Research on Ultrasonic Extraction of Pectin in Pineapple Peel

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.