Lutein encapsulated in whey protein and citric acid potato starch ester: Construction and characterization of microcapsules
International Journal of Biological Macromolecules 220 (2022) 1–12
Available online 12 August 2022
0141-8130/© 2022 Elsevier B.V. All rights reserved.
Lutein encapsulated in whey protein and citric acid potato starch ester:
Construction and characterization of microcapsules
Wenqing Zhao
a
, Bo Zhang
a
, Wei Liang
a
, Xinyue Liu
a
, Jiayu Zheng
a
, Xiangzhen Ge
a
,
Huishan Shen
a
, Yifan Lu
a
, Xiuyun Zhang
a
, Zhuangzhuang Sun
a
, Gulnazym Ospankulova
b
,
Wenhao Li
a
,
*
a
Engineering Research Center of Grain and Oil Functionalized Processing in Universities of Shaanxi Province, College of Food Science and Engineering, Northwest A&F
University, 22 Xinong Road, Yangling 712100, Shaanxi, PR China
b
Kazakh Agrotechnical University, Zhenis avenue, 62, Nur-Sultan 010011, Kazakhstan
ARTICLE INFO
Keywords:
Microcapsule
Lutein
Physicochemical property
ABSTRACT
The poor water solubility and stability of lutein limit its application in industry. Microencapsulation technology
is an excellent strategy to solve these problems. This study used citric acid esteried potato starch and whey
protein as an emulsier to prepare oil-in-water lutein emulsion, and microcapsules were constructed by spray
drying technology. The effects of different component proportions on microcapsules' microstructure, physical
and chemical properties, and storage stability were analyzed. Citrate esteried potato starch had good emulsi-
fying properties, and when compounded with whey protein, the encapsulation efciency (EE) of microcapsules
increased, and the embedding effect of lutein improved. After microencapsulation, the solubility of lutein
increased signicantly, reaching over 49.71 %, and gradually raised with more whey protein content. Further-
more, the high proportion of whey protein helped improve microcapsules' EE and thermal properties, with the
maximum EE reaching 89.36 %. The glass transition temperatures of microcapsules were all higher than room
temperature, which indicated that they keep a stable state under general storage conditions. The experimental
results of this study may provide a reference for applying lutein in food and other elds.
1. Introduction
Lutein, a carotenoid existing in the macular area of the retina, has the
reputation of “international gold” and is widely found in fruits, vege-
tables, owers, and other plants. Lutein has remarkable antioxidant
activity in vitro, reducing the incidence of age-related diseases [1].
Furthermore, in vitro experiments have conrmed the anti-
inammatory effect of lutein in peripheral blood mononuclear cells of
patients with coronary heart disease, suggesting that lutein has a po-
tential role in solving chronic inammation in patients with coronary
heart disease [2]. Meanwhile, Ma [3] found that supplementation of
lutein and zeaxanthin can improve the early dysfunction of the central
retina in patients with early AMD. Therefore, the encapsulation and
preparation of lutein delivery systems for improving human eye health
have positive prospects and implications. However, lutein is highly
unsaturated and will lose its original active function after being
oxidized. Furthermore, lutein has poor water solubility, so it is difcult
to apply to food based on water. Due to the low water solubility of lutein,
fat-rich formulations (emulsion systems) can reduce degradation in the
food matrix by limiting the presence of hydrophilic free radicals [4]. Luo
[5] prepared the lutein-glucosyl sativoside (stevia-G)-hydroxypropyl
methylcellulose (HPMC) complex by antisolvent precipitation in com-
bination with a dynamic high-pressure microuidic method. The results
showed that when the optimal mass ratio of lutein, stevia-G, and HPMC
was 1:40:0.5, the apparent solubility of lutein reached 2805.47 ±24.94
μ
g/mL, which was about 5600 times of that of lutein crystal. However,
the problems of low bioavailability and poor stability remain to be
solved.
These problems have been gradually solved with the development
and maturity of microcapsule technology. The design and development
of a food microcapsule system have practical signicance and put for-
ward new requirements and challenges for edible embedding carriers. In
developing and utilizing new starch-based wall materials, the starch
ester is one of the microcapsule wall materials with broad prospects and
* Corresponding author.
E-mail address: liwenhao@nwsuaf.edu.cn (W. Li).
Contents lists available at ScienceDirect
International Journal of Biological Macromolecules
journal homepage: www.elsevier.com/locate/ijbiomac
https://doi.org/10.1016/j.ijbiomac.2022.08.068
Received 21 April 2022; Received in revised form 26 July 2022; Accepted 10 August 2022
International Journal of Biological Macromolecules 220 (2022) 1–12
2
development potential, with good emulsifying performance. It is also an
emulsier widely used in functional factor encapsulation systems.
Furthermore, potato starch is considered as an ideal raw material for
industrial production due to its wide availability, low price and envi-
ronmental friendliness. For example, Romero-Hernandez [6] used OSA
esteried taro starch as wall material and encapsulated avocado oil as a
lipophilic bioactive compound by spray drying to form microcapsules.
Citrate esteried starch is also one of the most crucial starch esters,
optimizing food processing performance and improving the texture and
sense of products. Lee [7] studied the effect of citrate esteried maca
starch as an O/W Pickering emulsion stabilizer. They found that it had a
small particle size and zeta potential and had high storage stability,
which indicated that citrate esteried starch could be used as a potential
substitute emulsier in the food industry. Zhang [8] used OSA starch as
an emulsier and wall material, and prepared β-carotene microcapsules
with a high load through wet grinding and spray drying coupling. Rocha
[9] used modied starch with lipophilic ingredients as an encapsulation
agent to microencapsulate lycopene by spray drying, which enhanced
the stability of lycopene and could release pigment in food. However,
the single modied starch wall material still lacks stability and solubi-
lity. Therefore, it is often used with protein or other colloids to increase
the encapsulation effect of microcapsules [10].
Whey protein has high nutritional value, easy digestion and ab-
sorption. It contains many active ingredients and has been applied in the
packaging carrier of various functional foods as an emulsier. It can
form a compact membrane structure in microencapsulation, effectively
package the core nutrients, protect the active ingredients from envi-
ronmental damage and slowly release them at specic locations [11].
Whey protein is an ideal wall material for encapsulating and delivering
nutrients due to its advantages of high nutritional value, excellent
functional properties, and anti-pepsin digestion [12]. Yi [13] studied the
interaction between whey protein isolation (WPI) and sodium caseinate
(SC) and hydrophobic lutein and their inuence on the chemical sta-
bility of lutein. The results showed that milk protein had a protective
effect on lutein against oxidation and decomposition, and the chemical
stability of lutein increased with the increase of protein concentration.
Liu [14] prepared whey protein nanoparticles and successfully encap-
sulated soy isoavones by the emulsication-evaporation method. The
encapsulation efciency reached 91.29 %–92.59 %, signicantly
improving the photochemical stability, antioxidant activity and
bioavailability of soy isoavones. Milk protein could be an effective
carrier of lipophilic health products.
At the same time, whey protein can also be used with carbohydrates
such as starch to encapsulate bioactive substances. For example, Sunil
[15] used a mixture of whey protein and carbohydrates (maltodextrin
and gum) to prepare a stable curcumin emulsion, spray-dried to obtain
curcumin microcapsules were resistant to simulated digestive digestion.
Furthermore, Cao [16] studied the effects of different concentrations of
acetylated tapioca starch and pH value on the droplet aggregation of a
multi-component emulsion mixture containing whey protein. After heat
treatment, whey protein can expose more hidden peptide and amino
acid side chains, indicating that the lipid droplets stabilized by heating
can induce higher apparent viscosity and rheological modulus than
natural lipid droplets, which improves the understanding of the basic
principle of high-quality, low-fat products. However, the application of
citrate esteried potato starch and whey protein in microcapsule wall
materials is still blank.
To avoid the instability and other defects caused by single-wall
materials, in this paper, citric acid was used as an esterifying agent to
modify potato starch, used citrate esteried starch compound whey
protein as wall material, and created lutein microcapsules by spray
drying technology. Medium-chain triglycerides (MCT) are naturally
present in foods such as palm kernel oil, coconut oil, and breast milk and
are one of the sources of dietary fat. MCT is very stable to oxidation at
both high and low temperatures and is often used as an oil phase. Pre-
vious studies have shown that the composition of wall materials
(protein: carbohydrate ratio) and technological conditions are necessary
to obtain stable microcapsules with ideal encapsulation efciency [17].
This study compared and analyzed the morphological structure, physi-
cochemical properties and storage stability of microcapsules prepared
with different proportions of whey protein and citric acid esteried
potato starch. In addition, the feasibility of the whey protein-citrate
esteried starch complex as the carrier of microcapsules was dis-
cussed. Hopefully, it will expand the application of lutein in food,
biology, pharmacy, and other industries and provide a reference for
improving the stability and water dispersibility of other fat-soluble
active ingredients.
2. Materials and methods
2.1. Materials
The potato was purchased from Haoyouduo supermarket (Yangling,
China). Whey protein (purity ≥80 %) was purchased from Bomei
Biotechnology Co., Ltd. (Hefei, China). Nile red (purity ≥98 %) was
purchased from Yuanye Biotechnology Co., Ltd. (Shanghai, China). All
chemicals and reagents utilized were of analytical grade.
2.2. Sample preparation
2.2.1. Starch isolating
Potato starch was prepared according to the method of Zhu & Cui
[18] with slight modications. Firstly, a certain amount of potatoes are
peeled, cleaned, pulped, left to stand, and settled for 4–5 h; the upper
layer slurry was removed, water was added to settle the starch, and
repeated washing and settling until the upper layer slurry was no longer
turbid, the settled starch was taken, dried in a 40 ◦C oven, crushed and
sieved (100
μ
m sieve) to obtain a potato starch sample.
2.2.2. Preparation of citrate esteried potato starch
According to Xie [19], citrate esteried starch was prepared with
some adjustments. First, 100.0 g starch and 30.0 g citric acid (ac-
counting for 30 % of the dry weight of starch) were taken, and citric acid
was dissolved in 60 mL distilled water. Next, the pH was adjusted to 3.5
with 10 mol/L NaOH, and the volume was xed to 120 mL. Next, the
starch and citric acid solution were mixed, left at room temperature for
14 h, and then dried in an oven at 60 ◦C for 8 h. After the water content
reaches 5–10 % (w/w), it is transferred to a silk bottle, and the bottle cap
was unscrewed, reacted in an oven at 130 ◦C for 5 h, washed with
distilled water 3 times, dried, crushed, sieved with 100
μ
m, and stored in
a vacuum bag for later use.
2.2.3. Determination of substitution degree of citrate esteried potato starch
The degree of substitution (DS) of citrate esteried potato starch was
determined by reference to Volkert [20] with some modications. First,
combine 2 g of starch with 20 mL of deionized water and add two drops
of phenolphthalein. Titrate to pink with 0.1 mol/L NaOH solution. Next,
added 25 mL of 0.5 mol/L NaOH solution, shaken at 25 ◦C for 60 min,
and titrated with 0.5 mol/L hydrochloric acids until the solution was
colorless. Using native starch as a control, the degree of substitution was
calculated by the following formula:
DS =162 ×A
100 M− (M−1) × A(1)
A=(V0−V1) × c×M
m×100 (2)
where V
0
is unmodied starch that consumes hydrochloric acid volume
(mL); V
1
is the modied starch that consumes hydrochloric acid volume
(mL); c is the hydrochloric acid concentration (mol/L); M is the molar
mass of substituents (citric acid: 175 g/mol); m is dry basis weight of
W. Zhao et al.
作者：科研～小助
分类：文献
价格：1知币
属性：12 页
大小：3.02MB
格式：PDF
时间：2025-09-01
