The Effects of a Mixture of Brown and Black Rice on Lipid Profiles and Antioxidant Status in Rats

Abstract: There is strong epidemiological evidence that whole-grain cereals protect the body against age-related diseases such as diabetes, cardiovascular diseases and some cancers. This may be due to the fibre and micronutrients in the outer layer and germ fractions of the grain acting together to combat oxidative stress, inflammation, hyperglycaemia and carcinogenesis. Oxidative stress is associated with these metabolic diseases. Whole-grain cereals are a good source of vitamin E, folates, phenolic acids, zinc, iron, selenium, copper, manganese, carotenoids, phytic acid, lignins, lignans, and alkylresorcinols, all of which have significant antioxidant potential in vitro. Phenolic acids such as ferulic acid are characteristic of cereals. They may scavenge free-radical oxygen species both in vitro and in vivo. Phenolics may also act in vivo by triggering gene induction/repression via cell signalling through transcription factors. Whole-grain cereals are also a good source of betaine, choline and sulphur amino acids that can improve antioxidant status. Betaine, which accounts for about 1% (w/w) of the bran fraction in wheat, acts as a methyl donor that may decrease hyperhomocysteinaemia, a cardiovascular risk factor, but it has been neglected. Cereals and cereal products are antioxidative in vitro, as are most fruits and vegetables. The in vitro antioxidant capacity of cereals and their constituent fractions is significantly correlated with their polyphenol content, except for maize. However, the in vitro antioxidant capacity of cereals is only an approximate reflection of their in vivo antioxidant effect due to differences in antioxidant solubility/bioavailability within the digestive tract and the metabolism/conjugation of compounds such as polyphenols. During digestion, the antioxidant capacity of cereals is increased and is likely to provide a favourable antioxidative environment for the epithelium tract, notably in the large intestine. Most of the studies performed on animals have been concerned with the antioxidant property of coloured rice, especially black rice and its anthocyanin fraction, showing a positive effect on some antioxidant biomarkers. Those very few studies that have been done on humans have shown that wheat bran and rye product supplements have no effect on antioxidant status, while a black rice pigment fraction and an avenanthramide-enriched mixture extracted from hulled oats have a positive effect. In vivo studies are therefore needed to further explore the real antioxidant potential of cereals.

Abstract: The pigmented rice has been consumed in China, Japan, and Korea for a long time. It has been used for strengthening kidney function, treating anemia, promoting blood circulation, removing blood stasis, treating diabetes, and ameliorating sight in traditional Chinese medicine. The extracts from pigmented rice are used as natural food colorants in bread, ice cream, and liquor as well as functional food. The pigmented rice is mainly black, red, and dark purple rice, and contains a variety of flavones, tannin, phenolics, sterols, tocols, γ-oryzanols, amino acids, and essential oils. Anthocyanins are thought as major functional components of pigmented rice. Several anthocyanins have been isolated and identified from the pigmented rice, including cyanidin 3-glucoside, cyanidin 3-galactoside, cyanidin 3-rutinoside, cyanidin 3,5-diglucoside, malvidin 3-galactoside, peonidin 3-glucoside, and pelargonidin 3,5-diglucoside. This review provides up-to-date coverage of pigmented rice in regard to bioactive constituents...

Abstract: HPLC analysis of dehulled red, black and non-colored indica and japonica rice subspecies revealed significant differences in the contents of the anthocyanins cyanidin-3-glucoside and peonidin-3-glucoside. The rice materials were subjected to a comparative capillary gas chromatography-based metabolite profiling approach. The employed extraction and fractionation protocol enables the analysis of a broad spectrum of lipophilic and hydrophilic low molecular weight constituents from different chemical classes. The method covers not only primary metabolites (e.g. sugars, fatty acids) but also nutritionally relevant constituents (e.g. α-tocopherol, γ-aminobutyric acid). Statistical assessment of the data via principal component analysis and agglomerative hierarchical clustering revealed a distinct grouping of the different colored rice subspecies on the basis of their metabolite profiles. Compared to non-colored and red rice, black rice exhibited, in particular, higher levels of fatty acid methyl esters, free fatty acids, organic acids and amino acids.

Abstract: Background/Aims: The purpose of the current study is to investigate the influence of germinated giant embryonic rice consumption on the lipid metabolism and antioxidant system in ra

Abstract: The effects of the type of solvolytic solution and number of extraction steps on the recovery of free phenolics, anthocyanins and proanthocyanidins from different rice samples were evaluated. Moreover, bound phenolic acids were determined as a function of enzymatic and/or alkaline hydrolysis treatment of the rice residue obtained after the extraction of free phenolics. The Acetone/Water (70:30 v/v) was the most effective solvolytic solution for extracting free phenolics from pigmented rice, as well as anthocyanins from black and wild rice, and proanthocyanidins from red rice. The application of three extraction steps increased the recovery of free phenolics up to 10%. The adoption of an enzymatic treatment, with α-amylase in order to reduce the paste viscosity of the residue, increased the extractability of bound phenolics. α-Amylase at 37°C during 15min followed by an alkaline hydrolysis at 37°C was the best treatment for the recovery of bound phenolics.

Abstract: A protein determination method which involves the binding of Coomassie Brilliant Blue G-250 to protein is described. The binding of the dye to protein causes a shift in the absorption maximum of the dye from 465 to 595 nm, and it is the increase in absorption at 595 nm which is monitored. This assay is very reproducible and rapid with the dye binding process virtually complete in approximately 2 min with good color stability for 1 hr. There is little or no interference from cations such as sodium or potassium nor from carbohydrates such as sucrose. A small amount of color is developed in the presence of strongly alkaline buffering agents, but the assay may be run accurately by the use of proper buffer controls. The only components found to give excessive interfering color in the assay are relatively large amounts of detergents such as sodium dodecyl sulfate, Triton X-100, and commercial glassware detergents. Interference by small amounts of detergent may be eliminated by the use of proper controls.

Abstract: A method for estimating the cholesterol content of the serum low-density lipoprotein fraction (Sf0-20) is presented. The method involves measurements of fasting plasma total cholesterol, triglyceride, and high-density lipoprotein cholesterol concentrations, none of which requires the use of the preparative ultracentrifuge. Comparison of this suggested procedure with the more direct procedure, in which the ultracentrifuge is used, yielded correlation coefficients of .94 to .99, depending on the patient population compared.

Abstract: Background: The effects of dietary soluble fibers on blood cholesterol are uncertain. Objective: This meta-analysis of 67 controlled trials was performed to quantify the cholesterol-lowering effect of major dietary fibers. Design: Least-squares regression analyses were used to test the effect on blood lipids of pectin, oat bran, guar gum, and psyllium. Independent variables were type and amount of soluble fiber, initial cholesterol concentration, and other important study characteristics. Results: Soluble fiber, 2‐10 g/d, was associated with small but significant decreases in total cholesterol [ 20.045 mmol · L 21 ·g soluble fiber 21 (95% CI: 20.054, 20.035)] and LDL cholesterol [20.057 mmol · L 21 ·g 21 (95% CI: 20.070, 20.044)]. The effects on plasma lipids of soluble fiber from oat, psyllium, or pectin were not significantly different. We were unable to compare effects of guar because of the limited number of studies using 2‐10 g/d. Triacylglycerols and HDL cholesterol were not significantly influenced by soluble fiber. Lipid changes were independent of study design, treatment length, and background dietary fat content. Conclusions: Various soluble fibers reduce total and LDL cholesterol by similar amounts. The effect is small within the practical range of intake. For example, 3 g soluble fiber from oats (3 servings of oatmeal, 28 g each) can decrease total and LDL cholesterol by <0.13 mmol/L. Increasing soluble fiber can make only a small contribution to dietary therapy to lower cholesterol. Am J Clin Nutr 1999;69:30‐42.

Abstract: The AIN-93 rodent diets were formulated to substitute for the previous version (AIN-76A) and to improve the performance of animals that consume them. They are called AIN-93G, formulated for growth, and AIN-93M, for maintenance. Major changes included substituting cornstarch for sucrose and soybean oil for corn oil and increasing the amount in order to supply both essential fatty acids (linoleic and linolenic). L-Cystine was substituted for DL-methionine to supplement the casein component. The mineral mix was reformulated to lower the amounts of phosphorus, manganese and chromium, to increase the amount of selenium, and to add molybdenum, silicon, fluoride, nickel, boron, lithium and vanadium. The amounts of vitamins E, K-1 and B-12 were increased over those in the AIN-76A vitamin mix. The AIN-93G diet contains 200 g of casein and 70 g of soybean oil/kg diet. The maintenance diet (AIN-93M) contains 140 g of casein and 40 g of soybean oil/kg diet. The 1993 diets have a better balance of essential nutrients than the 1976 diet and are better choices for studies with laboratory rodents.

Abstract: Objective. —To examine prospectively the relationship between dietary fiber and risk of coronary heart disease. Design. —Cohort study. Setting. —In 1986, a total of 43 757 US male health professionals 40 to 75 years of age and free from diagnosed cardiovascular disease and diabetes completed a detailed 131 -item dietary questionnaire used to measure usual intake of total dietary fiber and specific food sources of fiber. Main Outcome Measure. —Fatal and nonfatal myocardial infarction (Ml). Results. —During 6 years of follow-up, we documented 734 cases of Ml (229 were fatal coronary heart disease). The age-adjusted relative risk (RR) for total Ml was 0.59 (95% confidence interval [CI], 0.46 to 0.76) among men in the highest quintile of total dietary fiber intake (median, 28.9 g/d) compared with men in the lowest quartile (median, 12.4 g/d). The inverse association was strongest for fatal coronary disease (RR, 0.45; 95% CI, 0.28 to 0.72). After controlling for smoking, physical activity and other known nondietary cardiovascular risk factors, dietary saturated fat, vitamin E, total energy intake, and alcohol intake, the RRs were only modestly attenuated. A 10-g increase in total dietary fiber corresponded to an RR for total Ml of 0.81 (95% CI, 0.70 to 0.93). Within the three main food contributors to total fiber intake (vegetable, fruit, and cereal), cereal fiber was most strongly associated with a reduced risk of total Ml (RR, 071; 95% CI, 0.55 to 0.91 for each 10-g increase in cereal fiber per day). Conclusions. —Our results suggest an inverse association between fiber intake and Ml. These results support current national dietary guidelines to increase dietary fiber intake and suggest that fiber, independent of fat intake, is an important dietary component for the prevention of coronary disease. (JAMA. 1996;275:447-451)