Nutritional Effects and Antimicrobial Activity of Kefir (Grains)

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J. Milk Sci. Biotechnol. 2018;36(1):1-13
https://doi.org/10.22424/jmsb.2018.36.1.1
www.ksdst.org J Milk Sci Biotechnol Vol. 36, No. 1 ｜1
REVIEW
Received: March 17, 2018
Re vised : March 21, 2018
Accepted: March 21, 2018
†These authors contributed equally to
this study.
*Corresponding author :
Kwang-Young Song
Dept. of Biological Engineering, Yanbian
University of Science & Technology,
Yanji, China, and Center for One
Health, College of Veterinary Medicine,
Konkuk University, Seoul, Korea.
Tel : +82-2-450-4121
Fax : +82-2-3436-4128
E-mail : drkysong@gmail.com
Copyright © 2018 Korean Society of Milk
Science and Biotechnology.
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ORCID
Ying Shen
0000-0003-3098-3610
Dong-Hyeon Kim
0000-0003-0585-2432
Jung-Whan Chon
0000-0003-0758-6115
Hyunsook Kim
0000-0001-7345-4167
Kwang-Young Song
0000-0002-5619-8381
Kun-Ho Seo
0000-0001-5720-0538
Nutritional Effects and Antimicrobial Activity of Kefir
(Grains)
Ying Shen
1†
, Dong-Hyeon Kim
2†
, Jung-Whan Chon
2
, Hyunsook Kim
3
,
Kwang-Young Song
1,2*
, and Kun-Ho Seo
2†
1Dept. of Biological Engineering, Yanbian University of Science & Technology, Yanji, China
2Center for One Health, College of Veterinary Medicine, Konkuk University, Seoul, Korea
3Dept. of Food & Nutrition, College of Human Ecology, Hanyang University, Seoul, Korea
Abstract
Kefir exhibits antimicrobial activity
in vitro
against gram-positive and gram negative
bacteria, as well as some fungi. The ability of LAB to inhibit the growth of closely related
bacteria is well known. This inhibition of pathogenic and spoilage microbes may be due
to the production of organic acids, hydrogen peroxide, acetaldehyde, diacetyl, carbon
dioxide, or bacteriocins. Lactobacilli are the major contributors to acid production and,
hence, a determining factor in the flavor development in kefir. Lactic acid, proteolytic
activity, and acetaldehyde are the essential flavor compounds in kefir. Both acid and
bacteriocins contribute to the antimicrobial activity of kefir and kefir grains. Kefir is rich
in proteins, calcium, vitamin B
12
, niacin, and folic acid. Many studies have investigated the
benefits of consuming kefir and have shown that it is a natural probiotic, which when
consumed regularly, can help relieve intestinal disorders, promote bowel movement, reduce
flatulence, and improve the overall health of the digestive system. Tibetan kefir, which is
different from traditional kefir, is produced in China. It has been reported to exhibit
antimicrobial activity that is nearly identical to that of traditional kefir. Kefir production
is considered a rapidly growing food industry in China.
Keywords
kefir, kefir grains, nutritional value, antimicrobial activity, kefir’s production
Introduction
Kefir production is mainly based on fermentation of milk with starter kefir culture and
kefir grains looks like little cauliflowers and contains a complex mixture of lactic acid
bacteria, acetic acid bacteria and yeast (Ot1es and Cagindi, 2003; Wojtowski
et al.
, 2003;
Irigoyen
et al.
, 2004; Powell, 2006; Chen
et al.
, 2008; 周
剑
忠
et al.
, 2008; 王
蕊
et al
.,
2009). The complex structure of microflora cause symbiotic relationship is responsible
for fermentation (Maeda
et al.
, 2004;
刘
慧
et al.
, 2005). Thus, the purpose of this review
paper was to suggest the basic information about kefir which had many function for
improving human health. This review contacted kefir’s history, the current industrial
status, kefir’s appearance including the descriptions about kefir grains, kefir’s overall
functions and its production in China. All the materials have been reorganized in the
published literature.
All about Kefir
1. History
The word kefir is derived from the Turkish word ‘keif’ which means ‘good feeling’. Kefir

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is known as a milk beverage of old world food. The drink originated in the Caucasus
Mountains in the former Soviet Union, in Central Asia and has been consumed for
thousands of years (Powell, 2006). The Caucasian people discovered that the fresh milk
carried in leather pouches would occasionally ferment into an effervescent beverage
(Irigoyen
et al.
, 2004). In their countries the kefir until now has been produced
primarily from sheep milk, whereas in Europe its production on a commercial scale is
limited basically to cow milk (Wojtowski
et al.
, 2003).
2. Industrial status
Besides that kefir originally spread through Russia, Eastern Europe, Middle East, the
west Germany, Switzerland, and Northern Europe. Recently, kefir is also popularized in
America, England, Canada, Japan, and so forth. For those countries which did not pay
much attention on kefir, have shown exceeding interests at kefir recently. In particular,
Germany will enlarge both the consumption and production of kefir in the future. In
China, industry of kefir is still at the very beginning step, and the annual yield is less
than 30,000 tons. Most kefir are predominantly imported (王
蕊
et al
., 2009).
3. Kefir and kefir grains
Kefir differs from other fermented dairy products in that it is the product of fer-
mentation of milk in the presence of a mixed group of microorganism confined to a
matrix of discrete ‘kefir grains’, which can be recovered for subsequent fermentation
(Chen
et al
., 2008). Kefir is fermented only by kefir grains and its mother culture, and
kefir grains are the original contributor to kefir’s antimicrobial activity.
Kefir grain, is like small clusters of off-white gelatinous nodules. The grains are
insoluble in water and common solvents, gelatinous, and irregular in size, varying from
0.3∼3.5 cm in diameter. Each grain contains symbiotic consortia of bacteria and yeasts
held together by a matrix of proteins, lipids, and polysaccharides. This symbiosis is
responsible for kefir’s mouthfeel’ s like tangy and stringy, and accounts for many of its
health promoting and medicinal properties (Powell, 2006). These grains can be per-
severed by freezing, lyophilization, and refrigeration (Silva
et al.
, 2009).
4. Kefiran
Kefiran is a water-soluble polysaccharide gel, which constitutes between 24∼25% (m/m)
of the dry weight of the kefir grain. It is a matrix of fibrillar amorphous material. This
fibrillar matrix surrounds the bacteria and yeast in kefir grains, and holds the grains
together (Santos
et al.
, 2003). Kefiran polysaccharide has antibacterial, antimycotic and
antitumour activity (Micheli
et al
., 1999). It is also said that a number of Kefiran-
producing homofermentative LAB have been isolated from kefir grains, including
Lactobacillus
kefir,
Lactobacillus kefirnofaciens
,
Leuconostoc mesenteroides
and
Lac-
tococcus lactis
subsp.
cremoris.
Kefiran has been studied extensively and has demonstrated anti-inflammatory and
immunomodulating properties in animal and human trials. It has also demonstrated
antibacterial and anti-mycotic properties (Diniz, 2003; Maeda
et al.
, 2004).

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5. Health benefits
For kefir is a natural probiotic, it contains live active cultures of normal flora which
is made of very strong strains of microorganisms that help to over take pathogenic
organisms, repopulate the digestive tract and aid in digestion. It also claims that
consuming fermented milk foods can boost the immune system, alleviate symptoms of
diarrhea and chronic constipation, and lower the risk of colon cancer (Ot1es and
Cagindi, 2003).
The microbes in kefir grains are able to produce lactic acid, acetic acid, ethanol,
peptides, and other biologically active components that increase the storage capability
of milk and inhibit the growth of undesirable and pathogenic microbes (Witthuhn
et
al
., 2005). There are data to show that many lactobacilli are capable of producing a
wide range of antimicrobial compounds that may be used in the treatment and
prevention of vaginal infections (Farnworth, 2005).
Some studies refer to kefir’s antimicrobial activity and suggest that the probiotic might
influence the gastrointestinal disorders of humans, such as with ulcers and diarrhea
(Jamuna and Jeevaratnam, 2004).
6. Kefir vs yogurt
Yogurt contains transient beneficial bacteria that keep the digestive system clean and
provide food for the friendly bacteria that reside there. But kefir can actually colonize
the intestinal tract, a feat that yogurt cannot match. Kefir contains several major strains
of friendly bacteria not commonly found in yogurt,
Lactobacillus Caucasus,
Leu-
conostoc
,
Acetobacter
species, and
Streptococcus
species. Because the curd size of kefir
is smaller than yogurt, it is also easier to digest, which makes it a particularly excellent,
nutritious food for babies, the elderly and people experiencing chronic fatigue and
digestive disorders.
7. Production of kefir
Kefir can be made from any type of milk, cow, goat or sheep, coconut, rice or soy.
Although it is slightly mucous forming, the mucous has a "clean" quality to it that creates
ideal conditions in the digestive tract for the colonization of friendly bacteria.
There are several methods of producing kefir (Ot1es and Cagindi, 2003). Commonly
traditional and industrial processes are used and also food scientists are currently studying
modern techniques to produce a kefir with the same characteristics as those found in
traditional kefir.
Here are the two basic types of processes:
1) Traditional process
the traditional method of kefir making involves the direct addition of kefir grains to
milk, which has been pasteurised and cooled to between 200℃ and 250℃. Then, fer-
mented in 18∼24 hours at 20∼250℃ (room temperature). After this, the grains are
removed by filtering with a sieve and can be dried at room temperature and kept at
cold surroundings for being used in the next inoculation. Kefir is stored at 40
o
C for a

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time then is ready for consumption. The traditional process of kefir is shown in Fig. 1.
2) Industrial process
this method is almost the same as traditional process. First, to homogenize the
milk to 8% dry matter and held by heat treatment at 90∼95
℃
for 5∼10
minutes. Then to cool at 18∼24
℃
and inoculated with 2∼8% kefir cultures in
tanks. It costs 18∼24 hours to ferment. The coagulum is separated by pomp
and distributed in bottles. After maturing at 12∼14
℃
or 3∼10
℃
for 24 hours,
kefir is stored at 4
℃
. The industrial process of kefir is shown in Fig. 2
(Ot1es
S and Cagindi, 2003).
The optimal conditions for kefir’s fermentation has been proved to be: fermenting
temperature 23℃, incubating quantity 3%, time requirement 48h, concentration 12%.
Incubating temperature is the primary factor which affects fermentative activity.
Secondly, the milk concentration. Thirdly, the quantity of incubating kefir grains. At last,
incubating time makes the least influence on fermentative activity (
刘慧
et al
., 2005)
.
Functions of Kefir
1. Physiological function of kefir
Owing to the probiotic microbial communities are different from the common yogurt,
the physiological functions of its products are superior than the common yogurt. Kefir
is rich in highly digestible lactoprotein and milk fat, in which probiotic microbial com-
Fig. 1. The traditional process of kefir.

Nutritional Effects and Antimicrobial Activity of Kefir (Grains)
www.ksdst.org J Milk Sci Biotechnol Vol. 36, No. 1 ｜5
Fig. 2. The industrial process of kefir.
munity hydrolyzes most of lactose in milk into human benefited L-lactic acid, with very
little D-lactic acid formed. It claims that kefir contains 2∼5% D-lactic acid, which is
further lower than that of common yogurt (contains about 25∼60% lactic acid). Since
human body is lack of metabolic enzyme of lactate, ingesting D-lactic acid is more easy
to suffer a acidic blood disease.
Therefore, kefir is a good diet for lactose intolerant individuals that have the inability
to digest significant amounts of lactose that is the predominant sugar of milk (Ot1es
S and Cagindi, 2003).
Meanwhile, with the function of L-lactic acid, it also improves the absorbability of
calcium, phosphorus, and iron. In addition, kefir is rich in water soluble vitamin B, like
vitamin B
1
, vitamin B
2
, vitamin B
6
, vitamin B
12
, niacin, and folic acid. As a result, kefir
is not only brings a high nutritional value, but also contribute to a better health and
increasing longevity (王
蕊
et al
., 2009).
2. Other beneficial properties
1) Impacts on immune system
Researches also claimed about their curative properties and consumed that fermented
milk foods can boost the immune system, alleviate symptoms of diarrhea and chronic

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constipation, and lower the risk of colon cancer have been popular, along with the
perception that commercial yogurt and kefir are inferior to those fermented at home
from natural starters (Lopitz-Ostoa
et al.
, 2006). Probiotics found in kefir have sti-
mulating effects on the immune system by improving phagocytosis and by increasing
the numbers of T-lymphocytes and NK cells. They also have an indirect effect on the
immune system by forming bioactive peptides in the process of fermentation (Heyman,
2000; Sanders, 2000).
2) Antitumor activity
Several studies have investigated the antitumor activity of kefir and polysaccharides
form kefir grain (Cevikbas
et al.,
1994; Furukawa
et al.
, 1990). And recent researches
demonstrated that kefir has a better function of antiatheroscloresis and antidiabetics,
and has the curative properties for tuberculosis. Besides, kefir contains capsular poly-
saccharide which inhibit the reproduction of cancer cells, so that reduce the incidence
of cancer.
3) Microorganisms’growing inhibition
Kefir can also decrease contents of serum cholesterol, strengthen functions of liver and
gall. Improving the functions of immune system and anti-aging. viable organism in kefir
grains forcefully inhibit production of such bacteria, like
Mycobacterium
tuberculosis,
Escherichia coli
,
Shigella
,
Salmonella
. Therefore, frequently consumption of kefir can
maintain a superiority of probiotic community within human’s gastrointestinal tract.
“ Revolution in bowels” mentions that “intestinal disease is the root of all diseases”. A
healthy body should begin with healthy intestines. Consequently, the consumption of
kefir in a frequent way, a superiority of probiotic in intestines can be retained, and
reduce incidence of intestinal diseases, eventually obtain a healthy body and the aim
of longevity.
3. Nutritional values
The composition of kefir is variable and not well defined (Zubillaga
et al.
, 2001). It
depends on the source and the fat content of milk, the composition of the grains or
cultures and the technological process of kefir. The chemical composition of kefir is
shown in Fig. 3.
The nutrient composition of kefir is similar to that of milk, in addition to beneficial
bacteria and yeast, kefir contains vitamins, minerals and essential amino acids that help
the body with healing and maintenance functions. With kefir containing more vitamins
B
1
, B
2
and folic acid, kefir is also rich in vitamin K and amino acids and is an excellent
source of biotin, a B vitamin that aids in the assimilation of the other B vitamins. The
proteins in kefir are partially digested and are, therefore, more easily utilized.
Tryptophan, one of the essential amino acids abundant in kefir, is well known for its
relaxing effect on the nervous system. Kefir also offers an abundance of calcium and
magnesium, which are important minerals for a healthy nervous system. The high
phosphorous content contributes to the utilization of carbohydrates, fats, and proteins

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www.ksdst.org J Milk Sci Biotechnol Vol. 36, No. 1 ｜7
Fig. 3. The chemical composition and the nutritional values of kefir.
by the body for cell growth, maintenance and energy (Saloff-Coste, 1996).
Kefir is a good source of essential amino acids, vitamins, and minerals, which helps
maintenance chemistry in our body (Fig. 3).
The numerous benefits of B vitamins are regulation of the kidneys, liver and nervous
system to helping relieve skin disorders, boost energy and promote longevity (Ot1es and
Cagindi, 2003). Propionibacteria may be added to the kefir grains to increase the
vitamin B
12
concentration of the beverage. This is beneficial as the presence of vitamin
B
12
in milk decrease as much as 95% during lactic acid fermentation. The micro-
organisms in kefir do not synthesize vitamin B
12
, but they stimulate its production in
mixed culture in the presence of propionic acid bacteria. Van Wyk (2002) reported
increases of vitamins B
12
in kefir enriched with
Propionibacterium freudenreichii
subsp.
shermanii
.
Antimicrobial Activity of Kefir
1. Microorganism living on kefir grains
Kefir and sphingomyelin isolated from the lipids in kefir have been reported to
stimulate the immune system in both
in vitro
and
in vivo
studies (Osada
et al.
, 1994;
Zacconi
et al.,
1995).
Kefir possesses antimicrobial activity
in vitro
against a wide variety of Gram-positive
and Gram-negative bacteria, as well as some fungi (Garrote, 2000).
Differences in the genus, species or strain of probiotic bacteria can contribute to
differences in traits such as stability, enzyme expression, carbohydrate fermentation
patterns, acid production, and colonizing ability. The composition of kefir varies drama-

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Fig. 4. Kefir grain. Off-white, looks like pieces of
coral or small clumps of cauliflower.
Fig. 5. Microorganism perched on kefir grains
culture medium, containing a complex mixture of
microorganisms.
tically depending on a variety of factors, including the source of the milk, its fat content
and the composition of the grains or starters.
Kefir grains include LAB (
Lactobacilli, lactocci, Leuconostocs
), yeasts, acetic acid
bacteria and possibly other microorganisms. The predominant
Lactobacilli
in kefir
grains are
L. paracasei
subsp.
paracasei, L. acidophilus
,
L. delbrueckii
subsp.
bulga-
ricus, L. plantarum
and
L. kefiranofaciens
. These strains account for 90% of the
population in the grains, but only 20% of the
Lactobacilli
in the final fermented
beverage. The remaining 80% of these LAB consists of
L. kefir.
Here is the Table for microorganisms associated with kefir and kefir grains:
ž
Lactic acid bacteria
ž
Enterococcus durans
ž
Lactobacillus kefiranofaciens
ž
Leuconostoc mesenteriodes
ž
Streptococcus salivarius
ž
Acetic acid bacteria
ž
Yeasts
ž
Candida pseudotropicalis
ž
Mycelial fungi
Some coliforms are actively inhibited by kefir microorganisms, and pathogenic bacteria
such as
Shigella
and
Salmonella
do not grow when they are introduced to kefir. Of all
the kefir starter microbial components, the microphilic homofermentative lactococci
and acetic acid bacteria are the most active against coliforms. The microbes in kefir
grains are able to produce lactic acid, acetic acid, ethanol, peptides, and other
biologically active components that increase the storage capability of milk and inhibit
the growth of undesirable and pathogenic microbes.
Van Wyk (2001) showed that kefir possesses an inhibitory activity against
Staphy-
lococcus aureus, Bacillus cereus, Escherichia coli
,
Clostridium tyrobutyricum
and
Lis-
teria monocytogenes
. Studies have also indicated that yeasts such as
Torulaspora
, when

Nutritional Effects and Antimicrobial Activity of Kefir (Grains)
www.ksdst.org J Milk Sci Biotechnol Vol. 36, No. 1 ｜9
separated from kefir, possess pronounced antimicrobial activiry against coliforms
(Powell, 2006).
The exact cause of the inhibition is not known, but may be due to the antagonistic
action of various species of LAB (Lactic Acid Bacteria). Lactic acid bacteria are also
capable of preventing the adherence, establishment, replication, and pathogenic action
of certain enteropathogens. The precise mechanism of this antagonistic activity is not
clear, but may include the activity of lactic acid or volatile acids, hydrogen peroxide,
carbon dioxide, acetaldehyde and diacetyl, or bacteriocin and bacteriocin-like pro-
ducts. Supposedly, some inhibitory compounds of the kefir beverage, such as bac-
teriocins, hydrogen peroxide, and organic acids might be responsible for killing patho-
genic microorganisms.
In addition, kefir might also promote competitive adhesion to the gastrointestinal
epithelium surface (Ot1es and Cagindi, 2003).
Lactobacillus
isolated from kefir showed
antimicrobial activity against
Enterobacteria
and verified that ingestion of kefir spe-
cifically lowered microbial populations of Enterbacteriaceae and
Clostridia
(Powell, 2006).
2. Antimicrobial activity of kefir (grains)
LAB must survive in the digestive system after they are consumed in order to produce
any beneficial effects. It has been shown that
Lactobacillus delbrueckii
subsp.
bulgaricus
consumed in fermented milk products like yogurt and kefir do survive the
passage through the upper gastrointestinal tract. Probiotics have been effective in the
treatment of people with inadequate lactose digestion, as they convert the lactose in
the lactic acid, rendering the milk they ferment almost lactose-free. Research has
shown that probiotic can contribute to the general health of their host by resisting
colonization of the digestive system by harmful microorganisms, contributing to the
nutrition of the host, and affecting immunomodulation.
A decrease in the pH of the kefir beverage is caused by the accumulation of organic
acids, primarily lactic acid and acetic acid, produced as major end-products of
carbohydrate metabolism by LAB. Accumulation of lactic acid and a subsequent
decrease in pH results in a broad-spectrum inhibitory activity against Gram-positive
and Gram-negative bacteria.
The undissociated forms of lactic and acetic acid penetrates the microbial cell
membrane. This results in acidification of the cytoplasm and the formation of inhibi-
tions, especially against enzymes, by salt excesses. At a higher intracellular pH these
acids dissociate to produce hydrogen ions, which interfere with important metabolic
functions such as oxidative phosphorylation and substrate translocation. The antimi-
crobial effect of lactic or acetic acid depends on the pKa value of the acid, as well as
the pH of the external environment. These acids are known to inhibit
E. coli
and
B.
cereus
. At a pH 5.0, acetic acid inhibits the growth of
Salmonellae typhimurium.
A
synergism between lactic and acetic acid has been reported for the inhibition of
E. coli
and
Salmonella
spp. (Garrote
et al.
, 2000). Lactic acid is a stronger acid than acetic acid
and in well-buffered foods with a pH of 4∼6, acetate has a stronger antimicrobial effect
as a greater portion of the acid is undissociated.

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Brown sugar was the most effective carbohydrate source with antimicrobial action,
mainly against
C. albicans
, for kefir grains promoted the hydrolysis of non-reducing
sugars, which are converted into organic acids and substances capable of producing
inhibition halos with pathogenic microorganisms (Yuksekdag
et al
., 2004).
Kefir’s Research and Production in China
1. Tibetan kefir
In China, there is such a kind yogurt that the production is very resemble to that of
kefir’s. People immerse Tibetan kefir grains in milk, after acidification of the milk,
separate the grains. Also, it claims that long time drinking Tibetan kefir beverage can
boost people’s immune system, complement vitamins, retard aging, allay tiredness,
particularly good for people who suffering a gastrosia, or nephropathy. This kind
Tibetan kefir looks very similar to kefir grains. They are both off-white, colloidal lump,
and there lives various microorganisms on the surfaces. Research has shown that
compared microbial community structures of kefir and Tibetan kefir by using
PCR-DGGE, bacteria community showed a 78∼84% similarity among different Tibetan
kefir, and 50∼70% among kefir from different regions. DGGE profiles of yeast indicated
80∼92% similarity of yeast community among 3 Tibetan kefirs, and a 50∼75% similarity
among kefir from different regions (周
剑
忠
et al.
, 2008).
According to Fig. 8 and Fig. 9, it is seen that compared with kefir grain, the
microorganism density of the outer surface of Tibetan kefir grain is larger.
2. Development of various kefir’s products and outlook of kefir’s research in China
Kefir is an amazing yogurt, which is the secret of longevity in the Caucasus residents,
because of its unique nutritional and health function abnormalities prevalent in foreign
countries. However, kefir production in China is severely hampered. The reason is that
kefir ferment on high-priced imports and the foreign agent produced by fermentation
of kefir flavor and texture are not suitable for domestic consumption habits.
China’s large population, the demand for fermented health drinks straight up, while
China’s current annual sales of kefir beverages is less than small countries such as
Sweden and Finland, mainly due to kefir ferment rely on imports, prices high, a single
species and fermentation, the impact of active instability.
There are many companies produced new kefir fermentation agent industrialization,
which both lowered the price of kefir and produced high quality that can be com-
parable to foreign products. Plus kefir can be easily made at home. Therefore, an
effective solution to the foreign monopolies, import prices are too high and fermented
beverages are not suitable for Chinese tastes and so on. Consequently, it will promote
the industrialization of kefir in China.
Conclusion
Kefir’s high nutritional values, containing about tryptophan, minerals, and vitamins,

Nutritional Effects and Antimicrobial Activity of Kefir (Grains)
www.ksdst.org J Milk Sci Biotechnol Vol. 36, No. 1 ｜11
Fig. 6. Kefir grains from Belgium. Fig. 7. Tibetan kefir grains from Tibet.
Fig. 8. Outer surface of Tibetan kefir grain
(×3,000).
Fig. 9. Outer surface of kefir grain (×3,000).
which help human body get rid of many diseases. Such as intestinal diseases, cancer,
etc. Due to the microorganisms living on the surface of kefir grain, kefir possesses an
inhibitory activity against
Staphylococcus aureus, Bacillus cereus, Escherichia coli
,
Clostridium tyrobutyricum
and
Listeria monocytogenes
. Meanwhile, studies have also
indicated that yeasts such as
Torulaspora
, when separated from kefir, possess pro-
nounced antimicrobial activity against coliforms, as well as some fungi, so as to lower
the risk of colon cancer. Therefore, it is recommended to consume kefir for being in
good shape. As the industrialization of kefir will be promoted in China, more and more
Chinese can benefit from this nutritional food as well.
Acknowledgment
This research was supported by Basic Science Research Program through the National
Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-
2017R1D1A1B03035427).
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