Antioxidant Activity and Soluble Protein Content of Tempeh Gembus Hydrolysate

Tempeh gembus is fermented soy-pulp product contains high protein and its bioactive peptide components has potential antioxidant activities. In this study bromelain enzyme was applied in tempeh gembus to break up peptides bond and released bioactive peptides and amino acids. The aim of this research was to analyse antioxidant activity and soluble protein of tempeh gembus hydrolysate. Experimental research with 4 bromelain enzymes were applied in tempeh gembus as 0 ppm, 5000 ppm, 8000 ppm, and 10000 ppm. Antioxidant activities were measured by ABTS and DPPH radicals test. Whil e soluble protein content was measured by Bradford test. In general, antioxidant activity of tempeh gembus was higher when measured by ABTS radical (63.14±1.16 – 92.85±2.28%) compared to DPPH radical (52.21±5.76 – 65.70±5.89%). Antioxidant activity of tempeh gembus hydrolysate in ABTS test differed significantly between treatment groups (p=0.001), but not on DPPH test (p=0.110). While soluble protein content of these protein hydrolysate were 0.58±0.05 – 0.78±0.11% and significantly differed between treatment groups (p=0.019). Antioxidant activity was significantly higher when measured by ABTS radical compared to DPPH radical with different
protein soluble content.