COMPARATIVE ANALYSIS OF SENSORY PROFILES OF TEMPEH PREPARED WITH AMARANTH vs. SOY USING Rhizopus oligosporus AS INOCULUM

Abstract

The study aimed to develop a Rhizopus oligosporus starter culture for using it in the preparation of amaranth-based and soy-based tempeh and to compare their resulting sensory profiles using the Rate-All-That-Apply (RATA) technique. In this study, the Rhizopus oligosporus inoculum for tempeh preparation was produced by Solid State Fermentation in rice. During inoculum production, the effects of initial pH (4.5, 5.0, 5.5, 6.0, and 6.5) and initial temperature (25, 30, 35, and 40 °C) were determined. Products generated during fungal metabolism were analyzed: organic acid content by titration, lactic acid production by spectroscopy, and the final pH of the medium. Once the appropriate conditions for inoculum production were determined, a comparative analysis of the sensory profiles of amaranth-based and soy-based tempeh was performed using the Rate That Apply (RATA) technique. The results showed that the highest lactic acid production was obtained when the initial pH of the medium was adjusted to pH 5.5 (1.75 g L–1) and at 40 °C (1.85 g L–1). Likewise, the highest organic acid production was observed at an initial pH of 5.0 (0.066 g L–1), pH 6.0 (0.105 g L–1), and at 35 °C (0.69 g L–1). Different sensory profiles were observed. The soy-based tempeh differed from the amaranth-based tempeh in its fishy odor and flavor. Therefore, the lactic acid content, organic acids, and final pH of the medium are influenced by the initial pH and temperature of the medium. The sensory profile of tempeh is influenced by the raw materials used in its preparation.