The Effect of Annealing Modification on Increasing Glucomannan Content of Porang (Amorphophallus Muelleri Blume) Flour

Gusti Setiavani, Budi Suarti


This study aims to determine the effect of annealing on the glucomannan, protein, and water content of porang (Amorphophallus Muelleri Blume) flour. The material was a porang tuber from a farmer in Lubuk Pakam Regency in the second plant period. The method was completely randomized with temperature treatments of 30 °C, 40 °C, and 50 °C, and time; 3 hours, 4 hours, and 5 hours—parameters observation consisting of water content, protein, glucomannan, and yield. Annealing time significantly affects water content, glucomannan, and yield. It is related to the longer the time; the more water-soluble compounds were lost. It increases the amount of glucomannan and decreases the yield. The temperature significantly affects water content, protein level, glucomannan content, and yield. At the temperature reaches 40 degrees Celsius, the number of glucomannan increases, which is associated with the beginning of the gelatinization process. At the onset of gelatinization, the starch granule structure weakens, allowing it to be readily crushed and liberated from glucomannan. This study indicated that glucomannan content decreased significantly as the temperature increased to 50 °C. It is hypothesized that the gelatinization temperature of porang starch is low; therefore, gelatinization is complete at around 50 °C. However, it needs further research. The protein level decreases by increasing temperature due to protein denaturation. The annealing process at 40 °C for 5 hours gives the high glucomannan content. Glucomannan has a strong relationship with yield. The annealing process promised to be used in glucomannan production from porang tuber.


Porang; annealing; glucomannan; yield; gelatinization; starch

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