Storage properties of walnuts dried by drum catalytic infrared-hot air

The kinetic processes of oxidative rancidity reaction of walnut under different storage temperatures and times were studied, by using acid value and peroxide value as evaluation indexes. The prediction models for evaluating the shelf life of walnut under different storage temperatures were established. The results showed that the acid and peroxide values of walnut increased with the prolonging of storage time. The increases of walnut acid and peroxide values were the lowest in the treatment of combined dr-ying of drum catalytic infrared with a variable temperature and hot air. After 90 days of storage, the acid and peroxide values of walnut were 1. 27 mg/g and 0.019 9 g/100 g, followed by the combined drying of drum catalytic infrared with a constant temperature and hot air and the highest was single hot air drying, which did not exceed the national standard and all had good quality. The oxidation and rancidity reaction of walnut accorded with the first-order chemical reaction kinetics model. In addition, the shelf-life models of walnut dried by the combined drying of drum catalytic infrared with a variable temperature and hot air were established by acid value and peroxide value respectively. The R - values were all greater than 0.99, and the relative error was less than 9%. It showed that the prediction model could better predict the shelf life of walnut under the storage condition of 5〜35 。C.