The Studies Of Microbial Fermentation Effects On SOD Activity In Garlic And Its Extraction Process

The garlic is the bulb of A llium sativum L. It is a perennial plant, which originated in the regions of eastern Asian and southern Europe and is cultivated over the word now, has extensive edible and medicinal value. Allicin, superoxide dismutase (SOD) are the main bioactive components of garlic. The main factors of effects on the consumption of garlic and garlic preparation are its pungent flavors. So, the key problem of improving utilization of garlic is how to decrease the fungent flavor and keep the bioactive ingredient. In this paper, the garlic was fermented by adding a certain microorganism to decrease fungent flavors and enhance the SOD activity, and the method of extracting garlic bioactivity components (SOD) were studied. It will provide some experimental data for exploitation and utilization of garlic resource in our country. In the first, the selected lactobacillus LC-012 was added in fermentation process to decrease pungent flavors and enhance the SOD activity in the garlic. The results showed that SOD activity and flavors of garlic varied with the fermentation time. The SOD activity increase with the passing of time during 45 days and the highest SOD activity was 47.8% at the 45^th day, and the pungent flavors have been decreased obviously. The garlic SOD PAGE combined with enzyme activity staining indicated that three main types of SOD in the fermented garlic are Mn-SOD, Cu, Zn-SOD, Fe-SOD, and Mn-SOD is the major type. The SDS-PAGE showed that there are four type peptides in fermented garlic, and the molecular weight vary from 5.46 to 1.52KDa.Secondly, the pure water was chose as an extractive reagent to extract the SOD in garlic. The optimal extracting conditions were that the ratio of the material and solution was 1:7(W/V), extracting time was 60min, and heat denatured for 20 min at 60℃ through selecting a series of experimental factors. On this condition, specific activity of SOD and enzyme activity were 16.58U/mg and 20.54U/ml, respectively.At last, the optimal technological parameters for purifying the SOD using ultrafiltration were obtained by simple factor of experiment and orthogonal experiments. At 32℃ and 0.15Mpa, the ultrafiltrating ratio is 90%, the SOD activity recovery could reach 88.1%, specific activity of SOD and enzyme activity were 21.1U/mg and 22.11U/ml, respectively. The bioactive components were concentrated by the nanoflication. Specific activity of SOD and unit enzyme activity can gain 30.04U/mg and 33.31 U/ml, respectively.