Box-Behnken法优化提取荔枝渣中果胶工艺

以荔枝渣为材料,采用超声波辅助酸法提取工艺,运用Box-Behnken试验设计方案获得超声波预处理时间、功率和料液比等因素对果胶得率的影响规律,并结合质构仪分析果胶硬度、黏度、酯化度等指标。结果表明:超声波预处理荔枝渣提取果胶最佳工艺为超声时间14.8 min、超声功率300 W、料液比1∶10.7,在此基础上选择pH 2的盐酸溶液提取,乙醇沉淀时液-液体积比1∶1.5,沉淀时间90 min,果胶理论得率17.86%,实测得率为17.38%。所得果胶黏度为55.8×10-3 Pa·s,酯化度为40.7%,质构特性分析表明所得荔枝渣果胶硬度平均值为40.400 g,弹性平均值为55.51%,黏性绝对平均值为12.880 g,果胶样品色泽较好,胶凝度高。

Optimization of Extraction Process for Pectin from Litchi Residues by Box-Behnken Design

The ultrasonic-assisted acid extraction of pectin from litchi residues was optimized using Box-Behnken design. The
yield of pectin was investigated as a function of ultrasonication time, ultrasonic power and solid-to-solvent ratio. Litchi pectin
was tested by a texture analyzer for hardness, viscosity and degree of esterification. The optimum conditions for extracting pectin
from litchi residues were found to be ultrasonic-assisted extraction for 14.8 min at a power of 300 W using pH 2 hydrochloric acid
solution with a solid-to-solvent ratio of 1:10.7, addition of ethanol as a precipitant with a ratio to extract of 1:1.5 by volume, and
90 min precipitation. The maximum predicted yield of pectin under the optimized conditions was 17.86%, which was close to
the experimentally observed value of 17.38%. The pectin showed a viscosity of 55.8×10-3 Pa·s and a degree of esterification of
40.7%, and texture analysis indicated that the average hardness, elasticity and cohesiveness were 40.400 g, 55.51% and 12.880 g,
respectively. In addition, good color and gel-forming properties were observed.