Study On Extraction And Antioxidant Activity Of Morchella Protein

Morchella is one of famous wild edible mushrooms in the world. It is featured by tender and delicious taste and high nutritive and medicinal value. Morchella is mainly distributed in Eastern China. According to traditional Chinese medicine, morchella is nontoxic, sweet and cold in taste, and mild in property, having the effects of aiding digestion, coordinating intestines and stomach, regulating qi-flowing for eliminating phlegm, refreshing brain, and tonifying Yang and kidney. According to modern medical researches, active substance in morchella also has the effects of blood fat reduction, anti-fatigue, immunoregulation, anti-tumor, and anti-radiation. With entity of morchella as raw material, the author explored for the extraction process of morchella protein, analyzed relevant features of protein obtained, evaluated its nutritive value, and researched its resistance to oxidation. Main research contents of this topic are shown as follows:1. Research on extraction process of morchella protein:In this research, ultrasonic-assisted alkali dissolution and acid deposition method is used to extract morchella protein. At first, the author made a single factor experiment to inspect relevant factors and their effects on the extraction ratio of morchella protein. Then, the author made a Plackett-Burman screening test to specify notable factors in the extraction process of morchella protein, and optimized the extraction process through Box-Behnken central combination test and response surface hook face analytical method. At last, the author determined the optimal extraction process (pH value:11; extraction temperature:50℃; ultrasonic extraction time:60min). Under such condition, the extraction ratio is 71.44% for protein obtained.2. The author researched relevant features of protein separated from morchella, and tested its solubility, water absorption, oil absorbency, emulsifying property and foaming property.3. The author made amino acid composition analysis and nutritional evaluation for morchella protein, and tested its amino acid rating, chemical rating and essential amino acid index. According to the test result, morchella protein contains amino acids in complete categories and rich content. Essential amino-acid accounts for 39.99% of the total. The amino acid rating is 96.28. The chemical rating is 67.81. The calculated result of EAAI (essential amino acid index) is 0.9199 with FAO/WHO protein under standard mode as the datum.4. Research on resistance to oxidation of morchella protein. Resistance to oxidation of morchella protein is evaluated by testing its ability to eliminate and recovering DPPH free radical, superoxide anion, and hydroxyl radical. According to the test result, morchella protein has certain resistance to oxidation, and such resistance increases with the increase in concentration of protein solution. The highest ability to eliminating DPPH can reach 88.98%, close to VC.