Duck Intramuscular Phospholipase Simulation Reaction System And Its Test Method Research

Dry-cured duck, as one of the China’s peculiar dry-cured products, is favored by many people for its unique flavor. The flavor of foods, primarily containing aroma and savor, is a combination of gustation and olfactory sensations. The flavor of dry-cured meat is more dependent on the aroma, which is mainly composed of volatile flavor compounds. The flavor compounds of dry-cured meat are diverse, including alkanes, aromatic hydrocarbons, alcohols, These flavor substances come from the enzymatic and non-enzymatic changes of flavor precursors comprised of proteins, lipids, carbohydrates etc. Phospholipids are widely considered as main flavor precursor of cured meat. The flavor of dry-cured meat is relevant to the degradation lipids especially phospholipids, which is confirmed by many scholars at home and abroad. The changes of phospholipids are related to phospholipase and lipase. To extract the phospholipase and lipase from duck, our first concern is to remove other proteins from the duck meat; the second is to track the activity and reaction products of lipase and phospholipase. In this study, duck meat was used as the raw material, the optimal reaction system of phospholipid and the optimal enzymatic reaction conditions for phospholipid, the identification of phospholipid hydrolysates were carried out assisted with Thin Layer Chromatography (TLC) and to set up a technical method for the mechanism of phospholipid hydrolysis. A total of three sections are included in this study, the details are as follows:1Selection of the reaction system for phosphatidylcholineThe study established the optimal reaction system by comparing the micro-emulsion of phosphatidylcholine and the liposome of phosphatidylcholine. The results showed that starting from n-butanol, with the extension of the carbon chain, the area of micro-emulsion formed decreased. With respect to the n-butanol W/O micro-emulsion and n-propanol W/O micro-emulsion system, with the extension of the carbon chain, the hydrophobicity become stronger and the formation area of micro-emulsion become larger. In addition, Comparison of n-propanol W/O micro-emulsion and n-propanol O/W micro-emulsion system showed that n-propanol W/O micro-emulsion can provide more interfacial area to facilitate the enzymatic reaction. However, with a result of low enzyme activity and the impact of organic solvents on TLC, phosphatidylcholine liposome facilitate the enzymatic reaction than n-butanol W/O micro-emulsion. The results suggest that the best reaction system is the phosphatidylcholine liposome system.2Detection of intramuscular phospholipids hydrolysates of duck by TLCThis study investigated the detection of intramuscular phospholipids hydrolysates of duck by TLC and Quantity One. It used developing solvent of TLC by chloroform:methanol: water:triethylamine=65:25:3:0.2. The method is simple, fast and accurate, so it can used as a quickly preliminary test of intramuscular phospholipids hydrolysates.3Optimization of hydrolysis conditions for intramuscular phospholipids of duckThis study investigated the impact of enzyme and substrate ratio, temperature, time, and ultrasonic power on enzymatic hydrolysis of intramuscular phospholipid of duck. Through orthogonal experiments, the optimal conditions for enzymatic hydrolysis of phospholipids were determined. The results displayed that with the increase of the enzyme and substrate ratio, the fatty acids contents produced from phospholipid hydrolysis had a significant increase (P<0.05). Below50℃, as the temperature increased, the fatty acids contents significantly increased (P<0.05); while at63℃, the fatty acids contents significantly reduced (P<0.05). As the ultrasonic power increased, the fatty acids contents had no evident changes (P>0.05). As the time increased, the fatty acids contents had no evident changes (P>0.05).The factors impact the phospholipid hydrolysis in the descending order is:the enzyme and substrate ratio, ultrasonic power, ultrasound frequency, and temperature. The results showed that the best conditions of phospholipid hydrolysis is at the enzyme and substrate ratio of4, temperature of45℃, ultrasonic frequency of45KHz, ultrasonic power of270W, reaction time of0.5h.Taken all these results together, phospholipid reaction system is liposomes; the optimal reaction conditions of phospholipid hydrolysis is at the enzyme and substrate ratio of4, temperature of45℃, ultrasonic frequency of45KHz, ultrasonic power of270W, reaction time of0.5h. Meanwhile, the quickly preliminary analysis of the phospholipid hydrolysates by TLC is established.