Detoxification,Enzymatic Hydrolysis Of Peanut Dregs And Release Of Amino Acid In Its Hydrolysate

Peanut dregs is the coproduct of peanut after pressing oil. National Statistic Bureau reported that the content of peanut dregs in 2005 are 5.7 million tons increased by 6.1%. In Guangdong Province there are over 0.78 million tons every year and in Guangzhou it is 0.28 million tons. Peanut dregs is rich in protein, however, they are used for feedstuff for its denaturalization and being affected by aflatoxin. In this paper, we studied the ways of detoxification, found the optimization condition of enzymatic hydrolysis, and then analyzed the discipline on release of amino acid in order to provide theory for the further study of peanut dregs.Firstly, we mensurated the basic content of peanut dregs and found that it is a material with high protein and low fat. The content of aflatoxin is (105±2)μg/kg. Then we studied three ways to detoxification, which is high temperature with alkali, H2O2 treatment and treated by different filters. The results are as follows. The content of aflatoxin in enzymatic hydrolysate trends to reduce and then comes to balance with the development of enzymatic hydrolysis; out of the three ways to detoxification, high temperature with alkali is the best and it does good to enzymatic hydrolysis. After treated by 121℃with pH10 for 60min, the rate of degrading aflatoxin is 84.5% and it comes to 0.344μg/L in enzymatic hydrolysate; When treated by H2O2, it is ineffective in low concentration, but it is effective in 1600mg/kg, at this time, the content of aflatoxin in enzymatic hydrolysate is 0.104μg/L, the rate of degrading aflatoxin is 94.87%. However, H2O2 treatment does no good to the following enzymatic hydrolysis; as for different filters, the active carbon is the best of all, meanwhile the losing rate of AN is as high as 7.03%. Considering cost of experiment and the PR, we choose to treat under 121℃with pH10 for 60min and then filtered by common filter paper, the content of aflatoxin in enzymatic hydrolysate comes to 0.244μg/L.Then we studied the enzymatic hydrolysis condition with Alcalase2.4L, Protamex, Neutrase, Flavourzyme, Papain, PTN6.0S, found suitable enzymes and then optimized with response surface analysis. The results are as follows. Alcalase2.4L, Flavourzyme, PTN6.0S do good to enzymatic hydrolysis. And the optimum condition of PTN6.0S and Flavourzyme (simultaneous hydrolysis) is: ratio 3:1, 51℃, pH8.5, the content of enzyme 1% and enzymatic hydrolysis for 60h. Through three repeated experiments, the PR is 63.33%±0.15%, DH is 22.14%±0.08%.Finally, we studied the release of amino acid. The results show that there are eighteen free amino acid in peanut protein, of those there are eight kinds of necessary amino acid. Glu, Asp, Gly, Ala are rich in peanut protein, which is separately 21.96%,9.91%,6.84% and 4.34% , tasty amino acid is 43.05%, and necessary amino acid is 26.65%, campared to the total amino acid; the free amino acid increased with the development of enzymatic hydrolysis and the content treated by two kinds of enzyme is higher than that treated by one kind of enzyme; the content of free amino acid increased after detoxification, especially for PTN6.0S and PTN6.0S with Flavorenzyme, and the enzymatic hydrolysate can be used as nutrition material; Each enzyme has its own reactive sites, the amino acid in reactive sites and dydrophilic free amino acid are released initially; the result also shows that enzyme admixture has more reactive sites than that of one enzyme. From the composition of amino acid, we can see that PTN6.0S and Flavorenzyme enzyme admixture is more suitable in enzyme hydrolysis than Alcalase 2.4L and Flavorenzyme enzyme admixture.