Effect of dietary humate on the pH,TBARS and microbiological properties of vacuum‐ and aerobic‐packed breast and drumstick meats of broilers

The current trial determined the influence of dietary humate, including humic, fulvic and ulmic acids and some microminerals on the pH, TBARS and microbiological properties of vacuum‐packed and aerobic‐packed breast fillets and drumsticks of broilers. A total of 240 male broiler chicks (Ross‐308) were randomly allocated into four dietary treatments (H₀, H₁, H₂ and H₃ groups). A basal diet (H₀), basal diet plus 0.1 (H₁), 0.2 (H₂) and 0.3% (H₃) humate (Farmagulator DRY^?, Humate, Farmavet International Inc, Kocaeli 41 400, Turkey) were offered during the experimental feeding period. At the end of the trial all chicks were slaughtered. After standard dissection of carcasses, the breasts and drumsticks were divided into two groups for vacuum packaging or aerobic packaging. Packed breasts and drumsticks were stored at 3 °C for 12 days. The breasts and drumsticks were analyzed for pH, TBARS, total mesophilic, total psychrotrophic, lactic acid bacteria and Enterobacteriacea counts at 0, 2, 4, 6, 8, 10 and 12 days of storage. The feeding of humate decreased pH values of breast fillets and drumstick muscles (p < 0.01), especially at the 0.1% level. The TBARS value decreased (p < 0.01) when compared with the without‐humate group (H₀). Total aerobic mesophilic (p < 0.01), total aerobic psychrotrophic (p < 0.01) and lactic acid bacteria (p < 0.05) counts were lower in the H₃ group than the other groups. The effect of meat type on pH, TBARS, total aerobic mesophilic (p < 0.01) and lactic acid bacteria (p < 0.05) and Enterobacteriacea counts was significant. While the pH and TBARS values of breast fillets were lower than those of drumstick meats, the total mesophilic, total psychrotrophic, lactic acid bacteria and Enterobacteriacea counts of drumstick meats were higher than those of breast fillets. The effect of packaging type on pH (p < 0.01), TBARS (p < 0.01), total aerobic psychrotrophic bacteria (p < 0.01) and Enterobacteriacea counts (p < 0.01) was found statistically significant and the maximum values were determined in the aerobic‐packed samples. In addition, investigated parameters were also affected by storage period. While the total aerobic mesophilic count decreased, the other parameters increased when compared with zero day of storage. Copyright © 2005 Society of Chemical Industry     

Effects of dietary humate supplementation to broilers on performance,slaughter, carcass and meat colour

BACKGROUND: This experiment was designed to examine the effect of dietary humate supplementation primarily on pH and colour parameters of carcasses, breast fillets and drumsticks and, secondarily on performance and carcass characteristics in broilers. RESULTS: A total of 240 male broiler chicks (Ross‐308) were randomly allocated to four dietary treatments varying in supplemental humate level (0, 0.1, 0.2 and 0.3% for H₀, H₁, H₂ and H₃). Dietary humate supplementation did not affect performance traits and slaughter, hot carcass weights and yields. Carcass‐related variables (pH, L*, a*, b*, H* and C*) were responsive to the dietary treatments. The L*, a*, b*, and C* values for drumstick muscles were higher than those for breast muscles. Except for the L* value, meat colour parameters changed due to packaging. The a* value was higher and b* value was lower for vacuum packaged breast and drumsticks than for those aerobic packaged. Storage period affected colour parameters; while L*, b*, H* and C* values were higher for drumstick skin than for drumstick meat; the a* value was greater in drumstick meat than in skin. CONCLUSION: pH and colour parameters of carcasses, breast fillets and drumsticks of broilers were improved by dietary humate supplementation. However, responses of broiler performance and slaughter and carcass characteristics were minimal. Copyright © 2008 Society of Chemical Industry     

Presence and level of Campylobacter, coliforms, Escherichia coli, and total aerobic bacteria recovered from broiler parts with and without skin

This study was undertaken to determine if broiler chicken parts without skin are less contaminated with Campylobacter than those with skin. Samples were taken in a commercial plant from defeathered carcasses before evisceration. Bacterial counts from rinse of aseptically removed meat samples were lower than those from stomached skin samples. No Campylobacter were recovered from meat collected from the breasts or thighs, and only 2 of 10 drumstick meat samples had detectable levels of Campylobacter. However, 9 of 10 breast skin, 10 of 10 thigh skin, and 8 of 10 drumstick skin samples were positive for Campylobacter, with between 2 and 3 log10 CFU/g of Campylobacter. Breasts, thighs, and drumsticks were removed from broiler carcasses following evisceration before entering the chill tank. There was a significant difference (50 to 90%) in the levels of Campylobacter on breasts, thighs, and drumsticks with and without skin. Similar trends were noted for coliform, Escherichia coli, and total aerobic bacterial counts from samples collected in the plant. Broiler part samples were also collected at retail outlets. These samples were either skin on and skinned in the laboratory or skin off at purchase. Aseptic removal of skin from broiler breasts, thighs, and drumsticks did not cause change in Campylobacter, coliform, E. coli, or total aerobic counts recovered from the skinned part. Likewise, parts purchased without skin did not have different bacterial counts than paired parts purchased with the skin on. Consumers should not expect to significantly lower the number of bacteria present on a chicken breast, thigh, or drumstick by removing the skin.     

Effect of supplemental ram horn hydrolysate (RHH) at different levels on growth performance and slaughter traits of broilers

This study was carried out to determine the influence of ram horn hydrolysate (RHH) supplementation on the growth performance and slaughter traits of broilers. A total of 240 male broiler chicks (Ross 308), received from a commercial hatchery at 1 day of age, were allocated to four dietary treatments (H₀, H₁, H₂ and H₃ groups) in a completely randomized experimental design. Feed and water were offered ad libitum and lighting was continuous throughout the experimental period. The H₀ group was fed with basal diet plus normal drinking water. The H₁, H₂ and H₃ groups were fed with basal diet plus 1%, 2% and 3% RHH‐added water, respectively, in place of normal drinking water to meet the daily water requirements of broiler chicks from 1 to 28 days of age. All birds were housed in batteries from 1 to 21 days, and in grower broiler pens to 49 days. Feed intake and body weight gain were recorded weekly per pen. The average final body weights were 2524.9, 2601.2, 2441.7 and 2424.9 g for the H₀, H₁, H₂ and H₃ groups, respectively, and the difference was significant (P < 0.05). The average daily weight gains were 50.66, 52.25, 49.05 and 48.65 g, respectively, and the supplementation had no significant effect on this parameter. Daily feed consumptions were 96.18, 95.25, 91.70 and 90.75 g, respectively, and the difference between control and treatment groups was significant (P < 0.01). The feed conversion ratios (FCR) were, respectively, 1.79, 1.71, 1.73 and 1.81 (P > 0.05). At the end of the trial all birds were slaughtered to determine the slaughter traits. The hot carcass weights and yields were 1874.0, 1934.7, 1767.0, 1845.3 g and 75.78, 77.80, 75.00, 77.41%, respectively, and the difference was significant (P < 0.01). In addition, offal weights were determined and it was observed that there was no difference among the groups. Abdominal fat pad weights were similar in all groups. The H₁ group experienced more effects on some performance and slaughter traits than the control and the other RHH‐treated groups, and the supplementation of diets with RHH at a level of 1% improved broiler performance. Copyright © 2005 Society of Chemical Industry     

Changes in physical and sensory characteristics of marinated broiler drumsticks, treated with nisin and lactoperoxidase system

The lactoperoxidase system (LPS) and nisin have been shown to inactivate some micro‐organisms in foods. However, further studies were needed to evaluate whether these treatments had any influence on the physical and sensory characteristics of broiler drumsticks. In this study, a solution that contained 1% acetic acid and 3% salt with pH adjusted to 4 was developed as a standard marinade. The LPS consisted of 1‐μg mL^?1 lactoperoxidase, 5.9‐mm potassium thiocyanate (KSCN), and 2.5‐mm H₂O₂ was added to the marinade, followed by nisin at 100 IU mL^?1. The results showed that the physical characteristics, including raw and cooked drumstick pH, percentage incorporation of marinade solution, cooking loss, skin and muscle L*, a*, b* values, and sensory characteristics, including skin and muscle sensory colour, aroma and flavour, off aroma, off flavour, juiciness and tenderness of the broiler drumsticks, treated with 100‐IU mL^?1 nisin and LPS were not impaired.     

Influence of source and quality on the color characteristics of annatto dyes and formulations

Annatto dyes containing different strengths of bixin, norbixin and their formulations such as water-soluble liquid, and oil soluble liquid were measured for L*, a* and b* in a Hunter color meter and the Yellow (Y) and red (R) units in a Lovibond tintometer. Seed source and dye purity had a significant effect (P < 0.05) on the color characteristics L*, a*, b* and Y and R units of bixin/norbixin dyes and their formulations. These characteristics behaved independently when different dyes diluted to a common concentration of 50 mg bixin or norbixin/L. However, when individual bixin/norbixin dyes serially diluted L*, b* decreased and a* values increased with increase in concentration of bixin/norbixin. Similarly the increase in concentration of bixin/norbixin have shown decreasing trend on Y/R values due to increase in R-values in the tintometer. It has been observed that a* and R units generally increased with increase in concentration, and L* and b* values decreased and Y values are almost constant in both the bixin and norbixin dyes. However the b*/a* values showed lower values in bixin dyes and higher in norbixin dyes. Similarly R-values were higher in bixin dyes when compared to norbixin dyes.     

Effect of heating on physical properties and microstructure of black tiger shrimp (Penaeus monodon) and white shrimp (Penaeus vannamei) meats

Effects of heating on cooking loss, texture, colour and microstructure of black tiger shrimp (Penaeus monodon) and white shrimp (Penaeus vannamei) meats from different parts were evaluated. Cooking loss increased sharply when the samples were heated for longer time, particularly more than 1 min (P < 0.05). Among all parts, tail part of both shrimps had the highest cooking loss. The shear force of all samples increased markedly when the samples were heated for longer time, especially more than 0.5 min (P < 0.05). Black tiger shrimp and white shrimp meats had the slight differences in shear force either before or after heating. L*, a* and b*‐values increased when heating time increased up to 1 min (P < 0.05). Similar microstructures between raw meats of black tiger shrimp and white shrimp were found. Cooked meats of both species had more compact fibre arrangement with the shrinkage of sarcomere, compared with raw samples. Generally, tail portion showed the denser structure than other parts.     

Meat Color and Biochemical Characteristics of Unacceptable Dark-colored Broiler Chicken Carcasses

Spectrocolorimetry, pH, TBARS, total pigment and myoglobin were measured in normal and abnormally dark-colored broiler chicken breast muscle. Analyses of L*, a* and b* values revealed that a* values were highly sensitive and specific to differentiate normal from dark-colored carcasses and thus could be used as a potential diagnostic method for carcass classification at slaughter. Color characteristics (L*, a*, and b* values), pH, total pigment, myoglobin, and iron concentrations were all significantly different in dark-colored muscle when compared with normal muscle. TBARS values and percentage moisture for the two groups were not different.     

Effect of isoelectric solubilization/precipitation and titanium dioxide on whitening and texture of proteins recovered from dark chicken-meat processing by-products

Processing of chicken generates by-products containing muscle proteins attached to bones and skin that, if recovered, could be a functional ingredient in restructured food products. However, color of restructured products made of proteins recovered from chicken processing by-products is poor. The by-products contain bones, skin, fat, etc. that affect color of restructured products. Therefore, color properties need to be improved. The objectives of this study were to determine effects of isoelectric solubilization/precipitation (ISP) and TiO₂ on instrumental color and texture properties of heat-set gels made of proteins recovered from dark chicken-meat processing by-products as compared to gels made of chicken breast meat. Skin-on bone-in chicken drumsticks were used as a model dark chicken-meat processing by-products. TiO₂ at 0-1 g/100 g and canola oil at 10 g/100 g were added to the ISP-recovered proteins followed by cooking. Due to higher (P < 0.05) yellowness (b∗) and lower (P < 0.05) lightness (L∗), the whiteness of drumstick gels without TiO₂ was lower (P < 0.05) than breast gels. TiO₂ at 1 g/100 g with canola oil resulted in slightly better (P < 0.05) whiteness of drumstick gels than breast gels. TiO₂ did not deteriorate gel texture, which was generally comparable to breast gels. This research indicates that ISP allows recovery of proteins from skin-on bone-in dark chicken-meat processing by-products without removal of bones, skin, and fat prior to processing. Addition of TiO₂ to proteins recovered from these by-products allows development of heat-set gels with color and texture comparable to chicken breast gels. Although this study shows the potential for a novel, marketable food product, sensory tests are recommended.     

Changes of bioactive compounds and anti‐oxidant activity during cold storage of carrots

Carotenoids, total phenolics and anti‐oxidant activity of carrots were determined during 6 months of storage at 0 °C, 85–90% relative humidity. In addition to changes in CIE colour parameters (L*, a*, b*, h and C), physicochemical properties of carrots including water soluble solids; pH and titratable acidity were evaluated. Cold storage of carrots did not affect the carotenoid levels (β‐carotene, α‐carotene and total carotenoid) except lutein, which showed a 37.5% loss. Total phenolic concentration of carrots decreased significantly (P < 0.05) over the entire storage period. The anti‐oxidant activity of carrots decreased with a level of 31% and was found correlated with total phenolics and lutein content in carrots. While CIE L* and a* parameters decreased significantly (P < 0.05) after 6 months of storage, the b* and C parameters were statistically unchanged for the first 4 months of storage, but decreased gradually for the following period.     

Effects of different lairage times after long distance transportation on carcass and meat quality characteristics of Hungarian Simmental bulls

The objective of this study was to determine the effects of three lairage times (24 h, 48 h and 72 h) on the meat quality of tame trained to lead Hungarian Simmental bulls subjected to long commercial transportation of approximately 1800 km. A total of 30 bulls, with an average age of 24 months, were used. During the lairage, bulls received 0.5 kg concentrate feed per animal per day and ad libitum access to the hay and water. As the lairage duration increased, the pH_ult decreased (P < 0.05). Bulls lairaged for 24 h had lower L*, b* and H* values than those lairaged for 48 h and 72 h (P < 0.05). The effect of lairage time on WHC, cooking loss and Warner–Bratzler shear force values was not significant. The b* value was considered the best predictor of muscle pH_ult. In conclusion, 72 h quiet lairage time is recommended after transportation in order to prevent the adverse effects of transportation on meat quality.     

Protein denaturing conditions in beef deep semimembranosus muscle results in limited μ-calpain activation and protein degradation

The objective was to determine the effect of muscle location on protein solubility and protein degradation in deep (DSM) and superficial (SSM) portion of beef semimembranosus. At 24 h postmortem, the semimembranosus was removed from beef carcasses (n = 10), packaged in high-oxygen modified atmosphere (80% O₂ + 20% CO₂), and displayed for 7 d at 1 °C. DSM had higher (P < 0.05) L*, a*, b*, and hue values than SSM throughout display. DSM had significantly higher protein denaturation and less protein concentration than SSM. Western blotting for μ-calpain autolysis revealed that DSM maintained more (P < 0.05) unautolyzed μ-calpain than SSM. This result coincided with less desmin and troponin-T degradation in samples from the DSM. These results confirm the hypothesis that increased protein denaturation in DSM results in minimal proteolysis by negatively affecting μ-calpain activation. This demonstrates a potential to alter progression of proteolysis and improvement in tenderness associated with postmortem storage.     

Effects of stress by unfamiliar sounds on carcass and meat traits in bulls from three continental beef cattle breeds at different ageing times

One-hundred-and-twenty-four young bulls of three Continental beef cattle breeds were used to study the effect of pre-slaughter stress by unfamiliar sounds on carcass traits and quality characteristics of beef aged for three different periods. Stress due to unfamiliar noises had a moderately negative effect on carcass and meat quality. Carcasses from group Stressed had higher (P < 0.05) values of pH₀, pH₂₄, a*, and Warner-Bratzler shear force, and lower (P < 0.05) values of L*, b* and pressure losses than from Unstressed animals. There were significant differences (P < 0.05) among breeds in L*, a* and pressure losses. The ageing time had a significant effect on chromatic variables, WBSF and pressure losses. The cooking losses were not significantly affected by any of the three factors discussed. These results emphasize the importance of implementing appropriate management practices during pre-slaughter handling of cattle in order to reduce any possible risk factor for stress, as well as the different sensitivity of the breeds to similar stimuli.     

Screening of phytochemicals in fresh lamb meat patties stored in modified atmosphere packs: influence on selected meat quality characteristics

This study was carried out to determine the antioxidant activity of phytochemicals and plant extracts in fresh lamb patties. Quality indices such as colour (Hunter L* a* b*), lipid oxidation (TBARS) and pH were measured over an 8‐day storage period. Resveratrol, citroflavan‐3‐ol, olive leaf extract and Echinacea purpurea were added to raw minced M. longissimus dorsi lamb patties, at concentrations ranging from 0–400 mg kg^?1 lamb meat, stored in high oxygen modified atmospheres packs (75% O₂:25% CO₂) for up to 8 days at 4 °C. The pH of the lamb meat was not significantly affected by the addition of the phytochemicals and plant extracts examined (P > 0.05). Resveratrol and citroflavan‐3‐ol decreased (P < 0.05) lipid oxidation in raw lamb patties during storage and increased a* values (P < 0.05), relative to controls. By contrast, olive leaf extract and Echinacea purpurea did not exhibit antioxidant activity or promote higher a* values relative to controls. Results obtained demonstrate potential for the development of functional meats using plant extracts such as resveratrol and citroflavan‐3‐ol.     

Evaluation of animal age and muscle type on beef log juice colour and residual GOT activity when cooked to target end-point temperature of 79.4 °C†

The effectiveness of the pink-juice test to determine 79.4 °C end-point temperature (EPT) of cooked beef logs was appraised. Logs made from five cuts of meat from three animal age groups were fabricated in triplicate to simulate products received at ports of entry and then cooked to EPTs of 78.0–81.8 °C. CIELAB L*, a*, b*, C and h ° values of internal surfaces of freshly sliced meat and pressed juices from samples were determined. Sensory ratings were made by six trained panelists to determine intensities of residual red color of the juices. Animal age and cut of meat had little effect on the CIELAB color values. Residual red color was apparent in all samples by both sensory and a* values analysis. Sensory ratings did not vary significantly (P < 0.05) by animal age or cut of meat. Average values of 3.2 (intensity range, 1–9) corresponded to an EPT slightly greater than 80 °C; absence of red color in the juices would therefore indicate an EPT in excess of the target temp of 79.4 °C. Residual glutamic-oxaloacetic transaminase activity (GOT) activity, used as a collateral test for EPT, ranged from 482.5 to 1641.8 SFU ml⁻¹ of juice and differed significantly by cut of meat (P < 0.05), but not by animal age. © 1999 Society of Chemical Industry     

Effect of enriched housing on welfare,production performance and meat quality in finishing lambs: The use of feeder ramps

This study analyses the effect of environmental enrichment on the welfare, productive traits and meat quality of lambs housed in feedlots. Sixty lambs were placed in enriched (EE) or conventional (CO) pens (3 pens for each treatment, 10 lambs/pen) where EE had a wooden platform with ramps that provided access to a concentrate hopper, cereal straw as bedding and forage, and one play ramp. The CO pen was barren, similar to commercial feedlots. The physiological adaptation response of EE lambs was more efficient than CO, since the latter mobilised more body reserves (i.e., increased NEFA, P < 0.05), and had lower levels of immunity (i.e., increased N/L, P < 0.05), which indicate chronic stress, probably associated with the barren environment. The EE lambs had a higher (P < 0.05) average daily gain, with heavier carcasses and higher fattening scores, as well as lower pH_ult, higher L* and b* values, and lower values of texture (P < 0.05).     

不同冻藏条件对鸡胸肉品质特性的影响

为研究不同冻藏条件对鸡胸肉品质特性的影响,本实验以新鲜鸡胸肉为原料,于-16、-26和-36 ℃分别冻藏1、2、3、4、5、6个月,分析比较不同冻藏温度和时间对鸡胸肉的系水力、色泽、蛋白质变性程度、嫩度、脂肪酸败及新鲜度的影响情况。结果表明,随着冻藏温度的升高及冻藏时间的延长,pH呈现先降低后升高的趋势,鸡胸肉的解冻损失率、蒸煮损失率、剪切力以及b*值也逐渐增加,L*值、总蛋白及肌原纤维蛋白溶解度显著降低(p<0.05),但对肌浆蛋白的溶解度无显著影响(p<0.05);a*值则在冻藏前1个月显著增加(p<0.05),但随后逐渐降低,且随着冻藏温度升高而减小(p<0.05)。衡量系水力指标的解冻损失和蒸煮损失结果,衡量色差的L*、a*和b*值以及衡量蛋白变性指标的三大蛋白溶解度和TBARS值与TVB-N值均表明,鸡胸肉在冻藏温度为-36~-26 ℃及冻藏时间为5个月内能有效维持较好的鸡胸肉食用品质。此外,各指标间的相关性分析表明,不同冻藏条件下解冻损失率、蒸煮损失率、剪切力、TVB-N值、TBARS值、a*值、b*值、蛋白溶解度与新鲜鸡胸肉呈现显著的差异(p<0.05),而pH、L*值与新鲜鸡胸肉差异不明显(p>0.05)。本文为快速发展的冷冻禽肉的加工及贮藏环境提供了理论依据。     

Effect of modified atmosphere and vacuum packaging on some quality characteristics and the shelf-life of “morcilla”, a typical cooked blood sausage

The effect of modified atmosphere and vacuum packaging on the shelf-life of “morcilla”, a traditional cooked blood sausage, was investigated. A total of 99 “morcillas” were packaged under vacuum and in modified atmosphere using three different gas mixtures: 15:35:50/O₂:N₂:CO₂ (atmosphere 1), 60:40/N₂:CO₂ (atmosphere 2) and 40:60/N₂:CO₂ (atmosphere 3), and stored during 2, 4, 6 and 8 weeks at 4 °C. Shelf life evaluation was based on pH, water activity (a_w), colour (CIE L*, a*, b*, C* and h*), TBARS formation and microbial counts. The results indicated that, in general, storage time affected (P < 0.05) all parameters whereas no significant differences were observed (P > 0.05) among packaging conditions. Based on the microbial counts, the shelf-life of “morcilla” would be greater than 8 weeks for all packaging conditions. Samples packaged with high CO₂ concentrations (40:60/N₂:CO₂) showed the lowest values of TBARS at the end of storage.     

Effect of Asian sea bass bio-calcium on textural,rheological, sensorial properties and nutritive value of Indian mackerel fish spread at different levels of potato starch

Effect of potato starch (2%–4%) and Asian sea bass bone bio-calcium (BC) (0%–10%) on characteristics of Indian mackerel fish spread was investigated. Starch levels had higher impact than bio-calcium concentration on characteristics of fish spread (P < 0.05). Firmness, consistency and cohesiveness of fish spread were raised with increasing starch and BC levels (P < 0.05). Highest lightness (L*) was found in fish spread added with 2% starch and 10% BC (P < 0.05). Highest a*, b*, C*-values but lowest hue angle were obtained in fish spread added with 4% starch and 10% BC (P < 0.05). Higher G' and viscosity were observed in sample added with 4% starch when BC was incorporated at higher level. All fish spreads generally showed shear thinning flow behaviour. Higher acceptability was attained for fish spread containing 4% starch and 10% BC without grittiness. This fish spread showed higher ash with lower moisture, protein and lipid contents than those without BC. Calcium solubility of fish spread was augmented after in vitro gastrointestinal tract system when fortified with 10% BC, and higher solubility of calcium was also noticeable, compared to BC itself. Overall high PUFA, acceptable PV and TBARS value were attained for fish spread fortified with 4% starch and 10% BC.     

Carcass quality,physico-chemical parameters,muscle fibre traits and myosin heavy chain composition of m. longissimus lumborum from Puławska and Polish Large White pigs

In 54 Puławska pigs and 60 Polish Large White pigs (PLW), slaughtered at 30 and 100 kg body weight, carcass and meat quality of m. longissimus lumborum were studied. Analysis revealed that in both examined body weight groups, hot carcass weight, carcass yield percentage, meat content, and weight of ham and carcass ham percentage were significantly lower and backfat thickness higher for Puławska pigs compared to PLW pigs, while PLW pigs exhibited significantly longer carcasses, greater loin eye area, and, in the case of lighter pigs, smaller proportion of loin in the carcass. Muscles of Puławska pigs, in the lighter group, had higher IMF content and a* value, while in the heavier group they exhibited higher pH₄₅, pH₂₄ and a* values, lower L*, drip loss, WHC, and thermal loss compared with PLW pigs. PLW pigs had higher WB and hardness values and more glycolytic muscles characterised by higher TNF.