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This study aimed to determine how small heat shock proteins (sHSPs) protect myofibrillar proteins from μ-calpain degradation during ageing. Immunoprecipitation experiments with M. longissimus dorsi (LD) from Angus heifers (n = 14) examined the interaction between αβ-crystallin, desmin, titin, HSP20, HSP27 and μ-calpain. Results showed that αβ-crystallin associated with desmin, titin, HSP20, HSP27 and μ-calpain. Exogenous αβ-crystallin reduced desmin and titin degradations in myofibrillar extracts and attenuated μ-calpain activity. In a second experiment, bull LD (n = 94) were aged at -1.5°C for up to 28 days post mortem. μ-Calpain autolysed faster in high ultimate pH (pH(u)) meat (pH(u)≥6.2) and this was concomitant with the more rapid degradation of titin and filamin in this pH(u) group. Desmin stability in intermediate pH(u) meat (pH(u) 5.8 to 6.19) may be due to the protection of myofibril-bound sHSPs combined with the competitive inhibition of μ-calpain by sHSPs.

A primary goal of Earth system modelling is to improve understanding of the interactions and feedbacks between human decision making and biophysical processes. The nexus of land use and land cover change (LULCC) and the climate system is an important example. LULCC contributes to global and regional climate change, while climate affects the functioning of terrestrial ecosystems and LULCC. However, at present, LULCC is poorly represented in global circulation models (GCMs). LULCC models that are explicit about human behaviour and decision-making processes have been developed at local to regional scales, but the principles of these approaches have not yet been applied to the global scale level in ways that deal adequately with both direct and indirect feedbacks from the climate system. In this article, we explore current knowledge about LULCC modelling and the interactions between LULCC, GCMs and dynamic global vegetation models (DGVMs). In doing so, we propose new ways forward for improving LULCC representations in Earth system models. We conclude that LULCC models need to better conceptualise the alternatives for upscaling from the local to global scale. This involves better representation of human agency, including processes such as learning, adaptation and agent evolution, formalising the role and emergence of governance structures, institutional arrangements and policy as endogenous processes and better theorising about the role of teleconnections and connectivity across global networks. Our analysis underlines the importance of observational data in global-scale assessments and the need for coordination in synthesising and assimilating available data.

Bull Musculus longissimus dorsi (n=63) were categorised into high (pH≥6.2), intermediate (pH 5.8-6.19) and low (≤5.79) ultimate pH (pHu) and aged up to 28 days post mortem at -1°C. High pHu samples were acceptably tender at 1 day post mortem and significantly more tender than low pHu meat at all ageing timepoints (p

The eating quality of meat is a result of complex interactions between the biological traits and biochemical processes during the conversion of muscle to meat. It was hypothesised that muscles inevitably engage towards apoptotic cell death due to the termination of oxygen and nutrient supply to the muscle following exsanguination. Thus, factors that regulate the process of apoptotic cell death of muscle cells are believed to ultimately influence meat quality. Proteomic studies have associated the regulation of small heat shock proteins (sHSPs) with various meat quality attributes including tenderness, colour, juiciness and flavour. Due to the anti-apoptotic and chaperone functions of sHSPs, they are proposed to be involved with the eating quality of meat. In this review, we discuss the possible chaperone and anti-apoptotic role of sHSPs during the conversion of muscle to meat and consider the repercussions of this on the development of meat tenderness.

Lamb has a unique flavor, distinct from other popular red meats. Although flavor underpins lamb's popularity, it can also be an impediment to consumer acceptance. Lack of familiarity with sheepmeat flavor itself can be a barrier for some consumers, and undesirable feed-induced flavors may also compromise acceptability. Against the backdrop of climate uncertainty and unpredictable rainfall patterns, sheep producers are turning to alternatives to traditional grazing pasture systems. Historically, pasture has been the predominant feed system for lamb production in Australia and around the world. It is for this reason that there has been a focus on "pastoral" flavor in sheep meat. Pasture-associated flavors may be accepted as "normal" by consumers accustomed to meat from pasture-fed sheep; however, these flavors may be unfamiliar to consumers of meat produced from grain-fed and other feed systems. Over the past few decades, studies examining the impacts of different feeds on lamb meat quality have yielded variable consumer responses ranging from "no effect" to "unacceptable", illustrating the diverse and sometimes inconsistent impacts of different forages on sheepmeat flavor. Despite considerable research, there is no consensus on which volatiles are essential for desirable lamb aroma and how they differ compared to other red meats, for example, beef. In contrast, comparatively little work has focused specifically on the nonvolatile taste components of lamb flavor. Diet also affects the amount of intramuscular fat and its fatty acid composition in the meat, which has a direct effect on meat juiciness and texture as well as flavor, and its release during eating. The effect of diet is far from simple and much still needs to be learned. An integrated approach that encompasses all input variables is required to better understand the impact of the feed and related systems on sheepmeat flavor. This review brings together recent research findings and proposes some novel approaches to gain insights into the relationship between animal diet, genetics, and sheepmeat quality.

Marine fish, hoki (Macruronus novaezealandiae), kahawai (Arripis trutta) and trevally (Pseudocaranx dentex) were used to develop fermented fish models to emulate Asian examples. The formulations comprised ground fish, carbohydrate, garlic and salt, but no added culture. The carbohydrate was cooked rice or glucose. The mixtures were extruded into open-ended 50 mL plastic syringes, sealed and incubated at 30℃ for 96 h. The syringe piston was progressively advanced to yield test samples. The endogenous lactic acid bacteria were capable of fermenting glucose, but not cooked rice. After glucose fermentation, the treatments contained around 8.7 log cfu·g-1 (from 3.3) with the pH range of 4.38 to 5.08 (from around 6.3), depending on the species. Hardness, springiness and cohesiveness of treatments all increased with fermentation, except for hoki, which was subject to an endogenous proteolytic activity. Color development varied with species: light reflectance (L*) of the trevally and kahawai treatments increased, while the a* (redness) and b* (yellowness) values were static. Hoki exhibited the least color changes except for yellowness, which increased markedly. Possible reasons for this are discussed. Proteolysis was greatest for trevally. Lipid oxidation was least for hoki, notably the species with the lowest fat content. The trevally treatment generated the highest concentration of amines, but values were lower than reported for fermented fish sausage in Asia, possibly because of raw material hygiene status. The physiochemical outcomes indicated that trevally (as pieces unsuited for sale as fillets) would be best suited to this food product class. Suitable species could be identified in other fisheries.

Wild-catch eels with low fat content are either not accepted at all or accepted as a lower-quality and less valuable product in the global eel market. This study was undertaken with the goal of increasing the fat content of yellow shortfin eel, Anguilla australis (104 ± 11 g initial weight), captured in the wild and kept in captivity for a short period, as well as assessing their rate of growth. An 86-d feeding trial was conducted indoors in a recirculation aquaculture system, at 25.5 ± 1.6 C. Two commercial extruded dry feeds were tested; one formulated for European eel and one not specifically intended for use on eels. Good values of specific growth rate (1.10 and 1.12%/d) and feed conversion ratio (1.01 and 1.10) were achieved with both tested feeds. At the end of the trial, eels achieved 20–22% total fat, starting from wild fish with 7% fat content. Fat quality of the fattened eel was appreciably superior (higher proportion of omega-3 fatty acids) than the fat of eels captured in the wild. The results of this study are encouraging for the prospect of fattening yellow shortfin eels and obtaining a market-oriented eel product.

UNLABELLED Goat milk fat includes several branched chain fatty acids (BCFAs), like 4-methyloctanoic acid, which when free, are responsible for goaty flavor. This flavor limits the market opportunities for goat milk. Prior research showed that cyclodextrins (CDs) can reduce goaty flavor, presumably by binding free fatty acids. This research extends that observation. In odor ranking trials in citrate buffer at pH 4.8, β-CD concentrations between 0% and 0.35% were increasingly effective in reducing odor intensity due to 4-methyloctanoic acid, but only when present in high molar excess. α-CD was also effective, but γ-CD was not. In lipase-treated goat milk only β-CD was effective but at much lower molar excess, a difference potentially explained by several factors. One was that BCFAs bind to CDs in marked preference to their straight chain isomers. Displacement experiments with phenolphthalein disproved that hypothesis. The ability of β-CD to reduce goaty flavor intensity extended to yogurt. An analytical panel showed that flavor of goat yogurt was reduced by addition of β-CD, but only if added before heating and fermentation. A hedonic trial showed that consumers preferred unsweetened and sweet/vanilla-flavored goat yogurt more when β-CD was included, P = 0.004 and 0.016, respectively. Males liked all yogurts more than females (P < 0.01), but there was a treatment × gender interaction (P = 0.016) for sweet/vanilla yogurt: sweet/vanilla masked the goaty flavor for males but not females. This results parallels previously demonstrated gender effects for sheepmeat flavor caused by BCFAs. PRACTICAL APPLICATION β-Cyclodextrin masks goaty flavor in yogurt, and with its GRAS status means it could be used in commercial goat yogurts and similar products so the real or perceived nutritional advantages of goat milk are not lost to goaty flavor.

Elvers and glass eels of Anguilla anguilla were fed diets containing two types of feeding stimulants (FS) that were based on processed marine (MBFS) and yeast proteins (YBFS). Elvers (1.5 ± 0.3 g) were fed seven diets (MBFS and YBFS diets at 20 g kg−1, 40 g kg−1 and 60 g kg−1 plus control) for 60 days. Glass eels (250 ± 100 mg) were weaned to 60 g kg−1 MBFS, 60 g kg−1 YBFS and control diets for 30 days. Diets containing 60 g kg−1 FS had a beneficial effect in terms of growth, homogenous size distribution and feed intake in elvers. Elvers fed 60 g kg−1 MBFS and YBFS diets grew 11.9% and 5.6% faster than the control group. No differences in growth and size distribution were detected in glass eels fed 60 g kg−1 MBFS and YBFS diets. However, FS affected the digestive system maturation; fish fed the 60 g kg−1 MBFS and YBFS diets showed higher and intermediate values in the specific enzyme activities in comparison with the control group. This study revealed that the incorporation of FS into a pelleted diet was beneficial on the overall performance of European glass eels and elvers. However, the observed results were different depending on the eel’s stage of development, as well as the type and inclusion level of the FS.

The concept of geographical exclusivity prompted an exploratory survey with toasted woods other than oak to flavor wine. A total of 11 woods and oak (Quercus alba) were cut into chips 20 × 10 × 2.5 mm and toasted at 200 °C for 2 h (light toast) or 210 °C for 3 h (dark). Weight losses and changes in CIE color space were monitored. The toasted chips were infused in unoaked chardonnay (5 g L−1) for 2 wk. Parallel infusions were done with model wine (water, ethanol, tartaric acid) adjusted to pH 3.5. Ultraviolet absorbances due to infusion were recorded on the basis that that lignin compounds and their potential pyrolysates are based on phenolic structures that absorb in the ultraviolet range. Weight losses on light and dark toasting were highly variable between species as were color changes, suggesting potential for different flavor outcomes from chemical changes. Ultraviolet absorbance curves were also highly variable showing that different species yielded different quantities of potentially flavor-active phenolic compounds in real and model wine. More absorbing matter was extracted from the light toast treatments, and light toast oak, which demonstrated the greatest weight loss on light toasting, yielded the widest range of ultraviolet-absorbing matter. In an informal sensory trial with the 24 species/toast combinations infused in chardonnay all but one wood, Cupressus macrocarpa, resulted in flavors reminiscent of oaked wines. A hedonic consumer trial with 4 species and oak compared with uninfused chardonnay showed that each of the 4 had potential as a flavorant. Thus, woods unsuited to barrel construction could provide unrealized flavor opportunities in the wine industry, and could extend to flavoring spirits. Practical Application: This is about using toasted wood chips of species other than oak to enhance wine flavor. A wide range of species unsuited to barrel construction was toasted and tested for compounds that extract into wine. Informal and formal sensory trials showed that most woods had the potential to impart desirable flavors to wine.

This article reports the perception of cooked, nitrite-cured sheepmeat sausage that included 1.5% glucose, sucrose, xylose, or no sugar addition. The 4 sugar treatments were dry-cooked, vacuum packed, and stored chilled, and were hedonically assessed after 0, 1, and 2 mo. Consumers were advised that they could be eating any 1 of beef, chicken, lamb, pork, or turkey, in a salted cured preparation. Three-way analysis of variance (ANOVA) showed that liking of appearance, color, and texture were unaffected by sugar treatment, whereas liking of aroma, flavor, sweetness, and overall liking were markedly and significantly increased by xylose. Storage time as a factor had minimal effects on liking. In contrast, all attributes were liked more by male consumers (57%, P < 0.001). When asked to identify the meat species, lamb was correctly identified 50% of the time. With xylose, the observed frequency of lamb's misidentification as beef increased by 50% above the expected Chi-square frequency. This was largely at the expense of observed lamb selection frequency, which was 18% below expectation. When data were segregated by gender, the misidentification remained significant for males (P = 0.002), but was not significant for females (P = 0.32). The misidentification of beef for lamb may be due to the generation of Strecker aldehydes in the Maillard reaction between xylose and meat amino acids, which were shown to be greatly increased in the headspace above xylose-treated sausage. The restriction of significant misidentification to males is less easy to explain but may be associated with the possible greater sensitivity of females to volatile fatty acids, which are components of sweat.

Five-carbon sugars affect cooked meat flavor by the Maillard reaction. This research extends to the effects of pH and cooking temperature on meaty and species flavor, sweetness, barnyard, and rancid flavor in sheepmeat. Glucose and xylose were each blended into ground longissimus meat to 0%, 0.5%, or 1% and heated to 75 °C. Xylose treatments browned more than glucose treatments, and xylose flavor effects were more marked. With xylose, sheepmeat flavor declined significantly, but meaty flavor also declined. Differences were marked between pH 5.93 and 6.52, but pH effects at lower pHs were more subtle. Sweetness increased in many treatments, suggesting that 75 °C did not fully exploit the Maillard reaction. Therefore, pressure-cooked casserole treatments, chilled and frozen, were used to study the effects of xylose, packaging, and storage time on flavor. There were no flavor differences due to chill packaging (foil laminate compared with barrier bag) (not significant). Xylose addition reduced sheepmeat flavor by 24% on the 1 to 9 intensity scale (P < 0.001), while meaty flavor and sweetness were unaffected. Rancid flavor was reduced by xylose addition (P < 0.01), and the reduction in barnyard flavor approached significance (P= 0.07). Chilled storage time to 29 d did not affect any attribute. In the frozen casserole trial (stored exposed to air), xylose had no significant flavor effects (all P≥ 0.38). However, storage to 71 d increased the rancid flavor score from a negligible 0.06 to 0.60 (P= 0.04), suggesting that rancidity development swamped more subtle effects.

A comprehensive set of quality parameters has been recorded for meat and fat from groups of castrate and ram lambs raised on pasture and slaughtered in groups of six at 91‐day intervals from 122 to 668 days of age. These include mechanical evaluation of meat tenderness, sensory evaluations of meat flavour and fat odour, and measurements of fat colour, fatty acid composition, vitamins C and E, free glucose and iron in the meat, and of the concentrations of the flavour compounds indoles, phenols, and branched chain fatty acids in the fat. There was significant variation in many parameters between slaughter days, including markedly lower meat tenderness in one slaughter group, probably in response to unfavourable pasture conditions. Older ram lambs tended to be less tender than castrates of the same age. However, no longer‐term age‐related trends were observed in tenderness or flavour quality. Concentrations of free glucose in rigor muscle and vitamin C showed a declining trend with age. Concentrati...

Longissimus dorsi muscles from six normal- and six high-ultimate pH bulls were selected for fine mincing and subsequent pH adjustment with acid and alkaline pyrophosphate. Four pH treatments were prepared: initially high remains high (mean of pH 6.37), high becomes normal (5.62); initially normal remains normal (5.65), and normal becomes high (6.21). The addition level of phosphate as P(2)O(5) was the same in all replicates. Before pH adjustment, colour and water holding capacity (WHC) values were strongly affected by higher (initial) pH in expected ways: darker, lower chroma, higher capacity. After pH adjustment, these values were affected only by the final pH, not the initial pH (the pH history). Total protein solubility was likewise affected by final pH but not initial pH. In contrast, the combination high initial pH-high final pH improved sarcoplasmic protein solubility by 20% over the combination normal initial pH-high final pH. Sarcoplasmic protein solubility is an indicator of strain required to fracture cooked batters made from the minced meats; in the event, the rank order of the four treatments for strain-to-fracture matched that of sarcoplasmic protein solubility. Statistically, sarcoplasmic protein solubility and strain-to-fracture were both affected by initial pH (P

Food exporters face difficulties in gaining acceptance for products that are unfamiliar to consumers in other cultures. One way of overcoming such resistance may be to make use of that culture's “flavour principles” as a way of making products more familiar. Product labelling may also be used to emphasise aspects of products which consumers within a culture will value. We evaluated liking for, and familiarity of, samples of a product made from lamb for a group of New Zealand and ethnic Chinese, Singaporean consumers. These two groups differ substantially in their consumption of sheepmeat, with Singaporeans consuming it very infrequently. The samples were a relatively unflavoured control product, plus three other samples flavoured with herb/spice combinations typical of Chinese, Indian or European cuisine. Each consumer received one of three different messages regarding the samples to be consumed, with the samples labelled as either: meat, lamb, or lamb, together with a message about the health properties of consuming lamb. Both groups completed a modified Food Choice Questionnaire (FCQ), which contained items related to the importance of health in meat consumption. Despite the relative infrequency of sheepmeat consumption in Singapore, the control sample was rated as most liked for both sets of consumers. The main evidence for the action of culture-specific flavour principles was significantly lower liking and familiarity ratings by the New Zealand than the Singaporean consumers for the Chinese flavoured sample. There was no evidence of the action of the different label information conditions, even where groups were divided according to their ratings on the Health factor of the modified FCQ.

With increasing emphasis on understanding consumer preferences in export markets, particularly in Asia, there is a need to determine those factors that influence food choice in other cultures. The Food Choice Questionnaire (FCQ), which assess the relative importance of nine factors thought to be important motives in food choice: Health, Mood, Convenience, Sensory Appeal, Natural Content, Price, Weight Control, Familiarity, and Ethical Concern , was administered to groups of female consumers in Japan, Taiwan, Malaysia, and New Zealand. The Food Neophobia Scale was also administered in New Zealand, Taiwan and Japan. There was agreement between Taiwanese and (ethnically Chinese) Malaysian consumers in the most important food choice factors: Health, Natural Content, Weight Control and Convenience . In contrast, Price was most important for Japanese consumers and Sensory Appeal for New Zealand consumers. Familiarity was rated as least important by all countries, and Ethical Concern was also considered unimportant by all countries except Japan, where it was rated as relatively important. Older consumers generally gave higher ratings. Differences between consumer groups were also shown in the degree of neophobia. These data are important in demonstrating differing motives for food choice cross-culturally, and also provide indications of which food claims may be useful in promoting choice in the countries studied.

Sheepmeat consumption is uncommon in many Asian countries, whose consumers often complain about the unacceptability of the sheepmeat odour/flavour. Volatile branched chain fatty acids (BCFAs), present in all fatty tissue, have been implicated as the cause of such flavours, as has skatole, which originates from pastoral diets. To determine the relative importance of these compounds to the acceptability of sheepmeat for the Japanese consumer, cooked lean beef samples containing added BCFAs and skatole at three levels (none, low, high), in factorial combinations, were rated for liking by consumers in Japan and New Zealand, and by a trained descriptive analysis panel in terms of aftertaste , barnyard odour and flavour, grassy/pastoral odour and flavour, milky odour and flavour, sheepmeat odour and flavour, sour odour and flavour, and sweet odour and flavour. The consumer and analytical data were analysed using internal preference mapping, which gave a two-dimensional solution. The most important preference dimension was clearly related to the presence of BCFAs, high levels of which were also associated with typical barnyard/milky/sour/sheepmeat flavours. Consumer preference scores were clustered around those products containing the zero level of BCFAs. The presence of different levels of skatole, and the associated grassy and sweet flavours, was less important in explaining variation in consumer responses. ANOVA on the consumer data also confirmed the influence of BCFAs on liking, particularly for the Japanese consumers.

Steers were fed for nine weeks on either ryegrass/clover pasture or maize (six animals per group), to evaluate the effects of diet on attributes of meat and fat. Feed intake was restricted in the grain‐fed group with the intention of producing equivalent growth rates in the two treatment groups, but this resulted in significantly slower weight gain, reduced carcass weight, and reduced subcutaneous and intramuscular fat. Nevertheless, the glycolytic potential (an estimate of pre‐slaughter glycogen) in the M. longissimus dorsi lumborum was approximately 20% higher (P < 0.05) in the grain‐fed cattle, while the ultimate pH of the meat was equivalent for both groups. The results suggest that grain‐based diets can increase muscle glycogen concentrations independent of the higher calorific intake normally associated with grain diets, probably in response to changes in rumen fatty acid production. Compared with grain diet, pasture diet resulted in significantly higher (P < 0.01) muscle tocopherol content...

Sixteen male Comisana lambs were divided into two groups of eight at age 45 days. One group received a commercial pelleted diet (control) and the other group (carob) received a diet in which 20% carob pulp was used in partial replacement of barley. The animals were slaughtered at 100 days. No significant differences were observed for live weight, although the carob group ate 14% more dry matter, showing a higher conversion index (2.68 and 3.22kg dry matter per kg weight gain respectively for control and carob). The dressing percentage was higher (p < 0.05) for the control group; however, the carcasses showed no differences in the European classification system. Lightness (lean colour) was the only meat quality parameter (p < 0.05) affected by diet treatment: the carob group lambs had a higher L (∗) value. This could not be attributed to ultimate pH, which was not significantly different between the two groups. In triangle tests, sensory panelists were unable to distinguish one diet treatment from the other. Instrumental tenderness was also unaffected by diet treatment.

The effects of sheep age and diet on several odours and flavours are described. Ram lambs raised on ewe's milk then a corn-based diet were compared with lambs raised on milk and a pasture of grass/clover, six treatments in all. A seventh treatment comprised very old ewes maintained on pasture. Fat and lean from forequarters was minced and cooked together. Cooked lean was assessed for intensity by a sensory panel for 10 flavour attributes. Four showed significant (P < 0.01) treatment effects: 'sheepmeat', 'animal', 'liver', and 'poultry'. Sheepmeat flavour was highest in the slow-grown pasture-fed lambs. Animal flavour-the flavour associated with the odour of confined livestock-showed a similar pattern with treatment. Liver flavour was highest in ewe meat, and the biochemical origin of this flavour is discussed. Eleven related odour attributes were assessed on the rendered fat with a novel olfactometer. Five attributes showed highly significant treatment effects for intensity (P < 0.001): animal and sheepmeat odours showed a similar distribution to the equivalent flavours; likewise cabbage and rancid odours were associated with the two slow-grown pasture treatments. A comparison of the odour and flavour statistics showed that the sense of smell was the more discriminating in sheepmeat assessment, and also confirmed that fat was the true source of sheepmeat odour/flavour. In respect of sheepmeat production for effective marketing, the data showed that at 90 days, a pastoral diet resulted in slightly enhanced odours when compared with a corn-based diet. By 215 days, however, many undesirable odours were exacerbated. Since these older rams were more sexually developed, a sex rather than an age effect could not be excluded. Rendered fat from this work was further used in a companion study (Yang et al., 1997. Meat Sci., 45, 183-200) in an attempt to link individual volatile compounds to odour attributes.

This paper examines the feasibility of measuring collagen properties by near infrared spectroscopy (NIRS) in ovine Semimembranosus and Biceps femoris muscles. Because collagen concentration within a muscle was rather narrow, the R for collagen concentration was never more than 0.55. By contrast, R for solubility was better, especially for Semimembranosus, always exceeding 0.80. No one scanning method — fiberoptic probe or the in-built transport module — was superior, either in reflectance or transmittance modes. The equations developed were tested for predictive power by cross-validation procedures within muscles and between muscles. In the latter case, Biceps femoris data were used in a Semimembranosus equation and vice versa. The equations worked in any combination. However, there were indications that the correlations were sensitive to the state of the meat, whole tissue or homogenized, although the wavelength range 910 to 950 nm did not vary with sample state.

The gelation of lean meat homogenates was examined in a thermal scanning rheology monitor, a device that non-destructively measures rigidity and elasticity, as response to a repetitive small movement. Salted (NaCl and pyrophosphate) homogenates were scanned from 10°C to 85°C at 1°C/min, continuously or with an isothermal hold period at 25, 35, 45, 50 or 55°C. The intention of isothermal holding was to visualize key features of the gelation process. Whatever the thermal path, the final properties of the gel were substantially the same. This indicates that heat-mediated gelation follows only one path and is complete by 85°C. The hold at 55°C yielded the most information on gelation. During the hold, gelation was very nearly complete while rigidity steadily increased. This showed that transition from the sol state to the gel and rigidity development are separate events. Samples held at 25°C underwent pH-dependent transitions in rheological properties but at higher hold temperatures these transitions were often not observed. They were caused by a progressive loss of pyrophosphate due to an endogenous pyrophosphatase. The pH and temperature dependencies of the transitions were easily explained by classic enzymology. The enzyme activity could be inhibited by 10 mm NaF. Under these conditions the onset of final gelation occurred at a slightly, but significantly, lower temperature. Models to explain this and another subtle effect of pyrophosphate are presented. At a given pH, although gelation is subtly affected by pyrophosphate, the final rigidity and elasticity are much the same in its presence or absence. Pyrophosphate is in near universal use in salted meat products. Presumably its reported advantages, better water-holding capacity and greater gel strength, are not revealed by the thermal scanning technique.

The effects of pre-slaughter administration of antifreeze glycoproteins to lambs were assessed on lamb meat quality after thawing. Various concentrations of antifreeze glycoproteins (AFGP) from Antarctic Cod were injected intravenously into lambs (35 ± 5 kg liveweight) at various times prior to slaughter. The lambs were electrically stunned, slaughtered, then subjected to high voltage electrical stimulation. The rate of glycolysis was assessed by monitoring the rate of pH fall and the ultimate pH. Longissimus dorsi muscles were removed from the carcasses 24 h post-slaughter. Samples were vacuum packed and stored frozen at −20 ° C for 2–16 weeks. Upon thawing, samples were assessed for drip loss and sensory properties (foreign flavour, storage flavour, texture, tenderness, juiciness and overall acceptability). At certain times, frozen samples were examined by scanning electron microscopy after ice sublimation. Injection of AFGP had no effect on the rate of pH decline, and for all treatments the pH of samples was not significantly different. Injection of AFGP 10 min before slaughter had no effect at any of the concentrations of AFGP for any of the factors assessed, suggesting that 10 min was insufficient time for the AFGP to become associated with the muscle tissue. Injection of AFGP at either 1 or 24 h before slaughter reduced drip loss and ice crystal size. Crystals were smallest in the lambs injected to a final concentration of 0.01 μg/kg AFGP, particularly when injected 24 h before slaughter. These results suggest that the addition of AFGP could reduce damage due to frozen storage of meat, if a cost-effective and consumer-acceptable method could be developed to incorporate these proteins into meat prior to freezing.

The objective of this study was to determine effects of pre rigor stretching on beef tenderness development. Beef loins (M. longissimus dorsi; n=24) were assigned to either stretching or non-stretching treatments and aged for 14 days at -1.5 °C. Sarcomere length, shear force, water-holding capacity and proteolysis were determined for the loins at 1, 7 and 14 days of ageing. Stretching increased the length of the loins by 33% resulting in a trend of increasing sarcomere length (P=0.19). However, no significant differences for shear force values, purge, drip and cooking losses between treatments were found. Shear force values decreased with ageing times (P0.05). Western blot assay found that stretching did not affect the extent of desmin degradation. The findings from the present study suggest that pre rigor stretching with the current increase in length will not contribute to tenderness improvement of the beef loins.

Pyridinoline, a mature crosslink of collagen, was measured in intramuscular connective tissue isolated from ovine semimembranosus, a muscle noted for its highly insoluble collagen. Concentration ranged between 0·25 and 0·59 mol/mol of collagen, on the high side of concentrations reported in the literature for this and other muscles in various species. Pyridinoline concentration was inversely related to collagen solubility in muscle homogenates (P < 0·0). In a comparison between semimembranosus, biceps femoris and gluteus medius, pyridinoline concentration was again inversely related to collage solubility. For all these muscles, pyridinoline remained insoluble in a heat-dependent solubility test, but it is argued that pyridinoline does not explain all the solubility properties of ovine intramuscular collagen. Pyridinoline concentration was not significantly correlated with sensory or shear properties of cooked semimembranosus, confirming the importance of other heat-stable crosslinks.

Bull M. longissimus dorsi (n=94) categorised into high (n=28), intermediate (n=14) and low (n=52) ultimate pH (pHu) were aged at -1.5°C for 28days. Shear force was higher and more variable (p0.05) in intermediate pHu samples during ageing. Titin, filamin and desmin degradation was also less extensive in intermediate pHu samples compared to the other two pH categories. The extent of the decline of HSP20, HSP27 and αβ-crystallin concentrations during post mortem ageing was pHu related such that high pHu meat maintained the highest concentration of small heat shock proteins followed by intermediate and low pHu meat. μ-Calpain autolysis was slowest in intermediate pHu and cathepsin B activities remained consistently low during ageing in this group (p0.05). Meat toughness in the intermediate pHu group may be attributed to the combination of a larger pool of sHSP with a sub-optimal cathepsin B activity and intermediary μ-calpain activities.

The hygiene of chicken processing surfaces and retention of the wheat protein gliadin and of protein in general on those surfaces were compared in 15 trials after 3 increasingly rigorous cleaning steps. Eleven different chicken products with wheat derivatives as a batter were prepared on 3 processing lines in 15 production runs selected at random over 6 mo (5 runs were thus replicates). Using surface swabs, surface hygiene was monitored by adenosine triphosphate (ATP) bioluminescence, gliadin by immunoassay, and protein by the Coomassie dye method. Gliadin was monitored in 14 trials, protein in 5, and all trials were monitored by ATP bioluminescence. In a typical trial, gliadin values normalized to uncleaned values fell from 100000 arbitrary units, to 6000 after rinsing, to 30 (foam, rinse), to not detected (sanitize, rinse). Parallel ATP bioluminescence values also decreased, but crucially, the relative gliadin value was less than the relative ATP value after foam and rinse in all 14 trials, a result unchanged after sanitize and rinse. In trials comparing ATP and protein, the relative ATP values exceeded the relative protein values in 4 of 5 trials after foaming and after sanitizing. Thus, for these 11 products, ATP bioluminescence was a surrogate indicator of residual gliadin and probably of residual protein. Absolute gliadin concentration on an uncleaned processing line was also the basis of modeling the risk of cross-contamination of gliadin in follow-up product, where the line was hypothetically left uncleaned between production runs. The results show that all follow-up product could be declared "gluten-free" under proposed legislation, and suggest that some industrial cross-contamination risks are currently overestimated.

Coopworth and Merino lambs were slaughtered at 8 months after being grazed together on ryegrass/clover pasture from weaning. The flavour and odour intensities of the cooked lean (longissimus lumborum muscle) and odour intensity of subcutaneous fat were assessed by an analytical panel. Sheepmeat flavour in the lean was stronger (P < 0.01) in Coopworth and foreign flavour was stronger in Merino (P < 0.001). However, the mean pH of the meats also differed significantly (P < 0.001) (Coopworth, 5.77; Merino, 6.16), thereby confounding the effects of pH and breed. Panellists' comments pointed to a breed effect in subcutaneous fat odour, but means for sheepmeat and foreign odours in the fat were statistically identical. Meat toughness, assessed by the same panel, peaked around pH 6.0, irrespective of breed. In a parallel study of the Merino lambs and five Merino cross breeds, an in-house panel assessed acceptability rather than intensity of meat attributes. All crosses and the pure Merino produced meat ...

Tendon from beef hind leg muscles was used to replace some of the lean in a conventional emulsion formulation. The tendon was homogenized and either used raw or preheated for 2·5 h at a range of temperatures (50, 60, 70, 80°C) before use. Texture analysis and sensory evaluation were performed on cylinders of cooked sausage. Texture analysis was carried out on formulations which had 20% of meat protein replaced by 20% tendons which were raw or had been preheated to 50, 60, 70, or 80°C. Fracturability decreased by about 40% with raw tendon, but was restored to within 20% of the no-replacement control if the tendon had been preheated. Hardness was approximately doubled by replacement with raw tendon or tendon heated at 50°C. At temperatures higher than that, hardness returned to approximately no-replacement levels. For sensory evaluation (0–25% replacement; preheating at 70°C), sausages were assessed by a 12-member panel for texture, flavour and overall acceptability. All attributes decreased with increasing collagen content, the decrease being less marked with preheated tendon. Thus more connective tissue could be added for the same panel score if the tissue was preheated. Comparison of the texture profile and the panel scores for texture at the same lean replacement level suggested that reduced fracturability was the texture parameter that panellists objected to when heated tendon replaced some of the lean. Other researchers have shown that connective tissue preheated to 100°C before addition in emulsion sausages results in improved yields and better sensory attributes, but the present results show that temperatures as low as 60°C can be effective for beef tendon.

The potential of near infrared (NIR) spectroscopy as an on-line method to quantify glycogen and predict ultimate pH (pH(u)) of pre rigor beef M. longissimus dorsi (LD) was assessed. NIR spectra (538 to 1677 nm) of pre rigor LD from steers, cows and bulls were collected early post mortem and measurements were made for pre rigor glycogen concentration and pH(u). Spectral and measured data were combined to develop models to quantify glycogen and predict the pH(u) of pre rigor LD. NIR spectra and pre rigor predicted values obtained from quantitative models were shown to be poorly correlated against glycogen and pH(u) (r(2)=0.23 and 0.20, respectively). Qualitative models developed to categorize each muscle according to their pH(u) were able to correctly categorize 42% of high pH(u) samples. Optimum qualitative and quantitative models derived from NIR spectra found low correlation between predicted values and reference measurements.

The functional properties of whole, diced or minced high and normal pH beef were determined after 0, 1, 2, 3 and 7 month's storage. There was no interaction between pH, degree of comminution and storage time for most of the attributes measured. Regardless of storage time or comminution method, high pH meat had significantly (P0.001) higher sarcoplasmic protein solubility, water holding capacity, cooked batter torsion stress and strain, yield and emulsion stability than normal pH meat. Normal pH meat had significantly (P0.01) higher myofibrillar protein solubility and hue angle than high pH meat. Water holding capacity significantly (P0.01) decreased and hue angle increased with the increase in the degree of comminution. Protein solubility in raw meat and the cooked batter stress, strain, yield and emulsion stability of both high and normal pH meat deteriorated with time. However, this deterioration was faster in the normal pH meat compared to high pH meat except for total and myofibrillar protein solubility. Within the parameters of the present study, it is concluded that frozen high pH meat possesses superior functional attributes compared to normal pH meat regardless of the degree of comminution or storage time.

New Zealand’s geographic position remote from Northern Hemisphere markets is an extra challenge that the meat industry has had to address to remain internationally competitive. Traditionally, New Zealand exported most of its sheepmeat frozen. However, in a drive to market table-ready cuts of beef and lamb, a carbon dioxide controlled atmosphere packaging system was developed so raw product could be shipped chilled (−1.5°C) and yet maintain a hygienic storage life of at least 16 weeks. One advantage of this type of storage is that the meat has sufficient time to tenderize during transport. This process, known as ‘ageing’, is also important for the development of meat flavor (Bouton et al., 1958).

Variations in diet, age and castration were employed to generate a range of flavours that were chemically analysed to find the cause of ‘pastoral’ flavour in sheepmeat and its relationship to species flavour. Lambs were raised on pasture (ram or castrate) or on a maize-based or lucerne-based concentrate diet (ram only). They were slaughtered at 132 and 232 days. Fat from animals raised on concentrates had lower proportions of fat-hardening stearic acid and higher proportions of oxidation-prone fat-softening oleic and linoleic acids. Concentrations of species-characterising short branched-chain fatty acids (BCFAs), typified by 4-methyloctanoic acid, were lower for pasture-fed lambs, particularly at 232 days, although between-animal variation was high. Castration did not statistically affect BCFA concentration at this age. Correlations between BCFAs and testes weight were not significant, suggesting that they were not acting as sex pheromones. Concentrations of 3-methylindole (skatole) in perirenal fat were higher for the pasture diet at both slaughter dates. Concentrations of 4-methylphenol in the fat were not affected by diet. However, 3-methylphenol was more abundant in pasture treatments. A sensory panel found that the intensity of ‘sheepmeat’ flavour was higher for pasture-raised animals, but that associations of ‘barnyard’ flavour (which has been linked to pastoral flavour) with diet were more complex. The issue was resolved by fat sniffing. Panel responses to heated subcutaneous fat were recorded as frequency of descriptive terms drawn from a limited lexicon. Volatiles from fats pooled by treatment were resolved on a gas chromatographic column whose effluent was monitored by odourport sniffing. Compounds were identified by parallel chromatographic/mass spectrometric runs. The headspace concentrations of these compounds were then measured for individual animals. These data were related to frequency data by the principal component method. ‘Mutton’ and ‘sheepmeat’ odour notes were clearly linked to indoles (skatole particularly) and, to a lesser extent, methylphenol, setting these notes apart from ‘lamb’, an odour note more associated with lucerne and maize diets through higher concentrations of BCFAs. It was concluded that 3-methylindole was the major cause of pastoral flavour in sheepmeat, and that fat oxidation products represented a background flavour that varied quantitatively but not qualitatively with fatty acid profile. © 2002 Society of Chemical Industry

A patented method of rapidly determining the ultimate pH from approximate glycolytic potential of muscles of slaughtered animals has been devised. The method is based on the rapid hydrolysis of muscle glycogen to glucose by the enzyme amyloglucosidase and subsequent measurement of the liberated glucose. In acetate buffer at pH 4.5, glucose concentration can be determined in 30 s with domestic meters for diabetes control. The meter response differed from that of glucose in blood, but was linear with concentration. In slurries comprising homogenised meat in acetate buffer and added glucose, a similar linear response was obtained. Amyloglucosidase was capable of rapidly hydrolysing glycogen to glucose in such slurries. In the 24 h following slaughter, a decrease in glycogen, as determined by glucose, occurred in parallel with the decline in pH. At the same time, lactate progressively accumulated as expected. Values for the approximate glycolytic potential and (by calibration) ultimate pH, were obtained on prerigor muscle within 7 min of muscle sampling in an industrial environment. The method is suitable for on-line application in beef abattoirs particularly those employing hot boning where ultimate must be known at the grading point.

A method to measure the approximate glycolytic potential of slaughter animals, and thus the ultimate pH, was applied for several months on the slaughter line of a cattle abattoir. The patented method (WO 00112844) determines a so-called glucose value from the hydrolysis of glycogen in a sample of Longissimus lumborum. The value is available before the dressed carcass is weighed and graded. The 13,700 cattle tested were pasture-fed bulls and 'prime' animals, the latter comprising steers and virgin females. The method was used to sort carcasses into two quality grades, table cuts and manufacturing, according to a threshold glucose value that in this application corresponded to an ultimate pH of 5.70. In frequency distributions the glucose value was roughly normally distributed for prime animals but for bulls was lower on average and strongly skewed to low values. The distributions showed that 19% of prime and 62% of bulls had an ultimate pH below 5.70. The results were consistent with prior survey work undertaken in New Zealand with conventional pH measurements made a day after slaughter. Error in the method is examined with respect to commercial outcomes. For most errors the method 'fails-safe', in that normal pH animals are more likely to be classed as high pH than vice versa. In a second phase of the study, meteorological and some abattoir data are related to mean daily glucose values and their variance. The more bulls slaughtered per day the lower the mean glucose value for bulls (r=-0.25, P

This paper describes the colour properties of seven hot-boned, unstimulated beef striploins during rigor attainment at 9, 14 and 24°C, during blooming at 4°C, and after storage at −1°C for 0, 2 and 8 weeks. Immediately after rigor attainment (0 weeks of storage) full blooming, as judged by L * and chroma, took at least 12 h. After 2 and 8 weeks storage, blooming was complete within about 4 h. The exponential equations describing blooming were different for 0 weeks compared with 2 and 8 weeks. This difference can be explained in terms of oxygen consumption by meat freshly in rigor. At 0 weeks, meat that entered rigor at 24°C had the best bloomed colour, whereas at 2 and 8 weeks the 9°C treatment had the best and the 24°C the worst. The data set, which spanned a range of ultimate pH values and three rigor attainment temperatures, was used to estimate the value of early colour measurements (first 24 h post-rigor) in predicting colour during display several weeks later. As judged by correlation coefficients, early measurements of hue were the only ones useful. L * and chroma were poor predictors. This result, together with the knowledge that blooming is slow in the first 24 h post-rigor, casts doubt on the value of subjective or objective colour assessments made in chillers. Temperature of rigor attainment between 9 and 24°C did not affect the time of browning onset, nor the rate of browning. It was confirmed that meat with lower pH had higher chroma before and after blooming.

The effect of dietary supplementation with clenbuterol for either 8 days or 55 days in lambs was studied. The 55-day treatment was combined with an immediate preslaughter exercise regime. The effect of these treatments on post-mortem calpain system activities, meat ageing and meat quality was studied. Neither short-nor long-term supplementation had an effect on the rate of pH fall post mortem. Short-term supplementation had no effect on the initial nor the final shear force values but these were higher at intermediate times. In contrast, prolonged supplementation increased shear force values at all times post mortem. Preslaughter exercise, while influencing the rate of pH decrease in both control and supplemented groups, did not affect meat tenderness. After short-term clenbuterol-supplementation, the in-vitro μ-calpain activity was significantly lower in the supplemented group at 6 and 24 hr post mortem, while m-calpain and calpastatin activities were largely unaffected. In contrast, 55-day clenbuterol supplementation resulted in significantly higher levels of calpastatin activity at all times post mortem. These data imply that clenbuterol results in toughened meat due to alterations in the calpain/calpastatin system, the mechanisms of which are dependent upon the duration of supplementation.

The effects of lamb age and diet on volatiles from fat are described. Rendered fat from ram lambs raised on ewe's milk then a corn-based diet was compared with that from lambs raised on milk and a pasture of grass/clover, six treatments in all. An additional treatment comprised very old ewes maintained on pasture. Helium-borne volatiles of rendered fat were resolved on a DB5 gas chromatographic column and the mass spectra obtained. Long chain alka(e)nes like neophytadiene were dominant in pasture treatments especially where the lamb growth rate was slow. Branch chain fatty acids (4-methyloctanoic, 4-methylnonanoic and an unidentified acid) were also highest in these treatments. Longer chain aldehydes like 2-undecenal were good indicators of a grain diet. Hexanal, commonly associated with rancid odours, was unaffected by treatment. The diketone 2,3-octanedione was an excellent indicator of a pasture diet, as was 3-methylindole (skatole). Phenols showed complex relationships to treatments, but were generally more common in pasture treatments. Benzenethiol (thiophenol) was unaffected by treatment. Inspection of principal component analysis plots identified 10 volatile compounds as contenders for the cause of sheepmeat odour; branch chain fatty acids were confirmed as the leading chemical class. There were indications that puberty or age caused an increase in the odorous 4-methylnonanoic acid. Animal odour-the odour of confined livestock-was clearly causally linked to 3-methylindole, a rumen breakdown product of tryptophan. 3-Methylindole was also responsible for rancid odour, rather than hexanal and its analogues. A hypothesis is advanced that links 2,3-octanedione formation to the enzyme lipoxygenase and linolenic acid, both abundant in green leafy tissue. Overall, the data confirm that sheepmeat odour/flavour is specifically linked to the branch chain fatty acids, and is probably exacerbated by pasture-derived 3-methylindole and alkyl phenols.

Sheepmeat (the flesh of Ovis aries) is eaten by millions of people all over the world and is probably eaten in every country to some extent. There are no religious or cultural taboos on eating sheepmeat, which contrasts sharply with the taboos that apply to beef (Hindu) and pork (Moslem, Jewish). Nevertheless, many people avoid sheepmeat because they object to its odour (especially during cooking) and/or its flavour. The Chinese even have a special word for the disagreeable cooking odour of sheepmeat, ‘soo’, meaning sweaty, sour (Wong, 1975). Even in those Western countries that have a greater acceptance of sheepmeat, many dislike it, particularly the meat from mature animals with its apparently stronger odour and flavour. Also, the relatively high melting point of sheep fat contributes to a ‘waxy’ mouthfeel that is unacceptable to many. On a cool plate the fat tends to harden rapidly, which contrasts with the more oily character of, say, pork fat.

The effects of cryoprotectant proteins, trivially termed 'antifreeze proteins', from the Antarctic Cod and the Winter Flounder were assessed in meat during chilling and freezing. In light-microscopy studies, bovine muscle (Sternomandibularis) samples were soaked in phosphate buffered saline with and without 0·1 mg/ml antifreeze protein. Samples were then held frozen (-20°C) or chilled (2°C) for 3 days. Samples were freeze-substituted, embedded in resin and sectioned. With antifreeze protein present, transverse sections of frozen samples had many small intracellular spaces, probably representing ice crystals. Frozen controls had much larger intracellular single spaces. Antifreeze protein had no effect on chilled samples. Similarly treated samples were examined by scanning electron microscopy using a cryostage attachment. Chilled ovine muscle samples (Peroneus longus) were soaked for various periods (0-7 days) in 0·9% saline containing various concentrations of antifreeze proteins (0-1 mg/ml). Samples were then held frozen (-20°C) or chilled (2°C) for 5 or 7 days. With frozen samples, antifreeze proteins reduced the size of ice crystals, compared to the control. This effect depended upon the concentration used and the period of soaking before the samples were frozen, but was independent of source. Antifreeze proteins had no effect on chilled samples.

This study examined the effects of curing and oxygen exclusion on the odour and flavour of sheepmeats. One series of experiments examined the effect of curing on the ability of panellists to distinguish between the flavours of lean mince from various species (mutton, beef, pork, chicken). Other experiments examined the effects of curing and of maintaining an anoxic storage/cooking environment on the intensity of mutton flavour and odour, particularly adipose tissue odour. Curing had no effect on panellists' abilities to distinguish between the flavour of mince from different species. Storage and cooking of uncured mutton adipose tissue samples under anoxic conditions limited lipid oxidation but enhanced mutton odour intensity. Nitride had a pro-oxidant effect on mutton adipose tissue stored in air. There was no corresponding effect on mutton odour intensity. These findings suggest that lipid oxidation products contribute very little to mutton odour from adipose tissue, and possibly also to species flavour differences in lean meats.

Emulsion meat products are made with little regard to rheological properties of different muscles. Here the rheology of gels made from three classes of muscle defined by myosin type (fast twitch, slow twitch and heart) are compared. Myofibrillar fractions were prepared from representative bovine muscles-cutaneus trunci, masseter and heart-by a procedure that removed connective tissue, fat and sarcoplasmic proteins. Complicating effects of nongelling agents were thus minimized. Fractions were mixed with NaCl and pyrophosphate at concentrations typical of those used in processed meats. Rigidity and elasticity of the gelling mixtures were monitored during heating from 10 to 84°C over a range of pH values. Several indices of gelation showed that masseter and heart (slow muscle group) gelations were similar to each other but distinct from cutaneus trunci (fast) gelation. Gelation temperature was 10°C lower for fast than slow, perhaps explainable by one of two hypotheses: differential salt extraction or lower thermal stability of fast myosin rod. Cutaneus trunci gels were also more rigid at all pH values. Slow group gels suffered from proteolysis, which was combated with cathepsin inhibitors. For both fast and slow groups, rigidity increased as pH decreased, analogous to results reported for purified myosin in dilute solution. Texture also changed. Below pH 5·7 slow group gels were brittle and granular, with low water-holding capacity. Above that pH, gels were elastic and smooth. The equivalent point for cutaneus trunci gels was pH 5·5. Around pH 7, pyrophosphate had a fluidizing effect at pregelation temperatures, but elasticity data indicated that this ion plays no part in final gelation.

The potential use of the thermophile enzymes E A.1 protease (from Bacillus strain E A.1), 4-1.A protease (from Thermus strain Rt4-1.A) and caldolysin (from Thermus strain T-351) in meat tenderisation has been investigated. Temperature-activity relationships illustrated that E A.1 and 4-1.A proteases were more active on collagen than on meat powder at cooking temperatures (70-90°C), whereas caldoysin was more active on meat powder. The potential of E A.1 and 4-1.A proteases was therefore investigated further using sensory and mechanical evaluation. An Instron Universal Testing Machine was used to quantitatively investigate the effect of cooking temperature and protease concentration on homogenised meat patties. With a cooking time of 30 min, the best protease concentrations (of those used) were found to be 0·75 U/g meat for E A.1 protease and 1·5 U/g meat for 4-1.A protease. The optimum cooking temperature was 80°C in both cases. Sensory analysis confirmed that these concentrations (and also 0·38 U/g meat for E A.1 protease) improved the tenderness significantly. At high concentrations the proteases had a detrimental effect on the mouthfeel of the patties. At lower concentrations this effect was less marked, and good tenderisation was obtained.

Electrical stimulation, freezing and thawing, ageing and type of packaging used during ageing are factors which could influence the final colour of meat. The experiment reported here determined the individual and additive effects of these factors in displayed lamb. Initial panel scores for colour of chops were increased by electrical stimulation and decreased by thawing and by ageing for up to six weeks. Chops from loins which had been aged in vacuum pack had higher initial scores than those aged in oxygen-permeable film. Hunter colour values for chops from stimulated carcasses were much less variable than those for chops from unstimulated carcasses. Stimulation, therefore, produced a more uniform product. Hunter L, a and b values all declined during display, the greatest decline being in a (redness). Hunter values were not good predictors of initial panel scores but Hunter a and hue (ab) both declined with panel scores. With no ageing, the display life of stimulated chilled lamb was longer than that of unstimulated lamb, but this advantage disappeared after ageing for 2 weeks in a vacuum pack. The display life of thawed unstimulated lamb was only slightly inferior to that of chilled unstimulated lamb when both were vacuum-packed, but thawed stimulated lamb resulted in a much reduced display life. Ageing of loins in oxygen-permeable film adversely affected display life of chops. Total drip loss from rigor to the end of display was significantly affected by all treatments except stimulation. The dominant cause of drip loss was the freeze-thaw treatment. In chilled and thawed lamb, ageing increased drip. Packaging had a lesser effect on drip.

Freshly prepared salted pastes (2.5%, w/w NaCl) of muscle tissue of the Antarctic fishes Pagothenia borchgrevinki (white muscle) and Dissostichus mawsoni (red and white muscle) rapidly formed cold-set gels. Set times were minutes rather than the hours required to cold-set salted pastes of fish from cold- temperate waters. Cold-setting was related to habitat temperature and the stability of fish muscle myosin, the protein responsible for gel formation.

Two trials are reported in which bulls were implanted with zeranol and slaughtered at 18 months. There was no significant change in carcass weight due to zeranol in either trial. Samples of the longissimus dorsi (LD) and splenius (Sp) were cross-cryosectioned, stained for myofibrillar ATPase and examined by conventional light microscopy. The stain resolved three fibre types: I, slow contracting with an oxidative metabolism, IIA, fast-oxidative-glycolytic and IIB, fast-glycolytic. In the LD from treated bulls, the occurrence of IIB fibres was increased, apparently at the expense of IIA fibres, as the occurrence of I fibres was unchanged. These occurrence changes parallelled previously reported effects of castration. Changes in Sp were less dramatic. In one trial IIB fibres were absent from all Sp muscles, but, in the other, some of the Sp muscles from treated animals contained these fibres whereas they were absent from the Sp of the control group. If the changes in fibre type occurrence due to zeranol extend to skeletal muscles other than LD and Sp, there is likely to be a subtle change in the musculature's metabolism. Fibre areas were largely unaffected by zeranol. In this respect zeranol did not mimic castration.

Samples of bovine muscles were cross-sectioned and stained for myofibrillar ATPase. Three fibre types were distinguished, I, IIA and IIB. In the longissimus dorsi (LD) muscles of steers the average occurrence of IIB fibres was 32%, but in bulls was only 8%. The difference was highly significant. In contrast, the average occurrence of I fibres in steers and bulls was not significantly different. IIB fibres were generally rare in splenius (Sp) muscle, and occurred in some steers but in no bulls. That IIB fibres were more common in steer muscle was confirmed by studies with pairs of identical twins. The increased occurrence of IIB fibres in steers was unrelated to carcass weight changes often associated with castration. Fibre type occurrence data in steer or bull muscles were highly variable. Also, muscles of twins remained macroscopically similar in spite of significant maleness differences between two animals of a pair. Together, these results indicate that castration exerted a relatively minor, but nonetheless significant, effect on the muscles studied. Other factors, such as breed, apparently exert greater effects: LD muscles of Sahiwal × Friesian bulls (a tropical-temperate cross) were very steer-like in composition. Areas of fibres increased with carcass weight. For LD, areas increased with similar slopes in steers and bulls, but for Sp, areas in bulls increased with steeper slopes. This difference related to the increased development of muscles about the neck in bulls. Further, in heavier bulls, areas of IIA fibres were significantly larger than areas of I fibres. Evidence is presented which suggests that the paucity of IIB fibres in bulls and the disproportionate area increases of IIA fibres in bull Sp, relate to the serum concentrations of androgens, which differ markedly in steers and bulls. Possible modes of action of androgens are discussed.

Homogenates from germinating castor bean endosperm were fractionated by sucrose density gradient centrifugation and examined for mixed function oxidase activity. Activity of cinnamic acid 4-hydroxylase and p -chloro- N -methylaniline N -demethylase was highest in the endoplasmic reticulum fraction. Activity of both enzymes is dependent on NADPH and on molecular oxygen; both activities are inhibited by carbon monoxide. When challenged with a number of potential inhibitors the enzymes responded in ways fairly typical of mixed function oxidases from other plants and animals. The N -demethylase appears to be specific for N -methylarylamines. In the absence of NADPH, cumene hydroperoxide is able to support N -demethylation. The mechanistic significance of this activity is discussed.

Recent studies using isolated muscle fibres have established a link between the histochemical fibre types, I, IIA and IIB, which can be defined by myofibrillar ATPase activity, and three forms of myosin heavy chain. This work is reviewed, as is work on metabolic variability within these fibre types. Results are them presented which show that the activity of myofibrillar ATPase in sections, although principally determined by the myosin heavy chain, is modified by other myofibrillar components, as yet unidentified. Evidence is also presented for hybrids of myosin heavy chain in muscle fibres. Finally, metabolic variability within the fibre types is examined for bovine muscle. It is concluded that, in spite of wide metabolic variability within types, a classification based on myofibrillar ATPase activity is still useful.