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Effects of emulsifier type on physical and oxidative stabilities of algae oil‐in‐water emulsions

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International Journal of Food Science & Technology
Authors:
Hyeon‐Jun Chang
Hyeon‐Jun Chang
Hyeon‐Jun Chang
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Kwang‐Seup Shin
Kwang‐Seup Shin
Kwang‐Seup Shin
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Jeung-Hee Lee at Daegu University
Jeung-Hee Lee
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Abstract and Figures

Algae oil‐in‐water emulsions were prepared using sodium caseinate (SC, 0.5%), whey protein concentrate (WPC, 0.5%), and a mixture of TWEEN80 (T80, 0.5%), and SPAN80 (SP80, 0.6%), and their emulsification and oxidative stabilities during storage were compared. Oil droplet sizes of SC‐ and T80+SP80‐emulsions were smaller than that of WPC‐emulsion. Serum layer appeared in all emulsions from day 15, and serum layer thicknesses were higher in WPC‐emulsion than SC‐ and T80+SP80‐emulsions, but an excess layer oil was observed only at the top of T80+SP80‐emulsion until day 36. According to conjugated dienes, aldehydes, hydroperoxide and TBARS values, the oxidative stability of SC‐emulsion was better than those of WPC‐ and T80+SP80‐emulsions. This trend was also observed in fatty acid profiles of the emulsions showing the largest DHA reduction and palmitic acid increase in T80+SP80‐emulsion, followed by WPC‐ and SC‐emulsions. In present study, sodium caseinate formed stable algae oil‐in‐water emulsions with excellent antioxidative activity.
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Original article
Effects of emulsifier type on physical and oxidative stabilities of
algae oil-in-water emulsions
Hyeon-Jun Chang, Kwang-Seup Shin & Jeung-Hee Lee*
Department of Food and Nutrition, Daegu University, 201 Daegudae-ro, Gyeonsan-si, Gyeongsangbukdo 38453, Korea
(Received 31 May 2018; Accepted in revised form 12 September 2018)
Summary Algae oil-in-water emulsions were prepared using sodium caseinate (SC, 0.5%), whey protein concentrate
(WPC, 0.5%), and a mixture of TWEEN80 (T80, 0.5%), and SPAN80 (SP80, 0.6%), and their emulsifica-
tion and oxidative stabilities during storage were compared. Oil droplet sizes of SC- and T80+SP80-emul-
sions were smaller than that of WPC-emulsion. Serum layer appeared in all emulsions from day 15, and
serum layer thicknesses were higher in WPC-emulsion than SC- and T80+SP80-emulsions, but an excess
layer oil was observed only at the top of T80+SP80-emulsion until day 36. According to conjugated
dienes, aldehydes, hydroperoxide and TBARS values, the oxidative stability of SC-emulsion was better
than those of WPC- and T80+SP80-emulsions. This trend was also observed in fatty acid profiles of the
emulsions showing the largest DHA reduction and palmitic acid increase in T80+SP80-emulsion, followed
by WPC- and SC-emulsions. In present study, sodium caseinate formed stable algae oil-in-water emul-
sions with excellent antioxidative activity.
Keywords Algae oil, oil-in-water emulsion, oxidative stability, physical stability, sodium caseinate.
Introduction
Algae oil is vegetarian source oil produced from
microalgae and is rich in docosahexaenoic acid (DHA,
C22:6n3), eicosapentaenoic acid (EPA, C20:5n3), and
docosapentaenoic acid (DPA, C22:5n6). Recently, cus-
tomised algae oil products with a DHA:EPA ratio of
2:1 (Schizochytrium sp.), or DHA contents of 40%
~45% without any EPA (Crypthecodinium cohnii) have
been produced and commercialised from diverse
microalgae strains by adjusting the contents of DHA
and EPA (Nauroth et al., 2010; Winwood, 2013).
DHA is distributed in the brain, nervous tissues,
reproductive organs, and optic nerve cell membranes
in the human body (Horrocks & Yeo, 1999). DHA
reduces serum cholesterol and neutral lipid concentra-
tions as well as relieves oxidative stress, thereby pro-
tecting the human body from cardiovascular risk
factors (Horrocks & Yeo, 1999; Doughman et al.,
2007). DHA also plays a significant role in brain
development (Tanaka et al., 2012) and has anti-inflam-
matory activity, which is enhanced by DPA (Nauroth
et al., 2010). However, since DHA and DPA are
highly polyunsaturated fatty acids, algae oil is highly
susceptible to lipid oxidation and generates secondary
oxidation products that cause serious problems with
respect to food quality such as rancidity or off-flavor
volatiles.
In oil-in-water emulsions, oil droplets are dispersed
in aqueous phase. Emulsifiers are absorbed at interfa-
cial regions between the oil phase and aqueous phase,
and they affect lipid oxidation of the emulsions since
oxidation is assumed to start at the interface. There-
fore, the oxidative and physical stabilities of emulsions
are highly dependent on the type of emulsifier. There
are a few studies in which oil-in-water emulsions were
prepared with algae oils or fish oils containing large
amounts of n-3 unsaturated fatty acids, and their
physical and oxidation stabilities according to the
types of emulsifiers were evaluated (Faraji et al., 2004;
Mora-Gutierrez et al., 2010).
In a previous study that used caseins from bovine or
caprine serum (0.1~0.5%) as emulsifiers, formation of
hydroperoxide, and TBARS values were shown to be
reduced in 5% algae oil-in water emulsion (Mora-
Gutierrez et al., 2010), suggesting that the oxidative
stability of casein can be attributed to metal chelation
and scavenging of free radicals. Faraji et al. (2004)
reported that proteins (such as whey protein isolate) in
*Correspondent: Fax: +82-53-850-6839;
e-mail: jeunghlee@daegu.ac.kr
International Journal of Food Science and Technology 2019, 54, 1530–1540
doi:10.1111/ijfs.13981
©2018 Institute of Food Science and Technology
1530
... It is known to lower the risk of coronary artery disease [2], inhibit the onset of cardiac arrhythmia and cardiovascular disease [3,4], and prevent the accumulation of beta-amyloid that damages brain cells in patients with dementia [5]. Fish oil contains EPA (13.3%) and DHA (8.9%), while microalgal oil extracted from Schizochytrium sp. has high DHA (54.9%) and DPA (n-6; 11.9%) contents but low EPA content (0.8%) [6]. ...
... Fatty acids compositions of soybean oil, fish oil, and microalgal oil. (1) Values are expressed as the mean ± standard deviation (n = 3); (2) Not detected; (3) total saturated fatty acids; (4) total unsaturated fatty acids; (5) total monounsaturated fatty acids; (6) total polyunsaturated fatty acids. ...
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