Quality and Shelf-Life of Cold Stored Mullet Fish (mugil Cephalus) Pretreated by Sorbate/Thyme Oil with Emphasis on Biogenic Amines

The effect of treatments of whole ungutted mullet fish (Mugil cephalus), by sorbate, thyme oil and their combination prior to cold storage (3-5 degrees C), on quality attributes, biogenic amines and shelf-life was followed. Microbial growth was significantly reduced during cold storage as a result of pretreatments. Protein deterioration reactions, lipid oxidation, and other chemical responsible for fish spoilage were also significantly decreased by pretreatments. Sensorial acceptability was improved by pretreatments with compared to control. The obtained data support each other and was confirmed by the sensorial evaluation. Moreover, a synergetic effect between sorbate and thyme oil was noticed, which prolonged the shelf-life of pretreated mullet fish, where combination of sorbate and thyme had a pronounced effect than that noticed for other pretreatments. Accordingly, shelf-life was prolonged to 11, 11 and 13 days for sorbate, thyme oil and thyme+sorbate pretreatments respectively, compared to 7 days recorded for control. Thyme+sorbate pretreatment is hereby recommended, since it has been found to keep cold mullet in wholesome state, extended shelf-life and ensure safe consumption of the mullet fish. The formation of biogenic amines in pretreated mullet was delayed and showed a fluctuation pattern throughout storage period. So, the presence of biogenic amines does not reflect a degree of spoilage, as well as their absence does not indicate higher quality level.