Research On Gel And Digestion Properties Of Pectin-Starch Mixed System

This paper focuses on gel properties and digestive properties of starch-pectin system.The concentrations of pectin,sucrose and starch on the gel properties of the hybrid system is studied,and different structure and different amylose/amylopectin ratio of starch on the gel property and digestive properties of the hybrid system is also researched.The main conclusions of this paper are as follows:1.Dynamic rheological studies and the textural properties suggested that pectin in the absence of starch can't form gel in the in the coexistence of sucrose below 55%.Pectin can form gel while adding 3% starch,47% sucrose.Adding starch can significantly improve the gel properties of pectin.In static rheological studies,pectin gel remained pseudo-plastic fluids despite the presence of starch,and in the presence of starch,the mixed gel showed higher consistency coefficient K and lag ring area.Under the same gel strength,the in vitro digestion experiments of the pectin in the presence and absence of starch suggested that adding starch can reduce the amount of glucose of the HM pectin gel.2.The amylose and amylopectin were added in the pectin with the same amylose and amylopectin ratio of raw starch.Dynamic rheological studies suggested that the addition of starch in pectin would significantly improve the gel properties of the mixture,and gel state mostly depend on the properties of the pectin.The rheological and textural properties of pectin-starch with different structures suggested that the gel strength of pectin-AM/AP=2:8 is greater than pectin-raw starch.The Differential scanning calorimeter and low field nuclear magnetic resonance studies suggested that the water holding capacity of pectin-AM/AP=2:8 is also greater than pectin-raw starch.The mechanism of influence of starch in increasing the gel properties of pectin might be the swelling of starch granules lead the leakage of the amylose,and the crosslinking of amylose and pectin is formed,which lead an elastic gel.3.The amylose and amylopectin were added in the pectin with different ratios.Dynamic rheological studies suggested that as the proportion of amylose increased,the G' and G'' values of the mixed gel increased,the tan? decreased,and gave rise to better viscoelasticity.In static rheological studies,pectin gel remained pseudo-plastic fluids despite the presence of starch,and in the presence of higher proportion of amylose,the mixed gel showed higher consistency coefficient K and lag ring area,and lower fluid index n.The textural properties of the mixed gel were influenced by the proportion of amylose.With the increase of the proportion of amylose,the gel strength increased.Hydrogen bonding between pectin and starch might was a major physical force affecting gel texture as testified by adding urea.Gel in vitro digestion experiment results show that the gel system of glucose release rate as the amylose ratio rises,prefer to generate the index of hypoglycemia products.