Abstract
Although buckwheat protein has high biological value, its digestibility is relatively low. We have found that this low digestibility is closely associated with its hypocholesterolemic activity in cholesterol-fed rats. This prompted us to investigate the possibility that buckwheat protein has dietary fiber-like effects, including anti-constipation, anti-obesity, and anti-tumor effects. The results we obtained supported this possibility. The silk protein, sericin, is also resistant to several proteases, and has a number of physiological functions such as strong water-holding capacity and antioxidant activity. These properties suggest that it would exert protective effects against constipation and colon carcinogenesis. In view of these facts, we postulated that low digestibility of dietary protein might improve the functions of the intestine and be beneficial for human health. By drawing an analogy with resistant starch, we propose that buckwheat protein and sericin might be “resistant proteins”, and discuss their physiological significance.
