储藏温度对棕榈油基塑性脂肪结晶和宏观性能的影响

Effect of storage temperature on the crystallization and macroscopic properties of palm oil-based plastic fats

旨在为塑性脂肪储藏和实际应用提供参考,使用人造奶油中试设备制备了以棕榈硬脂(PS)与棕榈液油(OL)为油基的起酥油PO和以PS、OL与稻米油(RBO)为油基的起酥油PRBO,对其油基的脂肪酸组成、甘油三酯组成、固体脂肪含量(SFC)、结晶速率和结晶熔化曲线进行了表征,分析了其刚完成熟化时和在4、15、20、25、30℃下储藏4个月后的熔化曲线、XRD晶型、微观结晶形态、硬度和打发性能。结果显示:与PO油基相比,PRBO油基的多不饱和脂肪酸、三饱和脂肪酸甘油三酯和三不饱和脂肪酸甘油三酯含量较高;PRBO油基的SFC在低温时小,高温时大;PRBO油基在10℃和20℃结晶速率更快;PRBO油基低温时的熔化峰低,高温时的熔化峰高,结晶温度也是如此;与刚完成熟化时相比,PRBO和PO的SFC在4~25℃储藏过程中上升,其中4℃下上升最明显;30℃储藏条件下,PRBO和PO的熔化峰均向高温位置发生明显位移;刚完成熟化时PO和PRBO均为细腻的β′结晶,30℃储藏4个月后均基本转变为粗大的β结晶,后硬明显,打发性能下降,其余储藏温度下样品在10℃没有出现后硬,在15~25℃有不同程度后硬,但并不影响打发性能;25℃储藏条件下样品的β′晶型最稳定,后硬程度最小;与PO相比,PRBO在低温时软,高温时硬,有利于产品应用。综上,建议PO和PRBO于25℃室温储藏,避免大于30℃的高温储藏。

To provide reference for the storage and practical application of plastic fats,PO shortening based on palm stearin(PS)and palm olein(OL),and PRBO shortening based on PS,OL and rice bran oil(RBO)were prepared by margarine pilot equipment.The fatty acid composition,triglyceride composition,solid fat content(SFC),crystallization rate and DSC crystallization melting curve of oil base were characterized.The melting curve,XRD crystal form,microcrystalline morphology,hardness and whipping performance of PRBO and PO just after tempering and those stored at 4,15,20,25℃and 30℃for 4 months were studied.The results showed that compared with PO oil base,the contents of polyunsaturated fatty acids,trisaturated fatty acid triglyceride and triunsaturated fatty acid triglyceride of PRBO oil base were higher;SFC in PRBO oil base was small at low temperature and large at high temperature.The crystallization rate of PRBO oil base was faster at 10℃and 20℃.The melting peak of PRBO oil base was low at low temperature and high at high temperature,as was the crystallization temperature.The SFC in PRBO and PO increased at 4-25℃,and the increase was most obvious at 4℃compared with just after tempering.At 30℃,the melting peaks of PRBO and PO shifted to high temperature.PO and PRBO were fineβ′crystals at just after tempering.After 4 months of storage at 30℃,they were basically transformed into coarseβcrystals with obvious post hardening and reduced whipping performance.At other storage temperatures,the sample did not exhibit post hardening at 10℃,and had different degrees of post hardening at 15-25℃,but it did not affect the whipping performance.Theβ′crystals of the samples stored at 25℃was the most stable and the degree of post hardening was the least.Compared with PO,PRBO was soft at low temperature and hard at high temperature,which was conducive to product application.In summary,it is recommended to store PO and PRBO at 25℃room temperature,and avoid high temperature greater than 30℃storage.