Sensory, microbiological and chemical changes in hoki stored in ice

Abstract

Sensory, physical, microbiological and chemical analyses were carried out on whole hoki during 21 days of storage in ice. Sensory results show that cooked hoki developed unpleasant odours and flavours after 11 days. Texture changes in cooked fish were minimal. Assessment of the raw fish provided a useful means of predicting quality of cooked fish. The total viable aerobic count on the fish surface first exceeded ICMSF standards after fish had been stored for 11 days in ice. Hypoxanthine and K value were good objective indicators of the freshness of hoki, while measurement of trimethylamine provided a means to monitor the onset of spoilage. et al.methods. Useful objective methods of assessment for cooked hoki quality were also determined. The experiment used fish caught in the main catching season and location to represent the majority of hoki landed in New Zealand. Materials and methods FishHoki were caught off the northwest coast of the South Island during the spawning season for hoki. This is the main area and peak catching season for hoki in New Zealand. The fish were caught at a depth of 505 m at Latitude 41'23's and Longitude 17W41'E by bottom trawling. The fish were taken from the deck immediately and packed into polythene lined polystyrene cartons with an equal volume of ice. Twenty fish were frozen to -30°C to be used as a reference sample for sensory analysis of cooked fish. The fish were transported to our laboratories and were less than 2 days in ice on arrival. They were then placed in an insulated container at an ambient temperature of 4°C. The ice : fish ratio of 1 : 1 was maintained throughout the trial. Sampling protocolThe fish were sampled immediately after catching and on days 2, 4, 6, 8, 11, 13, 15, 18, and 21. At each sampling time, ten whole fish were removed from the ice for evaluation. Five fish were used for microbiological analyses. When needed, one fillet from three of these fish was set aside for sensory assessment of the cooked flesh. The other five whole fish were used for determination of the physical characteristics and sensory assessment of raw fish. One skinned fillet from each of these fish was put in an individual plastic bag and frozen at -30°C to await chemical analysis. When needed, the other fillet from each of these fish was set aside for sensory assessment of the cooked flesh, making a total of eight fillets for this purpose. Physical characteristics and proximate analysisEach fish was weighed, sexed, and the length measured. Five fish were removed after being stored for 2 days in ice for determination of protein, ash, oil and moisture (Vlieg, 1984). Sensory analysesRaw fish. The fish were examined for changes in appearance and odour. This included description of the eyes, surface, gills, and fillet. Each fish was assessed by at least two people experienced in fish quality evaluation. A demerit point scoring system (Bremner ef at., 1987) was also used. This system assigns demerit points to general appearance and to the state of rigor, eyes, gills, surface and belly. This ...

Quality assessment of Mediterranean horse mackerel (Trachurus mediterraneus) and blue jack mackerel (Trachurus picturatus) during storage in ice

“…However, as high cell concentrations of 10 8 -10 9 cfu/g of SSO are normally required to cause spoilage of ice-stored Wsh (Gram & Huss, 1996;Huss et al, 1997), it was assumed that these organisms were not major spoilers in the present study for both Wsh species. Our results are similar to results from other storage trials on iced whole Wsh (Lougovois et al, 2003;Paarup et al, 2002;Ryder, Buisson, Scott, & Fletcher, 1984;Ryder, Fletcher, Stec, & Seelye, 1993;Scott, Fletcher, Charles, & Wong, 1992;Scott, Fletcher, Hogg, & Ryder, 1986). An average level of 10 6 cfu/g of SSO would be probably indicative of marginal quality Mediterranean horse mackerel and blue jack mackerel.…”

Use of sterile and ozonized water as a strategy to stabilize the quality of stored refrigerated fresh fish

“…Such methods must delay fish alterations. It would allow good quality fish to reach retail points of sale (Dosti, Guzel-Seydim, & Greene, 2005;Kim, Yousef, & Dave, 1999;Pastoriza, Bernárdez, Sampedro, Cabo, & Herrera, 2004;Ryder, Fletcher, Stec, & Seelve, 1993;Silva da, Gibbs, & Kirby, 1998 There is a large body of studies dealing with the loss of fish quality, but the problem still exists (Huidobro, Mendes, & Nunes, 2001;Khadre, Yousef, & Kim, 2001;Lougovois, Kyranas, & Kyrana, 2002;Pedrosa-Menabrito & Regenstein, 1990). Most studies are pilot-plant experiments and do not sort out the problems taking place in fishing boats.…”

Lipid Oxidation of Catfish (<i>Arius maculatus</i>) after Cooking and Smoking by Different Methods Applied in Cameroon

“…Processing has been known to affect the chemical composition and fatty acids of fish. Several workers have linked the availability of vital nutrient of fish to the method of storage [13,14]. Storage time and temperature are the major factors implicated in the loss of quality and shelf life of fish [15].…”