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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

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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

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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

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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

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1976

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1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

2002

2004

2006

2008

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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

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(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

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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.

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