Evaluation of quality deterioration of dried whole-wheat noodles with extrusion-stabilized bran and germ during storage

Abstract

The prepared DWWN samples were placed under 60% humidity, at 25 °C, 35 °C, and 45 °C and stored for 300 days, 150 days, and 35 days, respectively. Changes in chemical-physical, volatile compounds and sensory quality of DWWN were monitored during storage. During the whole storage period, the water activity ranged from 0.60 to 0.66, and the free fatty acid showed an overall increasing trend. As the storage temperature increased, the acidity value showed a significant logarithmic increasing trend; the relative content of ketones, esters and pyrazines increased, and the aldehydes decreased. The content of linolenic acid, trans-linoleic acid and palmitoleic acid increased mutationally for a certain period of time, then decreased rapidly and became stable when stored at 35 °C and 45 °C. The freshness decreased, the inherent fresh wheat aroma diminished with the prolongation of storage time, and the higher storage temperature, the worse deterioration within a short time for DWWN. The changes in the relative content of 44 volatile flavor compounds were evaluated through GARS-PLS multivariate statistics, revealing that 10 identified compounds could be related to the loss in wheat aroma or the accumulation of unpleasant flavor. Combined with a correlation analysis of volatile compounds and physicochemical indexes, the quality of DWWN was mainly related to the acidity and free fatty acid, and closely related to the content of palmitoleic acid, linolenic acid and gadoleic acid.