Effect of drying temperature on quality of walnut

For the purpose of verifying the effect of drying temperature on quality of walnut, the diversification of moisture content and acid value and peroxide value and water activity in the drying process was determined in WUMI walnut and WEINING PAO walnut at the drying temperature of 40, 50, 60℃ and nature drying (CK) .The results showed that the content and activity value of water increased significantly and the value of acid and peroxide decreased significantly, the value of acid and peroxide was positive correlated to dehydration temperature, contents of nutrientsubstance increase as drying temperature increase.After 25h dehydration, the moisture content of two kinds of walnuts at the same temperature was not correlated, the value of acid and peroxide of processing 40, 50℃ and nature drying changes least and owned better taste while it took a long time, especially nature drying, with a long time but quality could not be guaranteed.The processing 60℃ owned the lowest water activity value and it had already reached secure water activity after 15h dehydration.It could prevent most of microorganisms from surviving and extended storage period effectively.Based on overall consideration such as quality, storage period and cost of production, the processing 60℃ with 15h was better for walnut drying.