Functional and nutritional properties of whole wheat flour as affected by organic/no-till cropping systems and physical/enzymatic treatments.

摘要

Consumers are increasingly interested in eating safe, healthy and sustainable foods as they better understand the importance of whole grain foods in human well-being and concerns on the sustainability of future agricultural production.;Significantly greater test weight, kernel diameter, kernel weight and lower hardness index were detected in soft wheat grown in no-till cropping systems, compared to conventional systems. Total phenolic content and antioxidant capacity of wheat grain were reduced by no-till cropping systems, partly due to increases in kernel size and weight. Lower protein content, lower SDS sedimentation volume and lower lactic acid and sucrose solvent retention capacity of no-till wheat may explain higher cookie diameter of no-till wheat.;Organic wheat tended to have larger kernels; lower phenolic content and total antioxidant capacity of organic wheat was likely due to a decreased proportion of aleurone and pericarp. Lower protein content, lower SDS sedimentation volume and lower solvent retention capacity were observed in organic soft wheat grown under very low fertility along with higher cookie diameter and sponge cake volume. In hard wheat, increased fertility tended to increase protein content regardless of cropping system and loaf volume of bread was not significantly different between organic and conventionally grown wheat.;Phytate additions to refined wheat flour at a 1% level increased mixograph mixing time and water absorption. Dough added with phytates showed lower total SDS-unextractable glutenin polymer content after mixing and fermentation, and HPLC profiles demonstrated that phytates caused a major shift towards lower molecular weight forms of unextractable glutenin polymers. Loaf volume of bread decreased with addition of phytates, probably due, at least in part, to the modified gluten properties; it is possible that the increased iron chelating capacity of phytates interrupted oxidative cross-linking of glutenins.;Bran pre-hydration, alone or with enzymes (cellulase, xylanase, cellulase+xylanase, phytase) increased soluble sugar content of bran. Soluble and insoluble fiber content decreased in pre-hydrated bran and in most enzyme treated bran, but soluble fiber content increased in xylanase treated bran. Loaf volume of whole wheat bread was greater with pre-hydrated bran at 25°C, the lower dose enzyme treated bran, and phytase-treated bran.