| Based on the integrating plenty of research results of predecessors, the study adopts the method of solid state fermentation with mixed bacteria to ferment rapeseed meal. The study firstly adds Bacillus natto, and then Lactobacillus brevis added. As for the setting of evaluation indices, the ratio between natto kinase enzyme activity and the content of small peptides were taken as the indices of comprehensive evaluation. After optimizing fermentation, the changes of the nutrient substances and active ingredients during whole fermentation of rapeseed meal are analyzed and determined. In addition, the healthcare function of rapeseed meal fermentated is evaluated by Caenorhabditis elegans. These studies provide theoretical basis and technological parameters for pabular industrialization as well as developing a new-type feed which takes rapeseed meal as the carrier and is rich in various viable organisms of probiotics and health efficacy. The paper mainly obtains the following.1. The appropriate situation for expanding Bacillus natto and Lactobacillus brevis growth curve were12h and18h, the count result showed that, they had reached the inoculation requirements; Bacillus natto and Lactobacillus brevis were used to ferment solid-state rapeseed meal by single strain and mixed strains,that are carried out to study the effect of fermentation on the quantity of living bacteria, nattokinase and trichloroacetic acid soluble nitrogen (TCA-NSI) as indices to determined the inoculum mode and fermentation time; inoculating Bacillus natto at first,2days later inoculating Lactobacillus brevis and fermentated time is4d. After the parameters of fermenting rapseed meal were determined, the fermentation conditions were studied via single-factor test and response surface methodology which was adopted according to box-behnken experiment design principle with3factors and3levels parameters the result were as follows:the inoculation amount was1.5%, the fermentation temperature was37℃, the solid to liquid is1:1.05, optimum inoculum propotion is1:1and the pH of the mix culture medium is nautual. The nattokinase enzyme activity reached3785.702U/g, and TCA-NSI content was5.36%after96h fermentation.2. The measuring of various substances content in the rapeseed meal raw materials and fermentation products indicated that the effect of the fermentation was very well. The main conclusions of the experiments were as follows:After fermentation, the crude protein and the crude fat content were respectively increased by6.27%and33.1%, reducing sugar increased from0.63%to4.59%,total sugar in fermented rapeseed meal were31.9%lower than that in rapeseed meal, ash content slightly increased by0.26%.The small peptides content of rapeseed meal increased from0.53%to5.38%,the increasing rate was896.3%.Total amino acids and total essential amino acid in fermented rapeseed meal respectively increased by18.72%and26.34%compared to those in rapeseed meal,the majority of amino acid contenr increased significantly. In addition, the nattokinase enzyme activity was3785.7U/g after fermentation. The Bacillus natto and Lactobacillus brevis counts increased rapidly and maintained at about2.29×1010cfu/g and3.16×109cfu/g. Under these conditions the glucosinolates content of rapeseed meal decreased from29.9μmol/g to17.2μmol/g, degraded by42.5%, phytic acid was degraded by10.1%, tannic was degraded by5.4%, crude fiber contents decreases from8.45%to7.78%.3. The change of protein content in the process of fermentation of rapeseed meal was analyzed by SDS-PAGE. The results show that the content of small peptides increases remarkably with the increase of fermentation time. Additionally, the deepening of all the colors of electrophoretic band within the scope of the relative molecular mass of rapeseed protein proves that the total content of protein increases obviously in the process of fermentation.4. Using Caenorhabditis elegans as the model organism to study the effects of the aqueous extract of fermentated rapeseed meal whole process on Caenorhabditis elegans’ physic indices including lifespan, spawning and movement. The result shows:Mean lifespan and maximum lifespan of FRSM group (fermentaed rapeseed meal) were22.37d and33d. Compared with control group and RSM group (rapeseed meal) respectively increased by12.6%,9.8%and17.9%,12.5%.The total progenies of FRSM group were307, compared with control group and RSM group respectively increased by43.4%and24.8%; The head thrashes and body bends of FRSM group were increased by39.9%and113.3%, compared with RSM group was increased by38.7%and81.5%. And each indicator between RSM and control group had no significant difference. It proved that the functional component in rapeseed meal after fermentation can produce a protective effection on the physical level of C.elegans. |
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