“Chilled” pork—Part I: Sensory and physico-chemical quality

Meat Science 92 (2012) 330–337

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“Chilled” pork—Part I: Sensory and physico-chemical quality T.M. Ngapo a,⁎, L. Riendeau b, C. Laberge c, D. Leblanc a, J. Fortin a a b c

Food Research and Development Centre, Agriculture and Agri-Food Canada, 3600 boul. Casavant Ouest, St-Hyacinthe, Québec, Canada, J2S 8E3 Centre de Développement du Porc du Québec Inc., Place de la Cité - Tour Belle Cour, bureau 450, 2590 boul. Laurier, Québec City, Québec, Canada, G1V 4M6 Statex, 3332 de la Paix, Sainte-Foy, Québec, Canada, G1X 3W6

a r t i c l e

i n f o

Article history: Received 23 January 2012 Received in revised form 23 April 2012 Accepted 25 April 2012 Keywords: Chilled Sensory quality Pork Export Ageing

a b s t r a c t Chilled meat exportation comprises chilling within 48 h post-mortem to temperatures b 0 °C without freezing and holding under these conditions for several weeks. The effects of this ageing on sensory quality of pork are unknown and hence the objective of this study was to compare the sensory quality of Canadian pork as found in an export (Japan) market and locally. Regardless that the Japanese market's quality criteria were met, pork sorted on-line differed (Pb 0.05) from that for the domestic market only for lightness, exudate and cooking loss; no differences in intramuscular fat content were observed. Overall, a trained panel scored weaker pork and meat flavours and odours in the export than the domestic pork as a result of either the quality by selection if roasted or the ageing (−1.7 °C, 43 days exported chilled or 3.1 °C, 5 days domestic) if grilled or shabu shabu. Grilled pork was also more tender, sweeter and had stronger caramel flavour with the chilled ageing. Crown Copyright © 2012 Published by Elsevier Ltd. All rights reserved.

1. Introduction Canadian “chilled” pork, like any chilled export meat, is subject to what might be considered unusual ageing. Chilled meat exportation comprises chilling meat within 48 h post-mortem (p.m.) to strictly controlled temperatures below 0 °C without freezing and holding under these conditions for several weeks. This type of exportation achieves a meat that competes with that in the fresh meat market at the end of transportation and is generally found in higher value markets, for example, New Zealand lamb in European and North American markets, or beef and pork from these latter markets in Japan. Fresh and “chilled” meats often compete alongside each other in the marketplace, and it is therefore surprising to find very little scientific literature describing sensory quality after chilled transportation compared to fresh, particularly in pork. Three weeks storage of pork at −1.5 °C under 100% CO2 was studied by McMullen and Stiles (1994). After the chilled storage, the samples remained acceptable for retail sale for two weeks at 4 °C or one week at 7 °C, appearance being the principal criterion limiting storage life. Discolouration was not a problem, but purge and odour became so with time. Jeremiah, Gibson, and Argnosa (1995) found that off-flavour development restricted the storage life of pork loin stored at −1.5 °C for 9 weeks in both CO2 controlled atmosphere and vacuum packaging. In both of these papers, as in much of the “chilled” meat literature, microbiological quality was the focus of the work and sensory evaluation was applied generally to detect unpleasant or off-flavours and the limits of shelf-life. Aside from detection

⁎ Corresponding author. Tel.: + 1 450 768 3300; fax: + 1 450 773 8461. E-mail address: [email protected] (T.M. Ngapo).

of negative characteristics and prior to the shelf-life limit, there appear to be no reports on the sensory profile of pork after the long period under chilled conditions when exported to distant markets, such as from Canada to Japan. Does ageing take place and to what effect? In Canada, as in other countries exporting to Japan, in order to meet the importers requirements pork is either produced specifically for this market or selected on-line. The Japanese market is very discerning and importers demand selection criteria which are readily measured by the exporter often without consideration of the relevance of these criteria to the domestic market. These criteria typically include marbling scores of 2–4 on the NPPC scale (NPPC, 1999), colour scores of 3–4 on the Japanese Pork Colour Standards (Nakai, Saito, Ikeda, Ando, & Komatsu, 1975) and firmness so that the loin is firm to the touch at the ends of the loin. The search for on-line measures of meat quality is well documented and has been an industry priority for many years. A good deal of literature reports on the influence of marbling and/or intramuscular fat content on the sensory quality of pork and it is generally accepted that meat lipids provide flavour and aroma volatiles that impact on flavour. However, in spite of more than 25 studies on the subject, the role of IMF (for which marbling is a visual estimation) in the sensory quality of pork is not understood. Studies show positive, negative or no influence on the sensory attributes of pork and this disparity is a continuing source of investigation (Ngapo & Gariépy, 2008). Despite the disparity, workers continue to propose minimum IMF contents varying from 1% (Wood, 1990) to 4% (Gandemer et al., 1990) with the aim of ensuring satisfactory eating characteristics of pork. And like Japanese importers, a range, albeit more limited, from 2.5–3.0% IMF has been proposed by De Vol et al. (1988). Other than studies on PSE and DFD meat, colour is generally not directly related to pork quality. In an extensive study on correlations

0309-1740/$ – see front matter. Crown Copyright © 2012 Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.meatsci.2012.04.032

T.M. Ngapo et al. / Meat Science 92 (2012) 330–337

of meat quality characteristics, Huff-Lonergan et al. (2002) found that subjective colour was significantly correlated with most sensory traits except juiciness. However, although the correlation between subjective colour and flavour was significant, the magnitude of the correlation was small enough to indicate that other factors may have a greater influence on flavour. As for colour, these workers also found that the other criteria imposed by Japanese importers, marbling and firmness scores, were significantly correlated with most sensory traits except juiciness. Verification of the pertinence to sensory quality of the selection criteria used for pork exports to Japan therefore has the potential to provide organoleptic quality predictors for on-line use locally. The objective of this study was to compare the sensory quality of Canadian pork destined for Japanese and domestic markets, with particular reference to the export selection criteria imposed by Japanese importers and the transportation conditions. 2. Materials and methods 2.1. Chemicals, reagents and water All chemicals and reagents used were at least analytical grade. Water was deionised.

331

(shabu shabu), 8 cm for shear force, 18 cm for sensory evaluation (grilling), 2 cm for sarcomere length and any remaining meat was discarded. Starting at the posterior end of the right loin, portions were taken in the following order: 18 cm for sensory evaluation (roasting), 2 cm for colour, pH and sex, 2 cm for fat oxidation, 2 cm surplus, 18 cm for consumer evaluation (Ngapo, Riendeau, Laberge, Houde, & Fortin, submitted for publication), 2 cm for proximate analyses and any remaining meat was discarded. The m. longissimus dorsi was isolated from surrounding muscles for all evaluations and measurements. 2.4. Exudate, colour and pH Exudate, colour and pH were measured during portioning. The exudate was measured by difference of the total weight of the packaged loin and the weight of the loin immediately upon removal from the packaging. Exudate was expressed as a percent of the sum of the loin and exudate. A 2 cm slice of loin was bloomed, 45 min at room temperature and CIE L*a*b* colour parameters measured on the M. longssimus thoracis et lumborum using a Hunterlab Labscan Spectrophotometer (6 cm aperture; V1-A30, Hunter Associate Lab, Inc., Reston, VA, USA) calibrated with black and white tiles (illuminant D65, CIE 10° observer). The pH was the mean of readings taken using a glass probe with temperature compensation at three sites on the slice of loin.

2.2. Pork and collection 2.5. Sex determination Pork loins were obtained from a commercial slaughter-line. The animals had been slaughtered at about 110 kg live weight and the dressed carcasses hung at 2 °C. At 24 h p.m., both loins (boneless, short cut) from 40 pigs were collected on-line. Abattoir staff sorted the loins achieving 20 pairs each of export and domestic quality. In this abattoir, selection of export quality pork for the Japanese market is achieved subjectively by marbling score (2–4 on the NPPC scale; NPPC, 1999) and colour (3–4 using the Japanese Pork Colour Standards; Nakai et al., 1975) estimated along the centre of the loin surface, and firmness (firm to the touch at the ends of the loin). Loins that do not meet these criteria are retained for the domestic market. After sorting, all loins were individually vacuum packaged, placed in boxes of four, cardboard dividers separating the loins, and stored at 0.5 °C. At 48 h p.m. the loins were transported under refrigeration to the laboratory. 2.3. Ageing/chilling and portioning Ten each of the vacuum packaged and boxed domestic and export loin pairs were held in a walk-in refrigerator at 3.1 °C (±0.4 °C) measured using four HOBO RH/temp dataloggers (H08-003-02, Onset Computer Corporation, Bourne, MA, USA). At 7 days p.m. these loins were portioned. The remaining 20 loins (10 each of domestic and export quality) were held at a mean core meat temperature of −1.7 °C (±0.1 °C) measured by two Class ‘A’ platinum resistance temperature detectors (PT100 RTDs) with hermetically sealed sensor tips connected to OM-CP-QUADRTD 4-channel temperature dataloggers (Omega Engineering, Inc., Stamford, CT, USA). Measurement of core temperature was made on loins used only for this purpose. The circulating air temperature and that inside the boxes holding the loins were also measured using six PT100 RTDs mounted in open-end stainless steel housing (−0.42 °C±0.27 °C and −0.70 °C±0.32 °C, respectively). Daily thawing cycles of the refrigeration system were undertaken. All RTDs had PFA insulated leads. Readings were taken every 5 min during the 43 day period, after which the loins were portioned. Pre-trials were undertaken to verify that crystals did not form in the meat at the given temperatures over the 43 day period. At the completion of the ageing periods (that is, at 7 or 45 days p.m.), the loins were portioned at 5 °C for chemical, sensory and consumer tests and the portions individually vacuum-packaged and stored at −40 °C until required. Starting at the posterior end of the left loin, portions were taken in the following order: 18 cm for sensory evaluation

Extraction of DNA from pork loins was undertaken using an Agencourt® RNAdvance Tissue kit (Beckman Coulter, MA, USA) according to the manufacturer's recommendations for fibrous tissue by plate format. Optional DNase treatment was omitted. Homogenization of the sample (10 mg) was achieved using metal beads (5 mm) for 25 min with a Tissue Lyser (Qiagen, ON, Canada). Plates were incubated at 37 °C for 45 min. The DNA was extracted from homogenised lysates (400 μl) and eluted in RNAse free water (50 μl; Gibco, ON, Canada). No-sample extraction and positive extraction controls (female and male animals) were also included. The PCR amplifications were carried out in Eppendorf Mastercycler® Gradient thermocycler. A HotStarTaq® Plus PCR kit was used according to the specifications. The reaction mixture contained the sex determination primers SRYB-5 and SRYB-3 (80 nM each; Pomp, Good, Geisert, Corbin, & Conley, 1995) and PCR validation primers P1-5EZ and P2-3EZ (160 nM each; Aasen & Medrano, 1990) in 20 μl final volume. An initial incubation step of 5 min at 95 °C was followed by 35 cycles of incubation at 94 °C for 1 min, 55 °C for 45 s and 72 °C for 1 min. Fragments of 163 bp generated by the SRYB PCR products are present only in male samples. Fragments of 445 bp or 447 bp from female or male genomic DNA, respectively, corresponding to ZFX or ZFY genes, respectively, were produced and served as amplification controls. 2.6. Proximate analyses Moisture, protein and intramuscular fat (IMF) contents were measured using AOAC official methods of analysis 985.14, 992.15 and 991.36, respectively (AOAC International, 2005). The vacuum-packaged loin slice was partially thawed in a circulating waterbath at 25 °C for 30 min and then removed from the packaging. The m. longissimus dorsi was isolated and minced in a GE Deluxe Chopper 169121R (Bentonville, AR, USA) at low speed (2 ×15 s) to give a homogenous sample. Moisture content analyses were made and the remaining minced meat vacuum packaged, frozen and stored at −40 °C. When required for analyses of protein and IMF contents, the frozen minced meat was completely thawed at room temperature and well mixed. Moisture content analyses were undertaken in duplicate by rapid microwave drying using a CEM SMART System5 (CEM Corporation, Matthews, NC, USA). A thin layer of accurately weighed pork (3 g) was spread onto the rough side of a glass fibre pad and covered with a second

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pad, dried to a constant weight at 85% power. The moisture content was calculated by difference and expressed as the weight percent of the wet weight of the pork sample. Protein content was measured in triplicate (0.2 g pork per replicate) by combustion using a Leco FP428 Nitrogen and Protein Determinator (Leco Corporation, St. Joseph, MI, USA). At least ten blanks (empty tin capsules) and six EDTA standards (0.2 g each) were used on each sampling day. Protein content was calculated using a conversion factor of 6.25 and expressed as the weight percent of the wet weight of the pork sample. Crude IMF content was measured in triplicate by ether extraction using a Solvent Extractor (Velp Scientifica SER 148/6, Europe). Pork (3 g) was accurately weighed into a thimble containing sand (about 20 g) and mixed with a glass rod. The thimble was dried 1 h at 125 °C in a convection oven then removed to room temperature to cool. The sample/sand mixture was loosened using a glass rod which was wiped clean with a small amount of cotton wool, and the cotton wool placed in the top of the thimble. The thimble was transferred to the extraction unit and the sample extracted with petroleum ether (40 ml) by submersion for 25 min and rinsing for 30 min at a condensation rate of ≥5 drops/s. The extraction cup and contents were dried 30 min at 125 °C, then cooled to room temperature and weighed. The IMF content was calculated by difference and reported as the weight percent of the wet weight of the sample. 2.7. Fat oxidation The extent of IMF oxidation was evaluated by measuring thiobarbituric acid reactive substances (TBARS) as described by Witte, Krause, and Bailey (1970) with modification. The vacuum packaged loin slice was partially thawed by standing 1 h in cold tap water then removed from the packaging. Two samples (10 g each) were cut from the m. longissimus dorsi and each blended in a Waring Commercial Blender 7011HS (full speed, 45 s; Waring, Torrington, CT, USA) in a chilled stainless steel 110 ml capacity cup with chilled 20% trichloroacetic acid (TCA; 25 ml, 4 °C). The resulting slurry was transferred quantitatively to a polypropylene tube, made up to 50 ml with water, mixed by shaking and filtered (Whatman No. 2 filter paper). Aliquots (2 ml) of the filtrate were transferred to test tubes and 0.005 M 2-thibarbituric acid (TBA; 2 ml) added. The tubes were stoppered, mixed by inversion and held 17–18 h in the dark at room temperature. The resulting colour was measured at 530 nm (Cary 50 Bio UV–vis spectrophotometer, Varian Australia Pty Ltd, Melbourne, Vic, Australia) and expressed in mg malonadehyde/kg pork from the average of duplicates of filtrate. Absorbance values from the reaction of 0.005 M TBA (2 ml) solution with serial dilutions (10 − 8–10− 7 M) of 1,1,3,3-tetraethoxypropane (TEP) were used to generate a standard curve. The TEP (240 μl) was initially diluted to 10 ml with ethanol; all subsequent dilutions were made with 20% TCA. The rate of recovery was determined by comparison of samples with and without 1 × 10 − 4 M TEP (50 μl) added at blending. An average of 87% (s.d. 11%) recovery was observed from 14 different pork samples. 2.8. Shear force and cooking loss Shear force and cooking loss were measured using the methods of Honikel (1998) with modification. Vacuum packaged loin portions were partially thawed in a circulating water-bath at 25 °C for 45 min then removed from the packaging. Two blocks (7× 6 × 4 cm3) were cut from the m. longissimus dorsi with the longest axis parallel to the fibre direction. For each run of three animals (six blocks of pork), CNS needle thermocouples (type T, 5.9 cm, 1.45 mm diam, C-5.1 ML receptacles; Ecklund-Harrison Technologies, Inc., Fort Myers, FL, USA) were inserted into the centre of two additional blocks of pork loin (nonexperimental) used to follow the temperature during cooking. The

samples and temperature controls were vacuum packaged and randomly placed in a multi-process retort (Retort FL-14 Stock Pilot Rotor 900, Hermann Stock Maschinenfabrik GmbH, Neumünster, Germany). Temperature acquisition was achieved using a 2620A Hydra Series II data acquisition unit (John Fluke Manufacturing Company, Inc., Everett, USA) and viewed with Labtech Notebook Pro XE (Version 12.1; Andover, MA, USA). The blocks were cooked by water spray circulation with step increases in temperature of 10 °C/5 min from an internal temperatures of about 0 °C to 71–72 °C, prior to cooling to 30 °C with chilled water. The vacuum seal was punctured and the blocks were removed to a refrigerator (5 °C) for 20 h. The blocks were then removed from the bags, blotted dry and weighed. Cooking loss was calculated by difference and expressed as a percentage of the initial block weight. Cooking loss was measured in duplicate. Lengths of pork (1× 1 × 3 cm3) were cut from each block parallel to the fibre direction. The lengths were sheared at a right angle to the fibre direction with a Warner Bratzler shear blade (1.0 mm straight edged blade, v-shaped, 60° angle, 100 mm/min shear rate, 1.5 mm blade slot) attached to a Texture Analyser TA-XT2 (Stable Micro Systems, Surrey, UK). The peak force (in kg) was recorded as the average of the force deformation curves of 10 lengths of pork. 2.9. Sarcomere length Sarcomere length measurement was undertaken using the method of Cross, West, and Dutson (1980–1981). Vacuum packaged loin slices were partially thawed in cold tap water, removed from the packaging and samples (2.5 g) cut from the m. longissimus dorsi. The samples were homogenised (Polytron PT-MR 3100 with a PT 3012/2 T dispersing aggregate; Kinematica AG, Littau, Switzerland) for 15–25 s at 16,500 rpm in a 0.2 M sucrose solution (25 ml). A drop of the homogenate was transferred to a slide and covered with a cover slip. The slide was examined by phase microscopy (400×), and images were captured with Spot Imaging Software Advanced (Version 4.0.9, 1997–2004, Diagnostic Instruments, Inc., Sterling Heights, MI, USA) and analysed with Image-Pro Plus (Version 4.5.0.19, 1993–2001, Media Cybernetics, Inc., Bethesda, MD, USA) calibrated with a stage micrometer. The mean sarcomere length of each muscle was the average of measurements of lengths of 10 sarcomeres on each of 25 myofibrils. 2.10. Sensory evaluation 2.10.1. Grilling The 18 cm loin segment was sliced (2 cm) frozen using a band saw, and the slices of a given segment vacuum packaged together and returned to the freezer at −40 °C until required. At 43 h prior to grilling, the slices were partially thawed at 4 °C for 18 h followed by 2 h at room temperature ensuring that the core temperature of the block of slices did not rise above −2 °C (Digisense penetration thermocouple probe with hypodermic tip, type T, 10 cm, Cole Parmer, Missisauga, ON, Canada, read with an HH21 Microprocessor Thermometer, Omega Engineering, Inc., Stamford, USA). The m. longissimus dorsi was isolated retaining a fat cover of about 5 mm. The semi-frozen slices were placed in aluminium trays, covered with aluminium foil and held at 4 °C for 23 h. If the core temperature of the pork slice was ≤−1 °C at 1 h prior to grilling, the slice was removed to room temperature to bring all slices to 0–4 °C for grilling. The slices were cooked on a double-sided grill (Eurodib double panini grill PDR E, Sirman S.p.a., Padova, Italy) at 160 °C, two slices per grill section, to a final core temperature of 72 °C (type T precision fine-gage thermocouples with PFA insulation read with HH21 Microprocessor Thermometer, Omega Engineering, Inc., Stamford, CT, USA) as measured in one of each pair of slices. The slices were halved, and each half placed in a pre-heated glass Petri dish (60 °C), covered and held at 60 °C until evaluation (no longer than 30 min). The grill was brushed with a wire brush between samples.

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2.10.2. Roasting At 48 h prior to roasting, the 18 cm loin segment was partially thawed at 4 °C for 20 h and at room temperature for 2 h ensuring that the core temperature did not rise above −2 °C (Digisense penetration thermocouple probe with hypodermic tip, type T, 10 cm, Cole Parmer, Missisauga, Canada, read with an HH21 Microprocessor Thermometer, Omega Engineering, Inc., Stamford, CT, USA). The m. longissimus dorsi was isolated retaining a fat cover of about 5 mm. The semi-frozen loin roasts were placed in aluminium trays, covered with aluminium foil and held at 4 °C for 24 h. If the core loin roast temperature was ≤−1 °C at 1 h prior to cooking, the loin roast was removed to room temperature to bring all roasts to 0–4 °C for cooking. Each loin roast was placed in a polyester oven bag (Look oven bags, Terinex, Bedford, UK) in a roasting dish, closed with a tie and six 1 cm slits made in the top of the bag. A thermocouple (type T precision fine-gage thermocouples with PFA insulation read with HH21 Microprocessor Thermometer, Omega Engineering, Inc., Stamford, CT, USA) was inserted into each roast. The roasts were cooked in a convection oven at 177 °C (aerobake setting, Fisher and Paykel Aerotech oven S302, Fisher and Paykel, Huntington Beach, CA, USA), to an end-point core temperature of 72 °C. The extremes of the roasts (4 cm) were discarded, and the remainder sliced (1.5 cm). The slices were halved and each placed in a pre-heated glass Petri dish (60 °C), covered and held at 60 °C until evaluation (no longer than 30 min). 2.10.3. Shabu shabu At 46 h prior to slicing, the loin segment was partially thawed at 5 °C for 24 h ensuring that the core temperature of the block of slices did not rise above −2 °C (Digisense penetration thermocouple probe with hypodermic tip, type T, 10 cm, Cole Parmer, Missisauga, ON, Canada, read with an HH21 Microprocessor Thermometer, Omega Engineering, Inc., Stamford, CT, USA). The m. longissimus dorsi was isolated at 4 °C retaining a fat cover of about 5 mm and the meat sliced using a Hobart 1612 commercial meat slicer (Hobart Canada Inc., Don Mills, ON, Canada) to 1.3–1.5 mm thickness. The slices were placed separately between layers of parchment paper, vacuum packaged and held at −20 °C for 22 h. At 35 min prior to cooking, the slices were held on ice prior to cooking one at a time. Each slice was peeled from the paper with silicon tongs, swayed back and forth three times (about 3 s total) in boiling water (500 ml), removed to preheated amber glass jars (60 °C), capped and held at 60 °C until evaluation (no longer than 30 min). Four slices of a sample were placed in each jar. The boiling water used to cook the pork was changed between every four slices of a given sample.

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Table 1 Descriptive terms and definitions for the trained panel evaluation of pork. Attribute

Definition

Odour (score out of 8) Meat Pork

Odour associated with Meat complex/lean/brothy Cooked pork lean

Flavour (score out of 8) Meat Pork Rancid Bread crust

Aromatic taste sensation associated with Meat complex/lean/brothy Cooked pork lean Oxidised vegetable oil Bready/yeasty

Taste (score out of 8) Sweet Bitter Acid Salt Umami

Taste associated with Sweet taste (sucrose solution) Bitter taste (quinine solution) Sour taste (citric acid solution) Salty taste (sodium chloride solution) Monosodium glutamate solution

Texture (score out of 8) Juiciness Tenderness Number of chews

Texture associated with Juiciness perceived during chewing Oral perception of sample disintegration during the first 2–3 bites Number of chews to the point of swallowing

Odour (presence) Cardboard Linseed oil Rubber Sulphur

Odour associated with Wet cardboard Linseed oil Rubber from a car tyre Warm boiled egg white

Flavour (presence) Vegetable oil Fish Nut Metal Caramel Pig

Flavour associated with Fresh canola oil Water from canned sardines Whole hazel nuts Metallic taste/aftertaste (ferrous sulphate solution) Caramel (caramelised sugar solution) Pig and its environment

experimental design balanced out the effect of order of presentation and the first order-carry over-effect (MacFie, Bratchell, Greenhoff, & Vallis, 1989). All assessments took place in a panel room with individual booths illuminated by red lighting. Panellists consumed Melba toast and water prior to evaluating each sample. Each panel member evaluated the samples at individual speed using Fizz Réseau (Biosystèmes, 2008) computerised data acquisition program. 2.11. Statistical analyses

2.10.4. The trained panel Panelists (10) were recruited from a pool trained in descriptive analysis using the Spectrum® intensity scaling method (Meilgaard, Civille, & Carr, 2007) and standard references. Panelist training was based on published standards and guidelines (ASTM, 1995; ASTM International, 2008). Training involved nine 1 h sessions of descriptive term familiarisation, intensity scales usage and performance measures allowing for improvement of panel homogeneity, ability to discriminate and repetitiveness of both the panel and the individual members. The panel evaluated a series of 24 attributes (Table 1). A modification of the Quantitative Descriptive Analysis (QDA®) was used (Meilgaard et al., 2007) for the first thirteen attributes, being ranked on an 8-point structured line scale from “absent” to “strong”. The last ten characteristics were noted on a five point scale of absent, barely perceptible, weak, moderate and strong. The panel was encouraged to describe any other characteristics observed, that is, characteristics that had not been included in the training, and to express comments. The 30 min evaluation sessions were held 1–2 times/week at 10 am (a total of 15 sessions). A balanced incomplete block design was used so that at each session eight samples were presented comprising two each of the combinations of ageing × meat type. Sex was randomised. The samples were presented monadically and in a randomised order. The

The effects of ageing, meat type, sex and their interactions were tested by analysis of variance ANOVA using the GLM procedure of the SAS system (SAS, 2007). Significant interactions were investigated by performing ANOVA for each level of an effect in the interaction term. Significant differences were determined by the Duncan multiple comparison test. Pearson correlation coefficients were calculated with the CORR procedure of the SAS system with values associated with the animal for the sensory and laboratory data. 3. Results 3.1. Laboratory measures The results of laboratory measures are presented in Table 2. Fat oxidation was below the levels of detection and therefore considered absent and not included in Table 2. Sarcomere length measures were all ≥1.58 μm indicating that none of the pork was cold shortened (Dransfield & Lockyer, 1985). Significant differences in pork characteristics were observed for exudate, lightness (L*) and cooking loss with meat type, for yellowness (b*) and shear force with ageing, and for protein content with sex. Exudate, cooking loss and lightness were all

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Table 2 Objective measures of the pork loins according to meat type and ageing (means with standard deviations in parentheses below; significant differences, P b 0.05, shown in bold). Overall

pH Exudate (%) L* a* b* IMF (%) Protein (%) Moisture (%) Sarcomere length (nm) Shear force (kg) Cooking loss (%) Number of animals Number of castrates Number of females

5.94 (0.23) 0.21 (0.17) 53 (4) 11 (1) 17 (6) 2.58 (0.85) 23.4 (0.8) 73.2 (0.8) 2.01 (0.17) 2.8 (0.7) 20.8 (2.9) 40 22 18

Meat type

Ageing

P values

Export

5 days, 3.1 °C

43 days, − 1.7 °C

Castrate

Female

Meat type

5.88 (0.16) 0.27 (0.17) 55 (3) 11 (1) 17 (6) 2.45 (0.80) 23.5 (0.7) 73.1 (0.8) 1.97 (0.18) 2.7 (0.7) 21.9 (2.7) 20 8 12

5.99 (0.28) 0.16 (0.15) 51 (5) 11 (1) 17 (6) 2.72 (0.90) 23.3 (0.8) 73.3 (0.8) 2.05 (0.15) 2.9 (0.6) 19.8 (2.8) 20 14 6

5.96 (0.27) 0.20 (0.18) 53 (5) 11 (1) 13 (3) 2.55 (0.94) 23.6 (0.7) 73.1 (0.8) 2.00 (0.17) 3.1 (0.7) 21.5 (3.5) 20 12 8

5.91 (0.19) 0.22 (0.17) 54 (4) 11 (1) 22 (5) 2.61 (0.78) 23.3 (0.8) 73.3 (0.8) 2.03 (0.17) 2.5 (0.6) 20.2 (2.1) 20 10 10

5.97 (0.28) 0.18 (0.16) 53 (5) 11 (2) 17 (7) 2.73 (0.93) 23.2 (0.8) 73.2 (0.7) 2.03 (0.19) 2.8 (0.7) 20.9 (3.0) 22 22 0

5.89 (0.15) 0.26 (0.18) 54 (3) 11 (1) 18 (6) 2.41 (0.74) 23.7 (0.6) 73.1 (0.9) 1.99 (0.15) 2.8 (0.7) 20.8 (2.9) 18 0 18

0.290

0.494

0.902

0.046

0.960

0.274

0.017

0.346

0.762

0.900

0.432

0.383

0.829

b 0.001

0.902

0.533

0.662

0.429

0.906

0.328

0.019

0.453

0.811

0.747

0.205

0.873

0.684

0.370

0.011

0.467

0.011

0.288

0.500

greater in the domestic than export pork. The pork aged 43 days at −1.7 °C was more yellow and tender than that aged 5 days at 3.1 °C. Sex influenced only the protein content which was higher in the meat from the females than from the castrates. An interaction was observed among all three variables (meat type, ageing and sex) for moisture content (P= 0.015). The pork from female pigs that had been aged seven days at 3.1 °C had lower moisture content for domestic than export quality (72.7% compared to 73.9%, respectively). Some significant correlations were observed among the laboratory measures (Table 3). Correlations of particular note are decreased exudate, cooking loss and lightness with increased pH, increased exudate with cooking loss and decreased moisture and protein contents with increased IMF content. 3.2. Sensory evaluation The sensory scores and presence notes of the grilled, roasted and shabu shabu pork are presented in Table 4. All sensory scores were low. The profiles of the meat differed with cooking method. Most of Table 3 Significant correlations observed among objective measures of domestic and export quality pork subject to two ageing methods. Variable 1

Variable 2

Correlation coefficient (r)

Significance

pH pH pH Exudate L* L* L* a* a* b* IMF IMF IMF

Exudate L* Cooking loss Cooking loss a* Shear force Cooking loss b* Shear force Protein Protein Moisture Sarcomere length

− 0.31 − 0.59 − 0.55 0.48 − 0.33 − 0.32 0.52 0.36 0.39 − 0.32 − 0.43 − 0.66 0.32

⁎ ⁎⁎⁎ ⁎⁎⁎ ⁎⁎ ⁎ ⁎ ⁎⁎ ⁎ ⁎ ⁎ ⁎⁎ ⁎⁎⁎ ⁎

⁎⁎⁎ P b 0.001. ⁎⁎ P b 0.01. ⁎ P b 0.05.

Sex

Domestic

Ageing

Sex

the attributes (meat odour and flavour, pork flavour, acid taste and linseed oil odour notes) were weaker in the shabu shabu than the roasted and grilled pork, but the salt taste and the sulphur odour Table 4 Sensory evaluation of the pork loins cooked by three different methods (means with standard deviations in parentheses; significant differences, P b 0.05, shown in bold). Grilled

Roasted

Meat odour Pork odour Meat flavour Pork flavour Rancid flavour Bread crust flavour Sweet taste Bitter taste Acid taste Salt taste Umami taste Tenderness Juiciness Number of chews

Scores out of 8 3.37 (0.30)a 3.16 (0.33) 3.74 (0.23)a 3.52 (0.29)a 0.04 (0.09) 0.12 (0.07)a 0.08 (0.14) 0.28 (0.16) 0.44 (0.25)a 0.38 (0.08)a 1.29 (0.32) 4.17 (0.78) 2.28 (0.36)a 23.3 (2.2)

Shabu shabu

P values

3.28 3.37 3.52 3.45 0.08 0.04 0.07 0.19 0.49 0.38 1.06 3.89 1.89 24.2

Cardboard odour Linseed odour Rubber odour Sulphur odour Vegetable oil flavour Fish flavour Nut flavour Metal flavour Caramel flavour Pig flavour

Maximum of 5 0.18 (0.19) 0.05 (0.10)ab 0.01 (0.05) 0.01 (0.02)a 0.13 (0.19) 0.00 (0.02) 0.07 (0.14) 0.16 (0.25) 0.20 (0.26)a 1.05 (0.70)

Total notes

Notes out of 100 total possible 8.53 (2.36) 7.25 (2.68) 7.95 (2.67)

0.109

Panellists making notes

Out of a panel of 10 members 5.60 (1.55)a 4.87 (1.44)b

0.028

(0.42)a (0.39) (0.21)b (0.28)a (0.10) (0.10)b (0.13) (0.14) (0.39)a (0.14)a (0.46) (0.84) (0.41)b (2.0)

2.85 3.19 3.13 3.22 0.03 0.01 0.09 0.16 0.27 0.44 1.05 4.28 2.20 24.1

(0.45)b (0.77) (0.35)c (0.44)b (0.07) (0.05)b (0.13) (0.33) (0.19)b (0.14)b (0.70) (0.79) (0.41)a (2.7)

b 0.001 0.156 b 0.001 0.001 0.057 b 0.001 0.471 0.055 0.007 0.005 0.089 0.118 b 0.001 0.535

possible 0.26 (0.29) 0.10 (0.18)a 0.03 (0.11) 0.01 (0.00)a 0.05 (0.11) 0.01 (0.03) 0.05 (0.09) 0.21 (0.29) 0.01 (0.02)b 1.44 (0.9)

0.17 0.03 0.39 0.07 0.08 0.02 0.03 0.23 0.06 1.55

(0.25) (0.08)b (0.26) (0.15)b (0.12) (0.08) (0.08) (0.26) (0.18)b (1.41)

0.170 0.046 0.406 0.017 0.194 0.482 0.592 0.610 b 0.001 0.092

5.73 (1.54)a

Different superscripts denote significant differences across a row for meat type or ageing (P b 0.05).

T.M. Ngapo et al. / Meat Science 92 (2012) 330–337

notes were strongest in the shabu shabu pork. The juiciness was weakest in the roast pork which also had the least number of panellists who made presence notes. While very low scores were attained for linseed oil odour, these scores were highest in the roast pork. The grilled pork had the strongest meat and bread crust flavour scores and caramel flavour notes. No sex effects were observed in the roasted and shabu shabu scores (Pb 0.05). However, when grilled, pork from the castrates was more tender, had a stronger bread crust flavour and fewer chews were required to swallow the pork than that from females (Table 5). In the grilled pork, sex and meat type interactions were observed influencing the salt taste (P= 0.016) and cardboard odour (P= 0.040). The salt taste was stronger in the castrates than females when of export quality (0.39 and 0.33 out of 8.00 for castrates and females, respectively), but weaker in the domestic quality (0.34 and 0.41, respectively). The cardboard odour of the pork from female pigs was stronger than from castrates (0.32 and 0.09, respectively) in the export quality only. The ageing method influenced a number of pork characteristics when cooked by grilling and shabu shabu (Table 6), but not by roasting. When grilled, the pork was more tender, pork odour was weaker, sweet taste and caramel flavour were stronger, more panellists made notes and a greater number of notes were obtained for the pork that had been stored 43 days at −1.7 °C than for 5 days at 3.1 °C. Interactions (ageing× meat type) showed that the ageing effect on the pork odour was only significant for the domestic quality meat (3.48 after 5 days at 3.1 °C compared to 2.92 after 43 days at −1.7 °C, P b 0.05). The number of notes and panellists making notes were also influenced by interactions (sex × meat type× ageing, P b 0.05). A greater number of panellists made notes and more notes were obtained on the domestic pork from castrates chilled 43 days at −1.7 °C (7.0 and 11.7 for panellists and total notes, respectively) than 5 days at 3.1 °C (3.8 and 5.4, respectively). In addition, when aged for 5 days at 3.1 °C, more notes were obtained for the pork from the females (8.4) than the castrates (5.4). And, pork chilled 43 days at −1.7 °C obtained more notes for the domestic (11.7) than export (9.1) quality. When the shabu shabu method of cooking was used, meat odour and pork flavour were weaker in the pork that had been stored 43 days at −1.7 °C than for 5 days at 3.1 °C. While no particular note was stronger with the longer ageing period, more notes were observed overall and more panellists made notes. The pork flavour was influenced by a three-way interaction (sex × meat type × ageing, P b 0.05) such that the domestic pork from castrates had a weaker pork flavour after 43 days at − 1.7 °C than after 5 days at 3.1 °C (2.88 and 3.67, respectively). Furthermore, the pork from castrates after 5 days at 3.1 °C had a stronger pork flavour in the domestic than export quality (3.67 and 2.96, respectively). The roast pork showed effects only of meat type (Table 7). For all four characteristics affected (meat and pork odours and flavours) the export quality pork had weaker scores than the domestic quality. Interactions (sex × meat type × ageing) showed that the pork odour was weaker in the export than the domestic quality pork from castrates after 5 days at 3.1 °C or from females after 43 days at −1.7 °C. Many significant correlations were observed between laboratory measures and sensory scores (Table 8) of which more relationships with grilled pork (25) were significant than with roast (15) or

Table 6 Significant effects (P b 0.05) of ageing on sensory scores of grilled and shabu shabu pork (out of 8). Sensory scores 5 days, 3.1 °C

43 days, − 1.7 °C

Grilled Pork odour (out of 8) Sweet taste (out of 8) Tenderness (out of 8) Caramel flavour (out of 8) Total notes (out of 100) Panellists making notes (of 10)

3.30 0.05 4.00 0.10 7.40 5.10

3.01 0.11 4.34 0.29 9.65 6.10

Shabu shabu Meat odour (out of 8) Pork flavour (out of 8) Total notes (out of 100) Panellists making notes (of 10)

2.98 3.32 7.00 5.14

2.71 3.12 8.91 6.32

shabu shabu (18). Many of the scores were low, yet some trends are evident. Of particular note, for all three cooking methods, tenderness increased with increasing pH and decreasing cooking loss. The roast pork claimed most of the correlations with exudate, but none with IMF content. Two thirds of the IMF correlations, and half of the pH, were related to shabu shabu meat. With increasing pH, meat odour and flavour and acid taste decreased and tenderness increased. Tenderness negatively correlated with shear force in the grilled pork and the number of chews required to swallow positively correlated with shear force when both grilled and roasted. 4. Discussion Both loins from an animal were required to provide sufficient meat to undertake the laboratory analyses, sensory evaluation using three cooking methods and consumer evaluation. Due to the logistics of obtaining both loins from a given animal in a commercial abattoir environment, the sex of the animal was unknown at meat collection and on-line measures were unable to be made. In order to maintain the same conditions that the pork exported to Japan is subjected to, the packaging was not opened until after ageing. The sex of the animal was determined from aged meat samples and the pH and colour were measured at 7 or 45 days p.m. As this is the time that the client would obtain the pork, be it the Canadian consumer or the Japanese importer, these measures might be considered more relevant than on-line measures and while perhaps not directly comparable to other research projects where on-line measures are made, comparisons are able to be made within the project. Drip loss was unable to be measured and instead the exudate of the entire loin was noted upon opening the packaging at 7 or 45 days p.m. Pork for the Japanese market is sorted based on marbling score and colour along the loin surface, and firmness to the touch at the loin ends. Laboratory analyses showed that the domestic and export meat qualities were only significantly different for lightness, exudate and cooking loss (P b 0.05). The export quality meat was darker than domestic quality, as was sought by the sorting process. The exudate and cooking loss were less in the export than domestic quality.

Table 7 Significant effects (P b 0.05) of meat type on sensory scores of roast pork (out of 8).

Table 5 Significant effects (P b 0.05) of sex on sensory scores of grilled pork.

Sensory scores (out of 8)

Sensory scores

Bread crust flavour (out of 8) Tenderness (out of 8) Number of chews

335

Castrate

Female

0.13 4.43 22.6

0.09 3.84 24.2

Meat odour Pork odour Meat flavour Pork flavour

Domestic

Export

3.51 3.60 3.64 3.56

3.06 3.14 3.40 3.33

336

T.M. Ngapo et al. / Meat Science 92 (2012) 330–337

Table 8 Significant correlations observed between objective measures and sensory scores. Variable 1

Variable 2

Correlation Significance coefficient (r)

pH pH pH pH pH pH pH Exudate Exudate Exudate Exudate Exudate Exudate L* L* L* L* L* a* a* a* a* a* a* b* b* IMF IMF IMF IMF IMF IMF IMF IMF IMF IMF IMF IMF Protein Protein Protein Moisture Moisture Sarcomere length Shear force Shear force Shear force Shear force Shear force Shear force Cooking loss Cooking loss Cooking loss Cooking loss Cooking loss Cooking loss Cooking loss Cooking loss

Meat odour (shabu shabu) Meat flavour (shabu shabu) Acid taste (grill) Acid taste (shabu shabu) Tenderness (grill) Tenderness (roast) Tenderness (shabu shabu) Pork odour (roast) Pork flavour (roast) Bitter taste (roast) Umami taste (grill) Umami taste (roast) Tenderness (shabu shabu) Bread crust flavour (grill) Acid taste (grill) Acid taste (roast) Umami taste (grill) Tenderness (shabu shabu) Meat flavour (grill) Tenderness (grill) Tenderness (roast) Juiciness (grill) Number of chews (grill) Number of chews (roast) Pork odour (grill) Number of chews (roast) Pork odour (shabu shabu) Meat flavour (grill) Bread crust flavour (shabu shabu) Sweet taste (grill) Bitter taste (shabu shabu) Acid taste (shabu shabu) Umami taste (shabu shabu) Tenderness (grill) Tenderness (shabu shabu) Juiciness (shabu shabu) Number of chews (grill) Number of chews (shabu shabu) Bitter taste (shabu shabu) Umami taste (shabu shabu) Number of chews (grill) Meat flavour (grill) Sweet taste (grill) Salt taste (roast) Sweet taste (grill) Acid taste (roast) Tenderness (grill) Juiciness (grill) Number of chews (grill) Number of chews (roast) Pork odour (roast) Sweet taste (shabu shabu) Acid taste (grill) Umami taste (grill) Tenderness (grill) Tenderness (roast) Tenderness (shabu shabu) Juiciness (roast)

− 0.35 − 0.37 − 0.62 − 0.35 0.42 0.41 0.44 0.39 0.42 0.45 0.43 0.34 − 0.39 0.38 0.48 0.33 0.40 − 0.41 − 0.32 − 0.54 − 0.36 − 0.47 0.50 0.41 − 0.34 0.33 0.43 0.45 0.34 0.40 0.44 − 0.43 0.55 0.34 0.32 0.34 − 0.47 − 0.37 − 0.33 − 0.33 0.35 − 0.35 − 0.37 0.33 − 0.32 − 0.39 − 0.49 − 0.32 0.59 0.44 0.33 0.36 0.43 0.44 − 0.55 − 0.47 − 0.51 − 0.33

⁎ ⁎ ⁎⁎⁎ ⁎ ⁎⁎ ⁎⁎ ⁎⁎ ⁎ ⁎⁎ ⁎⁎ ⁎⁎ ⁎ ⁎ ⁎ ⁎⁎ ⁎ ⁎ ⁎⁎ ⁎ ⁎⁎⁎ ⁎ ⁎⁎ ⁎⁎⁎ ⁎⁎ ⁎ ⁎ ⁎⁎ ⁎⁎ ⁎ ⁎ ⁎⁎ ⁎⁎ ⁎⁎⁎ ⁎ ⁎ ⁎ ⁎⁎ ⁎ ⁎ ⁎ ⁎ ⁎ ⁎ ⁎ ⁎ ⁎ ⁎⁎⁎ ⁎ ⁎⁎⁎ ⁎⁎ ⁎ ⁎ ⁎⁎ ⁎⁎ ⁎⁎⁎ ⁎⁎ ⁎⁎⁎ ⁎

⁎⁎⁎ P b 0.001. ⁎⁎ P b 0.01. ⁎ P b 0.05.

The marbling score sought for export pork to Japan is 2–4 on the NPPC scale (NPPC, 1999). Marbling score is a visual estimation of the IMF and the two are correlated to varying degrees ranging anywhere from, for example, r = 0.57 (Huff-Lonergan et al., 2002) to r = 0.86 (Faucitano, Rivest, Daigle, Lévesque, & Gariépy, 2004). Regardless of these correlations, the marbling score equivalent in IMF content is generally estimated to be of the same range in % as the score itself, in this case about 2–4% IMF. Chemical measures show that the average IMF of the export pork fell within this range at 2.72%. However, the standard deviation (0.90%) illustrates that much variation was observed. Indeed,

the IMF content ranged from 1.3 to 5.4% with one fifth of the loins having less than 2% IMF, as was also observed for the domestic quality pork. In fact, the IMF content was not significantly different for the two meat types (Pb 0.05). While IMF content and marbling score might not be perfectly correlated, this large range in IMF after sorting likely reflects the crude estimate of marbling score employed. The NPPC standards are intended for use on a cut surface of muscle, but cutting the loin, especially in a central position, is not an option commercially and hence the estimation is made along the entire length of the uncut loin. For as long as importers and competitors are using the same measure of marbling score, this low cost method of marbling estimation might be considered acceptable. Nevertheless, the large variation achieved highlights a potential competitive advantage of employing a reliable on-line method, if or when such a method exists, to guarantee a range or minimum of IMF, particularly in a high value market. Although the aim of the sorting process is to yield a meat fulfilling the requirements of the Japanese importer, the laboratory measures suggest that the meat qualities of the domestic and export quality pork are actually very similar. Therefore, not surprisingly, the trained sensory panel did not observe effects of meat type on the grilled or shabu shabu pork, except as interactions with sex and ageing. The panel did, however, find that when roasted, meat and pork odours and flavours were weaker in the export than the domestic quality pork. Depending on the objective of the assessment in a given study, the cooking method can be used to achieve different types of information from a trained panel. Good all round sensory analysis with a focus on appearance, flavour, and texture has been suggested by pan-frying steaks, whereas a more detailed description of variations in texture attributes is achieved by roasting at a low temperature (Bejerholm & Aaslyng, 2003). This study showed that the largest differences in odour and flavour, which were highly correlated, was caused by the cooking technique illustrating how comparisons of meats that have been cooked using different methods may produce erroneous conclusions. But not only does the cooking method influence the sensory characteristics of meat, the final core temperature is also an important parameter. Bejerholm and Aaslyng (2003) reported that a core temperature of 65 °C was preferable for a focus on flavour components, whereas 75 °C was recommended for discrimination of samples based on overall sensory properties. Taking into consideration the eating quality parameters tenderness, juiciness, flavour and abnormal flavour, Wood, Nute, Fyrsey, and Cuthbertson (1995) recommended a core temperature of 72.5 °C as ideal for grilled chops and 75 to 80 °C for roast pork. The latter contrasts the earlier recommendations of Heymann, Hedrick, Karrasch, Eggeman, and Ellersieck (1990) of at least 71.1 °C and no more than 76.6 °C as the end point temperature for fresh pork roasts founded on minimising pink colour in some muscles and maximising other sensory characteristics and yield of cooked meat. In the present study, the core meat temperature of 72 °C was chosen as a compromise of suggested optimal temperatures for roasting and grilling. And in order to maximise the sensory information attained, the evaluations were undertaken using three cooking methods, roasting, grilling and shabu shabu. Shabu shabu is a Japanese dish prepared by submerging a very thin slice of meat in a pot of boiling water or broth and moving it back and forth several times. Traditionally, beef was the meat of preference, but nowadays other meats are used, including pork. The name shabu shabu directly translates to “swish swish”, the sound of the movement of the meat in the water. Shabu shabu appears to simulate boiling rather than roasting or grilling, and so this method was included for comparison of the effects of cooking method on the sensory quality. In contrast to the meat type, ageing had significant effects (Pb 0.05) on the sensory quality when grilled or shabu shabu, but not when roasted. Shabu shabu pork had weaker meat odour and pork flavour when aged 43 days at −1.7 °C than 5 days at 3.1 °C. When grilled, the pork odour was also weaker after 43 days at −1.7 °C, but only for the domestic quality meat. In addition, grilled pork at the longer ageing

T.M. Ngapo et al. / Meat Science 92 (2012) 330–337

period had stronger sweet taste and caramel flavour, was more tender, and obtained more notes as well as panellists making notes. Caramel and sweet flavours perceived during grilling can be attributed to the formation of Maillard reaction-derived compounds as a consequence of the high temperatures the surface of the grilled pork is subjected to. Overall, the trained panel findings show a trend of weaker pork and meat flavours and odours in the Canadian pork found in the export (Japanese) than the domestic market as a result of either the quality (if roasted) or ageing (if grilled or shabu shabu). In addition, when grilled, more tender pork, stronger sweet taste and caramel flavour, and a greater total number of sensory notes (which individually are not necessarily significant), were observed with the longer ageing period. 5. Conclusions Pork sorted on-line for the Japanese market was only different from that for the domestic market for lightness, exudate and cooking loss; no differences in IMF content were observed. One fifth of the export loins had less than 2% IMF content. These findings likely reflect the crude estimate of marbling score employed on the sorting process highlighting a potential competitive advantage of employing a reliable on-line method, if or when such a method exists, to guarantee a range or minimum of IMF. Overall, the trained panel showed a trend of weaker pork and meat flavours and odours in the Canadian pork found in the export (Japanese) than the domestic market as a result of either the quality (if roasted) or ageing (if grilled or shabu shabu). Grilled pork was also more tender, sweeter and had stronger caramel flavour with the longer ageing period. Acknowledgements The authors would like to acknowledge the financial and in-kind support provided by the Alberta Livestock Industry Development Fund (Project 2007F005R), the Fédération des Producteurs de Porcs du Québec (FPPQ), the Centre de Développement du Porc du Québec Inc. (CDPQ), and Olymel S.E.C/L.P. The authors would also like to acknowledge the technical assistance of J.-P. Daigle, H. Fecteau and P. McSween of CDPQ, M. Beaudet, R. Gatineau, M. Gaudreault, N. Graveline, N. Guertin, M. Hallé, Dr A. Houde, R. Lapointe, S. Provencher, C. Turcotte, L. Vachon and the trained sensory panel of Agriculture and Agri-Food Canada (AAFC), and C. Chénard, Dr J. Garwood, J. Duchesne, M. Lamothe of Cintech and their team. Sincere thanks are also extended to Olymel S.E.C/L.P. who provided the pork and particularly to P.-P. Martin, J. Leclair and the Vallée Jonction team for meat collection and valuable technical advice. References Aasen, E., & Medrano, J. F. (1990). Amplification of the ZFY and ZFX genes for sex identification in humans, cattle, sheep and goats. Bio/Technology, 8, 1279–1281. AOAC International (2005). Official methods of analysis of AOAC International (18th ed.). Gaithersburg, USA: AOAC International. ASTM (1995). FlavLex, Version 1.15. In G. V. Civille, & B. G. Lyon (Eds.), American Society for Testing and Materials. West Conshohocken, PA, USA: Softex Inc.

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