The Study On The Reason And The Control Of Green Discoloration On The Vacuum-Packaged Salted Goose

Salted goose is the tradition Chinese meat production which is favored by consumers because of its refreshing taste, tender meat, and rich nutrition. There was green discoloration on vacuum-packaged salted goose of some a factory in Yangzhou during storage. According to statistics, about20percent of salted geese get green discoloration after about one month. This abnormal color on the salted goose would reduce the sensory quality, and cause the economic loss to the manufacturers. In the study, the vacuum-packed salted geese which were produced by a large goose products company were as the research object. The reason of green discoloration and the control measure was preliminarily studied, which provide a theory basis for solution. The following were results of the study:1. The research on green discoloration of the vacuum-packed salt goose during storageThe microorganisms, water content, protein, nitrite, trace elements and fat oxidation on the green discoloration goose were analyzed. The results showed that there was no microorganism. And in the green group, the copper and iron contents respectively were8.3402±2.0275mg/kg and36.9981±8.7342mg/kg, the peroxide value was0.4722±0.054g/100g, all these were significantly higher than the normal samples. The green discoloration was correlated with copper and iron content and fat oxidation. It’s showed that the green discoloration on the salted goose was not due to microorganism, it might had relationship with the excess copper, iron and fat oxidation.2. Analysis of the copper and iron sources in the raw materials and the greening extractTo further find out the source of copper and iron in salted goose, the process water and the copper、iron content in the raw meat were analyzed, and the greening extract was preliminary studied. The results revealed that:the process water、curinging brine、cooking brine had no effect on greening discoloration. But the copper and iron contents of raw meat in the greening salted goose were higher significantly than the control group. The solution of75%acetone containing3%HCl had faded the greening substance effectively. There existed the metal-porphyrin pigments and free metals in the green epidermis.3. The inhibition effect of EDTA-2Na and carboxymethyl chitosan on the green discoloration in the salted gooseThe chelate ability of EDTA-2Na and carboxymethyl chitosan to Fe3+and Cu2+increased with the increasing concentration. The Fe3+chelating degree of carboxymethyl chitosan attained to49.45%, which was significantly lower than that of EDTA-2Na (96.57%) at the concentration1%; the chelation ratio of carboxymethyl chitosan to Cu2+was72.22%and there was no remarkable difference between EDTA-2Na and carboxymethyl chitosan. EDTA-2Na and carboxymethyl chitosan could significantly reduce the green discoloration rate and peroxide value, and the rate and value decreased with their concentrations increasing. At the same concentration, the EDTA-2Na and carboxymethyl chitosan had no significantly difference on the green discoloration rate. The samples containing the carboxymethyl chitosan were judged as more acceptable than control group. The difference of sensory between the samples with different carboxymethyl chitosan contractions was not observed. Though the chelate ability of carboxymethyl chitosan to metal iron was lower than EDTA-2Na, it had significantly inhibition effect on the green discoloration rate and peroxide value; In addition, the carboxymethyl chitosan had positive effect on the sensory quality.