RSS 1.0Food Quality & Sensory Science
In December 2016, Teagasc restructured the Food Research Programme, creating a new department - Food Quality & Sensory Science. The articles in this collection include those authored by members of this department while they were in previous departments.
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Fate of beta-glucan, polyphenols and lipophilic compounds in baked crackers fortified with different barley-milled fractionsFour types of crackers were prepared, whereby wheat flour was substituted with different percentages of barley flour and bran. These formulations were compared to a 100% wheat flour (control) cracker with respect to β-glucan, polyphenols and lipophilic bioactives. Incorporation of barley fractions enriched the β-glucan, and phenolic content, as well as in vitro antioxidant capacities of the crackers. However, some polyphenols including procyanidin C and ferulic acid could not be detected in the crackers owing to the probable degradation of these compounds during baking. The β-glucan, flavanols (catechin and procyanidin B), as well as fatty acids and sterols were least affected; while the α-tocotrienols showed degradation following the baking process. Overall, barley fractions can serve as valued ingredients for enhancing the health-salutary components of fortified crackers or the products thereof.
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Current research and emerging tools to improve fresh red meat qualityA consumer’s decision to purchase red meat is guided by a combination of many interacting factors including safety, nutrition, sustainability and perception of healthiness along with a variety of sensory characteristics such as colour, marbling, tenderness, juiciness and flavour. Red meat quality is complex and influenced by many intrinsic and extrinsic factors, spanning the chain from breed/genetics through to the final end product with key influences coming from on-farm management and post-mortem processing. As a result of various factors, including consumer demands, the importance of both red meat quality and safety has in recent times come to the fore for the meat industry, with steps to meet these requirements having a large bearing on profitability. Therefore, a critical review of steps which can help control these traits is very important. Accordingly, several processing strategies were proposed at the research and industry level aiming to improve fresh red meat quality traits. This review summarises the current methods applied to improve fresh red meat quality and safety, including the advances in management and prediction tools for carcass and technological and sensory quality traits. These methods are also relevant to the safety and microbiological status of carcasses and meat produced, along with the recent developments in sensory analysis, which aim to understand the sensory properties of red meat and consumers responses. The potential of foodomics approaches is discussed under the topics of genomics, proteomics and metabolomics, which help our understanding of the underlying biological mechanisms behind the variation of sensory and technological quality traits and their use for the discovery of putative biomarkers. We further considered the current and emerging sequencing-based methods used to understand microbial community composition of fresh red meat.
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Irish research response to dairy quality in an era of changeThe Irish dairy sector is recognised for its very significant contribution to the national economic status; it is now worth ∼€5 billion annually and represents the largest food and drink export category, which, in turn, represents one of the four largest manufacturing industries in the country. Given anticipated further growth in global demand for dairy products and the positive attributes and capabilities that Ireland has to meet that demand, in terms of pasture-based production and cost competitiveness, it is incumbent for the sector to attain the highest quality milk and dairy products. The combined collaborative approach between research and industry has ensured significant progress and enabled Ireland to remain at the forefront globally in terms of production of quality milk and dairy products. This paper highlights some specific scientific platforms and technologies currently shaping the industry in this regard and discusses current research activity as well as anticipating key requirements for future progress. While research, and farm and processing plant management have accomplished very significant advances in milk and dairy product quality, some overarching emerging challenges include product substitution and sustainability. Some key pillars for the future have been identified on which a strong, efficient dairy sector can be maintained and progressed. Specifically, the use of evidence-based information and real-time measures in prediction and decision-making will be a crucial pillar for the dairy sector of the future. This can promote an approach of proactive maintenance and optimisation of production through improved predictability and control of manufacturing processes.
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Meta-analysis of cheese microbiomes highlights contributions to multiple aspects of qualityA detailed understanding of the cheese microbiome is key to the optimization of flavour, appearance, quality and safety. Accordingly, we conducted a high-resolution meta-analysis of cheese microbiomes and corresponding volatilomes. Using 77 new samples from 55 artisanal cheeses from 27 Irish producers combined with 107 publicly available cheese metagenomes, we recovered 328 metagenome-assembled genomes, including 47 putative new species that could influence taste or colour through the secretion of volatiles or biosynthesis of pigments. Additionally, from a subset of samples, we found that differences in the abundances of strains corresponded with levels of volatiles. Genes encoding bacteriocins and other antimicrobials, such as pseudoalterin, were common, potentially contributing to the control of undesirable microorganisms. Although antibiotic-resistance genes were detected, evidence suggested they are not of major concern with respect to dissemination to other microbiomes. Phages, a potential cause of fermentation failure, were abundant and evidence for phage-mediated gene transfer was detected. The anti-phage defence mechanism CRISPR was widespread and analysis thereof, and of anti-CRISPR proteins, revealed a complex interaction between phages and bacteria. Overall, our results provide new and substantial technological and ecological insights into the cheese microbiome that can be applied to further improve cheese production.
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The Sensory Quality and Volatile Profile of Dark Chocolate Enriched with Encapsulated Probiotic Lactobacillus plantarum BacteriaCocoa and dark chocolate have a wide variety of powerful antioxidants and other nutrients that can positively affect human health. Probiotic dark chocolate has the potential to be a new product in the growing number of functional foods. In this study, encapsulated potential probiotic Lactobacillus plantarum 564 and commercial probiotic Lactobacillus plantarum 299v were added in the production of dark chocolate. The results show very good survival of probiotic bacteria after production and during storage, reaching 108 cfu/g in the first 60 days and over 106 cfu/g up to 180 days. No statistically significant difference (p > 0.05) in chemical composition and no major differences in the volatile profiles between control and experimental chocolate samples were observed, indicating no impact of probiotic bacteria on compositional and sensory characteristics of dark chocolate. The sensory evaluation of control and both probiotic dark chocolate samples showed excellent sensory quality after 60 and 180 days of storage, demonstrating that probiotics did not affect aroma, texture and appearance of chocolate. Due to a high viability of bacterial cells and acceptable sensory properties, it can be concluded that encapsulated probiotics Lb. plantarum 564 and Lb. plantarum 299v could be successfully used in the production of probiotic dark chocolate.
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From Farm to Fork: New Strategies for Quality Evaluation of Fresh Meat and Processed Meat ProductsMeat production has increased globally over the past decades and is expected to keep growing. At the same time, consumers have become more demanding with respect to the quality of meat and meat products. Producing high quality meat consistently is a big challenge for meat producers, processors, and retailers due to the intrinsic variability of the raw material, but it also generates the necessity to develop, improve, and upgrade the current quality analyses by faster and more reliable ones. Precisely, as results of the recent technological and biotechnological advances, a plethora of new possibilities have been opened for the meat production and processing sectors, and a vast improvement of the quality assessment and assurance throughout the whole processing could now be a reality. This special issue aims to cover the recent advances on quality assurance and assessment of fresh meat and meat products.
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Preliminary investigation of the antimicrobial and mechanisms of resistance of Enterobacteria isolated from minced meat in the Northeast of Algeria: The case of butchers from ConstantineFood products of animal origin such as fresh meat are easily contaminated by microorganisms if handling, processing and storage conditions are not fully respected. The present study aimed first to evaluate the bacterial load and microbial contamination rates of ground raw beef to identify the main pathogenic flora that dominate and second, to determine the resistance patterns and extended-spectrum beta-lactamase (ESBL) of isolated Gram-negative strains against certain families of antibiotics. Therefore, 39 samples have been collected from 5 butcher shops located in Constantine province in the North-East of Algeria. The samples were analysed for total bacterial count, presence of total and faecal coliforms, Staphylococci and Salmonella. Furthermore, 23 antibiotics were tested using the diffusion method on Mueller-Hinton agar, towards 22 strains isolates. Bacterial analyses showed a high contamination by total aerobic bacteria, total and faecal coliforms. Escherichia coli, Citrobacter spp., Enterobacter spp., Hafnia alvei, Salmonella pullorum and Staphylococcus spp (except Staphylococcus aureus) were further revealed in some samples. The results of the antibiogram test exhibit multi-resistance to more than eight antibiotics with varied effects. From the whole tested strains isolates, the fully susceptibility effect was for spectinomycin (SPT). This study reveals that the analysed minced meat was found to be highly contaminated with antibiotic resistant bacteria. This study allows concluding that appropriate use of antibiotics in compliance with good hygiene practices is essential to reduce the antibiotic resistance identified in this preliminary study.
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An Overview on Cyclic Fatty Acids as Biomarkers of Quality and Authenticity in the Meat SectorA survey was conducted to determine the content of cyclopropane fatty acids (CPFAs) and ω-cyclohexyl fatty acids (CHFAs) by using gas chromatography- mass spectrometry (GC-MS) and proton nuclear magnetic resonance (1H NMR) techniques in various meat samples from different species, including commercial samples and complex and thermally processed products (i.e., Bolognese sauce). The CPFAs concentration (as the sum of two isomers, namely dihydrosterculic acid and lactobacillic acid) in bovine meat fat (ranging between 70 and 465 mg/kg fat) was positively related to a silage-based diet, and therefore, they are potential biomarkers for monitoring the feeding system of cattle. CHFAs, such as 11-cyclohexylundecanoic and 13-cyclohexyltridecanoic acids, were only found in lipid profiles from ruminant species, and a linear trend was observed in their content, together with iso-branched fatty acids (iso-BCFAs) deriving from ruminal fermentation, as a function of bovine meat percentage in both raw and cooked minced meat. Thus, CHFAs are potential biomarkers for the assurance of the meat species and, combined with iso-BCFAs, of the beef/pork ratio even in complex meat matrices. The proposed approaches are valuable novel tools for meat authentication, which is pivotal in the management of meat quality, safety, and traceability.
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A Cross-Cultural Evaluation of Liking and Perception of Salted Butter Produced from Different Feed SystemsPerception and liking among Irish, German and USA consumers of salted butter produced from different feed systems—outdoor grass (FS-GRSS), grass/clover (FS-CLVR), and indoor concentrate (FS-TMR)—was investigated. A consumer study was conducted in all three countries. Irish and German assessors participated in ranking descriptive analysis (RDA), whereas descriptive analysis (DA) was carried out by a trained panel in the USA. Volatile analysis was conducted to identify differences in aroma compounds related to cow diet. Overall, there was no significant difference in overall liking of the butters, among USA, German and Irish consumers, although cross-cultural preferences were evident. Sensory attribute differences based on cow diet were evident across the three countries, as identified by German and Irish assessors and trained USA panelists, which are likely influenced by familiarity. The abundance of specific volatile aromatic compounds, especially some aldehydes and ketones, were significantly impacted by the feed system and may also contribute to some of the perceived sensory attribute differences in these butters.
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Effect of Cold Plasma on Meat Cholesterol and Lipid OxidationCold atmospheric plasma (CAP) is a novel non-thermal technology with potential applications in inactivating microorganisms in food products. However, its impact on food quality is not yet fully understood. The aim of this research is to study the impact of in-package plasma technology on the stability of cholesterol and total lipid in four different types of meat (beef, pork, lamb and chicken breast). Additionally, any changes in the primary or secondary lipid oxidation, which is undesirable from a health perspective, is investigated. CAP was not found to have any impact on the cholesterol or lipid content. However, higher peroxide and thiobarbituric acid reactive substances (TBARS) values were found for the treated samples, indicating that plasma can induce the acceleration of primary and secondary lipid oxidation. Finally, color was not affected by the treatment supporting the suitability of the technology for meat products.
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The Application of Pureed Butter Beans and a Combination of Inulin and Rebaudioside A for the Replacement of Fat and Sucrose in Sponge Cake: Sensory and Physicochemical AnalysisDetermining minimum levels of fat and sucrose needed for the sensory acceptance of sponge cake while increasing the nutritional quality was the main objective of this study. Sponge cakes with 0, 25, 50 and 75% sucrose replacement (SR) using a combination of inulin and Rebaudioside A (Reb A) were prepared. Sensory acceptance testing (SAT) was carried out on samples. Following experimental results, four more samples were prepared where fat was replaced sequentially (0, 25, 50 and 75%) in sucrose-replaced sponge cakes using pureed butter beans (Pbb) as a replacer. Fat-replaced samples were investigated using sensory (hedonic and intensity) and physicochemical analysis. Texture liking and overall acceptability (OA) were the only hedonic sensory parameters significantly affected after a 50% SR in sponge cake (p < 0.05). A 25% SR had no significant impact on any hedonic sensory properties and samples were just as accepted as the control sucrose sample. A 30% SR was chosen for further experiments. After a 50% fat replacement (FR), no significant differences were found between 30% sucrose-replaced sponge cake samples in relation to all sensory (hedonic and intensity) parameters investigated. Flavour and aroma intensity attributes such as buttery and sweet and, subsequently, liking and OA of samples were negatively affected after a 75% FR (p < 0.05). Instrumental texture properties (hardness and chewiness (N)) did not discriminate between samples with increasing levels of FR using Pbb. Moisture content increased significantly with FR (p < 0.05). A simultaneous reduction in fat (42%) and sucrose was achieved (28%) in sponge cake samples without negatively affecting OA. Optimised samples contained significantly more dietary fibre (p < 0.05).
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The Impact of Terroir on the Flavour of Single Malt Whisk(e)y New Make SpiritThe impact of barley variety and its geographical growth location (environment) on the flavour of new make spirit was investigated to determine if “terroir” can be applied in the production of single malt whisk(e)y. New make spirits were produced at laboratory scale under controlled conditions from two different barley varieties (Olympus and Laureate) grown at two distinct environments (Athy, Co Kildare and Bunclody, Co Wexford) in Ireland over two consecutive seasons (2017 and 2018). The spirit samples were analysed by gas chromatography mass spectrometry olfactometry and descriptive sensory analysis. Forty-two volatiles were detected with eight deemed as very influential and fifteen deemed as influential to the aroma of new make spirit. Sensory attributes were influenced by barley variety, environment, and the interactions thereof over both seasons, with environment and the interaction of variety x environment having a greater impact than variety alone. Chemometric analysis of the olfactometry and sensory data found that both environment and season had a greater impact on the aromatic sensory perception of the new make spirits than variety alone. Therefore, this study clearly demonstrates a “terroir” impact on the flavour of new make spirit and highlights its potential importance especially in relation to single malt whisk(e)y.
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Meat quality characteristics of high dairy genetic-merit Holstein, standard dairy genetic-merit Friesian and Charolais × Holstein-Friesian steersThe increased use of Holstein genetic material in the Irish dairy herd has consequences for beef production. In all, 42 spring-born steers [14 Holsteins (HO), 14 Friesian (FR) and 14 Charolais × Holstein-Friesian (CH)] were reared to slaughter at between 26 and 37 mo of age. Carcass weight was higher and the lipid concentration of m. longissimus thoracis et lumborum was lower (P < 0.05) for CH than the dairy breeds. Overall acceptability tended to be lower (P = 0.055) while tenderness, texture and chewiness were lower (P < 0.05) for CH compared with the dairy breeds. The proportion of C16:1 in the total lipid tended to be lower (P = 0.055) for CH than the dairy breeds. Replacing male offspring of traditional “Irish” Friesian bulls with offspring from a genetically superior (from a dairy perspective) strain of Holstein bull had no commercially important impact on beef nutritional or eating quality.
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Meta-proteomics for the discovery of protein biomarkers of beef tenderness: An overview of integrated studiesThis meta-proteomics review focused on proteins identified as candidate biomarkers of beef tenderness by comparing extreme groups of tenderness using two-dimensional electrophoresis (2-DE) associated with mass spectrometry (MS). We reviewed in this integromics study the results of 12 experiments that identified protein biomarkers from two muscles, Longissimus thoracis (LT) and Semitendinosus (ST), of different types of cattle: young bulls, steers or cows from beef breeds (Charolais, Limousin, Blond d’Aquitaine), hardy breed (Salers) or mixed breed (PDO Maine-Anjou). Comparative proteomics of groups differing in their tenderness evaluated by instrumental Warner-Bratzler shear force (WBSF) or by sensory analysis using trained panelists, revealed 61 proteins differentially abundant (P < 0.05) between tender and tough groups. A higher number of discriminative proteins was observed for LT (50 proteins) compared to ST muscle (28 proteins). The Gene Ontology annotations showed that the proteins of structure and contraction, protection against oxidative stress and apoptosis, energy metabolism, 70 family HSPs and proteasome subunits are more involved in LT tenderness than in ST. Amongst the list of candidate biomarkers of tenderness some proteins such as HSPB1 are common between the 2 muscles whatever the evaluation method of tenderness, but some relationships with tenderness for others (MYH1, TNNT3, HSPB6) are inversed. Muscle specificities were revealed in this meta-proteomic study. For example, Parvalbumin (PVALB) appeared as a robust biomarker in ST muscle whatever the evaluation method of tenderness. HSPA1B seems to be a robust candidate for LT tenderness (with WBSF) regardless the animal type. Some gender specificities were further identified including similarities between cows and steers (MSRA and HSPA9) in contrast to bulls. The comparison of the 12 proteomic studies revealed strong dissimilarities to identify generic biomarkers of beef tenderness. This integrative analysis allowed better understanding of the biological processes involved in tenderness in two muscles and their variations according to the main factors underlying this quality. It allowed also proposing for the first time a comprehensive list of candidate biomarkers to be evaluated deeply to validate their relationships with tenderness on a large number of cattle and breeds.
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Antioxidant active packaging systems to extend the shelf life of sliced cooked hamThe effectiveness of active packaging systems with green tea extract and oregano essential oil was checked for their use in sliced cooked ham. Three packaging systems were evaluated: i) control group without active film, ii) ATGT packed with active film of green tea extract (1%) and iii) ATRX with a mixture of green tea extract and oregano essential oil (1%). The evolution of microbiological, physicochemical (pH, aw, colour and lipid oxidation) and sensory attributes were analysed after 0, 7, 14 and 21 days of refrigerated storage. Microbial populations were below the limits established by the European Regulations (106 UFC/g). The samples packed with ATGT showed the better antimicrobial activity against total viable counts (TVC) and lactic acid bacteria (BAL), while lower counts of Brochothrix thermosphacta was observed in ATRX film (1.48 vs. 1.78 and 2.59 UFC/g for ATRX vs. ATGT and CON, respectively). Regarding colour, low differences were found between the samples packaged with active and control films. Unlike L*, a* and b* parameters showed a progressive diminution throughout the storage in all batches, being the films that contained green tea (ATGT) were the ones that showed the less discolouration at the end of storage (8.86 vs. 8.63 and 7.50 for ATGT vs. CON and ATRX, respectively). The low fat content of this type of product and the use of anaerobic atmosphere for the packaging of cooked ham did not allow to show an antioxidant effect on lipid oxidation (values below 0.15 mg MDA/kg). Finally, the use of ATGT and ATRX did not suppose a modification of the sensorial attributes of the product, being acceptance scores under the acceptance limit during the whole display.
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Dietary Compounds Influencing the Sensorial, Volatile and Phytochemical Properties of Bovine MilkThe main aim of this study was to evaluate the volatile profile, sensory perception, and phytochemical content of bovine milk produced from cows fed on three distinct feeding systems, namely grass (GRS), grass/clover (CLV), and total mixed ration (TMR). Previous studies have identified that feed type can influence the sensory perception of milk directly via the transfer of volatile aromatic compounds, or indirectly by the transfer of non-volatile substrates that act as precursors for volatile compounds. In the present study, significant differences were observed in the phytochemical profile of the different feed and milk samples. The isoflavone formonoetin was significantly higher in CLV feed samples, but higher in raw GRS milk, while other smaller isoflavones, such as daidzein, genistein, and apigenin were highly correlated to raw CLV milk. This suggests that changes in isoflavone content and concentration in milk relate to diet, but also to metabolism in the rumen. This study also found unique potential volatile biomarkers in milk (dimethyl sulfone) related to feeding systems, or significant differences in the concentration of others (toluene, p-cresol, ethyl and methyl esters) based on feeding systems. TMR milk scored significantly higher for hay-like flavor and white color, while GRS and CLV milk scored significantly higher for a creamy color. Milk samples were easily distinguishable by their volatile profile based on feeding system, storage time, and pasteurization.
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Health Benefits of Lactic Acid Bacteria (LAB) FermentatesConsuming fermented foods has been reported to result in improvements in a range of health parameters. These positive effects can be exerted by a combination of the live microorganisms that the fermented foods contain, as well as the bioactive components released into the foods as by-products of the fermentation process. In many instances, and particularly in dairy fermented foods, the microorganisms involved in the fermentation process belong to the lactic acid group of bacteria (LAB). An alternative approach to making some of the health benefits that have been attributed to fermented foods available is through the production of ‘fermentates’. The term ‘fermentate’ generally relates to a powdered preparation, derived from a fermented product and which can contain the fermenting microorganisms, components of these microorganisms, culture supernatants, fermented substrates, and a range of metabolites and bioactive components with potential health benefits. Here, we provide a brief overview of a selection of in vitro and in vivo studies and patents exclusively reporting the health benefits of LAB ‘fermentates’. Typically, in such studies, the potential health benefits have been attributed to the bioactive metabolites present in the crude fermentates and/or culture supernatants rather than the direct effects of the LAB strain(s) involved.
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Influence of high-pressure processing on quality attributes of haddock and mackerel minces during frozen storage, and fishcakes prepared thereofThe study focused on assessing quality parameters of haddock and mackerel minces subjected to a high-pressure treatment (HP) at 200 and 300 MPa and frozen storage at −40 °C. Dry matter, water-holding capacity, protein solubility and oxidation, lipid oxidation, microbiological parameters, low molecular weight metabolites (LMW) and color parameters, were analyzed. The texture of fishcakes prepared on the basis of these fish minces was also studied, showing a decrease in firmness along with an increase in pressure. A marked inhibition of microbial growth was observed in fish minces when increasing the pressure level of HP-treatment. However, no significant effect (p < 0.05) on the content of primary and secondary lipid oxidation products was observed between untreated and 300 MPa-pressurized fish samples. The results suggested that HP-treatment could be successfully applied to both lean and fatty fish samples for reduction of microbial growth with minor changes in product quality. Industrial relevance. The application of high pressure (HP) treatment of 200 and 300 MPa could be successfully applied to both lean and fatty fish species before freezing for reduction of microbial growth. The degree of lipid oxidation is decreasing with an increase in pressure as a result of inactivation of prooxidative endogenous enzymes. Fish minces become slightly lighter and softer after HP-treatment conducted at 200 MPa due to denaturation of proteins, thus enhancing sensory properties of fishcakes prepared thereof.
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What are the drivers of beef sensory quality using metadata of intramuscular connective tissue, fatty acids and muscle fiber characteristics?The aim of this integrative study was to investigate the relationships between biochemical traits (total, insoluble and soluble collagens (TCol, ICol, SCol), cross-links (CLs), proteoglycans (TPGs), proportion of fiber types, total lipids (TLips), main fatty acids (FAs) families, the n-6/n-3 polyunsaturated FA (n-6/n-3PUFA) ratio and the sensory attributes scores (tenderness, juiciness, flavor) of two muscles from beef: Rectus abdominis (RA) and Longissimus thoracis (LT). For robust analysis, a database was prepared using samples from three studies from animals raised under different production systems. The analyses were performed either on each study separately or on pooled data per muscle after removing as many experimental effects as possible in each study. The CLs (across the muscles and studies) and, to a lower extent, type IIA muscle fibers (mainly for RA muscles), saturated FAs (SFAs), monounsaturated FAs (MUFAs) (for the LT muscles) were the components the most frequently associated with tenderness. The CLs, type IIA muscle fibers (mainly for the RA muscles), TLips, SFAs, MUFAs, conjugated linoleic acids (CLAs) and n-6/n-3 PUFA ratio (mainly for the LT muscles) were the components the most associated with juiciness. The TLips and CLAs (across the muscles and studies), SFAs, MUFAs (mainly for the LT muscles), CLs (mainly for the RA muscles) and TPGs (mainly for the LT muscles) were the components the most associated with flavor liking. The CLs, CLAs, TLips, SFAs, MUFAs, n-6/n-3 PUFA ratio, type IIA and I muscle fibers were the components the most frequently associated with the 3 sensory scores taken together. The SCol, TPGs and type IIX+B muscle fibers were little associated with the sensory scores taken together. The TCol, ICol and PUFAs were components the least associated with sensory scores. The data of this integrative study highlighted for the first time that the CLs were negatively involved in the determination of the three sensory traits mainly in the RA muscle. The muscle fibers in this integrative study had a weak impact on the variations in beef sensory traits. The type IIA and IIX+B muscle fibers were respectively negatively and positively associated with tenderness, negatively associated with juiciness and flavor. The type I muscle fibers were overall positively associated with juiciness and flavor and negatively or positively with tenderness and these associations were muscle and study-dependent. Overall, the TLips and FAs were positively associated with the sensory scores and the n-6/n-3 PUFA ratio was negatively associated with them.
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Influence of particle size on the physicochemical properties and stickiness of dairy powdersThe compositional and physicochemical properties of different whey permeate (WPP), demineralised whey (DWP) and skim milk powder (SMP) size fractions were investigated. Bulk composition of WPP and DWP was significantly (P < 0.05) influenced by powder particle size; smaller particles had higher protein and lower lactose contents. Microscopic observations showed that WPP and DWP contained both larger lactose crystals and smaller amorphous particles. Bulk composition of SMP did not vary with particle size. Surface composition of the smallest SMP fraction (<75 μm) showed significantly lower protein (−9%) and higher fat (+5%) coverage compared with non-fractionated powders. For all powders, smaller particles were more susceptible to sticking. Hygroscopicity of SMP was not affected by particle size; hygroscopicity of semi-crystalline powders was inversely related to particle size. This study provides insights into differences between size fractions of dairy powders, which can potentially impact the sticking/caking behaviour of fine particles during processing.
