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The presence of many different antioxidant species makes fruit juices to be perceived by populations as a very healthy beverage easy to include in the daily diet. These antioxidant actions have been reported in a large number of papers, however the information correlating the antioxidant profile with the physicochemical characteristics derived from the industrial processing of fruit juices is limited. In a previous paper, our research group demonstrated that the antioxidant properties of citrus juices were underestimated when measuring by traditional methods and that our improved methodology, so-called GAR, is a better approach to analyze the global antioxidant response of juices. In this paper, we confirm that statement, establishing that the overall antioxidant capacity of non-citrus juices is 10-times higher with the GAR method (including an in vitro gastrointestinal digestion) that with the other methodologies. In some cases, such as pineapple juice, the antioxidant action was distributed between the soluble and non-soluble fractions almost at 50%. But, surprisingly, in some other (like tomato juice) the non-soluble fraction accounted for the higher antioxidant capacity. This fact definitively underlines the importance of the non-soluble fraction and shows the suitability of the GAR method to consider it. Physicochemical parameters, such as color, fluorescence, 5-hydroxymethylfurfural and furfural contents were correlated with antioxidant characteristics in some samples. Lastly, we unravel a mathematical model to classify non-citrus juices depending on their nature or storage conditions. [ABSTRACT FROM AUTHOR]

Citrus juices are perceived as healthy foods by consumers due to their richness in antioxidant compounds. Despite the large number of papers about the antioxidant activity of citrus juices, less is known about the relationship with physicochemical properties. This paper shows that the overall antioxidant activity of citrus juices is underestimated with the standard methodologies, being up to 10-times higher with the GAR method (including an in vitro gastrointestinal digestion). 70% of the antioxidant activity was found in the soluble fraction and citrus juices contributed up to 12% of the overall antioxidant intake within the Spanish diet. Physicochemical parameters, such as colour, fluorescence, 5-hydroxymethylfurfural and furfural contents, were correlated with nutritional parameters in some samples. The intake of HMF was negligible from commercial citrus juices and was absent in freshly squeezed ones. Finally, a mathematical model is developed to classify juices depending on their nature or storage conditions. [ABSTRACT FROM AUTHOR]

Abstract: Several methods have been applied to measure antioxidants in foods. Extraction methods have previously relied on chemical methods which are non-physiological or based on enzymatic hydrolysis. Whatever the method used, the insoluble fraction is systematically excluded. The global antioxidant response (GAR) method use an in vitro approach with enzymatic digestion, designed to mimic digestion through the gastrointestinal tract, aimed to release antioxidants from foods. A total of 27 samples were analysed using the ABTS and FRAP assays applied to the soluble and insoluble fractions. The GAR method showed a higher antioxidant activity compared with the usual chemical extraction and the Quencher (direct) method. The soluble fraction was more antioxidant than the chemical extracts due to the release of compounds from the hydrolysis of carbohydrates and proteins. In addition, the GAR method allowed the measurement of the antioxidant activity in the insoluble fraction, which was important in fibre-rich samples. [Copyright &y& Elsevier]

• Neither anthropometric measurements nor plasmatic lipids changed after salami intake. • Salami enriched with dietary fiber led to higher abundances of butyrate producing gut microbes. • Salami enriched with dietary fiber improves butyric acid production by gut microbiota. • Inflammatory markers, TNF-α and CRP decreased while plasmatic antioxidant capacity increased. A human intervention in 24 healthy volunteers was performed to test the potential health benefits of a fermented salami with a probiotic Lactobacillus rhamnosus HN001 and added citrus fiber. Anthropometric measurements and blood biochemistry did not show any significant differences between pre- and post-intervention during 4 weeks with a daily intake of 30 g of salami, neither with regular salami (control group) nor with reformulated salami (intervention group). However, the inflammatory markers CRP and TNFα decreased significantly after intervention, suggesting a less inflammatory environment after reformulated salami consumption. Antioxidant plasmatic markers also improved within the intervention group. Butyrate production was significantly increased after reformulated salami consumption. Gut microbiota community structure, however, was not significantly shaped by neither regular nor reformulated salami. After the intervention with probiotic salami, L. rhamnosus was detected by quantitative polymerase chain reaction (qPCR) in all samples of the intervention group but not in the control group, showing probiotic effect. [ABSTRACT FROM AUTHOR]

Many methods have been developed to measure the antioxidant capacity of foods under non physiological-relevant conditions. In this study, three methods (TEAC OH , GEAC RED and TEAC AAPH ) are developed to measure antioxidant capacity at physiological pH, using indigo carmine as a redox dye. TEAC OH and TEAC AAPH determine foodstuffs’ scavenging capacity against hydroxyl (OH ) and AAPH radicals, while the third method measures the global reducing capacity of the sample. The results obtained for commercial teas, commercial beverages containing tea as the main ingredient and different solid foods (spinach, onion, salami, etc.) were compared with well-established protocols. The new methods demonstrated good linearity-reproducibility, providing reliable data about the antioxidant capacity of foods under physiological-resembling conditions. The new methods were also useful for evaluating the antioxidant capacity of human plasma after acute intake of tea. The physiological-resembling conditions of these assays and the use of absorbance readings make them suitable for application by any laboratory. [ABSTRACT FROM AUTHOR]

The antioxidant capacity of food influences its shelf life and human health. To determine this parameter, the corresponding antioxidant species must first be extracted. Current methods don’t adequately address this issue since they rely on extractions with organic solvents or on in vitro digestion without a subsequent fermentation. We present an improved protocol to determine the global antioxidant response of foods (GAR+) including both in vitro digestion and fermentation. All samples should be fermented with the same fresh faecal inoculum in order to decrease variability. In addition, the use of a pool of faeces from healthy donors is strongly recommended to improve repeatability. Although most antioxidant capacity is achieved after digestion, in some foods fermentation plays a role. Thus, the GAR+ method provides reliable values of the antioxidant capacity of foods that are closer to their in vivo activity by including the effects of gut microbiota over non-digested nutrients. [ABSTRACT FROM AUTHOR]

Abstract One of the most consumed beverages around the world is tea, but little is known about how tea quality can be monitored during storage and processing. Thus, the objective of this research was to study the usefulness of furosine and 5-hydroxymethylfurfural (HMF) content -two Maillard reaction markers-as quantitative parameters that control tea processing and storage. Two different experiments were carried out: one using green and black teas (processed at laboratory scale) and another one using commercial green, white, black and red teas that were under storage for one year (shelf life) and under accelerated conditions (55 °C at 40% of humidity for 3 months). The samples were analyzed for the content of furosine, HMF, and free and total lysine. The combination of HMF and furosine was useful as an indicator to control tea processing and storage regardless the type of tea. HMF and furosine are useful chemical indicators (when combined) to monitor tea quality during processing and storage. Furosine analysis is especially sensitive to control the first drying steps, while HMF reflects those changes occurred in the last tea processing steps. Highlights • The usefulness of furosine and HMF as quality indicators of tea was studied. • The combination of HMF-furosine was useful to control tea processing. • HMF was a good indicator of storage conditions in commercial teas. [ABSTRACT FROM AUTHOR]

White tea is highly consumed due to its sensory properties and health benefits, although most scientific reports don’t include the analysis of both properties. Therefore, the objective of the present study was to unravel the best brewing conditions for optimal extraction of the bioactive compounds and antioxidant capacity, while realising the best sensory properties. Infusions of eighty commercial teas (sold in bags or leaves) were obtained at different time–temperature ratios, studying bioactive compounds (caffeine and individual catechins), antioxidant capacity and sensory analysis. Brewing at 98 °C for 7 min was the best condition to obtain a high content of antioxidant polyphenols and pleasant sensory properties. Those teas sold in bags give rise to tea brews with almost double antioxidant capacity. In conclusion, it is very important to link sensory and chemical data to obtain optimal sensorial quality and the highest healthy properties in white tea infusions. [ABSTRACT FROM AUTHOR]

Fruits are foods that contain plenty of vitamins, minerals and some bioactive phytochemicals like polyphenols. Thus, fruits may exert different functional properties on human health, some of which are directly related to their antioxidant capacity like cancer or atherosclerosis. Owing to globalization, consumers have a wide repertory of fruits throughout the year. Among them, tropical and subtropical fruits are steadily expanding, as well as the studies about them. In this sense, this timely review focused on the nutritional value and chemical composition of persimmon and kiwifruit, two tropical fruits with a protective role on different chronic diseases. Thus, this review focused mainly on the presence of bioactive compounds such as polyphenols, tannins, carotenoids, vitamin C and the different functional properties (i.e. antioxidant capacity, antithrombotic activity, decrease of plasmatic lipids, etc.) arising from the presence of such biologically active molecules. Finally, the effects of genotype and ripening stage on antioxidant capacity and the content of bioactive compounds in persimmon and kiwifruit are also discussed. [ABSTRACT FROM AUTHOR]

• Manzanilla variety has higher PUFA and lower MUFA content than Picual. • MUFA concentration decreases and PUFA concentration increases during olive ripening. • Picual variety has higher antioxidant capacity and phenolic content than Manzanilla. • Most antioxidant capacity of olive oil is released after in vitro gut microbial fermentation. • The most affected components by variety are fatty acids whereas by harvest date are phenols. The aim of this work was to study the evolution of quality parameters, fatty acid composition, antioxidant capacity and total phenolic content of olive oil obtained from two olive varieties (Manzanilla and Picual) with different maturation. Antioxidant capacity and total phenolic content were measured after submitting the olive oil to in vitro digestion and fermentation to mimic physiological conditions. Quality parameters were always within the legal limits to be called "Extra Virgin Olive Oil". Antioxidant capacity, total phenolic content, saturated fatty acids and monounsaturated fatty acids (MUFA) decreased along maturation, whereas polyunsaturated fatty acids (PUFA) increased in both varieties. Manzanilla showed higher PUFA content, whereas Picual had higher MUFA concentration, antioxidant capacity and total phenolic content. The fermented fraction of olive oil displayed a higher antioxidant capacity. Finally, the statistical approach demonstrated that the type of variety is more important than collection date regarding fatty acid composition and antioxidant capacity. [ABSTRACT FROM AUTHOR]