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Subject: search.filters.subject.Phenolic acids

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    Changes in ascorbic acid, total polyphenol, phenolic acids and antioxidant activity in juice extracted from coated kiew wan tangerine during storage at 4, 12 and 20°c
    (2010-03-01)
    Puttongsiri, Tongchai
    ;
    Haruenkit, Ratiporn
    The aim of this research was to investigate changes in ascorbic acid, total polyphenol, phenolic acids and antioxidant activity in juice extracted from Kiew Wan tangerines (Citrus reticulate Blanco cv. Kiew Wan) coated with shellac. The coated fruits were stored for five weeks at 4, 12 and 20°C and samples were taken weekly for analysis. Ascorbic acid decreased during storage at all tested temperatures. The major phenolic acids found were ferulic acid followed by sinapic, caffeic and p-coumaric acid. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2 azinobis (3-ethylbenzothiazoline-6-sulfonate (ABTS) antioxidant activities increased during storage and were correlated with total polyphenol and phenolic acid contents. Sinapic, caffeic and p-coumaric acid levels were significantly correlated with the DPPH while ferulic acid was correlated with the ABTS. All phenolic acids increased during the early stage of storage at 4 and 12°C but decreased at the end. Weight loss of coated fruit during storage was in the range of 4-17%.
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    Comparison of the contents of the main antioxidant compounds and the antioxidant activity of white grapefruit and his new hybrid
    (2004-01-01)
    Gorinstein, Shela
    ;
    Zachwieja, Zofia
    ;
    Katrich, Elena
    ;
    Pawelzik, Elke
    ;
    Haruenkit, Ratiporn
    The aim of this study was to compare the main antioxidant compounds content and the antioxidant activity of white grapefruit and his new hybrid (Jaffa Sweeties). Total phenols were measured colorimetrically using the Folin-Ciocalteu reagent, phenolic acids - by HPLC, anthocyanins and flavonoids - spectrophotometrically. The antioxidant activity of these fruits was determined by total antioxidant activity (TAA) and nitric oxide (NO) methods. Trans-hydroxycinnamic acids (caffeic, p-coumaric, ferulic, and sinapic) were more abundant in white grapefruit than in his hybrid. However, on a fresh weight basis, grapefruit's hybrid has a higher total phenol content as well as a higher antioxidant capacity in comparison with white grapefruit. A linear relationship existed between TAA and anthocyanins (R<sup>2</sup> = 0.8068), TAA and flavonoids (R<sup>2</sup> = 0.9320) and TAA and total phenols (R <sup>2</sup> = 0.9446). Our findings indicate the following: (1) Both studied fruits contain a high concentration of natural antioxidants that have not only a high antioxidant activity, but also a good antioxidant quality. (2) The total phenol content and the antioxidant potential are significantly higher in the grapefruit hybrids than in white grapefruits. © 2003 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved.
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    Comparison of some biochemical characteristics of different citrus fruits
    (2001-08-29)
    Gorinstein, Shela
    ;
    Martín-Belloso, Olga
    ;
    Park, Yong Seo
    ;
    Haruenkit, Ratiporn
    ;
    Lojek, Antonin
    The goal of this investigation was to evaluate the antioxidant properties of some citrus fruits. The contents of dietary fibre, total polyphenols, essential phenolics, ascorbic acid and some trace elements of lemons, oranges and grapefruits were determined and compared with their total radical-trapping antioxidative potential (TRAP). There were no significant differences in the contents of total, soluble and insoluble dietary fibre in the studied peeled fruits or their peels. The contents of total, soluble and insoluble dietary fibre in peels were significantly higher than in peeled fruits (P < 0.05 in all cases). The peeled lemons, oranges and grapefruits contain 164±10.3; 154±10.2 and 135±10.1 and their peels 190±10.6; 179±10.5 and 155±10.3 mg/100 g of total polyphenols, respectively. The content of total polyphenols in peeled lemons and their peels was significantly higher than in peeled oranges and grapefruits and their peels, respectively. The content of total polyphenols in the peels was significantly higher than in peeled fruits (P < 0.05 in all cases). The same results were obtained in the investigation of essential phenolics and ascorbic acid. The content of Fe in peeled lemons and their peels was significantly higher than in peeled oranges and grapefruits and their peels, respectively. Also the TRAP was significantly higher in peeled lemons and their peels than in peeled oranges and grapefruits and their peels, respectively. In all three fruits, the TRAP was significantly higher in peels than in peeled fruits (P < 0.05). In conclusion, lemons possess the highest antioxidant potential among the studied citrus fruits and are preferable for dietary prevention of cardiovascular and other diseases. The peels of all citrus fruits are rich in dietary fibres and phenolic compounds and suitable for industrial processing. © 2001 Elsevier Science Ltd. All rights reserved.