Changes in Sugars, Starch and Trypsin Inhibitor Activity in Winged Bean (Psophocarpus tetragonolobus L.DC) During Seed Development

Abstract

Three cultivars of winged bean were analyzed for starch, sugars and trypsin inhibitor activity at different stages of seed maturity. The starch content ranged from 5.666.22% whereas sugar content varied from 4.40-6.53% in the matured seeds. The starch content increased as the seed maturation progressed from stage I (40 days after flowering) to stage II (50 days after flowering) followed by a decrease up to complete maturity. The total sugar content increased up to stage III (60 days after flowering) of maturity followed by a decrease during subsequent stages of maturation. The trypsin inhibitor activity increased as the seed maturation advanced from stage I to complete maturity. 7O(IV) days old were collected along with completely matured pods and chilled in a freezer (-20°C) for 24 hr. Subsequently, seeds were removed and dried at 60°C. The seeds were ground to pass through 100 mesh sieve and analyzed.

Seed polysaccharides of some winged bean varieties

“…No starch was detected in cultivar SLS 1, while the other four cultivare contained 1.9-4.6% starch in defatted seed meal (Table I). These values are consistent with those reported by Kute et al (1984) but differ from the value of 36.5% in defatted flour obtained by Sajjan and Wankhede (1981) and starch values reported by other workers (Garcia and Palmer, 180b; Ravindran and Palmer, 1984). Similarly Gajameragedara and Ravindran (1986) found no starch in the seeds of winged bean varieties SLS 1, SLS 3, and SLS 6, which were harvested at full maturity, but detected small amounts in the early stages of seed development.…”

“…Winged bean seeds also contain a high content (34%) of carbohydrates (Garcia and Palmer, 1980b). Though the constituent carbohydrates as determined by various researchers (Garcia and Palmer, 1980b; Sajjan and Wankhede, 1981;Kute et al, 1984;Ravindran and Palmer, 1984) have been presented as conflicting results, our earlier study on variety TPT-2 (Ravindran and Palmer, 1984) and that of Garcia and Palmer (1980b) has revealed the presence of 25-28% polysaccharides in the mature seeds with little or no starch as is the case with mature soybeans reported by Altschul (1958). The detergent fiber analysis of the winged bean seeds indicates a relatively low content (2-4%) of hemicelluloses and an unusually high content (12-14%) of cellulose or cellulose-like polysaccharides (Garcia and Palmer, 1980a).…”

Biochemical and nutritional assessment of tubers from 16 cultivars of sweet potato (Ipomoea batatas L.)

“…Among the cultivars, Wariyapola and L 9 showed high levels of trypsin inhibitory activity. Although direct comparison of analytical results on trypsin inhibitors is made difficult by differences in methodology and units of measurement, using a similar analytical technique, very much higher levels of trypsin inhibitor activity have been reported for grain legumes (110-2100 TIU/g of sample; Kute et al, 1984;Ravindran et al, 1987; Ravindran and Ravindran, 1988). Thus, the trypsin inhibitor levels present in sweetpotato tubers can generally be regarded as too low to cause any concern under practical situations.…”

Nutritional and Antinutritional Factors of Some Pulses Seed and Their Effects on Human Health

“…The human digestive system was created to handle a variety of plant and animal proteins through the process of digestion and elimination. Some plant and animal proteins or lectins are severely toxic to humans and cannot be eaten without causing death like those in Castor beans and some mushrooms [63]. The major antinutritional toxic factor limiting the use of pulses.…”