Impact of Repeated Freezing and Thawing on the Quality of Goat Liver

Abstract

The present study investigated the effect of repeated freeze-thaw cycle, freezing at -20℃for whole night (12 hours) and then thawing at 4℃ for whole day (12 hours) on the quality of goat liver. For this purpose, raw fresh goat liver was collected and divided into five treatments groups- Day 1 (T1, fresh group), Day 2 (T2, freeze-thaw), Day 3 (T3, freeze-thaw), Day 4 (T4, freeze-thaw) and Day 5
(T5, freeze-thaw). Liver sample was packaged in polythene bags and frozen at -20℃ for overnight (12 hours) followed by thawing in refrigerator at 4℃ for whole day (12 hours). The freeze-thawed procedure was repeated for subsequent for four days. The sensory tests (color, odor, juiciness, and tenderness), the proximate components dry matter (DM), crude protein (CP), ether extract (EE) and ash, physicochemical properties (pH and cooking loss), biochemical properties free fatty acid (FFA%), Peroxide value (POV meq/kg) and Thiobarbituric acid (TBARS mg-MDA/kg), and the microbial assessments, total coliform count (TCC log CFU/g) and total yeast-mold count (TYMC log CFU/g) were carried out for each treatment. The result showed that color, odor, juiciness, and tenderness were significantly (p<0.05) decreased with the increase of freeze-thawed cycle. Dry matter and ash content were significantly (p<0.05) increased, whereas crude protein and ether extract were decreased with the increase of freeze-thaw cycle. pH was decreased and cooking loss was increased among different treatments significantly (p<0.05). Biochemical properties that was FFA%, POV and TBARS were increased significantly (p<0.05). Microbial assessments TCC and TYMC showed significantly (p<0.05) higher value with the increase of freeze-thawed cycle. From these findings suggested that shelf life of raw goat liver with repeated freeze-thawed cycle up to three days can kept with significantly changes of quality of liver are safe for human health.