Potential application of electonic nose in processed animal proteins (PAP) detection in feedstuffs

Electronic nose and olfactometry techniques represent a modern analytical approach in food industry since they could potentially improve quality and safety of food processing. The aim of this study was to evaluate possible application of electronic nose in PA P detection and recognition in feed. For this purpose 6 reference feedstuffs (CRA-W / UE STRAT FEED Project) were used. The basis of the test samples was a compound feed for bovine fortified with processed animal proteins (PAP) consisting of meat and bone meal (MBM) and/or fish meal at different concentrations. Each feed sample was tested in glass vials and the odour profile was determined by the ten MOS (metal oxide semi-conductor) sensors of the electronic nose. Ten different descriptors, representing each ten sensors of electronic nose, were used to characterise the odour of each sample. In the present study, electronic nose was able to discriminate the blank sample from all other samples containing PA P (M B M, fish meal or both). Samples containing either 0.5% of MBM or 5% of fish meal were identified, while samples containing a high fish meal content (5%) associated with a low MBM content (0.5%) were not discriminated from samples containing solely fish meal at that same high level (5%). This latter indicates that probably the high fish meal level, in samples containing both MBM and fish meal, tended to mask MBM odour. It was also evident that two odour descriptors were enough to explain 72.12% of total variability in odour pattern. In view of these results, it could be suggested that electronic nose and olfactometry techniques can provide an interesting approach for screening raw materials in feed industry, even though further studies using a wider set of samples are needed