Effects of frozen storage and organic acid solution dipping treatment on the quality of Sarawak raw fish salad (umai) from red tilapia

H.P. Chua* and K. Saniah*

Abstract

A study was conducted to evaluate the possibility of extending the shelf life of freshwater red tilapia umai stored by combination of frozen and dipping treatment in aqueous solution containing food-grade organic acids. The implications of applying these treatments were measured by physical, chemical, microbiological and sensory evaluation. The results showed that at least 60% of the panellists indicated that fillet samples frozen at –23 °C for 7 days were equal or better than the fresh samples for all the sensory attributes evaluated. Shelf life of chilled umai cutlets increased when they were treated with dipping solution containing organic acid (citric acid, lactic acid and acetic acid) with pH fixed at 4. Samples treated with dipping solution 1.5% citric acid gave the best storage quality in terms of total aerobes count and colour intensity. Control samples and samples without organic acid treatment were considered spoiled after 8 days of storage with total volatile base nitrogen value (TVBN) and total aerobes count exceeded or close to the limit of acceptability.

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