Effects Of Debranning On The Properties Of Purple Waxy Wheat Flours And End Products

Purple waxy wheat was a new promising wheat variety with abundant micronutrients forhealth benefits. In the present study, purple waxy wheat was removed the harmfulcontaminants (pesticide residues, heavy metals, microorganisms and toxins) by debranning, inorder to reserve the most nutrition constituents in kernels. The effects of debranning andtempering conditions on the properties of purple waxy wheat flour were studied. Meanwhile,the effects of debranning on properties of purple waxy flour and noodles were investigated. Itcan provide certain reference data and theoretical basis for the purple of waxy wheatindustrialization development and promotion. The main results in the paper were as follows：1. With the increase of debranning time, flour yield increased gradually(64.50%-67.85%). Debranning had positive effects on ash, protein content, color, pasting andrheological properties of purple waxy wheat flour. Debranning decreased the gluten index offlour (66.79-60.43).The results showed the most desirable debranning time of purple waxywheat flour were5min, in other words, debranning levels were about5.4%.2. Tempering conditions were determined. The properties of purple waxy wheat flourwere obvious changes under the tempering condition. For example, flour yield, the ash andwet gluten content, pasting and rheological properties. The best conditions were: purple waxywheat after debranning5min raised to15%moisture content and tempered6h at25℃.3. Added the purple waxy wheat flour to regular bread flour could significantly improvethe sensory quality and total score of bread. Added purple waxy wheat could not onlyimprove taste of bread, but also extend the shelf life of the bread in a certain extent. Purplewaxy wheat flour made by the debranning5min which was added15%into common breadflour that could improve significantly qualities of bread and reduce the bread of hardness in ashort time.4. The effects of debranning on properties of purple waxy flour were different. With theincrease of debranning time, debranning decreased the particle size (26.31-22.44m) andincreased brightness as well as pasting properties; decreased the wet gluten content(45.65%-42.15%). Meanwhile, debranning decreased the ash and protein content, butimproved rheological properties and increased processing quality of purple waxy flour.Debranning decreased the content of total phenolic and flavonoids. The DPPH scavengingrate also reduced0.33%-1.48%.5. The effects of debranning on qualities of noodles made with the purple waxy flourswere diverse. The break rate of purple waxy noodle in processing was≤5%. With the increase of debranning time, the best cooking time of noodles decreased gradually (12.05-6.46min)and rupture strength increased gradually (20.43-39.87g). Sensory quality of noodlesincreased and textural properties improved obviously. The total phenolic and flavonoidscontent of purple waxy noodles increased after cooking. The DPPH scavenging rate increased0.48%-1.96%. The results showed that purple waxy flour after debranning can significantlyimprove the processing property of the noodles.