Utilization of Rubber Seeds as Innovative Food Material: Effectiveness of Processing in Reducing HCN Content Pemanfaatan Biji Karet sebagai Bahan Pangan Inovatif: Efektivitas Pengolahan dalam Menurunkan Kandungan HCN

Abstract

Rubber seeds (Hevea brasiliensis) are an underutilized by-product of rubber plantations, containing high levels of protein and fat. However, their utilization as food is limited due to the presence of toxic hydrogen cyanide (HCN). This study aimed to evaluate the effectiveness of processing stages in reducing HCN levels in rubber seeds to produce safe and consumable “tempe chips” (keripik tempe biji balam). Fresh rubber seeds were collected from smallholder plantations in Penukal Abab Lematang Ilir Regency, South Sumatra, Indonesia. The processing steps included peeling, boiling (100 °C, 30–60 min), soaking (96 h with periodic water replacement and alum addition), fermentation using Rhizopus oligosporus (10 h), followed by frying and oven-drying. HCN content was analyzed using AOAC 2012 Official Method 973.19 and AOAC 915.03 (Titrimetric Method). Laboratory results indicated that the final product contained less than 0.1 mg/kg HCN, which is far below the safety limits established by BPOM RI (10 mg/kg) and the Codex Alimentarius (2019). Overall, the combined processing stages reduced HCN levels from approximately 300 mg/kg in raw seeds to nearly undetectable levels (>99.9%). These findings demonstrate that the integration of boiling, soaking, fermentation, and thermal processing is highly effective in detoxifying cyanogenic compounds while maintaining nutritional potential. Thus, tempe chips made from rubber seeds can be developed as a safe, nutritious, and economically valuable alternative local food product.