Incidence and physical properties of PSE chicken meat in a commercial processing plant

Evaluation of homemade fermented pickle juice as a marinade: Effects on the microstructure, microbiological, physicochemical, textural properties, and sensory attributes of beef strip loin steaks

The current study aimed to characterize homemade fermented pickle juice and evaluate its efficacy as a marinade on physicochemical, microbiological, textural properties, microstructure, and sensory attributes of the strip loins. Organic acids, phenolics, flavonoids, volatiles, total phenolic content (TPC), and in-vitro antioxidant capacity (ABTS and FRAP) analyses were carried out. Furthermore, minimum inhibitory concentration (MIC), and the diameter of inhibition zones of the pickle juice were determined against Escherichia coli O157:H7, Salmonella Typhimurium, S. enteritidis, and Listeria monocytogenes. The strip loins were marinated with five different concentrations (10%, 25%, 50%, 75%, and 100%) of pickle juice at 4 °C for 24 h. A total of 4 organic acids, 23 phenolic and flavonoid compounds, and 69 volatiles were identified in the pickle juice. The TPC, ABTS, and FRAP values of the pickle juice were found to be 184.24 ± 33.28 GAE/L, 44.48 ± 0.41 mg TEAC/L, and 2.79 ± 0.01 mM FE/L, respectively. The MIC and inhibition zones were recorded between 7.81 and 12.50% and 8.25-13.80 mm against pathogenic bacteria, respectively. The textural properties of the strip loins marinated with 100% pickle were improved compared to the control (P < 0.05). Moreover, this concentration decreased the number of pathogens in strip loins, ranging between 1.07 and 2.77 log10 CFU/g (P < 0.05). Regarding sensory attributes, the strip loins marinated with 50% and 100% pickle juice had higher scores compared to the non-marinated samples. The results of this study indicated that pickle juice can be evaluated as a marinade to improve the microbiological quality and textural properties of strip loins.

Growth performance, welfare traits and meat characteristics of broilers fed diets partly replaced with whole Tenebrio molitor larvae

The role of insects in animal nutrition has been reconsidered during recent years, paving the way for an increasing market for edible insects. Their protein and amino acid balance make them a promising source of protein for replacing high value proteins. Yellow mealworm, Tenebrio molitor L. (TM; Coleoptera: Tenebrionidae) larvae, have shown positive effects on broiler performance in several research studies and have a strong potential as a sustainable alternative protein source for monogastric animals. This study aimed to assess the effect of replacing various ratios of basal diets with T. molitor larvae on broiler performance as well as on several meat and welfare characteristics. For the study, 120 one-day-old male chicks (Ross 308) were randomly allocated in 3 treatments and 4 replications (10 birds per pen). Birds of the control group (basal diet) were fed with typical commercial maize and soymeal-based rations in mash form. The other 2 groups were treated with the same diet, after replacing 5% and 10% with dried TM larvae, respectively. On d 35 (end of trial), meat samples were collected and analysed. Body weight, feed intake, body weight gain and feed conversion ratio during the periods of 1 to 10 d (starter period), 11 to 24 d (grower period), 25 to 35 d (finisher period) and 1 to 35 d (total period) were assessed. Pododermatitis, diarrhoea, feather score and litter conditions were also assessed during the trial. The results indicated that TM larvae inclusion in the broilers' diet positively affected body weight gain values, as well as the carcass yield, the meat composition and various welfare traits. Additionally, the dietary treatments with TM larvae favourably affected meat composition and colour parameters, whereas there were also some positive effects on lipid and protein oxidation. Saturated fatty acids were decreased by the dietary supplementation whereas the polyunsaturated fatty acids to SFA ratio increased. In general, the study showed that whole TM larvae addition can provide a promising alternative to soybean meal in the diet of broilers, demonstrating a positive impact on growth, welfare and meat characteristics.

Enteromorpha polysaccharide and yeast glycoprotein mixture improves growth, antioxidant activity, serum lipid profile and regulates lipid metabolism in broiler chickens

This study aimed to analyze the growth performance, antioxidant activity, serum lipid profile, meat quality, and lipid metabolism of broiler chickens fed mixtures containing Enteromorpha polysaccharide (EP) and yeast glycoprotein (YG). A total of 400 one-day-old broiler chickens were randomly divided into 4 treatment groups of 10 replicates with 10 birds each replicate. The dietary treatments consisted of the control group (fed basal diet), and diets supplemented with Enteromorpha polysaccharide (EP; 400 mg/kg), yeast glycoprotein (YG;400 mg/kg), and EP+YG (200 mg/kg EP + 200 mg/kg YG). Compared with the control group, EP+YG supplementation enhanced growth performance and significantly reduced (P < 0.05) serum total triglyceride (TG), cholesterol (CHOL), and low-density lipoprotein LDL levels, and increased high-density lipoprotein (HDL) levels. Besides, birds fed EP+YG supplemented diet exhibited higher (P < 0.05) serum catalase (CAT), total antioxidant capacity, superoxide dismutase (SOD), and lower malonaldehyde (MDA) activities, and upregulated expressions of related genes, such as nuclear factor-erythroid factor 2-related factor 2 (NRF2), SOD1, and glutathione peroxidase 4 (GPX4) in the liver and intestinal tissues than the control group. Interestingly, higher (P < 0.05) serum SOD and lower MDA contents were observed in the EP+YG group than in either EP or YG group, suggesting a synergetic effect. Breast meat from EP+YG supplemented group had significantly higher redness value (a*), and lower pH24, total saturated fatty acid profiles, C14:0, C16:0, C18:0 fatty acid, atherogenic index, and thrombogenicity index than meat from the control group (P < 0.05). Furthermore, the mRNA expressions of fatty acid synthesis genes were downregulated (P < 0.05), whereas lipid β-oxidation-related genes were upregulated (P < 0.05) in the liver of the EP+YG supplemented group than in the control group. Overall, our data suggest that dietary EP+YG inclusion may have a synergistic effect, and therefore improve growth performance, regulate serum biochemical indexes, enhance antioxidant activity, and modulate lipid metabolism in broilers, indicating that it is a potential feed additive for chickens.

A comparative study of acute heat tolerance and meat quality in three chicken breeds

In order to breed a strain that has heat tolerance and meat productivity, the commercial red-feathered Taiwan native chickens were male (F group), and heat stress resistant strain Taiwan native chickens (Taishu-9, bred by the Taiwan Livestock Research Institute) were female (TR9 group) to hybridize to generate offspring (F9 group). Three breeds of birds (male) were conducted to compare acute heat stress and meat quality. At 12 weeks of age, TR9 group showed the significantly lowest activity of plasma creatine kinase upon acute heat stress which indicated heat stress resistant in TR9 group as expected. In addition, only limited thermoregulation was obtained in F9 group, while F group exhibited almost no acute heat stress tolerance ability. After slaughtered at 16 weeks of age, the F group revealed poor meat quality in breast meat as pale, soft, and exudative (PSE)-like muscle samples according to CIE L* and pH value. The F9 group was an offspring of TR9 group with heat tolerance, but it only demonstrated limitation of heat resistance. However, the improve meat quality was obtained in F9 group compared to F group, and that may be contributed from better anti-stress as like as TR9 group during slaughtering process.

Properties of broiler breast meat with pale color and a new approach for evaluating meat freshness in poultry processing plants

The current trend in monitoring meat quality is to move the quality measurements from the laboratory to the processing line. To provide better meat quality control in the commercial poultry processing plants, we evaluated the quality of broiler breast meat samples, observing different colors, and assessed their freshness using a Torrymeter. Different colors were classified based on the mean ± standard deviation of lightness (L*) values in 1,499 broiler breast fillets: Dark (L* < 56), normal (56 ≤ L* ≤ 62), and pale (L* > 62). To characterize the differences between the pale and normal color groups, we evaluated additional fillets for meat quality traits. Changes in meat quality during storage were also evaluated. The L* and Torrymeter values (freshness values) allowed us to distinguish between the pale and normal meat samples. Normal and pale fillets showed a significant difference in pH, Torrymeter values, and water-holding capacity (P < 0.001). The L* values were significantly correlated with cook and drip loss (P < 0.01) and were higher (paler, +1.2 L* unit) at 72-h postmortem than at 4-h postmortem. Torrymeter values were correlated with cook loss (P < 0.05) and pH (P < 0.001), and significantly decreased with the increase in storage period (P < 0.001). These results suggest the applicability of the Torrymeter, a fast and non-destructive device, in distinguishing stale and fresh breast fillets. With its portability and simplicity, the Torrymeter is expected to be a valuable tool to estimate meat freshness. Especially, the use of Torrymeter for evaluating pale breast fillets may allow easy identification and separation of fillets according to their pale, soft, and exudative properties in commercial poultry processing lines.

A fluorescent pH probe for evaluating the freshness of chicken breast meat

A fluorescent probe, Nap-MOR, based on the naphthalimide fluorophore, was designed and developed for pH measurement in aqueous solutions. Nap-MOR had a close linear relationship between fluorescence intensity and pH, in the range 4.5-8, which covers the full range of pH found in normal fresh, defective and spoiled meat. pH measurement with Nap-MOR was free from interference by a wide range of ions and biochemicals found in meat and the results were not significantly different in comparison with a pH meter. Therefore, Nap-MOR is a robust and convenient way to evaluate the freshness of chicken breast meat by measuring its pH.

Metabolomic analysis indicates that higher drip loss may be related to the production of methylglyoxal as a by-product of glycolysis

The aim of the present study was to assess applicability of metabolomics analysis of exudate from chicken breast muscle to explanation of differences in drip loss. The research was carried out on the skinless breast fillets sourced from 60 broiler carcasses (7-wk-old male Ross broilers). In the meat samples the pH value, color parameters, drip loss, chemical composition, and sensory quality were evaluated. After measuring, the samples were divided into 2 groups taking into consideration the volume of drip loss (low ≤2% and high >2% drip loss). The muscle juice samples were collected during 24 h muscle storage and metabolomic analysis was performed. The results showed that chickens with higher drip loss were characterized by heavier carcasses. The meat with higher drip loss proved to be more acid, lighter, less red, and more yellow with higher level of glucose as well as glycolytic potential. That meat was also characterized by lower cooking loss, protein content and worse overall sensory quality as well as oxidation of lipids. The metabolomics analyses have shown that in the group with higher drip loss from muscle tissue the increase of metabolism of energy transformations taking place in muscle tissue after slaughter was observed and that differences between groups are related to 11 metabolic pathways, mainly carbohydrate metabolism (glycolysis, gluconeogenesis, pentose phosphate pathway) adenine and adenosine salvage, adenosine nucleotides degradation, arsenate detoxification, methylglyoxal degradation. Finally, the results indicate that in the group with higher drip loss and with deeper glycolysis, more methylglyoxal (as a by-product of carbohydrate metabolism) is produced which may lead to changes of muscle proteins properties and contribute to an increase in drip loss.

Meta-analysis to predict the effects of temperature stress on meat quality of poultry

Temperature stress (TS) is a significant issue in poultry production, which has implications for animal health and welfare, productivity, and industry profitability. Temperature stress, including both hot (heat stress) and cold conditions (cold stress), is associated with increased incidence of meat quality defects such as pale, soft, and exudative (PSE) and dark, firm, and dry (DFD) meat costing poultry industries millions of dollars annually. A meta-analysis was conducted to determine the effect of ambient TS on meat quality parameters of poultry. Forty-eight publications which met specific criteria for inclusion were identified through a systematic literature review. Temperature stress was defined by extracting 2 descriptors for each treatment mean from the chosen studies: (1) temperature imposed for the experimental treatments (°C) and duration of temperature exposure. Treatment duration was categorized for analysis into acute (≤24 h) or chronic (>24 h) treatments. Meat quality parameters considered were color (L*-a*-b* scheme), pH (initial and ultimate), drip loss, cooking loss, and shear force. Linear mixed model analysis, including study as a random effect, was used to determine the effect of treatment temperature and duration on meat quality. Model evaluation was conducted by performing a k-fold cross-validation to estimate test error, and via assessment of the root mean square prediction error (RMSPE), and concordance correlation coefficient (CCC). Across both acute and chronic durations, treatment temperature was found to have a significant effect on all studied meat quality parameters. As treatment temperature increased, meat demonstrated characteristics of PSE meat and, as temperature decreased, meat demonstrated characteristics of DFD meat. The interaction between treatment temperature and duration was significant for most traits, however, the relative impact of treatment duration on the studied traits was inconsistent. Acute TS had a larger effect than chronic TS on ultimate pH, and chronic stress had a more considerable impact on color traits (L* and a*). This meta-analysis quantifies the effect of ambient TS on poultry meat quality. However, quantitative effects were generally small, and therefore may or may not be of practical significance from a processing perspective.

Cooked broiler meat quality affected by different Mediterranean medicinal plants in the diet

Objective

This study was conducted to investigate the effects of adding oregano (Origanum syriacum L.) and germander (Teucrium polium L.) to poultry diets individually and/or in combination: i) on cooked chicken meat quality and storage stability, ii) to compare this effect with those of the synthetic antioxidant butylated hydroxyanisole (BHA) and with the normal basic diet (Control: without supplements).

Methods

Broilers (140 birds) were raised for 21 days and then equally divided into five different treatment groups of 28 birds each. The dietary treatments were as follows: i) control; ii) germander (GER, 1.5%); iii) oregano (ORE, 2.5%); iv) combination of GER and ORE (CM, 1.5%, and 2.5%); v) BHA (0.02%). Meat patties from the five treatments were prepared, cooked, and stored at 4°C prior to analysis. During storage, samples were measured for thiobarbituric acid-reactive substances (TBARS) and total carbonyl levels at 0, 4, and 7 days. In addition, cooked thigh meat was prepared separately to evaluate cooking loss and sensory attributes.

Results

The CM dietary treatment showed the highest antioxidant effect, with decreasing TBARS values (breast and thigh meat) throughout the storage time (4 to 7 days). Furthermore, ORE showed a higher antioxidant effect, decreasing the rancidity development (TBARS values), compared to the GER during the storage period (days 0 to 7). The anti-carbonyl effect of the CM supplement was the highest among all treatments from day 0 to 7. Generally, the antioxidant effect of GER was lower compared to that of ORE and BHA alone. The CM treatment most significantly decreased off-odor and rancidity development, with the lowest oxidation odor scores.

Conclusion

The results indicate that the combination of oregano and germander in the diet of boilers improves meat quality and prolongs shelf life.

The Role of Coffee Silver Skin against Oxidative Phenomena in Newly Formulated Chicken Meat Burgers after Cooking

Coffee Silver Skin (CSS) is the unique by-product discarded after the roasting of coffee beans. This research aimed to evaluate the effect of two levels of CSS (1.5% and 3%) added as a natural ingredient in new formulations of chicken meat burgers. This is one of the first studies proposing a "formulation approach" to control the emergence of off flavours after meat cooking. Physical, chemical, and sensory analyses were carried out, within the CSS content and the evolution of volatile organic compounds in different samples. Newly formulated chicken burgers could limit food waste, while also becoming a source of fibres, minerals, and bioactive molecules. CSS limited weight losses (after cooking process) to 10.50% (1.5% addition) and 11.05% (3% addition), significantly lower (p < 0.01) than the control (23.85%). In cooked burgers, the occurrence of hexanal was reduced from 55.1% (CTRL T₀) to 11.7% (CSS T₀ 1.5%) to 0 (CSS T₀ 3%). As for the limitation of off-flavours, CSS also showed good activity, contrasting with the emergence of octanal, alcohols and other markers of lipid oxidation. From the sensory test carried out, the volatile profile of CSS does not seem to impair the flavour of burgers, though at higher percentages hydrocarbons and pyrazines are traceable. The thiobarbituric acid reactive substances (TBARS assay confirmed the protective effect of CSS against oxidation.

Effect of pomegranate (Punica granatum L) peel powder meal dietary supplementation on antioxidant status and quality of breast meat in broilers

This study examined the antioxidant status and quality of breast meat in broiler birds fed diets supplemented with pomegranate peel powder meal (PPPM). During the 35-d feeding trial, broiler birds were fed six experimental diets: diet with 0% additives (negative control; NEGCON); diet with α-Tocopherol acetate at 200 g/tonne (positive control; POSCON); and four levels (2, 4, 6 and 8 g/kg) of PPPM, designated as PPPM₂, PPPM₄, PPPM₆, and PPPM₈. Breast muscle pH was determined 15mins and 24hrs postmortem. The breast muscles were then stored at 4 °C to determine shelf-life attributes (pH, colour, hue angle, and chroma) for 16 days. Meat from the 8 g/kg PPPM had the highest thawing loss, whereas cooking loss was lowest at 2 g/kg PPPM inclusion. The meat of birds fed 2 g/kg and 4 g/kg PPPM had the highest (P<0.05) ability to scavenge the ABTS [(2, 2-azinobis (3ethylbenzothiazoline-6 sulfonic acid))] radical cation (ABTS⁺), whereas, catalase activity was increased at 8 g/kg PPPM. The results obtained in this study indicate that 2 g/kg supplementation of pomegranate peel powder meal significantly improved the water-binding capacity of broiler breast meat, owing to the reduced cooking loss of the meat, and meat from the PPPM₂ (2 g/kg) group had the highest ability to scavenge ABTS.

Effectiveness of using a hybrid rye cultivar in feeding broiler chickens

The aim of this research was to evaluate the effectiveness of the use of hybrid rye in rations for broiler chickens. The study covered 160 chickens split into four equal groups [I (control), II, III, IV] and kept for 42 d. Rye was introduced into the above-mentioned diets as a partial substitute for maize in the following quantities: (I), no rye; (II), 5% rye in starter feed and 10% rye in grower and finisher feed; (III), 10% rye in starter feed and 20% rye in grower and finisher feed; (IV), 15% rye in starter feed and 30% rye in grower and finisher feed. During the 42 d rearing period, the most favourable body weight gain (P ≤ 0.05) and feed conversion ratio (P ≤ 0.01) were observed in chickens fed with rations containing the highest share of hybrid rye (group IV). The rye did not affect the dressing percentage and muscularity but diversified the fatness of birds. The muscles of chickens from group IV showed higher (P ≤ 0.01) red saturation and lower (P ≤ 0.01) yellow saturation and hue compared with the muscle of birds receiving diets with the lowest rye content (group I). The results of the study show that the inclusion of hybrid rye can be recommended in broiler chicken diets at a share of 15% in starter feed and 30% in grower and finisher feed, respectively.

Meat quality and sensory attributes of meat produced from broiler chickens fed a high oleic peanut diet

Previous studies have identified peanut meal prepared from normal-oleic peanuts as a suitable and economical ingredient for broiler feed. However, to date, no studies have examined the use of new, high-oleic peanut (HO-PN) cultivars as a feed ingredient for poultry. This project aimed to determine the effect of HO-PNs as a feed ingredient for broiler chickens on the quality and sensory attributes of the meat produced. To test 3 experimental diets, male broiler chicks were randomly placed, at hatch, in raised-wire cages, in 10 replicate pens per treatment with 10 chicks per cage. For 6 wk, chicks were fed, ad libitum, one of the three isocaloric, isonitrogenous diets: (1) a conventional soybean meal plus corn control diet, (2) 10 to 12% HO-PN + corn diet, or (3) a control corn diet spiked with ≈6.0% oleic fatty acid oil (OA). At 42 D, 3 broilers per pen (30 per treatment) were processed to determine meat quality and for consumer evaluation. Carcass weights and breast yields were reduced in broilers fed HO-PN, while leg carcass yields were greater in broilers fed HO-PN in comparison to the other groups. Chicken breast from broilers fed HO-PN had reduced meat-pH, reduced L* color values, and increased cooked loss compared to other treatments. Nevertheless, a group of 100-consumer panelists scored all 3-treatment groups similar in terms of sensory attributes for cooked chicken. While additional studies must be performed, this study suggest that HO-PN may be a suitable broiler feed ingredient.

Chemical and color characterization of breast meat from FUNAAB indigenous and marshal broiler chickens

The study was conducted to evaluate breast meat quality attributes of Marshal and FUNAAB Indigenous (Alpha C13 and Alpha C14) Broiler (FIB) chickens. Birds of average live weights (1.8 to 2.0 kg) were selected from flock fed same concentrate diet and managed under deep litter system. Birds were slaughtered, scalded in hot water at 65 °C, de-feathered, and frozen-stored. Proximate, mineral, cholesterol contents, pH, color, and fatty acid profile of the chickens' meat were determined. Data were subjected to ANOVA (p < 0.05). Moisture (73.87%) and fat (2.82%) contents of Marshal were higher than FIB. Protein (23.65%) and ash (1.56%) were highest (p < 0.05) for Alpha C14. pH ranged between 5.94 and 6.58. Lightness (L*) and redness (a*) values were 69.37-75.52 and 8.77-7.96. Alpha C13 had significantly higher L* and a* than Marshal. Potassium was most abundant mineral observed across breeds. Saturated (SFA, 38.03-57.10%), monounsaturated (MUFA, 29.78-41.55%), and polyunsaturated (PUFA, 10.91-20.29%) fatty acid compositions differed significantly among breeds. Cholesterol contents of Alpha C14 (4.23 mg/kg) was significantly lower, while Marshal (5.67 mg/kg) chicken showed significantly higher value. Conclusively, FIB chickens are valuable nutritional meat sources with desirable chemical composition and can constitute alternative chicken meats with human health benefit.

Influence of Different Production Systems on the Quality and Shelf Life of Poultry Meat: A Case Study in the German Sector

Production-specific factors, such as breeding, diet, and stress, are known to influence meat quality, but the effect of different husbandry systems on the development of quality parameters and shelf life has hardly been investigated. Thus, the aim of the study was the investigation of an alternative production system based on a slow-growing, corn-fed, and antibiotics-free chicken line compared with conventional poultry production. Additionally, the effect on meat quality, microbiology, and spoilage was analyzed. In total, 221 breast filets from a German poultry meat producer were investigated. Nutritional, biochemical, and cooking loss analyses were conducted on a subset of samples 24 h after storage. The rest of the samples were stored aerobically at 4°C, and the spoilage process was characterized by investigating pH, color, lipid oxidation, microbiology, and sensory attributes subsequently every two days during storage. The alternative production line showed a significantly healthier nutritional profile with a higher protein and lower fat content. Additionally, the amount of L-lactic acid and D-glucose was significantly higher than in the conventional production line. The color values differed between both production lines, with the corn-fed line displaying more yellowish filets. The lipid oxidation and microbial spoilage were not affected by the production line. The shelf life did not differ between the investigation groups and was deemed 7 days in both cases. Despite the highest severity of white striping being observed most in the conventional production line, there was no overall difference in the incidence among groups. The purchase decision was affected by the occurrence of white striping and showed a tendency for a higher acceptance for the alternative production line.

Assessment of Meat Quality and Shelf Life from Broilers Fed with Different Sources and Concentrations of Methionine

A trial with different concentrations of DL-methionine (DLM) and DL-2-hydroxy-4-methylthiobutanoic acid (DL-HMTBA) in broiler feed was performed to investigate their effect on the meat quality parameters and the shelf life of breast fillet. In total, fillets from 210 male broiler chickens (Ross 308) were tested in seven groups with 30 animals each. Three different concentrations (0.04, 0.12, and 0.32%; on an equimolar basis) of either DLM or DL-HMTBA were added to a basal diet, summing up to seven treatment groups. After slaughter, fillets were packed aerobically and stored at 4°C. The investigated parameters comprised measurements of microbial as well as physicochemical parameters, such as pH, drip loss, cooking loss, and color measurements. Additionally, sensory investigations were conducted and shelf life was calculated. Mean pH values were between 6.1 and 6.4. Drip loss values were low, with mean values below 0.4%. The cooking loss ranged between 22% and 28% on average. The fillets showed a normal initial microbial quality (2.5 log10 cfu/g) and spoilage process with microbial counts of 8.5 log10 cfu/g at the end of storage. The study revealed a significant influence of methionine supplementation on the quality of broiler breast meat in comparison with the basal group. Methionine supplementation led to higher pH values and a higher water binding. Higher concentrations of methionine had a positive influence on the water-holding capacity by lowering the cooking loss. The L∗ value showed a significant negative correlation to the methionine concentration supplemented. No differences in physicochemical as well as sensory parameters could be detected between both methionine sources. The fillets showed a normal sensory spoilage process and a shelf life of 6 d. White striping was positively correlated to fillet weight as well as color values and significantly affected the Purchase Decision, the sensory investigation, and thus the shelf life of the samples.

EFFECT OF PRE-SLAUGHTER CONFINEMENT STRESS ON PHYSICOCHEMICAL PARAMETERS OF CHICKEN MEAT

Abstract The effect of pre-slaughter lairage stress on biogenic amines, pH, and color with the CIELab system (where three variables L*, a*, b* are estimated: L* for lightness, a* defines redness, and b* defines yellowness) in chicken breast meat was investigated. Before slaughtering, 25 broilers were selected and divided into five groups according to lairage holding time (30 min or 3 h), day/night schedule (daylight or nighttime) and control (no lairage). After slaughtering, breasts (M. Pectoralis major) were removed, stored for 9 days at 4 °C, and analyzed every 3 days. The results showed a pH decrease during nighttime holding. Also, a three-hour pre-slaughter holding (daytime or night) resulted in high biogenic amine concentration, increase in lightness (L*), and reduction in redness (a*) during storage. Cadaverine concentration showed a rapid increase from day 6 onward. The time and schedule of chicken lairage is a pre-slaughter stress factor that affects meat quality. Based on these observations, it is recommended to slaughter chickens immediately on arrival at the processing plants.

Effect of different short-term high ambient temperature on chicken meat quality and ultra-structure

Objective

This study investigated the effect of different acute heat stress (HS) levels on chicken meat quality and ultra-structure.

Methods

Chickens were randomly divided into 7 groups to receive different HS treatments: i) 36°C for 1 h, ii) 36°C for 2 h, iii) 38°C for 1 h, iv) 38°C for 2 h, v) 40°C for 1 h, vi) 40°C for 2 h, and vii) un-stressed control group (25°C). Blood cortisol level, breasts initial temperature, color, pH, water holding capacity (WHC), protein solubility and ultra-structure were analyzed.

Results

HS temperatures had significant effects on breast meat temperature, lightness (L*), redness (a*), cooking loss and protein solubility (p<0.05). The HS at 36°C increased L*_{24 h} value (p<0.01) and increased the cooking loss (p<0.05), but decreased a*_{24 h} value (p<0.05). However, as the temperature increased to 38°C and 40°C, all the values of L*_{24 h}, cooking loss and protein denaturation level decreased, and the differences disappeared compared to control group (p> 0.05). Only the ultimate pH_{24 h} at 40°C decreased compared to the control group (p<0.01). The pH in 36°C group declined greater than other heat-stressed group in the first hour postmortem, which contributed breast muscle protein degeneration combining with high body temperature, and these variations reflected on poor meat quality parameters. The muscle fiber integrity level in group 40°C was much better than those in 36°C with the denatured position mainly focused on the interval of muscle fibers which probably contributes WHC and light reflection.

Conclusion

HS at higher temperature (above 38°C) before slaughter did not always lead to more pale and lower WHC breast meat. Breast meat quality parameters had a regression trend as HS temperature raised from 36°C. The interval of muscle fibers at 24 h postmortem and greater pH decline rate with high body temperature in early postmortem period could be a reasonable explanation for the variation of meat quality parameters.

Effect of methionine supplementation in chicken feed on the quality and shelf life of fresh poultry meat

The aim of this study was to investigate the influence of different methionine sources and concentrations on the quality and spoilage process of broiler meat. The trial was comprised of 7 treatment groups: one basal group (suboptimal in Methionine+Cysteine; i.e., 0.89, 0.74, 0.69% in DM SID Met+Cys in starter, grower, and finisher diets, respectively) and 3 doses (0.10, 0.25, and 0.40%) of either DL-Methionine (DLM) or DL-2-hydroxy-4-methylthio butanoic acid (DL-HMTBA) on an equimolar basis of the DLM-supplemented groups. The broilers were fed the diets for 35 d, then slaughtered and processed. The filets were aerobically packed and stored under temperature controlled conditions at 4°C. Meat quality investigations were comprised of microbial investigations (total viable count and Pseudomonas spp.), pH and drip loss measurements of the filets. The shelf life of the meat samples was determined based on sensory parameters. After slaughtering, all supplemented meat samples showed a high quality, whereby no differences between the 2 methionine sources could be detected for the microbial load, pH, and drip loss. In comparison to the control group, the supplemented samples showed a higher sensory quality, characterized by a fresh smell and fresh red color. Methionine supplementation had a significant influence on meat quality parameters during storage. The microbial load, pH and drip loss of the chicken filets were positively correlated to the methionine concentration. Additionally, the microbial load at the end of storage was positively correlated to pH and drip loss values. Nevertheless, the microbial parameters were in a normal range and the positive correlation to methionine concentration did not affect the sensory shelf life. The mean sensory shelf life of the broiler filets varied between 7 to 9 d. During storage, no difference in the development of sensory parameters was observed between the supplemented groups, while the spoilage process of the basal group occurred slightly faster. In conclusion, methionine concentration, but not methionine source, effected meat quality parameters in breast muscles of broilers.

Effect of electrical stunning frequency and current waveform in poultry welfare and meat quality

This study aimed to evaluate the effects of different stunning frequencies and electrical current waveforms on chicken welfare and meat quality. Two-hundred-thirty-two Cobb broilers, 48 d of age and 2.76 ± 0.47 live-weight, were randomly assigned into 4 stunning treatments - 2 frequencies (300 Hz and 650 Hz) and 2 current waveforms (direct current [DC] and alternating current [AC]). Broilers were electrically stunned in a water bath in a commercial slaughterhouse (70 V, 100 mA). The electronarcosis and stunning efficiency were confirmed by assessment of visual parameters (absence of rhythmic breathing, ocular reflex, and coordinated wing flapping) and blood parameters (lactate, glucose, creatine kinase, sodium, and potassium), which were measured after bleeding. The incidence of traumas and injuries was assessed after plucking. Meat quality analysis was performed in Pectoralis major (PM), with determinations of pH, breast yield (PMY), water holding capacity (WHC), water absorption capacity (WAC), thawing loss (DL), cooking loss (CL), shear force (SF), and instrumental color (a*, b*, L*, C*, and h). The interaction between waveform and frequency was significant (P < 0.05) only for lactate, sodium, and lightness (L*). Lactate and sodium levels decreased at 300 Hz-DC. Meat lightness increased at 300 Hz-DC. The individual effect of frequency was significant for glucose, creatine kinase, potassium, WHC, PMY, b*, C*, and h. Regarding waveform, AC decreased plasma glucose and DC decreased creatine kinase and WAC. In general, stunning frequency exerts greater influence than waveform on the welfare and meat quality parameters of broilers. The use of frequency at 650 Hz proved to render animals efficiently unconscious and to promote greater meat quality.

Quality characteristics of broiler chicken meat from free-range and industrial poultry system for the consumers

ABSTRACT

The aim of this study was to determine and compare the quality parameters of broiler chicken meat from free-range and industrial poultry system. Proximate composition, color, pH, shear force, microbial quality and sensory characteristics were evaluated. Both free-range and industrial chicken meat presented PSE (pale, soft and exudative) anomaly (L* > 53). An inverse correlation between lightness, pH and shear force was observed. The free range broiler meat had higher yellow color (b* 11.56) and shear force (2.75 kgf) and lower red color (a* 1.65) and pH (5.75) in comparison to the industrial broiler meat, due intensive physical activity on growing phase and influence of the pre-slaughter stress on the rigor mortis. The thigh cut from free range broiler meat showed higher protein levels (18.00%), while to the thigh and drumstick cuts of industrial broiler meat showed higher total fat levels (3.4 and 5.0%, respectively). In general, each strain and chickens producing methods gave the peculiar characteristics to meat (chemical, physical, microbiological and sensorial).

GRAPHICAL ABSTRACT

Prevalence of pale, soft, and exudative (PSE) condition in chicken meat used for commercial meat processing and its effect on roasted chicken breast

BACKGROUND

Studies on prevalence of pale, soft, exudative (PSE) condition in Sri Lankan poultry industry is minimal. Hence, the objective of present study was to determine the incidence of PSE chicken meat in a commercial meat processing plant and to find out its consequences on meat quality traits of roasted chicken breast.

METHOD

A total of 60 breast fillets were randomly selected, evaluated based on color L* value, and placed into 1 of 2 categories; PSE (L* > 58) or normal meat (L* ≤ 58). A total of 20 breast fillets (10 PSE and 10 normal) were then analyzed for color, pH, and water holding capacity (WHC). After processing those into roasted chicken breast, cooking loss, color, pH, WHC, and texture values were evaluated. A sensory evaluation was conducted using 30 untrained panelists.

RESULTS

The incidence of PSE meat was 70 % in the present experiment. PSE fillets were significantly lighter and had lower pH values compared with normal fillets. Correlation between the lightness and pH was negative (P < 0.05). Although there was no significant difference in color, texture, and WHC values between the 2 groups after processing into roasted chicken breast (P > 0.05), an approximately 3 % higher cooking loss was observed in PSE group compared to its counterpart (P < 0.05). Moreover, cooking loss and lightness values showed a significant positive correlation. Nevertheless, there were no significant differences in sensory parameters between the 2 products (P > 0.05).

CONCLUSIONS

These results indicated that an economical loss can be expected due to the significantly higher cooking loss observed in roasted breast processed from PSE meat.

Monitoring of Chicken RNA Integrity as a Function of Prolonged Postmortem Duration

Gene expression profiling has offered new insights into postmortem molecular changes associated with meat quality. To acquire reliable transcript quantification, high quality RNA is required. The objective of this study was to analyze integrity of RNA isolated from chicken skeletal muscle (pectoralis major) and its capability of serving as the template in quantitative real-time polymerase chain reaction (qPCR) as a function of postmortem intervals representing the end-points of evisceration, carcass chilling and aging stages in chicken abattoirs. Chicken breast muscle was dissected from the carcasses (n = 6) immediately after evisceration, and one-third of each sample was instantly snap-frozen and labeled as 20 min postmortem. The remaining muscle was stored on ice until the next rounds of sample collection (1.5 h and 6 h postmortem). The delayed postmortem duration did not significantly affect A260/A280 and A260/A230 (p≥0.05), suggesting no altered purity of total RNA. Apart from a slight decrease in the 28s:18s ribosomal RNA ratio in 1.5 h samples (p<0.05), the value was not statistically different between 20 min and 6 h samples (p≥0.05), indicating intact total RNA up to 6 h. Abundance of reference genes encoding beta-actin (ACTB), glyceraldehyde 3-phosphate dehydrogenase (GAPDH), hypoxanthine-guanine phosphoribosyltransferase (HPRT), peptidylprolylisomerase A (PPIA) and TATA box-binding protein (TBP) as well as meat-quality associated genes (insulin-like growth factor 1 (IGF1), pyruvate dehydrogenase kinase isozyme 4 (PDK4), and peroxisome proliferator-activated receptor delta (PPARD) were investigated using qPCR. Transcript abundances of ACTB, GAPDH, HPRT, and PPIA were significantly different among all postmortem time points (p<0.05). Transcript levels of PDK4 and PPARD were significantly reduced in the 6 h samples (p<0.05). The findings suggest an adverse effect of a prolonged postmortem duration on reliability of transcript quantification in chicken skeletal muscle. For the best RNA quality, chicken skeletal muscle should be immediately collected after evisceration or within 20 min postmortem, and rapidly preserved by deep freezing.

The effect of replacing inorganic trace minerals with organic Bioplex® and Sel-Plex® on the performance and meat quality of broilers

The aim of this study was to compare the performance and carcass quality of broilers fed diets containing either a commercial inorganic mineral premix (control) or organic trace minerals (OTM) (Sel-Plex® (Se) and Bioplex® copper (Cu), zinc (Zn), manganese (Mn) and iron (Fe)) in a commercial environment. Four identical houses with a total of 119,500 mixed-sex broiler chickens were used (two treatments × two replicates). Birds were fed identical corn/soybean based rations differing only in mineral form and levels. The inorganic treatment (control) provided Cu, Zn, Fe, Mn and Se at levels of 8, 44, 55, 66 and 0.2 ppm, respectively. The OTM contained 5.5, 22, 5.5, 22 and 0.3 ppm of Cu, Zn, Fe, Mn and Se respectively. Growth and feed conversion during the 35-day trial were not influenced (P > 0.05) by treatments. Over the entire trial period and during the first week of production, birds showed significantly lower (P < 0.05) mortality with the OTM treatment. Between 14 and 31 days, sudden death syndrome was lower (P < 0.05) with the OTM diet. OTM improved feathering at 21 days of age (P < 0.001) and lowered carcass skin tearing (P < 0.05). There was no effect of OTM on carcass yield, breast meat pH, drip loss or on meat colour (L* and b* values). However, birds fed organic minerals had redder breast meat (a*) (P < 0.05) on days three and five after slaughter. The results showed that, under commercial conditions, using lower levels of OTM (except Se) in feed relative to inorganic controls can maintain broiler performance.

Propriedades físicas e sensoriais da carne suína PSE

Objetivou-se avaliar as características físicas e sensoriais da carne suína PSE, suas correlações e os prejuízos causados para a indústria, em função de sua ocorrência. Em abatedouro comercial aferiu-se o pH das carcaças (n=1601) aos 45 minutos post mortem (pH45), classificou-as em PSE (pH45<5,8) ou normais (pH45≥5,8). Após 24 horas de resfriamento, foram coletadas amostras do músculo Longissimus dorsi de 26 carcaças PSE e 26 normais, que foram avaliadas quanto à coloração (L*, a*, b*), perda de exsudato, perda de peso por cozimento, força de cisalhamento, atributos sensoriais (maciez, suculência e palatabilidade) e composição centesimal. Foram avaliadas as correlações entre parâmetros físicos e sensoriais. A incidência de carnes PSE foi de 10,06%. O pH final, perda de peso por cozimento, força de cisalhamento e composição centesimal não diferiram entre os tipos de carne. A perda de exsudato foi, aproximadamente, 39% maior para carne PSE. O pH45 correlacionou-se, negativamente, com L* (R= -0,331) e b* (R= -0,528). A suculência correlacionou-se, positivamente, com a palatabilidade (R= 0,436) e maciez (R= 0,297) e, negativamente, com a perda de peso por cozimento (R= -0,326). A força de cisalhamento apresentou correlação positiva com perda de exsudato (R= 0,529) e negativa com maciez (R= -0,767). O prejuízo estimado em função da ocorrência de carnes PSE foi da ordem de R$340.800,00 anuais. Carnes PSE apresentam alterações negativas nas propriedades funcionais e sensoriais, relacionadas com a redução de sua capacidade de retenção de água, o que causa perdas consideráveis para a indústria processadora.