Hypolipidemic and Body Fat–Lowering Effects of Giant Embryo Brown Rice (Seonong 17 and Keunnunjami) in High‐Fat‐Fed Mice

The effects of giant embryo brown rice Seonong 17 and Keunnunjami, in comparison with that of ordinary normal brown rice, on the body weight and lipid profile in mice under a high‐fat diet condition were investigated. The animals were fed with experimental diets for eight weeks: normal control, high fat (HF), and high fat supplemented with normal brown rice, Seonong 17 rice, or Keunnunjami rice powder. Their body and fat weights, lipid profiles, lipogenic enzyme activities, and adipokine concentrations were determined. Significant differences between the animal groups were analyzed with Tukey's test (P < 0.05). A marked increase in the body weight and fat, plasma triglyceride and total cholesterol concentrations, and free fatty acid level were found in HF mice relative to the control group. On the other hand, diet supplementation with rice, particularly the giant embryo rice samples, significantly suppressed this high‐fat‐induced body weight gain and hyperlipidemia via regulation of lipogenesis and adipokine production. Both the Seonong 17 and Keunnunjami exhibited greater hypolipidemic and body fat–lowering effects than the normal brown rice. The results demonstrate that these giant embryo mutants may be beneficial as biomaterials for functional foods with antiobesity and hypolipidemic effects.     

Enzymatic synthesis of a selective inhibitor for alpha-glucosidases: alpha-acarviosinyl-(1-->9)-3-alpha-D-glucopyranosylpropen

Here, we describe the enzymatic synthesis of novel inhibitors using acarviosine-glucose as a donor and 3-alpha-D-glucopyranosylpropen (alphaGP) as an acceptor. Maltogenic amylase from Thermus sp. (ThMA) catalyzed the transglycosylation of the acarviosine moiety to alphaGP. The two major reaction products were isolated using chromatographies. Structural analyses revealed that acarviosine was transferred to either C-7 or C-9 of the alphaGP, which correspond to C-4 and C-6 of glucose. Both inhibited rat intestine alpha-glucosidase competitively but displayed a mixed-type inhibition mode against human pancreatic alpha-amylase. The alpha-acarviosinyl-(1-->7)-3-alpha-D-glucopyranosylpropen showed weaker inhibition potency than acarbose against both alpha-glycosidases. In contrast, the alpha-acarviosinyl-(1-->9)-3-alpha-D-glucopyranosylpropen exhibited a 3.0-fold improved inhibition potency against rat intestine alpha-glucosidase with 0.3-fold inhibition potency against human pancreatic alpha-amylase relative to acarbose. In conclusion, alpha-acarviosinyl-(1-->9)-3-alpha-D-glucopyranosylpropen is a novel alpha-glucosidase-selective inhibitor with 10-fold enhanced selectivity toward alpha-glucosidase over alpha-amylase relative to acarbose, and it could be applied as a potent hypoglycemic agent.     

DNA polymorphisms and genetic relationship among populations of <Emphasis Type="Italic">Acacia leucophloea</Emphasis> using RAPD markers

RAPD (randomly amplified polymorphic DNA) markers were employed to characterize polymorphisms among 5 provenances of Acacia leucophloea and to detect genetic relatedness of the species with 6 other acacias (A. holosericea, A. auriculiformis, A. mangium, A. dealbata, A. ferruginea, and A. nilotica) widely grown in India. Of 194 markers scored for the provenances, 29.38% exhibited polymorphism. Also, 326 markers were generated among 7 species of Acacia, accounting for 55.82% of the polymorphisms. The fifteen 10-mer primers employed were capable of producing 1–8 polymorphic bands for the provenances, and 6–17 for all seven species of Acacia. The genetic similarity coefficient based on Jaccard’s coefficient revealed that provenances Thirumangalam and Dharmapuri were closely related. The dendrogram based on a sequential agglomerative hierarchical non-overlapping (SAHN) clustering analysis grouped 4 provenances of A. leucophloea (Dharapuram, Thirumangalam, Pudukottai and Dharmapuri) into one cluster and the other provenance, Sendurai, into a separate cluster. The genetic similarity matrix for 7 Acacia species showed that A. nilotica and A. dealbata were distantly related, while A. holosericea and A. ferruginea were very closely related. Cluster analysis grouped the species of Acacias into 3 major groups of which A. dealbata alone formed a separate group. The RAPD markers generated 36 provenance-specific markers and 162 species-specific markers that could have strong applications for species identification and tree breeding programs for A. leucophloea and for other Acacia species included in this study.     

Protein Quality of Wheat Desirable for Making Fresh White Salted Noodles and Its Influences on Processing and Texture of Noodles

Protein characteristics of wheat flours from various wheat classes, and of commercial flours for making noodles, were evaluated to determine the effects of protein content and quality on processing and textural properties of white salted noodles, as well as to identify protein quality required for making white salted noodles. SDS sedimentation volume based on constant protein weight, mixograph mixing time, and proportions of salt‐ and alcohol‐soluble protein of three commercial flours for making noodles were more similar to those of hard wheat than to soft wheat flours. SDS sedimentation volume of commercial flours for making noodles based on constant protein weight ranged from 38.5 to 40.0 mL and was higher than those of most soft wheat flours. Mixograph mixing time and proportion of salt‐soluble protein of hard and commercial flours for making noodles were >145 sec and mostly <13.8%, respectively, while those of club and soft wheat flours were < 95 sec and >15.0%. Both protein content and protein quality, as determined by SDS sedimentation volume based on constant protein weight, mixograph mixing time, proportion of salt‐soluble protein, and score of HMW‐GS compositions correlated with optimum water absorption of noodle dough and hardness of cooked white salted noodles.     

Activity and Inhibition of Polyphenol Oxidase in Extracts of Bran and Other Milling Fractions from a Variety of Wheat Cultivars

Studies were conducted to compare polyphenol oxidase (PPO) specific activities in various milling fractions of a variety of wheat cultivars and determine the levels of activities in a number of cultivars from different localities and harvesting seasons. Substrate specificities were also investigated. Bran was singled out as the richest source of PPO activity, which may also influence the activity in the other milling fractions that are known to have some proportion of bran content. We showed by gel electrophoresis and spectrophotometrically that the protein responsible for PPO activity apparently exists as a single isoform in bran and that the observed enzyme activity is likely to be a tyrosinase type, not a laccase or peroxidase. The specific activity was not significantly different between the reduction shorts and break shorts from the same cultivar, indicating a similar level of bran contamination in these fractions. Very low levels of PPO activity were recorded in the flour of all cultivars studied. Bran was used, therefore, to determine the varietal differences in the PPO activities in a number of cultivars from different localities and seasons of harvest. Results showed that the most significant determinant of PPO activity was the genotype, and this may be influenced by seasonality. We also determined that, apart from substrate preferences by the PPO enzyme, some phenolic acids actually inhibit PPO. Furthermore, we found that bran of some cultivars extracted with acidified methanol inhibited PPO activity substantially, whereas other extracts had less inhibitory properties. Thus, these unknown compounds in wheat may inhibit endogenous PPO activity.