Effect of radiation on chemical composition and protein quality of cottonseed meal.

This study was conducted to compare the effects of electron beam (EB) and gamma ray (GR) irradiation treatments at doses of 10, 20 and 30 kGy on chemical composition, protein quality and protein digestibility of cottonseed meal (CSM). GR irradiation in all doses significantly decreased the crude fiber of samples compared to raw CSM. Free and total gossypol content of CSM was decreased significantly by utilizing both types of irradiation in a dose-dependent manner. Also, EB irradiation caused decrease in free and total gossypol content more than that of GR irradiation. GR irradiation at doses of 20 and 30 kGy, and EB irradiation at doses of 10, 20 and 30 kGy can significantly decrease protein solubility of CSM compared to that of a raw sample. GR irradiation at a dose of 30 kGy significantly increased apparent digestibility of protein compared to raw and EB irradiation of CSM at a dose of 10 kGy in Leghorn cockerels. Maximum increase in protein digestibility of CSM was observed in GR irradiation at a dose of 30 kGy. In conclusion, the present study showed that EB and GR irradiation reduced gossypol and crude fiber and increased protein digestibility of CSM but had no effect on protein quality of CSM.

Production of xylooligosaccharide from wheat bran by microwave assisted enzymatic hydrolysis.

The effective production of xylooligosaccharides (XOS) from wheat bran was investigated. Wheat bran contains rich hemicellulose which can be hydrolyzed by enzyme; the XOS were obtained by microwave assisted enzymatic hydrolysis. To improve the productivity of XOS, repeated microwave assisted enzymatic hydrolysis and activated carbon adsorption method was chosen to eliminate macromolecules in the XOS. On the basis of experimental data, an industrial XOS production process consisting of pretreatment, repeated microwave assisted enzymatic treatment and purification was designed. Using the designed process, 3.2g dry of purified XOS was produced from 50 g dry wheat bran powder.

Microwave-assisted extraction of bound phenolic acids in bran and flour fractions from sorghum and maize cultivars varying in hardness.

To release bound phenolic acids, a microwave-assisted extraction procedure was applied to bran and flour fractions obtained from eight sorghum and eight maize cultivars varying in hardness. The procedure was followed by HPLC analysis, and the identities of phenolic acids were confirmed by MS/MS spectra. The extraction of sorghum and maize bound phenolic acids was done for 90 s in 2 M NaOH to release ferulic acid and p-coumaric acid from bran and flour. Two diferulic acids, 8-O-4'- and 8-5'-benzofuran form, were identified and quantitated in sorghum bran, and only the former was found in maize bran. The contents of ferulic acid and diferulic acids in sorghum bran were 416-827 and 25-179 µg/g, respectively, compared to 2193-4779 and 271-819 µg/g in maize. Phenolic acid levels of sorghum were similar between hard and soft cultivars, whereas those of maize differed significantly (p < 0.05) except for ferulic acid in flour. Sorghum phenolic acids were not correlated with grain hardness as measured using a tangential abrasive decortication device. Maize ferulic acid (r = -0.601, p < 0.01), p-coumaric acid (r = -0.668, p < 0.01), and 8-O-4'-diferulic acid (r = -0.629, p < 0.01) were significantly correlated with hardness.

Intestinal degradation of dietary fibre in green beans--effects of microwave treatments.

Intestinal degradation of dietary fibre in blanched and microwaved green beans was studied by using a rat experimental model. Content and composition of dietary fibre as well as molecular weight distribution of water-soluble polysaccharides (WSP) were analysed. There was a solubilization and a shift towards lower Mw of mainly uronic acid-containing polysaccharides with repeated microwave treatment in the raw material. Thus, the apparent Mw of water-soluble polysaccharides decreased from approximately 1,550,000 to approximately 300,000. After the beans had been digested the Mw of the WSP was significantly reduced, to approximately 100,000, and the differences in Mw seen between various processed raw materials had been evened out. After fermentation the Mw of the WSP decreased further approximately 10 times. Fibre fermentability was high (approximately 90%) and similar for the various processed beans.

Heat or gamma irradiation sterilization affects the hypocholesterolemic effect of guar gum in axenic and heteroxenic rats.

1. Twenty-two axenic (germfree) or thirty heteroxenic (axenic colonized with human flora) 2.5-3.5 months old female Fisher rats were fed for four weeks either a hypercholesterolemic (HYPER) diet or a HYPER diet containing 5% guar gum (GG) sterilized by heat or by gamma irradiation. 2. Axenic rats fed the irradiated GG diet had higher cholesterolemia than their counterparts fed an autoclaved diet (4.50 vs 2.29 mmol/l), whereas the method of sterilization had no effect on plasma cholesterol in axenic HYPER or heteroxenic animals (7.35 vs 6.51 mg/dl). 3. The levels of hepatic esterified cholesterol were higher in heteroxenic animals fed the irradiated GG diet than in their counterparts fed the autoclaved GG diet (5.65 vs 3.57 mmol/g tissue). 4. The composition of volatile fatty acids in the cecal content of heteroxenic rats was dependent on the method of sterilization regardless of the presence of fiber: the levels of butyrate were 2.88 and 0.85 mumol/g for rats fed the autoclaved and irradiated diets, respectively. 5. Gamma irradiation abolished the cholesterol-lowering effect of guar gum, whereas sterilization by heat preserved this effect. 6. The hypocholesterolemic effect of guar was reduced by gamma irradiation sterilization and was probably mediated by qualitative changes in the intestinal microflora which interfered with bile acid absorption.

Heat or gamma irradiation sterilization affects the hypocholesterolemic effect of guar gum in axenic and heteroxenic rats

1. Twenty-two axenic (germfree) or thirty heteroxenic (axenic colonized with human flora) 2.5-3.5 months old female Fisher rats were fed for four weeks either a hypercholesterolemic (HYPER) diet or a HYPER diet containing 5 per cent guar gum (GG) sterilized by heat or by gamma irradiation. 2. Axenic rats fed the irradiated GG diet had higher cholesterolemia than their counterparts fed an autoclaved diet (4.50 vs 2.29 mmol/l), whereas the method of sterilization had no effect on plasma cholesterol in axenic HYPER or heteroxenic animals (7.35 vs 6.51 mg/dl). 3. The levels of hepatic esterified cholesterol were higher in heteroxenic animals fed the irradiated GG diet than in their counterparts fed the autoclaved GG diet (5.65 vs 3.57 mmol/g tissue). 4. The composition of volatile fatty acids in the cecal content of heteroxenic rats was dependent on the method of sterilization regardless of the presence of fiber: the levels of butyrate were 2.88 and 0.85 mumol/g for rats fed the autoclaved and irradiated diets, respectively. 5. Gamma irradiation abolished the cholesterol-lowering effect of guar gum, whereas sterilization by heat preserved this effect. 6. The hypocholesterolemic effect of guar was reduced by gamma irradiation sterilization and was probably mediated by qualitative changes in the intestinal microflora which interfered with bile acid absorption