Study On Time-Temperature Indicators For Cold Chain Packaging Of Raspberry

In cold chain logistics transportation,the temperature abuse of refrigerated food is a frequent problem.When food is exposed to an environment higher than the required temperature during distribution and storage,it will promote the growth of spoilage microorganisms and foodborne pathogens This is a great challenge to product quality control,which seriously affects the quality and safety of food.Time temperature indicator(TTI)is a simple,effective and easy-to-use device for monitoring,recording and accumulating the change in the quality of food from transportation to the final consumer.TTI is part of food packaging.Most devices allow consumers to check food quality through a color response that matches or correlates with the quality of food at a certain temperature.In this paper,mangosteen fruit is taken as the research object to study its physiological and biochemical characteristics and correlation analysis.TTI was prepared by using natural degradable material starch and polyvinyl alcohol as indicator substrates and adding functional indicator component purple cabbage anthocyanins.The effects of film-forming substrates and functional additives on the performance of TTI were investigated.After kinetic modeling and system analysis,they were used to monitor the quality changes of mangosteen fruit.The research of this topic mainly includes:The quality changes of red raspberry fruit stored at different temperatures(1℃,4℃,10℃)were studied.It can be seen that low temperature(1℃)storage has a significant effect on improving the quality indexes of red raspberry.Correlation analysis showed that there was a significant correlation between respiratory intensity and weight loss rate,decay index,and malondialdehyde content,and a decay index was extremely significantly correlated with malonaldehyde content,which was significantly correlated with weight loss rate and polyphenol oxidase activity.The optimum extraction conditions of purple cabbage anthocyanins were determined by orthogonal experiment.At the same time,the stability of purple cabbage anthocyanins under temperature,pH value and light was analyzed.The results show that the lower the temperature,the higher the stability of anthocyanins;purple cabbage anthocyanins exhibit significantly different color changes at different pH values;long-term light will accelerate the oxidative decomposition of anthocyanin structures,so it should be stored protected from light.A time temperature indicator was prepared useing starch,polyvinyl alcohol and purple cabbage anthocyanins as raw materials.The xperiment shows that compared with the control group,the blend has good compatibility due to the presence of anthocyanins,and the indicator has better mechanical properties.In addition,the indicator exhibits different color changes under different pH conditions,and has a good response to changes in pH.TThe kinetic parameters of red raspberries and time and temperature indicators were studied and analyzed.The activation energies of the two reactions were 51.147kJ/mol and 71.105kJ/mol,respectively.Through matching analysis,the difference between the two activation energies was less than 25kJ/mol,so the time temperature indicator can accurately monitor red raspberries.The shelf life of the fruit is indicative of quality changes during cold chain transportation of red raspberries.