Decrease in the Antioxidant Capacity in Beverages Containing Tea Extracts during Storage

Enriching alginate matrix used for probiotic encapsulation with whey protein concentrate or its trypsin-derived hydrolysate: Impact on antioxidant capacity and stability of fermented whey-based beverages

Este trabalho teve como objetivo a elaboração de uma bebida eletrolítica a base de permeado da ultrafiltração de leite e avaliação de suas características físicas, químicas e microbiológicas, durante o período de armazenamento por 30 dias, nas temperaturas de 7°C e 25°C. A bebida apresentou-se clara, com coloração amarelo-esverdeada, osmolalidade de 311,6mOsmol.L-1 e carboidratos totais de 6,48% m/v. Não foram observadas alterações significativas de pH, acidez titulável e sólidos solúveis durante o tempo e temperatura de armazenamento (P>0,05). A osmolalidade e o teor de açúcares totais foram afetados pelo tempo (P<0,05), enquanto que o aumento de açúcares redutores foi afetado pelo tempo e pela temperatura de armazenamento (P<0,05). Observou-se correlação positiva (P<0,05) entre o teor de açúcares redutores e totais com a osmolalidade,porém a bebida manteve-se dentro da faixa de osmolalidade(entre 290mOsm L-1 e 330mOsm L-1). As coordenadas L*, a*, b* e C* foram afetadas somente pelo tempo de armazenamento (P<0,05). No estudo de vida útil, a bebida mostrou-se estável microbiologicamente. Assim, o permeado pode ser aproveitado como coproduto industrial na elaboração de bebidas eletrolíticas, em vista dos critérios de osmolalidade, além de conter minerais naturais

This study aimed to trap green tea extract (GTE) with maltodextrin (MD) to protect catechins from high temperatures, pH variations, and storage. GTE:MD microparticles (19.35:80.65% wt/wt) were obtained by spray drying, producing microparticles (26 μm) with a trapping efficiency of 63%, containing epigallocatechin gallate (EGCG), gallocatechin gallate, epigallocatechin (EGC), epicatechin, and catechin. The free GTE evaporated at 43℃, loosed 50% of its weight at 100℃, and decomposed at 130℃. The microparticles started to weight loss at 75℃ and decomposed at 290℃. The EGCG and EGC content of the free GTE completely depleted after 30 days at pH 7 and pH 6, respectively. However, the microparticles increased their EGCG content to 121% after 30 days at pH 7 and reduced 3.5% the EGC content after 30 days at pH 6. MD was an effective barrier capable of stabilizing the GTE’s polyphenolic content and antioxidant capacity. Practical applications The bioactive compounds of the green tea extracts (GTEs) are catechins with antioxidant activity; however, these compounds and their activity may decrease with the epimerization caused by high temperatures, pH variations, and storage. The immobilization of GTE in maltodextrin (MD) preserved its polyphenols’ chemical structures and their antioxidant capacity at different pH and storage times; in addition, the MD immobilization offered thermal protection to the GTE. The results of our study allow us to advance the knowledge in the field, understanding the interactions between GTE components and MD molecules and the possibility of a commercial application of our study.

The primary aim of this research endeavor is to develop an innovative herbal beverage that integrates extracts derived from both the cruciferous (CR) and pumpkin (PU) botanical families. The phytochemical constituents of the chosen plants were meticulously characterized employing Gas Chromatography-Mass Spectrometry (GC–MS) techniques. The PU extract demonstrated the most elevated concentrations of ascorbic acid (98.66 ± 13.29) and total phenolic content (TPC) (1.66 ± 0.004), whereas the white cabbage (CA) extract exhibited the highest total flavonoid content (TFC) (0.42 ± 0.004). An augmentation in the concentration of the extracts was concomitant with a marked enhancement in the antioxidant capacity (For example, from 10 to 65% for CA with an increase in concentration from 50 to 800 µg/mL). The physicochemical analysis of the beverages revealed statistically significant disparities among the samples with respect to the assessed parameters (p < 0.05). In the evaluation of antioxidant activity, TPC and ascorbic acid levels of the beverages were modulated by both the concentration of the extract and the duration of storage (For example, a 10–12% decrease in antioxidant capacity, a 60–80% decrease in TPC, and a 10–24% decrease in vitamin C were observed after 90 days of storage), resulting in fluctuations in these parameters, respectively. The findings from the sensory evaluation indicated that the two apple-kiwi beverages (from 8 to 9.7) were received with a greater degree of acceptability in comparison to the two base beverages (from 2 to 8). With regard to physical–chemical properties and sensory evaluation, the two apple-kiwi beverages were adjudged more favorable than the base beverage. Conversely, in the examination of the Vitamin C content, TPC, and antioxidant activity of the beverages, it was noted that an increase in extract concentration correspondingly elevated these parameters within the beverages.

The effect of ascorbic acid on total antioxidant activity of black and green teas

The effects of product and preparation variables on the in-cup chemical composition of tea extracts is of interest because the appearance and taste characteristics and the possible health effects of a tea liquor arise from the chemical components extracted from the leaf during tea preparation. A comprehensive study was therefore undertaken to determine the contributions of product and preparation variables on the total soluble solids, caffeine, and polyphenol contents of tea extracts. The results of this study show that the variety, growing environment, manufacturing conditions, and grade (particle size) of the tea leaves each influence the tea leaf and final infusion compositions. In addition, the composition of the tea infusion was shown to be influenced by whether the tea was contained in a teabag and, if so, the size and material of construction of the bag. Finally, the preparation method, including the amounts of tea and water used, infusion time, and amount of agitation, was shown to be a major determinant of the component concentrations of tea beverages as consumed. An illustration of the variation introduced by these product and preparation factors is provided by comparing solids, caffeine, and polyphenol contents of green and black tea infusions when commercial products are prepared according to the instructions given on their packaging.

During postharvest storage oca tubers can pass for different stages, in which bioactive compounds can change their content; and specifically the sprouting stage, can alter significatively these components. Therefore, this study evaluated the sprout length, loss weight, reducing sugar content, total phenolics content, and antioxidant capacity of three oca tuber varieties (yellow, purple, and orange) during postharvest storage. Oca tuber varieties were stored at 19 °C ±1 ºC and relative humidity of 85% ±1%. A factorial design was used to evaluate the effect of oca variety and postharvest storage time (0, 15, 30, 45, 60, 75, and 90 days). The sprout length of the three oca varieties begin to growth at 15-30 days of postharvest storage, which indicated that dormancy period was broken, moreover, the sprout length was increased until 90 days of storage. Yellow oca had the longest sprout length (26.4 cm) and the highest loss weight (22.55 %) at 90 days of storage, which indicated an effect of oca variety and postharvest storage time (p value≤0.05). The reducing sugar content, total phenolics content, and antioxidant capacity of the three oca varieties exhibited variable behaviors during storage time and initially oca tubers showed a reduction in their values, which were presumably related to the stabilization period. The postharvest storage time and oca variety produced different physiological changes in the oca tubers, which affect the sprout length, weight loss, reducing sugars, total phenolics content, and antioxidant capacity.

SummaryThe aim of this work was to evaluate the effect of nitrate reduction and storage time on the content of amino acids and biogenic amines (BAs), total antioxidant capacity (TAC) and antioxidative properties of peptides isolated from dry fermented loins. The results showed that reducing the addition of nitrates increased the amount of BAs formed during storage of dry fermented loins. The lowest TAC value (tested by ABTS assay) was recorded for the sample with the highest nitrate addition (150 mg kg‐1) at beginning, while the highest value was noted for the sample without nitrate addition at 180 days of storage. The amino acid profile showed that dry fermented loin with the highest addition of nitrate was characterised by a significantly lower content of amino acids, which are precursors of key aroma compounds compared with loin samples with a lower amount of added sodium nitrate. The sum of ranking differences (SRD) indicated that loin sample with traditional addition of nitrate (150 mg kg‐1) after 120 days of storage was characterised by the lowest SRD result, which means that they are the closest to the assumed values, that is the lowest content of BAs, the highest antioxidant activity and amino acid patterns recommended by WHO/FAO/UNU Experts.

White tea alleviates non-alcoholic fatty liver disease by regulating energy expenditure and lipid metabolism

Green tea extract as a natural antioxidant to extend the shelf-life of fresh-cut lettuce

The objectives of the present study were to determine the effects of the brewing method on the amount of the major catechins, methylxanthines, total polyphenols and antioxidant capacity in green and black teas, and to correlate the chemical composition of tea infusions to their sensorial properties by the combined use of the electronic nose and tongue. For this purpose, tea infusions were prepared from 7 green teas and 6 black teas using different extraction times (3 - 5 and 10 min). The extraction of total polyphenols and catechins was increased by prolonging the infusion time from 3 - 5 to 10 min, while the caffeine amounts did not increase. The antioxidant activity of teas was well correlated with polyphenol content. Electronic tongue and electronic nose were able to discriminate green teas from black teas on the basis of their sensorial properties. Considering the taste, green teas were characterized by astringency and aftertaste-astringency and this sensation was increased by prolonging the infusion time; black teas were perceived as more bitter, sour, salty and the extraction time affected the astringent sensation. The aroma of green and black teas was discriminated by specific sensors and the increase of the extraction time produced more richly flavoured infusions. This work adds information about correlation between sensorial properties, antioxidant capacity and chemical composition of green and black teas.

Intestinal and colonic bioaccessibility of phenolic compounds from fruit smoothies as affected by the thermal processing and the storage conditions

This study aimed to evaluate the effects of the separate provision of green and oregano tea extracts on the biomarkers of the redox state and health condition in pre-weaned Jersey calves from birth to 60 days of life. Two experiments following the complete randomized design with measures repeated in time were carried out using 38 Jersey calves (17 and 21 calves in experiments 1 and 2, respectively). Calves were distributed according to date of birth into one of three groups: control (CON) - with no addition of extracts; oregano extract (OE) - addition of 70 mg of oregano extract/kg of body weight (BW) and green tea extract (GT) - addition of 35 mg of green tea extract/kg of BW. Eight biomarkers of the redox state were evaluated on days 1, 30, and 60 after birth, and variables measured on day 1 were used as covariates. Body temperature and occurrence of diarrhea were evaluated every two days. Regarding the main results, the supply of oregano extract reduced the concentration of oxidizing biomarkers, such as DCFP (oxidation of dichlorofluorescein in plasma) and carbonyl, and increased the activity of antioxidant enzymes, such as GPx and catalase. Green tea extract only reduced DCFP and tended to improve catalase activity. Calves remained healthy (no fever and only a few days with diarrhea), and plant extracts did not improve their health condition. The addition of green tea and oregano extracts into the diet has a positive effect on redox status in pre-weaned Jersey calves.

To maximize the initial quality going to storage and maintain the postharvest antioxidant property of the minimally processed corn salad, the synergistic effects of culture systems (traditional soil culture system [TCS] vs. soilless culture system [SCS]), washing practices (unwashed vs. washed), packaging methods (flow pack bag [FPB] vs. flow pack tray [FPT]), and storage temperatures (4°C vs. 8°C) on the antioxidant property of minimally processed corn salad (Valerianella olitoria L.) was investigated during 7 days of storage. The results showed that SCS-grown corn salad contained significantly higher levels of total ascorbic acid (TAA) (25.6%), ascorbic acid (AA) (17.5%), total phenols (TP) (57.0%), and antioxidant capacity (AC) (67.0%), but lower levels of chlorophyll and carotenoid than TCS. TAA, AA, and TP were the main contributors to AC, with highly positive correlations between them. Washing practice induced a transient increase in AC value only on processing day (d0). The AC value was significantly higher in SCS-grown leaves than in TCS-grown leaves during the storage period. FPT packaging had a considerable impact on pigments preservation and DHA generation, which was highly culture system-depended. The storage temperature showed no significant influence on overall quality. Browning enzyme (phenylalanine ammonia-lyase [PAL], polyphenol oxidase [PPO], peroxidase [POD]) activities were significantly influenced by factors tested and changed over time. However, no visible browning spots were observed at the end of storage. After 7 days of storage, all leaves were still fresh and marketable with the largest fresh weight loss of 0.38%. Conclusively, the synergism of SCS, washing practice, and FPT favored obtaining high-quality raw material at harvest and maintaining the postharvest antioxidant property of minimally processed corn salad during storage. This unique finding not only offers an innovative and feasible strategy for the fresh-cut industry to produce higher-quality products that meet the growing expectations and demands of modern consumers, but also emphasizes the significance of integrating preharvest and postharvest factors within the fresh supply chain.

This experiment was conducted to determine the optimum level of green tea extract (GTE) in diets without antibiotics and to evaluate its effect on broiler performances. A total of 100 Cob broiler chicks were kept for a period of 5 weeks. Dietary treatments used in this experiment were antibiotic free group (basal diet as a control), GTE 0.5% (basal + GTE 0.5%), GTE 1% (basal + GTE 1%) and GTE 2% (basal + GTE 2%) and antibiotic added group (basal + 0.05% oxytetracycline). GTE supplemented group showed significantly higher body weight and better feed conversion ratio (FCR) than other treatments (P &lt; 0.05) where highest live weight (2034 g/bird) was recorded in broilers group provided with 0.5% GTE. The best FCR (1.58) was observed in the group supplemented with 0.5% GTE. The obtained results also revealed significant (P &lt; 0.05) difference among treatments in the lipid profile parameters (total cholesterol, HDL and triglyceride except LDL). Broilers treated with 0.5% GTE showed lowest total cholesterol (115.0 mg/dl), triglyceride (116.3 mg/dl) and highest HDL (30.75 mg/dl). In conclusion, GTE can be added in the diet @ 0.5% for better growth performances of broiler as an alternative to antibiotic without any negative effect on lipid profile.&#x0D; Res. Agric., Livest. Fish.8(1): 157-163, April 2021