摘要:
采用超声波辅助法从菠萝皮中提取果胶,分别对草酸铵浓度、固液比、沉析pH值和提取温度等4个影响果胶提取率的因素进行考察。依据单因素试验结果进行正交试验,通过R和K值的比较,确定沉析pH值对果胶提取率的影响较大,并确定最佳试验条件:沉析pH值3.5,提取温度75℃,草酸铵浓度7g·L-1,固液比1∶30,果胶提取率可达到7.32%。红外分析结果显示,果胶在1 051cm-1处的吸收峰证明有乙酰基的存在,1620cm-1、1 749cm-1处吸收峰的强弱对比表明菠萝皮提取果胶为低酯果胶。
Abstract:
In this paper,pectin was extracted from pineapple peel using Ammonium oxalate method assisted by ultrasonic, four factors such as Ammonium oxalate concentration,precipitation agent pH value,extracting solid-liquid ratio and extraction temperature which effect on pectin extraction yield was investigated separately.Orthogonal test was utilized on the basis of results of single-factor test.Through comparing R and K value,it could be concluded that precipitation agent pH value had great influence on pectin extraction yield.The best experiment scheme was reached that precipitation agent pH value was 3.5,Ammonium oxalate concentration 7g·L-1,extraction temperature 75℃ and extracting solid-liquid ratio 1∶30.The pectin exacting yield could reach 7.32%.FT-IR spectroscopy of pineapple rind pectin suggested that absorption peak on 1 051cm-1 was caused by acetyl groups and peaks density contrast on 620cm-1 and 1 749cm-1 indicated that pineapple peel pectin was a low ester pectin.
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