CHANGES IN METABOLITE PROFILE AND SENSORY CHARACTERISTICS DURING THE PROCESSING OF TEMPE GEMBUS

Abstract

Tempe gembus is a traditional Indonesian fermented food produced from okara, a byproduct of tofu production. This study characterised the metabolite profile of tempe gembus during its processing and correlated the metabolite changes with sensory characteristics. Samples of tempe gembus from different processing stages, from fresh and steamed okara, to tempe gembus fermented for up to 72 hours, were analysed using gas chromatography-mass spectrometry (GC-MS)-based metabolomics, while sensory evaluation was conducted using the Rate-All-That-Apply (RATA) method. The GC-MS metabolomics result revealed that fresh okara was dominated by metabolites associated with carbohydrates, whereas tempe gembus samples were dominated by amino acids, and metabolites associated with amino acid and lipid metabolism. RATA results showed that tempe gembus at 48 hours of fermentation had a significantly more intense bitter taste than at 36 hours, correlating with the peaking of bitter-tasting amino acids in its metabolite profile. Bioactive compounds, including genistein and 4-aminobutyric acid, and antinutritional factors were also identified along with their changes throughout fermentation. This study is the first to comprehensively report metabolite changes throughout tempe gembus production using GC-MS-based metabolomics, and relate them to sensory characteristics, supporting the potential of tempe gembus as a sustainable functional food.