Study On Extraction And Functional Properties Of Pea Soluble Polysaccharide

In this study,pea soluble polysaccharide(PSPS)with functional properties was extracted from pea by-product by using enzyme-assisted acid extraction.The PSPS-A and PSPS-B obtained by spray-drying and ethanol precipitation/oven drying were characterized include molecular mass,characteristic functional group and zeta-potential,rheological properties,microscopic morphology,and their application as addition agent in acidic milk beverages and emulsions,which controlled by soybean-soluble polysaccharide(SSPS).The results of the study are as follows:(1)The optimum technological condition of enzyme-assisted acid extraction by single factor experiment is as follows: 0.24% amylase with reaction time 30 min,0.15% Viscozyme L with reaction time 30 min,deproteinization time 30 min.Under the above conditions,the yield of PSPS was 10.43% with great dispersion stability.(2)The physicochemical composition,functional groups,molecular weight,particle size distribution,Zeta potential,rheology,and microscopic shape of PSPS-A and PSPS-B were characterized by means of basic physicochemical analysis,Fourier transform infrared spectroscopy,gel-filtration chromatography(GPC),Zetasizer Nano-ZS instrument,rheometer and atomic force microscope,respectively.PSPS is an anionic polysaccharide with a characteristic absorption peak of polysaccharides,and has a multi-side chain structure similar to SSPS;from the molecular weight point of view,the weight average molecular weight of PSPS-A,PSPS-B and SSPS are 625 k Da,810 k Da and 687 k Da,respectively.The zeta-potentials absolute value of PSPS-B is higher than PSPS-A and SSPS between p H 2-11.With 5% concentration,the viscosity of PSPS-A,PSPS-B and SSPS solution is 10 m Pa.s、13 m Pa.s and 14 m Pa.s,respectively,which indicating PSPS is a low-viscosity polysaccharide.(3)PSPS-A,PSPS-B and SSPS were added as stabilizers to the formulated and fermented acidic milk beverages respectively.The average particle size,precipitation rate,Zeta potential,viscosity and microscopic distribution of the milk beverage were being the indicator of their stability,the effect of the addition amount and p H on the stability of the milk beverage was studied.Experiments show that PSPS-A,PSPS-B and SSPS can stabilize casein under acidic conditions,and can be applied to both formulated acidic milk beverages and fermented acidic milk beverages to obtain less viscosity and smooth taste.For formulated milk beverages,adding 0.1% PSPS-B or SSPS at p H 4.0 is sufficient to prevent protein precipitation from forming a stable system,whereas PSPS-A requires 0.15%addition to achieve the same stabilization effect.In the presence of 0.15% stabilizer,PSPS-B has the widest stability range(p H 3.6-4.6),followed by PSPS(p H 3.6-4.4),and SSPS has the smallest stable range(p H 3.6-4.2).For fermented milk drinks,adding 0.4% of PSPS-B or SSPS at p H 4.0 is sufficient to cover the surface of casein to prevent protein aggregation and form a stable system,while PSPS-A requires 0.5% addition to achieve the same stabilization.In the presence of 0.5% stabilizer,a good stable state can be achieved ranged from p H 3.4 to 4.2.(4)Using PSPS-B and SSPS as emulsifiers to stabilize the emulsion.The effects of emulsifier concentration(2-6%),p H(3.0-7.0),salt ion concentration(0-100 mmol/L Na Cl)and heat treatment(30-90°C)on the stability of the emulsion were systematically studied.The stability of the emulsion increases as the polysaccharide concentration increases,and 4% PSPS-B or SSPS can achieve a more stable effect.At this concentration,p H,ionic strength,and thermal treatment have little effect on the emulsions stability of PSPS-B or SSPS.