Effects Of Material And Maillard Post-Processing On The Antioxidant Activity Of Soy Sauce

The effect of raw materials and process condition on the antioxidant activety of soy sauce was studied in this paper.And the important contribution factors of the antioxidant of soy sauce were screened out.On the basis of this,melanoidins as one of important antioxidant components was extracted and purified.Besides,its antioxidant activity and antitumor activity were analyzed by vitro experiment.The main results are as follows:Firstly,the effects of wheat germ on antioxidant activities of Chinese traditional high-salt diluted soy sauce made with soybean,flour and wheat germ were investigated.Results showed that the more wheat germ was added,the higher antioxidant capacity of raw material or koji were,while the antioxidant capacity of soy sauce was not consistent with the mount of wheat germ.Besides,sample 2(S1)had the highest antioxidant activity,which was significantly higher than that of the control group sample 1(S0)(P<0.05).At the same time,the correlation analysis showed that the antioxidant activity of soy sauce had strong correlation with total phenols content and Maillard products(P<0.01),but there is little correlation with flavonoids.In conclusion,soy sauce antioxidant activity can be improved by using wheat germ instead of flour.Secondly,the effects of different maillard reprocessing methods on the antioxidant capacity of soy sauce were investigated by using wheat germ soy sauce(S1).It was found that heat or ultrasonic treatment could significantly enhance Maillard product and antioxidant activity of soy sauce,while ultrahigh pressure treatment had no significant effect.Moreover,flavor substances were measured by GC-MS which showed that active functional components such as aldehyde,ketone,phenol and furan content were increasing significantly after heat or ultrasonic treatment.According to the sensory evaluation analysis,it is necessary to select slightly mild conditions as severe hot or ultrasonic treatment conditions would cause anxious burnt flavour.Besides,the antioxidant activity of the heat treated soy sauce is significantly higher than that of the ultrasonic treatment.Therefore,appropriate heat treatment method can be used to improve the antioxidant activity of soy sauce.Finally,the crude extract of melanoidins was purified by D202 anion macroporous resin.Results showed that 0.89 g of melanoidins was made by filling 125 g dry resin,and the content of melanoidins was about 24.7 times before purification.The DPPH free radical and ABTS free radical scavenging ability of melanoidins were significantly higher than those of soy sauce,which proved that melanoidins was an important contributors to the antioxidant capacity of soy sauce.The antitumor activity of melanoidins was measured by MTT assay,which showed that it could inhibit the proliferation of tumor cells and displayed a certain dose-dependent.It was further found that the effects of melanoidins on the growth of human normal liver cells L02 were relatively small as the cell survival rate was all above 85%,which also proved that melanoidins itself has a certain anti-tumor effect.