Preliminary site-dependent compositional evaluation of glucomannan and cyanide in Amorphophallus muelleri blume tubers from Southeast Sulawesi, Indonesia

Porang ( Amorphophallus muelleri Blume) is an important source of glucomannan, but information on within-region variation in glucomannan and cyanide remains limited. This exploratory study compared porang tubers collected from seven sampling locations (P1-P7) in Southeast Sulawesi, Indonesia. At each location, three farmer-managed farms were sampled, and three mature tubers were collected per farm; the nine tubers were pooled to form one site composite, and laboratory determinations were performed in triplicate. Fresh tuber moisture was measured on a fresh weight basis, whereas the recovered glucomannan-rich fraction, total cyanide, and supporting compositional variables were reported on a dry weight basis. Because pooling produced one biological composite per location, site-to-site differences were evaluated descriptively rather than by inferential statistics. The recovered glucomannan-rich fraction ranged from 51.47% to 69.09%, with the highest observed value in P6, whereas total cyanide ranged from 32.17 to 86.12 mg HCN equivalents/kg dry matter, with the lowest observed value in P3. These results indicate site-associated variation in the two primary compositional attributes evaluated in this study but do not establish causal effects of soil type, elevation, or topography, nor do they establish regional land suitability, processing safety, or economic superiority. The observed profiles warrant confirmation through independently replicated, multi-season sampling and fully documented analytical validation. Overall, the study provides a descriptive baseline for more rigorous evaluation of glucomannan and cyanide variation in porang raw materials from Southeast Sulawesi.