Advanced Research On Isolation And Antioxidative Activity Of Malus Pumila Polysaccharides From Apple Pomace

Currently plant originated polysaccharide with biological activities is one of a great focus in life science. There are abundant and diverstile Malus Pumila polysaccharides in apple pomace, however, few systematic isolation and analysis have been done about them. Apple pomace produced from juice squeezing by Meixian plant, Shaanxi Hengxing Fruit Juice Company LTD. was employed to prepare polysaccharides with either one-step-extracting or step-on-extracting technology in this study. Yields and anti-oxidative activity were compared between each process and each product. Through systematic isolation and measurement Malus pumila polysaccharide(s) which is of high biological activity was screened and its preparing technology was optimized. All results are as flowing:(1) It is impossible with one-step-extracting methods likes water, alkali, acid, to extract the Malus Pumila polysaccharides thoroughly, and polysaccharides with different solubility were obtained with different methods. Total yield of polysaccharide from water-alkali-acid step-on-extracting method got to 417.1±12.1g/kg DWB,far more than that from the traditional acid-extracting process of pectin production, 97.9±5.8g/kg DWB.(2) Through the measurement and thorough comparison of the scavenging capacity to O2-·,·OH,DPPH·and the reducing capacity of each half pure Malus pumila polysaccharide, The index of reducing capacity was screened the best one to indicate the anti-oxidative activity of Malus pumila polysaccharide.(3) In terms of reducing ability, no matter one-step-extracting or step-on-extracting method., the half pure product of Malus pumila polysaccharides which were extracted by other methods, all showed higher anti-oxidative activity than pectin polysaccharide(APS-AcEI), among which the highest activity occurs with the water-acid-alkali step-on-extracting method(APS-AlTⅡ) and the two stage extraction method(water-acid)(APS-AcI')。It concludes that the best extraction technique for Malus pumila polysaccharide is the water-acid-alkali step-on-extracting method at high temperature.(4) Different anti-oxidative activity exists in the pure composition within the half pure product of Malus pumila polysaccharide produced with different extraction methods. Each composition showed different anti-oxidative activity, most of the pure composition displays a trend that active of the water eluting composition (weak polarity) is stronger than that of the salt eluting compositions, and the less the molecular weight, the more stronger the anti-oxidative activity, thus almost the same activity obtained with the similar molecular weight product. Except for APS-AlTⅡextracted in the three stage extraction method(water→alkali→Acid), within which the activity of the salt eluting compositions(APS-AlTⅡ3,APS-AlTⅡ4)were more stronger than that of the water composition.The anti-oxidative activity is different between the half pure product and its pure compositions. Generally, half pure product possessed a more stronger anti-oxidative activity, except the alkali-extracted polysaccharide(APS-AlTⅡ), which activity of pure composition(APS-AlTⅡ4) was slightly stronger than that of half pure product.