15C-19 |
Total phenolic content and antioxidant activity in asparagus (Asparagus officinalis) |
S. W. WANG1, J. R. Powers1, B. G. Swanson1, and J. Tang2. (1) Food Science and Human Nutrition, Washington State University, P.O. Box 2152, Pullman, WA 99165, (2) Department of Biological Systems Engineering, Washington State University, Pullman, WA 99164 Asparagus (Asparagus officinalis) is considered by many to be a food that can promote good health. However, the distribution of antioxidants and phenolics in asparagus spears has not been determined. This information may help food manufacturers develop products for functional use of under utilized portions of the asparagus spear. Our objective was to determine phenolic compounds and their antioxidant activity in different portions of the asparagus spear. Asparagus spears were cut into 3 parts: the basal part (0-7 cm from the cut end), the middle part (7-14 cm), and the apical part (14-22 cm). For total phenolics, the asparagus tissue was extracted with water. Total phenolics were measured using Folin-Ciocalteu reagent. For total antioxidant activity (TAA), asparagus samples were extracted with PBS buffer (polar) and ethyl acetate (non-polar). TAA was measured using the ABTS/HRP decoloration method. The concentration of total phenolics in the apical part of asparagus was significantly greater than the other two parts of asparagus. The total phenolics in the basal part of asparagus were 23.4 gallic acid equivalent mg/g, the middle part was 33.6 mg/g, and the apical part was 57.1 mg/g. The TAA of the basal part of asparagus was 3050 TROLEX equivalents nmoles/g, the middle part was 7600 nmoles/g, and the apical part was 10600 nmoles/g. In each part of the asparagus, the antioxidant activity of the polar fraction was much greater than the non-polar fraction. These results demonstrate a positive relationship between total phenolics content and TAA in asparagus. The apical portion of asparagus has the greatest quantities of total phenolics and TAA and may exhibit greater potential functional value as a health food.
Session 15C, Food Chemistry: Food composition and analysis
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