The antioxidant activity of 80% ethanol and 70% acetone extracts of stems from red and white grapes (Vitis vinifera) used in wine industry were evaluated to determine their feasibility as natural antioxidants. The res...The antioxidant activity of 80% ethanol and 70% acetone extracts of stems from red and white grapes (Vitis vinifera) used in wine industry were evaluated to determine their feasibility as natural antioxidants. The results showed that all grape stem extracts were rich in total polyphenolic compounds and flavanols and had clear antioxidant activities. The free radical-scavenging capacity of the extracts was determined using the DPPH (2,2-diphenyl-1-picrylhydrazyl) method. The extracts obtained from red grape stem present EC50 values of 0.14 g dm/g DPPH (acetone extract) and 0.20 g dm/g DPPH (ethanol extract) while the extracts obtained from white grape stem present EC50 values of 0.26 g dm/g DPPH (acetone extract) and 0.37 g dm/g DPPH (ethanol extract). There are significant correlations between the total content of polyphenols and the antioxidant activity (R2 = 0.9352) and between the flavanols content and the antioxidant activity (R2 = 0.9404) of the grape stem extracts obtained.展开更多
An understanding of physiological disorders associated with ripening of fruits triggered by abiotic stress relies on anatomical and physico-chemical analyses, as it provide insights into their origin and probable caus...An understanding of physiological disorders associated with ripening of fruits triggered by abiotic stress relies on anatomical and physico-chemical analyses, as it provide insights into their origin and probable causes. The objective of this study was to analyze different ripening disorders of grape (Vitis vinifera L.) berries by dissecting their morpho-anatomy, shriveling nature, and composition. Four well-defined disorders—sunburn, prolonged dehydration (PD), late-season bunch stem necrosis (LBSN), and berry shrivel (BS) were analyzed in field-grown grapevines of the cultivar Cabernet Sauvignon. Early bunch stem necrosis (EBSN) that occurred before ripening was also included in the study. Unlike healthy spherical berries, the pericarp of disordered berries except for sunburn shriveled causing concomitant reductions in fresh weight and volume. The exocarp of PD berries developed well-ordered indentations as distinct from the wrinkles in LBSN berries, whereas BS berries were flaccid with numerous skin folds. The epicuticular wax occurred as upright platelets in all shrivel forms excluding the sun-exposed hemisphere of sunburned berries. A chlorophyllous inflorescence framework persisted in all shrivel forms but in LBSN, wherein the necrotic regions developed tylosis. Unlike the translucent mesocarp of healthy, sunburned, and PD berries, the mesocarp was collapsed in BS and LBSN berries, nevertheless all had well-developed seeds. The composition of healthy berries was optimal, whereas the disordered berries were compositionally distinct from each other, which as a whole differed from the healthy berries. The BS berries had the lowest sugar content, and although sugar concentration was higher in LBSN, sunburned and PD berries, sugar amount per berry was highest in the healthy berries, the same was true for hexoses. Healthy and BS berries exhibited highest amounts of tartaric acid followed by sunburn and PD berries, whereas the LBSN berries had the lowest values. Conversely, healthy and PD berries had the highest amounts of malic acid followed by LBSN, sunburn and BS berries, which collectively displayed similar amounts. The PD berries exhibited the highest calcium content followed by LBSN, healthy, and finally BS and sunburned berries. A linear relationship existed between potassium (K) and pH of the berries. The PD berries had the highest amounts of K followed by healthy, sunburn, LBSN, and BS berries. Overall, the results reported here provided combined morpho-anatomical and compositional analyses of different shrivel types that occurred during a single growing season. Such analysis is needed to make a progress on understanding these ripening disorders culminating in the development of remedial measures.展开更多
文摘The antioxidant activity of 80% ethanol and 70% acetone extracts of stems from red and white grapes (Vitis vinifera) used in wine industry were evaluated to determine their feasibility as natural antioxidants. The results showed that all grape stem extracts were rich in total polyphenolic compounds and flavanols and had clear antioxidant activities. The free radical-scavenging capacity of the extracts was determined using the DPPH (2,2-diphenyl-1-picrylhydrazyl) method. The extracts obtained from red grape stem present EC50 values of 0.14 g dm/g DPPH (acetone extract) and 0.20 g dm/g DPPH (ethanol extract) while the extracts obtained from white grape stem present EC50 values of 0.26 g dm/g DPPH (acetone extract) and 0.37 g dm/g DPPH (ethanol extract). There are significant correlations between the total content of polyphenols and the antioxidant activity (R2 = 0.9352) and between the flavanols content and the antioxidant activity (R2 = 0.9404) of the grape stem extracts obtained.
文摘An understanding of physiological disorders associated with ripening of fruits triggered by abiotic stress relies on anatomical and physico-chemical analyses, as it provide insights into their origin and probable causes. The objective of this study was to analyze different ripening disorders of grape (Vitis vinifera L.) berries by dissecting their morpho-anatomy, shriveling nature, and composition. Four well-defined disorders—sunburn, prolonged dehydration (PD), late-season bunch stem necrosis (LBSN), and berry shrivel (BS) were analyzed in field-grown grapevines of the cultivar Cabernet Sauvignon. Early bunch stem necrosis (EBSN) that occurred before ripening was also included in the study. Unlike healthy spherical berries, the pericarp of disordered berries except for sunburn shriveled causing concomitant reductions in fresh weight and volume. The exocarp of PD berries developed well-ordered indentations as distinct from the wrinkles in LBSN berries, whereas BS berries were flaccid with numerous skin folds. The epicuticular wax occurred as upright platelets in all shrivel forms excluding the sun-exposed hemisphere of sunburned berries. A chlorophyllous inflorescence framework persisted in all shrivel forms but in LBSN, wherein the necrotic regions developed tylosis. Unlike the translucent mesocarp of healthy, sunburned, and PD berries, the mesocarp was collapsed in BS and LBSN berries, nevertheless all had well-developed seeds. The composition of healthy berries was optimal, whereas the disordered berries were compositionally distinct from each other, which as a whole differed from the healthy berries. The BS berries had the lowest sugar content, and although sugar concentration was higher in LBSN, sunburned and PD berries, sugar amount per berry was highest in the healthy berries, the same was true for hexoses. Healthy and BS berries exhibited highest amounts of tartaric acid followed by sunburn and PD berries, whereas the LBSN berries had the lowest values. Conversely, healthy and PD berries had the highest amounts of malic acid followed by LBSN, sunburn and BS berries, which collectively displayed similar amounts. The PD berries exhibited the highest calcium content followed by LBSN, healthy, and finally BS and sunburned berries. A linear relationship existed between potassium (K) and pH of the berries. The PD berries had the highest amounts of K followed by healthy, sunburn, LBSN, and BS berries. Overall, the results reported here provided combined morpho-anatomical and compositional analyses of different shrivel types that occurred during a single growing season. Such analysis is needed to make a progress on understanding these ripening disorders culminating in the development of remedial measures.
