Study on the characteristics of Lactobacillus plantarum TY-Y10
[Objective]The objective of the study was to assess the growth curve,acid production capac-ity,acid tolerance,and bile salt tolerance of Lactobacillus plantarum TY-Y10(TY-Y10)and to investigate its viability and antioxidant properties under heat inactivation.[Method]The growth curve of the strain was determined using spectrophotometry,acid production capacity was evaluated through pH change curves,and the survival rate of viable bacteria in acidic and high-bile salt environments was determined through plate counting.The antioxidant capacity of TY-Y10 was assessed using DPPH and hydroxyl free radical scaveng-ing rates as well as reducing ability under live and heat-inactivated conditions at various temperatures.[Result]Our results showed that TY-Y10 entered the logarithmic phase after 4 hours of growth in MRS medium and reached a stable phase after 14 hours.The pH dropped below 4.0 after 12 hours.The survival rates of the strain were 69.62%,76.44%,102.68%,236.00%and 570.80%when cultured in environ-ments with pH values of 2.5,3.0,3.5,4.0 and 4.5 for 3 hours.In the presence of bile salt concentrations of 0.1%,0.2%,and 0.3%in MRS medium,the survival rates were 109.94%,101.95%,and 100.23%after 8 hours,respectively.The DPPH clearance rates for TY-Y10 live bacteria,80℃heat-inactivated bacteria,and 100℃heat-inactivated bacteria were 38.38%,41.37%and 32.41%,respectively.The hydroxyl free radical clearance rates were 80.55%,90.53%and 76.80%,and the reducing ability was 169,231 and 93 μmol/L of L-cysteine hydrochloride equivalent.Moreover,the DPPH clearance rates for TY-Y10 live bac-teria supernatant,80℃heat-inactivated supernatant,and 100℃heat-inactivated supernatant were 29.97%,15.85%and 14.22%,respectively.The hydroxyl radical clearance rates were 32.64%,48.00%,and 67.83%,and the reducing ability was 72,128 and 66 μmol/L of L-cysteine hydrochloride equivalent.[Conclusion]In conclusion,TY-Y10 demonstrated robust reproductive ability,strong acid production,acid resistance,and bile salt resistance.Both live and heat-inactivated TY-Y10 exhibited significant in vitro anti-oxidant activity,with the 80℃ heat-inactivated bacteria showing the highest antioxidant activity.