In this study, soluble dietary fiber (SDF) prepared from baobab (Adansonia digitata) fruit pulp (BFP) was found to be composed of 82.9% acidic and 10.1% neutral sugar. When the methoxylated content of BFP-SDF was assayed, the proportion of methoxylated galacturonic acid was found to be 14.1%. The effect of BFP-SDF on the regulation of blood glucose level was examined in vitro and in vivo. BFP-SDF significantly reduced both glucose diffusion and permeation rates in cultured Caco-2cells. In oral glucose-tolerance tests conducted on Sprague-Dawley rats, compared to control rats administered 40% glucose solution, rats administered 40% glucose solution supplemented with 5% or 10% BFP-SDF showed significantly decreased postprandial blood glucose levels at 90 min and 120 min after administration. These results suggest that inclusion of BFP-SDF in the diet has a hypoglycemic effect in mammals, mainly due to a decrease in the diffusion of ingested glucose in the intestine.
Changes in the physicochemical and flavor characteristics of the Okinawan brown sugar "Kokuto" during storage for 21 months at ambient temperature were investigated. Changes in moisture content and water activity were small. Decrease in L* value and increase in the color value were observed, and differences in color characteristics among different kinds of Kokuto reduced with preservation. The color value of Kokuto increased concomitantly with a decrease in free amino acid content. The change in polyphenolic content was small. The antioxidant activity of Kokuto increased till the sixth month and then decreased afterwards. During storage, the content of sulfur-containing compounds showed a large decrease, while the contents of 3-ethyl-2, 5-dimethylpyrazine and dihydro-2-methyl-3 (2H) -furanone increased. These results suggest that the Maillard reaction progressed during storage of Kokuto at ambient temperature. The degree of scattering of volatile compounds varied according to the samples of newly produced Kokuto; however, the difference in scattering reduced with preservation.
The astringency of peeled persimmon fruit (Diospyros kaki Thunb.) after harvest can be removed during drying. Dehydration and astringency removal may also be induced via osmotic pressure by dipping the flesh in a concentrated sucrose solution. We examined the influence of dipping conditions and fruit maturity on the degree of dehydration and loss of astringency in persimmon flesh. Peeled fruits were individually dipped in a sucrose solution in a small plastic container that was sealed with a lid and kept under a constant temperature for several days. Dehydration of the flesh in 50°Brix sucrose solution progressed faster as the temperature increased from 35℃ to 50℃. However, the degree of dehydration was similar for all conditions after 7days of dipping. Dehydration progressed faster and the magnitude was greater as fruit maturity advanced. Although a loss of astringency did not occur in flesh dipped at 5℃, astringency disappeared rapidly in the flesh as the dipping temperature increased to between 20℃ to 50℃. The loss of astringency occurred more easily in mature than immature flesh. The ease of astringency loss varied among years. The total scores for product quality with respect to taste were higher for more mature fruits, except when they were overripe. These results suggest that the flesh from fruit at 80—100% maturity was suitable for processing. The fruit quality was different from traditional dry or semi-dry persimmon in the texture and was influenced by cutting and by the cultivar used.
Disulfide (SS) bond formation in dough is an important factor in bread making. In this paper, we examine the effects of recombinant protein disulfide isomerase (PDI) and endoplasmic reticulum oxidoreductase 1 (ERO1) on SS bonds in dough. The oxidation regeneration ability of ERO1 for PDI, which results in the formation of SS bonds in proteins, was analyzed. ERO1 obtained from wheat also had oxidation regeneration ability for PDI. In addition, the ability of SS bond formation to reduce ovomucoid degeneration increased about 3-fold with coexistent ERO1 and FAD compared with PDI alone. TaPDI, TaERO1, and FAD were reacted with acid-soluble wheat proteins prepared from hard flour and analyzed by diagonal electrophoresis. PDI has been suggested to form SS bonds in gliadin. Further, in bread-making tests using medium flour with poor suitability for bread making, the specific volume of 4.69cm3/g without TaPDI increased to 5.34cm3/g with addition of PDI, ERO1, and FAD, similar to that of hard wheat flour bread. From this result, it was possible to confirm the effect of using PDI in poor wheat flour on improving bread quality.