Post on 13-Mar-2020
This article was originally published in the Encyclopedia of Food and Health published by Elsevier, and the attached copy is provided by Elsevier for the author's benefit and for the benefit of the author’s institution, for non-commercial research and educational use including without limitation use in instruction at your institution,
sending it to specific colleagues who you know, and providing a copy to your institution’s administrator.
All other uses, reproduction and distribution, including without limitation commercial reprints, selling or licensing copies or access, or posting on open internet sites, your personal or institution’s website or repository, are prohibited. For exceptions, permission may be sought for such use through Elsevier's permissions site at:
http://www.elsevier.com/locate/permissionusematerial Tanumihardjo S.A., Suri D., Simon P. and Goldman I.L. (2016) Vegetables of Temperate Climates: Carrot, Parsnip, and Beetroot. In: Caballero, B., Finglas, P., and Toldrá, F. (eds.) The Encyclopedia of Food and Health vol. 5, pp. 387-392. Oxford: Academic Press.
© 2016 Elsevier Ltd. All rights reserved.
Author's personal copy
Vegetables of Temperate Climates: Carrot, Parsnip, and BeetrootSA Tanumihardjo, D Suri, P Simon, and IL Goldman, University of Wisconsin-Madison, Madison, WI, USA
ã 2016 Elsevier Ltd. All rights reserved.
Sources and Production
Carrots (Daucus carota L.), parsnips (Pastinaca sativa L.), and
beets (Beta vulgaris L.) are horticultural crops that are grown on
a relatively small scale compared with staple food crops, such
as rice, maize, and wheat. Unlike cereal grains and dry legumes,
many horticultural crops have a relatively short shelf life,
requiring ready access to cold storage, which limits their
long-distance distribution, especially in less-developed coun-
tries. Nonetheless, because all of these vegetables are root
crops, their shelf life is long when kept in cold storage, unlike
leafy green vegetables, such as spinach and lettuce, although
the leaves of carrots and beets can also be consumed.
Plants contain vascular systems that allow them to move
water (xylem) and nutrients (phloem) throughout the plant.
Besides orange, carrots are found in other colors. In unusually
pigmented carrots and beets, the xylem and phloem are readily
identifiable (Figure 1). Carrots and beets with more than one
color are sometimes referred to as functional foods or designer
vegetables. Purple color in carrots is usually darker in the outer
phloem of the root and sometimes only on the root surface.
Carrots are available around the world (Table 1) and do
well in cooler climates. The first definite records of carrots
being used as a root crop are in Afghanistan and surrounding
regions of Central Asia around 1100 years ago, when purple
and yellow carrots were described. There are some indications
that carrot may have been a root crop in the Roman Empire,
but records are ambiguous. The color of carrots is an important
part of the history of this crop. Orange carrots were first
recorded in Europe in the 1500s and are the predominant
color of the crop in all growing regions of the world today.
Red carrots are primarily of Asian origin and are still common
today. Purple carrots predate orange carrots and were one of
the first types to be consumed by humans in Central Asia and
the Middle East. Although no longer widely grown, white
carrots, which lack pigment, were developed as a fodder crop
for feeding livestock in Europe.
Biofortification is the process of breeding crops for
enhanced nutritional value. Biofortification of orange carrots
has resulted in carrots with high levels of a- and b-carotene(Figure 2) with an emphasis on breeding for deeper uniform
orange color. Studies have shown that these carrots provide a
little extra vitamin A when fed at similar levels in animals and
humans, but substantial extra amounts of a- and b-carotene,which both have antioxidant activity, are made available to
tissues. Other color combinations have been bred and include
purple-white, purple-yellow, purple-orange, purple-red,
purple-orange-red, red-orange, and orange-yellow.
Parsnip is a vegetable plant in the family Apiaceae. The plant
was domesticated in the Mediterranean and was consumed in
Roman times. Some confusion exists in historical accounts of
this vegetable due to its similarity with carrot, to which it is
related. White carrots exist but are not the same vegetable as
Encyclopedia of Food and Health http://dx.doi.org/10.1016/B978-0-12-384947-2.00
The Encyclopedia of Food and Healt
parsnips. Parsnip is biennial and produces a rosette of leaves
and a swollen taproot during the first season of growth. It is
well adapted to cool growing regions and substantial produc-
tion occurs in Canada.
Table beet was domesticated in the Mediterranean and
originally used as a leaf crop. In its earliest forms, the crop
did not have a swollen root and was only consumed for its
leaves and petioles. Swiss chard most likely resembles this early
form of the crop. As beet moved throughout the Mediterranean
region and spread north, selection occurred for a swollen root
that could be stored throughout the winter. This process of
selection resulted in swollen rooted forms that became the
modern, pigmented table beet. Selection among the swollen
rooted forms also resulted in two additional crops: fodder beet
and sugar beet; the former is used for livestock and the latter as
an industrial source of sucrose. Sugar beet was developed in the
eighteenth century from white fodder beets. A sugar beet is
about 30 cm (12 in.) long and weighs 1–2 kg (2–5 pounds)
at harvest.
Patterns of Consumption
Carrots, parsnips, and beets, like other root vegetables, store
well and can be eaten throughout the winter when many other
vegetables are out of season. They will keep best when stored in
the refrigerator, in the crisper drawer, or in plastic bags and will
last for 1 month or more.
Carrots are a popular vegetable, especially in Europe and
the United States, and fresh-market carrot consumption in the
United States has increased recently due in part to the intro-
duction of ‘cut-and-peel’ carrots. Cut-and-peeled carrots offer a
convenience to consumers in their ready-to-eat form that
comes in a variety of package sizes. In the United States,
�4 kg (9 pounds) are available per capita each year (Figure 3
(a)). Orange carrots are likely the highest source of a- and
b-carotene in the diet of many people in the United States,
and thus, modern orange carrots are a significant source of
vitamin A.
Carrot leaves are consumed in parts of Asia, used either
fresh in a salad or cooked in other dishes. The young tender
leaves are occasionally used as a stir-fried herb in China and
Japan. Carrot leaves have a similar appearance to some of its
wild relatives that are not carrots, and some of these wild
relatives, such as hogweed or cow parsnip, have toxic com-
pounds in their leaves. Carrot top consumers should avoid
leaves from these wild plants. In the leaves, the carotenoids
are located in the photosystems of the inner chloroplast mem-
brane usually associated with lipids. Carrot leaves have a dif-
ferent carotenoid profile than the roots.
Parsnips can be eaten raw but are usually cooked. Taproots
of parsnips have a mild and very pleasant flavor and are prized
as an ingredient in soups and stews because of their rich flavor.
714-5 387h, (2016), vol. 5, pp. 387-392
Table beet with red andyellow cambial rings
Carrot with purple phloem andorange-red/yellow xylem
Phloem
Xylem
Figure 1 The accumulation of pigments in beet and carrot storage roots often varies across root tissues, and as a consequence, nutritional valuevaries. Beetroots have multiple cambia and, with that, concentric rings of xylem and phloem tissue, while carrot roots have one cambium that separatesthe xylem (core) and phloem (cortex).
Table 1 World carrot production and availability, 1965–2011
Continent Variable 1965 1975 1985 1995 2005 2011
Africa Area (% world) 8 5 6 8 8 9Yield (ton ha�1) 11 12 12 12 14 16
Asia Area (% world) 8 27 29 34 53 58Yield (ton ha�1) 28 17 21 22 23 32
Europe Area (% world) 54 53 50 43 28 23Yield (ton ha�1) 24 24 28 20 27 31
Americas Area (% world) 21 14 14 14 10 10Yield (ton ha�1) 22 25 24 29 29 31
Oceania Area (% world) 2 1 1 1 1 1Yield (ton ha�1) 27 32 32 31 42 49
World Area (1000 ha) 196 459 558 756 1151 1174Yield (ton ha�1) 22 19 22 21 24 30Availability (kg per capita) 1.3 2.2 2.5 2.8 4.3 5.1
Average of 3 years (e.g., 1975¼ average of 1974–76).
Source : FAO yearbook production statistics.
388 Vegetables of Temperate Climates: Carrot, Parsnip, and Beetroot
Author's personal copy
They contain more sugar and starch than other vegetable mem-
bers of the Apiaceae family, such as carrot, and appear to have
been used as a source of both of these compounds prior to the
introduction of the potato. Parsnips are sweeter than typical
carrots, especially when cooked. Parsnips have sugar content
comparable to fruits, such as bananas and grapes. They can be
baked, boiled, pureed, and roasted and are sometimes fried to
make chips. It is interesting to note that the starch in parsnips
converts to sugar when exposed to cold and thus winter pars-
nips are sweeter than autumn parsnips. Refrigeration will also
cause them to develop more sweetness.
The table beet is consumed in a variety of ways. Compared
with carrots, however, availability per capita in the United
States has tended to decrease over the past few decades
(Figure 3(b)). Leaves, particularly small leaves known as
‘baby leaves,’ are consumed as a salad crop. Roots are eaten
in salads, placed on sandwiches, pickled, roasted, boiled, or
used in soup. A substantial portion of the United States crop is
canned. Beet root can be eaten raw and will maintain more of
its folate content if not cooked. When table beet roots are
consumed, the hypocotyl tissue is also consumed as it is a
transitional zone between the root and stem. The root/hypo-
cotyl is actually composed of supernumerary cambia, or zones
The Encyclopedia of Food and Health
of xylem and phloem tissue, that increase in size during
growth. The root/hypocotyl region also contains storage paren-
chyma cells, where sucrose is stored. Table beet has long been
known as a sweetener and was likely used in Roman times for
this purpose.
The sugar beet was developed following the Napoleonic
wars when Europe needed a domestic source of sugar that did
not depend on the West Indies sugar trade. Sugar beet is a
natural source of sucrose, which is not different from cane
sugar. Sugar beets contain about 18% sucrose, which is about
two to three times higher than table beets. Sugar beet must be
processed quickly because it is perishable. Beet sugar represents
about 50% of domestically produced sugar in the United
States.
Availability, Absorption, and Metabolism
In general, phytochemicals found in vegetables have putative
mechanisms of action in the body including antioxidant
effects, modulation of detoxifying enzymes, stimulation of
the immune system, modulation of hormone metabolism,
and antibacterial and antiviral effects. Brightly colored
, (2016), vol. 5, pp. 387-392
OH
HO
β-carotene
lutein
lycopene
α-carotene
Figure 2 The four main carotenoids that are found in carrots. a- and b-carotene predominate in orange carrots. Lutein is relatively high in yellowcarrots compared with b-carotene. Lycopene is high in red carrots in addition to high levels of b-carotene.
Vegetables of Temperate Climates: Carrot, Parsnip, and Beetroot 389
Author's personal copy
vegetables, such as carrots and beets, generally contain high
amounts of phytochemicals and nutrients.
In addition to being a significant source of b-carotene,orange carrots are likely the highest source of a-caroteneamong all vegetables. Both of these orange compounds from
carrots provide vitamin A upon central cleavage. Most mam-
mals, including humans, are able to cleave a- and b-carotene tovitamin A. a-Carotene provides one molecule of vitamin A and
one molecule of a compound commonly called a-retinol,while b-carotene can provide two molecules of vitamin A due
to its symmetrical structure (Figure 2). Thus, orange, red, and
some purple carrots are great sources of vitamin A. Vitamin A is
essential for healthy eyes, cell growth, and reproduction. It is
also important in strengthening the immune system by keep-
ing the skin, lungs, and intestinal tract mucosa healthy. When
carrots are eaten, not only do they provide vitamin A, but also
the excess carotenoids can be absorbed and circulated intact in
the human body. In circulation, a-carotene and b-carotene arepredominantly associated with low-density lipoproteins.
Therefore, some animals that have higher-density lipoproteins,
such as gerbils and chickens, may not circulate much b-carotene in the blood.
Carrots of other colors have a different carotenoid profile.
Yellow carrots contain lutein, which is bioavailable to humans,
in addition to small amounts of b-carotene. Lutein is a xan-
thophyll carotenoid, which means it is partially oxygenated.
Because it contains hydroxyl groups on both sides of the mol-
ecule (Figure 2), lutein cannot be cleaved by mammals to form
molecules of vitamin A. A human study demonstrated that
lutein from yellow carrots was 65% as bioavailable as that
from a lutein supplement dissolved in oil.
Red carrots accumulate lycopene, a common pigment in
red tomatoes, in addition to high amounts of b-carotene. Like
The Encyclopedia of Food and Healt
a- and b-carotene, lycopene is a hydrocarbon carotenoid, but it
does not have any cyclic rings, making it quite different struc-
turally from the other well-known carotenoids in carrots
(Figure 2). Lycopene from red carrots is about 40% as bio-
available as that from tomato paste. For consumers who do not
like tomatoes, red carrots are another food source of lycopene.
Consumers in India actually prefer red-pigmented carrots to
orange ones.
Other phytochemicals present in purple carrots include
flavonoids, such as red or blue anthocyanins (Figure 4), and
purple carrots may, or may not, contain carotenoids. Anthocy-
anin pigmentation develops independently of carotenoid
colors, so some purple carrots contain a- and b-carotene. Pur-ple color may mask the appearance of carotenoids. The purple
anthocyanins found in carrots are sometimes used as food
colorants. Some of the carrot anthocyanins have an acyl chem-
ical group, while some do not. The acylated anthocyanins of
carrot are more stable when used as a food colorant, but the
nonacylated anthocyanins are more bioavailable. Some strains
of purple carrot are sometimes referred to as ‘black’ carrot
because the anthocyanins are so concentrated that they have
deep purple color in the phloem and xylem. Efforts to breed
carrots of several colors have been on the rise, and within the
past decade, purple-orange-red carrots have been bred for
increased red color. These particular carrots would have antho-
cyanins, a- and b-carotene, in addition to lycopene (Figure 1).
A common name for these types of carrots is ‘rainbow carrots.’
Through outreach efforts, rainbow carrot seeds have been dis-
tributed to community and youth gardeners to build awareness
and to use the harvested carrots to demonstrate the diversity of
pigments in vegetables.
Lastly, carrots also contain phenolic acids that have a single
aromatic ring. The main phenolic acids are chlorogenic acids
h, (2016), vol. 5, pp. 387-392
(a)
(b)
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
1970
1972
1974
1976
1978
1980
1982
1984
1986
1988
1990
1992
1994
1996
1998
2000
2002
2004
2006
2008
2010
2012
Carrot availability by year, kilograms per capita
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1970
1972
1974
1976
1978
1980
1982
1984
1986
1988
1990
1992
1994
1996
1998
2000
2002
2004
2006
2008
2010
2012
Beet availability by year, kilograms per capita
Figure 3 Carrot and beet availability in the United States over the past few decades expressed in kilograms.
390 Vegetables of Temperate Climates: Carrot, Parsnip, and Beetroot
Author's personal copy
(Figure 4), which are hydroxycinnamic acid derivatives formed
by the esterification of cinnamic acids with quinic acid. These
compounds contribute to the organoleptic properties of fresh
and processed carrots. Approximately 30% of chlorogenic
acids are absorbed by the intestine and the remainder is exten-
sively metabolized by colonic microflora.
Although typical parsnips are white, they contain com-
pounds known as polyacetylenes, which may impart beneficial
properties to this vegetable. Plants synthesize polyacetylenes to
protect them against pathogens and pests. They are derived
from unsaturated fatty acids. One type of polyacetylene called
falcarinol is highly bioavailable in humans, being rapidly
absorbed after ingestion (Figure 4). Interestingly, falcarinol
was viewed as a potentially undesirable component of food
in the 1980s, and now, it is viewed by some as desirable.
Table beet is colored by betalain pigments (Figure 5). The
betalains are a unique class of alkaloid pigments found in plant
species in the order Caryophyllales and in some fungi. Tyrosine
is converted to L-DOPA via hydroxylation and subsequently to
betalamic acids via the extradiol ring cleavage reaction. Beta-
lains are ultimately formed via spontaneous chemical conver-
sion. Recently, the R locus that controls betalain pigment
production in table beet was identified as a novel cytochrome
The Encyclopedia of Food and Health
P450. This protein provides the cyclo-DOPA moiety that is
required for all red betacyanin pigments. Selection has been
effective at increasing betalain concentration in table beet.
Betalains are water-soluble, fairly easy to extract, and a com-
monly used source of natural colorants. After ingestion, beta-
lains are thought to be degraded in the stomach and absorbed
in the gut, possibly through passive diffusion. An estimated
50% of betalain is lost during digestion, and urinary betalain
ranges between 0.3% and 1% after consumption of beet juice
or extract, which may reflect low absorption. Food processing
also affects betalain absorption, with lower bioavailability
from the whole beet matrix compared with purified beet juice
or extract.
Health Effects
Root vegetables provide energy through their carbohydrate
content and are naturally low in fat. Root vegetables are a
good source of fiber, ranging from 3 g fiber in 100 g of raw
carrots and beets to 5 g in 100 g of parsnips. Cooking tends to
lower the fiber content in beets and parsnips. Carrot fiber is
highly regarded and has become of interest to food processers
, (2016), vol. 5, pp. 387-392
OH
OHO
OH
OR
OH
+
cyanidin
Where R:2"-xylose-6"-galactoside2"-xylose-6"-glucose-galactoside2"-xylose-6"-sinapoyl-glucose-galactoside2"-xylose-6"-feruloyl-glucose-galactoside2"-xylose-6"-(4-coumaroyl)glucose-galactoside
O
OH
HO
HO COOH
O
OH
OH
chlorogenic acid
HO
falcarinol
Figure 4 Carrots contain many phytochemicals. Falcarinol contributesto carrot sensory characteristics and is also found in parsnips.Chlorogenic acid is a common phenolic acid found in carrots.Anthocyanins are the red and blue compounds that give purple carrotstheir hue and contribute to their high antioxidant capacity.
Betalacyanin red Betaxanthin yellow
HO
HO
N+
COOH
H
NHOOC COOH
H
NHOOC COOH
H
N+H
R HCOOH
Figure 5 Betalains are the primary pigments in red and yellow beets.These water-soluble pigments are unique to the order Caryophyllales, ofwhich the Amaranthaceae family, and the table beet in particular, is amember. The betalains are used as a natural alternative to synthetic fooddyes in certain food products. They show considerable antioxidant activityand may have potential in improving the health functionality of foods.
Vegetables of Temperate Climates: Carrot, Parsnip, and Beetroot 391
The Encyclopedia of Food and Healt
Author's personal copy
due to the large quantities of carrot waste, known as pomace,
created in the cut-and-peel and juice industries. The insoluble
fibers, primarily cellulose and hemicellulose, constitute the
greatest portion of the total dietary fiber with small amounts
of lignin. The soluble fibers include fermentable hemicellulose
and pectin. The fiber composition of dried carrot pomace
differs from whole carrot and depends on the processing
method.
Raw root vegetables are also a good source of water ranging
from 80% in parsnips to 88% in carrots and beets. Boiling the
vegetables does not appreciably change the water content
(<2%) when based on a 100 g serving. While cooking breaks
down some nutrients, both carotenoids and anthocyanins of
carrot are quite stable with light cooking. Root vegetables are
also a good source of potassium providing �350 mg in 100 g.
Research has focused on the numerous health benefits of
phytochemicals, including those that are found in the root
vegetables. Carrots, in particular, have been studied for nutri-
tive benefits and color components and are widely considered
a ‘functional food.’ The pigments in carrots serve an important
role because they have been associated with reduced risks of
atherosclerosis, cancer, and inflammation. Carrots have anti-
oxidant capacity because both a-carotene and b-carotene are
antioxidants, which are important to trap free radicals and
fight against heart disease. Both carotenoids have been
reported to have anticancer potential. Yellow carrots contain
lutein, which has been implicated in improved eye health.
Specifically, lutein and zeaxanthin are concentrated in the
macula of the eye and may be important in preventing macular
degeneration. Lutein has also been implemented in preventing
some forms of cancers and reducing the risk of atherosclerosis.
Intake of dietary lycopene, as found in red and some purple
carrots, has been associated with a reduced incidence of some
forms of cancer. Lycopene, which has much higher antioxidant
potential than b-carotene, is also associated with a reduced risk
of serum lipid oxidation and heart disease.
When carrots or carrot juice are consumed at a high level in
the diet, a condition known as hypercarotenemia can occur.
This is due in part to the downregulation of bioconversion of
the provitamin A carotenoids to vitamin A as a way to protect
the human body from hypervitaminosis A due to high vegeta-
ble intake. The carotenoids will accumulate in the adipose
tissue and the yellow pigmentation of the palms is usually
first noticeable. This is thought to be a benign condition.
Eleven different phenolic acids in orange, purple, yellow,
and white carrots have been identified. Total concentration of
all identified phenolic acids is greatest in the purple carrots
followed by orange, white, and yellow. In particular, chloro-
genic acid consumption has been associated with reductions in
several chronic diseases.
Anthocyanins in purple and black carrots act as powerful
antioxidants to sequester harmful free radicals in the body;
however, human data are lacking. Anthocyanins may prevent
heart disease by acting as anti-inflammatory agents and reduc-
ing lipid oxidation. Solid-colored purple carrots contain the
most phenolic compounds and therefore may have higher
antioxidant capacity in the human body.
Parsnips are a better source of vitamin C than carrots and
beets. Parsnips and beets provide more folate than carrots.
Falcarinol may be involved in carrot and parsnip beneficial
h, (2016), vol. 5, pp. 387-392
392 Vegetables of Temperate Climates: Carrot, Parsnip, and Beetroot
Author's personal copy
health effects including anti-inflammatory, antiplatelet
aggregation, and potential anticancer activity. While falcarinol
can cause allergic skin reactions, contact dermatitis from
Apiaceae family vegetables is rare, likely due to the relatively
low concentrations of falcarinol in the species commonly
consumed or sensitization from oral intake.
Parsnip leaves also contain furanocoumarins, which can
cause photodermatitis if they are touched or brush up against
the skin in the presence of light. Burns caused by these com-
pounds can be serious and can leave scars that do not easily
disappear. Parsnips are therefore difficult to handle and indi-
viduals handling the crop require substantial protection during
production. Parsnip root contains photocarcinogenic psora-
lens, which are not destroyed by cooking. However, the effect
and potential toxicity of these chemicals from normal human
consumption are not known.
Beet greens by weight have even more micronutrients than
beetroot, including vitamin A as b-carotene, vitamin C, vita-
min K, calcium, iron, magnesium, potassium, copper, and
manganese. Beet leaves also contain a substantial amount of
lutein and zeaxanthin and thus have health benefits associated
with those carotenoids as detailed earlier for carrots.
Beets are among the vegetables with the highest antioxidant
content. Betalain pigments are among the antioxidants in beets
and may be associated with cancer prevention. Betalains in
beet extract reduced tumors associated with skin and lung
cancer in mice, but no human studies have been done to date
that demonstrate substantial health benefits. Betalains have a
large nonpolar surface area that allows them to interact with
lipid membranes and low-density lipoprotein particles in the
blood reducing oxidation.
Oxalic acid is related to the formation of kidney stones and
has other antinutritive properties. Table beet is considered a
high oxalate food, and therefore, breeding to decrease oxalic
acid levels is an area of interest. In a collection of table beet
cultivars, mean values were from 722 to 1909 mg in 100 g of
leaf tissue and 553 to 1679 mg in 100 g leaf tissue for total and
soluble oxalate levels, respectively. Root-soluble oxalate values
ranged from 103 to 171 mg in 100 g of root tissue, and total
values ranged from 95 to 142 mg in 100 g of root tissue. These
findings confirm relatively high levels of oxalate in table beet.
Many people are familiar with ‘beeturia,’ or the excretion of
red urine following beet consumption. This occurs in 10–14%
of the population and seems to be a harmless idiosyncratic
reaction relating to digestion of the beet pigments. The occur-
rence of beeturia is probably related more to an individual’s
physiological conditions (such as stomach acidity), nutritional
status, type of beet, and amount consumed, rather than genet-
ics as previously thought.
Summary
Root vegetables are a source of energy in the form of carbohy-
drates and a good fiber source. They contain essential nutrients
The Encyclopedia of Food and Health
as well as a variety of classes of phytochemicals associated with
optimal health.
See also: Antioxidants: Role on Health and Prevention; Bioavailabilityof Nutrients; Carotenoids: Occurrence, Properties and Determination;Colors: Properties and Determination of Natural Pigments; DietaryFiber: Determination; Functional Foods; Phenolic Compounds:Bioavailability and Health Effects; Phenolic Compounds: Occurrence,Classes, and Analysis; Salad Crops: Root, Bulb, and Tuber Crops;Sugar Alcohols; Tannins.
Further Reading
Arscott SA and Tanumihardjo SA (2010) Carrots of many colors provide basic nutritionand bioavailable phytochemicals acting as a functional food. ComprehensiveReviews in Food Science and Food Safety 9: 223–239.
Christensen LP and Brandt K (2006) Bioactive polyacetylenes in food plants of theApiaceae family: occurrence, bioactivity and analysis. Journal of Pharmaceutical andBiomedical Analysis 41: 683–693.
Christiansen LP (2011) Aliphatic C17-polyacetylenes of the falcarinol type as potentialhealth promoting compounds in food plants of the Apiaceae family. Recent Patentson Food, Nutrition & Agriculture 3: 64–77.
Freidig A and Goldman IL (2011) Variation in oxalic acid content among commercialtable beet cultivars and related crops. Journal of the American Society forHorticultural Science 136: 54–60.
Gaertner VL and Goldman IL (2005) Pigment distribution and total dissolved solids ofselected cycles of table beet from a recurrent selection program for increasedpigment. Journal of the American Society for Horticultural Science 130: 424–433.
Hatlestad GJ, Sunnadeniya RM, Akhavan NA, Gonzalez A, Goldman IL, McGrath JM,and Lloyd AM (2012) The beet R locus encodes a new cytochrome P450 requiredfor red betalain production. Nature Genetics 44: 816–820.
Kanner J, Harel S, and Granit R (2001) Betalains. A new class of dietary antioxidants.Journal of Agricultural and Food Chemistry 49: 5178–5185.
Kapadia GJ, Tokuda H, Konoshima T, and Nishino H (1996) Chemoprevention of lungand skin cancer by Beta vulgaris (beet) root extract. Cancer Letters 100: 211–214.
Ou B, Huang D, Hampsch-Woodill M, Flanagan JA, and Deemer EK (2002) Analysis ofantioxidant activities of common vegetables employing oxygen radical absorbancecapacity (ORAC) and ferric reducing antioxidant power (FRAP) assays: acomparative study. Journal of Agricultural and Food Chemistry 50: 3122–3128.
Schmaelzle S and Tanumihardjo SA (2013) Chapter 2: Carrots of various colors.In: Tanumihardjo SA (ed.) Carotenoids and human health, pp. 21–28. New York:Springer Science and Business Media.
Simon PW, Tanumihardjo SA, Clevidence BA, and Novotny JA (2008) Role of color andpigments in breeding, genetics, and nutritional improvement of carrots.In: Culver CA and Worlstad RE (eds.) Color quality of fresh and processed foods.ACS symposium series 983pp. 151–165. Washington, DC: ACS Books.
Simon P, Bowman M, and Tanumihardjo SA (2013) Chapter 18: Horticultural crops as asource of carotenoids. In: Tanumihardjo SA (ed.) Carotenoids and human health,pp. 293–301. New York: Springer Science and Business Media.
Stintzing FC and Carle R (2004) Functional properties of anthocyanins and betalains inplants, food, and in human nutrition. Trends in Food Science & Technology15: 19–38.
Tesoriere L, Allegra M, Butera D, and Livrea MA (2004) Absorption, excretion, anddistribution of dietary antioxidant betalains in LDLs: potential health effects ofbetalains in humans. American Journal of Clinical Nutrition 80: 941–945.
Tesoriere L, Fazzari M, Angileri F, Gentile C, and Livrea MA (2008) In vitro digestion ofbetalainic foods. Stability and bioaccessibility of betaxanthins and betacyanins andantioxidative potential of food digesta. Journal of Agricultural and Food Chemistry56: 10487–10492.
Lucier, G. and Lin, B. H. (eds) (2007). Factors affecting carrot consumption in theUnited States. USDA Economic Research Service. http://www.ers.usda.gov/media/198875/vgs31901_1_.pdf.
, (2016), vol. 5, pp. 387-392