Identification of sensory attributes, instrumental and chemical measurements important for consumer acceptability of grilled lamb Longissimus lumborum.

In this study, important eating quality attributes that influence consumer liking for grilled lamb loin have been identified using preference mapping techniques. The eating quality attributes identified as driving the consumer liking of lamb loin steaks were "tenderness", "sweet flavour", "meaty aftertaste", "roast lamb flavour" and "roast lamb aftertaste". In contrast, the texture attribute "rubbery" and the flavour attributes "bitter flavour" and "bitter aftertaste" had a negative influence on consumer perceptions. Associations were observed between eating quality and a number of instrumental and chemical measurements. Warner Bratzler Shear Force showed an association with "rubbery" texture and a negative association with "tenderness" and consumer liking scores. The compounds, glucose, glucose-6-phosphate, inosine, inosine monophosphate and adenosine monophosphate were associated with the attributes, "sweet flavour","meaty aftertaste", "roast lamb flavour", "roast lamb aftertaste" and with consumer scores for liking of lamb which is probably caused by the role some of these compounds play as precursors of flavour and as taste compounds.

Effects of replacing grass silage with maize silages differing in inclusion level and maturity on the performance, meat quality and concentrate-sparing effect of beef cattle.

The effects of maturity of maize at harvest, level of inclusion and potential interactions on the performance, carcass composition, meat quality and potential concentrate-sparing effect when offered to finishing beef cattle were studied. Two maize silages were ensiled that had dry matter (DM) concentrations of 217 and 304 g/kg and starch concentrations of 55 and 258 g/kg DM, respectively. Grass silage was offered as the sole forage supplemented with either 4 or 8 kg concentrate/steer daily or in addition with one of the two maize silages at a ratio 0.5 : 0.5, on a DM basis, maize silage : grass silage supplemented with 4 kg concentrate daily. The two maize silages were also offered as the sole forage supplemented with 4 kg concentrate/steer daily. The forages were offered ad libitum. The six diets were offered to 72 steers (initial live weight 522 s.d. 23.5 kg) for 146 days. There were significant interactions (P < 0.05) between maize maturity and inclusion level for food intake, fibre digestibility and daily gain. For the grass silage supplemented with 4 or 8 kg concentrate, and the maize silages with DM concentrations of 217 and 304 g/kg offered as 0.5 or 1.0 of the forage component of the diet, total DM intakes were 8.3, 9.8, 8.9, 8.2, 9.2 and 9.8 kg DM/day (s.e. 0.27); live-weight gains were 0.74, 1.17, 0.86, 0.71, 0.88 and 1.03 kg/day (s.e. 0.057); and carcass gains were 0.48, 0.73, 0.56, 0.46, 0.56 and 0.63 kg/day (s.e. 0.037), respectively. Increasing the level of concentrate (offered with grass silage), maize maturity and level of maize inclusion reduced (P < 0.05) fat b* (yellowness). The potential daily concentrate-sparing effect, as determined by carcass gain, for the maize silages with DM concentrations of 217 and 304 g/kg offered as 0.5 and 1.0 of the forage component of the diet were 1.3, -0.3, 1.3 and 2.4 kg fresh weight, respectively. It is concluded that the response, in animal performance, including maize silage is dependent on the stage of maturity and level of inclusion in the diet. Maize silage with a DM of 304 g/kg offered ad libitum increased carcass gain by 31%, because of a combination of increased metabolizable energy (ME) intake and improved efficiency of utilization of ME, and produced carcasses with whiter fat.

Red meat from animals offered a grass diet increases plasma and platelet n-3 PUFA in healthy consumers.

Red meat from grass-fed animals, compared with concentrate-fed animals, contains increased concentrations of long-chain (LC) n-3 PUFA. However, the effects of red meat consumption from grass-fed animals on consumer blood concentrations of LC n-3 PUFA are unknown. The aim of the present study was to compare the effects on plasma and platelet LC n-3 PUFA status of consuming red meat produced from either grass-fed animals or concentrate-fed animals. A randomised, double-blinded, dietary intervention study was carried out for 4 weeks on healthy subjects who replaced their habitual red meat intake with three portions per week of red meat (beef and lamb) from animals offered a finishing diet of either grass or concentrate (n 20 consumers). Plasma and platelet fatty acid composition, dietary intake, blood pressure, and serum lipids and lipoproteins were analysed at baseline and post-intervention. Dietary intakes of total n-3 PUFA, as well as plasma and platelet concentrations of LC n-3 PUFA, were significantly higher in those subjects who consumed red meat from grass-fed animals compared with those who consumed red meat from concentrate-fed animals (P < 0·05). No significant differences in concentrations of serum cholesterol, TAG or blood pressure were observed between groups. Consuming red meat from grass-fed animals compared with concentrate-fed animals as part of the habitual diet can significantly increase consumer plasma and platelet LC n-3 PUFA status. As a result, red meat from grass-fed animals may contribute to dietary intakes of LC n-3 PUFA in populations where red meat is habitually consumed.

Production performance and meat quality characteristics of sheep comprising four sex-types over a range of slaughter weights produced following commercial practice.

Eighty four lambs comprising four sex-types (entire rams, castrated rams, vasectomised rams and entire ewes) were distributed equally into seven target slaughter weights (32, 36, 40, 44, 48, 52 and 56kg). All lambs were born in early spring. Dams and lambs were out on pasture until late September when they were housed and fed concentrate and hay. At birth, ram lambs were heavier than ewe lambs (P<0.01) and gained weight faster (P<0.05). The three male sex-types were similar in birth weight, growth rate and dressing out percentage (P>0.05), and were significantly lower than ewes in dressing out percentage (P<0.001). The m. longissimus dorsi (LD) from all sex-types were similar in initial pH, ultimate pH and sarcomere length (P>0.05) but differed in cooking loss and shear force (P<0.05). The LD from ewes were lower in cooking loss than those from the male sex-types (P<0.05), and recorded smaller shear force values (P<0.05). The average a(∗) values (redness) of the LD was highest in ewes and differed only from that of vasectomised rams (P<0.05). Ewes were also highest in oxymyoglobin proportion (P<0.05). Although correlations between most meat quality parameters and slaughter weight were highly significant (P<0.001) the correlation coefficients (r) were generally small.

The effects of grain treatment, grain feed level and grass silage feed value on the performance of and meat quality from, finishing beef cattle.

A completely randomised design study involving 132 continental crossbred beef steers was undertaken to evaluate the effects of method of grain treatment and feed level, and grass silage feed value on animal performance, carcass characteristics and meat quality of beef cattle. Winter wheat was harvested and the grain was stored either ensiled crimped and treated with 4.5 l/t of a proprietary acid-based additive (crimped), ensiled whole and treated with 20 kg feed-grade urea per t (urea) or stored conventionally in an open bin treated with 3 l propionic acid per t. Two grass silages, of contrasting feed value (L and H) were ensiled. For the conventional, crimped and urea treatments, grain dry matter (DM) concentrations were 802, 658 and 640 g/kg, respectively. For the L- and H-feed value silages, DM concentrations were 192 and 240 g/kg and D values were 671 and 730 g/kg DM, respectively. The silages were offered as the sole forage supplemented with either conventional, crimped or urea-treated grain-based concentrate at either 3.5 or 6.0 kg DM per steer per day. The grain supplement consisted of 850 and 150 g/kg DM of grain and citrus pulp, respectively. For the conventional, urea and crimped treatments, DM intakes were 8.85, 9.43 and 9.04 kg/day (standard error (s.e.) = 0.129); estimated carcass gains were 0.60, 0.55 and 0.61 kg/day (s.e. = 0.020), respectively. For the low- and high- feed value grass silages, estimated carcass gains were 0.56 and 0.61 kg/day (s.e. = 0.014), respectively. For the low and high grain feed levels, estimated carcass gains were 0.56 and 0.61 kg/day, respectively. Grain treatment, grain feed level or silage feed value did not alter (P > 0.05) meat quality, lean colour or fat colour. There were significant silage feed value × grain feed level interactions (P < 0.05) for final live weight (LW) and daily live-weight gain (DLWG). Increasing grain feed level increased final LW and DLWG when offered with the low-feed value silage, however, grain feed level had no effect on final LW or DLWG when offered with the high-feed value silage. It is concluded that urea treatment of grain increased silage intake and feed conversion ratio (kg DM intake per kg carcass) and tended to decrease carcass gain. Crimping provides a biologically equally effective method to store grain as conventional methods. Improving grass silage feed value had a greater impact on animal performance than increasing grain feed level by 2.4 kg DM per day.

The effect of enamel porcelain thickness on color and the ability of a shade guide to prescribe chroma.

OBJECTIVE: To test the null hypothesis that there is no color change when enamel porcelain thickness is changed and to evaluate the ability of a shade guide to prescribe chroma. METHODS: Three shades (3M1, 3M2 and 3M3) were selected from a Vitapan 3D master shade guide. Five disk specimens were prepared for each shade, consisting of three layers (opacious dentin, dentin and enamel) at thicknesses of 0.6, 0.8 and 0.6mm, respectively. The color of each disk was measured using a spectrophotometer. Enamel porcelain was reduced in thickness to 0.3mm and porcelain disks were remeasured. RESULTS: Reducing the enamel thickness of porcelain disk specimens significantly increased L) (p<0.05), b*, metric chroma and hue angle (p<0.001). For the three shades studied (3M1, 3M2 and 3M3) L* values were not significantly different (p>0.05) and chroma increased for 3M1 with the lowest chroma to 3M3 with the highest chroma, which is in line with the shade guide specifications. Although statistically significant (p<0.001) changes in hue angle between the three shades were small (less than 3 degrees overall). The difference in chroma between the three shades 3M1, 3M2 and 3M3 was greatest for the thin enamel layer than the thick enamel layer. SIGNIFICANCE: A change in enamel thickness from 0.6 to 0.3mm resulted in a three-unit change in L* and metric chroma and a 4 degrees change in hue angle. A change in enamel porcelain thickness will have a greater effect on higher chromatic shades than those with lower chroma. The ability of the shade guide to prescribe chroma was demonstrated but this could be offset by an anomalous enamel thickness.

Intramuscular lipid and fatty acid profile of sheep comprising four sex-types and seven slaughter weights produced following commercial procedure.

The intramuscular lipid and fatty acid profiles of the m. longissimus dorsi from 84 sheep comprising four sex-types (enire ram, vasectomised ram, wether and ewe) and seven slaughter weights (32, 36, 40, 44, 48 and 52kg) were measured. Animals were reared following the commercial practice. Specifically, they were fed pasture and a concentrate diet, and age at slaughter ranged from 180 to 390 days. Differences between entire and vasectomised rams, and between wethers and ewes in intramuscular lipid content were not significant (P>0.05). However, entire and vasectomised rams were significantly lower (P<0.05) in intramuscular lipid content than ewes and wethers. Sex related differences in 14:0 (myristic acid), t18:1, c18:1, t18:2 and c18:2 proportions were not significant (P>0.05). Ewes and wethers were similar in 16:0 (palmitic acid) and 18:0 (stearic acid) proportions, but ewes contained significantly higher 16:0 and lower 18:0 proportions than entire and vasectomised rams (P<0.01). Entire and vasectomised rams recorded the highest c18:3 proportions, wethers were intermediate whilst ewes contained the lowest proportion (P<0.01). Although neither saturated fatty acid (SFA) nor monounsaturated fatty acid (MUFA) proportions varied with sex-type, vasectomised rams contained significantly higher polyunsaturated fatty acid (PUFA) proportion that the other sex-types (P<0.05). Whilst intramuscular lipid content, and 18:0 and c18:1 proportions were linearly correlated with slaughter weight (P<0.001), 14:0 and c18:3 proportions decreased quadratically with increasing slaughter weight (P<0.001). The vasectomised ram and the entire ram were similar in fatty acid profile, except the significantly higher PUFA proportion recorded by the vasectomised ram.

Effects of replacing grass silage with either maize or whole-crop wheat silages on the performance and meat quality of beef cattle offered two levels of concentrates.

A randomised design involving 66 continental cross beef steers (initial live weight 523 kg) was undertaken to evaluate the effects of the inclusion of maize or whole-crop wheat silages in grass silage-based diets on animal performance, carcass composition, and meat quality of beef cattle. Grass silage was offered either as the sole forage or in addition to either maize or whole-crop wheat silages at a ratio of 40:60, on a dry matter (DM) basis, alternative forage: grass silage. For the grass, maize, and whole-crop wheat silages, DM concentrations were 192, 276, and 319 g/kg, ammonia-nitrogen concentrations were 110, 90, and 150 g/kg nitrogen, starch concentrations were not determined, 225, and 209 g/kg DM and in vivo DM digestibilities were 0.69, 0.69, and 0.58; respectively. The forages were offered ad libitum following mixing in a paddle type complete diet mixer wagon once per day, supplemented with either 3 or 5 kg concentrates per steer per day, in two equal feeds, for 92 days. For the grass, grass plus maize and grass plus whole-crop wheat silage-based diets food intakes were 8.38, 9.08, and 9.14 kg DM per day, estimated carcass gains were 514, 602, and 496 g/day and carcass weights were 326, 334, and 325 kg; respectively. Altering the silage component of the diet did not influence carcass composition or meat eating quality. Increasing concentrate feed level tended ( P = 0.09) to increase estimated carcass fat concentration and increased sarcomere length ( P < 0.05), and lean a* ( P < 0.01), b* ( P < 0.05), and chroma ( P < 0.01). There were no significant silage type by concentrate feed level interactions for food intake, steer performance, carcass characteristics or meat eating quality. It is concluded that replacing grass silage with maize silage increased carcass gain, and weight due to higher intakes, and improved utilisation of metabolisable energy. Whilst replacing grass silage with whole-crop wheat silage increased live-weight gain, the reduced dressing proportion resulted in no beneficial effect on carcass gain, probably due to increased food intakes of lower digestible forage increasing gut fill. Meat quality or carcass composition were not altered by the inclusion of maize or whole-crop silages in grass silage based diets.

Beef production potential of Norwegian Red and Holstein-Friesian bulls slaughtered at two ages.

There is a paucity of data on the beef production potential of Norwegian Red (NOR) compared with 'modern' Holstein-Friesian (HF) cattle. The present study used a total of 64 bulls in a 2 × 2 factorial design study encompassing two breeds (HF and NOR) and two slaughter ages (485; E, and 610; L, days). The mean initial age and live weight of the HF bulls were 179 (s.d. 47.1) days and 203 (s.d. 64.0) kg, while the corresponding data for the NOR bulls were 176 (s.d. 39.7) days and 185 (s.d. 63.6) kg, respectively. Bulls were offered a 50 : 50 mixture (dry matter (DM) basis) of grass silage and concentrates. No breed × slaughter group interactions were recorded for any parameters evaluated (P > 0.05). HF bulls had higher (P < 0.001) DM intake and poorer (P < 0.01) efficiency of conversion of food to carcass gain than NOR bulls. HF bulls tended (P = 0.07) to have a higher rate of live-weight gain and were heavier (P < 0.001) at slaughter than NOR bulls, though both carcass weight and rate of carcass gain did not differ between the breeds (P > 0.05). NOR bulls had higher (P < 0.001) dressing proportion and carcass conformation score than HF bulls, while breed of bull had no influence (P > 0.05) on carcass fat classification, depth of subcutaneous fat, marbling score or on the weight of fat in the internal depots. Daily food intakes did not differ (P > 0.05) across the two slaughter age groups, though efficiency of conversion of food to carcass gain was poorer (P < 0.05) in the L compared with E bulls. Rate of live-weight gain was lower (P < 0.01) for L bulls, although rate of carcass gain did not differ (P > 0.05) between the E and L bulls. Increasing age at slaughter increased (P < 0.01 or greater) dressing proportion, carcass fat class, depth of subcutaneous fat, marbling score and internal fat depots, but had no effect (P > 0.05) on the carcass conformation score. Instrumental measures of meat quality indicated that meat from NOR bulls was tougher (P < 0.01) than meat from HF bulls, while delaying slaughter increased (P < 0.001) a* and C*ab, and decreased (P < 0.01) h0, indicating improved redness. It is concluded that NOR bulls have higher food efficiency and produce more highly conformed carcasses than HF bulls, but HF bulls produce more tender meat.

The use of digital imaging for colour matching and communication in restorative dentistry.

OBJECTIVE: To develop a shade matching method based on digital imaging and to compare observers' ability using this method with the conventional one set against a spectrophotometric 'gold standard'. METHODS: Two Vita Lumin shade guides were used in this study, nine shades being selected from the first Vita Lumin shade guide, A2, A3, A3.5, B2, B3, B4, C1, C2 and C3. A second shade guide was used to match the selected shades. A Nikon Coolpix 990 digital camera with Nikon SB21B ring flash was used to record the digital images of the shade tabs of the two shade guides and the images were processed using Adobe Photoshop software. A total of 27 samples (three replicates of each shade of the nine tabs selected) were matched with a digital shade guide prepared from the digital images of the second shade guide by 10 observers on a computer screen (computerised matching method). The 10 observers also matched the same shade tabs using the conventional matching method simulated in a phantom head. In addition, colour values were obtained from the digital images using Adobe Photoshop and quantified according to an internationally recognised scale as CIELAB colour values, L*,a*,b*. The relationship of the digitally derived CIELAB values to the CIELAB values obtained using a reflectance spectrophotometer was investigated. RESULTS: The cross tabulation statistical analysis showed a statistically significant difference (p<0.001) between the conventional method and the computer method with a 43% and 61.1% correct match respectively. There was also a statistically significant difference between observers in both methods (p<0.001 and p<0.04 for the conventional and computer methods respectively). A statistically significant high correlation of the CIELAB colour values were found between both colour measurement methods (p<0.001). CONCLUSION: The observers' shade matching performance was significantly better with the computer method compared with the conventional one. There was a large variation in the observers' matching ability. The digital camera can be used as a means of colour measurements in the dental clinic.

Interrelationships amongst carcass and meat quality characteristics of sheep.

The relationships between various carcass and meat quality characteristics of sheep were studied. Relationships were determined by regression, using data obtained from sheep belonging to a wide range of breeds, sex types and slaughter weight (32-62 kg). The chilling rate of the M. longissimus dorsi (LD) post-mortem was negatively correlated with carcass weight (r=-0.42, P<0.01), back fat thickness (r=-0.54, P<0.001) and the cooking loss of the M. infraspinatus (IS) muscle (r=-0.44, P<0.001). Correlation between chilling rate and shear force of the IS muscle was not significant, which was also the case between chilling rate and the cooking loss and shear force of the LD and M. triceps brachii muscles. A positive relationship was observed between total collagen and cooking loss (r=0.34, P<0.05) and between heat-insoluble collagen and cooking loss of the LD muscle (r=0.37, P<0.01). Generally collagen content was positively correlated with lean content and negatively with fat content. Carcass weight was significantly (P<0.001) correlated with intramuscular fat (r=0.61), moisture (r=-0.76), cooking loss (r=-0.49), shear force (r=-0.41) and hue angle (r=-0.41). Shear force was positively associated with cooking loss (r=0.42, P<0.001), but negatively with intramuscular fat content (r=-0.55, P<0.001). Cooking loss was positively correlated with moisture content (r=0.55, P<0.001).

The effect of food deprivation prior to slaughter on performance, behaviour and meat quality.

The effects of repeated food deprivation, prior to slaughter, on performance, feeding behaviour and meat quality of pigs was examined. Three experimental treatments were compared. In treatment 1 pigs had ad libitum access to feed up to the point of loading on the day of slaughter. Treatment 2 involved a 12-h fast prior to slaughter and treatment 3 involved a 20-h fast prior to slaughter. Pigs were slaughtered on a weight basis therefore each pen was emptied over a period of weeks. This meant some pigs experienced repeated food deprivation. The feeding pattern of pigs which were deprived of food for 12 h was very similar to that observed before feed restriction. Pigs which were deprived of food for 20 h spent significantly more time at the feeder post fasting. This was particularly marked during the first 2-3 h when access to feed was restored. Feed deprivation for 12 h prior to slaughter did not adversely affect performance, carcass weight, meat quality or welfare in the present study. Fasting for 20 h reduced carcass weight by 1 kg, which was not statistically significant but could result in financial losses related to carcass weight. The negative effects on meat quality, of repeated feed deprivation, resulted from slower growth rates rather than feed deprivation per se.

In vivo measurement of colour changes in natural teeth.

It has been observed that teeth become lighter when they are dried. The present study was designed to quantify these changes and the time taken for tooth colour to return to normal. The colour of an upper central incisor in each of seven subjects was measured using a reflectance spectrophotometer before and after application of a rubber dam and, in another seven subjects before and after taking a polyvinylsiloxane impression. There were statistically significant changes in the L*, a* and b* values following rubber dam application and in the L* value following impression taking. The results demonstrate that teeth become brighter and less colour saturated after rubber dam application and brighter after impression taking. The original values were regained after 30 min.

The use of discriminant analysis for the interpretation of the reflectance spectra of irradiated porcine M. longissimus dorsi.

Slices of porcine M. longissimus dorsi were packed in overwrap packs and subjected to irradiation (0 and 5 kGy) and then stored for 7 days at 4°C. Reflectance spectra were measured on the outside surface and a freshly cut surface at 7 days post irradiation. The reflectance spectra were transformed to reflex attenuance, k/s and first and second difference spectra and subjected to discriminant analysis. Using discriminant analysis it was possible to establish a calibration equation to discriminate between the spectra of irradiated and unirradiated pork for both the outside and the inside surface. When the calibration model was used to predict the classification of new samples a 100% correct grouping was obtained for the freshly cut surface, however, for the outside surface the classification ranged from 87 to 100% correct depending on the mathematical transformation of the reflectance spectra. This shows the potential of colour measurements as a possible rapid initial screening test for the identification of irradiated pork. Evaluation of the first difference spectra to identify peak positions showed significant differences in peak positions between irradiated and unirradiated pork. The position of the peaks in the irradiated sample is discussed as lending support to the hypothesis of the carboxyhaem form as the irradiated pigment.

The effect of ionising radiation on the colour of beef, pork and lamb.

The effect of irradiation (0 and 5 kGy) of beef, pork and lamb portions in retail overwrap packs and subsequent storage at 4°C was studied in relation to colour changes. The colour of the exterior surface of beef and pork was measured on the same samples on each day of storage for up to 7 days post irradiation. On day 7 the colour of a freshly cut surface was measured. The colour of both the exterior and a freshly cut surface of lamb, in similar retail overwrap packs was measured at 2, 5 and 7 days, post irradiation, different samples being used on each day of measurement. L* values of irradiated beef increased significantly with storage and a* values for unirradiated samples decreased significantly with storage. For lamb there was a general increase in L* and h(o) values and a decrease in a*, b* and C* values with storage. Analyses of the day 7 data showed statistically significant effects for species on all CIELAB parameters. Irradiation resulted in significantly higher hue angle (h(o)) values and the a*, b* and C* values were significantly higher on the exterior than freshly cut surface. There were a number of statistically significant 2 factor and 3 factor interactions. The role of formation of a carboxyhaem pigment in the colour of irradiated meat is discussed. The problem of interpretation of pigment changes from CIELAB values is highlighted.

The effect of ionising radiation on the colour of leg and breast of poultry meat.

The effect of irradiation (0 and 5 kGy) of chicken, goose and turkey breast and leg muscles and subsequent storage at 4°C was studied in relation to colour changes. The colour of the outside surface was measured on the breast on each day of storage for up to 7 days post irradiation and for breast and leg and day 7. The colour of a freshly cut interior surface of both breast and leg was measured after 7 days storage. L* values of control and irradiated chicken, goose and turkey breast muscles changed little during storage post irradiation. The a* values for unirradiated goose breast were significantly higher than irradiated goose breast but declined to values similar to irradiated goose breast after 7 days of storage. The b* values for irradiated turkey breast were significantly higher than unirradiated turkey breast at all times post irradiation treatment. Analysis of variance was performed on the day 7 CIELAB values of breast muscle for the effects of species, surface and irradiation and their interactions. After 7 days storage a* values of poultry breast were higher on the freshly cut surface due to irradiation in all species, with decreases in hue angle due to irradiation. The a* values of leg of all species at 7 day post irradiation was significantly higher in the irradiated treatment than the controls. The results for the turkey leg indicate that this effect may be mainly due to higher a* values of the freshly cut surface. The possible role of carboxy form of the haem pigments as the irradiated pigment form is discussed.

The effect of increasing carcass weight of finishing boars and gilts on joint composition and meat quality.

Two hundred and eighty-eight crossbred (3/4 Landrace × 1/4 Large White) pigs, comprising equal numbers of boars and gilts, were housed in single sex groups from 50 kg liveweight to slaughter at liveweights of 92, 105, 118 and 131 kg (carcass weights of 70, 80, 90 and 100 kg). Sample joints from the left longissimus dorsi muscle were obtained at slaughter for dissection and meat quality assessment. As carcass weight increased there were significant (p<0.001) increases in eye muscle area and subcutaneous fat content. Lean content decreased (p<0.001) with increasing carcass weight while intermuscular fat content was not affected. There was a significant interaction between carcass weight and gender with % drip loss in pork from gilts at 100 kg having a higher drip loss than boars and gilts at all other weights. There were small but significant (p<0.01) reductions in ultimate pH with increasing carcass weight. Cooking loss was also reduced (p<0.001) at the heavier weights. There was no effect of carcass weight on shear force or on intramuscular fat. Dry matter (DM) and crude protein (CP) contents of m. L. dorsi increased (p<0.001) at heavier weights while sarcomere length decreased (p=0.001). Compared with boars, gilts had greater eye muscle area (p<0.05), more subcutaneous fat (p<0.001). Meat from gilts in comparison with boars had higher % DM and % CP contents (p<0.001), higher intramuscular fat content and shear force (p<0.05). It is concluded that meat quality may be improved when carcass weight is increased from 70 to 100 kg. ©

Some observations on the absorption spectra of various myoglobin derivatives found in meat.

The three principal myoglobin states of haem pigment, oxymyoglobin, metmyoglobin reduced myoglobin, and the ferrous nitrous oxide form, nitrosomyoglobin, were prepared as pure pigments in solution. The absorbance spectra of these solutions were determined and extinction coefficients calculated. The position of the absorption peaks showed some small differences compared to published data, in particular the use of absorbance readings at 525 nm as an isobestic point for all three could be questioned. The use of mathematical transforms to first or second difference functions showed merit for the identification of mixtures of some of the myoglobin forms. The second difference function separated the broad absorbance band in the Soret region into two separate troughs, thereby resolving a mixture of oxymyoglobin and reduced myoglobin. It is suggested that based on absorption spectra, similar mathematical transforms could be applied to the interpretation of reflectance spectra of meat and meat products. Further evaluation of such mathematical transformations is required on a range of meat reflectance spectra.

Oxymyoglobin formation in meat and poultry.

The rate of oxymyoglobin formation (blooming) was estimated, by reflectance spectrophotometry and depth of oxygen penetration, of beef and pork 1. dorsi and chicken breast muscles of normal ultimate pH. Although beef bloomed very rapidly when exposed to air, even at 23°C, pork muscle exhibited little evidence of oxymyoglobin formation at this temperature and no chicken muscle produced oxymyoglobin at 23°C. Even after 48 h at 5°C there was little evidence of oxymyoglobin formation in the chicken muscles although formation was evident in the pork samples. After only 24 h storage at 5°C it was apparent that both the chicken and pork muscles oxidised to produce some metmyoglobin at their surface, though the amount produced was apparently more in the chicken than the pork samples. In most chicken samples held in air at 5°C the predominant pigments were the purple reduced myoglobin and brown metmyoglobin. The implication of these observations in relation to the packaging of chicken portions is discussed.