Date of Award

2023

Document Type

Master Thesis

Degree Name

Masters of Science (Research)

Department

PHYSICAL SCIENCES

First Advisor

Dr. Jonathan O’Regan

Second Advisor

Dr. Liam Lewis

Abstract

The aim of this thesis was to investigate the nutritional, techno-functional and physicochemical properties of milk fat globule membrane (MFGM) enriched whey protein concentrate (WPC) ingredients. This research focused on the physicochemical, nutritional, techno-functional, and microstructural properties of MFGM-enriched whey protein concentrate (WPC) powder ingredients, which included 3 MFGM-enriched WPC ingredients and a WPC ingredient co-enriched with α-lactalbumin and MFGM. These were compared to parallel stream (WPC 80 and whey protein isolate (WPI)) and upstream, whole milk powder (WMP) bovine derived ingredients of varying macromolecular composition, including MFGM-enrichment. The macromolecular compositions of the MFGM-enriched WPC ingredients included fat contents ranging from 10.8–17.6% (4.59–6.76% total phospholipids) and 69.8–80.6% total protein. The powder characteristics of these powders were assessed for bulk handling, rehydration, and microstructural properties and differed between ingredients primarily due to the effects of fat and MFGM content, however, for samples where evidence of agglomeration was observed these properties were markedly improved. Results for flowability reflect this, as the MFGM WPC 3 ingredient showed a flow index of 7.56 ± 0.84 compared to 2.71 ± 0.20 for the α-lac MFGM WPC ingredient, despite the higher fat content, which has typically been shown to impair flowability of WPC ingredients (Barone et al., 2019). Additional differences in bulk handling properties extended to variances in bulk densities and compressibility, where a positive correlation was noted between increased cohesivity of powders and increased levels of compressibility. Rehydration properties of these powders were primarily influenced by the macromolecular composition, with factors such as higher protein and higher fat resulting in impaired wettability and dispersibility characteristics. Microstructural (morphology, surface roughness, appearance of air pockets) analysis provided improved understanding of how differences at the powder particle level resulted in differences to the bulk powder. These differences in nutritional and techno-functional powder properties are of importance during ingredient selection, as they may impact the means of addition used or process in which it is formulated into infant formula (IF) or other food products such as potential maternal drinks and nutritional bars. 8 The MFGM lipidomic characterisation of select whey protein ingredients which were either enriched in MFGM (MFGM WPC 1), α-lactalbumin (α-lac WPC), or MFGM and α-lac (α-lac MFGM WPC) were described. Model infant formulae (IF 1–3) containing these ingredients were also characterised, including microscopical analysis to assess distribution of MFGM components in the formula when rehydrated. Markers of MFGM enrichment, which included total phospholipids, including sphingomyelin, gangliosides, cerebrosides and cholesterol, varied between the raw ingredients. The quantification of α-lactalbumin and β-lactoglobulin were also included to assess the similarities or differences in the whey protein profiles of the raw materials and model IF. . In addition to this, microscopy and the use of selective lectin staining was employed to reveal the distribution of MFGM components in these formulae. Insights from this study revealed that the selective use of raw materials during the design of infant formulae can result in formulas which are enriched for bioactive components related to the MFGM while also enriching for specific proteins, thus further reducing the gap between infant formulas and human milk. An appendix is also included in this thesis whereby the use of correlation analysis was employed to aid in proteomic analysis of dairy proteins, including MFGM proteins, revealed that certain protein groups were highly correlated and thus can be removed from multiple reaction monitoring analyses without losing important information in addition to reducing the worklist and costs associated for proteomic evaluations of dairy protein ingredients. The findings of this thesis revealed insights into the many factors, namely the compositional, nutritional and techno-functional properties, that should be considered when determining the optimal selection of an MFGM-enriched ingredient, either as a potential stand-alone supplement or for inclusion into formulations or food products.

Access Level

info:eu-repo/semantics/openAccess

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