2005 IRISH SCIENTIST YEAR BOOK

Home Page

Table of contents

Index by Author

Index by topics

Search


Teagasc � The National Food Centre, Ashtown, Dublin 15
Ronan Gormley
Fish as a functional food

Composite of tuna cubes, cylindrical tumbler, and HPLC system for taurine estimation

A number of authors have shown that taurine (NH 2 CH 2 CH 2 SO 3 H) is beneficial for the cardiovascular system. Specifically, Fennessy et al. [Circulation, 107(3): 410-415, (2003)] have shown that taurine (circa 1g/person/day) modified endothelial dysfunction in young smokers, i.e. it restored elasticity to the brachial artery and presumably to other arteries also. These findings prompted the current study at The National Food Centre on the taurine content of raw flesh of different fish species (Trial 1). In Trial 2 tumbling was used to introduce additional taurine into tuna fish cubes thereby making them (potentially) a functional food. Tumbling is used in the meat/muscle foods industry and involves treating meat pieces in a solution (e.g. of brine or pickle) in a slowly rotating stainless steel cylinder under vacuum resulting in the uptake of some of the solution by the meat. These trials were conducted as part of the EU SeafoodPlus Integrated Project (website: www.seafoodplus.org ).

Raw portions of plaice, cod, mackerel and farmed salmon were purchased in supermarkets (Trial 1) on four occasions (bi-weekly) and the taurine content was measured by HPLC. In Trial 2, tumbling in a solution of taurine (7.5%w/v) (with polyphosphate) was used to introduce additional taurine into yellowfin tuna cubes. The fish samples were then subjected to four post-tumbling processing treatments, i.e. freezing (-20�C/5d); chilling (4�C/6d); freeze-chilling (-20�C/5d and 4�C/6d); sous vide cooking (90�C/10 min)] and the level of taurine retention was measured in cooked (microwaved) and uncooked samples.

Taurine contents (Trial 1) were in the order plaice [range 100-160mg/100g wet weight (ww)] > cod (60-100) > mackerel (60-80) > farmed salmon (40-60). In Trial 2 taurine contents of circa 800-1000mg/100g ww (target 1%) were achieved in the tumbled tuna portions and these levels were largely retained in the frozen, chilled, freeze-chilled, sous vide cooked and microwaved samples. These data show that fish are a significant source of taurine in the diet and stress again the importance of regular fish consumption.

Contact: Dr T. Ronan Gormley, Teagasc,
The National Food Centre, Ashtown, Dublin 15;
E-mail: [email protected] ;
Web: http://www.teagasc.ie/nfc/