Presentation on theme: "Classification of meat with boar taint using an electronic nose"— Presentation transcript:
1 Classification of meat with boar taint using an electronic nose Agnes KIRSCHING,Gy. BAZAR, Z. HAZAS, R. ROMVARI
2 Boar taint odorMeat from young boars (uncastrated male pigs) can present a distinctive unpleasant odor, known as boar taint, wich is detected during cooking and eating.
3 Boar taint odor substances Androstenone SkatoleVold, 1970;Walstra & Maarse, 1970Deposited in the fatProduct of the bacterial degra-dation of tryptophan in the gutFecal odourTreshold value 0.21 µg/g fatPatterson, 1968Deposited in the fatTesticular steroidUrinary odourA part of the human population is insensibleTreshold value 1.0 µg/g fat
4 Detection methods of boar taint Chemical methods:Several methods: colorimetric, chromatographic, immunologicalNot applicable on the slaughter lineComplicated sample preparationLabor and time demandingHuman sensory method:Mainly used in slaughter houses thecooking/melting testsIt is subjectiveAt 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)
5 Aim of the studyTo test the applicability of electronic nose (EN) instrument for a discrimination of boar tainted samples of different meat parts.
6 Samples and preparation Pork chops from two entire male pigs with definite boar odor.Five different carcass parts:loinneckshoulderother thighinner thighMeat samples of the two animals werecut into pieces and mixedheated for 1 hour at 75 ºChomogenized. Human sensory analysisEN measurement
7 Electronic nose (EN) measurement Sample preparation for EN1 g homogenised pork meat + 1 ml of dilution into vials; closed with silica septa20 parallels for each carcass parts (n=5×20)Headspace analysisAn αFox 4000 (ALPHA MOS,Toulouse, France) type EN with18 metal oxide sensors (MOS)in 3 chambers was used.Sample temp.Equilibration timeInjection volumeInjection speedFlow rate80 ºC180s with agitation3000μl500μl/s150ml/minData evaluationAlphaSoft V.12 softwareSPSS 16 software package
8 Human sensory analysis procedure 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.Selection of panelists,the training (n=17)Androstenone sensitivityof panelist was testedby triangle test(Lunde et al. , 2009).
9 Results of human sensory analysis Result of androstenone sensitivity test:Among 17 panellists (12 women, 5 men) 4 (23.5%) were insensitive to androstenone.The average boar taint score values by the human sensory panel (n=11) SamplesBoar taintLoin (1)1.81Neck (2)3.25Shoulder (3)2.43Thigh outer (4)2.63Thigh inner (5)2.37
10 Results of EN measurement Discrimination of the five meat samples using all EN sensors determined by the 1st and 2nd discriminant functionloinneckshoulderouter thighinner thighThe first 2 function describing 97.2% of the total variance.Correctly classified samples: 94.8%Cross-validation: 83.3%
11 Results of EN measurement Discrimination of the meat samples using stepwise method9 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.Correctly classified samples: 91.7%Cross-validation: 86.5%Cross-validationLoinNeckShoulderOuter ThighInner ThighTotal1521720419Outer thigh3161Inner thigh
12 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 partsR2=0.92thigh innerneckthigh outerloinshoulder
13 ConclusionsBased 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.
14 Thank you for your attention! The financial support of TÁMOP-4.2.2/B-10/ research grant is greatly acknowledgedThank you for your attention!