RESVERATROL, PEANUT SPROUT AND STILBENOIDS AS BIOACTIVE INGREDIENTS USED FOR DEVELOPMENT OF FUNCTIONAL FOODS OR DIETARY SUPPLEMENTS

摘要

Biosynthesis enhancements of resveratrol and some of other stilbenoids by peanut kernels as achieved by biotic and abiotic elicitations, such as germination, artificial microbial colonization, wounding, UV irradiation and ultrasonic treatment have been extensively investigated. Among those, germination of peanut kernels in preparation of peanut sprouts and enhancement of resveratrol biosynthesis has been demonstrated. Germination of a plant seed is an essential process in generation of a new plant. Normal and successful germination of plant seeds is a well-controlled biochemical and physiological process. During germination, seeds have to transform from their resistant status against circumstantial stress in winter to be physiologically active in the next spring and sufficiently prepared to initiate germinating. In markets, various bean sprouts are commercialized and commonly consumed as a vegetable. As emphasized, isoflavone and flavonoid contents and general nutritional attributes increase during soybean germination. When soybean, black soybean and lupin seeds were germinated for 48 h and applied as a dietary ingredient to feed rats, positive physiological effects have been noticed. Peanut sprouts germinated from peanut pods left in the field after harvest, in particular by machine harvesting, are occasionally collected and consumed as a vegetable by the peanut farmers. Lipids, proteins, amino acids and sugars undergo a series of physicochemical changes during peanut kernel germination. In addition to compositional changes, the antioxidative potency of peanut sprouts is higher than that of the kernels before germination. As conducted previously in our laboratory, when the water-soaked kernels of three peanut cultivars were germinated at 25°C and relative humidity 95% in the dark for 9 days, resveratrol contents increased significantly from the range of 2.3 to 4.5 μg/g up to the range of 11.7 to 25.7 μg/g depending upon peanut cultivar (Table 1). In comparison of resveratrol contents distributing in sprout components, resveratrol contents were highest in the cotyledons, slightly lower in the roots, and not detected in the stems. In addition to resveratrol, other stilbenoids including arachidin-1, arachidin-3 and isopentadienylresveratrol (IPD) (Figure 1) have been detected in the peanut kernels after incubated for germination and sliced for further incubation.