Abstract: In order to explore the effect of the extrusion stabilization of wheat bran and embryo on the properties of whole wheat foods, two kinds of 100% whole wheat noodles were prepared by addition of unextruded and extruded mixtures of wheat bran and embryo to wheat flour and they were compared for changes in quality characteristics such as nutrients, color, flavor and storage stability. The results showed no significant differences in multiple macronutrients and mineral elements between the two kinds of whole wheat noodles (P > 0.05). Some nutrient levels were changed by no more than 10%. Extrusion was conducive to the release of β-carotene, vitamin B2, and bioactive phytochemicals, but not to the maintenance of vitamin B6 and folic acid. Moreover, upon extrusion, the contents of linoleic acid, α-linolenic acid, C11:0, and total and some individual amino acids were increased significantly (P < 0.05), the color quality was improved, and the response values of the electronic nose were greatly decreased; the fatty acid and acidity values were significantly lowered (P < 0.05) and the storage quality was more stable. Compared with ordinary wheat noodles, the contents of macronutrients, vitamins (not including β-carotene), mineral elements and bioactive phytochemicals in whole wheat noodles with extruded mixtures of wheat bran and embryo were significantly increased (P < 0.05). Among them, a larger increase was seen in the contents of fat, ash, vitamin B1, vitamin B2, vitamin B6, niacin, folic acid, total phenols and total dietary fibers. The whole wheat noodles contained more unsaturated fatty acids, and showed a significant increase in the contents of total amino acids and all individual amino acids (P < 0.05) except glutamate, proline and cystine (P > 0.05). However, the color was deepened, the response values of the electronic nose were increased observably, and the fatty acid and acidity values were elevated significantly (P < 0.05). Conclusively, this study demonstrates that whole wheat noodles have a high nutritional value, a deeper color and increased contents of flavor components than ordinary wheat noodles. The extrusion stabilization of wheat bran and embryo can improve the quality and storage stability of whole wheat noodles.

Key words: wheat bran and embryo, extrusion stabilization, whole wheat noodles, quality evaluation