Physicochemical and structural characteristics of water-extractable arabinoxylan from rye lines varying in extract viscosity and its relationship to end-use characteristics

Five rye (Secale cereale L.) lines ranging in extract viscosity (EV) from 5 to 95 cp were evaluated with respect to their physiochemical characteristics and those of their constituent water-extractable arabinoxylans (WEAXs). A significant positive correlation was observed between the EVs of rye wholemeals and their soluble dietary fibre and WEAX contents. Gel permeation chromatography of rye wholemeal water extracts revealed the presence of different proportions of a high molecular weight fraction (HAM), which correlated positively with their EVs. Treatment of a water extract of rye with xylanase followed by gel permeation chromatography indicated that the FDAW consisted primarily of arabinoxylan. Successive treatment of a water extract of rye with α-amylase, lichenase, protease and xylanase confirmed that the viscosity of the extract was primarily related to its content of arabinoxylan. Microscopic examination revealed that kernels of high EV rye had somewhat larger aleurone cells and thicker endosperm cell walls than did kernels of low EV rye. Extract viscosities of rye flours were higher than those of corresponding wholemeals, indicating concentration of WEAX in flour. Failing numbers of flours in the presence or absence of enzyme inhibitor correlated positively with their EVs. Farinography and breadmaking tests revealed that EV of rye flours and rye/wheat flour blends was positively correlated with dough stability and negatively correlated with loaf volume. Inclusion of rye, particularly high EV rye, in chick diets seriously impeded growth performance and feed efficiency. Substantially lower digesta viscosities were observed in chicks fed bread diets than in those fed wholemeals. Water-extractable arabinoxylan was isolated from high, intermediate and low EV ryes. Structural analysis using H-NMR indicated that the WEAX from high EV rye was a less branched macromolecule having a lower degree of di-substituted Xy1p residues and a higher degree of un-substituted Xy1p residues as compared to WEAXs from intermediate and low EV ryes. Size exclusion HPLC/triple detection revealed that the WEAX from high EV rye had a higher molecular weight, a larger radius of gyration, a larger hydrodynamic radius and a higher intrinsic viscosity compared to the WEAXs from intermediate and low EV ryes

Nutrient content and viscosity of Saskatchewan grown pulses in relation to their cooking quality

Pulses are staple foods that are gaining recognition as sources of non-gluten proteins, slowly-digestible starch and dietary fiber. Several factors contribute to the cooking quality of pulses including genetics, environmental and their interactions. In this study, four cultivars each of faba bean, lentil and pea were evaluated for nutrient content, flour viscosity measured by rapid visco analyzer (RVA), and acid and alkaline extract viscosity determined by cone-plate viscometer. These properties were analyzed in relation to seed hydration and firmness of cooked pulses measured by texture analyzer to better understand their relationships with and contribution to pulse cooking quality. Pea had the lowest protein (18.7-22.3%) and highest starch (43.0-46.3%) followed by lentil (protein 25.1-26.7%, starch 38.4-45.5%), and finally faba bean (protein 26.5-29.2%, starch 38.4-41.8%). Significant differences (pThe accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Composition of Phenolic Acids and Antioxidant Properties of Selected Pulses Cooked with Different Heating Conditions

Pulses are recommended for healthy eating due to their high content of nutrients and bioactive compounds that can undergo changes during cooking. This study investigated the effects of four cooking methods (boiling, pressure, microwave, slow) and three heating solutions (water, salt, sugar) on the phenolic acids and antioxidant properties of three pulses (faba beans, lentils, peas). The composition of phenolic acids differed among the three pulses with p-coumaric and ferulic being the dominant acids. Cooking increased free phenolic acids and lessened bound phenolic acids in faba beans and peas, while decreased both free and bound phenolic acids in lentils. Cooking resulted in reductions in total phenol content (TPC) in faba bean methanol and bound extracts. Pressure and microwave cooking increased TPC in lentil methanol extracts, while pot boiling and slow cooking reduced TPC. Microwave cooking resulted in increases in TPC in bound phenolic extracts from lentils. For peas, cooking increased TPC in both methanol and bound phenolic extracts. Significant changes were also observed in the antioxidant capacity of cooked pulses based on the scavenging ability of DPPH, ABTS and peroxyl radicals subject to the type of pulse, polyphenol and antioxidant assay. Despite the significant reduction in antioxidants, high amounts of phenolics with potent antioxidant activities are still found in cooked pulses