| As the traditional shortening,lard have the crisp well and is the production of pastry papaya important fat.Lard contains ingredients that are beneficial to the human body,such as more fatty acids of body needing,more abundant fat-soluble vitamins.The trans fatty acids in the lard are lower than the vegetable butter.when Lard is heating,the oil kept volatile,diffuse out the unique flavor.the snack that is made by lard eat up with a mouth-watering flavor.The distribution of fatty acids in the sn-2 position of lard is mainly palmitic acid(90% ~ 100%).This special triglyceride structure similar to human milk fat makes it easier to digest and absorb.In this paper,the lard of removing 68.3% cholesterol was used instead of traditional vegetable butter to make cookies.On this basis,the production process of lard cookies was optimized by fuzzy comprehensive evaluation and response surface.The gas chromatography-mass spectrometry compares the fatty acid and the relative content of lard cookies and vegetable butter cookies.The shelf life of Arrhenius shelf that is used to predict shelf life of the product was established.The development and production of biscuits provides a theoretical basis.The main research results are as follows:1.The single factor experiment was used to select the amount of citrus cellulose,the reaction time and the reaction temperature as the factor and the removal rate of cholesterol as the response value.According to the orthogonal experiment design principle,four factors and three levels of orthogonal optimization analysis is used.The influence of each factor on the response value is discussed according to the analysis of the difference.The results showed that the optimum conditions for the removal of cholesterol in lard were as follows: the addition amount of citrus peel was 5%,the reaction time was 50 min and the reaction temperature was 60 ℃.Under these conditions,the removal rate of cholesterol in lard was 61.03 %.2.The changes of acid value,peroxidation value and conventional physical and chemical indexes of edible lard and lard of removing cholesterol,were studied and compared.The fatty acid types and relative contents of edible lard and lard of removing cholesterol were studied.The acid value of the lard decreased from the initial 1.63 mg/g to 1.01 mg/g,and the acid value of the lard after the treatment was in line with the national standard.The peroxidation value of the lard was reduced from 0.037g/100 g to 0.032g/100 g,and the peroxidation value after deprivation was reduced by 0.005g/100 g.The content of cholesterol in lard decreased from 98.5 mg/100 g to 38.6 mg/100 g,and its content decreased by 59.9 mg/100 g and the type of fatty acid did not change.3.Using the fuzzy comprehensive evaluation and the response surface optimization analysis,the optimum technological parameters of the lard cookies were obtained: the amount of the white sugar was 30%,the lard was 59%,the baking time was 20 min,the baking temperature was 171 ℃And the regression equation was: Y1=82.80-2.25A+1.47B-0.87C+1.08D-2.50AB-0.51AC-1.25AD-1.85BC-0.25BD-1.75CD-10.01A2-6.93B2-4.19C2-2.01D2.R2=0.9829,the lack of fit items of equation is not significant,the equation significantly effective,under the conditions,the product quality are the best.4.According to the trans linoleic acid and the transoleic acid standard and the decoction of the cholesterol lard cookies and the plant butter butter cookies of the fatty acid methyl ester GC-MS total ion flow diagram and combined with the area normalization method,the trans fatty acid content of removing cholesterol lard biscuits is 2.27g/100 g,which is lower than the maximum content of trans fatty acids of 3g/ 100 g,and the trans fatty acid content of plant butter cookies is 3.98g/100 g,which is higher than the trans The highest level of fatty acids is 3g/100g;therefore,the health and safety of removing cholesterol lard biscuits is higher than that of vegetable butter cookies.5.Under the condition of storage at 25 ℃,the acid value of lard cookies increased with the increase of storage time,from 1.471 mg/g to 3.517 mg/g for 90 days.Although the acid value was increasing during storage,the maximum acid value was 3.517 mg/g lower than that of GB7100-2015 the maximum acid value 5 mg/g.The peroxidation value of lard cookies increased with the increase of storage time from the initial 0.041g/100 g to 0.311g/100 g of storage for 84 days.When the storage period reached 77 days,the lard cookies had a peroxide value of 0.271g/100 g,and the peroxide value was greater than the maximum peroxidation value specified in GB7100-2015 0.25g/100 g.The total number of bacterial changes in lard cookies is small and always varies between 200 and 300 cfu/g,the total number of bacteria is much lower than the total number of GB4789.2 104cfu/g.6.The change of the peroxide value with the time of the lard cookies in the accelerated temperature storage condition is in accordance with the first order kinetic model.The results show that when the number of detection times is 3,the prediction error is-2.74%,when the number of points detected is 9,the detection error is-5.48%,when the detection interval is 5 d at 35 ℃,the detection interval is 3d at 45 ℃,the detection interval is 2d at 55 ℃,the detection error is-2.74%.On this basis,the shelf life prediction model of lard cookies was established as lnk=-2952.5×1/T+6.6613,the correlation coefficient of the model was R2 = 0.9599,and the forecast period of lard cake at 25 ℃ was 71 d,The error is-2.74%,the prediction effect is better. |
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