Food and Nutritional Sciences - Doctoral Theses
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Item Evidence-based design, physiological efficacy testing and consumer analysis of an exemplar model of a fruit derived bioactive functional food for use in physical performance and exercise settings(University College Cork, 2023) Carey, Conor C.; Lucey, Alice; Doyle, Lorna; Department of Agriculture, Food and the Marine, IrelandThe overall aim of this thesis is to examine the new product development practices used within the scientific design, development and testing of new nutritional products in the performance nutrition sector. Despite recent growth in the area there is a general lack of publicly available information to guide the incorporation of nutritional science into the processes underpinning the design and development of new performance nutritional products. Performance nutrition provides a promising area for the creation of value-add products using Irish agrifood outputs, a key priority in Irelands Food Vision 2030 strategy (Gov.ie - Food Vision 2030 – A World Leader in Sustainable Food Systems, 2021). In chapter 1, frameworks that were created as part of this PhD thesis to inform and guide the incorporation of nutritional science in the development of new products are introduced. These frameworks are applied throughout the subsequent chapters in the design and development of an exemplar model of a functional food to support post exercise recovery and endurance exercise performance. This exemplar model took the form of a blackberry polyphenol enriched high protein milk. Chapter 2 reviews the literature on new product development and discusses the role of polyphenols and protein in post-exercise recovery and supporting endurance exercise performance. The review confirms the efficacy of dairy protein, particularly in the form of bovine milk, for muscle repair and regeneration post-exercise. RCTs have consistently shown the benefits of consuming between 1.2-1.6g/kg/day of high-quality protein for those undergoing frequent exercise. While there's growing evidence to support the use of plant-derived polyphenols for exercise-induced muscle damage (EIMD) recovery and endurance exercise performance, gaps remain in understanding their mechanisms, dosing, and optimal dietary sources. Chapter 3 presents an online survey that assesses the nutrition priorities, practices and preferences of athletes and active individuals. This survey was designed as part of this thesis following a series of focus group sessions with athletes of various levels and backgrounds. This survey provides key end-user insights into the nutritional wants and needs of athletes and active individuals. Key findings highlight muscle recovery as the primary nutritional priority among the athletic community and reveal a clear preference for food product forms over supplements. The data collected provides invaluable guidance for new product development in sports nutrition and allows the meaningful incorporation of end-user insights into the process. Chapter 4 bridges a crucial knowledge gap by conducting a systematic review and meta-analysis investigating the efficacy of flavonoid-rich polyphenols to support post-exercise recovery. The meta-analysis of 26 randomised controlled trials (RCTs) observed significant benefits in muscle strength and soreness recovery post intensive exercise. However, a notable limitation in the included studies was the inadequate characterisation of the polyphenol subclasses and dosages used, emphasising the need for more detailed reporting in future human studies. Chapter 5 presents an RCT assessing the efficacy of the RubusElite beverage prototype to support post-exercise recovery. Results suggest that this beverage augments recovery of muscle strength and reduces muscle soreness in comparison to both high protein and low protein milks. In collaboration with RubusElite project partners, this RCT includes detailed characterisation of the beverage's polyphenol content and a verification of polyphenol stability within the treatment beverage for the study duration. Chapter 6 further investigates the efficacy of the RubusElite prototype in relation to physical performance during a 15km cycling trial. In contrast to previous findings, no significant improvement in performance or exertion-related measures was observed. However, thorough polyphenol characterisation alongside these findings offers critical insights into the lack of observed benefits and provides direction for the reformulation of the prototype. This also provides considerable insights into future RCT design to reassess the efficacy of the reformulated prototype. In summary, this thesis offers a comprehensive investigation into the development of performance nutrition products through the creation of an exemplar model using novel frameworks which allow for the incorporation of scientific best practice. It provides innovative insights into the role of polyphenols and protein in supporting exercise and is one of the first undertakings to assess their efficacy in combination. By combining rigorous scientific evaluation, consumer insights, and product prototyping, the research offers a comprehensive roadmap for future product development in the rapidly evolving domain of performance nutrition.Item Novel ingredients and emerging processing technologies in the development of clean label, phosphate-reduced meat products(University College Cork, 2022-08) Palanisamy Thangavelu, Karthikeyan; Kerry, Joseph; Tiwari, Brijesh; Álvarez, Carlos; TeagascPhosphate additives are used in numerous processed foods as stabilisers and emulsifiers. They are present in up to 65% of processed meat products. However, consumer preferences for more natural and less processed foods have resulted in clean-label growth trends, meaning shorter ingredient declarations avoiding ingredients unfamiliar to the consumer. Due to the unique characteristics of phosphates, their removal, while maintaining product quality, is challenging. As an initial study (Chapter 2), a survey assessing the Irish consumer’s (n=548) intention to purchase phosphate-reduced processed meat products employing the Theory of Planned Behaviour (TPB) was conducted. Results showed that Irish consumers positively intended to purchase phosphate-reduced processed meat products if widely available. Based on survey findings, this thesis research explored the possibilities of developing high-quality, phosphate-replaced/reduced processed meat products employing natural ingredients and additionally employing novel processing technologies. This objective was achieved by carrying out two important processes: modification of potential phosphate-replacers and meat structure modification using novel processing technologies and accomplished by carrying out four experimental studies. The first experimental study (Chapter 3) examined the phosphate-replacing ability of two dietary fibre-rich food co-product ingredients, namely; apple pomace (AP) and coffee silverskin (CSS), in Irish breakfast sausage formulations. A specialised response surface methodology developed using Mixture design software created 18 sausage formulations containing different sodium tripolyphosphate (STPP), AP and CSS concentrations. Results showed that the addition of ingredients improved WHC (P<0.001) and decreased the cook loss (P<0.001), hardness (P<0.001), chewiness (P<0.001) and day 9 TBARS (P<0.018) values. Software analysis of results predicted three optimised phosphate-reduced sausage formulations based on the desirability response method. Following chapter 3, efforts were made to enhance the functional properties of AP and CSS using Power Ultrasound (US) technology Chapter 4). This investigated the effect of US treatment of 20 kHz, 250 W at different time intervals of 15 and 30 minutes on the techno-functional properties of AP and CSS, such as water and oil absorption capacity (WAC and OAC), particle size, viscosity, colour and total fibre content. Results indicated that US treatment on ingredients for 15 and 30 minutes improved WAC and OAC of both ingredients (Significant only for AP). Observation showed that functionality improved with increased treatment duration. This demonstrated that US treatment can create beneficially-functional properties in food co-products or ingredients, such as with AP and CSS powders. Combining Chapters 3 and 4, a comparative study (Chapter 5) was conducted employing US-treated (30 minutes) ingredients in the three optimised phosphate-reduced sausage formulations obtained from the mixture design software. Results showed that the addition of US-treated AP and CSS to all the formulations increased WHC (P<0.05), emulsion stability (TEF %) (P<0.05), and decreased cook loss (P<0.05), demonstrating that the addition of US-treated AP and CSS can improve phosphate-reduced sausage quality. Finally, in Chapter 6, a strategy of using High-Pressure Processing (HPP) technology to alter meat functionality was employed for further sausage quality improvement. Study results showed that HPP (150 MPa for 5 mins) produced positive changes in the water holding capacity (WHC) (P<0.05) and cook loss (P<0.05) of sausage formulations when compared to non-HPP treated equivalents. In conclusion, there is potential to manufacture sausages with reduced phosphate concentration using novel processing technologies and clean label ingredients, such as those used in this study. Overall, the research presented showed the wide application scope that exists for non-thermal novel processing technology. With further optimisation, these ingredients and the processing technologies employed could be used to produce a wide range of healthier and higher-quality processed meat products.Item Influence of dietary factors on the macro and micro-composition of bovine milk for use in protein ingredient powder manufacture(University College Cork, 2021-12) Magan, Jonathan B.; Kelly, Alan; O'Callaghan, Tom; McCarthy, Noel A.; Dairy Research Ireland; TeagascThe increasing frequency of “grass-fed” labelling claims in dairy product marketing, predicated in part on improved product quality and nutritional benefits associated therewith, has necessitated both rigorous experimental data to determine the relative differences in the composition of milk from grass-fed and non-grass-fed cows and robust methods for verifying these labelling claims. The “Grass-fed Standard” established by Bord Bia in 2020 is the first scientifically-backed standard in use internationally, which is founded on the somewhat unique pasture-based dairy production system practiced in Ireland. The compositional and functional benefits associated with products derived from pasture-fed cows have thus far been focused on business-to-consumer products. The effect of pasture-based production relative to the conventional indoor production system utilised most widely throughout the world on the composition and functional properties of “business-to-business” milk powder products, which represent a major aspect of Irish dairy production, remained to be established. Variation in the composition and functional properties of dairy products arises due to numerous factors, including feed composition, which can differ depending on the type of production system practiced. Therefore, the objective of this research was to investigate the effect of perennial ryegrass only (GRS), perennial ryegrass/white clover pasture (CLV) and indoor total mixed ration (TMR) feeding systems on the composition and functional properties of bovine milk-based protein ingredients. There was a significant effect of feeding system on the concentration of metabolite compounds and B vitamins in skim milk powder (SMP) and whey ingredients, which were distinguishable by liquid chromatography-mass spectrometry. Concentrations of vitamins B1, B2 and B7 were significantly higher in GRS and CLV samples than TMR samples, for which concentrations of vitamin B3 and B3-amide were higher than in CLV and GRS samples, respectively. Gross compositional parameters were similar between the feeding systems; however, the CLV and TMR systems were associated with high concentrations of non-protein nitrogen and high heat stability in whole milk powder and SMP samples. Some differences in total amino acid (AA) composition were also exhibited between WMP and SMP samples from each diet, which suggests that AA profile may be responsive to dietary variation. Yoghurts produced from GRS and CLV-derived WMP were typified by significantly higher gel strength and textural firmness than those derived from TMR, despite significantly higher concentrations of palmitic acid in TMR samples. Fatty acid (FA) profiles of WMP samples from each diet were similar to those in the literature produced from pasture or concentrate-based systems. The level of FA unsaturation and carotenoid content could also distinguish between pasture and TMR samples using Raman spectroscopy. The mineral composition of WMP, SMP and whey protein concentrate (WPC) samples from each diet did not vary significantly, with the exception of selenium and iodine, which were consistently, and significantly, higher in TMR samples than GRS and CLV samples. The viscosity of GRS-derived skim milk concentrate was significantly higher than that for TMR, but the effect of diet on the heat-dependent viscosity of dispersions of skim milk with WPC was not as substantial as the differences between WPC types, with micellar casein whey being most stable on heating, and acid WPC the least stable. Proteomic and peptidomic analysis of WMP and digested WMP samples determined qualitative and quantitative differences in proteins and peptides arising from each diet. In conclusion, this research demonstrated that the influence of bovine diet on milk components is not limited to gross compositional factors, but the micro-composition and functional properties, such as heat stability and acid-induced gelation, of value-added dairy products can also be influenced by feeding practices. This research will be of most interest to the manufacturers of dairy powder ingredients, such as SMP and WPC and premium WMP products in establishing the commercial point-of-difference for pasture or concentrate-derived products along with the unique compositional elements and functional behaviour associated with products from the three feeding systems investigated herein. Furthermore, this research will aid in ingredient selection for manufacturers of value-added dairy commodities, such as infant milk formula. Finally, this research contributes to the list of compositional variables which demonstrate potential for differentiation between feeding systems, providing preliminary information, relating to the establishment of robust analytical methods for verification of “Grass-fed” labelling claims for milk powder products to international entities responsible for policy implementation, such as Bord Bia.Item Assessment of blue whiting protein hydrolysate bioactivities using cell culture models(University College Cork, 2022-07-21) Heffernan, Shauna; O'Brien, Nora M.; Giblin, Linda; Department of Agriculture, Food and the Marine, IrelandLow-value underutilised blue whiting fish represents a potential profitable source of protein for the generation of high-value, health-enhancing fractions. The research described in this thesis assessed the bioactive potential of blue whiting soluble protein hydrolysates (BWSPHs) using cellular model systems. Minced, deboned blue whiting was initially hydrolysed at laboratory scale to develop a protocol for the reproducible generation of eleven different BWSPHs. Cellular bioactivity analysis of these eleven hydrolysates indicated that none of the BWSPHs tested exhibited satiating activity, antioxidant activity, immunomodulatory activity or anti-obesity activity as measured using specific cellular models. However, six BWSPHs did exhibit anti-diabetic activity in vitro, therefore, these six BWSPHs were prepared at semi-pilot scale and all of the above bioactivities were reassessed in greater detail. The antioxidant and immunomodulatory activities of the six industrial-scale BWSPHs before simulated gastrointestinal digestion (SGID) (BW-SPH-A to BW-SPH-F) and after SGID (BW-SPH-A-GI to BW-SPH-F-GI) were assessed in stimulated murine RAW264.7 macrophage. Hydrolysate BW-SPH-A (0.5%, w/v dw), both pre- and post-SGID, increased the endogenous antioxidant, reduced glutathione (GSH), in tert-butylhydroperoxide (tBOOH)-treated cells and reduced reactive oxygen species (ROS) in H2O2-challenged RAW264.7 cells compared with stimulated controls (p<0.05). In vitro digested hydrolysate BW-SPH-F-GI (0.5%, w/v dw) induced immunostimulating effects in lipopolysaccharide (LPS)-activated RAW264.7 macrophages though increasing pro-inflammatory cytokine interleukin (IL)-6 and tumour necrosis factor (TNF)-α levels compared with the LPS-stimulated control (p<0.05). The satiating potential of the six BWSPHs was then assessed in murine enteroendocrine STC-1 cells. The ability of BWSPHs and SGID BWSPHs to modulate the secretion and/or production of satiety hormones glucagon-like peptide-1 (GLP-1), cholecystokinin (CCK) and peptide YY (PYY) in STC-1 cells was studied as well as the signalling pathway activated by BWSPHs to modulate the secretion of these hormones. All BWSPHs (BW-SPH-A to BW-SPH-F) (1.0%, w/v dw) increased active GLP-1 secretion and proglucagon production in STC-1 cells compared to the basal control (Krebs-Ringer buffer) (p<0.05), possibly via intracellular calcium signalling, however this activity was lost following SGID. In addition, neither pre- nor post-SGID hydrolysates affected epithelial barrier integrity or stimulated IL-6 secretion in differentiated Caco-2/HT-29MTX co-cultured cells. The anti-obesity effects of BWSPHs and SGID BWSPHs was investigated using the murine 3T3-L1 cell line. Before SGID, hydrolysates BW-SPH-A, -B, -C and -F (1.0%, w/v dw) reduced triglyceride accumulation during preadipocyte differentiation (p<0.05), however none of the hydrolysates hydrolysed triglycerides in fully mature adipocytes. Interestingly, after SGID, all hydrolysates reduced triglyceride accumulation during differentiation and all except one BWSPH increased glycerol levels in mature adipocytes compared with the differentiated controls (p<0.05). Two anti-adipogenic hydrolysates, BW-SPH-A and BW-SPH-F, and their corresponding in vitro digests were observed to modulate triglyceride accumulation during preadipocyte differentiation via down-regulating the expression of key adipogenic transcription factors (peroxisome proliferator activated receptor (PPAR)-γ and CAAT (controlled amino acid therapy)/ enhancer binding protein (C/EBP)-α) compared with the differentiated controls (p<0.05). These SGID hydrolysates also exhibited anti-obesity activities following simulated intestinal permeation. After a 4 h exposure of specific SGID BWSPHs to 21-day differentiated Caco-2/HT-29MTX co-cultured cells, cell basolateral was subsequently observed to exhibit anti-adipogenic and adipolytic activities in 3T3-L1 cellular models. In addition, exposure of 3T3-L1 preadipocytes to hydrolysate BW-SPH-A during differentiation also increased GSH concentration upon stimulation with antioxidant tBOOH compared with the tBOOH control (p<0.05). Specific BWSPHs were also observed to reduced adiponectin production in LPS-stimulated cells compared with the LPS control (p<0.05). To conclude, certain BWSPHs exhibited significant bioactivities before SGID, after SGID, and after simulated intestinal absorption, therefore may have potential as health-enhancing functional food ingredients.Item Innovative processing strategies for the development of highly-dispersible, protein-enriched dairy powders(University College Cork, 2022-04-01) McSweeney, David J.; O'Mahony, Seamus Anthony; McCarthy, Noel A.; Department of Agriculture, Food and the Marine, Ireland; TeagascThe application of milk protein concentrate (MPC) powder ingredients, in the formulation of nutritional products (e.g., follow-on infant formula, protein bars, clinical and sports performance beverages) continues to drive research interest among scientists to better understand, predict and control the physical and functional properties of such powders. They represent a rich source of versatile milk proteins and are prepared from the ultrafiltration and diafiltration of skim milk, followed by evaporation and spray drying. However, the primary technological hurdle limiting their application is suboptimal rehydration performance in water, specifically slow and/or incomplete dispersion and solubility. This presents a significant challenge for the food and beverage industry, particularly in relation to creating more sustainable manufacturing conditions and optimising the quality of final products. The objective of this thesis was to investigate the impact of composition (e.g., protein content), processing parameters (e.g., heat treatment) and novel technologies (e.g., gas injection) on the physical and functional properties of MPC powders. Initial studies on MPC ingredients demonstrated that high-protein content (>65%, w/w) negatively influenced bulk powder (e.g., density and flowability) and rehydration properties, with results generally improving as protein content decreased to 40-55% (w/w). Heat treatment of liquid MPC prior to spray drying demonstrated that thermal processing (≥100 °C for 30 s) significantly increases concentrate viscosity and impairs powder rehydration performance, likely due to protein aggregation, but can provide a pH-dependent improvement in heat stability. Research involving the injection of nitrogen gas (N2) into liquid MPC prior to spray drying generated regular and agglomerated (i.e., fines returned to the top of the spray dryer) powders with distinct physical and bulk handling properties and significantly improved dispersion and dissolution. Regular MPC powders produced using N2 injection (NI) had lower density, poorer flowability, increased specific surface area, and altered surface composition. However, these powder particles underwent significant breakdown during reconstitution in both ambient and warm water, demonstrating that NI directly prior to spray drying can enhance the dispersion and solubilisation of micellar casein-dominant dairy powders. These powders were further processed downstream of drying using milling to alter powder properties and yielded samples with higher density, lower air content and altered surface composition, and while they did not disperse and solubilise to the same extent, their rehydration properties remained better than those produced without NI. This thesis provides new insights into the relationship between processing modifications and the physicochemical properties of milk protein concentrate, and will support the development of techno-functional, protein-enriched dairy ingredients for incorporation into nutritional food and beverage products.