Effects of major drying methods on the stability and retention of vitamin C, B group vitamins, fat-soluble vitamins, and carotenoids in kiwifruits

This study investigates the effects of five drying methods—freeze, vacuum, microwave, convective, and natural—on the nutritional and visual quality of kiwifruit, focusing on the vitamin C, B-group vitamins, fat-soluble vitamins, and carotenoids. Fresh samples contained 5.57 mg/g ascorbic acid, and freeze drying retained the highest level (3.13 mg/g), followed by vacuum drying (2.63 mg/g), while natural and convective drying resulted in severe reductions (1.06 and 1.21 mg/g). Riboflavin, initially 1.59 μg/g, decreased to 0.91 μg/g after freeze drying, 0.82 μg/g after vacuum drying, and 0.54 μg/g under natural drying. Carotenoids followed similar trends, with β-carotene declining from 2.88 μg/g in fresh samples…