不同提取工艺对椰子油品质与货架期的影响Analysis of quality and shelf life changes of coconut oil under different extraction processes
摘要
旨在为椰子油的加工和贮藏提供参考，以椰浆为原料，采用热榨、低温压榨、索氏抽提、冻融（-20、-40 ℃及-80 ℃）、发酵（24 h和48 h）和复合酶解9种工艺提取椰子油，对比分析椰子油的提取率、脂肪酸组成、基本理化指标、脂质伴随物含量及体外抗氧化活性的差异，并建立了Arrhenius货架期预测模型。结果表明：复合酶解工艺提取的椰子油品质相对最佳，其椰子油中月桂酸（C12∶ 0）含量（49.03%）最高，多酚（0.48 mg/kg)和VE(3.51 μg/mL)含量最高，抗氧化活性也明显优于其他工艺提取的椰子油；不同贮藏温度（40、60 ℃和80 ℃）下，9种工艺提取的椰子油的酸值和过氧化值均随着贮藏时间延长而逐渐增加，且温度越高增长越快，整体符合一级动力学模型；基于过氧化值变化建立的货架期预测模型要优于基于酸值变化建立的；基于过氧化值模型计算的不同工艺提取的椰子油在25 ℃和35 ℃下的货架期不同，其中，48 h发酵法和低温压榨法提取的椰子油分别在25 ℃和35 ℃下的货架期最长。综上，不同工艺提取的椰子油呈现出明显的功能特性与稳定性差异，其中复合酶解法更适于制备高活性、高功能性的特色油脂，48 h发酵法适用于开发追求常温长货架期的常规产品，而低温压榨法则更适合对较高温度（35 ℃）贮藏稳定性有要求的应用场景。 To provide a reference for the processing and storage of coconut oil, with coconut milk as raw material, coconut oil was prepared by nine extraction processes, namely hot pressing, cold pressing, Soxhlet extraction, freeze-thawing at -20, -40 ℃ and -80 ℃, fermentation for 24 h and 48 h, and complex enzymatic hydrolysis. The differences in extraction yield, fatty acid composition, basic physicochemical indexes, lipid concomitants content and in vitro antioxidant activity of coconut oil were compared and analyzed, and an Arrhenius model for shelf life prediction was established. The results showed that the quality of coconut oil extracted by complex enzymatic hydrolysis was relatively optimal, with the highest content of lauric acid (C12∶ 0) at 49.03%, its polyphenols (0.48 mg/kg) and vitamin E（351 μg/mL） contents were the highest, and its antioxidant activity was also significantly superior to that obtained by other processes. At different storage temperatures (40, 60 ℃ and 80 ℃), the acid value and peroxide value of coconut oil extracted by the nine processes gradually increased with prolonged storage time, and the higher the temperature, the faster the increase, generally conforming to the first-order kinetic model. Moreover, the shelf life prediction model established based on the change of peroxide value was superior to that based on acid value. The predicted shelf life values of coconut oil extracted by d