Effects Of Ultrasound-Assisted Heating On The Nutritional And Texture Properties Of Pork Belly

As a raw material of famous dishes, pork belly is widely used in China. Boiling is a traditional heating method to cook meat, also it is an important process of meat manufacture. It was investigated that the application of ultrasound can promote salt permeation, extend shelf life, reduce the use level of salt and loss of cooking. The application of ultrasound shows great application prospect. The paper utilized ultrasound-assisted boiling to study the effects of ultrasound to protein,fat and flavor substance on pork and to provide theory for meat product modernization improvement. The research results are as follows:(1) The influence of ultrasound-assisted boiling to muscles protein of pork belly: it was revealed that,compared to traditional heated pork, ultrasound decreased nitrogen, improved the content of peptides of meat, the content of peptides of ultrasound group is 0.26mg/mL in 7.5 min which is higher than traditional group significantly. Ultrasound improved the content of free amido acid,in 60min, the free amino acid of ultrasound group improved 46%,. The result of SDS-PAGE showed the protain band was more narrow than traditional group and its color is lighter. Ultrasound accelerated the degeneration of pork protein.(2) The results showed that fat content of ultrasonic-assisted stewing one lower than the raw material by 13.32% and significantly lower than traditional stewing (p<0.05). During ultrasonic stewing, TBARS of meat increased(p<0.05). Ultrasonic-assisted boiling(120min) induced significantly lower polyunsaturated fatty acid(PUFA) and higher saturated fatty acid(SFA)(p<0.05). Ultrasonic-assisted boiling for 30min makes monounsaturated fatty acid(MUFA) content higher(p<0.05).(3) The flavor substances of the two kinds of cooked pork belly were tested and identified a total of 15 kinds of flavor substances. The flavor types of traditional cooked pork belly (13 kinds) was higher than that of ultrasonic cooked pork belly (9 kinds). Ultrasonic inhibits the formation of esters flavor substances, but the aldehyde content of ultrasound group is more than traditional group by 87.4% as high as 332.29 AU×106/g, nonyl aldehyde of traditional group account for 75.6% of ultrasound group, the limonene content of ultrasound is 14.01 AU×106/g. Aldehyde, limonene flavor substances content which contributes more in pork flavor were higher than the traditional group, ultrasound assisted cooking promoted the formation of fatty pork cooked meat aroma.(4) On the research of the effects of ultrasound on pork belly muscle layer heating, it was revealed that in the early part of the water bath heating,ultrasonic processing reduced the cohesiveness and adhesiveness of specimens;For fat layer of pork belly, ultrasonic treatment significantly reduced the chewiness of specimens.