85909 - EVOLUZIONE SENSORIALE DEI PRODOTTI ITTICI DURANTE LA CONSERVAZIONE

Learning outcomes

SENSORY CHANGES in FISH and FISH PRODUCTS along the STORAGE

Learning outcomes

At the end of this course, students will have implemented all the usual tests of “normosensitivity”, as necessary and preliminary steps. Moreover, they will have either acquired or refreshed:

• the fundamentals of sensory analysis in general, as well as that part of this discipline which relates to seafood products, having already dealt with the chemico-physical and microbiological changes which finfish and shellfish flesh undergoes during storage (see the contents of the 85908 course (*), whose lectures are given in the first half of the second semester, still within the third year of this degree course);

• a clear perception and understanding of what a “normal” shelf-life evolution is whenever applied to finfish and shellfish, as compared to an abnormal evolution, be the product under examination the result of either simple refrigeration, or frozen storage, or having being dried, salted, canned, smoked, etc (the focus of our interest being the most popular way of preserving seafoods).

Course layout

This course will be organized in 7 three-hours lectures, starting from the second week of April (Easter vacation allowing), this level of concentration being suggested by the necessity to have the theory side by side with practical work, whenever possible.

A side-note must be given at this very spot: a good deal of the actual layout of this optional course will be decided taking into account the level of attendance of both lectures and practical work. The approach suggested in the following lines probably is one of the most ambitious.

Course contents

Course introduction, with layout and aims. Suggested text books as well as sound web sources of information. Explanations will be given as to how the examination will be conducted and the final score given (i.e. as the arithmetic mean between this very score and the other one (*).

The main features of sensory analysis as applied to finfish and shellfish and as explained quite in detail within the course by the title “Seafood quality evaluation and food technology”, which comes the previous semester and should have been passed beforehand.

Normosensitivity trials as to colour and texture: theory and practice, with immediate evaluation of the results obtained.

Normosensitivity trials as to odour, basic taste, flavor, mouthfeels, aftertastes and afterflavours: theory and practice, with immediate evaluation of the results obtained. Wrapping it up the overall outcomes of the sensitivity trials. There are much more than a simple meaning for the expression “shelf-life”, in the interpretation given by Barbosa, Bremner and Vaz-Pires (see Bremner, 2002), a concept recently and duly expanded by Sabine Sampels (2015) [see Bibliography].

The most familiar amongst the technique applied in order to evaluate the shelf-life of any given seafood, provided it has been stored under melting ice: the Quality Index Method (QIM), with immediate evaluation of the results obtained, as exemplified by the gilthead seabream (Sparus aurata) scheme. Emphasis will be given to answering to the following questions:

• may any given species be endowed with more than one QI (= Quality Index) scheme?

• if so, which criteria will be implemented in order to pick and choose one of those schemes instead of any of all the others?

• how does a QI “reacts” to the adoption of, say, Modified Atmosphere Packaging (or MAP)

all the above questions being easily applicable to Sparus aurata?

Freezing as quite a popular storage method with seafood, special attention being paid to the sensory consequences of this practice, according to the fat content of the matrix. Frozen fish and Quality Index Method: the interesting case of cod (Gadus morhua).

Smoking: a curious technique which is both antique and yet quite modern as to the appeal it has to seafood consumers (suffice it to consider salmon and herring). The distinct sensory traits of both the cold smoked and the hot smoked seafood products will be outlined, having in mind Salmo salar as a useful example. An attempt will be made to follow the shelf-life evolution of hot and cold smoked farmed salmon.

Small pelagic fish fillets preserved in oil (from anchovy or Engraulis encrasicolus, to sprat or Sprattus sprattus - the Adriatic saraghina, and to sardine or Sardina pilchardus) as excellent examples of great sensory results, coupled with superior nutritional qualities and low prices. For these products, too, freshness quality of the raw material is of paramount importance. Therefore, for this material too, as observed for all the other matrices, shelf-life will be heavily affected by the origin lato sensu.

Marinading: much more a preparation than a conservation method, when it comes to finfish and shellfish, where it is liberally used. The very many approaches to seafood marinading, a real treat to gourmet consumers: do they have consequences, if any, as to the shelf-life of the prepared aliments?

Readings/Bibliography

AA.VV. Igiene e tecnologie degli alimenti di origine animale, G. Colavita (Ed.). Le Point Veterinaire Srl, Milano, 2012.

ASTM International. Standard Guide for Sensory Evaluation Methods to Determine the Sensory Shelf Life of Consumer Products, E2454 - 05 (reapproved 2011).

Bremner H.A. (Ed.). Safety and quality issues in fish processing. Woodhead Publishing Limited, Cambridge, England, 2002.

BSI Standards Publication. Sensory analysis - Assessment (determination and verification) of the shelf life of foodstuffs. BS ISO 16779:2015.

Man C.M.D., Jones A.A.. Shelf-life evaluation of foods, 2^nd ed. An Aspen Publication, Aspen Publishers, Inc., Gaithersburg, Maryland, USA, 2000.

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.

Moreover:

Sampels S. The effects of processing technologies and preparation on the final quality of fish products. Trends in Food Science & Technology, 44, 2015, 131–146.

Campus M., Bonaglini E., Cappuccinelli R., Porcu M.C., Tonelli R., Roggio T. Effect of modified atmosphere packaging on quality index method (QIM) scores of farmed gilthead seabream (Sparus aurata L. ) at low and abused temperatures. Journal of Food Science, 76 (3), 2011. S185–S191.

Teaching methods

At the very beginning of this course, lectures will have a “formal” look, slowly changing towards more interactive ways, in order to keep students' attention alive and awaken and to make the act of learning much easier and more natural.

Moreover, great emphasis will be given to the normosensitivity control of the students/panellists and to the supervised work students will be able to do, especially in order to outline the sensory profiles of couples of seafoods of widely different value, which is quite an unforgetable experience.

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

Students will have to take a 15-to-20-min. oral examination, during which they are expected to answer one question related to the sensory assessment of seafood shelf-life problems and how to prevent/solve them. This question will be drawn by each examinee out of a complete list, which will have been made timely available. This examination is completed by the other part (of the same "weight") by the title "Chemical and microbiological changes of seafoods during storage". The overall score will therefore be the aritmetic mean between the two individual scores.

Teaching tools

Videoprojector, PC, laboratories.

Office hours

See the website of Anna Badiani