Abstract
Over-fermented tempe, known as tempe semangit, is popular in Indonesian culture, especially in Java, as an umami seasoning in traditional foods. The objective of this study was to characterize taste-active compounds in water soluble extracts of over-fermented tempe. Over-fermented tempe was prepared from fresh tempe in which the fermentation was prolonged (0 to 96 h). Free amino acids in the water soluble extract were analyzed and characterized for their taste activity values. Water soluble extracts contained umami and bitter tasting free amino acids at relatively high concentrations. Their umami and bitter taste activity values were higher than the taste threshold concentration. Water soluble extract from 72 h over-fermentation had a higher umami taste activity value than bitter taste activity, exhibiting the highest umami taste dilution factor. The high-performance liquid chromatography profile of water soluble extract fractions obtained using Sephadex G-25 gel filtration chromatography demonstrated that fractions having higher umami taste intensity had more hydrophilic components than hydrophobic components.
ACKNOWLEDGMENTS
The authors gratefully thank Professor Yasuyuki Hashidoko of the Agricultural Faculty, Hokkaido University, Japan for his helpful advice.
FUNDING
This research was supported by grants funded by the Indonesian Ministry of National Education through the Competitive Funding called Hibah Kompetensi (HIKOM) 2012.