Optimization And Application Of Meat Freshness Indication Packaging Containing Anthocyanins

In the process of storage,under the action of microorganisms and enzymes,the quality of cold chicken decreases,and finally deteriorates and becomes inedible.At present,indicator film based on natural product anthocyanin(ATH)has been widely concerned in meat freshness indicator.Using anthocyanin as an indicator film,the freshness of meat can be judged by the color change of the indicator film,which has the advantages of convenience and speed.There was no significant difference in the color response of anthocyanins from a single plant near neutral pH value.As a natural flavonoid,the chemical properties of anthocyanins are extremely unstable.Under the action of environmental factors such as light,temperature and pH,anthocyanins are easily degraded.In addition,the indicator film containing anthocyanins at the present stage is easy to dissolve from the indicator film in a high-water environment,which affects the accuracy of the indicator film.Therefore,in this thesis,purple cabbage,mulberry and purple potato were used as raw materials to extract anthocyanins,explore the pH color response of anthocyanins in different proportions,and select the optimal complex ratio.Anthocyanins were co-colored with ferulic acid,gallic acid and protocatechuic acid to investigate the stability and color response of anthocyanins under ultraviolet light.On this basis,carboxymethyl cellulose(CMC)and sodium alginate(SA)were used as substrates to prepare indicator films,and the basic properties of indicator films were studied and applied in chicken freshness indicator.The main conclusions are as follows:1.Anthocyanin compound and ultraviolet stability studyThe color difference results showed that the color response of anthocyanins combined with purple cabbage and mulberry(9:1)was the most significant.The results of Fourier transform infrared spectroscopy of anthocyanins showed that hydrogen bond could be formed between purple cabbage and anthocyanins extracted from mulberry.The results of ultraviolet spectrum scanning,color difference and pH response showed that ferulic acid,gallic acid and protocatechuic acid could co-coloration with anthocyanins,improve the stability of anthocyanins under ultraviolet light,reduce the degradation of anthocyanins,and maintain the unique color and pH color response ability of anthocyanins.2.Preparation and performance study of anthocyanin/sodium alginate/carboxymethylcellulose membraneThe anthocyanin dissolution rates were 29.9%,24.1%,20.7% and 20.0% for different carboxymethyl cellulose(0%,0.1%,0.3% and 0.5%)indicator films.There was no significant difference in ΔE values between different CMC content indicated films.When CMC was added to the membrane,the water vapor transmittance and elongation at break of the membrane were increased,and the toughness of the membrane was enhanced.Fourier infrared spectroscopy results show that with the increase of CMC addition,the hydrogen bonds formed between biopolymers also increase,which is related to the hydrophilicity of CMC.3.Research on the application of anthocyanin-based indicator membrane in chickenStored at 4 ℃ for 8 days,the TVB-N value,pH value and TVC of chicken showed an increasing trend with time.On the 6th day,the TVB-N and pH value exceeded the limit value and spoilage occurred.The color change of the indicating film is obvious,and the color of the indicating film is yellowish green on the 6th day.ATH-SA-0.3CMC indicated that the Pearson correlation coefficients between ΔE values and TVB-N,pH and TVC values were the highest,which were 0.97,0.988 and 0.959,respectively.The results of GC-MS showed that 49 kinds of gases were detected,including nitrogen compounds,hydrocarbons,esters,ethers,acids,alcohols,aldehydes,ketones and sulfur-containing compounds.Trimethylamine,indole,1,1-dimethylhydrazine,m-aminophenacetylene,butyric acid,4-methylvaleric acid,S-methyl2-methylthiopropionate,methylmercaptan caproate,S-methyl thiopropionate,n-propyl propionate,S-ethyl mercaptan isovalerate,and propyl acetate were not detected in the samples containing indicator films.