Storage Quality and Shelf Life Prediction of Macadamia Kernels under Different Packing Treatments and Storage Temperatures

In this study, the changes in the water content, acid value, peroxide value, and antioxidant activity of macadamia kernels were determined at different storage temperatures (4 ℃, normal temperature and 60 ℃) in 5 packaging systems, including conventional packaging, vacuum packaging, vacuum deoxidizer packaging, nitrogen packaging and nitrogen deoxidizer packaging, and a kinetic model to predict the shelf life of macadamia kernels was established based on the peroxide value. The results showed that nitrogen and nitrogen deoxidizer packaging significantly inhibited the increase of acid value and peroxide value, reduced oxidative rancidity, slowed down the decline of total phenol content, and maintain high 1, 1-diphenyl-2-picrylhydrazyl, 2, 2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) cationic radical and hydroxyl radical scavenging ability in macadamia kernels. Peroxide value was positively correlated with both storage temperature and time (P < 0.05), and its changes were fitted to a first-order kinetic model. The Arrhenius equation had good fitness, and the error of the prediction model was less than 14%. Nitrogen packaging had the longest shelf life, with measured values of 215, 180, and 108 days at 4 ℃, normal temperature, and 60 ℃, respectively, followed by nitrogen deoxidizer packaging, with measured values of 205, 175, and 104 days, respectively.