Effect of freeze-thaw treatment on the quality and flavor of Nang

Abstract

Freezing processing has been used widely to improve the sensory quality and solve the problems induced by fungi. In this study, the effects of frozen temperature (−20, −30, −40, −50, −60°C), frozen time (30, 40, 50, 60, 70 min), thawing temperature (25, 30, 35, 40, 45°C) and thawing time (10, 15, 20, 25, 30 min) on sensory quality, texture characteristics and flavor of Nang were studied. The results showed that the order of the factors affecting the sensory quality of Nang was frozen temperature > thawing time > frozen time > thawing temperature. The optimum processing conditions were to freeze at −50°C for 50 min and thaw at 40°C for 20 min. The correlation analysis between sensory quality and texture profile analysis (TPA) showed that the highest or the lowest TPA values of the core and edge of Nang did not correspond to the best sensory quality. Frozen treatment affected the characteristic flavor of Nang obviously. There were 15 of flavor substances with a significant increase or decrease among the 41 characteristic ones identified. This study is of great significance for the production and promotion of traditional staple food in Xinjiang.