Title: Development of a Quality Index Method (QIM) scheme for fresh cod (Gadus morhua) fillets and consumer acceptance

Final project
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Supervisors: Kolbrun Sveinsdottir


The aim of the study was to develop and evaluate a Quality Index Method (QIM) scheme for fresh cod (Gadus morhua) fillets and to study consumer acceptability of different cod products in comparison to a trained sensory panel.

QIM is an objective, rapid and reliable sensory method, based on well defined characteristic changes that occur in the deteriorative process of seafood. Demerit points are assigned to attributes and the resulting scores are summarised to give the Quality Index (QI). Cod fillets were stored at 0–1°C on ice up to 14 days. During storage, changes were observed and analysed using the QIM scheme for the raw fillets and Quantitative Descriptive Analysis (QDA) on cooked samples. In addition, total viable counts (TVC) and H2S-producing bacteria counts were done. As a result of this study, a QIM scheme for fresh cod fillets to evaluate freshness is proposed. A high correlation between QIM points and storage time on ice was found. The maximum storage time on ice determined by QDA of cooked fillets was found to be 8–10 days. Storage time could be predicted with an accuracy of ± 1.3 day. TVC and H2S-producing bacteria were at the limits of acceptability between seven and ten days of storage on ice.

Thirty-five consumers grouped as Icelanders and non-Icelanders participated in a consumer test using a nine-point hedonic test for overall liking, texture and flavour for three different cod products. A sensory panel evaluated texture, appearance, flavour and odour using the QDA method and the results of both tests were compared. The results showed that the sensory panel found differences between all the samples, whereas the consumers only found differences between unfrozen and frozen/thawed wild cod with a preference to fresh products.

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