Extraction of glucomannan from porang (Amorphophallus muelleri Blume) with freeze-thaw cycles pre-treatment

Amorphophallus muelleri Blume tuber, which is called porang in Indonesia, one of the biggest glucomannan sources next to konjac tuber. Glucomannan commonly produced by ethanol extraction technique. This study aimed propose freeze-thaw cycles (FTC) pre-treatments with two factors including freezing time and number before step investigated impact on physicochemical morphological properties extracted glucomannan. The obtained data were statistically tested means multivariate analysis variance (MANOVA) post-hoc Duncan tests at a significance level (P) 0.05. treated samples compared control sample (without FTC) Dunnett’s test. result showed that FTC changed morphology from smooth become porous globes showing more fissures its surface. Generally, treatments affected except for protein calcium oxalate contents. did not significantly affect protein, starch, test results indicated ash, carbohydrate (glucomannan), color different those sample.