The Use of Potassium Chloride and Tapioca Starch to Enhance the Flavour and Texture of Phosphate- and Sodium-Reduced Low Fat Breakfast Sausages Manufactured Using High Pressure-Treated Meat.

The objective of this study was to investigate the use of potassium chloride (KCl) and tapioca starch (TS) to reduce salt levels below 1.5% in sausages manufactured using previously high pressure (HP) processed pork (150 MPa). A 3 × 2 × 1 factorial design was used to formulate breakfast sausages with three salt levels (0.5%, 1.0%, and 1.5%), two ingredient levels (no added ingredient or added as a combination of KCl\TS), and one pressure level (150 MPa). Partial replacement of NaCl with KCl and addition of TS had beneficial effects on the water binding abilities of sausage batters by decreasing (p < 0.05) total expressible fluid (%) and increasing water holding capacity (%). Overall, results indicated that the use of KCl\TS imparted some beneficial effects to salt-reduced low fat breakfast sausages and has the potential to reduce salt levels in the breakfast sausages to 1.0% while still maintaining the organoleptic and functional properties traditionally associated with these meat products.

Optimization of textural and technological parameters using response surface methodology for the development of beef products for older consumers.

Red meat has a tougher texture compared with many other food products, therefore consumption is often reduced among older adults. Acidic treatments had a positive effect on WBSF values (reduced the WBSF values from 23.35 N for control to 14.83 N), and texture parameters and a combination with apple fiber and rice starch may improve the health profile of a meat product with benefits for consumers, particularly for older population. A novel meat product with a softer texture (apple fiber 0.15%, rice starch 0.30% and citric acid 0.16 M) was optimized and successfully validated in this study. The results obtained for the objective measurements of tenderness were confirmed by consumers' tenderness results (p < .05) moreover texture-optimized beef samples were found to be more acceptable by older consumers compared with control. Meat processors have an important role in increasing the availability of suitable meat products for older consumers, by developing products that will meet their nutritional and textural needs. In this study, a novel meat product with a softer texture was developed, successfully validated and the product was found to be acceptable by older consumers. Meat processors could consider using rice starch, apple fiber, and citric acid as feasible alternative to traditional ingredients used for beef injection, in order to obtain a softer product, that appeal to older consumers with difficulties in mastication.

The Collagen Suprafamily: From Biosynthesis to Advanced Biomaterial Development.

Collagen is the oldest and most abundant extracellular matrix protein that has found many applications in food, cosmetic, pharmaceutical, and biomedical industries. First, an overview of the family of collagens and their respective structures, conformation, and biosynthesis is provided. The advances and shortfalls of various collagen preparations (e.g., mammalian/marine extracted collagen, cell-produced collagens, recombinant collagens, and collagen-like peptides) and crosslinking technologies (e.g., chemical, physical, and biological) are then critically discussed. Subsequently, an array of structural, thermal, mechanical, biochemical, and biological assays is examined, which are developed to analyze and characterize collagenous structures. Lastly, a comprehensive review is provided on how advances in engineering, chemistry, and biology have enabled the development of bioactive, 3D structures (e.g., tissue grafts, biomaterials, cell-assembled tissue equivalents) that closely imitate native supramolecular assemblies and have the capacity to deliver in a localized and sustained manner viable cell populations and/or bioactive/therapeutic molecules. Clearly, collagens have a long history in both evolution and biotechnology and continue to offer both challenges and exciting opportunities in regenerative medicine as nature's biomaterial of choice.

The application of high-pressure treatment in the reduction of salt levels in reduced-phosphate breakfast sausages.

This study investigated the effects of high pressure (HP) treatment of pork meat before manufacturing sausages with reduced salt levels and compared them to sausages manufactured with untreated meat (control sausages). A 2×5 factorial design was set up incorporating two pressure levels (0 or 150 MPa) and five salt levels (0.5, 1.0, 1.5, 2.0 and 2.5%). Most quality attributes were affected when salt levels were reduced below 1.5%. Fat loss (FL) was (P<0.05) affected by salt level; samples with <1.5% salt had the highest FL. HP treatment increased emulsion stability and reduced cook loss (CL) compared to control sausages. Increased CL was observed when salt was reduced below 2.0%. Salt reduction below 1.5% adversely affected colour, sensory and texture attributes. Independent of salt, HP treatment affected adversely juiciness and cohesiveness while adhesiveness was improved. Overall, there is potential to manufacture sausages maintaining organoleptic and functional properties traditionally associated with sausages using HP treated meat.

Transcriptome analysis of porcine M. semimembranosus divergent in intramuscular fat as a consequence of dietary protein restriction.

BACKGROUND: Intramuscular fat (IMF) content is positively correlated with aspects of pork palatability, including flavour, juiciness and overall acceptability. The ratio of energy to protein in the finishing diet of growing pigs can impact on IMF content with consequences for pork quality. The objective of this study was to compare gene expression profiles of Musculus semimembranosus (SM) of animals divergent for IMF as a consequence of protein dietary restriction in an isocaloric diet. The animal model was derived through the imposition of low or high protein diets during the finisher stage in Duroc gilts. RNA was extracted from post mortem SM tissue, processed and hybridised to Affymetrix porcine GeneChip® arrays. RESULTS: IMF content of SM muscle was increased on the low protein diet (3.60 ± 0.38% versus 1.92 ± 0.35%). Backfat depth was also greater in animals on the low protein diet, and average daily gain and feed conversion ratio were lower, but muscle depth, protein content and moisture content were not affected. A total of 542 annotated genes were differentially expressed (DE) between animals on low and high protein diets, with 351 down-regulated and 191 up-regulated on the low protein diet. Transcript differences were validated for a subset of DE genes by qPCR. Alterations in functions related to cell cycle, muscle growth, extracellular matrix organisation, collagen development, lipogenesis and lipolysis, were observed. Expression of adipokines including LEP, TNFα and HIF1α were increased and the hypoxic stress response was induced. Many of the identified transcriptomic responses have also been observed in genetic and fetal programming models of differential IMF accumulation, indicating they may be robust biological indicators of IMF content. CONCLUSION: An extensive perturbation of overall energy metabolism in muscle occurs in response to protein restriction. A low protein diet can modulate IMF content of the SM by altering gene pathways involved in lipid biosynthesis and degradation; however this nutritional challenge negatively impacts protein synthesis pathways, with potential consequences for growth.

SNP variation in the promoter of the PRKAG3 gene and association with meat quality traits in pig.

BACKGROUND: The PRKAG3 gene encodes the γ3 subunit of adenosine monophosphate activated protein kinase (AMPK), a protein that plays a key role in energy metabolism in skeletal muscle. Non-synonymous single nucleotide polymorphisms (SNPs) in this gene such as I199V are associated with important pork quality traits. The objective of this study was to investigate the relationship between gene expression of the PRKAG3 gene, SNP variation in the PRKAG3 promoter and meat quality phenotypes in pork. RESULTS: PRKAG3 gene expression was found to correlate with a number of traits relating to glycolytic potential (GP) and intramuscular fat (IMF) in three phenotypically diverse F1 crosses comprising of 31 Large White, 23 Duroc and 32 Pietrain sire breeds. The majority of associations were observed in the Large White cross. There was a significant association between genotype at the g.-311A>G locus and PRKAG3 gene expression in the Large White cross. In the same population, ten novel SNPs were identified within a 1.3 kb region spanning the promoter and from this three major haplotypes were inferred. Two tagging SNPs (g.-995A>G and g.-311A>G) characterised the haplotypes within the promoter region being studied. These two SNPs were subsequently genotyped in larger populations consisting of Large White (n = 98), Duroc (n = 99) and Pietrain (n = 98) purebreds. Four major haplotypes including promoter SNP's g.-995A>G and g.-311A>G and I199V were inferred. In the Large White breed, HAP1 was associated with IMF% in the M. longissmus thoracis et lumborum (LTL) and driploss%. HAP2 was associated with IMFL% GP-influenced traits pH at 24 hr in LTL (pHULT), pH at 45 min in LTL (pH(45)LT) and pH at 45 min in the M. semimembranosus muscle (pH(45)SM). HAP3 was associated with driploss%, pHULT pH(45)LT and b* Minolta. In the Duroc breed, associations were observed between HAP1 and driploss% and pHUSM. No associations were observed with the remaining haplotypes (HAP2, HAP3 and HAP4) in the Duroc breed. The Pietrain breed was monomorphic in the promoter region. The I199V locus was associated with several GP-influenced traits across all three breeds and IMF% in the Large White and Pietrain breed. No significant difference in promoter function was observed for the three main promoter haplotypes when tested in vitro. CONCLUSION: Gene expression levels of the porcine PRKAG3 are associated with meat quality phenotypes relating to glycolytic potential and IMF% in the Large White breed, while SNP variation in the promoter region of the gene is associated with PRKAG3 gene expression and meat quality phenotypes.

Association between promoter polymorphisms in a key cytoskeletal gene (Ankyrin 1) and intramuscular fat and water-holding capacity in porcine muscle.

Ankyrin 1 (ANK1) is a positional and functional candidate gene for both bovine and porcine meat quality. The objectives of this study were: (1) to determine if the gene expression levels of ANK1 are associated with pig meat quality traits; (2) to examine polymorphisms in the promoter region of the porcine ANK1 gene for association with meat quality in diverse breeds; and (3) to search for putative transcription factor binding sites predicted to be altered by such polymorphisms. ANK1 gene expression was positively correlated with drip loss (%) in the Large White breed. Twelve novel SNPs were discovered in a 761 bp region of the ANK1 promoter in three phenotypically diverse F1 cross populations. Five were subsequently selected for association analysis with meat quality traits and genotyped in three pure pig breeds (Pietrain n = 98, Duroc n = 99 and Large White n = 98). Two of these five SNPs were associated with meat quality traits at the Bonferroni significance threshold: g.-606G>A with drip loss % in the Pietrain breed and g.-272G>A with intramuscular fat (IMF) in the LTL and SM. Following haplotype construction from SNP genotypes, Haplotype 3 was found to be associated with drip loss % at the Bonferroni level of significance in the Pietrain breed and Haplotype 5 was associated at the Bonferroni level with IMF in two muscles in the Large White breed. Further associations were observed at the nominal significance threshold. Our conclusion from this study is that SNPs in the ANK1 gene promoter could potentially contribute to genome-assisted selection SNP panels to improve IMF and water holding capacity on a breed basis.

Influence of HPP conditions on selected beef quality attributes and their stability during chilled storage.

The aim of this work was to determine the effects of combined pressure and temperature treatments on beef quality attributes after processing and during chilled storage. Beef M. pectoralis profundus samples were pressurised at 400 and 600 MPa at 35, 45 and 55°C and compared with non-treated (NT) and oven cooked samples. High pressure processing (HPP) at higher temperatures (55°C) resulted in lower Warner Bratzler Shear Force (WBSF) and cook loss values than processing at 35°C. Thiobarbituric acid reactive substances (TBARS) values of pressurised samples were lower than cooked samples after processing and throughout refrigerated storage. An increase (p<0.001) in the omega 6/omega 3 (n6/n3) fatty acid ratio was found when pressure-temperature treatments were compared to raw samples, however, oven cooked samples presented the highest n6/n3 ratio among all of the treatments examined. The reported results show that HPP alters meat quality to a lesser extent than conventional cooking, thereby minimising the processing impact.