Effects of Drying Methods on Moisture Reduction and Phenolic Content of Kepok Banana Peel (

The high moisture content of kepok banana peel (Musa paradisiaca), a nutrient-rich by-product, limited its direct use as substrate for black soldier fly larvae (BSFL). This study aimed to evaluate the effects of three drying methods: air drying (P1); oven-drying at 40°C (P2); and oven-drying at 60°C (P3), on the moisture reduction, moisture ratio (MR), and total phenolic content (TPC) of banana peels over six days. Moisture content was determined using a two-stage gravimetric oven-drying method, MR was modeled using the Page equation, and TPC was determined using Folin-Ciocalteu method. All treatments began with similar initial moisture content (86.41%) and phenolic content (134.84 mg GAE/g). P3 reached the optimal BSFL substrate moisture range (64.77%) by day 3 but continued drying to 3.93% by day 6, requiring rehydration. P1 and P2 reached the target moisture range more gradually by day 6 (60.63% and 63.43%), show better energy efficiency. P1 and P2 preserved most phenolics, while P3 drying caused a >90% loss. These findings suggest that air drying, low-temperature, or short-duration high-temperature drying treatments could optimize substrate preparation for BSFL while preserving functional compounds.