Effects of HHAIB Combined with AID on Drying Characteristics of Baby Cabbage

In order to overcome the disadvantages of long drying time and large nutrient loss in the traditional baby cabbage drying process, high-humidity hot air impingement blanching (HHAIB) combined with air impingement drying (AID) technology was explored. The effects of different HHAIB blanching times (0-240 s), blanching temperatures (100-120 ℃) and subsequent AID drying temperatures (50-70 ℃) on drying kinetics, nutrient (ascorbic acid and total phenol) retention effects, antioxidant activities (DPPH radical scavenging rate and ferric reducing antioxidant power), key enzymatic activities (peroxidase and polyphenol oxidase), rehydration behavior and color change were systematically investigated. The results showed that, compared with the unblanched samples, the optimal HHAIB pre-treatment not only shortened the drying time by 40 minutes (17.4%), but also increased the ascorbic acid content and total phenolic content by 161.3% and 10.6%, respectively. Furthermore, the DPPH radical scavenging rate and ferric reducing antioxidant power were increased by 31.3%, and 20.1%, respectively. Meanwhile, by effectively inhibiting the activities of polyphenol oxidase and peroxidase, the good color in the dried product was maintained. A mathematical model was established using Box-Behnken response surface design with the comprehensive quality score calculated by the coefficient of variation method as the response value. The optimal process parameters were determined as blanching temperature of 114 ℃, blanching time of 110 s, and drying temperature of 61 ℃. The predicted comprehensive quality score of the model was 0.839 under this condition, and the experimental validation value was 0.847 ± 0.011, with an error of 0.944%, which verified the reliability of the model. The study aimed to provide a novel technical approach and basis for high-quality drying of leafy vegetables.