微波干燥预处理对苹果渣提取果胶的影响

    Effect of microwave drying pretreatment on extraction of pectin from apple pomace

    • 摘要: 利用微波干燥技术对湿苹果渣进行预处理,研究了微波干燥预处理对苹果渣提取果胶的影响。以探索一种新的干燥方法和提高果胶品质。结果表明:微波能量越大,苹果渣组织结构破碎越严重,其复水能力越弱;但对苹果渣颜色无显著影响;微波干燥预处理能显著提高果胶得率,微波预处理条件为300 W、15 min、7.5×10-2 kW?h或500 W、10 min、8.3×10-2 kW?h时微波预处理苹果皮渣的果胶提取得率比对照提高了50%左右,是较为适宜的微波处理条件,但微波能量大于8.3×10-2 kW?h时,对果胶得率有不利影响;微波干燥预处理对果胶半乳糖醛酸含量无显著性影响,但显著提高了果胶的酯化度、固有黏度和黏均分子质量。

       

      Abstract: In order to develop a new method for drying apple pomace and improve the quality of pectin which was extracted from dried apple pomace, effect of microwave drying pretreatment(MDP) on extraction of apple pectin from apple pomace was investigated. With increasing the microwave energy of MDP, more rupture in the tissue of apple pomace was observed using scanning electron microscope, and the rehydration capacity of apple pomace decreased. However, the color of apple pomace didn’t change significantly. The pectin yield extracted from apple pomace was significantly increased after MDP (p<0.05), an about 50% increase of pectin yield was obtained at 300W for 15 min (7.5×10-2 kW?h) or at 500 W for 10 min (8.3×10-2 kW?h), but the microwave energy for MDP greater than 8.3×10-2 kW?h led to the degradation of pectin in apple pomace. The degree of esterification (DE, %), intrinsic viscosity (ηi) and the viscosity-average molecular weight (Mw,ave) of apple pectin obtained from apple pomace using MDP were significantly increased, while its galacturonic acid (GA, %) was not changed significantly.

       

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