85328 - Quality Assessment of Fish and Fishery Products

Learning outcomes

Students will have to acquire a good command of the multi-faceted issue of fish quality (nutritional, functional, sensory, and freshness features), be the fish caught in the wild or farmed. Students will learn how to assess the quality of finfish and shellfish, intended either for direct consumption or for processing, through the use of instruments and, whenever possible, by sensory analysis. Students will also be able to critically evaluate information in the field of seafood quality and determine the relevance, authority and appropriateness of any given source.

Course contents

Since its beginning, more than twenty years ago, this course has been characterized by a high amount of practical work on finfish and shellfish around the so called "Five Qs", where Q stands for Quality, to be red as 1) Yields; 2) Nutritional quality; 3) Sensory quality; 4) Technological (functional) quality, and 5) Freshness quality.

All along the '19-20 academic year, so severe restrictions have been enforced as to practical work with students was concerned, that, in the end, it was necessary to give up the whole "package" entirely, which was a real pity, needless to say.

Now we do hope that "a return to normality" will ensue, in which case the following program will be proposed.

The concept of fish quality (consumer perspective, industrial perspective).

Yields. Dressing and filleting yields for the most important finfish, mollusk and crustacean species, either caught in the wild or farmed. Students will be challenged to find as many documents and videos as possible on this subject, the quality of which will be scrutinized just for the sake of exercise!

Nutritional quality. The Recommended Dietary Intakes of energy and nutrients for the Italian population (LARN, 2014) and the recently issued Guideline Daily Amounts (GDA). An exhaustive outline will be given as to the compositional characteristics of finfish and shellfish as naturally occurring functional foods. How finfish and shellfish fit human requirements for energy and nutrients, as well as the most widely known Food Guide Pyramids. Serving sizes and Index of Nutritional Quality for finfish and shellfish. Nutrition labelling of fishery products. Cooking-induced changes in compositional characteristics of finfish and shellfish. True and apparent nutrient retention coefficients. Fish and fishery products in food composition tables and databases.

Sensory quality. Basic principles. How do senses work? Recruiting, selection and training of panellists, keeping in mind normosensitivity tests. Discrimination tests. Descriptive sensory analysis. Recurrent errors in sensory analysis. An outline of consumer science (how to handle hedonistic responses). Sensory assessment of fish and fishery products as to colour, odour, flavour and texture.

Freshness quality. Post mortem changes in finfish and shellfish: how to tackle the intricacies of their description by chemical, physical and sensory methods. Quality Index Method (QIM): principles and critical evaluation of the main species-specific schemes.

Functional quality. Instrumental measurements of Liquid Holding Capacity (LHC), texture and colour of fish/shellfish flesh in order to support sensory evidence. Instrument - sensory relationships. The most important processing techniques applied to finfish and shellfish, special attention being paid to: 1) what makes a seafood raw material quite good at receiving any given processing technology; 2) which nutritional and/or sensory changes might occur in that raw material as a consequence of any processing technology applied

In case there exists serious interest within the students, towards the end of the lessons a new edition of the so called CIMENTO (the equivalent of the British word ordeal) could be issued. In brief, and on a voluntary basis, couples of students are expected to deepen one out of a list of selected topics, to be presented to their colleagues. In the past, there were clear signs that this additional task represented a welcome relief to the somewhat humdrum experience of sitting for examinations and taking grades home, although it implied a good deal of additional work.

Readings/Bibliography

Alasalvar C., Miyashita K., Shahidi F., Wanasundara U. Handbook of seafood quality, safety and health applications. Wiley-Blackwell, Chichester, West Sussex, UK, 2010.

Lie Ø. (Ed.), Improving farmed fish quality and safety, Woodhead Publishing Limited, Cambridge, UK, 2008.

Martinsdottir E., Sveinsdottir K., Luten J., Schelvis-Smit R., Hyldig G., Valutazione sensoriale della freschezza del pesce – Manuale di riferimento per il settore ittico, QIM-Eurofish, Svansprent ehf, Iceland, 2004.

Nollet L.M.L., Toldrà F. (Eds), Sensory analysis of foods of animal origin, Capp. 12÷17, CRC, Boca Raton, FL, USA, 2011.

Since finfish and shellfish came under our scrutiny as food items, occasional entries will be examined from the pages of the book by Rob DeBorde, Fish on a first-name basis: how fish is caught, bought, cleaned, cooked, and eaten, Thomas Dunne Books, New York, NY, USA, 2006.

Teaching methods

This course consists of formal lectures and supervised work, which involves how to perform:

- dressing and filleting of finfish, up to the preparation of flesh samples ready for nutritional analyses;

- a complete nutritional assessment of any given seafood as emerges from the most widely known databases (for labelling purpose)

-assessment of pH and Liquid Holding Capacity (LHC) in fish flesh;

- sensory and instrumental evaluation of colour in fish and fishery products;

- the most important discriminant tests in sensory analysis;

- freshness quality evaluation of farmed fish by physical (Fish Freshness Meter) and sensory methods (QIM).

N.B: students with special needs are kindly requested to contact the teacher by e-mail in order to explain them and to organize both lessons and examinations as best as possible.

Assessment methods

Within the examination “Seafood quality evaluation” (ValuQua in the following, 6 CFU), students have to take a 25-to-30-min. oral examination, during which they are expected to answer three questions related to seafood quality problems and how to prevent/solve them. These three questions will be drawn by each examinee out of a complete list, which will have been made timely available.

In details, here is the possible score grid for oral examinations which is my intention to adopt in the near future:

- a very thorough knowledge of the topics addressed in the course, together with high skills of critical analysis, connection and a sure command of specific terminology will be evaluated with the maximum score (30-30L);

- a thorough knowledge of the topics addressed in the course, together with good analytical and critical skills and the possession of a sure command of specific terminology will be evaluated with good marks (27-29);

- a technically adequate preparation and a sufficient analytical capacity, even if not particularly articulated, expressed in a correct language, will produce fair evaluations (23-26);

- sufficient preparation and capacity for analysis, expressed in a language which is barely formally correct, will determine the sufficiency (18-22).

In order to generate the overall mark related to the integrated course of "Instruments and senses towards seafoods quality" (IStSQ, 9 CFU), ValuQua examination will have to be complemented by "Biochemical Basis of Seafood Quality" (BBSQ, 3 CFU). The overall mark will be obtained through weighting as exemplified in the following.

For instance, suppose Philip had taken the following marks: ValuQua 27/30 and BBSQ 24/30. Well then,the overall mark will be: [(27*6) = 162] + [(24*3) = 72] = 234/9 = 26,00 and this will be the end of it.

 

 

Teaching tools

Videoprojector, PC, laboratories.

Office hours

See the website of Anna Badiani