Content uploaded by Monika Selvavinayagam
Author content
All content in this area was uploaded by Monika Selvavinayagam on Sep 05, 2023
Content may be subject to copyright.
Content uploaded by Suneel Kumar
Author content
All content in this area was uploaded by Suneel Kumar on Aug 02, 2023
Content may be subject to copyright.
_____________________________________________________________________________________________________
++ Ph.D. Research Scholar;
*Corresponding author: E-mail: kumaranuj9497@gmail.com;
Int. J. Environ. Clim. Change, vol. 13, no. 9, pp. 2531-2538, 2023
International Journal of Environment and Climate Change
Volume 13, Issue 9, Page 2531-2538, 2023; Article no.IJECC.103646
ISSN: 2581-8627
(Past name: British Journal of Environment & Climate Change, Past ISSN: 2231–4784)
A Comprehensive Review on Millets: A
Potential Source of Energy and
Nutrients for Health
Suneel Kumar a++, Rathod Sridhar b++, S. Monika c++,
Anuj Kumar d++*, Bhayankar e, Megha Raghavan f++,
Himanshu Tiwari g++, Amit Kumar h++,
Shubham Singh i++ and Rishabh Yadav i++
a Department of Soil Science and Agricultural Chemistry, Sardar Vallabhbhai Patel University of
Agriculture and Technology, Meerut, (U.P.) 250110, India.
b Department of Agronomy, School of Agriculture Science, Nagaland University, Medziphema 797106,
India.
c Department of Genetics and Plant Breeding, Anbil Dharmalingam Agricultural College and Research
Institute, TNAU, Trichy, India.
d Department of Genetics and Plant Breeding, Sardar Vallabhbhai Patel University of Agriculture and
Technology, Meerut, (U.P.) 250110, India.
e Department of Agronomy, Chandra Shekhar Azad University of Agriculture and Technology, Kanpur,
(U.P.) 208002, India.
f Department Fruit Science, College of Horticulture and Forestry, Central Agricultural University,
Pasighat, Arunachal Pradesh 791102, India.
g Department of Agronomy, Sardar Vallabhbhai Patel University of Agriculture and Technology,
Meerut, (U.P.) 250110, India.
h Department of Fruit Science, Sardar Vallabhbhai Patel University of Agriculture and Technology,
Meerut, (U.P.) 250110, India.
i Department of Agricultural Extension Education, Sardar Vallabhbhai Patel University of Agriculture
and Technology, Meerut, (U.P.) 250110, India.
Authors’ contributions
This work was carried out in collaboration among all authors. All authors read and approved the final
manuscript.
Article Information
DOI: 10.9734/IJECC/2023/v13i92487
Open Peer Review History:
This journal follows the Advanced Open Peer Review policy. Identity of the Reviewers, Editor(s) and additional Reviewers,
peer review comments, different versions of the manuscript, comments of the editors, etc are available here:
https://www.sdiarticle5.com/review-history/103646
Kumar et al.; Int. J. Environ. Clim. Change, vol. 13, no. 9, pp. 2531-2538, 2023; Article no.IJECC.103646
2532
Received: 26/05/2023
Accepted: 28/07/2023
Published: 01/08/2023
ABSTRACT
Millets, Cereals and grains, are essential for providing appropriate nutrients and have been shown
to be beneficial effect for disorders of lifestyle. The society's knowledge of nutrition and health care
research substantiates the potential of photochemicals, such as polyphenols and dietary fibers, on
their health beneficial properties, so there is no need to search for newer sources of energy and
other natural and nutritional material with the desired functional characteristics. It is a crucial staple
food crop in India, especially for low-income families. Its value in terms of nutrition is widely known
because to its high content of phenolic compounds (0.03%–3%), dietary fibre (18%), and calcium
(0.38%).
Keywords: Millets; energy sources; nutritional value; health importance.
1. INTRODUCTION
The word “Millets” (A Nutritive Crop) is beneficial
to numerous grass crops whose seeds are
picked for human food or animal feed [1].
Millet is most important cereal after rice, sorghum
and wheat and it is a most necessary food for
thousands of years in many parts of Africa and
India. Lots of persons around the world mostly
persons who alive in hot, tropical environments,
trust deeply on millets as a sustenance source.
As they can bloom in challenging environmental
conditions like little precipitation, millets are a
main meal in many developing states. For lots of
publics living in arid zones, millet helps as their
major source of protein and energy. Millet is
known to have a variety of nutritional and
therapeutic uses [2,3].
Millets are extremely nutritious yet are frequently
overlooked as a main source of food, mostly
because people are unaware of them. Millets
have increased abundant significance in the
realm of biomedical study, however, as a result
of growing indication that they have helpful things
on human fitness [4].
Millets are slight, round grains with a high
nourishing content that are mainly made up of
crude fibre (2–7%), protein (7–11%), and fat
(1.5–5%). Moreover, millets are free of gluten
and high in zinc, magnesium, iron, calcium, and
vitamin B [5].
The United Nation officially recognizes 2023 as
the "International Year of Millets" in response to
India's request. The "National Year of Millets"
has previously been celebrated in India during
2018. The statements seek to increase the
community's understanding of millets' importance
for food security and nourishment as well as to
build up their high-quality, environmentally
friendly production.
Table 1. Types of millets and its name
Millets
Common name
Scientific name
Finger Millets
Ragi
Eleusine coracana
Foxtail Millets
Kangni
Setaria italica
Sorghum Millets
Jowar
Sorghum bicolor
Pearl Millets
Bajra
Pennisetum glaucum
Proso Millets
Chena
Panicum miliaceum
Kodo Millets
Kodon
Paspalum scrobiculatum
Barnyard Millets
Sanwa
Echinochloa crusgalli
Little Millets
Kutki
Panicum sumatrense
Review Article
Kumar et al.; Int. J. Environ. Clim. Change, vol. 13, no. 9, pp. 2531-2538, 2023; Article no.IJECC.103646
2533
Table 2. Millets and its nutritional composition: (mg/100 g)
Millets
Protein
Fat
Fibre
Minerals
Carbohydrates
References
Finger Millets
7.3
1.3
11.5
2.7
72.05
Himanshu et al. [6].
Foxtail Millets
11.2
4.0
6.7
3.3
63.2
Jaybhaye et al. [7].
Sorghum Millets
10.4
3.1
2.0
1.68
70.7
Tiwari et al. [8]
Pearl Millets
11.8
4.8
2.3
2.2
67.0
Saini et al. [9].
Proso Millets
11.0
3.5
8.5
1.9
56.1
Das et al. [10].
Kodo Millets
8.35
1.5
5.2
3.3
65.6
Bunkar et al. [11].
Barnyard Millets
10.5
3.6
12.6
2.0
68.8
Ugare et al. [12].
Little Millets
8.92
2.5
6.39
1.72
65.5
Rao et al. [13].
Fig. 1. Millets and its nutritional composition: (mg/100 g)
Millets typically come in seven different varieties,
each with unique colours, shapes, sizes, and
growing regions. The Poaceae family includes
these small-seeded, spherical cereals, which are
the earliest and most likely the first cereal grain
that humans have used for domestic purposes
[14]. The grain with the sixth-highest yield in the
world is millet. India is the world's second-largest
exporter of millets and its primary producer. The
Foreign Agricultural Service of the United States
Department of Agriculture reports that as of
February 2023, India produced 39% of the millets
grown globally for the year 2022. The Nutritional
compositions of millets have been given in Table
2 and depicted in Fig. 1.
2. FINGER MILLETS
Ragi, commonly known as finger millets, is a
crucial staple food for people from low socio
economic backgrounds and those who suffer
from metabolic illnesses like diabetes and
obesity. Rice or wheat can be substituted with
finger millet, which is regarded as a healthy,
nutritious food. They are a good source of
minerals, dietary fibre, protein, and carbs [15]. Its
great ability to store food and nutritional value
make it important [16].
It is a good laxative and helps to avoid
constipation because of its high fibre content. It
contains a lot of calcium, finger millet is beneficial
for young children, the elderly and pregnant
women. Additionally, it is highly beneficial for
nursing mothers as it helps in the production of
adequate breast milk [17].
3. FOXTAIL MILLETS
Foxtail millet is a generally farmed and
consumed cereal that is important to the
worldwide economy, particularly in India, China,
and other areas of Asia, North Africa, and the
Americas.
0
10
20
30
40
50
60
70
80
Finger
Millets Foxtail
Millets Sorghum
Millets Pearl
Millets Proso
Millets Kodo
Millets Barnyard
Millets Little
Millets
Millets and its Nutritional Composition: (mg/100 g)
Protein Fat Fibre Minerals Carbohydrates
Kumar et al.; Int. J. Environ. Clim. Change, vol. 13, no. 9, pp. 2531-2538, 2023; Article no.IJECC.103646
2534
It is a cereal grain that is a member of the Setaria
genus and the Panicoideae subfamily of the
Poaceae family [18]. The synthesis of the
neurotransmitter acetylcholine, which transmits
signals between muscles and nerves, is aided by
foxtail millet's gluten-free, high protein, low
carbohydrate composition. Foxtail millet keeps
up the stamina, keeps you stronger, and
increases immunity to combat numerous
diseases that may be lurking because it is a
nutritional powerhouse.
4. SORGHUM MILLETS
Sorghum is one of the most significant crops in
terms of cultivated land and global production.
Sorghum is a grain that is both gluten-free and
rich in nutrients and chemical compounds that
have physiological effects. The fifth-largest
cereal crop in the world, sorghum is widely grown
as a grain, sweet, forage, low-lignin, and
biomass crop. It can grow in a variety of climates.
It is a crop that can be grown in arid
environments since it is heat- and drought-
tolerant. [19]. Sorghum includes iron, calcium,
fibre, protein, and wax policosanols, all of which
have health advantages, including lowering
cholesterol levels [20]. Sorghum's abundance of
tannins and polyphenols provides both
anticancer and antimutagenic effects [21].
5. PEARL MILLETS
Pearl millet is a resistant cereal crop compared
to wheat and rice, is cultivated in places with
deficient rainfall. It is the sixth-most important
grain in the world, and semiarid parts of Asia and
Africa mostly depend on it for food [22].Pearl
millet which accounts for 40% of worldwide
production [3]. Over 95% of pearl millets are
produced in developing nations, with India
producing the most with 9.8 million hectares
worldwide [23]. Pearl millet's high oil content (4–
9%) allows for easy storage of the grain at low
temperatures and low levels of moisture.
Additionally, there are considerable amounts of
unsaturated fatty acids, folate, copper, zinc, iron,
magnesium, calcium, vitamin B complex, and
other minerals [8].
6. PROSO MILLETS
Proso millet is definitely a climate-smart, gluten-
free, small-grain cereal that is good for both
people and the environment. Protein and
vitamins are found in proso millet. It is
traditionally used as a restorative dish,
particularly after childbirth or illness (Jana
Kalinova, 2007).Niacin, a form of Vitamin B3, is
what causes the Pellagra illness, which proso
millet is helpful in treating. Niacin is highly
concentrated in proso millet. Pellagra is a skin
condition that results in dry, scaly, and rough skin
[24]. Proso millet has a lot of benefits when used
as human food. Proso millet has various specific
properties (such as drought tolerance and a short
growth season) that make it a suitable rotational
crop for dry land farming systems based on
winter wheat. When employed in a two-year
wheat/summer fallow cropping system, proso
millet offers the most economically advantageous
production strategy [10].
7. KODO MILLETS
Kodo millet has been suggested that it originally
originated in India. Kodo millet is considered to
have first been domesticated around 3000 years
ago [25]. A traditional food that promotes weight
loss and has a taste akin to rice is kodo millet. It
is easily absorbed and abundant in
phytochemicals and antioxidants, which help to
prevent a number of diseases associated with a
sedentary lifestyle [17]. Kodo millet can be
consumed regularly by postmenopausal women
who exhibit symptoms of cardiovascular disease,
such as high blood pressure and excessive
cholesterol. It has higher antioxidants, which
guard against oxidative stress and maintain
stable blood sugar levels and diabetes. Asthma,
migraines, high blood pressure, heart attacks,
atherosclerosis, and diabetic heart disease can
all be treated with kodo millet [10].
8. BARNYARD MILLETS
In warm, temperate areas all around the world,
the ancient millet crop known as barnyard millet
(Echinochloa species) is grown. In Asia,
especially in India, China, Japan, and Korea, it is
extremely popular [26]. It is the fourth most
widely grown minor millet and provides food
security to many poor individuals worldwide
[27].Although it is also fed to animals, most
barnyard millet is grown for human consumption.
Echinochloa frumentacea (Indian barnyard millet)
and Echinochloa esculenta (Japanese barnyard
millet), which are both cultivated and wild
species, are two of the most popular types of
barnyard millet [28]. Barnyard millet is a short-
lived crop that can tolerate a variety of biotic and
abiotic stresses and grow in unfavorable
environmental circumstances with essentially
little input.
Kumar et al.; Int. J. Environ. Clim. Change, vol. 13, no. 9, pp. 2531-2538, 2023; Article no.IJECC.103646
2535
Fig. 2. Different types of millets
Sources: Tiwari et al., 2023
9. LITTLE MILLETS
Little millet is a unique minor cereal that is grown
extensively in the tropics and is a staple diet for
some low-income groups around the world. Little
millet provides a comparable source of protein,
fat, carbohydrates, and crude fibre to other
cereals like rice and wheat, and it also offers
minerals and vitamins. It also includes
phytochemicals including flavonoids, phytate,
phenolic acids, and tannins [29]. Little millet may
be less nutrient-rich than other grains despite its
small size. It has significant amounts of B
vitamins as well as many minerals, including as
calcium, iron, zinc, and potassium. This also
gives the body the kinds of essential fats that
promote weight loss. It also has the benefit of
having a high fibre content, which makes it an
excellent alternative to rice in Pongal or even
Kheer [20].
10. HEALTH BENEFITS OF MILLETS
Millets have a number of nutritional advantages
that can help people stay healthy, including
lowering blood pressure, decreasing the risk of
heart disease, preventing cancer and
cardiovascular diseases, and decreasing the
occurrence of tumours, among other things.
Increasing the time it takes for the stomach to
empty and providing the intestines with some
roughage are two additional health benefits [30].
An alkaline-forming food is millet. To attain
optimal health, meaning when it interacts with
digestive enzymes, an alkaline-based diet is
frequently advised. The calming alkaline
properties of millet aid in preserving the body's
optimal pH balance, which is essential to ward off
infections [31]. In many African and Asian
nations, millets which are high in phytic content
and minerals-are a staple food of all the grains,
millet has the cheapest agricultural production
costs [32].
Saleh et al. [33] studied the processing,
nutritional value, and potential health advantages
of millet grains. The bioavailability of
micronutrients is improved by processed food.
They are both very nutritious and include many
elements that are good for human health.
Postmenopausal women usually suffer from
symptoms of cardiovascular disease, such as
increased blood pressure and cholesterol levels.
Therefore, including Kodo millet in a person's
regular diet is quite beneficial for maintaining
great health [34].
The high protein content of millet supports
children's healthy growth and development.
Millet's level of calcium stimulates the
development of bones and lowers the risk of
bone fractures. Additionally, it has high-quality
iron, which helps with anemia treatment. Millet's
gluten-free status benefits those with celiac
disease and, consequently, those who are gluten
sensitive [24].
Kumar et al.; Int. J. Environ. Clim. Change, vol. 13, no. 9, pp. 2531-2538, 2023; Article no.IJECC.103646
2536
Although millets should be a regular part of our
diet due to their many nutritious advantages, the
majority of informed people have never ever
heard of millets or their advantages. Foods
devoid of fibre are causing serious health
problems for people all over the world [35,36]. By
incorporating millets into a person's normal diet
and avoiding refined foods like rice, wheat,
processed meats, refined flours, refined oils, and
ready-to-eat foods, all lifestyle diseases can be
eradicated, according to prior research findings
[24]. Millets are high in phenolic acids, phytates,
and tannins, which are antinutrients that lower
the incidence of colon and breast cancer. Millets
can lower blood sugar levels by enzymatically
hydrolyzing complex carbohydrates in
hyperglycemia. The aldose reductase enzyme
benefits in reducing sorbitol formation and lowers
the chance of developing diabetes (Mishra et al.
2002).
Magnesium, which lowers the risk of heart attack,
is abundant in millets. A good source of
phytochemicals that lower cholesterol and help
prevent heart disease is millets [30].
Fibre is present in millet, which promotes healthy
digestion and helps to control bowel habits.
Additionally, it possesses prebiotic qualities that
aid in the development of probiotic bacteria in the
micro biome by enhancing immune function all
around and digestion, this has positive health
effects [37].
11. CONCLUSION
Consumers are now easily drawn to fast food
and bakeries, which has led to a lot of health
problems. Therefore, the current study aims to
emphasize the value of healthy food and
encourage people to adopt millets as a healthy,
nourishing food into their regular diet. The use of
millets, an old treasured grain-like seed, in our
daily diet has numerous health benefits. Most
civilized people have never even heard of millet,
much less are aware of its nutritional
advantages. However, one of our distant
ancestors' best-kept secrets was millet.
Therefore, it can be said that people need to
know about millets and their health advantages
and consume millets to lead a healthy and happy
life.
COMPETING INTERESTS
Authors have declared that no competing
interests exist.
REFERENCES
1. Thapliyal V, Singh K. Finger millet:
Potential millet for food security and power
house of nutrients. International or
Research in Agriculture and
Forestry. 2015;2(2).
2. Obilana AB, Manyasa E. Millets. In: P. S.
Belton and J. R. N Taylor (Eds.). 2002;
177–217.
3. Yang X, Wan Z, Perry L, Lu H, Wang Q,
Hao C, Li J, Xie F, Yu J, Cui T, Wang T, Li
M, Ge QH. Early millet use in northern
China. Proc. Nat. Acad. Sci. USA. 2012;1-
5.
4. Rao BR, Nagasampige MH, Ravikiran M.
Evaluation of nutraceutical properties of
selected small millets. Journal of
Pharmacy and Bioallied Sciences. 2011;
3(2):277–279.
5. Majid A, Priyadarshini CG, P. Millet
derived bioactive peptides: A review on
their functional properties and health
benefits. Critical Reviews in Food Science
and Nutrition. 2020;60(19):3342-3351.
6. Himanshu K, Sonawane SK, Arya SS.
Nutritional and nutraceutical properties of
millets: A review. Clinical Journal of
Nutrition and Dietetics. 2018;1(1):1-10.
7. Jaybhaye RV, Pardeshi IL, Vengaiah PC,
Srivastav PP. Processing and technology
for millet based food products: A
review. Journal of Ready to Eat Food.
2014;1(2):32-48.
8. Tiwari H, Naresh RK, Bhatt R, Kumar Y,
Das D, Kataria SK. Underutilized nutrient
rich millets: Challenges and solutions for
india's food and nutritional security: a
review. International Journal of Plant & Soil
Science. 2023;35(2):45-56.
9. Saini S, Saxena S, Samtiya M, Puniya M,
Dhewa T. Potential of underutilized millets
as Nutri-cereal: An overview. Journal of
Food Science and Technology. 2021;1-13.
10. Das S, Khound R, Santra M, Santra DK.
Beyond bird feed: Proso millet for human
health and environment. Agriculture. 2019;
9(3):64.
11. Bunkar DS, Goyal SK, Meena KK,
Kamalvanshi V. Nutritional, functional role
of Kodo millet and its processing: A
review. International Journal of Current
Microbiology and Applied Sciences.
2021;10(01):1972-1985.
12. Ugare R, Chimmad B, Naik R, Bharati P,
Itagi S. Glycemic index and significance of
Kumar et al.; Int. J. Environ. Clim. Change, vol. 13, no. 9, pp. 2531-2538, 2023; Article no.IJECC.103646
2537
barnyard millet (Echinochloa frumentacae)
in type II diabetics. Journal of Food
Science and Technology. 2014;51(2):
392-395
13. Dayakar Ra B, Bhaskarachary K, Arlene
Christina GD, Sudha Devi G, Vilas AT,
Tonapi A. Nutritional and health benefits of
millets. ICAR_Indian Institute of Millets
Research (IIMR) Rajendranagar,
Hyderabad. 2017;2.
14. FAO World Food and Agriculture -
Statistical Year book; FAO: Rome, Italy;
2020.
15. Mathanghi SK, Sudha K, Functional and
phytochemical properties of finger millet
(Eleusine coracana) for health.
International Journal of Pharmaceutical
Chemical and Biological Sciences. 2012;
2(4):431-438.
16. Shashi BK, Sunanda S, Shailaja H,
Shankar AG, Nagarathna TK.
Micronutrient composition, antinutritional
factors and bioaccessibility of iron in
different finger millet (Eleusine coracana).
Karnataka Journal of Agricultural
Sciences. 2007; 20(3):583-585.
17. Ambati K, Sucharitha KV. Millets-review on
nutritional profiles and health
benefits. International Journal of Recent
Scientific Research. 2019;10(7):33943-
33948.
18. Sharma N, Niranjan K. Foxtail millet:
Properties, processing, health benefits,
and uses. Food Reviews International.
2018;34(4):329-363.
19. Ratnavathi CV, Komala VV. Sorghum
grain quality. In Sorghum biochemistry.
Academic Press. 2016;1-61.
20. Reddy OSK. Smart Millet and Human
Health. Green Universe Environmental
Services Society; 2017.
21. Awika JM, Rooney LW. Sorghum
phytochemicals and their potential impact
on human health. Phytochemistry. 2004;
65(9):1199-1221.
22. Upadhyaya HD, Vetriventhan M, Dwivedi
SL, Pattanashetti SK, Singh SK. Proso,
barnyard, little, and kodo millets.
In Genetic and genomic resources for
grain cereals improvement. Academic
Press. 2016;321-343.
23. Rani S, Singh R, Sehrawat R, Kaur BP, &
Upadhyay A. Pearl millet processing: A
review. Nutrition & Food Science. 2018;48
(1):30-44.
24. Prathyusha N, Lakshmi VV, Manasa T.
Review on consumer awareness and
health benefits about millets. The
Pharma Innovation Journal. 2021;10(6):
777-785.
25. Arendt E, Dal Bello F. Gluten-Free Cereal
Products and Beverages. Elsevier; 2011.
26. Madhusudhana R, Padmaja PG, Cheruku
D, Rao KR, Tonnesnesapi VA. ICAR-IIMR
Millets Annual Report 2017-18.
27. Renganathan VG, Vanniarajan C,
Karthikeyan A, Ramalingam J. Barnyard
millet for food and nutritional security:
Current status and future research
direction. Frontiers in Genetics. 2020;11:
500.
28. Sood S, Khulbe RK, Kumar A, Agrawal
PK, Upadhyaya HD. Barnyard millet global
core collection evaluation in the
submontane Himalayan region of India
using multivariate analysis. The Crop
Journal. 2015;3(6):517-525.
29. Pradeep SR, Guha M. Effect of processing
methods on the nutraceutical and
antioxidant properties of little millet
(Panicum sumatrense) extracts. Food
chemistry, (2011). 126(4), 1643-1647.
30. Sarita, E. S., & Singh, E. Potential of
millets: Nutrients composition and health
benefits. Journal of Scientific and
Innovative Research. 2016;5(2):46-50.
31. Vishakha DRB. Potential of millets:
Nutrients composition and health benefits.
International Journal of Universal Science
and Engineering. 2016;2. ISSN: 2454-
7581
32. Hassan ZM, Sebola NA, Mabelebele M.
The nutritional use of millet grain for food
and feed: A review. Agriculture & food
security. 2021;10:1-14.
33. Saleh ASM, Zhang Q, Chen J, Shen Q.
Millet grains: Nutritional quality,
processing, and potential health benefits.
Comprehensive Reviews in Food Science
and Food Safety. 2013;12(3):281-295.
34. Chandrasekara A, Shahidi F. Content of
insoluble bound phenolics in millets and
their contribution to antioxidant capacity.
Journal of Agriculture and Food Chemistry.
2010;58(11):6706-6714.
35. Habiyaremye C, Matanguihan JB, D.
Alpoim Guedes J, Ganjyal GM, Whiteman
MR, Kidwell KK, Murphy KM. Proso millet
(Panicum miliaceum L.) and its potential
for cultivation in the Pacific Northwest, US:
Kumar et al.; Int. J. Environ. Clim. Change, vol. 13, no. 9, pp. 2531-2538, 2023; Article no.IJECC.103646
2538
A review. Frontiers in Plant Science.
2017;1961.
36. Muthamilarasan M, Dhaka A, Yadav R,
Prasad M. Exploration of millet models for
developing nutrient rich graminaceous
crops. Plant Science. 2016;242:89-97.
37. Kumar S, Singh S, Yadav R, Kumar M,
Yadav S. Millets: An ancient food and its
nutritional importance for human health.
Agrospheres: e-Newsletter. 2023;4(7):1-4.
ISSN (E): 2582-7022
© 2023 Kumar et al.; This is an Open Access article distributed under the terms of the Creative Commons Attribution License
(http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium,
provided the original work is properly cited.
Peer-review history:
The peer review history for this paper can be accessed here:
https://www.sdiarticle5.com/review-history/103646