Effects Of Different Binding Conditions On The Properties Of Pectin And Anthocyanins Of Aronia Melanocarpca Conjugates

Aronia melanocarpca Elliot,also known as Aronia,has potential health benefits due to its anthocyanin content.In the process of processing and storage,anthocyanins are easily hydrolyzed and opened,resulting in changes in color and functional degradation.At present,studies have shown that anthocyanins can be combined with pectin to form a conjugate to improve its stability and prolong its half-life.However,little research has been done on the binding effect of external factors and the physical and chemical properties of the conjugates.This experiment mainly explored the effects of external factors on the binding of anthocyanins with pectin,chemical properties?antioxidant capacity,thermal stability,simulated gastrointestinal digestive stability?,physical properties?chemical bonds and microstructures?of conjugates,and the binding of anthocyanins.To provide theoretical and data support for the protection of anthocyanins in related products of Aronia melanocarpca.The main findings are as follows:?1?The single factor results showed that the pH value of the solution and the pectin addition had a significant effect on the binding rate.The addition of Ca²⁺inhibited the combination of these two,and the addition of Mg²⁺and carbohydrates had no significant effect on the binding rate.The highest binding rate was 78.77%when the solution pH was 3.0 and the anthocyanin to pectin addition ratio was 1:2.0.?2?The pH value of the solution will affect the antioxidant activity(·OH scavenging ability,ABTS⁺·scavenging ability and Fe³⁺reducing ability)of the conjugates;anthocyanin-pectin conjugates produced in low pH solution has higher antioxidant activity.With the increase of pectin content,the antioxidant activity of anthocyanin-pectin conjugates decreased.It is speculated that pectin may first interact with phenolic hydroxyl groups on anthocyanin during the binding process.?3?The stability of anthocyanin-pectin conjugates produced in lower pH solution environment is stronger in thermal and gastrointestinal environment,which indicates that the structure of anthocyanin-pectin conjugates is tighter in lower pH solution environment,and pectin can slow down the rapid degradation of anthocyanin in high temperature and alkaline environment.?4?The anthocyanins of Aronia melanocarpca are composed of cyanidin-3-galactoside?C3Gla?,cyanidin-3-arabinoside?C3Ala?,cyanidin-3-xylose?C3Xyl?and cyanidin-3-glucose?C3Glu?;the binding of C3Gla and C3Ala to pectin is similar;the binding rate of C3Glu and C3Xyl to pectin is similar,and the binding ability of C3Xyl to pectin is the weakest.The reason for this may be that the binding strength of anthocyanins to pectin is not only related to the number of hydroxyl and methoxyl groups of anthocyanins,but also to the type of anthocyanins and their glycosyl configuration.Infrared analysis shows that the hydrogen bond and the interaction between ions are the main forms of non-covalent binding of anthocyanins to pectin.The ionic bond of the conjugates are formed by the carboxyl group of anthocyanin molecule,the C-H bond of phenol hydroxybenzene ring and the carboxyl group of galacturonic acid in pectin molecule;pectin has an embedding effect on anthocyanins in the formation of the conjugation.The pH value of the solution will affect the roughness of the morphological surface of the conjugates,and the addition of pectin will affect the hardness and the degree of dispersion and fragmentation of the composite particles.The results showed that controlling the degradation of anthocyanin in vitro and improving its bioavailability could be achieved by adjusting the pH value of the solution.This method can effectively extend the range of use of anthocyanins.