Flavor of Over-Fermented Tempeh Affected by Fermentation Period, Packaging, and Blanching

Over-fermented tempeh is traditional ingredient in Indonesian dishes, serving as a seasoning due to the unique flavor. Therefore, this study aimed to evaluate the effect of different fermentation periods, packaging types, and blanching processes on flavor of over-fermented tempeh powder. The results showed that tempeh amino acid composition increased with a prolonged fermentation period. However, the type of packaging and blanching process did not significantly affect these parameters. Changes in the concentration of chemical composition, such as amino acids and sugar, affected the sensory perception. Longer fermentation period was found to increase the amounts of amino acids contributing to umami and bitter tastes, while sugar content decreased with extended fermentation and in samples subjected to blanching. Nucleotide composition umami taste was more pronounced in plastic samples and those not subjected to blanching. Sensory evaluation also showed variations in the intensity of umami, bitter, sour, sweet tastes, and pungent, woody, floury, and rancid flavor. Based on the results, optimal fermentation period for producing over-fermented tempeh powder was approximately seven days, where the compositions of sugars, amino acids, and nucleotides remained relatively high. After complete fermentation, the concentration of bitter amino acids was excessively high and remained acceptable to consumers. These results showed the effect of fermentation period on flavor profile of over-fermented tempeh powder, providing valuable insights for application in food product development.