水酶法提取紫海胆性腺脂质的工艺优化及提取方法对其品质的影响

Process optimization of lipid extraction from the gonad of Heliocidaris crassispina via enzyme-assisted aqueous method and effect of extraction methods on its quality

以福建紫海胆(Heliocidaris crassispina)性腺为研究对象,采用单因素实验和正交实验优化水酶法提取紫海胆性腺脂质工艺,并基于气相色谱-质谱联用(GC-MS)、二醇基硅胶固相萃取(Generik Diol SPE)、高效薄层色谱(HPTLC)和差示扫描量热(DSC)等技术,以脂质得率、理化性质、脂肪酸组成、营养指标、脂质组成、熔融与结晶特性为指标,探讨了水酶法、Folch法和Matyash法对紫海胆性腺脂质品质的影响。结果表明:水酶法提取紫海胆性腺脂质最佳工艺条件为料液比1∶20、中性蛋白酶添加量7500 U/g、酶解时间5 h、酶解温度50℃和pH 7,该条件下脂质得率为23.22%,显著低于Folch法(27.27%)和Matyash法(27.14%);与Folch法和Matyash法相比,水酶法提取的紫海胆性腺脂质过氧化值(0.006 g/100 g)较低,碘值(95.77 g/100 g)较高,饱和脂肪酸含量(51.48%)较低,多不饱和脂肪酸含量(34.53%)较高,EPA与DHA总含量(15.04%)较高,营养指标较好,磷脂含量(4.23%)较低,熔融与结晶温度较低。综上,虽然水酶法提取紫海胆性腺脂质工艺存在得率低、破乳工艺复杂、磷脂选择性差等技术瓶颈,但其反应条件温和、绿色安全,所提取的脂质品质佳,具有较好的营养价值、较低的熔融与结晶温度,适合高品质海洋膳食脂质的研制。

The lipids from the gonad of Heliocidaris crassispina(Fujian Province, China) was extracted using enzyme-assisted aqueous extraction method(EAE), and the extraction process was optimized by single factor experiment and orthogonal experiment. By applying gas chromatography-mass spectrometry(GC-MS), Generik Diol solid-phase extraction(SPE), high-performance thin layer chromatography(HPTLC) and differential scanning calorimetry(DSC) technologies, the quality of EAE lipid was comparatively characterized with that of Folch method and Matyash method with the lipid yields, physicochemical properties, fatty acid compositions, nutritional indexes, lipid compositions, melting and crystallization characteristics as indicators. The results showed that the optimal conditions of EAE process were determined as follows: solid-liquid ratio 1∶20, neutral protease dosage 7 500 U/g, enzymatic hydrolysis temperature 50℃,enzymatic hydrolysis time 5 h, and pH 7. The lipid yield was 23.22% under above conditions, which was significantly lower than that of Folch method(27.27%) and Matyash method(27.14%). Compared with Folch method and Matyash method, the lipids from the gonad of Heliocidaris crassispina extracted by EAE had lower peroxide value(0.006 g/100 g), higher iodine value(95.77 gI/100 g), lower content of saturated fatty acids(51.48%), higher content of polyunsaturated fatty acids(34.53%), higher total content of EPA and DHA(15.04%), better nutritional indexes, lower phospholipids content(4.23%) and lower melting temperature and crystallization temperature. In conclusion, though bearing the shortages of low yield, complicated demulsification process and poor selectivity of phospholipids, EAE surpassed Folch method and Matyash method for milder conditions, eco-friendly initiatives, better quality, better nutritional value, lower melting and crystallization temperature of lipids, and suitable for the development of high quality marine dietary lipids.