Effects of cake made from whole soy powder on postprandial blood glucose and insulin levels in human subjects.

We investigated the glycemic index (GI) and the insulinemic index (II) of cake made from whole soy powder (SBC) and the suppressive effects of SBC on the postprandial blood glucose and insulin by other carbohydrate foods. Furthermore, breath hydrogen excretion was simultaneously investigated. Twenty subjects were given 114 g SBC, 144 g cooked paddy-rice, and 60 g SBC with 144 g cooked paddy-rice in random order using a within-subject, repeated-measures design. Blood and end-expiratory gas were collected at the indicated periods after ingestion. The GI and the II of SBC were 22+/-6 and 48+/-29, respectively. The elevation of blood glucose by cooked paddy-rice was significantly suppressed by the addition of 60 g SBC, although the insulin secretion did not decrease. Breath hydrogen excretion by the addition of SBC to 144 g cooked paddy-rice was not significantly increased in comparison with cooked paddy-rice alone. SBC was of low GI and low II, but the postprandial insulin secretion in response to cooked paddy-rice was not suppressed.

Inhibitory Effects of Partially Decomposed Alginate on Production of Glucan and Organic Acid by Streptococcus sobrinus 6715.

Our previous study has already clarified that partially decomposed alginate (Alg53) by Vibrio alginolyticus SUN53 has a competitive inhibitory effect on sucrase. The objective of this study is to evaluate the influence of Alg53 on the production of glucan from sucrose by glucosyltransferase and acid from glucose by Streptococcus sobrinus 6715. Glucosyltransferase was prepared from cultural medium of S. sobrinus using ultrafiltration and hydroxyapatite chromatography. In order to examine the inhibitory effect of Alg53 for production of glucan by GTase, partially purified GTase, sucrose and Alg53 solution were incubated at 37 degrees C. The influence of Alg53 on the production of acid from glucose was evaluated by a degree of pH decline during the incubation for 60 min. The original Alg53 solution markedly inhibited to 21% of the synthesis of water-insoluble glucan from sucrose and that of 10-fold diluted of Alg53 solution was 23%. However, the production of water-soluble glucan from sucrose by GTase was hardly affected by Alg53. Furthermore, Alg53 suppressed dose-dependently pH decline by organic acid converted from glucose. These results suggest that Alg53 is expected as a functional food material which prevents or reduces dental caries.