Presentation on theme: "Classification of meat with boar taint using an electronic nose Agnes KIRSCHING, Gy. BAZAR, Z. HAZAS, R. ROMVARI."— Presentation transcript:
Classification of meat with boar taint using an electronic nose Agnes KIRSCHING, Gy. BAZAR, Z. HAZAS, R. ROMVARI
Boartaint Boar taint odor Meat from young boars (uncastrated male pigs) can present a distinctive unpleasant odor, known as boar taint, wich is detected during cooking and eating.
Boartaint Boar taint odor substances Patterson, 1968 Deposited in the fat Testicular steroid Urinary odour A part of the human population is insensible Treshold value 1.0 µg/g fat Vold, 1970; Walstra & Maarse, 1970 Walstra & Maarse, 1970 Deposited in the fat Product of the bacterial degra- dation of tryptophan in the gut Fecal odour Treshold value 0.21 µg/g fat Androstenone + Skatole
Detection methods of boar taint Chemical methods: Several methods: colorimetric, chromatographic, immunological Not applicable on the slaughter line Complicated sample preparation Labor and time demanding Human sensory method Human sensory method : Mainly used in slaughter houses the cooking/melting tests It is subjective At the present there is no on-line method for detecting and sorting out the boar tainted carcasses at the slaughter line. New possibilities the chemical gas sensor arrays, Electronic Noses (EN)
Aim of the study To test the applicability of electronic nose (EN) instrument for a discrimination of boar tainted samples of different meat parts.
Samples and preparation Pork chops from two entire male pigs with definite boar odor. Five different carcass parts: 1)loin 2)neck 3)shoulder 4)other thigh 5)inner thigh Meat samples of the two animals were cut into pieces and mixed heated for 1 hour at 75 ºC homogenized. Human sensory analysis EN measurement 0
Electronic nose (EN) measurement Sample preparation for EN 1 g homogenised pork meat + 1 ml of dilution into vials; closed with silica septa 20 parallels for each carcass parts (n=5×20) Headspace analysis An αFox 4000 (ALPHA MOS, Toulouse, France) type EN with 18 metal oxide sensors (MOS) in 3 chambers was used. Data evaluation AlphaSoft V.12 software SPSS 16 software package Sample temp. Equilibration time Injection volume Injection speed Flow rate 80 ºC180s with agitation 3000μl500μl/s150ml /min
Human sensory analysis procedure Selection of panelists, the training (n=17) Androstenone sensitivity of panelist was tested by triangle test (Lunde et al., 2009). Selection of panelists, the training (n=17) Androstenone sensitivity of panelist was tested by triangle test (Lunde et al., 2009). The sensory analysis procedure (n=11) The feshly cooked and homogenized meat samples were placed on the coded and covered plates. Panelists were required to rate the boar taint intensity of samples on 9 cm undivided line scale.
Results of human sensory analysis Result of androstenone sensitivity test: Among 17 panellists (12 women, 5 men) 4 (23.5%) were insensitive to androstenone. SamplesBoar taint Loin (1)1.81 Neck (2)3.25 Shoulder (3)2.43 Thigh outer (4)2.63 Thigh inner (5)2.37 The average boar taint score values by the human sensory panel (n=11)
Results of EN Results of EN measurement loin neck shoulder outer thigh inner thigh The first 2 function describing 97.2% of the total variance. Discrimination of the five meat samples using all EN sensors determined by the 1 st and 2 nd discriminant function Correctly classified samples: 94.8% Cross-validation: 83.3%
Results of EN Results of EN measurement 9 sensors (LY2/LG, LY2/G, LY2/AA, LY/gCT, P10/2, P40/1, T70/2, P30/1, P40/2) were chosen by the stepwise optimization method, and only these were involved in the DA. Discrimination of the meat samples using stepwise method Correctly classified samples: 91.7% Cross-validation: 86.5% Cross- validation LoinNeckShoulderOuter ThighInner ThighTotal Loin15020017 Neck020000 Shoulder00154019 Outer thigh00316120 Inner thigh10021720
Correlation between sensory panel and EN responses to boar taint Association between predicted (PLS) and reference (sensory panel) values of boar taint, based on EN data and human nose score obtained for the different meat parts R 2 =0.92 thigh outer thigh inner neck shoulder loin
Conclusions Based on the results of sensory panel it can be concluded that the intensity of boar taint perception increases with increasing level of fat content. The EN is able to discriminate with high accuracy different meat parts presenting different levels of boar taint. The EN responses were successfully calibrated against sensory panel scores.
Thank you for your attention! The financial support of TÁMOP-4.2.2/B-10/1 2010-0019 research grant is greatly acknowledged