ORCID Profile
0000-0002-9016-1291
Current Organisation
University of Massachusetts Amherst
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Publisher: Informa UK Limited
Date: 27-09-2021
Publisher: Elsevier BV
Date: 09-2019
DOI: 10.1016/J.FOODRES.2019.05.043
Abstract: Oil-in-water emulsions are the main component of creamers, which are used to cream cold or hot coffee. These emulsions must provide the required lightening power and remain physically stable when introduced into hot acidic coffee solutions. In this study, model oil-in-water emulsions stabilized with mixed emulsifiers of sodium caseinate (0.5%) and soy lecithin (0.5%) were fabricated and their physical properties were examined over a range of pH values (pH 3.5 to 7). These model oil-in-water emulsions had strong lightening power (L* ≈ 87) and good physical stability from pH 5.5 to 7 but were unstable to gravitational separation below pH 5 due to caseinate aggregation around its isoelectric point. Addition of λ-carrageenan (0.05 to 0.175%) to the formulations prior to homogenization effectively improved their pH stability, while addition of κ-carrageenan was ineffective. The significantly higher level of sulfated ester groups in λ-carrageenan may have created a strong electrostatic repulsion between the oil particles, inhibiting their association. Our study suggests that some of the caseinate in coffee creamers can be replaced with plant-based lecithins, but that a plant-based polysaccharide is also needed to ensure their stability when added to hot acidic coffees.
Publisher: Elsevier BV
Date: 08-2019
DOI: 10.1016/J.FOODRES.2019.04.032
Abstract: Demands for plant-based food and beverage products have escalated in recent years. However, many commercial coffee creamers are still being made using dairy derivatives such as sodium caseinate. Therefore, there is a need to investigate the replacement of dairy based proteins with plant-based alternatives. This study was carried out to systematically investigate the properties of model O/W emulsions stabilized by either sodium caseinate (0.25 to 1.5%) or soy lecithin (0.5 to 1.5%). The model emulsions were made of 10% medium chain triglyceride (MCT) oil-in-water emulsions at pH 7. All model O/W emulsions exhibited whitish appearances similar to that of commercial creamers and were effective at lightening black coffee, except those containing the lowest emulsifier concentrations i.e., 0.25% caseinate or 0.5% lecithin. The lightness of the model emulsions depended on the type and level of emulsifier used, with soy lecithin-stabilized emulsions having similar lightening power compare to that stabilized by sodium caseinate. No feathering or free oil were observed in the whitened coffees at the highest emulsifier level used. Mixtures of caseinate and lecithin emulsifiers were also used and model O/W emulsions with similar physical properties to that stabilized by sodium caseinate alone were produced. The mixed emulsifier-stabilized model emulsions had similar lightness when added to coffee than those stabilized by the in idual emulsifiers, suggesting similar stabilization mechanisms using these emulsifiers alone or in combination.
Publisher: Elsevier BV
Date: 2016
DOI: 10.1016/J.CARBPOL.2015.10.016
Abstract: Knowledge of the structure of polysaccharides is essential for understanding and controlling their functional properties. In this study, fucoidan was extracted from Holothuria tubulosa, a species of sea cucumber that has recently become commercially important. The primary structure of the H. tubulosa fucoidan was clarified using a combination of enzymatic degradation, methylation analysis, and NMR, and its chain conformation was further elucidated by utilizing high performance size exclusion chromatography combined with multiple angle laser light scattering and viscometry. The fucoidan was composed of a tetrafucose repeating unit [ → 3-α-L-Fucp2(OSO3(-))-1 → 3-α-L-Fucp2,4(OSO3(-))-1 → 3-α-L-Fucp-1 → 3-α-L-Fucp2(OSO3(-))-1 → ]. Its sulfate content was determined to be 31.2 ± 1.6% and the weight-average molecular mass was 1567.6 ± 34.1 kDa. The molecule adapted a random coil conformation in 0.15M NaCl solution (pH 7.4) at 25 °C, with a root-mean-square radius of 63.9 ± 1.8 nm and a hydrodynamic radius of 44.5 ± 4.5 nm. This is the first report on the chain conformation of sea cucumber fucoidan.
Publisher: Elsevier BV
Date: 11-2018
DOI: 10.1016/J.FOODRES.2018.07.012
Abstract: There is an increasing market for food and beverage products enriched in proteins and dietary fibers due to their potential health benefits. In this study, the effect of heating (85 °C, 20 min), microfluidization (20,000 psi), and pH (2 to 6.5) on the physicochemical properties of aqueous solutions containing mixtures of whey protein fibrils (7.5% WPF) and chitosan (0.5% CN) were examined. Heating of the mixed systems increased their turbidity and apparent viscosity, which was attributed to the formation of protein-rich particles. Interestingly, heating the mixed systems and then applying microfluidization led to phase separation and a lower apparent viscosity, which was attributed to high-pressure disruption of the whey protein fibrils. The pH of the systems significantly influenced their appearance, turbidity, particle size, and apparent viscosity, with high turbidity and viscosity, and large particle size occurring from pH 3.5 to 5.5. These effects were attributed to protein aggregation close to its isoelectric point (pH 5) coupled with electrostatic attraction between anionic groups on the whey protein and cationic groups on the chitosan. The addition of chitosan increased the net isoelectric point from pH 5 for pure whey protein to pH 6 for the mixed system. Overall, this study showed that the appearance and rheological properties of protein-dietary fiber mixtures could be manipulated by heating, microfluidization, and pH adjustment. This information may be useful for designing protein and fiber enriched food and beverage products with desirable physical and sensory properties.
Publisher: Elsevier BV
Date: 10-2020
Publisher: MDPI AG
Date: 28-09-2023
DOI: 10.3390/SU151914336
Location: United States of America
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for David Julian McClements.