| The sauce duck products are mainly concentrated in Jiangsu and Zhejiang provinces in China. At present, the kind of sauce duck is small, the equipment is poor, moisture content is high and low degree of standardization, which cause the sauce duck cannot adjust circulation pattern and restrained the flavor quality of the final products. This study use sauce-cured and intensifying high temperature dry-airing process to make sauce duck. The present study invested the effect of intensifying high temperature process combined with dry-ripening on lipid hydrolysis and oxidation and sensory quality. Based on the lipolysis-oxidation indices, an orthogonal array design matrix was considered to optimize the processing condition during the different processing stages. The detailed contents are as follows:1. Study on the optimization of intensifying high temperature air-drying maturation processing of sauce duckIn order to investigate the optimal processing of sauce duck, orthogonal experiments were used to explore amounts of salt, air-drying temperature and time on the TBARs and sensory quality. Results indicated that the optimal processing of sauce duck was air-drying temperature,24℃-28℃-32℃, air-drying time,60h and9%salt(m/m) by wet-salting method for24h and scored the highest sensory score. The POV(0.08g/100g) and TBARs(0.13g/100g) of its group was decreased by66.67%and45.83%to low temperature(16℃-20℃-24℃), which was consistent with sensory score. It showed that high temperature can decrease lipolysis-oxidation indices and enhance sensory quality.2. Effect of intensifying high temperature process on lipid hydrolysis and oxidation during processingThe effects of intensifying high-temperature air-drying ripening process on lipid hydrolysis and oxidation were investigated by analyzing TBARs and POV of brisket and subcutaneous lipid and activity changes of lipolytic enzymes and lipoxygenase during air-drying process. The result shows that the activity of lipoxygenase, acid lipase, phospholipase and neutral lipase increased separately by51.32%,38.21%,23.60%and7.49%and which was always larger than the control group. In contrast with control group, the POV (0.11g/100g,0.13g/100g) and TBARs(0.10mg/100g,0.09mg/100g) of brisket and subcutaneous lipid was decreased by15.38%,18.70%and28.57%,18.18%after60h air-drying. It showed that intensifying high temperature can improve the activity of enzymes and decrease lipolysis-oxidation indices.3. Effect of intensifying high temperature process on flavor during processingThe effects of intensifying high-temperature air-drying ripening process on flavor quality during processing. Flavor compounds in the brisket were extracted and identified by SPME-GC-MS system using the samples mentioned above. The flavor compounds in sauce duck could be clustered in the following chemical families:hydrocarbons, alcohols, aldehydes, ketones, carboxylic acids, esters, nitrogenous compounds, furan, which showed different changing rules during processing of sauce duck. Generally, in the brisket, the contents of aldehydes and alcohol and ketones showed increasing tendency, the content of carboxylic and esters and hydrocarbons decreased; furan and nitrogenous compounds formed and increased first then decreased during processing. In the final product of sauce duck, the contents of aldehydes, carboxylic acids, alcohols and ketones in brisket were70.86%,1.51%,12.01%and7.71%, hexanal was59.83%. Compared to the control group, the aldehydes and ketones of the group with high temperature was decreased by2.48%and0.19%, alcohol and hydrocarbons was increased by1.56%and0.57%. It showed that aldehyde was the key to the flavor of sauce duck, which came from decomposition and oxidation of lipid, hexanal was the most important to sauce duck oxided from linoleic acid. |
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