Effects Of Apple Polyphenols And Low Ester Pectin On Its Physical And Chemical Properties, Antioxidant Activity And Microstructure Under Different Chemical Conditions

Low ester pectin has attracted more and more attention and been applied in more and more fields due to its advantages such as wide p H range,low requirement for soluble solid content and good gel performance.Due to its good emulsifying,gelling and hydraulic properties,low ester pectin is often used as food emulsifier,gelling agent and quality improver.Apple polyphenols are widely used in the field of medical and health products and food antioxidants in recent years due to their easy availability of raw materials and excellent physiological activities such as scavenging free radicals,anti-cancer,anti-aging and anti-radiation.PH,calcium concentration,sucrose concentration and polyphenols in the food system have different effects on the gel performance and antioxidant activity of low-ester pectin.In this paper,citric acid,sodium citrate buffer solution to adjust p H value,with Ca Cl2 adding amount regulating calcium ion concentration,with sucrose content mock the existence of the soluble solids in the food system,add to the low ester pectin gel system of apple polyphenol and polyphenols in common: two monomers belongs to flavonoids and phenolic acids of root bark of chlorogenic acid,to explore the p H,calcium ion concentration,the concentration of sucrose and polyphenols added amount of low ester pectin gel properties and the effect of antioxidant activity.Three polyphenols and low ester pectin compound systems were prepared: apple polyphenol-low ester pectin compound gel(AP-LMP),root-bark glucosinol-low ester pectin(P-LMP)and chlorogenic acid-low ester pectin(CA-LMP).Under the conditions of the same p H,calcium ion concentration,sucrose concentration,polyphenols and low ester pectin concentration,turbidity of the system: P-LMP > AP-LMP > CA-LMP,hardness,elasticity,adhesion and other sensory characteristics: P-LMP > AP-LMP > CA-LMP,antioxidant capacity: CA-LMP > P-LMP > AP-LMP.Under the same conditions of calcium ion concentration,sucrose concentration,polyphenols concentration and low ester pectin concentration,the gel system formed at p H 4.2 has the highest turbidity,hardness,elasticity and stickiness,the highest energy storage modulus and loss modulus,the lowest loss tangential value,and the strongest gel strength.PH increased from 3.0 to 6.0,and the antioxidant strength of AP-LMP,P-LMP and CA-LMP gel systems increased accordingly.When p H,sucrose concentration,polyphenols and low ester pectin concentration are the same,when Ca Cl2 concentration is 45-55 mg,the system has higher turbidity,better hardness,elasticity and adhesive viscosity,higher adhesive elasticity and gel strength.The antioxidant capacity of AP-LMP and P-LMP systems decreased slightly with the increase of Ca Cl2 concentration,and the antioxidant capacity of CA-LMP systems decreased significantly.Under the conditions of the same p H,calcium ion concentration,polyphenols and low ester pectin concentration,sucrose concentration has a great influence on the viscosity of AP-LMP,P-LMP and CA-LMP gel systems,and the viscosity of the system increases with the sucrose concentration.After the addition of polyphenols,the microstructure of low-ester pectin was observed,and it was found that polyphenols could make the microstructure of low-ester pectin more orderly and compact.