| Both Ganoderma and Pleurotus nebrodensis contain high protein, low fat and highnutritional value. These species of fungi contain fungi polysaccharides, which has the functionof enhancing the immunity, reducing the blood lipids, scavenging free radicals, anti-aging,anti-virus, anti-tumor. Yoghurt has high nutritional value, with the economic development andthe improvement of people’s living standards, China’s yoghurt market is developing, thehealth-keeping yoghurt is the new trend of milk beverage, developing healthy functionalyoghurt has great market potential. In this experiment, through the orthogonal experiment todetermine the fermentation process of Ganoderma yoghurt and studied the changes of lacticacid bacteria physicochemical indexes of Ganoderma yoghurt in the process of storage.Through the response surface experiment of4factors and3levels, to optimize fermentationprocess of the Ganoderma and Pleurotus nebrodensis yoghurt. Analyzed and evaluated thefermentation broth of Ganoderma and Pleurotus nebrodensis, the lactic acid bacteria inyoghurts, flavor substances and functional ingredients. And studying the products’ health carecharacters; crudely separating the fermentation broth of Ganoderma and Pleurotusnebrodensis and getting crude extract of polysaccharide, polypeptide and protein, and makingit into yoghurt, then measuring the physicochemical indexes, and thus to determine the effectof every component on yoghurt.1. Through the orthogonal experiments, to dertermine the best fermentation process is:the ratio of Streptococcus thermophilus and Lactobacillus bulgaricus inoculated is1:1,inoculating amount is6%(volume ratio), the amount of sucrose added is6%(weight volumeratio), the amount of broth added is20%(volume ratio), and the fermentation time is4h.In storage, the amount of lactic acid bacteria in the products reached to the maximumlevel (6.5*109CFU/mL) in the first day, then it decreased; in the period of storage, the acidityincreased gradually and later the acidification was weaker; the viscosity and content ofacetaldehyde and butanedione presented the firstly rising and then declining trend, the flavorand taste were better, and all in line with the national standards.2. Determined the optimum range of different factors by the single factor experiments.Then determined the optimum conditions of fermentation process by a4-factors3-levels response surface experiment. The optimum conditions are: the ratio of Streptococcusthermophilus and Bacillus acidophilus inoculated is1.2:1, the ratio of Ganoderma andPleurotus nebrodensis fermentation broth added is2.24:1and the adding amount is20%(volume ratio), the adding amount of CMC is0.21%(weight volume ratio),the temperature is41℃.3. Analyzed and evaluated the lactic acid bacteria, flavor substances and functionalcomponents of both fungi fermented yoghurt; the amount of lactic acid bacteria in fungifermented yoghurt can reach to108CFU/ml; WHC reaches to35.96%, in good stability;Amino acid is39.53mmol/L, polysaccharides is averagely0.275mg/mL, the averageconcentration of acetaldehyde is27.04mg/L, the average concentration of butanedione is10.27mg/L; the number of lactic acid bacteria increased apparently, acidity and WHCincreased slightly, more protein degradation and amino acid concentration increased;polysaccharides increased apparently, the content of acetaldehyde and butanedione was higher,it has a better flavor and mouthfeel.4. Crudely separating the fermentation broth of Ganoderma, Pleurotus nebrodensis andshitake mushroom to get polysaccharides, proteins, peptides and other functional components.Add these components into milk respectively and make it into yoghurt. Finally, results showthat the polysaccharides extracts have distinct promoting effect on the lactic acid bacteria andcan improve the texture of yoghurt, increase the content of acetaldehyde; the protein extractsfrom the3kinds of broth can increase the content of amino acid; the peptide extracts canpromote the synthesis of butanedione. |
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