Reduced Drip Loss Research Articles

Edible coatings to improve storability and enhance nutritional value of fresh and frozen strawberries (Fragaria × ananassa) and raspberries (Rubus ideaus)

Abstract Chitosan-based edible coatings were used to extend the shelf-life and enhance the nutritional value of strawberries ( Fragaria × ananassa ) and red raspberries ( Rubus ideaus ) stored at either 2 °C and 88% relative humidity (RH) for 3 weeks or −23 °C up to 6 months. Three chitosan-based coatings (chitosan, chitosan containing 5% Gluconal ® CAL, and chitosan containing 0.2% dl -α-tocopheryl acetate) were studied. Results indicated that adding high concentrations of calcium or Vitamin E into chitosan-based coatings did not alter their anti-fungal and moisture barrier functions. The coatings significantly decreased decay incidence and weight loss, and delayed the change in color, pH and titratable acidity of strawberries and red raspberries during cold storage. Coatings also reduced drip loss and helped maintain textural quality of frozen strawberries after thawing. In addition, chitosan-based coatings containing calcium or Vitamin E significantly increased the content of these nutrients in both fresh and frozen fruits. One hundred grams of coated fruits contained about 34–59 mg of calcium, or 1.7–7.7 mg of Vitamin E depending on the type of fruit and the time of storage, while uncoated fruits contained only 19–21 mg of calcium or 0.25–1.15 mg of Vitamin E.

Rinse Treatment and Oxygen Barrier Properties of Films for Improving Quality Retention in Vacuum‐Skin Packaged Fresh Chicken

ABSTRACTFresh chicken drumsticks rinsed with water or salt solution (28% NaCl) were vacuum‐skin packaged in films differing in oxygen transmission rate (OTR) (< 10, 3000, ≥ 7000 cm3/m2/24 h). Salt rinsing decreased surface lightness (CIE L*). Higher OTR films maintained surface redness (CIE a*) better than oxygen barrier film. Neither rinse nor film OTR had any effect on yellowness (CIE b*). Salt rinsing drumsticks also reduced drip loss. Counts of aerobic and coliform bacteria increased during storage for product in all films. Within each film, salt‐rinsed drumsticks had lower counts at 3 and 6 d of storage (through 12 d) for total aerobic and coliform bacteria, respectively. Product in low OTR (barrier) film generally had lower bacteria counts than product in higher OTR films.

Supplementary ?-tocopherol acetate in full-fat rapeseed-based diets for pigs: effect on performance, plasma enzymes and meat drip loss

Twenty-four Large White × Landrace pigs were individually fed, from 50 to 90 kg live weight, either a control (CONT) diet containing palm oil or one of three diets based on full-fat rapeseed (250 g kg−1) (diets RD). The RD diets were supplemented with 0, 200 or 500 mg DL-α-tocopherol acetate (ATA) kg−1 diet (diets RD0, RD200 and RD500 respectively). Diets were formulated to be isonitrogenous and isocaloric. Daily live weight gain was significantly increased (p < 0.01) in pigs fed diet RD500. Plasma AT concentration was significantly increased by dietary supplementation with 200 mg ATA kg−1 but showed no further significant increase by supplementation with 500 mg ATA kg−1. At slaughter, after 45 days, carcass weights were increased for the RD500 group but dressing percentage was unaffected. ATA supplementation significantly reduced drip loss on days 4 and 5–7 in fresh muscle and on days 1 and 4 in frozen muscle. The concentrations of calcium, sodium and potassium in drip loss fluid collected on days 1 and 4 from fresh muscle were not significantly affected by treatment or by time of collection and did not suggest any change in the relative contribution of intra- and extracellular fluid to total drip loss. Plasma enzyme activities related to tissue damage (creatine kinase, alanine aminotransferase, aspartate aminotransferase and lactate dehydrogenase) were not influenced by dietary treatments. © 2000 Society of Chemical Industry

The influence of dietary magnesium supplement type, and supplementation dose and duration, on pork quality and the incidence of PSE pork

Ninety crossbred (Large White × Landrace) female pigs were used to compare the effects on ultimate pork quality of different magnesium (Mg) compounds [magnesium aspartate (MgAsp) and magnesium sulfate (MgSO4)], Mg dose (1.6 and 3.2 g elemental Mg), and Mg supplementation period (2 and 5 days) in pigs subjected to an acute stressor pre-slaughter. Pigs fed the Mg-supplemented diets had lower muscle lactic acid concentrations at 24 h post-slaughter than pigs fed the control diet. There were no significant differences in muscle glycogen concentrations in the Longissimus thoracis (LT) at 5 min, 40 min, or 24 h post-slaughter between the control and Mg-supplemented diets. Pigs fed the Mg-supplemented diets produced less pale colour pork (i.e. darker colour) and had reduced drip loss and reduced incidence of pale, soft, exudative (PSE) pork in the LT muscle compared with pigs fed the control diet. Within the Mg diets, pigs fed the MgAsp-supplemented diet produced less pale LT muscle colour than pigs fed the MgSO4-supplemented diet. There were no significant differences in LT pork quality parameters (colour and percent drip loss) regardless of whether the high or low Mg dose or the 2- or 5-day supplementation period was used. This experiment has shown that the use of dietary MgAsp supplementation at a dose of 1.6 g elemental Mg (20 g MgAsp) for 2 days prior to slaughter significantly improved pork quality and reduced the incidence of PSE pork.

Effects of pasture fertiliser N level on herbage composition, animal performance and on carcass and meat quality traits

The objectives were to examine the effects of (1) reducing fertiliser N level on grassland, (2) eliminating silage making and (3) variation in slaughter weight on performance, carcass and meat quality traits of beef cattle. A 2(fertiliser N levels)×2(winter feeds)×2(slaughter weights) factorial experiment used 48 spring-born Charolais x Friesian steers. The two fertiliser N levels were designated normal (227 (year one) and 204 (year two) kg/ha) and low (57 kg/ha) and were applied over two consecutive grazing seasons. The two winter feeds were unwilted grass silage and crop by-products (barley straw+sugar beet pulp). These were offered during the intervening winter. The silage and straw were offered ad libitum and the level of beet pulp was adjusted to give similar growth rates on the two treatments. The two slaughter weights were light (640 kg) and heavy (720 kg). The treatments commenced at the start of the second grazing season (13 months of age, 360 kg liveweight) and ended with slaughter off pasture in the third grazing season. The reduction in fertiliser N level reduced (P<0.001) herbage production by 15% but had no effect on animal growth rate, slaughter traits, carcass composition or meat quality. Compared with by-products, silage increased carcass fat score (P<0.001) and muscle lipid concentration (P<0.05), reduced drip loss (P<0.05) and improved taste panel tenderness (P<0.05), flavour (P<0.05) and overall acceptability (P<0.01). Increasing slaughter weight increased killing-out proportion (P<0.05) and carcass fat proportion (P<0.001), reduced drip loss (P<0.01) and shear force (P<0.05) and improved (P<0.05) colour. It is concluded that the reduction in fertiliser N level reduced herbage yield and stock carrying capacity but had no effect on animal performance, carcass composition or meat quality. Crop by-products satisfactorily replaced silage as a winter feed and delaying slaughter increased carcass and muscle fatness.

Comparison of different dietary magnesium supplements on pork quality

Forty-eight crossbred (Large White×Landrace) boars were used to compare the effect of dietary magnesium aspartate (MgAsp), magnesium sulphate (MgSO 4) and magnesium chloride (MgCl 2) on muscle glycogenolysis and pork quality. The pigs were fed finisher feed supplemented with either MgAsp, MgSO 4 and MgCl 2 for 5 days prior to slaughter. At the abattoir, all pigs received 15 electric shocks from an electric goad 5 min prior to slaughter. Pigs fed the diet supplemented with MgSO 4 had the highest plasma Mg concentrations at slaughter in comparison with pigs fed the MgAsp and MgCl 2 supplemented diets. There were no differences in plasma adrenaline and noradrenaline concentrations at slaughter between the different diets. Pigs fed the Mg diets had higher muscle glycogen concentrations in the Longissimus thoracis (LT) muscle at 5 min and at 40 min (except MgCl 2) post-slaughter compared to pigs fed the control diet. Also pigs fed the Mg diets had lower muscle lactic acid concentrations in the LT at 5 min post-slaughter and lower drip loss at 24 hr post-slaughter compared to pigs fed the control diet. These results indicate that cheaper magnesium sources, MgSO 4 and MgCl 2, are as efficacious as MgAsp in reducing drip loss and improving pork quality.

Digestibility of α-tocopherol acetate in sheep

The principle role of α-tocopherol is to protect the polyunsaturated fatty acids of membrane lipids against peroxidation. The biological activity of α-tocopherol is very important in meat quality. Supplementation of cattle and pig diets with α-tocopherol acetate results in the production of meat which has an extended shelf life, greater colour stability and reduced drip loss (Vega et al 1994, Monahan et al 1994). Supranutritional supplementation with quantities of α-tocopherol acetate as high as 4000 mg d-1 have been reported in cattle (Arnold et al 1993). These high levels of supplementation have been shown to improve meat quality significantly. However, it is not clear if all of this α-tocopherol is absorbed or if the absorption of α-tocopherol becomes saturated leading to excretion of unabsorbed α-tocopherol. The present study was designed to measure the digestibility of α-tocopherol acetate in sheep when given at moderate and high levels.

Effect of vitamin E on α-tocopherol concentration in different tissues and oxidative stability of bull beef

The objective of the study was to examine the effect of vitamin E on α-tocopherol concentration in different tissues and oxidative stability of bull beef. In a 2 (length of vitamin E supplementation; 80 or 120 days)×3 (level of vitamin E supplementation; control, 600 or 2000 mg/animal/day) factorial experiment, 66 German Fleckvieh bulls (starting weight at 568±23 and 530±20 kg, respectively, for the two groups on the length of supplementation) were given 2.6 kg concentrate per day together with maize silage ad libitum up to the same mean slaughter weight of 641±29 kg. At slaughter, the intramuscular fat contents of the M. longissimus thoracis (MLT) and the M. semitendinosus (MST) were low, with mean values of 1.60 and 1.14%, respectively. The α-tocopherol concentrations in the serum, liver, kidney fat and muscle tissues increased with level and duration of supplementation. However, MLT and MST reached only mean α-tocopherol contents of 1.11 (600 mg–80 days) to 2.79 mg/kg (2000 mg–120 days), and 1.48 (600 mg–80 days) to 3.56 mg/kg (2000 mg–120 days) in vitamin E-supplemented animals in comparison with 0.56 and 0.65 mg/kg in controls, respectively. The level of vitamin E supplementation had a much clearer effect on the α-tocopherol concentrations in the tissues than did the duration of supplementation. The intensity of redness of the muscle tissue remained relatively constant in the supplemented groups up to a storage time of 7–9 days, arrived after 10 days of ageing time, whilst significant darkening of the meat was observed in the controls after 4 days. Vitamin E supplementation also resulted in a delay in the increase of metmyoglobin in the pigment fraction, in a reduction of fat oxidation and in a tendency for reduced drip loss. Duration of vitamin E supplementation tended to have a clearer effect than level of supplementation on meat colour and oxidative stability of bull beef.

Comparison of effects of dietary olive oil, tallow and vitamin E on the quality of broiler meat and meat products

1. The effect of dietary fat and vitamin E supplementation on quality attributes (drip loss, oxidative stability, sensory quality) in chicken meat and meat products was investigated. Broiler chicks were fed on diets containing tallow (60 g/kg) or olive oil (60 g/kg) at a basal (30 mg/kg diet) or supplemental (200 mg/kg diet) concentration of alpha-tocopheryl acetate for 8 weeks. The alpha-tocopherol content and fatty acid composition of breast and thigh meat was determined. Drip loss was determined in breast fillets. Lipid oxidation (thiobarbituric acid-reacting substances/TBARS) and sensory quality (warmed-over flavour development/WOF) were assessed in minced thigh meat during storage. 2. Dietary olive oil increased the ratio of monounsaturated to saturated fatty acids (MUFA/SFA) in the diets. In breast and thigh, this resulted in approximately a two-fold increase in the MUFA/SFA ratio. Supplemental alpha-tocopherol increased the alpha-tocopherol content of muscles. 3. Dietary fat did not influence drip loss in thawed breast fillets during refrigerated storage, but supplemental alpha-tocopherol reduced drip loss. 4. TBARS and WOF development in minced thigh meat patties were also reduced by supplemental alpha-tocopherol following frozen storage, or cooking and refrigerated storage. Storage stability was not adversely affected by dietary fat. 5. Overall, the results showed that increasing the monounsaturated profile of chicken meat lipids did not adversely affect quality characteristics. Dietary alpha-tocopherol supplementation was a more important factor in the determination of broiler meat quality.

Can pale, soft, exudative pork be prevented by postmortem sodium bicarbonate injection?

Previous attempts at eliminating the problem of PSE pork by genetic selection or rapid postmortem cooling have been only partially successful. A new approach, namely, postmortem injection of sodium bicarbonate (SBC), was tested on halothane-positive gilts. Sixteen pigs were used to establish a suitable SBC concentration. At approximately 15 min after death, the longissimus of one side of the carcass was injected with 10% (by weight) of .2 to .4 M SBC solutions containing .7% NaCl (wt/vol). All concentrations resulted in a higher ultimate pH, improved muscle color, and reduced drip loss. In a second experiment, with 23 pigs, .3 M SBC was injected into the longissimus and the biceps femoris at either 15 min or 24 h after death and with or without inclusion of .7% NaCl (wt/vol). Compared with controls, the 15-min SBC + NaCl injected samples had darker color (L* of 47 vs 53 in controls), higher ultimate pH (5.6 vs 5.3), lower drip loss (5% vs 10%), and increased protein solubility (140 vs 115 mg/g). Injection at 24 h reduced drip loss (from 10% to 5.7%) but did not correct the color defect. The SBC alone and SBC + NaCl treatments had essentially the same effects in reducing drip loss, increasing ultimate pH, and improving color; but the SBC-NaCl injected samples had improved juiciness and flavor compared with SBC. Early postmortem sodium bicarbonate injection seems to prevent the development of PSE pork when injected into carcasses of halothane-sensitive pigs.

Lower lipid oxidation in the muscle of rabbits fed diets containing oats

The susceptibility to oxidation of rabbit longissimus dorsi samples from animals receiving 300 g kg −1 oat in the feed was compared to samples from control animals receiving a diet based on barley. Dietary oat in rabbit diets balanced in digestible energy and protein did not affect feed efficiency, carcass weight and fatness. Also, intramuscular fat content was not affected by dietary treatment. Fat unsaturation, as assessed by the unsaturation index, was not modified by dietary treatment for neutral and polar lipids. After 8 days of storage thiobarbituric acid reactive substances (TBARS) of muscle samples from rabbits fed the control diet and rabbits fed the diet containing 300 g kg −1 oats were 1.32 and 0.67 mg malonaldehyde kg −1 muscle ( P < 0.001), respectively. Dietary oats also reduced drip loss in longissimus dorsi muscle ( P < 0.05). The presence of oat antioxidants and their possible synergistic effects suggest an interesting way of improving meat stability during storage.

Effect of dietary supplementation of vitamin E on pig meat quality

The effect of vitamin E on pig meat quality was investigated using British Landrace (NN and nn), Landrace × Large White (NN and Nn) and Pietrain (nn) pigs. Daily dietary supplementation of 500 mg vitamin E/kg diet for 46 days could reduce drip loss in unfrozen longissimus thoracis (LT) by 45% and 54% in Nn and NN pigs, respectively. In PSE-prone Landrace × Large White Nn pigs, daily supplementation of 1000 mg vitamin E/kg diet for the same period could significantly ( P < 0.001) reduce excess release of Ca 2+ and prevent the formation of PSE carcasses, evaluated from both biopsy and post- mortem LT samples. Experimental evidence from erythrocyte fragility and water-holding capacity of biopsy LT samples suggested that vitamin E improved pig meat quality by its ability to stabilize membranes. Stabilization of membrane integrity in isolated mitochondria of LT by vitamin E was associated with inhibition of phospholipase A 2 activity.

Effects of pre-slaughter administration of antifreeze proteins on frozen meat quality

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.

Effects of feed withdrawal before delivery on pork quality and carcass yield

A total of 270 pigs from a Yorkshire/Duroc/Landrace 3-way cross, reared under an ad libitum feed regimen, were delivered for slaughter after fasting (with access to water) for 24 and 0 h (Exp. 1), 16 and 0 h (Exp. 2) and 24, 16 and 0 h (Exp. 3). The interval between delivery and slaughter was 4–5 h. Feeding until delivery resulted in a lower pH at 45 min post mortem in the longissimus muscle. Ultimate pH values of longissimus and semimembranosus muscles were higher after feed restriction for 24 h. However, the incidence of dark, firm and dry (DFD) (pH > 6·2) was also increased after fasting in Exp. 1. Assessment of meat quality in samples taken from the longissimus at 20 h post mortem showed that, in comparison with feeding until delivery. Hunter L ∗ (Lightness)-values and drip loss decreased and firmness improved by prolonged fasting (24 h). Fasting for 16 h did not reduce drip loss, but colour was improved (lower Hunter L ∗-values) in Exp. 3, although not in Exp. 2. Feeding until delivery resulted in better meat quality in Exp. 2 than in Exp. 1 and 3. A significant reduction in dressing percentage as a result of fasting was only found in Exp. 1. There appears no economic disadvantage in restricting feed for 16 h prior to delivery. Although the incidence of DFD may also increase, a fasting period of 16–24 h is recommended to reduce pale, soft and exudative (PSE) muscle, while losses in carcass yield are minimized. Other advantages of fasting are discussed.

Hot deboning beef with and without electrical stimulation

Two hot deboning procedures for producing vacuum packed primal beef joints were compared with conventional side chilling followed by cold deboning. Cold shortening toughness was avoided in the hot procedures either by a delay before chilling or by electrical stimulation of the carcass. Overall evaporative losses were 0·6% with hot deboning and 1·9% with cold deboning. Hot deboning reduced drip loss but the effect was smaller after electrical stimulation. The colour of large muscles which cool unevenly on the side was more uniform after hot deboning, but again the improvement was smaller after electrical stimulation. There was no difference in bacterial contamination or growth on hot and cold deboned meat, and instrumental and sensory assessments confirmed that eating quality was similar for all three treatments.

Effect of Polyphosphates and Other Salts on Drip Loss and Oxidative Rancidity of Frozen Fish

Pretreatment of fresh fillets of Dover sole (Microstomus pacificus), Pacific cod (Gadus macrocephalus), halibut (Hippoglossus stenolepis), and red snapper (Sebastodes ruberrimus) with sodium tripolyphosphate prior to freezing was found to be effective in reducing drip loss during thawing. Sodium chloride, in a few trials, was effective in reducing drip and cooking losses. Tripolyphosphate and sodium citrate dip solutions of corresponding ionic strengths were equally effective in reducing drip loss during thawing from fillets of red snapper. Pretreatment of chinook salmon (Oncorhynchus tshawytscha) fillets with sodium tripolyphosphate preceding freezer storage was found ineffective in retarding lipid oxidation during storage at −10 °C; however, unlike sodium chloride, sodium tripolyphosphate did not accelerate development of oxidative rancidity.