A comparative study of chemical composition, color, and thermal gelling properties of normal and PSE-like chicken breast meat

Nano Filling Effect of Nonmeat Protein Emulsion on the Rheological Property of Myofibrillar Protein Gel

Incorporation of vegetable oils through pre-emulsification has received notable attention for delivering polyunsaturated fatty acids to emulsified-type meat products. The two important influencing factors of the rheological property of composite myofibrillar protein (MP) gel are emulsion droplet size and active or inactive interaction between interface and meat proteins. Incorporation of nonmeat protein emulsion (2% protein (w/w), egg-white protein isolate (EPI), porcine plasma protein (PPP), or sodium caseinate (SC)) with different droplet sizes (nano or macro) to a model of 2% MP gel was investigated in this research. The results of drop size measurement showed that 15,000 psi homogenizing could decrease the diameter of emulsion drop from macro- to nanoscale in the range of 324.4−734.5 nm. Active fillers (PPP and EPI emulsions) with nanodroplet size did not influence the viscosity of emulsion-filled composite cold sols but caused positive filling effects on the MP gel matrix after heating, as evidenced by the density microstructure. PPP and EPI nano-emulsion-filled composite MP had a significant high storage modulus enforcement effect, which reached nearly eight times those of other treatments (p < 0.05). Similarly, the results of thermal scanning rheology and a large-deformation mechanical test showed that PPP and EPI emulsions with nanoscale droplets, other than macroscale, had the highest gel strength of heat-induced emulsion-filled composite MP gel (p < 0.05). Overall, these findings will be helpful for selecting the correct pre-emulsified protein and designing the textural properties of foods.

Compositional Differences Among Types of Mechanically Separated Chicken and Their Influence on Physicochemical Attributes of Frankfurter-Type Sausages

Mechanically separated chicken (MSC) from 2 different separation methods (MSC1, Beehive separator, aged bones [Provisur Technologies, Mokena, IL]; MSC2, Poss separator, fresh bones [Poss Design Limited, Oakville, Ontario, Canada]) and chicken breast trim (CBT) were used as raw materials in frankfurters. Texture, color, and lipid oxidation were measured over a refrigerated storage period of 98 d. Both MSC were higher in fat and lower in moisture than CBT. MSC frankfurters had lower L* and higher a* values than CBT frankfurters, with MSC2 frankfurters having the lowest L* and highest a* (P &lt; 0.05). Thiobarbituric acid-reactive substances values were higher in MSC1 frankfurters (P &lt; 0.05) than in CBT and MSC2 frankfurters. Texture Profile Analysis hardness, cohesiveness, resilience, and chewiness were highest in MSC2 frankfurters. Differences among MSC resulted in detectable differences in finished product attributes, with MSC2 frankfurters being darker and redder and having lower levels of lipid oxidation than MSC1 frankfurters, underscoring the importance of understanding the specific functional attributes of MSC obtained by different processes prior to product formulation and manufacturing.

Prediction of quality traits and grades of intact chicken breast fillets by hyperspectral imaging

1. In this study, hyperspectral imaging was evaluated for its usefulness to predict quality traits and grading of intact chicken breast fillets. 2. Lightness of colour (L*) and pH of the fillets were measured as quality traits, and samples were then selected and graded to three different quality categories, i.e., dark, firm and dry (DFD), normal (NORM), and pale, soft and exudative (PSE) based on these two quality traits. Based on the prediction performance of full wavelength partial least square regression (PLSR) models, the spectral range of visible and near-infrared (Vis-NIR) was more suitable for the evaluation of quality traits and grading than the range of near-infrared (NIR). Key wavelengths of each quality trait and grade value were selected by the regression coefficient (RC) method. 3. The new key wavelength PLSR models showed good predictive performances (Rp = 0.85 and RMSEp = 2.18 for L*, Rp = 0.84, and RMSEp = 0.13 for pH, and Rp = 0.80 and RMSEp = 0.44 for quality grading). The classification accuracy for grades was 85.71% (calibration set) and 81.82% (prediction set), respectively. Finally, distribution maps showed that quality traits and grades of samples were able to be visualised. 4. These results suggested that hyperspectral imaging has the potential for quality prediction of fresh chicken meat.

Effect of wooden breast myopathy on water-holding capacity and rheological and gelling properties of chicken broiler breast batters

The objective of this study was to evaluate the effects of wooden breast myopathy on water-holding, rheological, and gelling properties of chicken broiler breast batter. As to water-holding capacity, wooden breast myopathy significantly increased cooking loss and thawing loss of meat batter compared with that of a normal sample (P < 0.05). With regard to rheological properties, the viscosity, storage modulus, and loss modulus of meat batter gradually reduced as wooden breast myopathy worsened. Similarly, lightness, hardness, gumminess, and chewiness of heat-induced meat gels reduced with wooden breast myopathy worsening. Severe wooden breast myopathy significantly reduced lightness, hardness, gumminess, and chewiness of heat-induced meat gels (P < 0.05). Water distribution of heat-induced meat gels showed that the relaxation times of T_2b1, T_2b2, and T₂₁ generally increased, whereas T₂₂ gradually decreased when wooden breast myopathy worsened. The corresponding proportions (P_2b1, P_2b2, and P₂₁) of T₂ populations (T_2b and T₂₁) generally decreased, and the P₂₂ gradually increased. Severe wooden breast myopathy significantly reduced the relaxation time of T₂₂ and increased proportion (P₂₂) of T₂₂ peak (P < 0.05), but no significant difference was found in immobilized water of heat-induced meat gels. The light microscopy revealed the looser structure of gels with many big bubbles in wooden breast groups when compared with that of normal breast heat-induced gels. It is concluded that the incidence of wooden breast myopathy worsens water-holding capacity and rheological and gelling properties of breast batter of chicken broiler, reducing the further processing property.

Comparative study of thermal gelation properties and molecular forces of actomyosin extracted from normal and pale, soft and exudative-like chicken breast meat

OBJECTIVE

The objectives of this study were to investigate the thermal gelation properties and molecular forces of actomyosin extracted from two classes of chicken breast meat qualities (normal and pale, soft and exudative [PSE]-like) during heating process to further improve the understanding of the variations of functional properties between normal and PSE-like chicken breast meat.

METHODS

Actomyosin was extracted from normal and PSE-like chicken breast meat and the gel strength, water-holding capacity (WHC), protein loss, particle size and distribution, dynamic rheology and protein thermal stability were determined, then turbidity, active sulfhydryl group contents, hydrophobicity and molecular forces during thermal-induced gelling formation were comparatively studied.

RESULTS

Sodium dodecyl sulphate-polyacrylamide gel electrophoresis showed that protein profiles of actomyosin extracted from normal and PSE-like meat were not significantly different (p>0.05). Compared with normal actomyosin, PSE-like actomyosin had lower gel strength, WHC, particle size, less protein content involved in thermal gelation forming (p<0.05), and reduced onset temperature (To), thermal transition temperature (Td), storage modulus (G') and loss modulus (G″). The turbidity, reactive sulfhydryl group of PSE-like actomyosin were higher when heated from 40°C to 60°C. Further heating to 80°C had lower transition from reactive sulfhydryl group into a disulfide bond and surface hydrophobicity. Molecular forces showed that hydrophobic interaction was the main force for heat-induced gel formation while both ionic and hydrogen bonds were different significantly between normal and PSE-like actomyosin (p<0.05).

CONCLUSION

These changes in chemical groups and inter-molecular bonds affected protein-protein interaction and protein-water interaction and contributed to the inferior thermal gelation properties of PSE-like meat.

Further insight into the role of Ca2+ in broiler pale, soft and exudative-like (PSE) meat through the analysis of moisture by TGA and strong cation elements by ICP-OES

This study evaluated moisture content of broiler breast PSE meat by thermal gravimetric analysis and strong cation elements by inductively coupled plasma optical emission spectrometry. The weight changes were monitored within the temperature interval 9-750 °C and the most severe changes were observed at 9-160 °C (1A). This remarkable transition was attributed to water loss of about 64.74% in normal samples while PSE samples lost about 61.16%. There was, therefore, approximately 4.0% lower moisture in PSE meat samples in relation to normal meat. The analysis of cation elements showed significant differences (p < 0.05), with normal samples having 13.0% higher ∑[Ca²⁺] + [Mg²⁺] + [Na⁺]+[K⁺] than PSE meat samples while [Ca²⁺] in PSE meat was 10.81% higher than in the normal counterparts. We provided further evidence of the role of Ca²⁺ excess within the muscle sarcomere during the onset of PSE meat.