Indonesian tapé ketan fermentation.

Area of Science:

• Microbiology and Food Science
• Fermentation Technology
• Biochemistry

Background:

• Indonesian tapé ketan is a traditional fermented rice product.
• The fermentation process relies on a symbiotic relationship between mold (Amylomyces rouxii) and yeast (Endomycopsis burtonii).
• Understanding the biochemical transformations is crucial for optimizing tapé ketan production.

Purpose of the Study:

• To investigate the biochemical changes during Indonesian tapé ketan fermentation.
• To compare the effects of Amylomyces rouxii alone versus in combination with Endomycopsis burtonii.
• To determine optimal fermentation time and conditions for consumption.

Main Methods:

• Controlled fermentation of steamed rice using Amylomyces rouxii and Endomycopsis burtonii at 30°C.
• Analysis of substrate composition: total solids, crude protein, soluble solids, starch, reducing sugars, and ethanol content.
• Monitoring of pH, total acidity, and volatile acidity throughout the fermentation process.

Main Results:

• Fermentation for 36-48 hours at 30°C yields a product ready for consumption.
• The combination of mold and yeast reduced total solids by 50% and increased crude protein to 16.5% in 192 hours.
• Maximum ethanol concentration (8% v/v) and acidity (7.8 meq H/100ml) were achieved with the mold-yeast combination.

Conclusions:

• Amylomyces rouxii and Endomycopsis burtonii synergistically enhance nutritional value and ethanol production in tapé ketan.
• The combined fermentation is essential for developing the characteristic aroma and flavor of Indonesian tapé ketan.
• Specific biochemical changes, including starch degradation and sugar formation, are critical for product quality.