Influence of whey protein types on the bioaccessibility of β-carotene in different formulations: Emulsions vs microcapsules

Abstract

The processing on whey protein has been concerned due to its high nutritional values and allergenicity. However, how different whey proteins will affect the absorption efficiency of other nutraceuticals in the formula is still unclear. Hence, four commercial whey proteins, namely whey protein concentrate (WPC), whey protein rich in globular-membrane phospholipids (MPL), moderately hydrolyzed whey protein (MHP) and highly hydrolyzed whey protein (HHP), were selected as the stabilizer to prepare emulsions, which were then spray-dried into microcapsules. β-carotene was selected as the representative lipophilic ingredient to study the effect of whey proteins on its bioaccessibility using an in vitro digestion model. The results indicated that the average particle size of WPC, MPL, and MHP emulsions is approximately 140 nm, while that of HHP emulsion had particle size of 16 μm. The micro-scaled microcapsules stabilized by MHP were superior to others stabilized by WPC, MPL, HHP in dispersibility and encapsulation characteristics. During digestion, MPL and MHP reduced the aggregation behavior of emulsion particles in the stomach. Microcapsules demonstrated superior bioaccessibility of β-carotene by 1.49–1.66 times compared to emulsions, while MPL emulsions (51.89 ± 2.94%) and microcapsules (77.50 ± 0.78%) exhibited the highest β-carotene bioaccessibility, increased by 1.03–1.69 and 1.12–1.22 times, respectively, as compared to other proteins. These findings offer valuable insights into the additional benefit of different whey proteins in enhancing the absorption of lipophilic nutrients in formula milk.