Carrot, Parsnip, and Beetroot

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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.

Vegetables of Temperate Climates: Carrot, Parsnip, and Beetroot

SA Tanumihardjo, D Suri, P Simon, and IL Goldman, University of Wisconsin-Madison, Madison, WI, USA

Sources and Production parsnips. Parsnip is biennial and produces a rosette of leaves and a swollen taproot during the first season of growth. It is Carrots (Daucus carota L.), parsnips (Pastinaca sativa L.), and well adapted to cool growing regions and substantial produc- beets (Beta vulgaris L.) are horticultural crops that are grown on tion occurs in Canada. a relatively small scale compared with staple food crops, such Table beet was domesticated in the Mediterranean and as rice, maize, and wheat. Unlike cereal grains and dry legumes, originally used as a leaf crop. In its earliest forms, the crop many horticultural crops have a relatively short shelf life, did not have a swollen root and was only consumed for its requiring ready access to cold storage, which limits their leaves and petioles. Swiss chard most likely resembles this early long-distance distribution, especially in less-developed coun- form of the crop. As beet moved throughout the Mediterranean tries. Nonetheless, because all of these vegetables are root region and spread north, selection occurred for a swollen root crops, their shelf life is long when kept in cold storage, unlike that could be stored throughout the winter. This process of leafy green vegetables, such as spinach and lettuce, although selection resulted in swollen rooted forms that became the the leaves of carrots and beets can also be consumed. modern, pigmented table beet. Selection among the swollen Plants contain vascular systems that allow them to move rooted forms also resulted in two additional crops: fodder beet water (xylem) and nutrients (phloem) throughout the plant. and sugar beet; the former is used for livestock and the latter as

Besides orange, carrots are found in other colors. In unusually an industrial source of sucrose. Sugar beet was developed in the pigmented carrots and beets, the xylem and phloem are readily eighteenth century from white fodder beets. A sugar beet is identifiable (Figure 1). Carrots and beets with more than one about 30 cm (12 in.) long and weighs 1–2 kg (2–5 pounds) color are sometimes referred to as functional foods or designer at harvest. 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 Patterns of Consumption well in cooler climates. The first definite records of carrots being used as a root crop are in Afghanistan and surrounding Carrots, parsnips, and beets, like other root vegetables, store regions of Central Asia around 1100 years ago, when purple well and can be eaten throughout the winter when many other and yellow carrots were described. There are some indications vegetables are out of season. They will keep best when stored in that carrot may have been a root crop in the Roman Empire, the refrigerator, in the crisper drawer, or in plastic bags and will but records are ambiguous. The color of carrots is an important last for 1 month or more. part of the history of this crop. Orange carrots were first Carrots are a popular vegetable, especially in Europe and recorded in Europe in the 1500s and are the predominant the United States, and fresh-market carrot consumption in the color of the crop in all growing regions of the world today. United States has increased recently due in part to the intro- Red carrots are primarily of Asian origin and are still common duction of ‘cut-and-peel’ carrots. Cut-and-peeled carrots offer a today. Purple carrots predate orange carrots and were one of convenience to consumers in their ready-to-eat form that the first types to be consumed by humans in Central Asia and comes in a variety of package sizes. In the United States, the Middle East. Although no longer widely grown, white 4 kg (9 pounds) are available per capita each year (Figure 3 carrots, which lack pigment, were developed as a fodder crop a (a)). Orange carrots are likely the highest source of - and for feeding livestock in Europe. b-carotene in the diet of many people in the United States, Biofortification is the process of breeding crops for and thus, modern orange carrots are a significant source of enhanced nutritional value. Biofortification of orange carrots vitamin A. has resulted in carrots with high levels of a- and b-carotene Carrot leaves are consumed in parts of Asia, used either

(Figure 2) with an emphasis on breeding for deeper uniform fresh in a salad or cooked in other dishes. The young tender orange color. Studies have shown that these carrots provide a leaves are occasionally used as a stir-fried herb in China and little extra vitamin A when fed at similar levels in animals and Japan. Carrot leaves have a similar appearance to some of its humans, but substantial extra amounts of a- and b-carotene, wild relatives that are not carrots, and some of these wild which both have antioxidant activity, are made available to relatives, such as hogweed or cow parsnip, have toxic com- tissues. Other color combinations have been bred and include pounds in their leaves. Carrot top consumers should avoid purple-white, purple-yellow, purple-orange, purple-red, leaves from these wild plants. In the leaves, the carotenoids purple-orange-red, red-orange, and orange-yellow. are located in the photosystems of the inner chloroplast mem- Parsnip is a vegetable plant in the family Apiaceae. The plant brane usually associated with lipids. Carrot leaves have a dif- was domesticated in the Mediterranean and was consumed in ferent carotenoid profile than the roots. Roman times. Some confusion exists in historical accounts of Parsnips can be eaten raw but are usually cooked. Taproots this vegetable due to its similarity with carrot, to which it is of parsnips have a mild and very pleasant flavor and are prized related. White carrots exist but are not the same vegetable as as an ingredient in soups and stews because of their rich flavor.

Encyclopedia of Food and Health http://dx.doi.org/10.1016/B978-0-12-384947-2.00714-5 387 The Encyclopedia of Food and Health, (2016), vol. 5, pp. 387-392

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388 Vegetables of Temperate Climates: Carrot, Parsnip, and Beetroot

Xylem

Phloem

Table beet with red and Carrot with purple phloem and yellow cambial rings orange-red/yellow xylem

Figure 1 The accumulation of pigments in beet and carrot storage roots often varies across root tissues, and as a consequence, nutritional value varies. Beetroots have multiple cambia and, with that, concentric rings of xylem and phloem tissue, while carrot roots have one cambium that separates the 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 9 1 Yield (ton ha ) 111212121416 Asia Area (% world) 8 27 29 34 53 58 1 Yield (ton ha ) 281721222332 Europe Area (% world) 54 53 50 43 28 23 Yield (ton ha 1) 242428202731 Americas Area (% world) 21 14 14 14 10 10 Yield (ton ha1) 222524292931 Oceania Area (% world) 2 1 1 1 1 1 Yield (ton ha1) 273232314249 World Area (1000 ha) 196 459 558 756 1151 1174 Yield (ton ha1) 221922212430

Availability (kg per capita) 1.3 2.2 2.5 2.8 4.3 5.1

Average of 3 years (e.g., 1975¼average of 1974–76).

Source: FAO yearbook production statistics.

They contain more sugar and starch than other vegetable mem- of xylem and phloem tissue, that increase in size during bers of the Apiaceae family, such as carrot, and appear to have growth. The root/hypocotyl region also contains storage paren- been used as a source of both of these compounds prior to the chyma cells, where sucrose is stored. Table beet has long been introduction of the potato. Parsnips are sweeter than typical known as a sweetener and was likely used in Roman times for carrots, especially when cooked. Parsnips have sugar content this purpose. comparable to fruits, such as bananas and grapes. They can be The sugar beet was developed following the Napoleonic baked, boiled, pureed, and roasted and are sometimes fried to wars when Europe needed a domestic source of sugar that did make chips. It is interesting to note that the starch in parsnips not depend on the West Indies sugar trade. Sugar beet is a converts to sugar when exposed to cold and thus winter pars- natural source of sucrose, which is not different from cane nips are sweeter than autumn parsnips. Refrigeration will also sugar. Sugar beets contain about 18% sucrose, which is about cause them to develop more sweetness. two to three times higher than table beets. Sugar beet must be The table beet is consumed in a variety of ways. Compared processed quickly because it is perishable. Beet sugar represents with carrots, however, availability per capita in the United about 50% of domestically produced sugar in the United States has tended to decrease over the past few decades States. (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 Availability, Absorption, and Metabolism used in soup. A substantial portion of the United States crop is canned. Beet root can be eaten raw and will maintain more of In general, phytochemicals found in vegetables have putative its folate content if not cooked. When table beet roots are mechanisms of action in the body including antioxidant consumed, the hypocotyl tissue is also consumed as it is a effects, modulation of detoxifying enzymes, stimulation of transitional zone between the root and stem. The root/hypo- the immune system, modulation of hormone metabolism, cotyl is actually composed of supernumerary cambia, or zones and antibacterial and antiviral effects. Brightly colored

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Vegetables of Temperate Climates: Carrot, Parsnip, and Beetroot 389

α-carotene

β-carotene

HO lutein

lycopene

Figure 2 The four main carotenoids that are found in carrots. a- and b-carotene predominate in orange carrots. Lutein is relatively high in yellow carrots compared with b-carotene. Lycopene is high in red carrots in addition to high levels of b-carotene.

vegetables, such as carrots and beets, generally contain high a- and b-carotene, lycopene is a hydrocarbon carotenoid, but it amounts of phytochemicals and nutrients. does not have any cyclic rings, making it quite different struc- In addition to being a significant source of b-carotene, turally from the other well-known carotenoids in carrots orange carrots are likely the highest source of a-carotene (Figure 2). Lycopene from red carrots is about 40% as bio- among all vegetables. Both of these orange compounds from available as that from tomato paste. For consumers who do not carrots provide vitamin A upon central cleavage. Most mam- like tomatoes, red carrots are another food source of lycopene. a b mals, including humans, are able to cleave - and -carotene to Consumers in India actually prefer red-pigmented carrots to a vitamin A. -Carotene provides one molecule of vitamin A and orange ones. one molecule of a compound commonly called a-retinol, Other phytochemicals present in purple carrots include while b-carotene can provide two molecules of vitamin A due flavonoids, such as red or blue anthocyanins (Figure 4), and to its symmetrical structure (Figure 2). Thus, orange, red, and purple carrots may, or may not, contain carotenoids. Anthocy- some purple carrots are great sources of vitamin A. Vitamin A is anin pigmentation develops independently of carotenoid

a b essential for healthy eyes, cell growth, and reproduction. It is colors, so some purple carrots contain - and -carotene. Pur- also important in strengthening the immune system by keep- ple color may mask the appearance of carotenoids. The purple ing the skin, lungs, and intestinal tract mucosa healthy. When anthocyanins found in carrots are sometimes used as food carrots are eaten, not only do they provide vitamin A, but also colorants. Some of the carrot anthocyanins have an acyl chem- the excess carotenoids can be absorbed and circulated intact in ical group, while some do not. The acylated anthocyanins of a b the human body. In circulation, -carotene and -carotene are carrot are more stable when used as a food colorant, but the predominantly associated with low-density lipoproteins. nonacylated anthocyanins are more bioavailable. Some strains Therefore, some animals that have higher-density lipoproteins, of purple carrot are sometimes referred to as ‘black’ carrot such as gerbils and chickens, may not circulate much b- because the anthocyanins are so concentrated that they have carotene in the blood. deep purple color in the phloem and xylem. Efforts to breed

Carrots of other colors have a different carotenoid profile. carrots of several colors have been on the rise, and within the Yellow carrots contain lutein, which is bioavailable to humans, past decade, purple-orange-red carrots have been bred for in addition to small amounts of b-carotene. Lutein is a xan- increased red color. These particular carrots would have antho- thophyll carotenoid, which means it is partially oxygenated. cyanins, a- and b-carotene, in addition to lycopene (Figure 1). Because it contains hydroxyl groups on both sides of the mol- A common name for these types of carrots is ‘rainbow carrots.’ ecule (Figure 2), lutein cannot be cleaved by mammals to form Through outreach efforts, rainbow carrot seeds have been dis- molecules of vitamin A. A human study demonstrated that tributed to community and youth gardeners to build awareness lutein from yellow carrots was 65% as bioavailable as that and to use the harvested carrots to demonstrate the diversity of from a lutein supplement dissolved in oil. pigments in vegetables. Red carrots accumulate lycopene, a common pigment in Lastly, carrots also contain phenolic acids that have a single red tomatoes, in addition to high amounts of b-carotene. Like aromatic ring. The main phenolic acids are chlorogenic acids

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390 Vegetables of Temperate Climates: Carrot, Parsnip, and Beetroot

Carrot availability by year, kilograms per capita 9.0

8.0

7.0 6.0

5.0 4.0

3.0

2.0

1.0

0.0

1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 (a)

Beet availability by year, kilograms per capita 1.0 0.9

0.8 0.7

0.6 0.5

0.4

0.3 0.2

0.1 0.0

1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012

(b) Figure 3 Carrot and beet availability in the United States over the past few decades expressed in kilograms.

(Figure 4), which are hydroxycinnamic acid derivatives formed P450. This protein provides the cyclo-DOPA moiety that is by the esterification of cinnamic acids with quinic acid. These required for all red betacyanin pigments. Selection has been compounds contribute to the organoleptic properties of fresh effective at increasing betalain concentration in table beet. and processed carrots. Approximately 30% of chlorogenic Betalains are water-soluble, fairly easy to extract, and a com- acids are absorbed by the intestine and the remainder is exten- monly used source of natural colorants. After ingestion, beta- sively metabolized by colonic microflora. lains are thought to be degraded in the stomach and absorbed

Although typical parsnips are white, they contain com- in the gut, possibly through passive diffusion. An estimated pounds known as polyacetylenes, which may impart beneficial 50% of betalain is lost during digestion, and urinary betalain properties to this vegetable. Plants synthesize polyacetylenes to ranges between 0.3% and 1% after consumption of beet juice protect them against pathogens and pests. They are derived or extract, which may reflect low absorption. Food processing from unsaturated fatty acids. One type of polyacetylene called also affects betalain absorption, with lower bioavailability falcarinol is highly bioavailable in humans, being rapidly from the whole beet matrix compared with purified beet juice absorbed after ingestion (Figure 4). Interestingly, falcarinol or extract. 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 Health Effects betalains are a unique class of alkaloid pigments found in plant species in the order Caryophyllales and in some fungi. Tyrosine Root vegetables provide energy through their carbohydrate is converted to L-DOPA via hydroxylation and subsequently to content and are naturally low in fat. Root vegetables are a betalamic acids via the extradiol ring cleavage reaction. Beta- good source of fiber, ranging from 3 g fiber in 100 g of raw lains are ultimately formed via spontaneous chemical conver- carrots and beets to 5 g in 100 g of parsnips. Cooking tends to sion. Recently, the R locus that controls betalain pigment lower the fiber content in beets and parsnips. Carrot fiber is production in table beet was identified as a novel cytochrome highly regarded and has become of interest to food processers

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Vegetables of Temperate Climates: Carrot, Parsnip, and Beetroot 391

due to the large quantities of carrot waste, known as pomace, created in the cut-and-peel and juice industries. The insoluble HO fibers, primarily cellulose and hemicellulose, constitute the falcarinol 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

HO COOH differs from whole carrot and depends on the processing

O method. Raw root vegetables are also a good source of water ranging from 80% in parsnips to 88% in carrots and beets. Boiling the HO O vegetables does not appreciably change the water content < OH ( 2%) when based on a 100 g serving. While cooking breaks OH down some nutrients, both carotenoids and anthocyanins of OH carrot are quite stable with light cooking. Root vegetables are chlorogenic acid also a good source of potassium providing 350 mg in 100 g. Research has focused on the numerous health benefits of OH phytochemicals, including those that are found in the root

vegetables. Carrots, in particular, have been studied for nutri- OH tive benefits and color components and are widely considered + a ‘functional food.’ The pigments in carrots serve an important HO O role because they have been associated with reduced risks of atherosclerosis, cancer, and inflammation. Carrots have antioxidant capacity because both a-carotene and b-carotene are OR antioxidants, which are important to trap free radicals and OH fight against heart disease. Both carotenoids have been reported to have anticancer potential. Yellow carrots contain cyanidin lutein, which has been implicated in improved eye health. Specifically, lutein and zeaxanthin are concentrated in the Where R: 2"-xylose-6"-galactoside macula of the eye and may be important in preventing macular 2"-xylose-6"-glucose-galactoside degeneration. Lutein has also been implemented in preventing 2"-xylose-6"-sinapoyl-glucose-galactoside some forms of cancers and reducing the risk of atherosclerosis. 2"-xylose-6"-feruloyl-glucose-galactoside Intake of dietary lycopene, as found in red and some purple 2"-xylose-6"-(4-coumaroyl)glucose-galactoside carrots, has been associated with a reduced incidence of some

Figure 4 Carrots contain many phytochemicals. Falcarinol contributes forms of cancer. Lycopene, which has much higher antioxidant to carrot sensory characteristics and is also found in parsnips. b potential than -carotene, is also associated with a reduced risk Chlorogenic acid is a common phenolic acid found in carrots. of serum lipid oxidation and heart disease. Anthocyanins are the red and blue compounds that give purple carrots When carrots or carrot juice are consumed at a high level in their hue and contribute to their high antioxidant capacity. 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 vegetable intake. The carotenoids will accumulate in the adipose tissue and the yellow pigmentation of the palms is usually HO COOH R H first noticeable. This is thought to be a benign condition. H COOH H + Eleven different phenolic acids in orange, purple, yellow, N+ N HO 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, chlorogenic acid consumption has been associated with reductions in

several chronic diseases. N HOOC COOH HOOC N COOH Anthocyanins in purple and black carrots act as powerful antioxidants to sequester harmful free radicals in the body; H H however, human data are lacking. Anthocyanins may prevent Betalacyanin red Betaxanthin yellow heart disease by acting as anti-inflammatory agents and reduc-

ing lipid oxidation. Solid-colored purple carrots contain the Figure 5 Betalains are the primary pigments in red and yellow beets. These water-soluble pigments are unique to the order Caryophyllales,of most phenolic compounds and therefore may have higher which the Amaranthaceae family, and the table beet in particular, is a antioxidant capacity in the human body. member. The betalains are used as a natural alternative to synthetic food Parsnips are a better source of vitamin C than carrots and dyes in certain food products. They show considerable antioxidant activity beets. Parsnips and beets provide more folate than carrots. and may have potential in improving the health functionality of foods. Falcarinol may be involved in carrot and parsnip beneficial

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392 Vegetables of Temperate Climates: Carrot, Parsnip, and Beetroot

health effects including anti-inflammatory, antiplatelet as well as a variety of classes of phytochemicals associated with aggregation, and potential anticancer activity. While falcarinol optimal health. 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 See also: Antioxidants: Role on Health and Prevention; Bioavailability consumed or sensitization from oral intake. of Nutrients; Carotenoids: Occurrence, Properties and Determination; Parsnip leaves also contain furanocoumarins, which can Colors: Properties and Determination of Natural Pigments; Dietary Fiber: Determination; Functional Foods; Phenolic Compounds: cause photodermatitis if they are touched or brush up against the skin in the presence of light. Burns caused by these com- Bioavailability and Health Effects; Phenolic Compounds: Occurrence, pounds can be serious and can leave scars that do not easily Classes, and Analysis; Salad Crops: Root, Bulb, and Tuber Crops; disappear. Parsnips are therefore difficult to handle and indi- Sugar Alcohols; Tannins. viduals handling the crop require substantial protection during production. Parsnip root contains photocarcinogenic psora- lens, which are not destroyed by cooking. However, the effect Further Reading and potential toxicity of these chemicals from normal human consumption are not known. Arscott SA and Tanumihardjo SA (2010) Carrots of many colors provide basic nutrition Beet greens by weight have even more micronutrients than and bioavailable phytochemicals acting as a functional food. Comprehensive Reviews in Food Science and Food Safety 9: 223–239. beetroot, including vitamin A as b-carotene, vitamin C, vita- Christensen LP and Brandt K (2006) Bioactive polyacetylenes in food plants of the min K, calcium, iron, magnesium, potassium, copper, and Apiaceae family: occurrence, bioactivity and analysis. Journal of Pharmaceutical and manganese. Beet leaves also contain a substantial amount of Biomedical Analysis 41: 683–693. lutein and zeaxanthin and thus have health benefits associated Christiansen LP (2011) Aliphatic C17-polyacetylenes of the falcarinol type as potential health promoting compounds in food plants of the Apiaceae family. Recent Patents with those carotenoids as detailed earlier for carrots. on Food, Nutrition & Agriculture 3: 64–77. Beets are among the vegetables with the highest antioxidant Freidig A and Goldman IL (2011) Variation in oxalic acid content among commercial content. Betalain pigments are among the antioxidants in beets table beet cultivars and related crops. Journal of the American Society for and may be associated with cancer prevention. Betalains in Horticultural Science 136: 54–60. beet extract reduced tumors associated with skin and lung Gaertner VL and Goldman IL (2005) Pigment distribution and total dissolved solids of selected cycles of table beet from a recurrent selection program for increased cancer in mice, but no human studies have been done to date pigment. Journal of the American Society for Horticultural Science 130: 424–433. that demonstrate substantial health benefits. Betalains have a 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 required large nonpolar surface area that allows them to interact with for red betalain production. Nature Genetics 44: 816–820. lipid membranes and low-density lipoprotein particles in the Kanner J, Harel S, and Granit R (2001) Betalains. A new class of dietary antioxidants. blood reducing oxidation. Journal of Agricultural and Food Chemistry 49: 5178–5185.

Oxalic acid is related to the formation of kidney stones and Kapadia GJ, Tokuda H, Konoshima T, and Nishino H (1996) Chemoprevention of lung has other antinutritive properties. Table beet is considered a and 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 of high oxalate food, and therefore, breeding to decrease oxalic acid levels is an area of interest. In a collection of table beet antioxidant activities of common vegetables employing oxygen radical absorbance capacity (ORAC) and ferric reducing antioxidant power (FRAP) assays: a cultivars, mean values were from 722 to 1909 mg in 100 g of comparative study. Journal of Agricultural and Food Chemistry 50: 3122–3128. leaf tissue and 553 to 1679 mg in 100 g leaf tissue for total and Schmaelzle S and Tanumihardjo SA (2013) Chapter 2: Carrots of various colors. soluble oxalate levels, respectively. Root-soluble oxalate values In: Tanumihardjo SA (ed.) Carotenoids and human health, pp. 21–28. New York: ranged from 103 to 171 mg in 100 g of root tissue, and total Springer Science and Business Media. Simon PW, Tanumihardjo SA, Clevidence BA, and Novotny JA (2008) Role of color and values ranged from 95 to 142 mg in 100 g of root tissue. These pigments in breeding, genetics, and nutritional improvement of carrots. findings confirm relatively high levels of oxalate in table beet. In: Culver CA and Worlstad RE (eds.) Color quality of fresh and processed foods. Many people are familiar with ‘beeturia,’ or the excretion of ACS symposium series 983pp. 151–165. Washington, DC: ACS Books. red urine following beet consumption. This occurs in 10–14% Simon P, Bowman M, and Tanumihardjo SA (2013) Chapter 18: Horticultural crops as a of the population and seems to be a harmless idiosyncratic source of carotenoids. In: Tanumihardjo SA (ed.) Carotenoids and human health, pp. 293–301. New York: Springer Science and Business Media. reaction relating to digestion of the beet pigments. The occur- Stintzing FC and Carle R (2004) Functional properties of anthocyanins and betalains in rence of beeturia is probably related more to an individual’s plants, food, and in human nutrition. Trends in Food Science & Technology physiological conditions (such as stomach acidity), nutritional 15: 19–38. status, type of beet, and amount consumed, rather than genet- Tesoriere L, Allegra M, Butera D, and Livrea MA (2004) Absorption, excretion, and distribution of dietary antioxidant betalains in LDLs: potential health effects of ics as previously thought. betalains 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 of betalainic foods. Stability and bioaccessibility of betaxanthins and betacyanins and Summary antioxidative potential of food digesta. Journal of Agricultural and Food Chemistry 56: 10487–10492. Lucier, G. and Lin, B. H. (eds) (2007). Factors affecting carrot consumption in the Root vegetables are a source of energy in the form of carbohy- United States. USDA Economic Research Service. http://www.ers.usda.gov/media/ drates and a good fiber source. They contain essential nutrients 198875/vgs31901_1_.pdf.

The Encyclopedia of Food and Health, (2016), vol. 5, pp. 387-392