| In this paper, Sichuan sausages were regarded as research object, the subcutaneous fat of raw meat were dealt with different temperatures and the difference was statistically significant(p<0.05). According to the different oxidized levels from low to high, four groups were marked as group A,group B, group C and group D, respectively. Then the oxidized subcutaneous fat and lean meat, spices mixed together into Sichuan-style sausage. Changes in physical and chemical properties, lipid oxidation and degradation, protein oxidation and proteolysis, and sensory characteristics were investigated. The aim was to provide a certain theoretical for Sichuan-style sausage quality improvement. The main results and conclusions were as follows:(1) The results of physical and chemical properties in Sichuan sausage during ripening with different treatmentsindicated that:the moisture content, Aw exhibited decrease during ripening and showed D>C>B>A. While the result of pH were on the contrary. The results showed that the value of moisture content and Aw increased, but the value of pH decreased in Sichuan sausage with the degree of oxidized lipid.(2) Peroxide value in Sichuan sausage which was made by different levels of oxidized lipid did not change regularity during ripening. TBA value showed D>C>B>Aafter stored 45 days. The change of neutral lipid was not significant during ripening, however, the content of monounsaturated (MUFA) and polyunsaturaten (PUFA) in phospholipid decreased with the extension of sausage ripening time, and different treatments showed a certain regularity, which was A>B>C>D. The content of free fatty acids had a rising trend in the early period of ripening, then decreased, group C and D had a more obviously change than group A and B. The phospholipids were equivalent to release free fatty acids, and the rate of release of unsaturated fatty acids was higher than saturated fatty acids.(3) The effect of total nitrogen in Sichuan sausages during ripening with different treatments had little effect (p>0.05), however, the oxidized lipid had a great effect on nonprotein nitrogen and free amino acid, especiallyin the later ripening each treatments had obviously change, D>C>B>A. Meanwhile, SDS-PAGE results also indicated that the changes of myofibrillar protein in group C and D were more fiercely than group A and B. These results showed the oxidized lipid caused structural changes of protein, which caused the occurrence of protein degradation in return. There was some interaction between protein oxidation induced by oxidized lipid and protein degradation.(4) The carbonyl content of sarcoplasmic proteins and myofibrillar protein presented an upward trend firstly then downward with different treatments, then showed a certain regularity in later ripening period. The value of S-S and protein surface hydrophobicity of sarcoplasmic and myofibrillar proteins had a similar variation. In addition, the change degree of myofibrillar protein was higher than that of sarcoplasmic protein, and the results of each groups showed D>C>B>A. Due to adjacent sulphur crosslinking form disulfide bond with each other, so the change trend of sulpher content in contrast to the results of disulfide. A series indicators of protein oxidation indicated that the oxidized lipid caused the protein oxidation, and the degree of protein oxidation was determined by oxidized lipid, then changed protein structure and leaded to the aggregation of protein molecules.(5) The results of sensory score with different treatments indicated that the highest score was group C, using electronic senses for auxiliary experiment found that electronic senses had a higher sensitivity than human sensory. The results of colour showed that L value and b* value presented a regularity change in later ripening period, which was A>B>C>D, while a* value changed opposite.The results of TPA observed the changes of hardness, gumminess, chewiness and springiness in consistency, the overall varity showed D>C>B>A. The volatile compounds of Sichuan sausage at different stages of ripening were analyzed by gas chromatography/mass spectrometry (GC/MS) with solid-phase microextraction (SPME). Seventy one volatile compounds were identified. Aliphatic hydrocarbon, alcohols and esters were the most important chemicals in all the samples, respectively. The contents of aldehydes compounds increased in early period and then decreased with different treatments. Any change in protein conformation of physical and chemical factors, not only affects color and texture of sausage also affcets the role of proteins, peptides and volatile components, thereby affecting the flavor quality of Sichuan sausage. |
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