Packaging Materials,Storage Temperature And Sterilization Treatment Influence Of Three Chinese Prefabricated Food On Their Quality

In order to ensure the safety and health of the prepared food and extend its shelf life,this experiment selected three Chinese prepared dishes:meat dishes(roast beef),vegetable dishes(agaric cabbage),and meat and vegetable combination(spicy cabbage streaky pork).The physical,chemical,microbial and sensory indexes were measured,and the effects of packaging materials,storage temperature and sterilization treatment on the quality of the prepared food during storage were discussed.The main results are as follows:Firstly,the effects of polyester/polypropylene packaging(PET/PP)and polyester/aluminum foil packaging(PET/AL)on the quality of three typical Chinese prepared dishes during storage were compared.The results showed that the L*value,b*value,hardness,springiness and chewiness of the three groups of samples decreased significantly(P<0.05)with the extension of storage days after different packaging treatments,and PET/AL packaging could maintain the color and texture characteristics of the samples to a greater extent than PET/PP packaging;Among them,the hardness of RB samples in PET/PP packaging group at the 9th day was5.33N,which was similar to that of PET/AL packaging group at the 6th day;The volatile components of the three groups of samples increased gradually with the extension of storage time,and the odor differences appeared on the 6th day of storage,the content of nitrogen oxides and aliphatic hydrocarbon oxygen-containing derivatives in PET/AL packaging group was lower than that in PET/PP packaging group;The lipid oxidation index and TVC value were positively correlated with the storage days,and the degree of fat oxidation in PET/AL was smaller than that in PET/PP packaging group(p<0.05).The TBA value of each sample in PET/PP packaging group had exceeded 0.5 mg MDA/Kg on the 12th day,and the TVC value was close to the critical value of health standard on the 9th day 5.0×10~4CFU/g and the sensory quality of the treatment group reached an unacceptable level at the 9th day,while the sensory quality of the PET/AL packaging group was unacceptable at the12th day.Secondly,after the samples were packed by PET/AL,the effects of normal temperature(25℃)and cold storage(4℃)on the quality of the samples during storage were compared.The results showed that the L*value,b*value,hardness,springiness and chewiness of the three groups were positively correlated with the storage days(P<0.05),and the cold storage environment was more conducive to the stability of the color and texture characteristics of the samples;The volatile components of the three groups increased gradually with the extension of storage time,and the odor differences appeared on the third day of storage,the contents of nitrogen oxides and low molecular amines in the cold storage group were lower than those in the normal temperature group;The TBA value,AV value,POV value and TVC value of the samples increased gradually with the extension of storage days(P<0.05),and the degree of lipid oxidation of the samples was more significantly delayed in cold storage than in normal temperature environment(P<0.05),The POV values of RB and SCS samples in the 25℃treatment group were 3.21 meq/Kg and 2.22 meq/Kg respectively on the third day of storage,and the TVC value of the cold storage group on the 12th day of storage was similar to that of the normal temperature group on the9th day of storage,on the 12th day,the TVC value of the normal temperature treatment group was close to the critical value of the hygienic standard,and the sensory quality had reached an unacceptable level,but the sensory quality of the cold storage group was still acceptable at the 12th day of storage.Thirdly,the three samples were pasteurized and ozone sterilized respectively,and then stored in cold storage(4℃)to compare the effects of the two sterilization methods on the quality of the samples during storage.The results showed that the L*value,b*value,hardness,springiness and chewiness of the three groups decreased significantly(P<0.05)with the extension of storage days,and the above indexes of the ozone sterilization group decreased more slowly than those of the pasteurization group(P<0.05);The L*value of RB samples in the pasteurization group at the 9th day was 43.27,which was similar to the L*value of RB samples in the ozone sterilization group at the 12th day.With the extension of storage time,the volatile components of the three groups of samples increased gradually,and the odor differences appeared on the 6th day of storage,the nitrogen oxides and organic sulfides detected in the pasteurization group were more than those in the ozone sterilization group;The lipid oxidation index and TVC value gradually increased with the extension of storage time.The AV value of RB samples in the ozone sterilization group at the 9th day of storage was 0.29 mg KOH/Kg,while that in the pasteurization group was 0.35 mg KOH/Kg.The fat oxidation rate of the ozone sterilization group was lower than that of the pasteurization group(P<0.05),and it could improve the microbial safety during storage;Sensory scores decreased significantly(P<0.05)with the increase of storage days,and the sensory quality of the two treatments was acceptable on the 12th day,but on the 9th day,the samples treated with pasteurization gradually released fat and juice,and the cooking taste was aggravated,while the samples treated with ozone sterilization could still maintain good quality on the 12th day of storage.