Influence of freezing method on thaw drip and protein loss of low-voltage electrically stimulated and non-stimulated sheeps' muscle

South African Mutton Merino wethers (n = 32) were slaughtered, yielding carcasses with a mean weight of 22·18 ± 2·11 kg. Sixteen carcasses were electrically stimulated (ES) (21 V, 60 Hz, 120 s) immediately and all carcasses were chilled at room temperature (16°C) for 3 h and then overnight at 4°C, 95% RH. Both left and right Mm. longissimus lumborum et thoracis were excised and cut into six portions (77 g ± 7·8 g), each placed separately in a polyethylene bag and randomly allocated to five freezing treatments. These were: (1) cryogenic, -65°C; (2) cryogenic, -90°C; (3) walk-in-freezer, -21°C; (4) blast freezer, -21°C; (5) domestic freezer, -25°C. The respective freezing rates were 4·4, 6·4, 0·55, 0·35 and 0·51 cm h(-1) to -2·2°C at core depth of 1 cm below the surface. Samples were frozen to core temperatures of -20°C, removed and placed in a storage freezer (-20°C) for 48 h and 2·5 months. Samples were then suspended in perforated bags in a chiller (4°C) to thaw, and drip was collected in outer bags over the periods 0-24, 24-48, 48-72 and 72-96 h and expressed as g (100 g)(-1). Freezing methods had significant (P < 0·01) influences on drip loss in both ES and NES samples. Following storage for 48 h post-freezing at -20°C, total drip (g (100 g)(-1)) over 96 h of both ES and NES samples for the five freezing treatments were respectively: (1) 7·61 and 4·61; (2) 7·35 and 3·29; (3) 9·44 and 4·68; (4) 9·07 and 5·43; (5) 10·58 and 5·15. Following storage for 2·5 months, the total ES and NES drip were respectively, (1) 11·25 and 9·38; (2) 10·36 and 9·15; (3) 13·72 and 12·65; (4) 13·70 and 12·26; (5) 11·92 and 11·29. Total protein in the drip did not differ between freezing treatments. Differences between ES and NES samples did occur in the 48 h storage group. It is concluded that cryogenic freezing results in less thaw drip than the vapour compression systems. This advantage of cryogenic freezing disappears if meat is stored for long periods at -20°C. Electrical stimulation increases the drip loss in samples frozen for 48 h, but the differences are not significant after 2·5 months frozen storage. Protein losses parallel the drip.     

Proteinase (Cathepsin B, D, L and Calpains) levels and conditioning rates in normal, electrically stimulated and high-ultimate-pH chicken muscle

Control, electrically stimulated (ES) and glycogen-depleted (GD) chicken muscles were conditioned at 15°C with continuous mechanical testing for extensibility. The ES and GD muscles went into rigor 3·6 and 2·8 h earlier, respectively, than control muscle. At 24h post-rigor the extensibility of control muscle (11·2%) was markedly less than ES (19·2%) and GD (27·3%) muscles indicating that these latter two treatments should provide more tender meat. Measurement of sarcomere lengths showed no significant differences between control and GD muscle and thus, the greater extensibility in the high pH condition may be restricted to a wider separation of myofibriller fragments at the intermittent fracture zones when under load. Examination of muscle proteinase (cathepsins B, D and L, calpains I and II) and glycosidase (β-d-glucuronidase, N-acetyl-β-d-glucosaminidase) levels at 0 and 48h post-slaughter revealed changes in some key enzymes between the different treatments. Calpain I activity declined markedly during 48h storage of ES muscle (83%) compared to control (58%) and GD (63%) muscles. Cathepsin B and L activities did not decline during storage of ES muscle but there was a slight fall in control and GD muscles. Dosing of chicken shortly before slaughter with inhibitors of cysteine proteinases had a negligible effect on conditioning rate, apparently due to lack of inhibition of these proteinases during this short time period in the intact muscle.     

Evaluation of salt, polyphosphates and their blends at different levels on physicochemical properties of buffalo meat and patties

The effects of sodium pyrophosphate (SPP), sodium tripolyphosphate (STPP), sodium hexametaphosphate (SHMP), sodium acid pyrophosphate (SAPP) and their blends at different levels (0·3, 0·5 and 0·7%), along with 2% sodium chloride on certain quality parameters of buffalo meat and patties were evaluated. The SPP, STPP and phosphate blends significantly increased pH, water-holding capacity (WHC), emulsifying capacity (EC), extractability of salt soluble proteins (SSP), colour of ground meat, decreased cooking loss (CL), improved emulsion stability (ES) and enhanced yield, texture and moisture retention of cooked patties. Compared to these phosphates, SAPP and SHMP had significantly poorer effects on improving the quality of meat and patties. The order of effectiveness of phosphates was SPP > STPP > SHMP. In general, pH, WHC, SSP, ES, yield and moisture content of patties increased progressively with increasing level of phosphate while CL decreased. Among blends containing two polyphosphates, those of 90% SPP + 10% SHMP and 75% SPP + 25% STPP were relatively more effective. A phosphate blend consisting of 65% SPP, 17·5% STPP and 17·5% SAPP was equally effective as that of SPP in improving the functionality of hot and chilled meat and had the advantage of reducing the amount of sodium by 3%.     

Factors associated with body temperature of healthy Holstein dairy cows during the first 10 days in milk

In this prospective observational study rectal and vaginal temperature of 82 (26 primiparous, 56 multiparous) early post-partum healthy dairy cows that calved without intervention within 3 months and did not show clinical signs of infectious and metabolic diseases were continuously measured and evaluated for associations with plausible factors during the first 10 days in milk (DIM). During May, June and July mean (±SD) temperature humidity index (THI) was 60·1±5; 66·8±5·6 and 74·2±4·3, respectively. Environmental conditions had a negligible effect on body temperature (BT) during May (P<0·05). During June and July, however, the ambient temperature and THI influenced BT (P<0·05). Furthermore, plausible factors like parity, DIM, months and time of day had an effect on BT (P<0·05). Overall, primiparous cows demonstrated 0·2°C greater BT during the first 10 DIM than multiparous cows. The effect of parity, however, on BT varied between DIM according to month (P<0·001). During this 3-month study period all cows demonstrated BT rhythms; however, the amplitude of BT increased from May to July (0·3 to 0·7°C). A greater proportion of the vaginal temperature measurements exceeded a threshold tested (≥39·5°C) during July (46·8%) than in June (33·9%) and May (19·3%). Overall the percentage of BT values above a threshold of ≥39·5°C was lower during the period 6.00-10.00 compared with the remaining 20 h (P<0·05). Therefore this study concluded that the BT of healthy post-partum dairy cows during the period 1-10 DIM post partum is greater compared with the reference range of 38·6 to 39·5°C reported by others and is influenced by parity, DIM, time of day and THI. When the association between BT and THI increased the reliability of threshold levels of BT (≥39·5°C) decreased.     

Ultrasonication and the quality of human milk: variation of power and time of exposure

Donor human milk is pasteurized to prevent the potential risk of the transmission of pathogens to preterm infants. Currently, Holder pasteurization (human milk held at 62·5°C for 30 min) is used in most human milk banks, but has the disadvantage that it results in excessive inactivation of important bioactive components. Power-ultrasound (20-100 kHz) is an emerging technology for the preservation of foods and could be an alternative method for the treatment of human milk. The aim of this study was to investigate the effect of different ultrasound settings on the elimination of Escherichia coli and the retention of bile salt stimulated lipase (BSSL) activity. Ultrasonication with a constant power decreased Esch. coli viability exponentially over time until the processing temperature increased to sub-pasteurization level to between 51·4 and 58·5°C, then a log10 1·3 decrease was observed (P<0·05). BSSL activity decreased to 91% until a temperature of 51·4°C and then it decreased to 8% between 51·4 and 64·9°C. Ultrasonication with a constant energy and various power and exposure times showed the highest temperature (53·7°C) when treated with the longest exposure time and lowest ultrasound-power (276 s at 3·62 W) compared with 37·6°C for 39 s at 25·64 W. The findings predict that the viability of Esch. coli could be reduced by log10 5 with a minimal loss of activity of BSSL by applying 13·8 kJ of energy in 12 ml of human milk using high ultrasound power over a short exposure time to ensure that the temperature remains below the critical level for protein denaturation. Alternatively, the use of lower power settings such as the 26 W used in the present studies would require a cooling system to ensure the human milk BSSL was protected against temperature denaturation.     

Water distribution in porcine M. longissimus dorsi in relation to sensory properties

The water distribution in M. longissimus dorsi (LD) from purebred Hampshire and Swedish Yorkshire pigs was recorded by proton-pulse-NMR. Three domains of water were seen with this type of method, designated as free, extracellular and intracellular water, respectively. The relative proton population for the free water increased from 1·8% in raw, to 3·3% in fried, samples from Hampshire and to 4·2% for the Yorkshire samples. The relaxation time of the extracellular water increased for Hampshire samples from 100 ms, when raw, to 108 ms and 114 ms for samples fried to centre temperatures of 68°C and 80°C, respectively. For Yorkshire samples it decreased from 122 to 108 and 109 ms, respectively. The relative proton population of the extracellular water decreased after frying (raw: 24·5%, 68°C: 18·6% and 80°C: 13·9%) for Hampshire samples, whereas the corresponding populations of protons for those of Yorkshire were 16·5%, 19·2% and 16·6%. The intracellular water had relaxation times of about 40 ms (raw), 30 ms (68°C) and 28 ms (80°C) for both breeds. The relative proton populations were: for Hampshire, 74·1% (raw), 77·7% (68°C), 83·4% (80°C) and, for Yorkshire, 81·6% (raw), 75·5% (68°C) and 77·2% (80°C). On average, the samples of Hampshire were more juicy and tender than those of Yorkshire. The sensory properties were related to the water distribution, but obvious influences of breed and end-point temperature at frying were noted for the relationships. In general, the juiciness and tenderness of fried LD samples could fairly well be predicted by the water distribution in raw meat. However, due to the influence of breed and temperature, different variables are best for the prediction. Also, when the sensory properties were related to the water distribution in fried samples, the influences of breed and end-point temperatures were noted.     

The effect of different levels of sunflower head pith addition on the properties of model system emulsions prepared from fresh and frozen beef

The effect of sunflower head pith on the functional properties of emulsions was studied by using a model system. Oil/water (O/W) model emulsion systems were prepared from fresh and frozen beef by the addition of the pith at five concentrations. Emulsion capacity (EC), stability (ES), viscosity (EV), colour and flow properties of the prepared model system emulsions were analyzed. The pith addition increased the EC and ES and the highest EC and ES values were reached when 5% of pith added; however, further increase in the pith concentration caused an inverse trend in these values. Fresh beef emulsions had higher EC and ES values than did frozen beef emulsions. One percent pith concentration was the critic level for the EV values of fresh beef emulsions. EV values of the emulsions reached a maximum level at 5% pith level, followed by a decrease at 7% pit level.     

Heat-induced gelation of actomyosin

Rheological properties of actomyosin gels were markedly affected by protein concentration, pH and heating temperature. Gel strength increased with increasing protein concentration (30-60 mg ml(-1)) and heating temperature (55-75°C), but decreased with increasing pH (5·5-9·0). Low heating temperatures (50-55°C) favoured the formation of more cohesive actomyosin gels than the higher heating temperatures (60-75°C). Gels formed at low pH (5·5 and 6·0) were less cohesive than those formed at high pH (7·5-9·0). Addition of ATP and pyrophosphate (10 mm) prior to heating decreased gel strength and cohesiveness, whereas EDTA (1-5 mM) reduced gel strength but did not affect gel cohesiveness.     

Modelling post-mortem tenderisation-II: Enzyme changes during storage of electrically stimulated and non-stimulated beef

Levels of calpains I and II, cathepsins B and L and β-glucuronidase were determined in extracts of electrically stimulated and control beef M. Pectoralis profundus stored at temperatures between 0 and 30°C and varied to avoid muscle shortening. The level of lysosomal enzymes remained essentially unchanged throughout storage. The levels of calpain II were largely unaffected by the early treatments and decreased slightly throughout ageing. The level of calpain I, in both stimulated and control meats, was unaffected by temperature prior to the attainment of about pH 6·2 and thereafter the loss was accelerated at higher temperatures. In the extreme case studied, that of stimulated meat held at 15°C, 73% of the activity was lost in the first 24 h. After ageing, the level was about 11% of the initial when stored at 1°C and 25% when stored at 15°C. The exponential decay constants for the decrease in the levels of calpain I were 0·01 h(-1) at 1°C and 0·06 h(-1) at 15°C, and were the same as those for the previously determined rate of tenderisation. This suggested that the rate of proteolysis by calpain I was linked to the rate of tenderisation.     

Influence of dietary fat and α-tocopherol supplementation on lipid oxidation in pork

Sixty-four pigs, approximately 3 weeks old, were fed diets containing 3% beef tallow or 3% soya oil with either a basal (10-50 mg/kg diet) or supplemented (200 mg/kg diet) level of α-tocopheral acetate. In pigs fed the soya oil diet the neutral and polar lipid fractions of muscle tissue and the total lipid fraction of adipose tissue had significantly (P < 0·05) higher C18:2/C18:1 ratios when compared to pigs fed the tallow diet. Muscle from pigs fed the soya oil diet was significantly more susceptible (P < 0·05) to lipid oxidation than muscle from pigs fed the tallow diet. In pigs receiving the α-tocopherol supplemented diet, α-tocopherol levels were approximately 3·3, 2·8 and 2-times higher in plasma, muscle and adipose tissue, respectively, when compared to pigs fed the basal level of α-tocopherol acetate. α-Tocopherol supplementation significantly increased (P < 0·05) the oxidative stability of muscle from pigs fed both the tallow and soya oil diets.     

Effect of temperature of comminution on the stability and eating quality of 'English' sausages

Sausages were prepared after equilibrating the ingredients to temperatures in the range 2° to 37°C. Following comminution for 6·5 min the temperatures of the batters ranged from 15 to 33°C and their pHs from 6·25 to 6·48. During storage at -20°C sausages prepared from the high temperature batters lost more weight than those made from batters prepared at the lower temperatures (0·3% compared to 1·2%). Increasing temperature of comminution led to increased cooking losses, softening in texture and darkening in colour. However, even at the highest temperatures complete emulsion breakdown did not occur as cooling losses were still only about 20%. Subjective assessment indicated that at least up to comminution temperatures of 25°C the sausages were acceptable. At temperatures above 30°C off-flavours developed. It is suggested that comminuted meat products can be manufactured in situations where refrigeration is not available, provided a preservation system can be devised to inhibit microbial and chemical spoilage.     

The effect of cooking temperature on the functional properties of beef proteins: The role of ionic strength, pH, and pyrophosphate

This study examined the effect of ionic strength (0·12 to 0·52), pH (5·50 and 6·00), pyrophosphate (PP) concentration (0 and 0·31%) and cooking temperature (52 to 87°C) on the cook yield (CY) and tensile strength (TS) of beef homogenates. Increasing the ionic strength, pH and pyrophosphate concentration increased the temperature at which cooking loss first occurred and decreased the temperature required for maximum TS. For most treatments, ionic strengths between 0·32 and 0·42 prevented cooking loss at all temperatures; the lower ionic strengths were required at the higher pH and PP concentration. Maximum TS occurred at 66°C for treatments that had no cooking loss between 60° and 75°C. For treatments that had cooking loss in this temperature range, TS increased linearly with increasing temperature; however, the TS values of these treatments were much lower than those in the former category. CY and TS were optimized by heating to 66°C. PP had a positive effect on both functional properties at ionic strengths >0·25 but a negative effect at ionic strengths <0·25.     

Phosphates and antioxidants as cryoprotectants in meat batters

The gelation and rheological properties of minced beef frozen and stored at -18°C for 6 months without additives, with salt (1·5% NaCl), tripolyphosphate (TPP 0·5%), sodium acid pyrophosphate (SAPP 0·5%) and an antioxidant mix (BHA + BHT, 200 ppm) were studied. The relationships between shear rate and shear stress for the different treatments were nonlinear and resembled the Bingham pseudoplastic behaviour. Continuous evaluation of the modulus of rigidity (G) during cooking (0·5°C/min) revealed higher G values for the unfrozen phosphate treatments. Salt addition resulted in significantly lower G values of the stored meat compared to the control. Antioxidant addition retarded some of these effects. Among the phosphates, TPP was the best in maintaining the same G values as the control. Water-holding capacity (after salt addition) was increased after phosphate addition in the unfrozen meat and did not change after storage. The control, NaCl and antioxidant treatments showed an increase in WHC during storage.     

Influence of temperature on the emission of di-(2-ethylhexyl)phthalate (DEHP) from PVC flooring in the emission cell FLEC

Emissions of di-(2-ethylhexyl) phthalate (DEHP) from one type of polyvinylchloride (PVC) flooring with approximately 13% (w/w) DEHP as plasticizer were measured in the Field and Laboratory Emission Cell (FLEC). The gas-phase concentrations of DEHP versus time were measured at air flow rate of 450 mL·min(-1) and five different temperatures: 23 °C, 35 °C, 47 °C, 55 °C, and 61 °C. The experiments were terminated two weeks to three months after steady-state was reached and the interior surface of the FLECs was rinsed with methanol to determine the surface concentration of DEHP. The most important findings are (1) DEHP steady-state concentrations increased greatly with increasing temperature (0.9 ± 0.1 μg·m(-3), 10 ± 1 μg·m(-3), 38 ± 1 μg·m(-3), 91 ± 4 μg·m(-3), and 198 ± 5 μg·m(-3), respectively), (2) adsorption to the chamber walls decreased greatly with increasing temperature (measured partition coefficient between FLEC air and interior surface are: 640 ± 146 m, 97 ± 20 m, 21 ± 5 m, 11 ± 2 m, and 2 ± 1 m, respectively), (3) gas-phase DEHP concentration in equilibrium with the vinyl flooring surface is close to the vapor pressure of pure DEHP, and (4) with an increase of temperature in a home from 23 to 35 °C, the amount of DEHP in the gas- and particle-phase combined is predicted to increase almost 10-fold. The amount in the gas-phase increases by a factor of 24 with a corresponding decrease in the amount on the airborne particles.     

Physical and sensory attributes of hot-processed and conventionally chilled hams and bellies from electrically stimulated and non-stimulated pork carcasses

Forty-eight fresh hams and bellies were obtained from 24 market weight hogs (x = 94·5 kg) of which twelve were electrically stimulated (ES) by pulsing current immediately after exsanguination. The left side of each non-stimulated (NS) carcas was fabricated after conditioning for 3h post mortem at 17°C (NS hot-processed). The left sides of ES carcasses were fabricated 1 h pm. The right sides were fabricated following a 24 h cooler chill at 2°C (conventionally chilled: CP). Hams from ESCP carcasses had higher (P < 0·05) smokehouse yields than hams from NS carcasses. Hams that were hot-processed had higher smokehouse yields than the NSCP hams. Time of fabrication (1, 3 or 24h post mortem) did not affect smokehouse yields. Conventionally chilled bellies obtained from ES carcasses showed higher (P < 0·05) residual nitrite levels than those front electrically stimulated hot-processed (ESHP) carcasses. No differences were found for residual nitrite levels in the non-electrically stimulated sides. Panelists were unable to detect any sensory differences from the bacon strips. Sensory scores of ham slices were more juicy for non-stimulated hot-processed carcasses (NSHP) than those from ESHP carcasses. Panelists found the ham slices from NSCP carcasses to be more tender (P < 0·05) than those from electrically stimulated cold-processed (ESCP) carcasses. Results from this study clearly indicated that hot-processing of pork can provide hams and bellies that are acceptable for the production of cured hams and bacon of comparable quality and yield to those currently being produced under conventional processing methods.     

The influence of high temperature, type of muscle and electrical stimulation on the course of rigor, ageing and tenderness of beef muscles

The course of rigor mortis (rigor), ageing and tenderness has been evaluated for three beef muscles; M. biceps femoris (BF), M. semimembranosus (SM) and M. semitendinosus (ST), when entering rigor at constant temperatures of 15 and 37°C respectively, with and without electrical stimulation (ES/NS) (85 V, 14 Hz and 32 s). The course of post-mortem changes has been registered by isometric tension, by shortening of unrestrained muscle strips and by following the pH decline and the changes in metabolites, such as ATP and CP. Ageing at +4°C was recorded by measuring Warner-Bratzler (W-B) shear values 2, 8 and 15 days post mortem. On the last occasion, the sensory properties of the cooked meat were also evaluated. Maximum shortening and isometric tension were higher at 37°C as compared to 15°C, whereas ES did not reduce rigor shortening. A high correlation between maximum shortening and the ATP-level at the onset of the shortening rapid phase was found (r = 0·77(???)), which could explain the greater shortening obtained at 37°C compared to 15°C. Rigor shortening is an important phenomenon governing meat tenderness as tenderness is highly affected by rigor temperature but not by ES. This was the case for muscles SM and ST but not for BF muscle. Even though tenderness was measured after ageing (15 days post mortem), shortening during rigor seems to be more important for toughness when rigor mortis occurs at 37°C than any suggested tenderizing effect due to increased proteolysis in this temperature region.     

Kinetic studies of the effect of muscle fiber type and tripolyphosphate on the aggregation of porcine salt-soluble proteins

The kinetics of thermal aggregation of salt-soluble proteins (SSP) isolated from porcine Longissimus dorsi (75% white fiber, Serratus ventralis (43% red fiber, and Vastus intermedius (76% red fiber) muscles were studied in the presence of sodium tripolyphosphate (TPP). SSP solutions containing 0-2·0% TPP were heated at constant temperatures between 40° and 70°C, and protein aggregation was monitored using turbidity measurements. SSP aggregation followed first-order kinetics, and the rate and extent of aggregation increased with the red fiber content. Addition of TPP generally increased the aggregation temperature for both white and red muscle SSP, but the changes in the aggregation rate varied depending on the specific temperature and muscle type. Arrhenius plots revealed 10·2-11·5% reduction in the activation energy for SSP aggregation caused by 0·5% TPP. These results indicate that SSPs from red and white muscle types differ in thermal properties and response to phosphate treatments.     

pH and Sodium Chloride Effects on Emulsifying Properties of Egg Yolk Phosvitin

The emulsifying properties of phosvitin dissolved in water and 0.1, 0.5 and 1.0 M NaCl were determined from pH 3 to 10. The change in its emulsifying activity (EA) with pH was slight but significant (p<0.05) and emulsion stability (ES) was relatively high (68-73%), except at pH 5 (17%) and 10 (48%). The EA of phosvitin was higher than that of bovine serum albumin (BSA) at pH 3 or 8 and ES was higher than BSA at all pH levels except at pH 5 and 10. Added NaCl decreased in the EA of phosvitin at pH 3 and 10 and decreased the ES between pH 3 and 9. Increased instability of emulsions resulted mainly in coalescence of oil droplets at NaCl ≥ 0.5M. Salt increased the viscosity of phosvitin emulsion only at pH 3 but not at pH > 5. The viscosities of BSA emulsions were higher than those of phosvitin at pH 3, 5 or 8.     

Chilling pig carcasses: Effects on temperature, weight loss and ultimate meat quality

Effects of conventional (4°C, air velocity 0·5 m/s) and forced chilling at -5°C (120 min) or -30°C (30 min) with air velocities of 1, 2 or 4 m/s, followed by conventional chilling till 24 h post mortem on temperatures, meat quality and weight losses, were studied. Experiments were carried out in six batches of six slaughter pigs each (crossbred gilts, weighing 105-110 kg. The subcutaneous temperature decreased very rapidly to values below 0°C when 'ultra' rapid chilling (-30°C) at high air velocities (4 m/s was used. Immediately after rapid chilling, when the carcasses were railed into a conventional chiller, the subcutaneous temperature increased above the air temperature, after which the decline in temperature was continued. Temperature inside the biceps femoris muscle decreased from the start of chilling rather slowly according to an asymptotic curve until ultimate values of 4°C were reached. Theoretically calculated temperatures during slaughter and chilling were comparable with the measured values; indicating that a finite-element calculation method in combination with a cylindrical model for heat transport can be used to predict muscle temperatures for various chilling regimes. Losses in carcass weight, 24 h after conventional and forced chilling at -5°C, were about 2%. After 'ultra' rapid chilling (-30°C) the losses were reduced to 1·3% when air velocity was increased to 4 m/s. Meat quality of the longissimus lumborum muscle was not significantly affected by the various chilling regimes except for the variables related to tenderness. The Warner-Bratzler shear forces were higher (P < 0·05) together with shorter sarcomere lengths (P < 0·10) after 'ultra' rapid chilling at a high (4 m/s) air velocity, indicating an increased risk of cold shortening.     

The effect of preheated tendon as a lean meat replacement on the properties of fine emulsion sausages

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.