The team of Professor Chen Xiangning of our Bet365 games has made new progress in the field of preparation of highly sensitive intelligent packaging materials

Recently，Professor Chen Xiangning’s team from the Key Laboratory of Agricultural Products Processing and Quality Control of the Ministry of Agriculture and Rural Affairs of our Bet365 games published an authoritative publication in the food field "Food Hydrocolloids" (District 1, Chinese Academy of Sciences)，IF=11.0) published an article titled "pH-responsive color indicator film based on gelatin/chitosan cross-linking with anthocyanin-Fe2+ chelate for pork freshness monitoring" (based on gelatin/chitosan and anthocyanin-Fe2+ Research paper on chelate cross-linked pH-responsive indicating membrane - real-time monitoring of the freshness of chilled pork。This study uses cross-linking polymerization and various characterization techniques，In-depth discussion of the stability and color response properties of anthocyanin-Fe²⁺ chelates in gelatin/chitosan matrix，Smart film prepared using natural anthocyanins shows high sensitivity to ammonia gas and pH changes generated during the refrigeration process of meat。Through the cold fresh pork preservation experiment，Verified that the smart film can effectively monitor the degree of spoilage of meat during storage by indicating the color change of the film，Achieved without opening the package，Intuitively judge the quality of meat，Provides an innovative solution for monitoring the freshness of chilled pork。

Studying the hydroxyl groups through the chelate and the hydroxyl groups in the cross-linked matrix、Hydrogen bonding between the amino group and the ester group realizes the binding of the anthocyanin indicator to the film matrix。FTIR spectrum display，The addition of citric acid leads to changes in the characteristic absorption peaks of the amide I and amide II bands of the matrix，Formed Bet365 games ester bonds and hydrogen bonds with BG and CS。XRD analysis further confirmed that the developed pH smart indicating film is chemically structurally compatible with the matrix，And the hydrogen bonding between blueberry anthocyanin-iron chelate (BA-Fe²+) and the matrix helps maintain the three-dimensional network structure of the film，Enable the smart indicator film to have better stability。

Structural changes of BA and BA-Fe2+ after combining with matrix

Research shows，Interaction between the addition of BA-Fe2+ and other components in the membrane，Improves the stability of the membrane under high temperature conditions and increases the density of the membrane，Make the penetration path of water molecules more tortuous，Thereby reducing water vapor permeability (WVP)。The addition of BA-Fe2+ improves the membrane’s oxygen barrier (OP)，Protect pH indicator from oxidation，At the same time, the indicator film also has certain antioxidant and antibacterial activity。

Comparison of surface roughness atomic force microscope images of films with different components

Color changes and sensitivity comparison of films with different components in ammonia vapor

Research Discovery，Affix the smart pH indicator film to the packaging box containing fresh pork，Place in refrigerator at 4°C。As time goes by，The indicator film changes from rose red to deep red，Then gradually changes to purple and blue。Purple prompt early corruption warning，Further transformation to blue indicates that the meat is no longer suitable for consumption。This display result is consistent with the quality evaluation results of fresh pork (pH value、TVB-N value and quality loss, etc.)。This smart film determines the degree of spoilage of cold fresh pork by indicating the color change of the film，Provides a Bet365 games solution for monitoring the freshness of pork。

Zhao Haolan, a master’s student in the Bet365 games of Food Science and Engineering, is the first author of the paper，Professor Chen Xiangning、Dr. Zhang Hongru is the corresponding author of the paper。Professor Chen Xiangning said，The team will thoroughly study and implement the spirit of the Third Plenary Session of the 20th CPC Central Committee and the spirit of the National Education Conference，Comprehensively implement the spirit of the Bet365 games’s Fourth Party Congress，Continuously improve technological innovation capabilities，Produce high-level scientific research results，Improve the quality of independent talent training，Making new and greater contributions to accelerating the construction of a domestic first-class and internationally renowned urban agricultural and forestry characteristics high-level application-oriented university。