Effect of Premna microphylla turcz leaves' extract addition on physicochemical and antioxidant properties of packed tofu by lactic fermentation

In the present study, Premna microphylla turcz leaves (PMTLs) containing rich pectin and isoflavones were introduced to prepare packed tofu coagulated by lactic fermentation, in order to promote its physicochemical and functional properties. Results showed that the final storage (G ') moduli of packed tofu added with PMTL extracts range from 195.2 +/- 5.6 Pa to 420.6 +/- 10.3 Pa, which were significantly higher (P < 0.05) than the control (PMTL-free, 99.5 +/- 8.3 Pa). The hardness, gumminess and chewiness of packed tofu added with 0.8% (w/w) PMTL extracts were 1.43-1.49 times higher than the control without decreasing its water-holding capacity and exhibited the highest scores of overall acceptability, which was recommended as the most acceptable concentration. The total phenolic and flavonoid contents of 0.8%-PMTL supplementation in packed tofu were 1.20 and 1.65 times higher than the control and showed enhanced antioxidant properties in DPPH radical-scavenging capacity, FRAP and RP.