| | This is the third in a series of reports on research completed as part of Animal Science 471-Applied Poultry Research at the University of Alberta during 2001.
Introduction
In a world where some believe that the human population is increasing faster than land can provide food, sustainable agriculture is becoming more important. To ensure future food availability, methods of utilizing agriculture waste products are needed. One by-product from the feed milling process is oat hulls. Oat hulls can be recycled as a feed source for house fly larvae. These larvae can then be fed to poultry as a protein source. It is important to determine if this kind of alternative protein source causes a change in meat flavour. Flavour is the most important characteristic of consumer acceptance. The effect of a drastic change to a diet on the flavour of the meat should be measured using a sensory panel.
What is sensory analysis and why is it important?
Sensory analysis is the process of determining consumer acceptance of a new or improved product. Consumer acceptance is a reality check for developing products. If the consumers hate a product, there is no need to develop that product further. Without consumer acceptance, even a perfect, environmentally sound product won't "fly". Sensory analysis takes the form of a consumer sensory panel, which is essentially a blind taste test. A recent study at the University of Alberta tested the consumer acceptance of turkeys fed a diet containing 7% larvae for 37 days. We were interested to see if the addition of larvae to a turkey diet would produce an acceptable quality of meat relative to those fed a diet without larvae.
How was it done?
In this trial forty Hybrid turkeys were divided into 2 groups, a "control" group that received no larvae and the "larvae" group that received larvae as a protein supplement. A sensory panel evaluated the meat for seven different sensory characteristics. The sensory characteristics were appearance, colour, tenderness, juiciness, flavour, overall opinion and likelihood of purchase. To evaluate the sensory characteristics a 9-point hedonic scale was used. The hedonic scale runs from 1 (dislike extremely) to 9 (like extremely). The sensory panel consisted of 99 people from the University of Alberta (45 participants were male and 54 were female). Out of these 99 panelists, 22 panelists consumed turkey once or twice a week, 4 consumed turkey products three or four times a week and 1 panelist consumed turkey products 5 times a week or more. The panelists indicated that when given the choice, 26 frequently bought products that utilize recycling methods or environmentally aware processes, 71 sometimes bought these products and 2 never bought these products.
Sensory panel
The panelists were given three samples of meat; a control fed, larvae fed and a warm up sample. The warm up sample was a piece of turkey purchased from a local market, which was used to give the panelist a reference before tasting the other samples to eliminate any biases. Through the panel we learned that the control sample had a superior flavour, which led to a greater overall opinion and a stronger likelihood of consumer purchase when compared to the other samples. The consumers on the panel found that the sample of meat from the larvae fed had a flavour that was distinct from the control group. The panelists concluded that the control sample was better than the larvae sample. The warm-up sample was comparable to the larvae sample because there were no significant differences between the ratings of any of the sensory characteristics. These conclusions may be misleading because they imply that the larvae sample was equivalent to the warm-up sample. This is not an accurate conclusion because we had no control over that turkey's growing conditions, age and sex. These unknown factors do not supply accurate results, and are the reason why we cannot accurately compare these two samples.
Future development
The oat hull recycling process shows great promise. However, the process is currently very labour intensive and expensive. High costs do not make fly larvae as a feed additive competitive with a standard commercial diet. Further innovation in larvae production may decrease the cost and lead to more comparable feed prices. With lower prices, producers would be able to afford this feed supplement and offer the consumers product choice. It should be noted that this trial indicated consumers generally showed less preference for the flavour of larvae fed turkeys; therefore it may not be feasible for producers to market this product to a wide commercial audience. However, the product may be very appealing to a small niche market that seeks organically and sustainably grown products.
Summary
As a sustainable agriculture practice the oat hull recycling process is beneficial. However, the change in flavour and decreased consumer acceptance of the finished product may obstruct this application of the recycling process. Further research in using larvae as a feed supplement for market age turkey is required.
Editors note
If there was no difference between the retail sample and the larvae-fed sample, the difference is probably not enough to be noticed by the average consumer, and should not affect sensory acceptability of the product.
F. C. Clarke, A. A. Ryder, and A. C. Sayers
Poultry Research Centre News Vol 10 No 3, November 2001 |
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