Effects of Drying Methods on Moisture Reduction and Phenolic Content of Kepok Banana Peel (Musa paradisiaca) for Black Soldier Fly (Hermetia illucens) Substrate Preparation

Department of Nutrition and Feed Technology, Faculty of Animal Sciences, IPB University, Indonesia

^* Corresponding author: erika_laconi@apps.ipb.ac.id

Abstract

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.