A modified hot processing strategy for beef: reduced electrical energy consumption in carcass chilling

A beef processing strategy for improving energy and labour efficiencies, modified hot processing (MHP), was developed in a research abattoir. The work reported herein investigated carcass chilling rates and electrical energy usage in the chilling of carcasses that were processed using this approach. The MHP procedure removes the lower value cuts from the dressed carcass along with associated bone and fat. The remaining high value meat (posterior carcass quarter) is chilled in the usual manner, while the low value cuts are immediately processed (e.g. reduced into pre-blended, salted, chilled meat for emulsion-type products; rendered; directly processed as fresh, hot-boned meat, etc.). Carcasses prepared by the MHP method were dissected to quantify the amounts of lean meat, separable fat and bone removed in the procedure. These data were used with a simple model to predict the amount of chilling energy that could be saved by applying MHP prior to chilling. Electrical power to operate a blast chilling facility containing carcasses that had been processed either by conventional processing or by MHP methods was monitored and recorded, and the resulting data was used to confirm the model result. The MHP procedure reduced the refrigeration load for beef chilling by as much as 51% (P < 0·05). The amount of chilling energy to be saved would depend upon the methods employed to further process the low value tissues, and was calculated to be no less than 7%. The time for the reduced MHP carcass quarters to chill to 10°C at the fat-muscle interface of the longissimus dorsi muscle (12/13 rib) was shorter for MHP carcasses than for conventional carcasses (5·77 h vs 7·08 h, respectively) (P < 0·05). However, the times to chill the deep hip location of MHP hind quarters and conventional beef sides were not significantly different (P < 0·05).     

A modified hot processing strategy for beef: functionality of electrically-stimulated and hot-boned meat preblended with different NaCl concentrations

Chucks from 20 electrically-stimulated hot-boned (HB) and cold-boned (CB) beef carcasses were preblended with different concentrations of NaCl (0, 0·5, 1·0, 1·5 and 2·0% w/w). Preblends were analysed for pH, 2-thiobarbituric acid (TBA) values, protein extraction and emulsifying capacities. Bologna (with and without added sodium tripolyphosphate) and ground meat patties prepared from these preblends were also evaluated for cooking yield, color and texture parameters. Ultimate pH values of HB preblends increased with increasing NaCl concentration. At 1% NaCl, HB had higher ultimate pH than CB preblends (P ≤ 0·05) but preblending HB meat with 2% NaCl reduced TBA values (P ≤ 0·05) because the pH was maintained above 6·0. Higher amounts of protein were extracted from HB than from CB preblends (P ≤ 0·01), but boning and salting treatments did not affect their emulsifying capacities (P > 0·05). Two percent NaCl was required to fully achieve the prerigor salting effect. At this concentration, cooking yields of bologna prepared from HB preblends and phosphate containing bologna prepared from CB preblends were not different (P > 0·05) and were higher than those of bologna without added phosphate made from CB preblends (P ≤ 0·05). No meaningful effects were observed on color and texture parameters. Cooking losses were lower in patties made from HB than CB preblends (P ≤ 0·05) independent of NaCl concentration, but boning and salting treatments had no further effects on color or textural parameters (P > 0·05). Therefore, the superior functional properties of electrically stimulated prerigor meat can be maintained by the addition of 2% NaCl up to 2 h post-mortem.     

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%.     

Chemical composition and quality attributes of goat meat and lamb

Chemically, goat meat had significantly (P < 0·05) less intramuscular fat and significantly (P < 0·001) more moisture than lamb. The sarcoplasmic protein concentration of the goat meat was significantly (P < 0·001) greater than that of lamb while the myofibrillar protein concentration was similar in the two species.

Goat meat was darker red in colour than lamb. It had significantly (P < 0·001) superior water-holding capacity and less cooking losses than lamb. Meat flavour was significantly (P < 0·05) less strong in goat meat than in lamb.     

Effect of NaCl, polydextrose, and storage conditions on the functional characteristics and microbial quality of pre- and post-rigor salted beef

The functionality and microbial storage life of pre-rigor beef mince stored at −1.5 °C under vacuum or a saturated carbon dioxide atmosphere, or at −18 °C in polyethylene bags, was investigated. Salt (2% w/w) or salt plus the cryoprotectant Polydextrose^® (2%/2.6% w/w) was added pre-rigor to some samples. Chilled storage decreased salt soluble protein (SSP) by 13–18% (P < 0.01); frozen storage decreased SSP content by 20%. Pre-rigor salted mince in saturated carbon dioxide packs had a satisfactory microbial quality after 12 weeks storage. The cook yield of finely comminuted sausage batters made from that mince and from fresh pre-rigor mince were similar, although batter stress and strain decreased with chilled storage. Adding Polydextrose^® to salted mince improved batter strain compared with the non-additive and salt-only samples and improved batter stress compared with the salt-only samples. The microbial storage life of chilled vacuumpacked unsalted mince was less than 6 weeks; pre-rigor salting increased its storage life.     

The effect of post-mortem ageing and heating on water retention in bovine muscles

The muscles semitendinosus (ST) and psoas major (PM) were removed from chilled young bull carcasses 24 h after slaughter and stored at 4 °C. At the 1st, 6th and 12th day of post-mortem ageing the chemical composition (moisture, fat, protein, collagen) and contents of free, immobilized and unfreezable water in the muscles were estimated. The muscle steaks were boiled at 100 °C, roasted at 170 °C or fried at 160 °C to an internal temperature of 75 °C, and the amounts of total, free, immobilized, and unfreezable water in heated muscles were evaluated. The unfreezable water was estimated by DSC. In the raw muscles immobilized water constituted 74–75%, free water 16.6–17.6% and unfreezable water 7–8% of the total water. Independent of time of ageing, PM muscle contained significantly more free water than ST muscle. During post-mortem ageing, changes in free, immobilized and unfreezable water in muscles were not significant. The level of free water was highest in boiled and least in fried meat, however the amount of immobilized water was highest in fried and lowest in boiled meat. The amount of unfreezable water in muscles heated after 12 days of post-mortem ageing decreased.     

Evaluation of the antioxidant potential of grape seed and bearberry extracts in raw and cooked pork

The effect of grape seed extract (GSE) and bearberry (BB), on lipid oxidation (TBARS, mg malondialdehyde (MDA)/kg muscle), colour (CIE ‘a’ redness value), pH, microbial status (log₁₀CFU colony forming units/g pork) and sensorial properties of cooked pork patties was investigated. GSE (0–1000 μg/g muscle) and BB (0–1000 μg/g muscle) were added to raw pork (M. longissimus dorsi) patties which were stored in modified atmosphere packs (MAP) (75% O₂:25% CO₂) for up to 12 days at 4 °C. Cooked pork patties were stored in MAP (70% N₂:30% CO₂) for up to 4 days at 4 °C. Mesophilic plate counts and pork pH were unaffected by GSE and BB. GSE and BB addition decreased (P < 0.05) lipid oxidation (TBARS) in raw pork patties on days 9 and 12 of storage, relative to controls. Antioxidant activity of GSE and BB was observed in cooked pork patties demonstrating the thermal stability of GSE and BB. The ‘a’ redness values of raw and cooked pork patties marginally increased with increasing GSE concentration. The sensory properties of cooked pork patties were unaffected by GSE and BB addition. Results obtained demonstrate the potential for using health promoting nutraceuticals in meat and meat products.     

Variation in haem pigment concentration and colour in meat from British pigs

Variation in chemically determined total haem pigment concentration and instrumentally determined colour was examined in 223 samples of M. longissimus dorsi (LD) representative of the majority of slaughter pigs currently produced in the UK. Whether pigs were sired by White (Large White or Landrace) or Meat-line boars did not affect any measured characteristic but source breeding company influenced total haem pigment concentration (P < 0·01). Haem pigment concentration was higher in muscles from gilts, compared with castrates, boars being intermediate. Gilts also had darker muscles, based on EEL Reflectance values (P < 0·05), and lower hue values (P < 0·05). When compared with animals fed ad-libitum, restricted-fed pigs had higher concentrations of muscle haem pigment (P < 0·001) and this resulted in meat that was slightly darker (P < 0·05), despite having lower ultimate pH (pHu) (P < 0·05), and had a lower hue value (P < 0·001). Measurements of reflectance, total soluble protein and pHu indicated that differences in the incidence of potentially pale, soft, exudative or dark, firm, dry muscle were unlikely to be important contributors to variation in the colour of the meat in this study.     

The effects of antifreeze proteins on chilled and frozen meat

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.     

Carcass and meat quality of finishing Friesian steers fed the β-adrenergic agonist L-644,969

The effect of the β-adrenergic agonist L-644,969 on selected parameters of carcass and meat quality was examined in Friesian steers. Four groups of 18 steers were individually offered ad libitum a pelleted diet that contained 0, 0·25, 1·0, or 4·0 ppm L-644,969 for 12 weeks prior to slaughter. L-644,969 quadratically increased carcass weight (3·7, 9·3, and 8·5%, P < 0·001) and altered the distribution of lean meat such that a greater (0·3–5%; P < 0·01) proportion was in the more valuable cuts. There were no effects of L-644,969 on carcass-chill loss and on the water-holding capacity of the longissimus thoracis et lumborum (LTL) muscle. The intramuscular-fat concentration of the LTL was decreased (27–50%; P < 0·01) and the effects on muscle ultimate pH were small and commercially unimportant. Fibre-optic-probe measurements of the LTL indicated darker (P < 0·01) meat due to β-agonist treatment. L-644,969 increased the shear force required to cut through cooked muscle from the LTL (159%, 209%, and 217%, P < 0·001). It is concluded that L-644,969 treatment improved the quantity and distribution of lean in the carcass but impaired meat quality, primarily through a reduction in tenderness.     

Secondary sexual development (Masculinity) of bovine males: 1. Influence on carcass composition, cutability, economic value and certain muscles

Differences in carcass composition, cutability, economic value of the carcass and distribution of certain muscle groups, between bulls with secondary sexual characteristics (bulls(+)), those without (bulls(−)), and steers were investigated. Two carcass mass groups (250–300 and 301–350 kg) were compared. Five carcasses of either mass group were studied within each sex condition group. Bulls(+) had a higher meat percentage (P < 0·05) than bulls(−) or steers. They also had a lower bone percentage than steers (P < 0·05), but non-significant differences were found between bulls(+) and bulls(−) for bone percentage. Significant differences (P < 0·05) between sex condition groups were found for percentages of hindquarter, as well as for distribution of high-priced cuts. Steers had the most favourable distribution and bulls(+) the least favourable. Bulls(−) were intermediate.

Masculinity significantly (P < 0·05) influenced the distribution of the chuck, neck, brisket and hind shin cuts, whilst mass had a significant effect on the percentage hind shin and percentage thin flank. It was found that the M. rhomboideus was the only muscle of those studied that was significantly affected by masculinity and it was concluded that this muscle could be used as an indicator of the masculinity of the carcass.

The economic values of the carcasses of steers, bulls without secondary sexual development and bulls with secondary sexual development differed non-significantly.     

The chilled storage life and retail display performance of vacuum and carbon dioxide packed hot deboned beef striploins

Two cooling regimes that complied with the New Zealand meat hygiene requirement that hot deboned meat be chilled to +7 °C or less within 24 hr of leaving the slaughter floor were evaluated for the production of chilled table meats. Electrically stimulated hot deboned bull beef half striploins were either vacuum or carbon dioxide packed before being cooled in accordance with either Regime 1 (cool at +5 °C for 24 hr, transfer to chiller operating at −1.0 ± 0.5 °C) or Regime 2 (cool at +5 °C for 24 hr, hold at 5 °C for 6 days, transfer to chiller operating at −1.0 ± 0.5 °C). Striploins were removed from −1.0 °C storage 8, 28, 42, 56, 70, 84 and 98 days after slaughter and subjected to microbiological, tenderness, sensory and retail display performance evaluations.

Both Regimes 1 and 2 produced meat of acceptable mean tenderness, 8 kgF (MIRINZ Tenderometer) in either vacuum or carbon dioxide packs within 28 and 8 days of slaughter, respectively. However, 70 days after slaughter the first signs of over-ageing became apparent. Steaks from Regimes 1 and 2 maintained acceptable visual appearance during retail display at 5 °C for 48 hr and 24 hr, respectively. After these times, the product was judged by the panel to be unacceptable because of its dull dark lean tissue and grey to green discoloration of the fat. Poor colour stability during retail display was mirrored by deterioration of sensory attributes, particularly aroma which is indicative of incipient spoilage. While carbon dioxide packaging in combination with Regime 1 offered an initial microbiological advantage over vacuum packaging, this advantage was not, however, carried over into retail display.

Poor colour and sensory stability during retail display suggest that chilled table cuts derived from hot deboned bull beef are more suited to the Hotel-Restaurant-Institutional (HRI) trade than supermarket retailing. To serve the HRI, vacuum packed hot deboned bull beef primal cuts processed by Regime 1 appear to be the combination of choice. This combination would enable commercial processors to produce quality table beef with a chilled storage life of up to 70 days.     

Temperature shows greater impact on bovine Longissimus dorsi muscle glycogen debranching enzyme activity than does salt concentration

The degradation of glycogen progresses by the co-operation of two enzymes: glycogen phosphorylase (phosphorylase) and glycogen debranching enzyme (GDE). We studied the effect of temperature (4–42 °C) and salt concentration (0–3% NaCl) on bovine M. longissimus dorsi GDE activity. GDE activity (n = 4) decreased significantly with decreasing temperature from about 40–4 °C. GDE exhibited 52% activity at 25 °C and 11% at 4 °C compared to its optimum activity measured at 39 °C. In rapidly chilled meat, the reduction in GDE activity may substantially delay the rate of glycolysis. However, residual GDE activity at 4 °C seems sufficient to enable the attainment of normal ultimate pH if the available time is long enough. An increase in salt concentration from 0% to 2% and to 3% induced a significant (P < 0.001) increase in the ultimate pH of ground bovine meat (n = 6), but showed no effect on GDE activity.     

Effect of cooling rate upon processing characteristics of pork meat of different glycolysis type during post mortem ageing

Rapid chilling was applied to porcine longissimus dorsi muscles at 1 h post mortem in order to observe its effect on the quality of canned products prepared from those of different pH₁ values.

The muscle from one side of each animal was removed from the carcase 50 minutes post mortem and divided into two longitudinal strips. One was chilled immediately to 13–15°C (1 h post mortem): the other after a further hour (2 h post mortem) acted as control. After the centre temperature had reached 10°C the muscles were stored in a refrigerator at 3–5°C.

Compared with the control samples (chilled at 2 h p.m.), rapid chilling from 1 h p.m. caused an improvement in the water-holding capacity and the texture of pork meat, which had higher pH₁ values and was processed at 2, 4 and 48 h p.m. There was minimum brine retention and texture score if samples—both rapidly chilled and control—were processed at 24 h p.m.

Although brine retention of PSE pork meat could not be increased even by rapid chilling, the texture of heat treated PSE pork showed an improvement during storage, which was more pronounced after ageing for 48 h, if PSE samples were chilled at 1 h p.m.     

Secondary sexual development (Masculinity) of bovine males: 2. Influence on certain meat quality characteristics

Differences in meat quality traits between bulls with secondary sexual development (bulls(+), n = 10), those without this development (bulls(−), n = 10) and steers (n = 10) were investigated. All animals had no permanent incisors (A-age group). Significant differences (P < 0·05) between bulls(+) and bulls(−) were found for the cooking loss percentage of the M. splenius (27·83% versus 31·11%, respectively), iron content of the M. splenius (56·02μg/g versus 49·43μg/g, respectively) and total collagen content of the M. splenius (3·74 versus 4·73 measured as Hyp N/Tot N x 1000, respectively). Drip loss of the wingrib cut (4·01% versus 5·18%, respectively) was also significantly different between bulls(+) and bulls(−). For the M. longissimus thoracis, no significant (P < 0·05) differences in any of the quality-indicating parameters investigated could be found. It is concluded that the M. splenius can be used as an indicator muscle for masculinity, based on meat quality attributes. This is supported by the correlation coefficients obtained between masculinity and the intramuscular collagen content of the M. splenius (r = −0·55) and the iron content of the M. splenius (r = 0·46). For all the other quality attributes investigated, non-significant (P > 0·05) differences between the three sex condition groups were found. It is concluded that the influence of masculinity on meat quality traits of young bulls is of little practical importance in a classification and grading system.     

The effect of post-exsanguination infusion on the composition, exudation, color and post-mortem metabolic changes in lamb

Twenty-four lamb carcasses were assigned to three treatment groups: (1) control (Ctr), (2) infused with 10% (vol/wt) of a tenderizing blend (NCa), and (3) NCa plus 0·015 CaCl₂ (WCa). Results indicated that the infused carcass solution was retained in the following order: shoulder > lion > leg. Infusion had no effect (P > 0·05) on drip and cooking losses in refrigerated samples. Samples frozen and then thawed from infused carcasses had greater thaw drip (P < 0·05) and cooking losses (P < 0·01) than control samples. The amounts of drip and cooking losses were in the order: WCa > NCa > Ctr. Frozen storage preserved the red color but lowered the lightness and yellowness of ovine muscles; the opposite effect was observed following refrigerated storage. Infused samples were lighter and yellower than control in both fresh and frozen samples (P < 0·01). WCa had less red color (P < 0·01) than NCa and Ctr at all times and storage conditions. Infusion lowered (P < 0·05) the temperature of carcasses over the first 3 h postmortem (pm) compared with Ctr. The rate of glycolysis was higher in infraspinatus (IS) than in longissimus thoracis et lumborum muscle (LTL or longissimus). In both IS and LTL, glycolysis was completed within the first 6 h postmortem in NCa, whereas in Ctr and WCa, it took 12–24 h for glycolysis to be completed. The rate of glycolysis was in the order: NCa > WCa > Ctr.     

Studies on processing and refrigerated storage of 'Rista'

Effects of mutton fat levels, hot-boned versus cold-boned meat and manual versus machine mincing were studied on the quality of ‘Rista’—a popular emulsion type ground meat product of Kashmir (India). Incorporation of lamb fat at 20% level was found optimum for processing Rista. Both pre-rigor and chilled (post-rigor) meat were utilised for product manufacture. Addition of 0·5% sodium tripolyphosphate improved product binding, texture and yield. All these effects were more pronounced in machine minced Rista samples processed from cold-boned lamb meat, as compared with hot-processed and hand minced product. Cooked Rista was stored in low density polyethylene bags (0·25 μm thickness) at 4 ± 1°C in satifactory condition for 4 days.     

Characteristics of pork products from swine fed a high monounsaturated fat diet: Part 2-Uncured processed products

The effects of incorporation of 12% high-oleic sunflower (HOSO; >85% in oleic acid) into a swine diet on properties of uncured, processed pork products were determined. Restructured pork chops (with an initial total-fat level of <5%) and ground pork patties (with targeted initial total-fat levels of 15% and 30%) processed from animals fed the HOSO diet, when compared to the corresponding products from animals fed the control diet without HOSO, were 28% and 38%, respectively, lower (0·72 and 0·62 fold, respectively) in the proportion of total saturated fatty acids; 25% higher (1·25 fold) in the proportion of total monounsaturated fatty acids for both products; and 73% and 105%, respectively, higher in the ratio of monounsaturated to saturated fatty acids (M/S). The M/S ratio differences were not significantly changed by cooking. Cooking loss for either restructured chops or ground pork patties was similar between the product from animals on the control diet and that from animals on the HOSO diet. When restructured chops were evaluated for sensory properties, HOSO and control samples were similar in all sensory attributes evaluated for broiled chops while HOSO samples were juicier for precooked-reheated chops. Thiobarbituric acid (TBA) values were not significantly different between HOSO and control samples for stored, restructured chops; for pork patties, differences between the diet treatment groups were dependent on whether patties were stored raw or cooked.     

Indigenous legume fermentation: Effect on some antinutrients and in-vitro digestibility of starch and protein

Indigenous fermentation of coarsely ground dehulled black-gram dhal slurry at 25, 30, and 35°C for 12 and 18 h reduced the levels of phytic acid and polyphenols significantly (P < 0·05). The unfermented legume batter had high amounts of phytic acid (1000 mg/100 g) and polyphenols (998 mg/100 g), and these were reduced to almost half in the product fermented at 35°C for 18 h. In-vitro digestibility of starch and protein improved significantly (P < 0·05) with increase in the temperature and period of fermentation. A significant (P < 0·01) and negative correlation found between the in-vitro digestibility and the anti-nutrient further strengthens these findings.     

Quality attributes of major porcine muscles: A comparison with the Longissimus Lumborum

Quality attributes of the longissimus lumborum (LL) were compared to the attributes of the muscles semimembranosus (SM), rectus femoris (RF), biceps femoris (BF), gluteus medius (GM) and the lateral portion of the semitendinosus (ST) in the ham, the psoas major (PM) in the loin and the supraspinatus (SS), infraspinatus (IS) and triceps brachii (TB) in the shoulder. Carcasses were allocated to quality groups based on measurements of muscle exudate and lightness (CIE-L^*) in the LL. The SM, BF, GM and ST in the ham were similar to the LL (P > 0·05) in meat ultimate pH (pHu) and exudate and the GM, ST and LL were similar (P > 0·05) to the LL in lightness. The TB, RF, SS, PM and IS were similar (P > 0·05) in exudate, lightness and pHu and compared to the LL, were less exudative (P < 0·05) and darker (P < 0·05). When the LL was classed pale, and exudative, the GM, BF, SM and ST were also pale and exudative but the other muscles were darker and non-exudative. When the LL was classed dark and non-exudative, all other muscles were dark, non-exudative and the pHu was high. Therefore, the LL could serve as a reliable indicator of colour and exudate for all porcine musculature when the condition was dark and non-exudative (i.e. DFD). However, when the condition was pale and exudative (i.e. PSE), then the LL would serve as a reliable indicator only for the four major ham muscles, excluding the RF.