Study On Rosin Residue In Waterfowl Carcass Defeathered By Rosin Glyceryl Ester

Rosin glyceride is the esterification product of rosin and glycerol,which is used as depilatory in the slaughter and processing of goose,after the depilation of rosin glyceride,free rosin remains in the carcass of goose,which has potential food safety risks.The purpose of this study is to study the residue of rosin glyceride in the carcass of meat geese with free rosin as the object.The specific research contents and results are as follows:1.Establishment and application of the method of free rosin in rosin glyceride.Using HPLC-PDA/FLR detection method,AA and DHAA were used as rosin residue markers to detect the contents of AA and DHAA in rosin glyceride.The mobile phase was 0.1% formic acid aqueous solution-acetonitrile(16: 84,v/v),and the retention times of AA and DHAA were 13.4 min and 9.0 min;respectively.The detection limits of AA and DHAA are 0.038 μg/g and 0.012μg/g respectively,and the quantitative limits are 0.127 μg/g and 0.040 μg/g respectively.The precisions of AA and DHAA are 1.19% and 2.05% respectively,and the recoveries of AA and DHAA are 82.3% ～ 85.4% and 81.0% ～ 85.5%respectively.The results show that the analytical method established in this study has good precision,recovery and sensitivity.All the food-grade rosin glycerides produced in different factories contain free rosin,with AA and DHAA contents of 2.10% ～ 2.96% and 0.29% ～ 0.73% respectively,and AA/DHAA ratio of 3.82～ 7.24.The experimental results showed that free rosin was detected in rosin glycerides on the market,and the contents of AA and DHAA in rosin glycerides from different factories were different.2.Effect of stability of rosin glyceride and depilation process on free rosin.(1)After storage at room temperature for 15,30 and 45 days,the AA content in rosin glyceride decreased by 16.9%,32.7% and 26.4% respectively.The results showed that the content of free rosin in rosin glyceride showed a downward trend in general under closed storage at room temperature.With the prolongation of hair removal time,AA content showed a downward trend,while DHAA content showed an upward trend,resulting in a downward trend in the ratio of AA to DHAA.(2)Heating temperature(120 ～ 200°C),heating time(0 ～ 8 h)and pollutants are the main inspection indexes of the simulated unhairing process.With the increase of heating temperature and heating time,the content of free rosin and DHAA increased as a whole,and the AA content fluctuated greatly,which led to the irregular change of AA/DHAA.Blood,fat and residual feathers are the main pollutants of rosin glyceride in hair removal process.The change of rosin content in the process of repeated use of rosin glyceride by three pollutants(0 ～ 30 times)was explored.The results show that organic pollutants and repeated heating times have great influence on the content of free rosin in rosin glyceride,and AA/DHAA changes irregularly because of the difference in AA production and consumption.3.Effect of depilation times of rosin glyceride on rosin residue in carcass epidermis and muscle tissue of meat goose.The effects of simulated depilation times of rosin glyceride on rosin residue in skin and muscle tissue of meat goose were studied.The results showed that the rosin residue in skin was higher than that in muscle tissue.Wing skin is the part with the highest rosin residue in epidermis,with the residue as high as 14.33 g/g,and the breast muscle part has the lowest content,with the minimum value of 1.25 g/g.With the increase of unhairing times,AA and DHAA in epidermis showed a downward trend as a whole.The contents of AA and DHAA were 1.58 ～ 12.57 g/g and 0.39 ～ 1.57 g/g respectively,and AA/DHAA was 2.54 ～ 7.13.The contents of AA and DHAA in muscle were 1.13 ～ 3.29 g/g and 0.11 ～ 0.34 g/g respectively,and AA/DHAA was 6.25 ～ 10.29.4.Analysis of rosin residues in meat goose products in circulation field.The positive detection rates of AA and DHAA in the meat goose products in the market were 81% and 71% respectively,and the residues of AA and DHAA in the actual samples were 0.64 ～ 14.52 g/g and 0.06 ～ 10.06 g/g,which indicated that rosin residues were common in the meat goose products in the market.In this study,the samples in which AA and DHAA were detected at the same time were analyzed.Among 21 samples,AA/DHAA of one sample was in the range of 5.34～ 27.32,AA/DHAA of three samples was in the range of 2.54 ～ 10.29,and AA/DHAA of 11 samples was lower than 2.54.The source of rosin residue can not be effectively distinguished,so AA/DHAA can be used to distinguish the source of free rosin residue in the epidermis of goose carcass.In this study,the rosin residue in the carcass of meat geese caused by depilation of rosin glyceride was studied,which provided technical support and guidance for the slaughter and processing enterprises regulated by the state and protected and promoted the food safety of consumers.