The Degradation Of Pectin Induced By Dynamic High Pressure Microfluidization (DHPM)

Pectin is a complex heteropolysaccharide which is widely distributed in the cellwalls and middle lamella of most plants. Pectin is commonly used as gelling agent,stabilizer, drug carrier and fat replacer in food, pharmaceutical and cosmeticsindustries. But the degradation is often exist during the manufacturing process. Thistopic studies the influence of pressure, times, ethanol solvent on DHPM treatedLow-methoxyl (LM) and High-methoxyl (HM) pectin, and the change of functionalproperties, structure and physicochemical properties of DHPM-treated LM andHM-pectin were evaluated by various indicators such as turbidity, texture properties,rheological properties, intrinsic viscosity, molecular weight, particle size, reducingsugar, Fourier transform infrared spectra, surface morphology. In this paper, theconclusion are as follows:(1).LM-pectin was degraded by DHPM. The extent of degradation increasedwith DHPM pressure and number, which was shown by the intrinsic viscosity,molecular weight and particle size of LM-pectin decreased, whereas the amount ofreducing sugars increased. At the same time, the surface topography of LM-pectinwas changed from foliated structure to filament structure. The mechanism ofDHPM-induced degradation of LM-pectin mainly comes from the rupture ofglycosidic bond, did not occur to demethoxylation and elimination reaction. Fouriertransform infrared spectra showed the intensity of absorption peak for1744.8cm-1(C=O) increased with increasing DHPM pressure.(2).HM-pectin was also degraded by DHPM. The extent of degradationincreased with DHPM pressure and number, which was shown by the turbidity, gelstrength, hardness, chewiness, stickiness, intrinsic viscosity, molecular weight andparticle size of HM-pectin decreased, whereas the amount of reducing sugars andgumminess increased. At the same time, the surface topography of HM-pectin waschanged from foliated structure to smaller chips. Fourier transform infrared spectrashowed DHPM had no effect on the primary structure of HM-pectin. The mechanismof DHPM-induced degradation of high-pectin mainly comes from the rupture of glycosidic bond, did not occur to demethoxylation and elimination reaction.(3).The effects of ethanol solvent on the degradation of HM-pectin induced byDHPM were investigated. Before DHPM-treated, it was found that the particle sizeincreased and molecular weight remain unchanged of HM-pectin, whereas theamount of reducing sugars decreased with the concentration of ethanol increasedfrom0%to10.0%. At the same time, the surface topography of HM-pectin waschanged from filament structure to tight curls. After DHPM-treated, it was found thatthe corresponding of particle size and lower molecular weight decreased ofHM-pectin, whereas the relative amount of reducing sugars decreased with theconcentration of ethanol increased from0%to10.0%. At the same time, the surfacetopography of HM-pectin was changed from filament structure to loose layerstructure. The degree of degradation of HM-pectin induced by DHPM reduced withthe concentration of ethanol increased from0%to10.0%. The mechanism ofethanol solvent for DHPM-induced degradation of HM-pectin comes from the ruptureof glycosidic bond, and may also occur to demethoxylation and elimination reaction.