Microencapsulation of oils using whey protein/gum arabic coacervates

Abstract

Microencapsulating sunflower oil, lemon and orange oil flavour was investigated using complex coacervation of whey protein/gum arabic (WP/GA). At pH 3.0-4.5, WP and GA formed electrostatic complexes that could be successfully used for microencapsulation purposes. The formation of a smooth biopolymer shell around the oil droplets was achieved at a specific pH (close to 4.0) and the payload of oil (i.e. amount of oil in the capsule) was higher than 80%. Small droplets were easier to encapsulate within a coacervate matrix than large ones, which were present in a typical shell/core structure. The stability of the emulsion made of oil droplets covered with coacervates was strongly pH-dependent. At pH 4.0, the creaming rate of the emulsion was much higher than at other pH values. This phenomenon was investigated by carrying out zeta potential measurements on the mixtures. It seemed that, at this specific pH, the zeta potential was close to zero, highlighting the presence of neutral coacervate at the oil/water interface. The influence of pH on the capsule formation was in accordance with previous results on coacervation of whey proteins and gum arabic, i.e. WP/GA coacervates were formed in the same pH window with and without oil and the pH where the encapsulation seemed to be optimum corresponded to the pH at which the coacervate was the most viscous. Finally, to illustrate the applicability of these new coacervates, the release of flavoured capsules incorporated within Gouda cheese showed that large capsules gave stronger release and the covalently cross-linked capsules showed the lowest release, probably because of a tough dense biopolymer wall which was difficult to break by chewing.

Mesophase separation and probe dynamics in protein–polyelectrolyte coacervates

“…Several applications of protein-PE coacervates have been utilized or proposed. First, protein-PE coacervation has long been used to microencapsulate oil droplets, 10,11 protein drugs 12,13 and enzymes. 14 Second, polyelectrolyte coacervation can be used to separate proteins, even those with similar pI.…”

Emulsion Delivery Systems for Functional Foods

“…Complexes of polysaccharides (arabic gum, xanthan gum, pectin, carrageenan and alginate) with food proteins (albumin, gelatin, casein and ␤-lactoglobulin) are generally recommended to form the microcapsules . For instance, a mixture of whey proteins and gum arabic can be used as coating material to encapsulate essential oils (Weinbreck et al 2004). An emulsion of the essential oil-in-water in the presence of whey protein is first prepared.…”

“…Omega-3 fatty acids (Wu et al 2005) and flavor oils (Weinbreck et al 2004) have been incorporated in filled hydrogel particles based on aggregative phase-separation procedure, whereas complex coacervation using gelatin and gum acacia has been used to protect omega-3 fatty acids (Lamprecht et al 2001). …”

A Review on Encapsulation of Oils

“…Suitable pH range depends on the types and the charges of biopolymers. While Weinbreck et al [138] determined that a smooth whey protein -gum arabic coacervate layer formed at pH 4, pH 5 was selected as the best operation point for chitosan -gelatine (B) coacervates [139]. Secondly, stirring rate and homogenization speed play an important role.…”

“…To the best of our knowledge, up to today, lemon and orange oil [138]; fish oil [147][148][149]; peppermint oil [150,151]; thyme oil [152]; sunflower oil [153]; cinnamon oil [154]; coriander oil [155]; lavender oil [156]; coffee oil [157]; flaxseed oil [158], olive oil [159]; palm oil [160]; citronella oil [139] and kiwi fruit seed oil [161] were successfully microencapsulated by coacervation technique. However, it should be noted that the composition of every oil substantially varies and this difference majorly affects the efficiency of coacervation method [162,163].…”