Effect of pH and postmortem aging on protein extraction from broiler breast muscle

Lysine Depletion during Different Feeding Phases: Effects on Growth Performances and Meat Quality of Broiler Chickens

Simple Summary

In the past, many studies have been carried out to investigate the effect of lysine supplementation on broilers’ growth performances and feed efficiency. However, the knowledge concerning the reduction of the dietary content of this essential amino acid is limited and mainly restricted to the production performances of the birds. Within this context, the present study aimed at assessing the impact of lysine restriction during grower I (10–20 d) and grower I and II (10–20 and 21–34 d) feeding phases on live performances, breast meat quality traits and technological properties, as well as on the incidence and severity of abnormalities affecting the pectoral muscles (i.e., white striping, wooden breast and spaghetti meat). Lysine restriction during different feeding phases exerts negligible effects on the production performances of the broilers due to their compensatory growth. In addition, the increased anserine content following lysine depletion might have exerted a protective role against protein denaturation by buffering the acidic end-products generated during post-mortem rigor development.

Abstract

The present study aimed at assessing the impact of lysine restriction performed during different feeding phases on growth performances, meat quality traits and technological properties as well as on the incidence and severity of breast muscle abnormalities. For this purpose, a total of 945 one-day-old Ross 308 male chicks was randomly divided into three experimental groups: CONT, fed a four feeding phases commercial diet, GRW I, and GRW I + II fed CONT diet with the depletion of synthetic lysine during grower I and grower I and II feeding phases, respectively. Productive performances were recorded throughout the whole rearing cycle and the incidence of breast muscle growth-related abnormalities assessed at slaughter (49 d) on 280 breasts/group. Quality traits and technological properties of breast meat were measured on a total of 54 Pectoralis major muscles. Lysine restriction only marginally affected the productive performances and the quality parameters of breast meat. The increased (p < 0.05) solubility of the protein fraction along with the remarkably higher (p < 0.05) anserine content found in GRW I + II suggests an increased energy requirement in the pectoral muscles belonging to lysine-restricted birds and supports the hypothesis of a reduced protein synthesis taking place within these muscles.

Impact of Extraction Method on the Detection of Quality Biomarkers in Normal vs. DFD Meat

The objective of this work was to demonstrate how the extraction method affects the reliability of biomarker detection and how this detection depends on the biomarker location within the cell compartment. Different extraction methods were used to study the sarcoplasmic and myofibrillar fractions of the Longissimus thoracis et lumborum muscle of young bulls of the Asturiana de los Valles breed in two quality grades, standard (Control) or dark, firm, and dry (DFD) meat. Protein extractability and the expression of some of the main meat quality biomarkers—oxidative status (lipoperoxidation (LPO) and catalase activity (CAT)), proteome (SDS-PAGE electrophoretic pattern), and cell stress protein (Hsp70)—were analyzed. In the sarcoplasmic fraction, buffers containing Triton X-100 showed significantly higher protein extractability, LPO, and higher intensity of high-molecular-weight protein bands, whereas the TES buffer was more sensitive to distinguishing differences in the protein pattern between the Control and DFD meat. In the myofibrillar fraction, samples extracted with the lysis buffer showed significantly higher protein extractability, whereas samples extracted with the non-denaturing buffer showed higher results for LPO, CAT, and Hsp70, and higher-intensity bands in the electrophoretic pattern. These findings highlight the need for the careful selection of the extraction method used to analyze the different biomarkers considering their cellular location to adapt the extractive process.

Antiglycating Effect of Phenolics from the Chilean Currant Ribes cucullatum under Thermal Treatment

Numerous dietary polyphenols possess antiglicating activity, but the effects of thermal treatment on this activity are mostly unknown. The effect of thermal treatment in the antiglycating activity of polyphenolic enriched extracts (PEEs) from Ribes cucullatum towards glyoxal-induced glycation of sarcoplasmic proteins was assessed. Sarcoplasmic proteins from chicken, beef, salmon, and turkey, were incubated 2 h at 60 °C with and without glyoxal and different concentrations of PEEs (0.25, 0.5, 1, and 5 mg/mL). The antiglycating activity was evaluated by: (1) Lys and Arg consumption, (2) Carboxymethyl lysine (CML) generation, and (3) lipid-derived electrophiles inhibition in a gastric digestion model. Protective effects were observed against CML generation in proteins and a decrease of electrophiles in the gastric digestion model. A dose-dependent consumption of Lys and Arg in proteins/PEEs samples, indicated the possible occurrence of quinoproteins generation from the phenolics. Protein/PEEs incubations were assessed by: (1) High pressure liquid chromatography analysis, (2) Gel electrophoresis (SDS-PAGE), and (3) Redox cycling staining of quinoproteins. Protein/PEEs incubations produced: (1) Decrease in phenolics, (2) increase of protein crosslinking, and (3) dose-dependent generation of quinoproteins. We demonstrate that phenolic compounds from R. cucullatum under thermal treatment act as antiglycating agents, but oxidative reactions occurs at high concentrations, generating protein crosslinking and quinoproteins.

Early Postmortem Proteome Changes in Normal and Woody Broiler Breast Muscles

Early postmortem changes in the whole muscle proteome from normal broiler (NB) and woody broiler (WB) breasts at 0 min, 15 min, 4 h, and 24 h after slaughter were analyzed using two-dimensional gel electrophoresis (2DE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Elongation factor 2, EH domain-containing protein 2, phosphoglycerate mutase 1 (PGAM1), and T-complex protein 1 subunit gamma were differentially abundant in both NB and WB muscles during the early postmortem storage. Twenty additional proteins were differentially abundant among four postmortem time points in either NB or WB muscles. In the postmortem WB, changes in protein degradation were observed, including the degradation of desmin fragments, ovotransferrin chain A, and troponin I chain I. Additionally, a few glycolytic proteins in the WB might have undergone post-translational modification, including enolase, phosphoglucomutase-1, PGAM1, and pyruvate kinase. These changes in protein biomarkers highlight the impact of WB myopathy on postmortem proteome changes and increase our understanding of the relationship between WB conditions, postmortem biochemistry, and meat quality.

Interactions between beef salt-soluble proteins and elephant foot yam (Amorphophallus campanulatus) flour in heat-induced gel matrix development

The objective of this study was to observe the interactions between salt-soluble proteins extracted from beef and elephant foot yam (Amorphophallus campanulatus) flour in heat-induced gel matrix development. The effect of salt concentration; 0.5%, 1.0%, 1.5%, and 2.0% in weight/weight basis (w/w), during protein extraction on pH, salt-soluble protein concentration and myofibril fractions of beef extract was determined firstly, and no significant effect was found. The beef salt-soluble proteins extracted using salt solution at different concentrations were then added with elephant foot yam flour at 5%, 10%, and 15% w/w, gelatinized at 90°C for 20 min, and cooled down at 4°C for 12 h. The interactions between beef salt-soluble proteins and elephant foot yam flour resulted in an improved gel strength (p < 0.01) and the addition level of elephant foot yam flour affected the pH, instrumental color, moisture, crude protein, and ash content significantly. The addition of elephant foot yam flour also reduced the size of the pores in the gel matrix as shown by scanning electron microscope (SEM) photographs. These suggest that elephant foot yam flour well interacts with beef salt-soluble proteins to form gel matrix.

Methods for Extraction of Muscle Proteins from Meat and Fish Using Denaturing and Nondenaturing Solutions

The objective of the present study was to test two extraction methods including solutions with different ionic strengths on the extraction and separation of the myofibrillar proteins from meat and fish muscles of different species. Meat samples from longissimus thoracis muscle of beef and lamb, pectoralis major muscle of chicken, and dorsal white muscle of fish from sole (Solea solea), European hake (Merluccius merluccius), and sea bass (Dicentrarchus labrax) were analyzed. The extraction method using nondenaturing solution led to a major extraction of high molecular-weight proteins as myosin heavy chain, α-actinin, and desmin; on the contrary, the denaturing method provided a good protein extractability of proteins and fragments with low molecular-weight as actin, troponin-T, tropomyosin, and myosin light chain 1 and 2 proteins for the most meat and fish samples. The nondenaturing extraction method showed several advantages resulting in time and labour saving and in minimizing the use of toxic and polluting agents.

Functional and Film-forming Properties of Mechanically Deboned Chicken Meat Proteins

In the present study, the functional properties of mechanically deboned chicken meat proteins (MDCM-Ps) were determined at different pH (2, 4, 6, 8 and 12), and film-forming properties were evaluated depending on MDCM-P (2, 3 and 4 %) and glycerol (30, 40 and 50 %) concentrations. The highest solubility, emulsifying and foaming properties were determined at pH 12. MDCM-P solutions showed non-polyelectrolyte behavior and gelation onset temperature was determined at 36 °C. Film-forming properties of MDCM-P showed that the tensile strength decreased, and elongation at break increased as glycerol concentration increased. Films became more transparent with increasing glycerol and decreasing protein concentration, while water vapor permeability increased with increasing glycerol and protein concentration. Water sorption data of films were fitted to the Guggenheim, Anderson, and De Boer model. In general, equilibrium moisture content of films increased as glycerol level increased. Overall, the results showed that MDCM-P could be useful as a new protein source for both food and packaging industries.

Marination and Physicochemical Characteristics of Vacuum-aged Duck Breast Meat

We investigated marinade absorption and physicochemical characteristics of vacuum-aged duck breasts that were halved and individually vacuum-packed for chiller aging at 4°C for 14 d. One half was marinated for 0, 7, or 14 d, while the second half was used as a control. Marinade absorption, cooking loss, cooking yield, texture profile, pH, color, protein solubility, and thiobarbituric acid reactive substances (TBARS) values were evaluated, and protein sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was performed. Marinade absorption and pH did not vary significantly after 14 d of aging. Marination increased the pH, color (a* and b*) values, and cooking yield and reduced cooking loss. TBARS values significantly increased with aging time, but were significantly reduced by marination. Myofibril and total protein solubility increased with aging and marination, while SDS-PAGE showed protein degradation. Hence, aging and marination can be used simultaneously to improve physicochemical quality and cooking yield of vacuum-aged duck breast.