Effect of Bran Extract from Pigmented Rice Superjami on the Lipid and Glucose Metabolisms in a Postmenopause‐Like Model of Ovariectomized Rats

The effect of rice bran ethanolic extract from Superjami, a new blackish‐purple pigmented cultivar, on the lipid and glucose metabolisms in a postmenopausal‐like model of ovariectomized rats was investigated. Sprague‐Dawley female rats were subjected to either bilateral ovariectomy or a sham operation and randomly divided into three dietary groups (n = 6): sham‐operated fed with normal diet (SHAM), ovariectomized fed with normal diet (OVX‐AIN76), and ovariectomized fed with normal diet supplemented with Superjami bran extract (OVX‐SJ). The OVX‐AIN76 group showed significantly higher body weight, triglyceride, total cholesterol, blood glucose, and insulin than the SHAM group. On the other hand, supplementation of Superjami bran extract markedly reduced the body weight gain and improved the lipid and glucose profiles in ovariectomized rats through inhibition of hepatic lipogenesis and adipokine production and modulation of glucose‐regulating enzyme activities. These findings demonstrate that extracts from Superjami bran may be useful in the prevention and management of postmenopause‐induced hyperlipidemia and hyperglycemia.     

Cholesterol Response and Foam Cell Formation in Hamsters Fed Rice Bran,Oat Bran,and Cellulose + Soy Protein Diets With or Without Added Vitamin E

Four-week-old male golden Syrian hamsters were fed diets containing cellulose (control, CC), cellulose + soy protein (CS), CS + vitamin E, (CSE), rice bran (RB), RB + vitamin E (RBE), oat bran (OB), and OB + vitamin E (OBE) for six weeks (n = 10/treatment). Diets contained (by weight) 10% total dietary fiber, 3% N, 20% fat, 0.5% cholesterol, and some diets had an additional 0.1% vitamin E. After six weeks, RB and OB diets resulted in significantly higher weight gain than the CC diet. Plasma low-density lipoprotein cholesterol (LDL-C) values and the LDL-C/high-density lipoprotein cholesterol ratio in hamsters fed CSE, RBE, OB, and OBE diets were significantly lower than in those fed CC diet. There were no significant differences in total plasma cholesterol values among the hamsters fed any of the diets. Liver cholesterol in animals fed OB and OBE diets was significantly lower than in all other groups. Foam cell areas in the inner bend of the aortic arch in animals fed all treatment diets were significantly reduced when compared with that in animals fed CC diet. The level of additional dietary vitamin E did not result in further significant reductions in foam cell area. The results of this study suggest that diets containing rice bran, oat bran, or soy protein significantly reduced the development of atherosclerosis in hypercholesterolemic hamsters.     

Hypoglycemic effects of a phenolic acid fraction of rice bran and ferulic acid in C57BL/KsJ-db/db mice

Rice bran contains many phenolic acids, the most abundant of which is the antioxidant, ferulic acid (FA). We evaluated the hypoglycemic effects of a phenolic acid fraction (the ethyl acetate fraction, EAE) of rice bran and of FA in C57BL/KsJ db/db mice. Type 2 diabetic mice were allocated to a control group, an EAE group, or an FA group. Animals were fed a modified AIN-76 diet, and EAE or FA was administered orally for 17 days. There was no significant difference in body weight gain between groups. Administration of EAE and FA significantly decreased blood glucose levels and increased plasma insulin levels. EAE or FA groups had significantly elevated hepatic glycogen synthesis and glucokinase activity compared with the control group. Plasma total cholesterol and low density lipoprotein (LDL) cholesterol concentrations were significantly decreased by EAE and FA administration. These findings suggest that EAE and FA may be beneficial for treatment of type 2 diabetes because they regulate blood glucose levels by elevating glucokinase activity and production of glycogen in the liver.     

Effects of Chinese and North American Wild Rice on Blood Lipids,Oxidative Stress,and Inflammation Factors in Hyperlipidemic Rats

The aim of the present study was to compare the effects of replacing processed rice and wheat starch with Chinese and North American wild rice as the chief source of dietary carbohydrates in rats fed high levels of saturated fat and cholesterol. The study consisted of five groups: low‐fat diet, high fat/cholesterol diet, city diet, North American wild rice diet, and Chinese wild rice diet. At the end of eight weeks of the diet regimen, the North American and Chinese wild rice diets suppressed the increase in serum triglyceride and total cholesterol but also decreased the high‐density lipoprotein cholesterol level. In addition, rats fed either the North American or Chinese wild rice diet suppressed the build‐up of oxidative stress by improving total antioxidant capacity, increasing superoxide dismutase activity, and reducing malondialdehyde concentration. In contrast, rats fed with the high fat/cholesterol diet and city diet had increased concentrations of high‐sensitivity C‐reactive protein (hs‐CRP) and tumor necrosis factor α (TNF‐α) compared with the low‐fat diet; rats fed with the Chinese wild rice diet had a significantly decreased serum hs‐CRP protein and TNF‐α concentration. Higher serum hs‐CRP levels were verified in the city diet group compared with North American wild rice diet group. These findings illustrate that both North American wild rice and Chinese wild rice are effective in suppressing hyperlipidemia, oxidative stress, and inflammation in rats even when the diet consumed is high in fat and cholesterol.     

Effect of Extrusion on Hypocholesterolemic Properties of Rice,Oat, Corn,and Wheat Bran Diets in Hamsters

Brans from rice, oats, corn, and wheat were cooked in a twin-screw extruder at either high or low energy input, and their cholesterol-lowering effects were compared with those of unprocessed brans when fed to four-week-old male golden Syrian hamsters (n = 10 per treatment) for three weeks. Peanut oil was added to oat, corn, and wheat bran during the extrusion process to match the oil content of rice bran. Diets contained 10% total dietary fiber, 10.3% fat, 3% nitrogen, and 0.3% cholesterol. Plasma and liver cholesterol and total liver lipids were significantly lower with low-energy extruded wheat bran compared with unprocessed wheat bran. Extrusion did not alter the hypocholesterolemic effects of rice, oat, or corn brans. Plasma and liver cholesterol levels with corn bran were similar to those with oat bran. Relative cholesterol-lowering effects of the brans, determined with pooled (extruded and unextruded) bran data, were rice bran > oat bran > corn bran > wheat bran. Rice bran diets resulted in significantly lower levels of total plasma cholesterol and very low density lipoprotein cholesterol compared with all other brans. Total liver cholesterol and liver cholesterol concentrations (mg/g) were significantly lower with high-energy extruded rice bran compared with the cellulose control group. Plasma cholesterol and total liver cholesterol values with low-energy extruded wheat bran were similar to those with rice bran (unextruded or extruded) diets. Lowered cholesterol with rice bran diets may result in part from greater lipid and sterol excretion with these diets. Results with low-energy extruded wheat bran suggest that this type of processing may improve the potential for lowering cholesterol with wheat bran products.     

Nutritional quality of sesame seed protein fraction extracted with isopropanol

The nutritional effect of diet containing decorticated sesame seed extracted with isopropanol (DSS-Iso) was evaluated on growth performance, food efficiency ratio, plasma and tissue lipid profile, plasma protein content, and erythrocyte membrane lipid profile of rats on a comparative basis with diets containing casein (control), soybean meal, and decorticated sesame seed extracted with hexane (DSS-Hex). Rats fed a DSS-Iso-based diet showed body weight gain and food efficiency ratio similar to those of the control groups fed diets prepared with casein, soybean meal, and DSS-Hex. However, dietary proteins exerted a separate effect on plasma lipid concentrations of the rats. Rats fed a DSS-Iso-based diet showed significant decreases in plasma total cholesterol (p < 0.01), triglyceride (p < 0.01), and VLDL+LDL cholesterol (p < 0.01) concentrations in comparison to the rats fed diet containing casein. No significant differences in plasma lipid concentrations were observed for the rats fed diets prepared with soybean meal, DSS-Hex, and DSS-Iso. Rats fed the different dietary proteins did not show much variation in plasma proteins, liver lipids, and erythrocyte membrane lipid concentrations, which suggests that DSS-Iso could be a suitable edible protein like casein or soybean meal.     

Dietary fibers from mushroom sclerotia. 4. In vivo mineral absorption using ovariectomized rat model

The effect of three novel dietary fibers (DFs) prepared from mushroom sclerotia, namely, Pleurotus tuber-regium, Polyporus rhinocerus, and Wolfiporia cocos, on calcium and magnesium absorption was evaluated in ovariectomized (OVX) rats fed with sclerotial DF based and low Ca (0.3%) diets for 14 days. The animals in the W. cocos DF diet group possessed significantly (p < 0.05) higher levels of cecal total short-chain fatty acids (204 mumol/g of cecal content) and had an acidic pH (5.88) in their cecum when compared with those of the cellulose control group. Such an acidic environment was found to promote the ionization of the unabsorbed Ca and Mg in their cecum, which in turn significantly (p < 0.05) increased the concentrations of cecal soluble Ca (2.56-fold) and Mg (1.22-fold). Besides, the apparent Ca and Mg absorptions of the W. cocos DF group were also significantly (p < 0.05) enhanced (Ca, 16.5%; Mg, 15.3%) together with significantly (p < 0.05) higher serum Ca (3.61 mmol/L) and Mg (1.07 mmol/L) levels when compared with those of the cellulose control group. These data suggest that ingestion of W. cocos DF could improve the overall Ca and Mg absorptions of the OVX rats fed a low Ca diet. The potential use of sclerotial DFs as a functional food ingredient for enhancing mineral absorption is also discussed.     

Lipidemic Response of Hamsters to Rice Bran,Uncooked or Processed White and Brown Rice,and Processed Corn Starch

This study was undertaken to evaluate the lipidemic response of rice bran and the possible enhancement of its healthful properties by using raw or processed white or brown rice in place of corn starch. All diets contained 10% total dietary fiber, 15% fat, and 0.5% cholesterol. Weanling male golden Syrian hamsters were fed cellulose control (CC), processed corn starch (PCS), cellulose with processed brown rice (CPBR), rice bran (RB), RB with white rice (RBWR), RB with processed white rice (RBPWR), RB with brown rice (RBBR), and RB with processed brown rice (RBPBR) diets. After three weeks, the PCS diet significantly lowered total plasma cholesterol (TC) compared with the CC, CPBR, RBWR, and RBPBR diets. RB and RBBR diets significantly lowered TC and LDL‐C compared with CPBR diet. All the RB‐containing and PCS diets significantly lowered liver cholesterol and liver lipid content. Processing white rice increased TDF content 240% and insoluble dietary fiber (IDF) 360%, whereas soluble dietary fiber (SDF) decreased by 25%. Uncooked brown rice contained 7 times as much TDF as uncooked white rice. Processing brown rice decreased its TDF, IDF and SDF contents by 12, 6, and 42%, respectively. The data suggest that a possible mechanism for cholesterol‐lowering by rice bran, with or without added raw or processed rice (white or brown), is by decreasing lipid digestibility and increasing neutral sterol excretion, whereas cholesterol‐lowering by processed corn starch is mediated through other mechanisms.     

Effect of Elevated Carbon Dioxide Concentration on Rice Quality: Proximate Composition,Dietary Fibers,and Free Sugars

Little is known regarding the impact of elevated carbon dioxide concentration ([CO₂]) on the chemical composition of rice grains. A field experiment was conducted with open‐top chambers with rice (Oryza sativa L. cv. Ariete) grown at two levels of atmospheric CO₂ (375 and 550 μmol/mol), and their effects were monitored on the proximate composition and carbohydrate contents of the grains. Following exposure to elevated [CO₂], soluble dietary fiber increased by 136, 82, and 77% in brown rice, white rice, and bran, respectively. Increases of a lower magnitude (8%) were observed for insoluble dietary fiber in the bran and brown rice. For all 10 sugars identified, there was a trend for increasing their content. For example, increases of 135% were recorded for glucose in the white rice. In all rice milling fractions, elevated [CO₂] reduced the protein (4–15%) and amylose (6–16%) contents, with no effect on the ash, starch, and gross energy contents. The fat content was increased by elevated [CO₂] in the white rice (23%) and tended to decrease in the bran (9%). It is concluded that besides yield, increased dietary fiber might be another positive effect of high levels of atmospheric CO₂ expected by the middle of the current century.     

Extrusion Conditions Modify Hypocholesterolemic Properties of Wheat Bran Fed to Hamsters

Wheat bran was extruded in a twin‐screw extruder at five specific mechanical energy (SME) levels (0.120, 0.177, 0.234, 0.291, and 0.358 kWh/kg, dwb) and the cholesterol‐lowering effects were compared with those of unprocessed wheat bran when fed to four‐week‐old male golden Syrian hamsters (n = 10/treatment) for three weeks. Diets contained 10% total dietary fiber, 10.3% fat, 3% nitrogen, and 0.4% cholesterol. Plasma total cholesterol and very‐low‐density lipoprotein cholesterol were significantly lower with 0.120 kWh/kg extruded wheat bran diet compared with the unextruded wheat bran control. Total triglycerides were significantly lower with 0.120 and 0.177 kWh/kg wheat bran diets compared with those fed 0.291 and 0.358 kWh/kg extruded wheat bran diets. Cholesterol digestibility, total liver cholesterol, and total liver lipids were significantly lower with all the extruded wheat bran diets compared with the unextruded wheat bran control. Cholesterol digestibility for the 0.291 kWh/kg wheat bran diet was also significantly lower than all other extruded diets. Significantly more sterols were excreted with diets containing 0.291 and 0.358 kWh/kg extruded wheat bran compared with the unextruded wheat bran control. Wheat bran extruded with 0.291 kWh/kg diet resulted in a 13% reduction in plasma cholesterol and a 29% reduction in low‐density lipoprotein cholesterol. Considering lowest cholesterol digestibility, significantly higher sterol excretion, desirable plasma lipo‐protein cholesterol profile, significantly lower liver weight, total liver lipids, and liver cholesterol, the wheat bran extruded at 0.291 kWh/kg appeared to have the most desirable healthful potential. Data suggest that cholesterol‐lowering potential of wheat bran could be enhanced by optimizing the energy input used in the extrusion process.     

Hypolipidemic effect in cholesterol-fed rats of a soluble fiber-rich product obtained from cocoa husks

A new soluble cocoa fiber product (SCFP), obtained after enzymatic treatment of cocoa husks, was characterized and its potential health effects studied in an animal model of dietary-induced hypercholesterolemia. The SCFP was rich in soluble dietary fiber (DF) and antioxidant polyphenols. Consumption of a cholesterol-rich diet containing the SCFP as a source of DF resulted in lower food intake and body weight gain in comparison with control groups consuming cholesterol-free or cholesterol-rich diets with cellulose as DF. The cholesterol-rich diet caused remarkable hypercholesterolemia. However, the SCFP diminished the negative impact of the cholesterol-rich diet, buffering the decrease of high density lipoprotein-cholesterol, and the increase of total and low density lipoprotein-cholesterol levels, and lipid peroxidation (malondialdehyde levels) induced by the fatty diet. The SCFP also decreased triglyceride levels to values lower than those in the group fed the cholesterol-free diet. These results put forward the potential application of the SCFP as a dietary supplement or functional food ingredient.     

Olive oils improve lipid metabolism and increase antioxidant potential in rats fed diets containing cholesterol

The effect of olive oils on lipid metabolism and antioxidant activity was investigated on 60 male Wistar rats adapted to cholesterol-free or 1% cholesterol diets. The rats were divided into six diet groups of 10. The control group (control) consumed the basal diet (BD) only, which contained wheat starch, casein, cellulose, and mineral and vitamin mixtures. To the BD were added 10 g/100 g virgin (virg group) or Lampante (Lamp group) oils, 1 g/100 g cholesterol (chol group), or both (chol/virg group) and (chol/Lamp group). The experiment lasted 4 weeks. Plasma total cholesterol (TC), LDL-cholesterol (LDL-C), HDL-cholesterol (HDL-C), triglycerides (TG), total phospholipids (TPH), HDL-phospholipids (HDL-PH), total radical-trapping antioxidative potential (TRAP), malondialdehyde lipid peroxidation (MDA), and liver TC were measured. Groups did not differ before the experiment. In the chol/virg and chol/Lamp vs chol group, the oil-supplemented diets significantly (P < 0.05) lessened the increase in plasma lipids due to dietary cholesterol as follows: TC (25.1 and 23.6%), LDL-C (39.3 and 34.7%), TG (19.3 and 17.0%), and TC in liver (36.0 and 35.1%) for the chol/virg and chol/Lamp group, respectively. The chol/virg and chol/Lamp diets significantly decreased the levels of TPH (24.7 and 21.2%; p < 0.05 in both cases) and HDL-PH (22.9 and 18.0%; p < 0.05 in both cases) for the chol/virg and chol/Lamp group, respectively. Virgin and Lampante oils in rats fed basal diet without cholesterol did not affect the lipid variables measured. Virgin, and to a lesser degree Lampante, oils have increased the plasma antioxidant activity in rats fed BD without cholesterol (an increase in TRAP, 20.6 and 18.5%; and a decrease in MDA, 23.2 and 11.3%, respectively). In the rats of chol/virg and chol/Lamp vs Chol diet groups the added oils significantly hindered the decrease in the plasma antioxidant activity (TRAP, 21.2 and 16.7%; and MDA, 27.0 and 22.3%, respectively). These results demonstrate that virgin, and to less degree Lampante, oils possess hypolipidemic and antioxidant properties. It is more evident when these oils are added to the diets of rats fed cholesterol. These positive properties are attributed mostly to the phenolic compounds of the studied oils.     

Effect of Wheat Bran Fiber and Bran Particle Size on Fat and Fiber Digestibility and Gastrointestinal Tract Measurements in the Rat

The effect of wheat bran (AACC hard red) and bran particle size on fat and fiber digestibility and gastrointestinal tract measurements were investigated with diets containing 5.7–10.7% dietary fiber. Fifty‐six male weanling Sprague‐Dawley rats were randomly assigned to four diets containing 5% cellulose (C5); 10.5% cellulose (C10); 21.5% coarse (2 mm) wheat bran (CB); or 22.2% fine (0.5 mm) wheat bran (FB) in a sixweek study. Dietary fiber digestibilities were significantly different (P < 0.05) among treatment diets (CB > FB > C5 > C10) but there was no effect in fat digestibility among treatments. High‐fiber diets fed to rats resulted in significantly greater wet and dry fecal weights than low‐fiber diets. Bran diets resulted in significantly higher fecal moisture than cellulose diets. Cecum lengths increased significantly with bran diets compared with cellulose diets. The CB diet resulted in significantly higher stomach weights than with cellulose diets. Stomachs were heavier and cecal lengths were greater with bran diets than with cellulose diets; however, a high‐cellulose diet resulted in increased colon weight. Except for higher fiber digestibility of coarse bran, bran particle size had no significant effects. Healthful effects of wheat bran may be associated with gastrointestinal morphology and function. Fecal bulking and decreased intestinal transit time can prevent constipation and may dilute or reduce absorption of toxic or carcinogenic metabolites, thus improving gastrointestinal health and lowering the risk of tumor development and cancer.     

Formation of phenolic microbial metabolites and short-chain Fatty acids from rye, wheat, and oat bran and their fractions in the metabolical in vitro colon model

Rye bran and aleurone, wheat bran and aleurone, and oat bran and cell wall concentrate were compared in their in vitro gut fermentation patterns of individual phenolic acids and short-chain fatty acids, preceded by enzymatic in vitro digestion mimicking small intestinal events. The formation of phenolic metabolites was the most pronounced from the wheat aleurone fraction. Phenylpropionic acids, presumably derived from ferulic acid (FA), were the major phenyl metabolites formed from all bran preparations. The processed rye, wheat, and oat bran fractions contained more water-extractable dietary fiber (DF) and had smaller particle sizes and were thus more easily fermentable than the corresponding brans. Rye aleurone and bran had the highest fermentation rate and extent probably due to high fructan and water-extractable arabinoxylan content. Oat samples also had a high content of water-extractable DF, β-glucan, but their fermentation rate was lower. Enzymatic digestion prior to in vitro colon fermentation changed the structure of oat cell walls as visualized by microscopy and increased the particle size, which is suggested to have retarded the fermentability of oat samples. Wheat bran was the most slowly fermentable among the studied samples, presumably due to the high proportion of water-unextractable DF. The in vitro digestion reduced the fructan content of wheat samples, thus also decreasing their fermentability. Among the studied short-chain fatty acids, acetate dominated the profiles. The highest and lowest production of propionate was from the oat and wheat samples, respectively. Interestingly, wheat aleurone generated similar amounts of butyrate as the rye fractions even without rapid gas production.     

Inulin effects on bioavailability of soy isoflavones and their calcium absorption enhancing ability

The effect of inulin on isoflavone absorption and the effect of isoflavones and synergy with inulin on calcium absorption in rats was investigated. Rats (n = 48) were divided into three groups and fed inulin (50 mg/g), isoflavone (8 mg/g) or inulin + isoflavone (50 mg/g + 8 mg/g) diets for 21 days. After a 2-h fast, rats were given (45)Ca orally or intraperitoneally, together with 25 mg of calcium as calcium acetate. Blood and femurs were collected 4 days later. Sera were analyzed for isoflavones using HPLC-MS, femurs for (45)Ca by beta-scintillation counting, and total femoral calcium by atomic absorption spectroscopy. Both groups fed isoflavones had similar and significantly higher weight-adjusted total femoral calcium content compared to the inulin-fed group (p < 0.0001). (45)Ca absorption was significantly higher (p < 0.01) when isoflavones were added to the diet, and serum equol was significantly lower (p < 0.01) when inulin was added to the diet containing isoflavones. We conclude that isoflavones enhance calcium absorption, without synergy from inulin, and that inulin decreases equol production.     

Nutritional effects of enzymatically modified soybean oil with caprylic acid versus physical mixture analogue in obese Zucker rats

Enzymatically modified soybean oil with caprylic acid (SL), a physical mixture of tricaprylin and soybean oil (PHY), and soybean oil as control were fed (20% of diet weight) to female obese Zucker rats. Both lipids (SL and PHY) have similar total fatty acid composition containing 23.4 mol % caprylic acid (C8:0) but have different lipid structures. After 21 days of feeding, the body weight gain was 36.4% in the SL-fed group and 35.2% in the PHY-fed group, respectively; whereas the body weight of the control group increased 41.6%. Significant differences in the respiratory exchange ratio were observed between the SL and PHY groups. However, the contents of glucose, total and high density lipoprotein (HDL) cholesterol, and very low density and low density lipoprotein (VLDL + LDL) cholesterol in serum were not significantly different between the SL- and PHY-fed groups or among the three dietary groups (control, SL, and PHY) (p < 0.05). On the other hand, plasma total cholesterol and plasma triacylglycerol (TAG) were significantly higher in SL- and PHY-fed groups than in the control group. In the liver and inguinal adipocyte TAG, C8:0 was found in the SL-fed group, whereas it was not observed in the liver and inguinal adipocyte TAG of the PHY-fed group, which suggests that positional distribution of C8:0 of the TAG molecule is an important consideration in the metabolism of lipids. This study showed that different positional distribution in TAG molecules lead to different metabolic fates, resulting in the change of fatty acid composition in liver and inguinal adipose TAG in female Zucker rats.     

Effect of a proanthocyanidin-rich extract from longan flower on markers of metabolic syndrome in fructose-fed rats

Recent evidence strongly suggests that oxidative stress due to redox imbalance is highly associated with metabolic syndrome. The objective of this study was to evaluate the effect of the supplementation of longan flower water extract (LFWE), which showed powerful antioxidative activity in vitro, on markers of metabolic syndrome in a fructose-fed rat model. Male Sprague-Dawley rats were randomly divided into four groups: group C, fed with standard Purina chow; group F, fed with high-fructose diet (HF) alone; group L, fed with HF plus LFWE 125 mg/kg bw per day by gavage; and group H, fed HF plus LFWE 250 mg/kg bw per day by gavage. The dietary manipulation lasted for 14 weeks. Results of our study showed that rats fed with HF resulted in oxidative stress and affected the antioxidant status including plasma thiobarbituric acid and liver antioxidant enzyme activity. Treatment with LFWE significantly augmented the antioxidant system. HF was able to cause insulin resistance and elevation of the blood pressure. The supplementation of LFWE ameliorated insulin resistance by enhancing the expression of insulin signaling pathway related proteins, including insulin receptor substrate-1 and glucose transporter 4. LFWE supplementation was also found to decrease systolic blood pressure. These findings indicate that longan flower water extract may improve the symptoms of metabolic syndrome in fructose-fed rats.     

Relationship Between Hydrolytic Rancidity,Oil Concentration,and Esterase Activity in Rice Bran

Hydrolytic rancidity restricts the utilization of rice bran, reducing its potential value. In the present study, three groups of eight rice cultivars each displaying different levels of oil concentration (high, medium, and low) were cultivated in 1999 and 2000 under field conditions and evaluated for oil content, hydrolytic rancidity, and esterase activity in the bran fraction. Genotype effects were statistically significant for all measured traits (P < 0.05), whereas environment (year) was nonsignificant. Hydrolytic rancidity was strongly correlated with esterase activity (r = 0.89***), but not with oil concentration (r = ‐0.01). A wide variation was found for both hydrolytic rancidity and esterase activity, which ranged from 6.8 to 56.0 mg of C8:0/g of bran (CV = 49.1%) and from 4.3 to 22.8 mg of C8:0/g of bran (CV = 34.3%), respectively. Red bran displayed the lowest values for both hydrolytic rancidity (mean = 10.2 mg of C8:0/g of bran) and esterase activity (mean = 5.4 mg of C8:0/g of bran). Apparently, the low values for hydrolytic rancidity were related to the inhibition effect of bran tannins on lipase activity. In conclusion, cultivar variation was detected for both hydrolytic rancidity and esterase activity in the studied genotypes, esterase activity being the principal factor explaining the variation found for the former trait. Therefore, it may be possible to create new cultivars with increased stability against hydrolytic rancidity by selecting for lower esterase activity.     

Reaction of fumonisin with glucose prevents promotion of hepatocarcinogenesis in female F344/N rats while maintaining normal hepatic sphinganine/sphingosine ratios

The reaction of the primary amine of fumonisin B(1) (FB(1)) with glucose was hypothesized to detoxify this mycotoxin. Eighty 10-day-old female F344/N rats were injected intraperitoneally with diethylnitrosamine (DEN; 15 mg/kg of body weight). At 4 weeks of age, the weaned rats were randomly assigned to one of four treatment groups with 20 rats each. At 9 weeks of age, four rats from each treatment group were killed. At 12 weeks, another five rats from each group were killed. At 20 weeks of age, the remaining rats were killed. In comparison with the rats fed basal diet or FB(1)-glucose (containing 25 ppm of FB(1)), rats fed 8 ppm (residual amount of free FB(1) in the FB(1)-glucose mixture) or 25 ppm of FB(1) had greater alanine aminotransferase activity at 9 and 20 weeks of age (P < 0.001), greater endogenous hepatic prostaglandin E(2) production at 20 weeks of age (P < 0.05), and significantly lower plasma cholesterol at 20 weeks of age (P < 0.01). Placental glutathione S-transferase (PGST)-positive and gamma-glutamyltransferase (GGT)-positive altered hepatic foci (AHF) occurred only in rats fed 25 ppm of FB(1) at 20 weeks of age. Hepatic natural killer (NK) cell activities were similar among the four groups, but the percentage of total liver-associated mononuclear cells exhibiting the NKR-P1(bright) marker was significantly greater in rats fed FB(1)-glucose, FB(1) (8 ppm) and FB(1) (25 ppm) than in control rats at 9 weeks of age, and FB(1)-glucose-treated rats had significantly lower NKR-P1(bright) cells as a percentage of total liver-associated mononuclear cells than rats fed 25 ppm of FB(1) at 20 weeks of age (P < 0.05). PGST- or GGT-positive AHF were not detected in any treatment group at 9 or 12 weeks of age. At 20 weeks of age, half of the rats fed 25 ppm of FB(1) had PGST- and GGT-positive AHF. The sphinganine (Sa) concentration and the Sa/sphingosine (So) ratio were significantly greater in the rats fed 25 ppm of FB(1) diet as compared with the control groups at, respectively, 12 or 20 weeks of age. Therefore, modifying FB(1) with glucose seems to prevent FB(1)-induced hepatotoxicity and promotion of hepatocarcinogenesis. The Sa/So ratio was not the most sensitive biomarker of FB(1) toxicity.     

Ingestion of water-soluble soybean fiber prevents osteopenia and hypercholesterolemia induced by ovariectomy in rats

This study examined the effects of feeding water-soluble soybean fiber (WSSF), a highly fermentable dietary fiber with low viscosity, on intestinal calcium (Ca) absorption, bone mineral content, and serum total cholesterol levels using female Sprague-Dawley rats (5 weeks old) with or without ovariectomy (OVX). The rats in each group were fed a WSSF (50 g/kg of diet) or WSSF-free diet for 4 weeks. Ca absorption was higher in OVX rats fed the WSSF diet than in OVX rats fed the WSSF-free diet. Femoral Ca content in both sham and OVX rats fed the WSSF diet was higher than that in rats fed the WSSF-free diet. The serum total cholesterol levels were elevated after OVX compared with that in the sham rats, and this elevation was prevented by the WSSF diet. In conclusion, ingestion of WSSF prevented osteopenia and hypercholesterolemia induced by ovariectomy in rats.