Powders of α-lipoic acid (ALA)/cyclodextrin (CD) complexes containing 9-24% (w/w) ALA were prepared to improve the gastrointestinal absorption of ALA. ALA and the ALA/CD complexes, corresponding to 30 mg/kg of body weight of ALA in rats and 600 mg of ALA in humans, were orally administered under fasting conditions. In rats, the area under the ALA plasma concentration/time-course curve from 0 to 3 h (AUC 0-3 h) for the ALA/G2-β-CD® complex was larger than that for ALA alone. In humans, after administration of 3 ALA/CD complexes with γ-CD, G2-β-CD® and Isoeleat®P, the ALA plasma concentration value 0.5 h after administration of the ALA/G2-β-CD® complex was significantly higher (p < 0.05) than that for ALA alone, and the AUC 0-3 h value for the ALA/G2-β-CD® complex was 1.4 times larger than that for ALA alone, although the difference was not significant. We suggest that the water-soluble ALA/G2-β-CD® complex powder can enhance ALA absorption in rats and humans.
Hydrolysis of crystalline cellulose is a crucial step in utilization of cellulosic biomass and is generally the bottleneck in the biochemical process. The combination of pre-treatment and the use of suitable enzymes is the key to effective saccharification, and ammonia pretreatment is a promising technique to enhance the velocity and yield in saccharification of crystalline cellulose. In the present study, we heterologously expressed recombinant cellobiohydrolase II from Phanerochaete chrysosporium (PcCel6A) in Pichia pastoris. We then employed surface density analysis to compare the velocities of degradation of crystalline cellulose IIII, which was prepared from algal cellulose I by supercritical ammonia treatment, by the recombinant enzyme and Trichoderma reesei cellobiohydrolase I (TrCel7A). The hydrolytic velocity of crystalline cellulose IIII by PcCel6A was approximately 4 times faster than that by TrCel7A, though velocity of cellulose I degradation by PcCel6A was almost half of that by TrCel7A. Since adsorption of both enzymes on cellulose IIII is no more than twice that on cellulose I, we speculate that the enhanced hydrolysis of cellulose IIII by PcCel6A than TrCel7A is not simply due to the increased surface area, but also reflects higher accessibility of cellulose IIII to PcCel6A.
Here we examined the properties of endosperm starches and the physical properties of cooked rice from four cultivars of Japanese upland rice containing M-type amylopectin (Chikanarijyun1, Kairyo13, Mogamichikanari1 and Hokkaiakage); S-type Nipponbare and L-type Kasalath served as standards. The amylopectin chain ratio (ACR ; ratio of the short chains of DP ≤ 10 to the short and intermediate chains of DP ≤ 24) of M-type amylopectin was higher than L-type amylopectin, and lower than S-type amylopectin. The degree of disintegration of rice grains in 5 M urea solution was in the order Nipponbare > M-type amylopectin > Kasalath. Specifically, the disintegration score of rice grains decreased as the ACR decreased. The apparent amylose (AAM) contents were in the order Kasalath > M-type amylopectin, except Kairyo13 > Nipponbare > Kairyo13. These results indicated that there was no relationship between the AAM contents and ACR. The hardness of freshly cooked and stale rice was in the order Kasalath > M-type amylopectin > Nipponbare. The stickiness of freshly cooked rice was in the order Nipponbare > Kairyo13 > M-type amylopectin, except Kairyo13 > Kasalath and that of stale rice was in the order Nipponbare > M-type amylopectin > Kasalath. The stickiness of freshly cooked rice of Kairyo13 was the highest in the M-type amylopectin cultivars, because it had the lowest AAM content in all cultivars. Freshly cooked rice of Kairyo13 was harder and less sticky compared with that of Nipponbare. It was possible that the ACR of Kairyo13 was lower than that of Nipponbare.
A mono sodium glutamate (GluNa)-compounded starch prepared by autoclaving a mixture of tapioca starch and GluNa under limited water content was applied to improve the physical properties of the fried coatings of Vienna sausages. The GluNa-compounded starch could reduce the total and surface water contents of the fried coatings, retard retrogradation, and maintain a fragile porous structure over 24-48 h storage at 25°C and a relative humidity of 70%. Crispness of the fried coatings also could be enhanced with the GluNa-compounded starch, and was maintained during 24 h-storage. It is thus concluded that the GluNa-compounded starch could be effectively applied to improve the crispy texture of fried coatings.
Batch-type cone-plate rotational viscometry was performed for 4.0% (carbohydrate content) dispersions of nonglutinous corn and wheat starches gelatinized by NaOH solutions at 20°C. The flow characteristics at different NaOH concentrations and the growth process of viscosity at a constant NaOH concentration were studied. Power-law model analysis of the samples stored for a certain time after adding NaOH solutions of different concentrations, showed that the corn and wheat starch samples showed an apparently dilatant flow in the 0.171-0.183 and 0.122-0.137 M regions respectively, in which an increase of NaOH concentration greatly enhanced the consistency coefficient. Then, the storage-time dependence of viscosity was investigated for batch samples gelatinized by 0.170 M (corn) and 0.133 M (wheat) NaOH solutions. For both cases, viscosity was found to increase exponentially with time in the early stage of gelatinization. This exponential growth of viscosity was theoretically described by the kinetic model, composed of the first-order reaction rate equation for the degree of gelatinization and the fluidity-type mixing rule for ungelatinized and gelatinized parts. Although some quantitative differences existed, the present results for corn and wheat starches were qualitatively the same with those previously observed for rice starch, and hence supported that such a novel growth process of viscosity has a physicochemical origin, not being characteristic of a specific plant origin.
Five cassava landraces were collected from central west and central south Brazil and from the Amazon region and planted in the same field under the same climatic conditions. Starch samples were isolated and characterized to reveal the relationship between the structure and physical and rheological properties of each starch. The apparent amylose contents varied between 21.4-25.0%, and the starch samples displayed a C-type XRD pattern. Moreover, the branch chain-length distribution patterns of amylopectins were similar and DSC thermograms of each sample showed the main endothermic gelatinization peak with a shoulder at a lower temperature. However, the thermogram of a 24-h digest used crystalline α-amylolysate of starch sample from cassava landraces (no. 163) was completely different from the other starch samples hydrolyzed for the same length of time. The pasting properties and dynamic viscoelasticity of sample no. 163 were also unique amongst the samples.