh.

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.

Characterization of Pseudomonas spp. contamination and in situ spoilage potential in pasteurized milk production process

To investigate the prevalence of Pseudomonas in the pasteurized milk production process and its effect on milk quality, 106 strains of Pseudomonas were isolated from the pasteurized milk production process of a milk production plant in Shaanxi Province, China. The protease, lipase and biofilm-producing capacities of the 106 Pseudomonas strains were evaluated, and the spoilage enzyme activities of their metabolites were assessed by simulating temperature incubation in the refrigerated (7 °C) and transport environment (25 °C) segments and thermal treatments of pasteurization (75 °C, 5 min) and ultra-high temperature sterilization (121 °C, 15 s). A phylogenetic tree was drawn based on 16S rDNA gene sequencing and the top 5 strains were selected as representative strains to identify their in situ spoilage potential by examining their growth potential and ability to hydrolyze proteins and lipids in milk using growth curves, pH, whiteness, Zeta-potential, lipid oxidation, SDS-PAGE and volatile flavor compounds. The results showed that half and more of the isolated Pseudomonas had spoilage enzyme production and biofilm capacity, and the spoilage enzyme activity of metabolites was affected by the culture temperature and sterilization method, but ultra-high temperature sterilization could not completely eliminate the enzyme activity. The growth of Pseudomonas lundensis and Pseudomonas qingdaonensis was less affected by temperature and time, and the hydrolytic capacity of extracellular protease and lipase secreted by Pseudomonas lurida was the strongest, which had the greatest effect on milk quality. Therefore, it is crucial to identify the key contamination links of Pseudomonas, the main bacteria responsible for milk spoilage, and the influence of environmental factors on its deterioration.

Investigating Milk Fat Globule Structure, Size, and Functionality after Thermal Processing and Homogenization of Human Milk.

Human milk provides bioactive compounds such as milk fat globules (MFGs), which promote brain development, modulate the immune system, and hold antimicrobial properties. To ensure microbiological safety, donor milk banks apply heat treatments. This study compares the effects of heat treatments and homogenization on MFG's physicochemical properties, bioactivity, and bioavailability. Vat pasteurization (Vat-PT), retort (RTR), and ultra-high temperature (UHT) were performed with or without homogenization. UHT, RTR, and homogenization increased the colloidal dispersion of globules, as indicated by increased zeta potential. The RTR treatment completely inactivated xanthine oxidase activity (a marker of MFG bioactivity), whereas UHT reduced its activity by 93%. Interestingly, Vat-PT resulted in less damage, with 28% activity retention. Sialic acid, an important compound for brain health, was unaffected by processing. Importantly, homogenization increased the in vitro lipolysis of MFG, suggesting that this treatment could increase the digestibility of MFG. In terms of color, homogenization led to higher L* values, indicating increased whiteness due to finer dispersion of the fat and casein micelles (and thus greater light scattering), whereas UHT and RTR increased b* values associated with Maillard reactions. This study highlights the nuanced effects of processing conditions on MFG properties, emphasizing the retention of native characteristics in Vat-PT-treated human milk.

Evaluation of the thermal degradation kinetics of vitamin C in the pulp of tumbo (Passiflora mollissima b.)

Vitamin C is an important micronutrient, which is found in acidic fruits such is the case of tumbo, studies have shown beneficial effects of vitamin C on health due to its antioxidant and free radical scavenging capabilities. The objective of the research was to evaluate the thermal degradation kinetics of vitamin C of the pulp of tumbo (Passiflora mollissima b.). The pulp of tumbo was prepared and subsequently subjected to different temperatures (60, 70 and 80 ° C) and times (0, 5, 10, 15 and 20 min). The vitamin C content in the pulp of tumbo was 77.01 mg / 100g which was analyzed by spectrophotometry. The results showed that vitamin Cdegradation followed second-order kinetic models. The degradation rate constants for ascorbic acid in the tumbo pulp were: k60 = 0.014 min-1, k70 = 0.019 min-1 and k80 = 0.023 min-1 and the decimal reduction times are: D60 = 162.17 min, D70 = 121.74 min and D80 = 101.76 min. The z value was 99 ° C, the Ea in the temperature range of 60-80 ° C is 22.84 kJ / mol and the value of Q10 is 1.60. The optimal time and temperature of pasteurization in the pulp of tumbo is 10.69 min at 60 ° C, for presenting the best correlation index, retaining the greatest amount of ascorbic acid, presenting a lower reaction rate and requiring a longer time of decimal reduction. It was concluded that the higher the temperature, the higher the degradation of vitamin C, the data obtained will help to predict the best conditions of processing of the pulp of tumbo and minimize degradation since it is an important quality factor.

Investigation of parameters causing can bulging during pasteurization process of carbonated beverage

In-package pasteurization was typically used to achieve microbial and quality stabilization in the beer industry. However, the process can cause can bulging, resulting in product loss. This work aimed to construct a mathematical model describing correlations between can thickness, fill volume, and pasteurization temperature and their effects on internal pressure of canned beer. Selected ranges of these parameters for the study were 0.245-0.270 mm, 320-338 mL and 59-66oC, respectively. Canned beer samples were pasteurized using laboratory-scale pasteurization set up for two hrs before being measured for their internal pressures. A mathematical model (R2 = 0.90) was obtained and validated. It showed that all independent parameters significantly affected internal pressure (p&lt;0.05). This model can serve as a guideline for packaging and heating process optimization to reduce the possibility of can bulging from buildup of internal pressure.

Assessing passive thermosyphon solar water heater as low-cost, sustainable water disinfection technology: Leveraging the Germicidal effect of copper and thermal convection loops

This study investigated the passive thermosyphon solar water heater (TSWH) as a domestic size point-of-use water disinfection treatment system for inactivating bacteria by utilizing both the germicidal properties of copper in heat exchanger and the heat generated in thermal convection loops. Additionally, life cycle analysis and manufacturing cost analysis were conducted to reveal its environmental and economic benefits. Initially, the germicidal capacity of copper tube against E. coli and total coliform in rapidly flowing polluted water was tested in laboratory settings with contact times ranging from 1.5 to 94 min. Without any additional heat, the copper tubes achieved 99.9% (log 3.01) removal of E. coli, and 99.24% (log 2.12) removal of total coliform after 94 min of contact. In the presence of heat (50–80 ºC), complete removal of the bacteria was achieved after only 1.5 mins of contact time at 50ºC. A domestic-sized passive TSWH with a copper tube heat exchanger was evaluated for disinfecting 20 L/day of microbiologically polluted tap water and synthetic groundwater in a field study. The average contact time of polluted water in copper tube heat exchanger was 5.58±1.2 min in the morning (with an outlet water temperature of 87.3 ºC), and 11.83±1.41 min in the afternoon (with an outlet water temperature of 78±5.1 ºC). These contact times and temperatures, achieved throughout the year, were sufficient to meet the required minimum for complete bacterial removal in the synthetic groundwater. Importantly, the system achieved complete inactivation of pathogens at pasteurization temperatures below 75 ºC, relying solely on the combined effect of copper and thermal convection loops, without pumps or electricity. Compared to an active TSWH using circulating pumps and controls, the passive system generated 62.2% less green house gas, had 55.5% lower cumulative energy demand and cost 323.3 $ compared to 544.64 $. Highlighting significant economic and environmental benefits, the passive TSWH offers a promising solution for disinfecting water in low-income areas with limited access to safe water.

The impact of heat treatment of bovine milk on gastric emptying and nutrient appearance in peripheral circulation in healthy females: a randomized controlled trial comparing pasteurized and ultra-high temperature milk

BackgroundHeat treatments of dairy, including pasteurization and ultra-high temperature (UHT) processing, alter milk macromolecular structures, and ultimately affect digestion. In vitro, animal, and human studies show faster nutrient release or circulating appearance after consuming UHT milk (UHT-M) compared with pasteurized milk (PAST-M), with a faster gastric emptying (GE) rate proposed as a possible mechanism. ObjectivesTo investigate the impact of milk heat treatment on GE as a mechanism of faster nutrient appearance in blood. We hypothesized that GE and circulating nutrient delivery following consumption would be faster for UHT-M than PAST-M. MethodsIn this double-blind randomized controlled cross-over trial, healthy female (n = 20; 27.3 ± 1.4 y, mean ± SD) habitual dairy consumers, consumed 500 mL of either homogenized bovine UHT-M or PAST-M (1340 compared with 1320 kJ). Gastric content volume (GCV) emptying half-time (T50) was assessed over 3 h by magnetic resonance imaging subjective digestive symptoms, plasma amino acid, lipid and B vitamin concentrations, and gastric myoelectrical activity were measured over 5 h. ResultsAlthough GCV T50 did not differ (102 ± 7 min compared with 89 ± 8 min, mean ± SEM, UHT-M and PAST-M, respectively; P = 0.051), GCV time to emptying 25% of the volume was 31% longer following UHT-M compared with PAST-M (42 ± 2 compared with 32 ± 4 min, P = 0.004). Although GCV remained larger for a longer duration following UHT-M (treatment × time interaction, P = 0.002), plasma essential amino acid AUC was greater following UHT-M than PAST-M (55,324 ± 3809 compared with 36,598 ± 5673 μmol·min·L-1, P = 0.006). Heat treatment did not impact gastric myoelectrical activity, plasma appetite hormone markers or subjective appetite scores. ConclusionsContrary to expectations, GE was slower with UHT-M, yet, as anticipated, aminoacidemia was greater. The larger GCV following UHT-M suggests that gastric volume may poorly predict circulating nutrient appearance from complex food matrices. Dairy heat treatment may be an effective tool to modify nutrient release by impacting digestion kinetics. Clinical Trial Registrywww.anzctr.org.au (ACTRN12620000172909).

Effect of pasteurization time and temperature on bioactive compounds, antioxidant ability and color value of beverage produced from herbal extract (Passiflora foetida and embryo nelumbinis)

Herbal beverage is one of the natural products which are greatly preferred by customers. Passiflora foetida and Embryo Nelumbinis are two kinds of medicinal plants that possess many precious bioactive compounds that have the effect of supporting calmness, reducing stress, treating insomnia; and have been used in many folk remedies in Vietnam. The main objective of this study is to investigate the effects of heating temperature (75, 85 and 95°C) and pasteurization time (15, 30, 45 and 60 minutes) on the content of bioactive compounds (polyphenol, flavonoid, tannin, alkaloid and saponin), antioxidant ability (FRAP, DPPH) and color parameters (L*, a*, b* and ΔE) of product. The reseach was designed randomly with two factors and three replications. The content of bioactive compounds and antioxidant capacity of product were analyzed by standardization methods using spectrophotometer; and the color parameters were measured by the colorimeter. The result showed that the opitmal pasteurization temperature and time were 85°C and 30 minutes, at this heating process the product maintained high level of bioactive compounds and antioxidant ability. The content of polyphenol, flavonoid, tannin, saponin and alkaloid were 9.46 mgGAE/g, 4.44 mgQE/g, 4.85 mgTAE/g, 7.40 mgSE/g, 14.25 mgCE/g; the antioxidant capacity of product by DPPH and FRAP method were 64.50% and 28.25 μFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as LMFeSO4/g; the color parameters such as L*, a*, b* and ΔE were 31.58, -0.24, -0.47 and 61.25, respectively. The production process was successful in pilot equipment and the product can be used as one of the beverages for health strengthening.

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.