Study On The Processing Technology And Quality Characteristics Of Tea Oil Cheese Rich In Unsaturated Fatty Acid

Mold cheese is rich in nutrients,with a lipid content of about 30%,but in its fatty acid composition,saturated fatty acids account for about 70%,and it lacks unsaturated fatty acids（UFAs）.Mold starter plays a key role in the production of mold cheese and has a significant impact on the quality characteristics of cheese,but most cheese starters lack the ability to convert unsaturated fatty acids.It is of great significance and application value to introduce tea oil to increase the substrate availability of fermented strains and further increase the ratio of UFAs to saturated fatty acids.Tea oil cheese is a new type of mold cheese that uses Actinomucor elegans（A.elegans）to participate in the cheese fermentation process,and adds tea oil for fatty acid blending and UFAs for maturation.A.elegans is a kind of mold commonly used in the production of fermented bean curd in my country.Its UFA conversion rate is 8.1%.It can be used as a cheese starter to increase its UFA content,and also help cheese to form a unique taste and characteristic flavor.In this study,the strains used in fermented cheese were initially screened for high-yield UFAs and the culture conditions were optimized,and the process of cheese processing was optimized.Increase UFAs in cheese to address the lack of high-potency UFAs transformants in mold cheese starters and UFAs in mold cheese.In this paper,A.elegans with high UFA production was preliminarily screened by the fatty acid synthase inhibitor-cerulenin;the conditions required for A.elegans to produce UFAs in the culture process,the conditions of cheese curdling and the processing technology of UFAs conversion were optimized;The nutritional components and physicochemical indexes,organoleptic properties,texture properties and taste characteristics,fatty acid composition and volatile flavor substances of camellia oil-ripened cheese under optimal process conditions during the ripening period,provide the basis for the production of tea oil-rich cheese with UFAs.Theoretical basis.The main results are as follows:1.Screening of Mucor elegans and study of its fatty acid conversion performance:4.48×10^-7mol/L Cerulenin and 0.05%2,3,5-Triphenyltetrazolium chloride（TTC）were used to determine the growth state of A.elegans mother liquor concentration,screened out A.elegans with high UFA production,and improved the ability of A.elegans to synthesize UFAs by replacing the carbon source in the PDA medium;and determined the carbon source The biomass and fatty acid production of A.elegans after replacement culture were increased to 12.79±2.76 g/L,and the total content of UFAs was increased to 10.45%.2.Optimization of conditions for the conversion of fatty acids by Mucor elegans:A single factor experiment was conducted with p H value,culture temperature,culture time and carbon source concentration to investigate the effects of different culture conditions on the UFAs transformation ability of A.elegans.On this basis,the orthogonal experiment was designed by means of culture temperature,culture time and carbon source concentration,and the optimal conditions for A.elegans to synthesize UFAs were determined as follows:culture temperature of 28°C,culture time of 72 h,and carbon source concentration of 4.5%.Under these conditions,A.elegans had the strongest fatty acid conversion ability,and the UFA content was 12.36%.3.Optimization of tea oil cheese processing technology:A.elegans strain with high UFAs transformation ability was used as a starter to make mold cheese,and the curd effect was determined by the addition of saturated Ca Cl₂,the addition of rennet,the healing time and the addition of lactic acid bacteria.The score was used as the index,and the single factor experiment and the design of the orthogonal experiment were carried out to determine the optimal process parameters of the cheese during the curdling process:the addition of saturated Ca Cl₂was 0.015%,the addition of rennet was 0.15%,the healing time was 11 min,and the addition of lactic acid bacteria was 0.80%,the cheese curd effect score was 93.2 points.Through the fermentation time,the amount of bacteria inoculated,the amount of sugar added and the fermentation temperature,with the UFAs content in the cheese as an index,a single factor experiment and an orthogonal experiment were designed to determine the optimal process parameters of the cheese fermentation process:A.elegans inoculation The total content of unsaturated fatty acids in this cheese was 44.45%,with a fermentation temperature of 0.70%,a fermentation temperature of 28°C,a fermentation time of 7 d,and the addition of white sugar 2%.4.Study on the quality characteristics of camellia oil cheese during ripening:During the ripening period,the nutritional components and physicochemical indexes,sensory characteristics,texture characteristics and taste characteristics,types and contents of fatty acids and Changes in volatile flavor content.The results showed that the moisture content,fat content and p H value of the two groups of cheeses all showed a downward trend during the maturity period;Has the highest sensory acceptance.During the ripening period,the hardness,elasticity and chewiness of camellia oil-ripened cheese showed a downward trend,while the cohesiveness showed an upward trend.The most significant change in the taste of cheese during the ripening process is the sour taste.The fatty acid changes of cheese were the most significant at 9 days of ripening,mainly containing 9 kinds of fatty acids,and the highest content of unsaturated fatty acids in cheese was 7.04g/100g.With the prolongation of maturation time,the total amount of UFAs in camellia oil mature cheese showed an upward trend,of which the content of oleic acid increased by 7.60%,and the content of linoleic acid increased by 2.90%.The content of acid and linoleic acid showed an upward trend.A total of 46 flavor substances were detected in the maturation process of camellia oil mature cheese,and the flavor substances were the most abundant when matured for 6 days,including 9 kinds of acids,14 kinds of esters,6 kinds of aldehydes,6 kinds of alcohols,7kinds of ketones and 3 kinds of alkanes;33 kinds of volatile flavor substances were detected during the ripening process of mold cheese,and the flavor substances were the most abundant at 6 days of ripening,including 8 kinds of acids,8 kinds of esters,5 kinds of volatile flavors.aldehydes,4 alcohols,and 6 ketones.To sum up,the environmental conditions required for the metabolism of UFAs by A.elegans were studied,the content of UFAs converted by A.elegans during the cheese fermentation process was increased,and the loose texture of the finished cheese caused by the unstable curdling effect in the early stage of cheese production was improved.