Techniques to Improve the Quality of Chilled Seawater Preserved Indian Oil Sardine

Abstract- Chilling is a more economical and less energy intensive process than freezing, which preserves the intrinsic quality of the species before further processing and consumption. In order to improve the quality of pelagic fish preserved by the chilling method, the present study investigated the application of CSW and certain amelioration measures in chilled sea water (CSW) to improve keeping quality. The chilling system studied here were traditional icing (sample I), CSW chilling (sample C) and also CSW with aeration (sample CA) and CSW with CO2 bubbling (sample CC). The experiment was carried out in two stages. In stage-1 CSW held fish was compared with iced fish by estimating (on the basis of) physical, chemical, microbiological parameters. In stage-2 the CSW holding medium was bubbled amelioration/corrective measure to control anaerobic as well as air as an build up. The better chilling medium among the four treatments was aerated CSW sample. Spoilage indices like TVBN and TMA were significantly lower in sample of CSW with aeration (CA) and CSW with CO2 bubbling (CC) as compared to conventional CSW chilling (C) and chilling by ice (I). However, PV, FFA values for samples C, CC and CA did not show any variation. In CSW (sample C) beyond the 8th day there was anaerobic environment build up as shown by D.O depletion and H2S production. This resulted in higher anaerobic plate count (APC) for CSW sample C. Sample CC and CA showed lower APC. Total plate count was least for sample CC up to 5th day. Sensory evaluation for both raw and cooked samples covering attributes such as appearance, colour, odour and texture for raw, and odour, flavor and texture for cooked fish showed that CSW samples were more acceptable than iced sample, However, sample C exhibited higher quality through better scores for the first 7-8 days and sample CA with aeration kept good quality for longer period of 12-13 days as proven by the higher sensory scores. Both measures of amelioration to control anaerobic bacterial build up in CSW were successful with the finding that aeration is the best method of amelioration since it provides a longer holding period/storage life. Besides, aeration does not involve much additional cost as in the case of carbondioxide. Perhaps the power consumption of aerators is the only additional cost involved.