Phase behaviour of casein micelles and barley beta-glucan polymer molecules in dietary fibre-enriched dairy systems.

Enrichment of colloidal dairy systems with dietary fibre frequently causes quality defects because of phase separation. We investigate phase separation in skimmed milk enriched with Glucagel (a commercial product made from barley that is predominantly comprised of the polysaccharide ß-glucan). The driving force for phase separation was depletion flocculation of casein micelles in the presence of molecules of the polysaccharide. Depending on the volume fraction of casein micelles and the concentration of Glucagel, the stable system phase separated either as a transient gel or as a sedimented system. The rate at which phase separation progressed also depended on the volume fraction of casein micelles and the concentration of Glucagel. To confirm the role of depletion flocculation in the phase separation process, enzymatic reduction in the molecular weight of ß-glucan was shown to limit the range of attraction between micelles and allow the stable phase to exist at a higher ß-glucan concentration for any given volume fraction of casein micelles. These phase diagrams will be useful to dairy product manufacturers striving to improve the nutrient profile of their products while avoiding product quality impairment.

Inhibition of microbial growth and enrichment of gamma-aminobutyric acid during germination of brown rice by electrolyzed oxidizing water.

Electrolyzed oxidizing water (EOW) has been regarded as a potential environmentally friendly broad spectrum microbial decontaminant. EOW with a pH of 3.0 and oxidation reduction potential of 1,079.0 mV were generated by the electrolysis of a dilute NaCl solution (20 mM) in an electrochemical cell. The effects of EOW, 1% NaClO solution, and alkaline electrolyzed water on controlling microbial growth, germination ratio, and enrichment of gamma-aminobutyric acid in germinated brown rice (GBR) were evaluated in this study. Results show that EOW was the most effective at inhibiting microbial growth during germination. Rinsing the rice grains with EOW at 12-h intervals resulted in aerobic plate count reductions of 4.82 log CFU/g, while soaking resulted in bacterial count reductions of 5.38 log CFU/g after 72 h of germination. Moreover, EOW significantly enriched gamma-aminobutyric acid content in GBR (P < 0.05); content was increased 1.6 times in grain rinsed with EOW and 1.8 times in grain soaked in EOW. The findings indicate that EOW is a feasible disinfectant for industrial GBR production.

Physiological effects of concentrated barley beta-glucan in mildly hypercholesterolemic adults.

OBJECTIVE: Barley fiber rich in beta-glucans lowers serum lipids, but is difficult to incorporate into products acceptable to consumers. We investigated the physiological effects of two concentrated barley beta-glucans on cardiovascular disease (CVD) endpoints and body weight in human subjects. METHODS: Hypercholesterolemic men and women (n = 90) were randomly assigned to one of two treatments: low molecular weight (low-MW) or high molecular weight (high-MW) concentrated barley beta-glucan consumed as a daily supplement containing 6 grams beta-glucan/day. Fasting blood samples were collected at baseline and week 6 and analyzed for total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides, glucose, insulin, homocysteine and C-reactive protein (CRP). Dietary intakes, body weights, blood pressure, hunger ratings, and gastrointestinal symptoms were measured at baseline and 6 weeks. RESULTS: The only difference between treatments in lipid outcomes at week 6 was a reduction of the cholesterol/HDL ratio in the low-MW group and a small increase in the high-MW group. No changes were found in blood pressure, glucose, insulin, and gastrointestinal symptoms. Body weight decreased from baseline to 6 weeks in the high-MW group while body weight increased in the low-MW group. Levels of hunger decreased slightly in the low-MW group and decreased significantly in the high-MW group (P = 0.02) CONCLUSION: Overall, supplementation with isolated barley beta-glucans of different molecular weights had small effects on cardiovascular disease markers. Molecular weight of the barley fiber did alter effects on body weight with the high-MW fiber significantly decreasing body weight.

Light filtering by epidermal flavonoids during the resistant response of cotton to Xanthomonas protects leaf tissue from light-dependent phytoalexin toxicity.

2,7-Dihydroxycadalene and lacinilene C, sesquiterpenoid phytoalexins that accumulate at infection sites during the hypersensitive resistant response of cotton foliage to Xanthomonas campestris pv. malvacearum, have light-dependent toxicity toward host cells, as well as toward the bacterial pathogen. Adaxial epidermal cells surrounding and sometimes covering infection sites turn red. The red cells exhibited 3-4-fold higher absorption at the photoactivating wavelengths of sunlight than nearby colorless epidermal cells. Red epidermal cells protected underlying palisade mesophyll cells from the toxic effects of 2,7-dihydroxycadalene plus sunlight, indicating a role for epidermal pigments in protecting living cells that surround infection sites from toxic effects of the plant's own phytoalexins. A semi-quantitative survey of UV-absorbing substances extracted from epidermal strips from inoculated and mock-inoculated cotyledons indicated that the principal increase in capacity to absorb the photoactivating wavelengths was due to a red anthocyanin and a yellow flavonol, which were identified as cyanidin-3-O-beta-glucoside and quercetin-3-O-beta-glucoside, respectively.

Influence of added bean flour (Phaseolus vulgaris L.) on some physical and nutritional properties of wheat flour tortillas.

Composite flours containing 15%, 25%, or 35% of small red, black, pinto, or navy bean flours (BF) and wheat were made into tortillas. Dough rheology, firmness, cohesiveness, rollability, and some physical properties of tortillas were negatively affected as BF concentration increased regardless of bean cultivar. Nutritionally, all bean tortillas had significantly higher levels of crude protein, total phenols, 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS(+)) in vitro antioxidant activity (AA) and antinutritional compounds such as phytic acid (PA) and trypsin inhibitors (TI) than the wheat control. Tortillas to which 35% of small red, pinto and black BF was added had the highest levels of phenols, which were significantly correlated with both DPPH (r=0.99) and ABTS(+) (r=0.99) AA. Compared to raw flours, PA and TI were reduced from 37.37% to 43.78% and from 50% to 66%, respectively, in the tortillas. Overall analysis indicated that tortillas with acceptable texture and improved nutritional profile were produced at 25% substitution.

Concentrated oat beta-glucan, a fermentable fiber, lowers serum cholesterol in hypercholesterolemic adults in a randomized controlled trial.

BACKGROUND: Soluble fibers lower serum lipids, but are difficult to incorporate into products acceptable to consumers. We investigated the physiological effects of a concentrated oat beta-glucan on cardiovascular disease (CVD) endpoints in human subjects. We also compared the fermentability of concentrated oat beta-glucan with inulin and guar gum in a model intestinal fermentation system. METHODS: Seventy-five hypercholesterolemic men and women were randomly assigned to one of two treatments: 6 grams/day concentrated oat beta-glucan or 6 grams/day dextrose (control). Fasting blood samples were collected at baseline, week 3, and week 6 and analyzed for total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides, glucose, insulin, homocysteine and C-reactive protein (CRP). To estimate colonic fermentability, 0.5 g concentrated oat beta-glucan was incubated in a batch model intestinal fermentation system, using human fecal inoculum to provide representative microflora. Fecal donors were not involved with the beta-glucan feeding trial. Inulin and guar gum were also incubated in separate serum bottles for comparison. RESULTS: Oat beta-glucan produced significant reduction from baseline in total cholesterol (-0.3 +/- 0.1 mmol/L) and LDL cholesterol (-0.3 +/- 0.1 mmol/L), and the reduction in LDL cholesterol were significantly greater than in the control group (p = 0.03). Concentrated oat beta-glucan was a fermentable fiber and produced total SCFA and acetate concentrations similar to inulin and guar gum. Concentrated oat beta-glucan produced the highest concentrations of butyrate at 4, 8, and 12 hours. CONCLUSION: Six grams concentrated oat beta-glucan per day for six weeks significantly reduced total and LDL cholesterol in subjects with elevated cholesterol, and the LDL cholesterol reduction was greater than the change in the control group. Based on a model intestinal fermentation, this oat beta-glucan was fermentable, producing higher amounts of butyrate than other fibers. Thus, a practical dose of beta-glucan can significantly lower serum lipids in a high-risk population and may improve colon health.

[Comparative studies of oat cultivars from Southern Brazil: effect of grain morphology on industrial yield]. / Estudo comparativo de cultivares de aveia (Avena sativa L.) do sul do Brasil: efeito da morfologia do grão no rendimento industrial.

The purpose of this work was to study the effect of grain morphology of oats on their industrial yield. The five cultivars studied: CTC3, UFRGS7, UFRGS14, UPF7 and UPF16 were grown in three localities with different soil and climate conditions, for two consecutive years. The parameters evaluated in the oat samples before and after dehulling were grain size and shape (by image analysis), comparing them to industrial yield, weight of a thousand kernels and hectoliter weight. The results showed that image analysis of oat samples (with hulls), does not have any relation to industrial yield, different from what was observed with groat samples (dehulled). Industrial yield varied according to genotype, locality and year, while area, minimum and maximum diameters and grain shape were only affected by the genetic factor. It was observed that longer grains (UPF16) had the highest industrial yield, differently to rounder and shorter grains (UFRGS14) which had a lower yield due to the ease of breakage during hulling; the smallest grains also gave a low industrial yield.

Estudo comparativo de cultivares de aveia (Avena sativa L. ) do sul do Brasil: efeito da morfologia do grão no rendimento industrial / Comparative studies of oat cultivars from Southern Brazil: effect of grain morphology on industrial yield

The purpose of this work was to study the effect of grain morphology of oats on their industrial yield. The five cultivars studied: CTC3, UFRGS7, UFRGS14, UPF7 and UPF16 were grown in three localities with different soil and climate conditions, for two consecutive years. The parameters evaluated in the oat samples before and after dehulling were grain size and shape (by image analysis), comparing them to industrial yield, weight of a thousand kernels and hectoliter weight. The results showed that image analysis of oat samples (with hulls), does not have any relation to industrial yield, different from what was observed with groat samples (dehulled). Industrial yield varied according to genotype, locality and year, while area, minimum and maximum diameters and grain shape were only affected by the genetic factor. It was observed that longer grains (UPF16) had the highest industrial yield, differently to rounder and shorter grains (UFRGS14) which had a lower yield due to the ease of breakage during hulling; the smallest grains also gave a low industrial yield