红外预处理对低温压榨碧根果油品质及贮藏稳定性的影响

Effect of Infrared Pretreatment on Quality and Storage Stability of Cold-Pressed Pecan Oil

以碧根果仁为材料,利用红外(infrared,IR)预处理22、41、68、104、148 s使其中心温度分别达到70、90、110、130、150℃,通过出油率、脂肪酸组成、脂质伴随物含量和理化指标测定、微观结构观察以及抗氧化能力和贮藏稳定性分析,研究IR预处理对低温压榨碧根果油品质以及贮藏稳定性的影响。结果表明:IR预处理能显著提高碧根果仁的出油率,与对照组相比提高了11.10%~58.42%;但对低温压榨碧根果油的脂肪酸组成无明显影响;经IR预处理后碧根果油脂肪酶和多酚氧化酶活力显著降低(P<0.05);非酶促褐变指数、类胡萝卜素的释放以及总酚含量与IR预处理时间呈正相关,低温压榨碧根果油的颜色随着果仁预处理时间的延长而加深;IR预处理148 s低温压榨碧根果油的γ-生育酚含量略有降低但并不显著,1,1-二苯基-2-三硝基苯肼自由基清除能力和铁离子还原能力较对照组分别提高了23.52%和13.16%,贮藏稳定性显著增强。综上,IR预处理148 s是获得低温压榨碧根果油的最优预处理方式。该研究结果可为IR在低温压榨碧根果油制备中应用提供一定的理论依据。

After infrared(IR)pretreatment for 22,41,68,104 and 148 s,the internal temperature of pecan kernels reached 70,90,110,130 and 150℃,respectively.To investigate the effect of IR pretreatment on the quality and storage stability of cold-pressed pecan oil,oil yield,fatty acid composition,lipid concomitants,physicochemical indicators,microstructure,and antioxidant capacity and storage stability were analyzed.The results showed that IR pretreatment increased the oil yield of pecan kernels by 11.10%–58.42%compared with the control group,but had no significant effect on the fatty acid composition of cold-pressed pecan oil.Moreover,IR pretreatment significantly the activities of lipase and polyphenol oxidase in pecan oil(P<0.05).Non-enzymatic browning index,the release of carotenoids and the content of total phenolics were positively correlated with IR pretreatment time,and the color of cold-pressed pecan oil turned darker with increasing time of IR pretreatment.Compared with the control group,IR pretreatment for 148 s resulted in a slight but not significant reduction inγ-tocopherol content(P>0.05),and a 23.52%and 13.16%increase in 1,1-diphenyl-2-picrylhydrazyl(DPPH)radical scavenging capacity and ferric reducing antioxidant power(FRAP),respectively,thereby significantly enhancing the storage stability.To summarize,IR pretreatment for 148 s is the best pretreatment method to obtain cold-pressed pecan oil.The results of this study provide a theoretical basis for the application of IR pretreatment in the preparation of cold-pressed pecan oil.