At the forefront of fish texture testing

An independent study published in the Journal of Food Science has recognised the superior performance of Stable Micro Systems’ Warner-Bratzler shear blade in assessing firmness and texture in salmon fillets*.

The blade, which is used to assess the cutting force, or ‘bite’ of fresh fish, was the most sensitive method tested and yielded the most consistently accurate and repeatable data. As post-mortem quality degradation in fish continues to affect revenues, these conclusions will assist manufacturers looking to implement reliable, accurate and tested quality control procedures. 

The study aimed to establish the most suitable methods of detecting firmness in salmon fillets and predicting post-cold smoking texture. Researchers compared a new tensile strength test with various established analysis methods. All instrumental methods tested used Stable Micro Systems’ TA.XTplus texture analyser fitted with a 50kg load cell, controlled by Exponent software.

While the Warner-Bratzler shear blade was found to be the most effective method of measuring firmness and predicting post-smoking texture, the new tensile test provided the highest levels of accuracy when predicting post-mortem gaping (the appearance of tears or slits within the fillet on handling). The test, which used the TA.XTplus to pull samples apart while measuring the force required to do so, is a valuable addition to the existing pool of instrumental methods for fish flesh quality assessment.

Dr Ian Johnston, Fish Muscle Research Group, University of St Andrews, commented: “Approximately 40 percent of Atlantic salmon is downgraded during secondary processing due to soft flesh or gaping. Soft flesh results in a poor quality product with an unpleasant, mushy mouthfeel, while gaping causes unsightly fillets with low customer acceptability. Fillets with significant gaping are also unable to withstand the demands of mechanical handling and industrial processing. The results of our study will enable manufacturers to confidently undertake precise, consistent quality control.”

The Warner-Bratzler blade and TA.XTplus texture analyser are part of a wide family of texture analysis instruments and equipment from Stable Micro Systems. A portfolio of specialist products is available to measure and analyse textural properties of a huge range of food products, including bread volume, cheese extensibility, dough stickiness and yoghurt consistency.  

*A Novel Tensile Test Method to Assess Texture and Gaping in Salmon Fillets. Authors: T. J. Ashton, I. Michie and I. A. Johnston, Journal of Food Science (2010). 75: S182-S190.