Microwave pulsed vacuum drying (MPVD) revolutionizes wolfberry processing: synergistic effects on drying efficiency, microstructure, nutrient preservation and metabolomics.

Abstract

Dried wolfberry (Lycium barbarum L.) is valued for its nutrients, but conventional hot air drying (HAD) causes degradation and browning. This study compared microwave pulsed vacuum drying (MPVD) (4-6 W/g) with hot air drying (HAD). Microwave pulsed vacuum drying reduced drying time by 88.61%-92.5% and improved color, microstructure, and rehydration capacity. The 5 W treatment achieved the highest total sugar content (7.69 mg/g) and rehydration ratio (1.50). The 6 W treatment increased total phenolics by 119.50% and enhanced 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) scavenging rates by 31.57% and 6.26%, respectively. Microwave pulsed vacuum drying also preserved bioactive components by regulating pectin composition (57.51%-76.86% water-soluble pectin) and modulating metabolic pathways such as α-linolenic acid metabolism. This technology is a promising industrial technology for high-quality wolfberry processing.