Optimization of lipid extraction process from heads of Litopenaeus vannamei using response surface methodology

Objective This study aimed to establish an optimized lipid extraction process from shrimp heads (a by-product of Litopenaeus vannamei) and evaluate the nutritional quality of the extracted lipids, thereby facilitating the high-value utilization of this aquatic by-product.

Methods Freeze-dried shrimp head powder was used as the raw material. A response surface methodology (RSM) was employed to optimize the lipid extraction process, with liquid-to-solid ratio (A), ultrasonic time (B), and ultrasonic temperature (C) as independent variables and lipid yield (Y) as the response value. A regression model was constructed to analyze the effects of the variables on lipid yield. Additionally, the phospholipid content and fatty acid composition of lipids extracted under optimal conditions were determined.

Results The quadratic regression model for lipid yield was established as follows:Y=12.432+0.363 75A+0.047 5B+0.078 75C+0.237 5AB−0.19AC+0.062 5BC−0.168 5A²−0.426B²−0.583 5C². The model was highly significant (P=0.004 9), while the lack-of-fit term was non-significant (P=0.119 1), indicating excellent goodness-of-fit. The predicted optimal extraction conditions were: liquid-to-solid ratio of 4.84 mL/g, ultrasonic time of 92.8 min, and temperature of 43.8 °C, with a theoretical lipid yield of 12.53%. Considering practical operational feasibility, the conditions were adjusted to a liquid-to-solid ratio of 5 mL/g, ultrasonic time of 90 min, and ultrasonic temperature of 40 °C. Under these modified conditions, the actual lipid yield was (12.37±0.38)%, which was in good agreement with the predicted value. Nutritional quality analysis revealed that the extracted lipids contained (251.98±1.73) mg/g of phospholipids. A total of 24 fatty acids were identified, among which polyunsaturated fatty acids (PUFAs) dominated, accounting for 39.01% of the total fatty acids. Notably, the combined content of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) reached 16.7%.

Conclusion The RSM-optimized lipid extraction process is stable and reliable, yielding lipids with high recovery rates that are rich in phospholipids and n-3 PUFAs. These findings highlight the potential of shrimp head lipids as a valuable functional ingredient, providing a theoretical basis for the sustainable processing and high-value utilization of crustacean by-products.