Abstract:The moisture content of fresh shelled walnuts was adjusted to 4%，8%，12%，and 16%，respectively，by two ways of hot-air drying and infrared radiation（IR） pretreatment combined with hot-air drying，and the changes in the texture，sensory，microstructure，the activities of lipoxygenase and polyphenol oxidase of the walnuts with different moisture contents stored for 90 days at 25 ℃ and 55%-65% humidity were analyzed. The shelf life of the walnuts with different moisture contents was predicted based on the first-order kinetic equation.The mechanism of IR pretreatment to improve the edible quality and prolong the shelf life of walnuts with high moisture contents was explored. The results showed that compared with the hot-air drying control group，IR pretreatment could significantly delay the increase in acid values（reduced by 4.79%-10.15%），peroxide values（reduced by 45.96%-72.48%），and malondialdehyde contents （reduced by 14.07%-32.79%），reduce the degradation of polyphenol and the production of soluble quinone，and inhibit the activities of lipoxygenase and polyphenol oxidase of walnuts with relatively higher moisture during storage，while the sensory characteristics were improved. With the increasing moisture contents，the hardness and peroxide value of walnut kernels decreased during storage；the total score of sensory evaluation first increased（IR8% was the highest） and then decreased. Meanwhile，the malondialdehyde content decreased，and the shelf life shortened. The lipoxygenase activity decreased；elasticity，acid value，soluble quinone content，and polyphenol oxidase activity increased.By considering the edible quality and shelf life，IR pretreatment of fresh shelled walnuts for two minutes，combined with hot-air drying for 8 h to control the moisture content of about 8% was the best treatment process.The walnuts with relatively higher moisture obtained by this process had both good texture and flavor，as well as a long shelf life.