Reducing carotenoid loss during storage by co-encapsulation of pequi and buriti oils in oil-in-water emulsions followed by freeze-drying: use of heated and unheated whey protein isolates as emulsifiers

Publication date: Available online 18 December 2019Source: Food Research InternationalAuthor(s): Talita Aline Comunian, Marluci P. Silva, Izabel Cristina Freitas Moraes, Carmen S. Favaro-TrindadeAbstractBuriti and pequi oils are rich in carotenoids and beneficial to human health; however, carotenoid oxidation during storage causes color loss in foods, making it difficult to use these oils in food products. This research aimed to encapsulate pequi oil and co-encapsulate pequi and buriti oils by emulsification using whey protein isolate (WPI) as an emulsifier in two forms, natural (unheated) and heated, followed by freeze-drying. The emulsions were studied by droplet size under different stress conditions, instability index, and rheology. The freeze-dried (FD) samples were studied after accelerated oxidation and the total carotenoid retention was determined; for the reconstituted FD, the zeta potential and droplet size were recorded after storage at 37 °C for 30 days. The emulsions were stable in all conditions, with average droplet sizes between 0.88 ± 0.03 and 2.33± 0.02 μm, and formulations with heated WPI presented the lowest instability index values. The FD’s zeta potential values ranged from -50 ± 3 to -32 ± 3 mV. The co-encapsulated oils presented higher carotenoid retention (50 ± 1 and 48 ± 1%) than the free oils (31 ± 2%) after 30 days. The oxidative stability indexes were 51 ± 4 and 46 ± 3 for the co-encapsulated oils with unheated and heated WPI, respect...
Source: Food Research International - Category: Food Science Source Type: research