The Rules Of Quality Change In Braised Chicken During Processing Procedures

Braised chicken is a well-known traditional meat product and is popular with consumers. The characteristics of it is full of nutrient and flavor, and smooth taste which cooked with braised in traditional bittern called “laotang”. In this research, the changes of nutrient, flavor, texture of chicken and bittern during processing of braised chicken had been researched. The main contents and results were listed as follows:(1) The measurement of nutrition change in braised chicken and bittern at different stages of processing showed that: the sodium chloride, fat, protein content and pH in the chicken increased significantly(P<0.05) during processing. However, the production rate and moisture content decreased significantly(P<0.05). Total sugar content in products had no significant difference with carcass chicken during processing(P>0.05). The sodium chloride content and pH of bittern decreased significantly(P<0.05), and the moisture content increased obviously(P<0.05). there was no significant difference in other indicators(P>0.05). Heating “luzhu” was the most effective factor on chicken and each nutrition compounds went to balance after cooling “menzhu”.(2) The nucleotide and free amino acids compounds of braised chicken were analysed at different processing stage in this chapter. The taste effect and the umami intensity of taste compounds were evaluated by EUC and TAV. The electronic tongue was used as explained the change of different sensor indicator. The volatile flavor in braised chicken were analysised by SPME-GC-MS and OAV. The results showed that flavor nucleotide(5’-IMP, 5’-GMP, AMP) in chicken increased significantly(P<0.05) and I decreased significantly during processing(P<0.05). Hx and 5’-ADP had no significant difference(P>0.05). Free amino acids content decreased significantly(P<0.05). The flavor nucleotide, Hx and I decreased obviously of bittern during processing(P<0.05). However other nucleotide had no significant change(P>0.05). And free amino acids content increasing significantly(P<0.05). 5’-IMP, Glu and Lys played an important contribution to the taste of braised chicken as the TAV greater than 1. The EUC of braised chcken decreased significantly(P<0.05) and the products was full of umami which the content of 4.89 g MSG/100 g. Taste of saltness and umami increased significantly during processing(P<0.05), while bitterness and bitter aftertaste decreased significantly(P<0.05). Other taste changes were not obviously(P>0.05). High temperature “menzhu” and cooling “menzhu” were the key stage processing of braised chicken flavor formation. There were 54 species volatile flavor substances in braised chicken products. The greatest contribution of braised chicken volatile flavor were trans,trans-2,4-decadienal, nonanal, 4-methoxy- benzaldehyde, pentanal, eugenol, isoeugenol, and estragole as the OAV were greater than 1.(3) Tenderness, water holding capacity, microstructure and myofibrillar proteins degradation of braised chicken were analysis to explored the changes rules of texture feature during processing. Test results showed: the shear force and water holding capacity of braised chicken decreased significantly during processing(P<0.05). Pressurized water loss rate decreased significantly(P<0.05) during processing and stabilized in cooling “menzhu” processing. The change of fibre diameter was same as the shear force, and highest after warming “luzhu”. The tenderness of leg was better than breast as the fibre diameter finer than breast and denser than breast. Braised chicken microstructure changed significantly at different processing stage. The endomysium and perimysium of muscle fiber bundles condensed in primary processing. It began to appear granulated of muscle fiber bundles surface in “luzhu” processing, damaged gradually and the distance between muscle fibers went smaller in “menzhu” processing. The myofibrillar protein of chicken degradated significantly in warming “luzhu” processing. Larger molecular weight such as myosin, α-actinin and titin degradated completely in this processing. Bands of actin of leg and breast degradated as smalle peptieds and amino acids in high temperature “menzhu” and constant temperature “luzhu”.