Forming Factors Of Minced Mutton Gel Induced By Dense Phase CO2 And The Primary Investigation Of Its Mechanism

Dense-phase CO₂ (DPCD) processing technology is a new type of non-thermal processing technology. Compared to traditional thermal processing technology, it has the advantage of low heating temperature, good effect of sterilization, and little harm to nutrition and so on. In recent years, the study of DPCD processing technology is growing. During the early using DPCD as sterilization in the laboratory, we found that DPCD can induce the formation of gel structure. And the property of gel is one of the most functional characteristics of meats .It can not only affect product texture and sensory characteristics, but also influence the production rates.So this paper took the minced mutton as the object, studied the forming factors of gels induced by DPCD and then did the primary investigation of its mechanism, which provided a theoretical basis for using the DPCD in the meat processing. Specific studies results are as follows:(1) The influence of DPCD on the gel properties of minced mutton compared to heat-induced gel was studied by means of the gel color, pH values, water hold capacity, texture properties and microstructure. The results showed that minced mutton can form denser gel induced by DPCD than heating.The color, hardness, springiness, cohesiveness and chewiness of gel induced by DPCD had greatly improved, but pH values did not change significantly and the water holding capacity slightly went down compared to heat-induced gel. It was found that too high or too low pressure wasn't suitable to form the gel induced by DPCD according to the SEM. So we should choose the suitable conditions of DPCD to form the gel.(2) By adding different content of compound phosphates, the influence of formation of gel induced by DPCD was studied.The results showed that compound phosphates can promote the formation of gel induced by DPCD. With the addition of phosphates increasing, pH values, water holding capacity, hardness, springiness, cohesiveness and chewiness of DPCD-induced gel increased significantly, and the structure became more compact. Meanwhile, the addition of phosphates was not good for the color of the gel.With the addition of compound phosphates increasing, the L*, a* and b* values decreased in different extent.So we should choose the right adding content of compound phosphates.(3) Myosin was extracted and purified by DEAE-52 cellulose ion exchange chromatography and polyacrylamide gel electrophoresis (SDS-PAGE), and then use Fourier transform infrared spectroscopy (FTIR) and circular dichroism (CD) spectroscopy to study the changes of secondary structure of myosin after treating by DPCD. The results showed that myosin had three chains: molecular weight was 25.9, 17.2 and 13.0 KDa. The content ofβ-sheets increased significantly with the increase of pressure, but the increment became slightly above 30MPa. And the contents ofα-helix,β-turns and random coil decreased with the increment of pressure, they trended to convert to theβ-sheets.