Journal Articles
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Item Emulsifying properties of hemp and whey protein complexes achieved by microparticulation(Elsevier Ltd, 2026-03-01) Ma S; Ye A; Singh H; Acevedo-Fani AHemp is a sustainable source of protein. However, the utilisation of commercial hemp protein (HP) is limited due to its poor functionality. This study provided a microparticulation method to produce hybrid microparticles by complexing HP and whey protein isolate (WPI), and investigated their emulsifying potential. The emulsions, composed of 10 % oil and 0.25–1.8 % protein (non-microparticulated or microparticulated HP/WPI), were produced and the impact of microparticulation on the emulsifying ability of HP/WPI was explored using static light scattering, CLSM, TEM and SDS electrophoresis analysis. The results showed that non-microparticulated HP/WPI stabilised emulsions exhibited preferential whey protein adsorption at the oil-water interface, leading to sufficient protein coverage at most protein concentrations (0.25–1.8 %) with relatively small droplet size (∼0.5 μm) and minimal flocculation. In contrast, in the 'emulsifier-poor' regime (0.25–1 %), microparticulated HP/WPI stabilised emulsions displayed larger droplet size with clear signs of bridging flocculation. However, when the protein concentration was sufficient (≥1.5 % protein), it reached a similar droplet size as that of non-microparticulated HP/WPI emulsion with minimal flocculation. Microparticulation increased HP loading at the interface, while emulsions stabilised by non-microparticulated HP/WPI showed less HP adsorption. Transmission electron microscopy further confirmed the microparticle coverage. Moreover, the heat stability of microparticulated HP/WPI stabilised emulsions increased, compared with non-microparticulated HP/WPI. These findings highlight the potential of microparticulated HP/WPI systems in the application of emulsification and enhance HP applications in the food industry.Item Secretion of inflammatory mediators by human intestinal epithelial cells incubated with gastric digesta of emulsion gels containing capsaicinoids: Implication on gastric irritation(Elsevier B V, 2025-06) Luo N; Wolber FM; Singh H; Ye AAn in vitro method was developed to test gastric irritation by quantifying the secretion of interleukin-8 (IL-8) by human intestinal epithelial cells Caco-2 after incubation with gastric digesta of emulsion gels containing capsaicinoids (CAP) obtained from simulated dynamic gastric digestion. The emulsion gel structure was modified using different emulsifiers: whey proteins versus Tween 80. Results indicate that both the CAP and Tween 80 molecules were proinflammatory to Caco-2 cells and stimulated cells to produce IL-8. Gastric digesta from CAP-loaded Tween 80 emulsion gel stimulated significantly more IL-8 production than CAP-loaded whey protein emulsion gel, possibly because of the presence of Tween 80 and also, because more CAP molecules were released from Tween 80 emulsion gel during gastric digestion. Tween 80 emulsion gel had a loose structure; it was easily broken down into smaller pieces and had large amounts of oil droplet liberation from the protein matrix, which would promote the release of CAP molecules, leading to higher IL-8 production. On the other hand, whey-protein-coated oil droplets had strong connections with surrounding protein matrix and were well protected during gastric digestion; the release of CAP molecules was much less. This study suggests that by modifying the structure of the foods, the gastric digestion behaviour can be modified, which would affect the release behaviour of CAP molecules and influence gastric irritation / inflammation.Item Heat-induced interactions between microfluidized hemp protein particles and caseins or whey proteins(Elsevier Ltd, 2025-01) Ma S; Ye A; Singh H; Acevedo-Fani AThe rising demand for sustainable proteins leads to increased interest in plant proteins like hemp protein (HP). However, commercial HP's poor functionality, including heat aggregation, limit its use. This study explored the heat-induced interactions of hemp protein particles (HPPs) with milk proteins, specifically whey proteins and caseins. Using various analysis techniques-static light scattering, TEM, SDS electrophoresis, surface hydrophobicity, and free sulfhydryl content-results showed that co-heating HPPs with whey protein isolate (WPI) or sodium caseinate (NaCN) at 95 °C for 20 min reduced HPPs aggregation. HPPs/WPI particles had a d4,3 of ∼3.8 μm, while HPPs/NaCN were ∼1.9 μm, compared to ∼27.5 μm for HPPs alone. SDS-PAGE indicated that whey proteins irreversibly bound to HPPs, through disulfide bonds, whereas casein bound reversibly, possibly involving the chaperone-like property of casein. This study proposes possible mechanisms by which HPPs interact with milk proteins and impact protein aggregation. This may provide opportunities for developing hybrid protein microparticlesItem The physicochemical properties of β-carotene emulsions stabilized by whey protein/octenyl succinic anhydride (OSA)-modified-starch complexes: Influence of OSA substitution degree of starch(Elsevier Ltd, 2024-04-01) Lin Q; Yang X; Liu Y; Lu Y; Liu W; Han J; Singh H; Ye AComplexes formed between heated whey protein isolate (HWPI) and octenyl succinic anhydride (OSA)-modified starches were prepared to stabilize β-carotene-containing oil-in-water emulsions. The zeta-potential, turbidity, particle size, and microstructure of the complexes were determined to evaluate the impact of the degree of substitution (DS) of OSA-modified starch on the complexes' structure. HWPI and OSA-modified starches with low DS values formed elongated complexes. With increasing DS, the particle size of the complexes reduced. In comparison to the emulsions stabilized by HWPI or OSA-modified starches, the emulsions stabilized by HWPI/OSAS complexes exhibited superior protection of β-carotene during storage under acidic conditions. When the DS of OSA-modified starch increased, the particle size of emulsions stabilized by the complexes decreased, with less droplet aggregation occurring. The physical stability of these emulsions against storage time, ions, and thermal process showed a positive relationship with the DS, while the β-carotene retention in the emulsions during storage showed a negative relationship with the DS. The greater physical stability of the complex-stabilized emulsions containing OSA-modified starch with a higher DS may be ascribed to enhanced electrostatic repulsion among oil droplets and the formation of a more rigid and denser surface structure in the presence of more OSA groups.Item Digestion behaviour of capsaicinoid-loaded emulsion gels and bioaccessibility of capsaicinoids: Effect of emulsifier type(Elsevier B V, 2023-03-06) Luo N; Ye A; Wolber FM; Singh H; Sun QIn this study, the effect of emulsifier type, i.e. whey protein versus Tween 80, on the digestion behaviour of emulsion gels containing capsaicinoids (CAPs) was examined. The results indicate that the CAP-loaded Tween 80 emulsion gel was emptied out significantly faster during gastric digestion than the CAP-loaded whey protein emulsion gel. The Tween-80-coated oil droplets appeared to be in a flocculated state in the emulsion gel, had no interactions with the protein matrix and were easily released from the protein matrix during gastric digestion. The whey-protein-coated oil droplets showed strong interactions with the protein matrix, and the presence of thick protein layer around the oil droplets protected their liberation during gastric digestion. During intestinal digestion, the CAP-loaded Tween 80 emulsion gel had a lower extent of lipolysis than the CAP-loaded whey protein emulsion gel, probably because the interfacial layer formed by Tween 80 was resistance to displacement by bile salts, and/or because Tween 80 formed interfacial complexes with bile salts/lipolytic enzymes. Because of the softer structure of the CAP-loaded Tween 80 emulsion gel, the gel particles were broken down much faster and the oil droplets were liberated from the protein matrix more readily than for the CAP-loaded whey protein emulsion gel during intestinal digestion; this promoted the release of CAP molecules from the gel. In addition, the Tween 80 molecules displaced from the interface would participate in the formation of mixed micelles and would help to solubilize the released CAP molecules, leading to improved bioaccessibility of CAP. Information obtained from this study could be useful in designing functional foods for the delivery of lipophilic bioactive compounds.Item Tuning heat-‐induced colloidal aggregation of whey proteins, sodium caseinate and gum arabic: effect of protein composition, preheating and gum arabic level(ELSEVIER SCI LTD, 2014) Loveday, SM; Ye, Aiqian; Anema, Skelte G; Singh, HarjinderHeating can drive the colloidal complexation of negatively-‐charged proteins and polysaccharides by strengthening hydrophobic interactions and denaturing proteins, thereby exposing reactive sites for covalent and noncovalent bonding. We have previously shown that stable colloidal aggregates comprising whey protein, sodium caseinate and gum arabic can be produced by careful selection of heat treatment, pH and protein type. Here we tested how the size, composition, charge and morphology of colloidal aggregates are affected by the amounts of whey protein, sodium caseinate and gum arabic, as well as the thermal history of the proteins. Increasing amounts of whey protein resulted in larger particles, which were more prone to precipitate. Preheating whey protein slightly enhanced aggregation, and this effect was mitigated when sodium caseinate was present during preheating (chaperone effect). Increasing amounts of gum arabic produced larger particles with less charge, but the gum arabic effect was statistically confounded with ionic strength. We believe that both covalent (disulphide) and noncovalent interactions among protein molecules are required to overcome electrostatic repulsion at pH 7 and form stable aggregates.Item Heat-induced colloidal interactions of whey proteins, sodium caseinate and gum arabic in binary and ternary mixtures(Elsevier Ltd, 2013-11) Loveday SM; Ye A; Anema SG; Singh HMany food-grade proteins and polysaccharides will aggregate together when acidified or heated, due to electrostatic and hydrophobic interactions. At low concentrations, aggregates are soluble and colloidally stable, and they have potential applications as Pickering emulsifiers and nutrient carriers. Sodium caseinate (SC) and gum arabic (GA) at pH. 7 will form colloidal aggregates when heated, but aggregation is largely reversed on cooling. Whey proteins (in the form of whey protein isolate, WPI) will aggregate irreversibly with GA when they are heated together, but aggregation is often so rapid and extensive that aggregates precipitate. Here we sought to overcome those limitations, and to develop an in situ method for quantifying heat-induced aggregation. Aggregation was measured using temperature-controlled dynamic light scattering equipment and transmission electron microscopy. Combinations of SC, WPI and GA were heated at either pH. 7 or 3.5, and the weight ratio of protein to polysaccharide was held at 1:5 for simplicity. Heat-induced colloidally stable aggregates of SC. +. WPI. +. GA did not dissociate on cooling. Aggregation was measured in situ, both in temperature ramps and with isothermal experiments. In situ measurement allowed us to avoid potential artefacts stemming from the temperature changes and measurement delays associated with ex situ measurements. This work demonstrated how the size and heat-stability of colloidal protein-polysaccharide aggregates can be tailored by judicious selection of proteins, pH and heat treatment.Item Acute effects of whey protein, alone and mixed with other macronutrients, on blood pressure and heart rate in older men(BioMed Central Ltd, 2022-12) Oberoi A; Giezenaar C; Lange K; Jones KL; Horowitz M; Chapman I; Soenen SBACKGROUND: Caloric supplements are increasingly used by older people, aiming to increase their daily protein intake. These high caloric drinks, rich in glucose and whey-protein in particular, may result in potential harmful decreases in blood pressure (BP). The effect of ingesting whey-protein with glucose and fat on BP is unknown. It has also been assumed that the maximum fall in systolic blood pressure occurs within 2 h of a meal. METHODS: This study aimed to determine in older men, the effects of whey-protein, alone and mixed with other macronutrients, on systolic (SBP) and diastolic (DBP) blood pressure and heart rate (HR) in older men for 3 h. Thirteen older men (age 75 ± 2yrs; body mass index (BMI) 25.6 ± 0.6 kg/m2) ingested a drink on separate study days: (i) 70 g whey-protein (P280); (ii) 14 g whey-protein, 28 g carbohydrate, 12.4 g fat (M280); (iii) 70 g whey-protein, 28 g carbohydrate, 12.4 g fat (M504); or (iv) a non-caloric control drink (C). RESULTS: SBP decreased after all three nutrient drinks compared to the C, with the greatest reduction after the M504 drink (P = 0.008). Maximal decreases in SBP (C: -14 ± 2 mmHg, P280: -22 ± 2 mmHg, M280: -22 ± 4 mmHg, M504: -24 ± 3 mmHg) occurred about 2 h after drink ingestion and this fall was sustained thereafter (120-180 min: P280 and M504 vs. C P < 0.05). Maximum DBP decreases and HR increases occurred after M504, with no differences between the effects of the P280 and M280 drinks. CONCLUSIONS: The effects of whey-protein containing drinks to lower BP and increase HR appear to be primarily dependent on their energy content rather than macronutrient composition and may persist for at least 3 h after ingestion,. Pure whey-protein drinks may represent the best approach to maximize protein intake without increasing the potential for deleterious BP falls in older people. TRIAL REGISTRATION: ACTRN12614000846628 , 14/03/2019.