Extraction,Refining,Modification And Shortening Preparation Of Altay Big Tail Sheep Fat

The Altay Big Tail Sheep is a famous fat-type sheep in Xinjiang with excellent meat.It has local characteristics through herders working hard to graze.Altay large-tailed sheep has the characteristics of strong physique,tender meat and rich nutrition,and is deeply loved by local residents.At present,the mutton resources of Altay Big Tail sheep have been well developed and utilized,but the abundant sheep tail fat resources have not been well used.Moreover,the application of sheep tail resources is less,the production profit is low,and the purchase price is generally low,which cannot meet the demand of processing enterprises.Therefore,in order to make the abundant tails of Altay sheep efficiently and reasonably used,this study selected Altay sheep tail for extraction,refining and fractionation treatment,and then the fractionated products were compounded with vegetable oil and emulsifier.Finally,the compounded product is prepared into shortening.The research is mainly divided into the following aspects:1.By comparing the dry decoction method and the enzymatic method,and considering the test cost,operability,yield and other factors,the dry decoction method was selected as the extraction method for Altay sheep fat.The best extraction conditions were: heating temperature 90,heating time 50 min,centrifugation speed 4500 r / min,centrifugation time 20 min.With these conditions,the Altay sheep tail oil extraction rate could reach 74.25.Compared with other extraction methods,the extraction rate of sheep tail oil was improved,the test cost was lower,the operation was easier,and the quality of extracted sheep tail oil was better.2.Refining Test of Sheep Tail Oil(1)The factors and conditions affecting the degumming effect of extracted sheep tail oil were determined by single factor test and response surface optimization test.The results showed that the optimum degumming conditions were as follows: the best acid addition 4%,the best degumming temperature 95,the best degumming time 32 min and the degumming rate 83.63%.The sheep tail oil was clearer,tphospholipid content was lower and the degumming effect was better.(2)The factors and conditions affecting the deacidification effect of extracted sheep tail oil were determined by single factor test and response surface optimization test.The results showed that the optimum deacidification conditions were as follows: the best super alkali 0.5%,the best alkali temperature 48,the best alkali refining temperature 86,the best alkali refining time 40 min and the deacidification rate 90.94%.The acid value of the tail oil decreased significantly after deacidification,and the deacidification effect was better.(3)The factors and conditions affecting the decolorization effect of extracted sheep tail oil were determined by single factor test and response surface optimization test.The results showed that the optimum decolorization conditions were as follows: the addition amount of activated clay 3.5%,the decolorization temperature 83,the decolorization time 38 min,and the decolorization rate 77.19%.After decolorization the sheep's tail oil is lighter in color,and the decolorization effect was better.3.In order to make the refined sheep tail oil reach the plastic range and meet the crystal form requirements of the shortening,it was necessary to modify the oil.Comparing the three modification methods of hydrogenation,transesterification and fractionation,fractionation could not only improve the plasticity range and increase the content of beta'crystalline form,but also had the advantages of simple operation,low cost,no need to use catalyst,and no trans fatty acid would be produced.Therefore,the refined sheep tail oil was selected for fractionation.The extraction conditions were as follows: the equilibrium temperature 60,the equilibrium time 30 min,the crystallization temperature 30,the cooling rate 3/ h,the crystal growth time 12 h,the stirring rate 120 r / min,the centrifugation speed 10000 r / min,and the centrifugation time 25 min.4.The types and contents of fatty acids in raw sheep tail oil,fractional lipid-fixing oil and fractional liquid oil were determined by gas chromatography.Nine kinds of fatty acids were detected in three kinds of oils.After dry extraction,the saturated fatty acid content of segregated sheep tail oil increased from 55.38% to 57.41%,and the saturated fatty acid content of segregated sheep tail oil decreased from 55.38% to 53.90%.In addition,the content of monounsaturated fatty acids reduced from 42.36% to 39.63%,and the content of monounsaturated fatty acids increased from 42.36% to 43.29%.5.The homogeneous polycrystalline phenomena of raw sheep tail oil and fractionated lipid were determined by X-ray diffraction.The main crystal forms of the raw sheep tail oil and the dry-finished solid fat were both ?' crystal form.The ?' crystal form of the raw sheep tail oil was 53.69%,and the ?' crystal form of the dry-finished solid fat was 71.27%.The ?' crystal form of the refined fat obviously increased,and the tail oil had the advantage of preparing the base oil of the shortening.6.The type and proportion of emulsifier addition were determined by single factor test and mixture regression design test.The results showed that when the ratio of monoglyceride,lecithin and span 60 was 0.800:0.100:0.100,the water absorption and the caseinity simultaneously reached the maximum.7.Based on the sensory evaluation,the specific volume measurement,and the texture analysis,the bread of the commercially available shortening was compared with the bread before and after the modified sheep tail oil based shortening,and the results showed that the color,odor and taste of the bread baked with modified sheep tail shortening were higher than those baked with modified sheep tail shortening and the bread baked with marketable general shortening.The modified sheep tail oil shortening had a specific volume of 4.2 mg/g,which was higher than that of the commercially bread 3.8 mg/g and bread baked without modified sheep tail shortening 3.7 mg/g.The elasticity of bread baked with modified sheep tail shortening was 0.89,which was higher than the 0.81 of the commercially available general shortening and 0.70 of the before modified sheep tail shortening,and the chewability was 222.67 g,which was higher than the 220.14 g of commercially available general shortening and 204.21 g of before modified sheep tail oil shortening.