Combination effect of phosphate and vacuum packaging on quality parameters of Rutilus frisii kutum fillets in ice

Improving food quality among consumers is of high importance. This case in fish meat due to its quick spoilage is the more obvious. Therefore in this study in order to maintain and improve the quality of fish meat, effect of pretreatment with three different phosphate compounds including sodium tripolyphosphate (STPP), sodium pyrophosphate (PP) and mixture of them (STPP + PP) in combination with vacuum packaging (VP) on Rutilus frisii kutum fillets stored in ice was investigated. Phosphate pretreatment showed the synergistic effect with VP on reduction of psycrophilic bacteria, chemical and sensory deterioration of Rutilus frisii kutum fillets as evidenced by the lowered microbial counts, thiobarbituoric acid and total volatile base, compared with samples stored in air and those kept under VP. Pretreatment with PP resulted in the retarded protein denaturation as evidenced by the reduced changes in sulfhydryl content during the extended storage. Increase in water holding capacity accompanied by the decrease in pH was observed in samples pretreated with phosphates, especially tripolyphosphate. No marked autolytic degradation in samples kept under VP with and without phosphate pretreatment was observed throughout the storage as indicated by no changes in electrophoresis patterns. Determined shelf life based on psychrophilic bacteria counts for Rutilus frisii kutum fillets pretreated with STPP and stored under VP, until 15 days and according to sensory analysis until 12 days compared with samples stored in air. Therefore, the effective retardation of psycrophilic bacteria, chemical and sensory deterioration of Rutilus frisii kutum fillets stored under VP could be achieved by pretreatment with tripolyphosphate. (C) 2011 Elsevier Ltd. All rights reserved.