The antioxidant activities of the phenolic compounds found in peanut skin is well documented. The aim of the present study was to investigate the structure-activity relationship of these compounds, and more particularly, that of (＋)-catechin (monomer), procyanidin A1 (dimer), and epicatechin-(4β→6)-epicatechin-(2β→O→7,4 β→8)-catechin (EEC, trimer). Their antioxidant properties were compared using four different assays, namely, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, oxygen radical absorbance capacity (ORAC), β-carotene bleaching, and lipid peroxidation in liver microsomal fractions and mitochondria. Our results showed that DPPH radical scavenging activity and ORAC value increased with the number of phenolic hydroxyl groups, in the order EEC > procyanidin A1 ＞(＋)-catechin. On the other hand, using the β-carotene bleaching method, the bleaching activity was inhibited depending on the phenolic molecular weight, in the order (＋)-catechin>procyanidin A1 ＞ EEC. These results might be explained by differential affinity between polyphenols and substrates. In the lipid peroxidation test using rat liver mitochondria and microsomes, the antioxidant activity of both procyanidin A1 and EEC were greater than that of (＋)-catechin.
Penicillium expansum, a plant pathogenic fungus that infects apples, is known to produce patulin and has been shown to be involved in patulin contamination in apples. In this study, we examined the relationship between various apple components and the amount of accumulated patulin in different apple cultivars in order to determine the factors that mitigate patulin contamination. Interestingly, there was a significant correlation between the amount of accumulated patulin and the total polyphenol, chlorogenic acid, and asparagine contents in apples. However, the levels of aspartic acid and asparagine differed substantially within various portions of the apples. Hardness and sugar content of apples were inversely correlated with the amount of accumulated patulin. Thus, taken together, our results suggested that patulin did not accumulate in apple varieties that were harder and sweeter.
"Norabouna" is a leafy vegetable belonging to the Brassicaceae family and is a traditional cultivar in the western part of the Kanto region. However, the morphology of "Norabouna" in various local markets is not the same because local producers have their own seeds for production and they use different cultivation practices. Therefore, we evaluated the quality of "Norabouna" produced in different regions of Kanto by analyzing the morphology, composition, and toughness of flower stalks grown in different months (March, April, and May) by various producers. The analysis showed that the morphology of flower stalks differed according to the month of cultivation, thereby altering the condition of the packaged produce. This was one of the reasons for variation in the vegetable morphology between areas and producers, because they grew the plants in different months. In addition, the chemical composition and toughness of flower stalks varied between the growing months, areas of production, and the cultivation practice used by the producer. Moreover, compared with other leafy vegetables, "Norabouna" flower stalks had high ascorbic acid and sugar concentrations, giving them a pleasant taste. Therefore, "Norabouna" can potentially become a more widely produced leafy vegetable crop, but to achieve this, further studies are required to standardize the cultivation methods and stabilize the variations in the genetic stock.