| The apple is the pomaceous fruit of the apple tree, species Malus domestica in the rose family (Rosaceae) and is a perennial. It is one of the most widely cultivated tree fruits, and the most widely known of the many members of genus Malus that are utilized by humans. Apple pomace is the solid residue that remains following extraction of juice from ground apples. With the development of apple planting and processing industry, the production of apple pomace has been increased in a large scale. About 1.1 million metric tons of apple pomace is produced per year in China. With the development of the world's apple juice concentrate industry, the proportion of China's apple juice concentrate increased and export enlarged. But the pomace's disposal is a serious problem being highly biodegradable. Since it is a rich source of acids, carbohydrates, fibers, minerals and vitamin C, its disposal as a waste in the environment is a huge loss of precious natural resources. Production of fermentation based products from apple pomace (AP) is one of the attractive options due to the supply of substrates almost at a throwaway price, minimum land requirements and manufacture independent of weather conditions.In this thesis, apple orchards, apple juice concentrate processing plants and a supermarket in Shaanxi province are the collection sites, for acquisition of different cultivates apple skin sample, different growth stages of apple tree stems, leaves, flowers, young fruit, and orchard soil in three county towns, as water and soil from factory environment, and fresh apple pomace. Microorganisms with high activity of cellolase have been selected from these samples; strains which can use apple pomace efficiently between same ordinary edible fungi have been selected too, for the purpose of increasing protein content in fermentation products, and solving the difficult problem encountered before, such as incomplete fermentation procedure, low content of protein and serious peculiar smell.In this thesis, fresh apple pomace is studied as a test material. Three species, which selected from plants and environmental samples, were used in the solid state fermentation (SSF) processing. Then the researches are carried out for the topics of single fungus and mixed fungi co-fermentation, single factor test and perpendicular tests, different nitrogen sources, natural fermentation and man-controlled fermentation, etc. After ascertaining conditions of flask fermentation,30L solid fermentation machine has been used for large scale fermentation. In addition, solid state fermentation agent has been studied for the first time in apple pomace fermentation.1. From February to October in the year of 2008,236 pieces of samples were collected from different growth stages of Fuji apple trees' stems, leaves, flowers, young fruit, and orchard soil in three county towns, methods of tissue isolation and soil dilute plate have been used to isolate microorganisms from epiphytic and endophytic of the plant tissues and soil samples.570 isolates were investigated after single spore isolating and purifying, including 268 bacterial isolates and 202 fungal ones.2.120 pieces of samples were collected from different cultivated apples, apple juice concentrates production line, and apple juice concentrates which were expanding bags, both and places where apple pomace piled.207 isolates were investigated after isolating and purifying from the soil, water, apple pomace samples, including 121 bacterial isolates and 86 fungal ones.3. After 677 isolates above-mentioned selected preliminary by clear zone method (CZM),76 isolates were obtained and among them,5 strains were the most prospective in biological production of cellulase, which had high enzyme activities. Morphological characteristics show that these strains belong to four species, Fusarium sp., Saccharomyces sp., Trichoderma sp. and Aspergillus sp., respectively. Strain T23, T55, T62 were defined as dominant strains for their long Logarithmic growth phase and high cellulase activity in fermentation period by protein content and sensory index. Morphological characteristics and internal transcribed spacer (ITS) sequences show that strains were Saccharomyces cerevisiae, Candida utilis, Aspergillus niger, and were named as Saccharomyces cerevisiae Y1N4, Candida utilis Y2N3 and Aspergillus niger H1N3, respectively.4. Determine the main components of apple pomace, the results showed that the content of crude fiber was 14.7%, the content of crude protein was 4.2%. Apple pomace was not good enough as a fermentation material for its lack of nitrogen.5. The best fermentation condition in flasks was determined by single factor test. The results showed as follows:nitrogen was 10% content of bran, normal Sterilization method and the condition of 100℃,30min was good enough for kill all the microbes and spores, and content of water was 60%. Saccharomyces cerevisiae Y1N4, Candida utilis Y2N3 and Aspergillus niger H1N3 used in this study can increase protein content in fermentation medium by single fungus fermentation and mixed fungi fermentation. In fermentation period, both protein content and cellelase activity increase obviously. The study include mix ratio of fungi, species of fungi, Vaccination quantity and section fermentation, as well as the influence of temperature and fermentation time. The results showed that:Saccharomyces cerevisiae Y1N4, Candida utilis Y2N3 and Aspergillus niger H1N3 were mixed equally for inoculum, the vaccination quantity was 12%, Aspergillus niger H1N3 can be inoculum in first, Saccharomyces cerevisiae Y1N4 and Candida utilis Y2N3 were inoculum after 48h, the yield of protein reached 34.9%. On basis of fermentation by flasks,30L Horizontal automatic solid state fermenter was used to investigate the optimum conditions in large scale fermentation. The results showed that:when temperature was 27℃, aeration speed was 0.65 N-m3/h, inoculum was 600mL, and agitation speed was 15rpm, protein content reached optimum value,31.6%. Fermented apple pomace had a complete amino acids component, rich in Lys and other essential amino acids. There also were plenty of enzymes, nucleic acids, vitamins, inorganic salt and growth factors, which were superior to same plant source protein feed, and can instead of soybean meal and fish meal. In addition, rice husk can improve the aeration situation in medium, cellulase can increase degradation of fiber in material, all these would improve the quality of fermented products.6. Cultivating four kinds of edible fungi Pleurotus sajor-caju, Pleurotus nebrodensis, Hericium erinaceus and Agrocybe chaxinggu in apple pomace medium, the results showed that all these fungi grew well, and nitrogen bran (nearly 10% content) was better than urea, ammonium nitrogen, and ammonium sulfate. Protein content in apple pomace increased from 4% (before fermentation) to 20% (after fermentation). Chose Pleurotus sajor-caju as material to evaluate the influence of protein content with inorganic salts (KH2PO4, MgSO4 and ZnSO4), the result showed that inorganic salts can improve the content of protein in fermentation products. The optimal yield of protein reached26.178% when KH2PO4, MgSO4 and ZnSO4 were 18g/kg,3g/kg and 0.03g/kg, respectively.7. Six tested materials including methyl cellulose,β-circle dextrin (CD), soluble starch, chitosan, konjac flour and bran, were investigated for screening the best property solid state fermentation vector used in apple pomace fermentation. Previous studies on SSF vectors have not yet been reported. The results showed that the optimum vector of the highest adsorption ability was chitosan. Fermentation ability (FA) was positive relation with the adsorption power for yeast cells, andβ-CD was the second optimum vector.β-CD was defined as the most ideal vector in SSF for the reason of costs and appearance of productions. The physical properties of the adsorbent were evaluated to better understand the adsorption process. The factors temperature, pH, time and medium were evaluated and the optimal conditions for Saccharomyces cerevisiae Y1N4 adsorption with vectors contained temperature of 25℃, pH of 6.5, adsorption time of 12h and medium of 0.01M CaSO4,β-CD adsorption ability of 8.2 X 106 CFU/g can be achieved.
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