The Effect of Freezing Storage Duration on Physical and Chemical Properties of Pork Meat

Abstract

Regarding of inconsistency in texture of emulsion sausage made of some frozen pork batches found at the Livestock Development and Research Center, Chiang Mai, this paper aimed to investigate the effect of freezing storage duration on the meat’s physical and chemical properties and to specify a suitable storage duration. The fresh pork tenderloin was selected with similar size, color, and weight. Then washed with clean water and trimmed by separating only the red meat, each piece weighs about 500 grams, and packed in a zip lock bag. For 6 months, pork meat was stored at -40°C and sampled to analyse for its physical properties (color, texture, and microstructure) and chemical properties (pH value, moisture content, thawing loss, protein, and fat contents) each month. The results showed that the meat color changed from a bright red to a darker with paler red tone during the freezing storage. The freezing storage altered some texture properties of pork meat which demonstrated by a decrease of springiness and an increase of hardness and chewiness after 3 months. These also corresponded to the microstructure photos. The pH value of the frozen pork meat tended to increase until the 4^th month and slightly decreased thereafter. There was no difference in the moisture content between fresh and frozen pork meat while the thawing loss increased. In terms of protein, the detected amount seemed unchanged but the fat content decreased after 2 months. The overall analysis results implied some deteriorations of pork meat during frozen storage and suggested that the use of more than 3-month frozen storage should be avoided.