Preparation And Application Of Melt-Resistant Ice Cream Oil Based On Palm Oil

Oil is one of the main components of ice cream,which plays an important role in the properties and texture of ice cream.The traditional ice cream oil is mainly coconut oil and palm oil,but they have low melting points,which makes ice cream prone to melting and a series of property changes during the process of the production,storage and transportation.In this paper,palm oil intermediate fraction(PMF),coconut oil(CO)and butter were used as the main raw materials to prepare anti-melting ice cream special oil by physical compounding and enzymatic transesterification,and then the anti-melting ice cream samples were prepared by using the special oil.The main research contents and results are as follows :1.The anti-melting ice cream special oil was prepared by physical mixing method,and the physical and chemical indexes,SFC value,melting crystallization curve and compatibility of the oil were compared and analyzed.The results showed that the ΔSFC value of the physical composite group with the mixing mass ratio of3:6:1 at 28℃ PMF : 40℃ PMF : butter of was closer to zero,indicating that the mixed oil at this ratio did not have obvious partial crystal and eutectic phenomenon and had better compatibility.At the same time,the iodine value of the oil under the composite ratio was 40.63 g/100 g,and the acid value was 1.06 mg KOH/g,indicating that the saturation degree was high and the free fatty acid content in the oil was low,so the oxidation stability was good.It has a melting point of 33.35℃ and a lower SFC value at 35℃,so it has better stability and mouth melting,and can be used as a physical compound oil(PF).2.The palm-based anti-melting ice cream special oil was prepared by enzymatic transesterification.The oil ratio and enzymatic reaction conditions were optimized by single factor experiment with the sliding melting point and SFC value of oil as response indexes.The results showed that the optimum ratio of CO : 40℃PMF was 5:5,the optimum reaction conditions were 10% Lipozyme TL IM,the reaction time was 4h,and the reaction temperature was 60℃.The enzymatic transesterification oil(IF)under this condition had a higher SFC value at 15℃ ～30℃ compared with the oil without transesterification(Non-IF),indicating that the enzymatic transesterification increased the medium melting point component content of the oil,and reduced the high melting point component content of the oil.The SFC value was lower at 35℃ while the melting point was higher,which improved the melting point of the oil while ensuring the mouth melting.It can be used as an enzymatic transesterification oil(IF).3.The composition of fatty acids and triglycerides,thermodynamic properties such as sliding melting point,solid fat content and melting curve,crystal form and isothermal crystallization kinetics of PF,Non-IF and IF were determined and analyzed.The results showed that the highest content of diacylglycerol(DAG)in IF was 21.81%,and it contained more types of triglycerides(TAG).Compared with Non-IF,the content of monounsaturated triglyceride(SUS)in IF increased by 6.48%,and the contents of trisaturated triglyceride(SSS)and triunsaturated triglyceride(UUU)decreased by 2.72% and 3.99%,respectively,indicating that the fatty acid on the glycerol skeleton of IF oil was rearranged during enzymatic transesterification,which led to higher SFC value of IF at 15℃ ～ 30℃and right shift of endothermic peak in melting curve.According to X-ray diffraction(XRD),it was found that the content of β′ crystal form in PF,Non-IF and IF was 93.2%,84.5% and 71.2%,respectively,indicating that all three were dominated by β′ crystal form,which was conducive to the formation of fine crystals to bring delicate taste.The minimum content of β’ crystal of IF indicates that the hardness of IF oil is better.According to the Avrami equation,it is found that the n value of IF tends to 1 at low temperature(5℃ ～ 20℃),indicating that it is instantaneous nucleation and rod-like growth and the crystal growth rate is the fastest.At 25℃,the n value tends to 3,indicating that it is instantaneous heterogeneous nucleation and sporadic growth.It is found that at the same temperature,the n value of IF is always smaller than that of Non-IF,and the K value is always larger than that of Non-IF,indicating that the nucleation rate and crystal growth rate of IF are faster than those of Non-IF.which is conducive to the formation of fine and uniform crystals.In summary,IF is an ideal ice cream oil.4.The enterprise ice cream formula oil and the above prepared Non-IF,IF and PF were used to make ice cream as control group 1,control group 2,anti-melting group 1 and anti-melting group 2.The properties of ice cream were analyzed by measuring the expansion rate,melting rate and sensory evaluation index of ice cream.The expansion rate and sensory evaluation score of the anti-melting group 1 were58.36% and 81.6,respectively,which were second only to 64.15% and 84.8 of the control group 1.The melting rate of anti-melting group 2 was the lowest,only49.78%,which was lower than 53.70% of anti-melting group 2,indicating that the anti-melting ability of anti-melting group 1 and anti-melting group 2 was significantly better than that of the two control groups.It was found that the properties of IF ice cream were better,second only to commercial ice cream,but the melting resistance was far better than commercial ice cream.