The accelerated freeze-drying (AFD) method of food preservation / a report on some work of the Research Establishment and Experimental Factory of the Ministry of Agriculture, Fisheries and Food, Aberdeen, Scotland, between 1955 and 1960.

  • Great Britain. Ministry of Agriculture, Fisheries and Food.
Date:
1961
Catalogue details

Licence: Public Domain Mark

Credit: The accelerated freeze-drying (AFD) method of food preservation / a report on some work of the Research Establishment and Experimental Factory of the Ministry of Agriculture, Fisheries and Food, Aberdeen, Scotland, between 1955 and 1960. Source: Wellcome Collection.

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    of dishes with no frills or trimmings, but of course this would have been equally true of fresh material prepared under similar conditions. TASTE PANELS The eating quality of a product is the final criterion by which it is judged, and in the quality control department of a food factory or research organiza- tion this judgment is normally carried out by presenting the food, prepared by the simplest practical method, to a number of people to taste, and for them to assess its quality in terms of appearance, flavour and texture. There are many ways of conducting such ‘taste panels’ and of choosing the members. For certain purposes a so-called ‘analytical panel’ is valuable and this is the type which was normally used at Aberdeen. A ‘consumer panel’, which should indicate the acceptability of a product to the public, obviously cannot be reliably conducted with only a small number of tasters; but an analysis of qualities can be undertaken by a few trained persons, who are able to assess small differences in colour, flavour and texture, resulting perhaps from differences in production techniques and storage conditions. Choosing a panel Because of the large range of foodstuffs investigated at Aberdeen a single panel for all commodities was out of the question. One person could not be expected to possess sensitivity to all the flavours under test. Instead, four panels were formed, each corresponding to one of the major divisions in food, i.e., Meat, Fish, Vegetables and Fruit. All members of staff available for tasting were tested to discover if they could detect small variations in flavour in all four sections. Material was specially prepared so that differences were judged to be detectable but not too obvious. (This could be verified by the results. If over 75 per cent were correct they were too obvious and if under 334 per cent were correct, the differences were not great enough for the purpose.) The samples were presented, under code, in triangular tests, 1.e., two samples of one and one sample of the other. Panel members were asked to pick out the odd one and state their reason. Each test was duplicated and the results analysed by a statistician. Those people with no flavour sensitivity were discarded. Four provisional panels were now composed of those people whose palates were found to be most sensitive to small flavour changes in either meat, fish, vegetables or fruit. The people who gave correct results for more than one commodity were at this stage included in each panel. These provisional panels were further tested in their own section only, by triangular tests in which the flavour difference was barely detectable. The results were again statistically analysed and the 9-10 members giving the best results were nominated to that specific panel. A period of training now followed when the members were familiarized with the score sheets and introduced to the various known off-flavours which occurred in their particular commodities, and the terms used to describe them. By presenting this panel with identical groups of samples at intervals of time their reliability was further judged and the final selection of 7-8 members made. A panel of six was considered the smallest number of significance and the additional mem- bers were included to allow for absentees. Score sheets: The commonly used difference-test and a numerical scoring method based on a graduation from ‘very good’ to ‘very bad’ did not give