ZnCl₂ treatment improves nutrient quality and Zn accumulation in peanut seeds and sprouts

Peanut is a popular food due to its high nutrient content. The effects of ZnCl₂ on peanut seed germination, fatty acid and sugar contents, vitamin biosynthesis, antioxidant content, and Zn assimilation were evaluated in this study. Treatment with ZnCl₂ significantly improved the germination rate, enhanced reactive oxygen species production and reduced the content of total fatty acids in peanut seed and sprout. However, ZnCl₂ treatment did not reduce total sugar or total protein relative to the control. Germination promoted the biosynthesis of phenolics and resveratrol and increased the antioxidant capacity, as evaluated by Fe³⁺ reducing power and 2,2-diphenyl-1-picrylhydrazyl radical scavenging ability, especially under Zn stress conditions. The vitamin content decreased in the following order among treatments: germinated seeds with ZnCl₂ treatment > germinated seeds without ZnCl₂ treatment > dormant seeds. Interestingly, Zn content was approximately five times higher in the germinated ZnCl₂-treated seeds compared to in the untreated germinated seeds and the dormant seeds. The results of this study provide a new method for producing healthy foods with enhanced vitamin content and antioxidant capacity.