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In vitro techniques are essential to assess the antioxidant potential of foods, although methods with diferent action mechanisms make troublesome data analysis. This article describes the use of artifcial neural network (ANN) to associate phenolic compounds with antioxidant activity in vitro (AOX) of grape juices. A multilayer perceptron (MLP) ANN was obtained with 28 phenolics quantifed, as input layers, and AOX measuring by DPPH, ABTS, FRAP, H2O2, and β-carotene/linoleic acid bleaching assay (βCLA) methods, as output layers. To improve discussion in food sciences, the ANN results were compared with Pearson?s correlation and principal component analysis (PCA), methods largely used in food studies. Pearson?s technique showed correlations between antioxidant methods and some of the phenolic compounds, but with limitations. PCA proved to be a more powerful method than Pearson?s correlation, as it positively associated 13 phenolics with four out of fve antioxidant methods. The MLP-ANN allowed simultaneous association of 19 individual phenolics, while a single hidden layer predicted 15 phenolics with simultaneous action in all AOX methods. The power of association was: ANN>PCA>Pearson. It was evidenced that ANN is a powerful tool for screening antioxidants in diferent AOX systems, which is applicable in health interests. Made available in DSpace on 2021-10-15T13:00:25Z (GMT). No. of bitstreams: 1 SantosLima2021-Article-ArtificialNeuralNetworkAPowerf.pdf: 1377752 bytes, checksum: e6e6d34d40c93e70d966e6c832825c70 (MD5) Previous issue date: 2021

A three-stage block freeze concentration process using minimal instrumental apparatus was studied to concentrate minerals and polyphenols in orange juice, obtaining one cryoconcentrate and one ice fraction at each stage. The process parameters were designed, and the cryoconcentrates and ice fractions were analyzed for physicochemical properties, polyphenolic composition, and mineral profile. The three-stage process obtained high concentrations of polyphenols and minerals in orange juice, with the third stage cryoconcentrate obtaining a 429% increase in polyphenols compared to the initial juice. This cryoconcentrate had the highest K, Mg, and Ca levels, while most of the minerals were significantly retained in the ice fractions. The antioxidant activity of concentrated juices increased sequentially by 168, 272, and 343% across process stages. The last two stages of cryoconcentration using only gravitational force led to high concentrations of polyphenols, minerals, soluble solids, and vitamin C in concentrated juices.

This work provides the first screening of 22 Citrus cultivars grown in a semi-arid tropical region based on their most relevant phytochemical and polyphenolic features through a multivariate approach. Multivariate chemometric analysis through PCA analysis were used combined to reach grouping of the Citrus fruits and unveil the main characteristics associated with the fruits identity and origin region. Citric acid was the dominant organic acid (4.43–140.54 g L−1), representing 93.9 % of total organic acids quantified in the samples. Glucose and fructose corresponded, respectively, to 51.2 and 48.8 % of the total sugars quantified in samples. Hesperidin was the predominant flavonoid identified in all Citrus, particularly in oranges, while in pomelos, naringin was the major polyphenol. The results showed that most phenolics are related to Citrus identity, as PCA revealed the grouping of samples according to the species or variety. The associations found for the Citrus obtained from the same semi-arid tropical location could be used as basis for authentication of these Citrus samples, as judged by the distinctions found between the phenolic profiles, sugars and organic acids. This could be used for other fruits upon verification of their polyphenolic association with location and climate.

Grape polyphenols are studied for their bioactive activities and health benefits. Grape juice clarification produces a colored non-pomace solid residue that is rich in polyphenols and may have potential for nutraceutical applications. This study therefore firstly investigated antiproliferative and anti-inflammatory properties of the non-pomace sediment of Bordo and Isabel grape juices before and after the gastrointestinal simulation, and evaluated the effects of the main individual phenolic compounds found in these sediments in regards to their antiproliferative action in healthy and cancer cells. The non-pomace sediments inhibited significantly the proliferation of colorectal adenocarcinoma cells (Caco-2) cells, whereas their digested fractions inhibited proliferation of hepatocellular carcinoma (HepG2) cells. However, the exposure to treatments caused no cell toxicity to healthy cells. When tested individually, the phenolic compounds quercetin and myricetin showed antiproliferative activity and led to cell viability of 56.47 and 51.07 % in Caco-2 cells and of 33.96 and 27.03 % in HepG2 cells, respectively. The non-pomace sediments and its digested fractions exhibited anti-inflammatory action by inhibiting the release of tumor necrosis factor alpha (TNF-α) in murine macrophages. These encouraging data suggests the potential use of this residue as dietary supplement or as a promising chemotherapy for antitumor therapies.