36E-16 |
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C. Sánchez-Moreno, E. Roldán, R. Lloria, B. De Ancos, and M. P. CANO. Plant Foods Science and Technology Dept., Instituto del Frío-CSIC, José Antonio Novais, 10, Ciudad Universitaria, Madrid, 28040, Spain World onion production has increased by at least 30% over past 10 years with current production being around 4 trillion tons, making it the second most important horticultural crop after tomatoes. Onions are a major source of dietary flavonoids in many countries. Onions have been found to have anticarcinogenic and antioxidant properties. Our objective was to characterize Spanish onion by-products from two different varieties (cv Recas, and cv Figueres) in order to evaluate their potential use from the food industry as a source of antioxidants, antimicrobials, dietary fiber and fructans. Raw material was supplied from different industries. They supplied the whole onion, and different industry by-products (juice, paste, and bagasse) from the two varieties selected. Total phenols were determined spectrophotometrically, and quercetin was determined by HPLC. The antioxidant activity was evaluated by the measurement of the DPPH• radical scavenging. Our results showed that the juice by-product had the lower content in total phenols and quercetin, and less antioxidant activity than the other two by-products (paste and bagasse) in the two varieties analyzed as well as in the mixture of both of them. In general, in the two varieties assayed the paste by-product had significantly higher total phenol and quercetin content, and significantly higher antioxidant activity. In general, within all the samples from the same variety, we found significant correlations between total phenol and quercetin contents and antioxidant parameters. It can be inferred that the outer leaves, which constitute the major parts of paste and bagasse by-products, represent the most useful by-products in order to obtain antioxidant bioactive compounds.
Session 36E, Fruit & Vegetable Products: General
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |