Effect Of Intensifying High-Temperature Drying-Ripening Process On Lipolysis And Lipid Oxidation And Quality Flavor Of Chinese Bacon

Bacon is representative of the traditional cured meat products favored by consumers because of its unique flavor. The lipolysis and lipid oxidation process in cured meat was not only the necessary pathways to flavor formation, but also the important factors to affect the quality and flavor. Chinese bacon experienced a strong decomposition and oxidation in the curing, drying, fermentation maturation process, affected by a variety of factors such as salt content, process time, drying-ripening temperature, endogenous enzyme activity, microbial and ultimately its independent flavor characteristics formed. The temperature of drying-ripening has an important impact on lipolysis oxidation and flavor quality.Intensifying high-temperature can accelerate lipolysis, lipid oxidation and formation of flavor, reducing lipid oxidation index. This test was a further research on the basis of our laboratory, designed to explore the effects of intensifying high-temperature process on lipolysis oxidation and flavor quality which provided experimental and theoretical basis to control lipolysis, lipid oxidation and accelerate the formation of flavor quality. The specific contents and results are as follows:1. Effect of intensifying high-temerature drying-ripening process on lipolysis and lipid oxidation of Chinese baconDry-cured bacons were processed using pig bacon belly as material by dry-salting for three days, intensifying high-temperature drying-ripening at65℃for0.5h, then air-drying mature for eight days. The study was aimed to reveal effects of intensifying high temperature ripening on lipolysis and lipid oxidation in Chinese bacon through analyzing changes of lipase, lipoxygenase activity, free fatty acid and TBARs value and POV in muscle. The results showed that:compared with control group, the treatment of65℃intensifying high temperature ripening strengthen the neutral esterase, acid esterase and pHospHolipase activity increased by30.65%,63.64%and87.10%respectively.LOX activity increased of73.42%(P<0.05) and at the after pHase they were higher all the time; four main free fatty acid concentrations were increased in different degrees, in which PUFA linoleic content increased by41.73%(P<0.01), but it was decreased32.84%than the control group at the end of processing; TBARs values and POV of lipid oxidation Index decreased by26.10%and45.00%(P<0.05) respectively at the same time. It was explained that intensifying high-temerature drying-ripening process could significantly improve lipase and lipoxygenase activity, accelerate lipolysis which made FFA and especially USFA increase significantly,, and high-temperature promote further lipid oxidation at the late of drying-ripening lead to USFA decrease significantly and generate more small flavor compounds. At the same time, both POV and TBARs values were effectively reduced in the finial product to improve the safety.2. Optimization of intensifying high-temperature drying-ripening process of Chinese baconSingle factor test was done using temperature of intersifying high-temperature as the facter of experiment to determine the best temperature.The orthogonal array design method was used to study the effects of intensifying high-temperature temperature, dry-ripening temperature and dry-ripening time on the sensory quality and lipid oxidation of meat products. The analysis showed that TBARs value was correlated with strengthen temperature significantly positively, and was negatively correlated with the drying-ripening temperature (P<0.05); POV had a significant positive correlation with intensifying high-temperature temperature(P<0.05), and had a negative correlation significantly with drying-ripening temperature(P<0.01). Intensifying high-temperature temperature had significant interaction on TBARs values with drying-ripening temperature and drying-ripening time. The intensifying high-temperature temperature critical value increased linearly with drying-ripening temperature increasing,and decreased linearly with drying-ripeningtime increasing.The way of shortening appropriately the process time and increasing drying-ripening temperature could reduce the TBARs value and POV in the final product. The optimum process conditions obtained by regression optimization for maximizing sensory score and minimizing TBARs value were as follows:intensifying temperature65℃, drying temperature18-29.5℃, relative humidity72%-68.5%and drying time8d. The dry-cured product obtained under these conditions contained3.56%of salt and52.2%of moisture and scored the highest in good agreement with sensory analysis.3. Effect of intensifying hightemperature ripening maturation on quality and flavor of Chinese baconChinese bacon’s pHysical and chemical indicators (moisture content, salt content, the weight loss rate pH value),color, shear force, texture, sensory score and flavor compounds were determinated in the process of intensifying high-temperature ripening. The effects of the intensifying high-temperature process on quality and flavor were studied, compared with traditional process. The results showed that:the ntensifying high-temperature had significant effects on the indicators above and bonding and chewing were increased in good agreement with sensory score. Chinese bacon was detected to have52volatile flavor compounds, including five categories of11aldehydes,16alcohols,7ketones,8esters and10hydrocarbons. Hexanal, benzaldehyde, heptanal,1-octen-3-alcohol,2-simenol,2-heptanone and ethyl acetate were more, which may be the characteristic flavor substances of product.The volatile flavor compounds were increased by6species than the control group in the product, in which there were significant increase on the type and quantity of the important flavor compounds including saturated aldehydes, unsaturated alcohols. It was explained that intensifying high-temperature process had an important contribution to the flavor of Chinese bacon.