Design of microcapsules with bilberry seed oil, cold-set whey protein hydrogels and anthocyanins: Effect of pH and formulation on structure formation kinetics and resulting microstructure during purification processing and storage.

Encapsulation of polar and non-polar bioactive compounds from bilberries was achieved by designing microcapsules with bilberry seed oil (BSO) distributed in an aqueous phase of anthocyanins (AC) stabilized by whey protein isolate (WPI). Non-thermal emulsification method (o/w/o) was developed and the effect of pH (3 or 4.5), concentration of WPI (8.4-10.8% w/w), addition of AC (72-216 ppm) and emulsifier on the structure-forming kinetics, resulting microstructure during storage and after centrifugation and washing was investigated. Agglomeration of BSO was observed in all microcapsules at pH 4.5 due to slow gelling process and in samples at pH 3 at low concentrations of WPI (≤8.4%). Capsules with pH 3 (9.6-10.8% WPI) had weak structures but as the gelling process was faster, it generated an even distribution of BSO droplets. All samples at pH 4.5 and samples with WPI concentration ≥10.8% at pH 3 exhibited intact structures after centrifugation and washing.

Effect of anthocyanins on lipid oxidation and microbial spoilage in value-added emulsions with bilberry seed oil, anthocyanins and cold set whey protein hydrogels.

The objective of this work was to explore the storage properties of a structured oil-in-water emulsion containing both water- and fat-soluble bioactive compounds from bilberries (Vaccinium myrtillus L.). Bilberry seed oil (BSO) was dispersed in a continuous aqueous phase of anthocyanins (AC) and whey protein isolate. The microstructure was evaluated using light microscopy and the effect of anthocyanins on lipid oxidation and microbial growth was investigated. The results showed that it was possible to generate a stable emulsion structure that resisted phase separation during 25 weeks of storage. Gas chromatography-mass spectrometry measurements of the fatty acids in the BSO during storage showed that AC had a protective effect against lipid oxidation. The AC did not have an antimicrobial effect against the investigated strains Zygosaccharomyces bailii (ATCC 42476) and Aspergillus niger (ATCC 6275 (M68)).