热处理时间对牡丹籽油理化性质及抗氧化活性的影响

Effects of heat treatment time on physicochemical properties and antioxidant activity of peony seed oil

【目的】研究比较微波和烘烤预处理对牡丹籽油理化性质及抗氧化活性的影响,以期为牡丹籽油的制备及品质控制提供科学指导。【方法】采用微波(700 W,0.5、1、1.5、2 min)和烘烤(120℃,10、20、30、40 min)对油用牡丹籽进行预处理后分离牡丹籽油,以未经任何预处理为对照,分析2种方式的处理时间对牡丹籽油理化性质(提油率、水分及挥发物、酸值、碘值等)和抗氧化活性的影响。【结果】经微波和烘烤处理后的牡丹籽油总提取率均有所增加,在微波2 min和烘烤30 min时增加幅度最大,分别提高9.44%和12.08%。在微波处理下,随着处理时间的延长,牡丹籽油的酸值、水分及挥发物含量、多酚含量及抗氧化活性均呈下降趋势,多酚和水分及挥发物含量在微波处理2 min时最低,分别为2.52μg/mL和11.59%;但碘值、2-硫代巴比妥酸(TBA)值和p-茴香胺值表现出明显增加趋势,TBA值和p-茴香胺值在微波处理2 min时达最大值,分别为261.39和2.14,皂化值呈先上升后趋于平缓的变化趋势。在烘烤处理下,随着处理时间的延长,牡丹籽油的酸值和水分及挥发物含量明显增加,而碘值、皂化值、TBA值和p-茴香胺值呈降低趋势,酸值在烘烤40 min时达最高值(162.28 mg/g),在10 min时碘值和皂化值达峰值,分别为147.96 g/100 g和173.35 mg/g;多酚含量和抗氧化活性呈先上升后下降的变化趋势,在烘烤20 min时最高,多酚含量为5.25μg/mL。【结论】微波和烘烤预处理均对牡丹籽油的理化性质及抗氧化活性产生明显影响,且2种处理方式的影响效果具有明显差异性。综合考虑,油用牡丹籽微波预处理在700 W下以1.5~2 min适宜,烘烤预处理在120℃下以20~30 min适宜。

【Objective】By comparing the effects of microwave and roasting pretreatments on the physicochemical properties and antioxidant activity of peony seed oil(PSO),the aim was to provide scientific guidance for the production and quality control of PSO.【Method】The oil of peony seeds was isolated after pretreatment by microwave(700 W for 0.5,1,1.5,2 min)and roasting(120℃for 10,20,30,40 min),without any pretreatment was as control,and the effects of the treatment times of the two methods on physicochemical properties(oil extraction rate,moisture and volatile matter,acid value and iodine value)and antioxidant activity were analyzed.【Result】The total extraction rate of the peony seed oil increased after microwave and roasting treatment.The extraction rate of PSO increased by 9.44%and 12.08%after microwave for 2 min and roasting for 30 min,respectively.Under microwave treatment,with the increase of treatment time,the acid value,moisture and volatile matter contents,polyphenol content and antioxidant activity of PSO decreased,the lowest contents of polyphenol,moisture and volatiles were detected at microwave treatment for 2 min(2.52μg/mL and 11.59%,respectively),while the iodine value,saponification(TBA)value,and p-aniside value increased greatly,the value of TBA and p-anisidine reached the maximum value of 261.39 and 2.14,respectively under microwave treatment for 2 min.The saponification value showed a trend of rising first and then flatten.Under roasting treatment,the acid value,moisture and volatile matter contents of PSO increased greatly with the increase of treatment time,however,iodine,saponification,TBA,and p-anisidine values decreased.The acid value reached the highest value of 162.28 mg/g at 40 min of roasting,and the iodine value and saponification value reached the peak of 147.96 g/100 g and 173.35 mg/g at 10 min respectively.The polyphenol content and antioxidant activity showed a first increasing and then decreasing trend,the highest polyphenol content(5.25μg/mL)was observed at roasting for 20 min.【Conclusion】The physicochemical properties and antioxidant activities of PSO were greatly affected by microwave and roasting,and the effects of the two heat treatment methods have obvious differences.In general,the microwave pretreatment on oil peony seeds at 700 W is suitable for 1.5 to 2 min,and the roasting pretreatment at 120℃is the best for 20 to 30 min.