Study On The Preparation And Composition Characteristics Of Polypeptides And Polysaccharides From Camellia Oleifera Meal

Camellia oleifera meal is a by-product produced by the pressing of Camellia oleifera seeds,a characteristic oilseed crop in China,and is rich in protein and sugars.With the development of camellia oleifera seed processing industry,the output of camellia oleifera meal has surged,however,its processing technology is relatively backward,resulting in a significant waste of resources.Therefore,in order to increase the utilization value of oilseed meal,this paper aims at improving the extraction rate of polypeptides and polysaccharides in camellia oleifera meal by optimizing the process,adopting new methods to achieve the co extraction of polypeptides and polysaccharides,and studying its functional characteristics to obtain high-quality camellia oleifera meal polysaccharides and polypeptide extraction technology,providing theoretical guidance for the development and utilization of camellia oleifera meal.The main findings are as follows:First,using cold-pressed camellia oleifera meal as raw material,a combinatio n of single-factor experiments and Box-Behnken response surface methodology was used to optimise the extraction of peptides from oil tea meal by a combination of alkali-soluble acid precipitation and enzymatic methods.Taking the extraction rate of polypeptides as the target,by optimising the amount of enzyme added,enzymatic digestion temperature,and digestion time,the optimal extraction process was obtained as follows:enzyme addition amount of 8.0%,enzymatic hydrolysis temperature of 32.0℃,and the enzymatic digestion time is 5.0 hours.Under these conditions,the extraction rate of polypeptides from camellia oleifera meal was15.12%.The process of hot water extraction of polysaccharides from oil tea meal was optimised.Using the polysaccharide yield as the ta rget value,the optimum extraction process was obtained by optimising the material-to-liquid ratio,extraction time and extraction temperature.The optimal extraction process was as follows:material liquid ratio 1:31 g/m L,extraction time 102.0 minutes,and extraction temperature 71.0℃.Under these conditions,the yield of polysaccharides from camellia oleifera meal was 16.20%.Secondly,in order to achieve the common extraction of polypeptides and polysaccharides,the extraction rates of polypeptides,polysacch aride yields,and degree of hydrolysis of camellia oleifera meal extracted by four methods,namely,snail enzyme extraction alone,neutral protease extraction alone,snail enzyme and neutral protease compound extraction,and snail enzyme and neutral protease step-by-step extraction,were compared.The experimental results showed that the extraction of oil tea meal was best achieved by a stepwise extraction method using snail enzyme and neutral protease.Combined with single-factor orthogonal experiments,it was found that the optimal conditions for the co-extraction of peptides and polysaccharides was an enzymatic digestion temperature of 45.0°C,enzymatic hydrolysis p H of 8.0,enzymatic hydrolysis time of 120.0 min,snail enzyme addition amount of 50.0 mg/g,neutral protease enzymatic hydrolysis time of 90.0 min,and neutral protease addition amount of 60.0 mg/g.Under these conditions,the extraction rate of polypeptide from camellia oleifera meal was8.83%,and the yield of polysaccharide was 24.33%.Finally,the effects of different pretreatment methods on the functional characteristics of the co extraction of polypeptides and polysaccharides from camellia oleifera meal were studied.The water-holding capacity,oil-holding capacity,foaming capacity,foam stability,emulsification capacity and emulsion stability,ultraviolet,infrared,thermogravimetric analysis,antioxidant activity and other functional characteristics of the polypeptide and polysaccharide co extracts from camellia oleifera meal obtained by six differ ent pre-treatment methods,including non peeling cold pressing,peeling cold pressing,90.0℃peeling hot pressing,120.0℃peeling hot pressing,150.0℃peeling hot pressing,peeling extraction,were compared with the polypeptide and polysaccharide extracted separately.The experimental results show that,the comprehensive characteristics of the polypeptide and polysaccharide co extracts extracted from the camellia oleifera meal processed by the peeling and leaching method are the best.The peak weight loss temperature in thermogravimetric analysis was 163.55°C,and the remaining weight of thermogravimetric weight was 40.55%,which was a good overall performance;The total amino acid content was high(18.51 g/100g);The scavenging ability of ABTS free radicals(54.62%)and hydroxyl radicals(56.89%)were the highest;The water holding capacity(2.48 m L/g)and oil holding capacity(3.01 m L/g)were better.At 50.0℃,the foaming(79.80%),foam stability(99.30%)and emulsification(40.63 m~2/g)were the highest,and the emulsification stability was also good.In summary,in this thesis,the extraction conditions of polysaccharides and peptides in oil tea meal were optimized to improve the yield,and the technique of co-extraction of polysaccharides and peptides was developed,and the obtained polysaccharides and peptides have good functional properties,which provide theoretical support for industrial production.