92D-11 |
Predicting the remaining shelf life of vacuum-packed, sliced, smoked salmon: Sensory QIM testing compared with volatile base nitrogen components and their precursors as indices |
S. FU, Dept. of Food Science & Technology, Oregon State Univ., 100 Wiegand Hall, Corvallis, OR 97331-6602, W. F. A. Horner, Grimsby Institute of Food & Fisheries, Westside Rd., North Side Alexandra Dock, Grimsby, DN31 3 TD, United Kingdom, and R. F. Uglow, Dept. of Biological Sciences, Univ. of Hull, Aquatic Ecology & Resource Management, Hull, HU6 7RX, United Kingdom. The need to develop a rapid, simple and objective methods for assessing commercially-interesting parameters of quality is obvious. Because cold-smoked salmon is a valuable product, the development of an objective, industry-friendly methodology of predicting remaining shelf life is even more necessary and important. The objective of this study was to compare sensory scores, based on a “Quality Index Method” scheme developed specifically for the product, with H-factor (=([TMAO] + [TMA]) / [TVBN]) as indices of freshness/spoilage for predicting the Remaining Shelf Life of cold-smoked salmon stored at domestic refrigerator temperature. The extent to which nitrogenous bases have evolved in the flesh from their precursors was found to be a useful objective support to the usual sensory score-based prediction of shelf-life. The H-factor which, in exaggerated the small reduction in fish flesh TMAO (possibly due to enzymic conversion to DMA and formaldehyde) which occurred early in the shelf-life to show a more linear, storage time-dependent relationship than the individual TMA-N, TVB-N or TMAO-N concentrations and, therefore, greater potential as spoilage/freshness index for smoked salmon. The Flow Injection/Gas Diffusion apparatus, for determining the TMA, TVB and TMAO concentrations, proved to be a rapid technique with good reproducibility. It is suggested that it might be used alongside sensory testing to establish both storage time expired and RSL of unknown samples. validation of the sensory evaluation through chemical testing has been investigated here and the parameter, H-factor determined using the FIGD method appeared promising with respect to its steady change during chilled storage and the speed in which a result could be obtained. Further research is, nevertheless, needed to assess the applicability of H-factor as a freshness index to predict the RSL of both this product and those from other fish species.
Session 92D, Quality Assurance: General
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