| Chicken gizzard is the gizzard of chicken,it is benefit for digesting food.Chicken gizzard is prone to oxidation during processing and storage,leading to spoilage and deterioration,reduced commercial value and nutrition.The myoglobin in chicken gizzards is a kind of heme protein,its oxidation is the primary cause of spoilage and deterioration of chicken gizzards.This article studies the purification methods and process parameters of chicken gizzard myoglobin and the influence of external conditions on the oxidation of myoglobin in different processing stages.Study the oxidative properties of myoglobin in chicken gizzards to provide a basis for the storage safety of chicken gizzards and chicken.The main methods and results of the research are as follows:(1)By comparing the myoglobin content in different muscle tissues of chicken,it was found that the myoglobin content in gizzard was 1.72 mg/m L,which was about 6 times that of chicken heart,10 times that of chicken leg and 100 times that of chicken breast.Finally,the gizzard was determined as raw material.(2)For sample pretreatment,different cleaning solutions,extracts,and cell disruption methods were used to compare the content of chicken gizzard myoglobin.The results showed that myoglobin in gizzard was washed with normal saline,extracted with sodium phosphate buffer solution,homogenized at 13000 rpm for 1min,and ultrasonicated at 750 w for 5min.The myoglobin content in gizzard was 1.72 mg/m L,and the relative purity was 16.46%.After separation by ammonium sulfate precipitation,the content of myoglobin in gizzard was 1.87 mg/m L,and the relative purity was 20.26%.(3)The process parameters of the extraction,separation and purification of myoglobin from chicken gizzard were optimized,and the optimal p H of the extract was 8.0,the extract concentration was 40mmol/L,and the ratio of material to liquid was 1: 1.5,standing time 0.5h,ammonium sulfate saturation 80%.A dialysis bag with a molecular weight cut-off of 7000 Da was selected to dialyze chicken gizzard myoglobin.The content of myoglobin after dialysis was 2.04 mg/m L,and the relative purity was 23.85%.The purified myoglobin chromatography packing Sephadex G-75 was selected,the sample volume was 1.5m L,and the elution flow rate was 0.4ml/min.Under these conditions,the purified myoglobin content was 2.53 mg/m L and the relative purity was 91.34%.(4)The purified product was scanned at 350-600 nm wavelength,which showed that there were characteristic peaks at 410 nm,540nm and 580 nm,and the purified product conformed to the characteristic absorption peak of myoglobin.SDS-PAGE electrophoresis showed that there was an obvious band at 17000 Da,which showed that myoglobin had a good purification effect with the separation and purification treatment.(5)The oxidation characteristics of purified myoglobin were studied,and the influence of external factors p H,salt concentration,heating temperature,storage time and storage temperature on the oxidation of myoglobin was analyzed.The results showed that as the p H value increased,the percentage of oxygenated myoglobin in the purified myoglobin increased and there was a significant difference(P<0.05).the effect of salt concentration on myoglobin oxidation was not obvious and there was no significant difference(P>0.05);the higher the heating temperature and the longer the storage time,the faster the myoglobin oxidation rate and there was a significant difference(P<0.05);the lower the storage temperature,the myoglobin oxidation rate decreases significantly and there was a significant difference (P<0.05). |
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