Impact of Agrovoltaic Shading on the Chemical Composition and Antioxidant Capacity of Radishes (Raphanus sativus L.)

Abstract

Agrovoltaic systems, which combine photovoltaic panels with agriculture, can increase production and modify plant metabolism due to shading stress. This study aimed to compare radish cultivation in an agrovoltaic system with 10° and 50° shading angles versus a conventional crop through physical and chemical analyses. The cultivation was automated using sensors to monitor pH, humidity, solar radiation, and NPK levels. Following AOAC standards, the proximal composition was determined. ICP-MS was used to determine total mineral content in both leaves and bulbs, and antioxidant capacity was assessed using the DPPH and FRAP methods. The results showed that shading significantly affected the treatments, with radishes showing larger bulb size and leaf area in the treatment with a 10° solar panel inclination. No significant differences were observed in the proximal composition, but protein content in the leaves ranged from 2.60 to 2.99 g/100g fresh weight. The leaves contained a higher concentration of minerals compared to the bulbs. Significant differences were also observed in total phenolic compounds and flavonoids, with higher levels in the leaves. Regarding antioxidant activity, the bulbs exhibited greater DPPH radical inhibition (82%-88%), while the antioxidant activity measured using the FRAP method was higher in the control group. These results suggest that shading influences the synthesis of secondary metabolites, regulating the concentration of phenolics and flavonoids, which affects antioxidant activity.