Effects Of Different Processing Methods On Lipid In Pork

Pork consumption ranks first in meat consumption.Pork processed by different processing methods will undergo different changes in its lipids,which will have different effects on digestion and absorption.In this paper,the longissimus dorsi muscle is used as the study object,through four common processing methods:steaming,cooking,microwave and grilling,to explore the impact of pork lipids and volatile components,and further study of human liver cell activity And the influence of apoptosis in order to find a suitable processing method for pork,the main research contents and results are as follows:1.Using gas chromatography,the C₁₃ internal standard was used to quantify the fatty acid composition of total lipids,triglycerides,and phospholipids of pork lipids in four processing methods.The experimental results showed that there was no significant effect on the total fatty acid content of triglyceride compared to the four processings of the raw material group,which was approximately 68g/100g.Steaming,microwave and cooking had no obvious effect on the fatty acid composition of triglyceride;during baking,there were more changes in fatty acid content,and the contents of SFA and TFA increased with the increase of baking time,while MUFA and The PUFA content gradually decreases with the baking time.The four processing methods have different degrees of influence on the fatty acid composition of phospholipids.The baking has a greater influence on the composition of phospholipids,followed by cooking and microwaves,and the steaming has no obvious effect;during the cooking,microwave and baking process,the phospholipids The proportions of SFA and TFA increased with the increase of processing time,while the proportion of MUFA and PUFA decreased with the increase of processing time.Steaming had no significant effect on the total fatty acid composition of pork fat;both microwave and cooking reduced the PUFA content significantly;baking had a greater effect on total fatty acid composition than other processing methods.2.The content of phospholipid components in pork phospholipids?g/100g fat?in four kinds of processed pork phospholipids was quantified by HPLC column separation by high performance liquid chromatography and detection by evaporative light scattering detector.The results showed that three phospholipids were isolated,PC,PE and SM respectively.The effect of steaming on the components of pork phospholipid was less,but only PE decreased in the process of steaming.Microwave and cooking made the three components of phospholipid significantly reduced;the effect of baking on the content of phospholipid was the most,and the three components of phospholipid had the most reduction.In the process of steaming,cooking and roasting,the components of phospholipids first decreased rapidly,then gradually decreased with the extension of processing time.3.The effects of four processing methods on lipid oxidation of pork were determined by determining POV value,TBA value and AV value.All four treatments will promote the lipid oxidation of pork.Compared with raw meat,the POV,TBA and AV values of cooked pork are all significantly increased?P<0.05?.The POV values of steaming,microwave,and cooking gradually increased with the processing time;the POV value of baking increased first and then decreased with the increase of processing time.Compared with the raw material group,the TBA value of pork was significantly increased by cooking treatment?P<0.05?.The increase in the value of TBA for baking was most pronounced,followed by microwave and steaming,and the TBA value for cooking was the lowest.The AV value of cooked pork was significantly increased?P<0.05?,and the AV value gradually increased with the processing time.The AV value of the grill is the largest,followed by the microwave and cooking,and the steamed AV value is the smallest.4.The volatile components of pork were determined by solid-phase microextraction and gas chromatography-mass spectrometry.The single-factor method was used to optimize the sample size,equilibrium time,extraction temperature,extraction time and resolution time of solid-phase microextraction.The results showed that the optimum conditions after optimization of SPME were:Weigh3g pork in 20ml extraction bottle,equilibration time 30min,extraction temperature80°C,extraction time 30 min,resolution time 4 min.Twenty-two kinds of volatile components including aldehydes,heterocycles,alcohols and hydrocarbons were separated and identified from the processed pork by gas chromatography-mass spectrometry.The most volatile components were produced by baking.The content of aldehydes in the 22 volatile components was the highest,accounting for77.48%⁸8.12%,followed by heterocyclic compounds and alcohols,accounting for about 8.59%¹3.93%and 5.69%¹0.84%respectively.The lowest content of hydrocarbons was hydrocarbons,about 0%¹.9%.There are significant differences in some of the volatile components corresponding to the four cooking methods.5.Through MTT experiment and flow experiment,the effects of different processing methods on the lipid of pork in normal liver cells were discussed.MTT results showed that the cell viability of the four processed pork treated with lipid decreased with the increase of lipid concentration.At low concentration of lipid?0.01mg/m L?,the steamed lipid has no obvious effect on cell viability.Microwave and boiling lipid have certain inhibitory effects on cell viability,and the inhibition of lipid on cell viability is the most obvious.The effect of lipid on cells?4.00mg/mL?,the inhibition of steaming and microwave lipid on cell viability was smaller than that in cooking and baking,and the inhibition of baking was the most obvious.When the high concentration of lipid is acting on the cell?8.00mg/m L?,the survival rate of the cells corresponding to the steamed lipid is the largest,followed by the microwave and the boiled lipid,and the survival rate of the roasted cells is the smallest.The results of flow cytometry showed that the total apoptotic rate of the four lipid treated cells increased significantly,and the apoptotic rate increased with the increase of lipid concentration.When the lipid concentration was 0.05mg/mL,the rate of apoptosis was lowest,followed by microwave and cooking.When the lipid concentration was4.00mg/m L,the total apoptosis rate of the steamed group was 22.87%,the microwave group was 31.70%,the boiling group was 33.20%,the roasting group was 19.29%,but the number of dead cells in the roast group was more than the other groups,the number of dead cells in the roasting group was 13.90%,and the other groups were less than 4%.This may be because the concentration of the baked lipid is more than4%.At large,cell death was caused directly.