No abstract

Native wheat, oat, potato and lentil starches were annealed at various starch/water ratios at 50C for time intervals ranging from 0.5 to 72 h. Annealing did not change granule size and shape. Oat starch granules were less compactly packed after annealing. X‐ray diffraction patterns remained unchanged and X‐ray intensities changed only marginally in all starches. The swelling factor (SF), amylose leaching (AML) and the gelatinization temperature range (GTR) decreased on annealing. The extent of decrease in SF and AML followed the order: lentil > wheat > potato > oat, while the corresponding order for GTR was: wheat > lentil > oat > potato. The gelatinization transition temperatures (GTT) and enthalpy (ΔH) increased on annealing. However, the increases in GTT and ΔH did not begin concurrently during the time course of annealing. Increases in ΔH were slower and were evident only after 1, 2, 6 and 48 h, respectively, in lentil, potato, oat and wheat starches. The extent and rate of increase in GTT and ΔH followed the order: potato > lentil > wheat > oat. The magnitude of changes in GTT and ΔH increased with increase in annealing moisture content. The susceptibility of oat starch to enzyme and acid hydrolysis increased on annealing. However, decreases occurred in the other starches (lentil > wheat > potato). Thermal and shear stability of starch granules increased on annealing (potato > lentil > wheat > oat). The results showed that the above changes in physicochemical properties were due to increased interaction between starch components during annealing.

No abstract

No abstract

No abstract

No abstract

Phenolic acids from 30 barley varieties (combination of hulled/hulless/two-row/six-row/regular/waxy) were investigated by HPLC following four different sample treatments: (a) simple hot water extraction, (b) extraction after acid hydrolysis, (c) acid plus alpha-amylase hydrolysis, and (d) acid plus alpha-amylase plus cellulase hydrolysis treatments. The benzoic acid (p-hydroxybenzoic, vanillic, and protocatechuic acids) and cinnamic acid derivatives (coumaric, caffeic, ferulic, and chlorogenic acids) were identified, and some of the phenolic acids were quantified after each above-mentioned treatment. The data indicated that a combination of sequential acid, alpha-amylase, and cellulase hydrolysis treatments might be applicable for release of more phenolic acids from barley.

BBn (BioBreeding) rats were fed casein-based diets supplemented with barley flour, oatmeal flour, cellulose, or barley ␤-glucans of high [HV] or low viscosity [LV] in order to measure the prebiotic effects of these different sources of dietary fiber. The dietary impact on the composition of the cecal microbiota was determined by the generation of denaturing gradient gel electrophoresis (DGGE) profiles of PCR-amplified 16S rRNA gene sequences. The DGGE profiles produced from the cecal microbiota of rats within each dietary group were similar, but consensus profiles generated from pooled bacterial DNAs showed differences between rat groups. Animals fed HV glucans (HV-fed rats) had DGGE consensus profiles that were 30% dissimilar from those of the other rat groups. A 16S rRNA gene fragment that was more conspicuous in the profiles of HV-fed animals than in those of cellulose-fed rats had sequence identity with Lactobacillus acidophilus. Measurements of L. acidophilus rRNA abundance (DNA-RNA hybridization), the preparation of cloned 16S rRNA gene libraries, and the enumeration of Lactobacillus cells (fluorescent in situ hybridization) showed that lactobacilli formed a greater proportion of the cecal microbiota in HV-fed rats. In vitro experiments confirmed that some lactobacilli utilize oligosaccharides (degree of polymerization, 3 or 4) present in ␤-glucan hydrolysates. The results of this study have relevance to the use of purified ␤-glucan products as dietary supplements for human consumption.