Investigating the effect of biodegradable calcium alginate coating incorporated with lactoperoxidase system in extending the shelf life of chicken breast during refrigerated storage

Abstract

Background and purpose: Apex of studies conducted about the edible coatings and films is related to 1980 to 1990 decade. However, this kind of coatings have more practical aspect at present era. Also the effect of lactoperoxidase enzyme as antimicrobial substance especially against gramnegative bacteria in milk has been proved long times ago. Thus, the present study investigated the impact of alginate coating incorporated with lactoperoxidase system (LPOS) on reducing the microbial and chemical spoilage of chicken breast fillet. Material and methods: In this experimental study, after preparation of edible alginate coating, lactoperoxidase system solution was added to coating solution in levels of 2, 4 and 6%. Finally, samples were treated and preserved in refrigerator for 16 days. During this period microbial, chemical and sensory evaluations were accomplished on the samples on days 0, 4, 8, 12 and 16 and the difference between the coated samples with the control sample (without coating) at the level of 95% was evaluated. Totally, 50 samples of chicken breast were investigated. Results: The results of chemical tests represented that these coatings (especially A-L 6), despite the effect on decreasing the formation of total volatile basic nitrogen (TVB-N) compounds (27.82 for control samples without any coating and 21.72 mg N/100 g for A-L 6 samples), had not significant impact on the lipolysis and the oxidation parameters. However, the LPOS- alginate coating introduced itself as a high antibacterial agent against Enterobacteriaceae, Pseudomonas aeruginosa and aerobic mesophilic bacteria (AMB), so that the difference of 4.61, 2.63 and 2.79 log between the samples of A-L 6 and control, respectively at the number of mentioned bacteria on the last day is considerable. Also, A-L 6 samples got the acceptable results by sensory panel. In this regard, general acceptability of A-L 0 and A-L 6 samples were 3.21±0.36 and 6.23±0.38, respectively on the last day which are significantly different (P < 0.05). Conclusion: It was shown that this type of coating didn’t play a major role on decreasing the rate of oxidation and lipolysis indexes. But they are caused theV impressive inhibitation on producing of TVB-N especially in higher levels of lactoperoxidase system. In association with microbial tests also alginatelactoperoxidase coating had lowering effect on growth rate of bacterial groups with the exception of lactic acid bacteria.