Comparison of improvement in learning and memory ability of walnut oil extracted by aqueous enzymatic extraction and cold pressing extraction

Abstract Rich in unsaturated fatty acids, walnut oil provides a number of physiological benefits, including a reduction in the risk of cardiovascular disease and a delay in the aging process. In this work, walnut oil was prepared using the aqueous enzyme process and cold pressing method, and it was then analyzed using HPLC and FTIR. The characterization results show that the walnut oil extracted by the aqueous enzyme method outperformed the pressing oil in content of LLL by 11.64%, LLLn by 9.16% and OLL by 4.08%. But this oil had significantly less OLnLn (‐) than the pressing oil (7.90%). The Morris water maze and shuttle box tests of ICR mice revealed a notable improvement in the memory of the animals administered walnut oil. Among them, mice fed the walnut oil extracted by aqueous enzyme method showed a much shorter escape latency and a significantly higher rate of active avoidance reaction ( p < 0.05, p < 0.01) than mice fed cold pressing method. With the prolongation of time, the mice even performed better than the positive control PIR group in all aspects. In summary, the quality of walnut oil extracted by aqueous enzyme method is better than that by cold pressing method. Practical Applications : Walnut oil prepared by aqueous enzymatic extraction can improve learning ability, is healthy and pollution‐free, and can be utilized as a dietary supplement in ordinary life.