Blueberry Intelligent Packaging Freshness Indicator Research

Intelligent packaging freshness indicators cause significant changes in the packaging indicators(such as color change,diffusion,etc.)by producing characteristic color reaction,temperature-activated biological reaction or enzymatic action between a characteristic gas and a specific reagent in food packaging during processing and circulation.It has the function of detecting food quality and perceiving food freshness without destroying food packaging,so as to provide food quality information on its own initiative.In this paper,the high-value berry"Lanfeng" blueberry was used as the research object,and the blueberry freshness indicator was developed with CO2 as the characteristic gas in the blueberry packaging.By measuring and analyzing the relationship between the respiration intensity of blueberry fruit and various physiological indexes of fruit,the authors explored the manufacturing process of indicator and the Arrhenius equation model of blueberry quality factor and indicator response factor.Experimental verification analysis and theoretical model analysis consider the effect of indicators,and finally obtains an indicator-type intelligent package that accurately reflects the freshness of the blueberry.The weight loss rate,fruit firmness,soluble solids content(SSC),titratable acid(TA)content,ascorbic acid content,anthocyanin content,polyphenols of blueberry fruits were measured every 7 days under the condition of low temperature storage at 4?.Physiological and biochemical indicators such as oxidase activity and malondialdehyde content were explored to correlate these indicators with the respiration intensity of blueberry fruit.The results showed that the respiration intensity of blueberry fruit was significantly positively correlated with malondialdehyde content,and it was significantly negatively correlated with fruit firmness and ascorbic acid content.Respiratory intensity could express the quality of blueberry.Through single factor experimental analysis and orthogonal test analysis,the indication effects of methyl red-bromothymol blue as two freshness indicators of dyeing solution and blueberry anthocyanin as dyeing solution were investigated.The study found that the maximum change of the color difference of the indicator of methyl red-bromothymol blue as the dyeing solution was 51.10;the maximum change of the color difference of the indicator of anthocyanin as the indicator liquid was 54.69.The comparison shows that the indicator preparation process using anthocyanin as the dyeing liquid is more suitable for blueberry fruits,regardless of the indication effect or food safety.In the process of establishing the kinetic model,the blueberry fruit hardness is used as the quality factor and the color difference of the indicator is used as the response factor.The Arrhenius equation model is used to solve the quality factor and response factor activation energy value of 61.816 kJ/mol,38.136kJ/mol,the difference between the two is within 25kJ/mol,so the indicator can play a variety of blueberry storage temperature.