The Study And Production Of Freshness Indicator Card Applied To Modified Atmosphere Packaged Chilled Pork

Chilled pork with rich nutrition, good taste, health and safety, become a new consumption pattern. As the chilled pork is susceptible to microbial contamination and environmental impact of transportation, it has short shelf life. At present, in respect of chilled pork preservation, the combination of preservation and the way of packing is used in prolonging its shelf life. And the way of packing given greatest attention is modified atmosphere packaging. However, the shelf life of modified atmosphere packaged chilled pork is uneven as cold-chain systems in most companies are imperfect, leading to microbial rapid proliferation, and initial state of modified atmosphere packaged chilled pork is also different. Moreover, consumers can not directly contact with the packaged meat, so it is difficult to determine its freshness through the method of sensory evaluation.This paper selected 14 kinds of acid-base indicator, according to the nature of the volatile substances from chilled pork, used to study their color variations during chilled pork corruption, and determined the chromogenic agent whose color variations could reflect the freshness difference of chilled pork in the process of corruption effectively. And, corruption time of chilled pork was determined by measuring main quality indexes and reasonable mathematical statistics analysis. Optimization experiment was used to obtain the best amount of methyl cellulose, chromogenic agent and the p H of indicator card, which were key points in making indicator card.The results showed that:(1) By comprehensive evaluating the quality indicators, it was concluded that the total number of bacteria, TVB-N, p H, S2, S6 and S7, S8 and ind1-ind14 had strong relationships and could reflect the freshness of packaged chilled pork. In this analysis, bromocresol green was selected to reflect the quality change effectively in the process of pork corruption.(2) By comparing the rate of color change of freshness indicator card and the speed of pork corruption, as well as the correlation analysis between the indicator card’s color change and TVB-N of pork, it was concluded that the amount of three factors(methyl cellulose, chromogenic agent and p H of indicator card) could affect the indicative sensitivity of that card under the condition of 5℃ and 10℃.(3) By the experimental design of the software named Design-Expert8.0.6, optimum technology parameters of freshness indicator card for chilled pork were gotten: methyl cellulose dosage 2.81 g, chromogenic agent 3.94 m L, the initial p H of indicator card 1.79. The indicator card under this condition of these preparations had the highest goodness-of-fit(R2) with TVB-N and the minimum time difference of color change(△T).(4) Through the experiment, freshness indicator card could indicate effectively the freshness of chilled pork packaged MAP with laboratory optimizing gas ratio and common gas ratio used in enterprises at the temperature range from 8℃ to 20℃.Feature maps and style applied were also gotten.