ACDIVOCA Nutrition Vegetables Softcopy

7/31/2019 ACDIVOCA Nutrition Vegetables Softcopy

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In recognition o the relation-ship between nutrition, agricul-tural science and market orces,the development communityis moving toward increasingly

integrated value chain devel-opment programming. Prac-titioners now must includenutritional considerations intocore agricultural developmentwork and measure nutritionalimpact. This act sheet is pro-duced as part o ACDI/VOCAsongoing learning agenda. Itis one in a series designed tobe a practical and inorma-

tive resource or sta on thenutritional value o crops andon leverage points within thevalue chains or maximizingnutritional impact.

Introduction

M

any countries have pri-oritized market devel-

opment o vegetablevalue chains based purely ontheir economic growth poten-tial. Compared to staple crops,vegetables typically etch high-er prices in the market, providea higher return on investment,are oten grown and/or soldby women, and can success-ully be produced on limitedamounts o land. Because o

their high nutritional content,increased access to a variety ovegetables is also a critical ele-ment o the nutritional security,developmental growth and

human productivity o a nation.However, research continues toshow that increased vegetableproduction does not lead toincreased household consump-tion. Hence it is important topair vegetable value chain workwith awareness-raising and be-havior-change activities to en-sure that producers themselvesare able to reap the nutritional

benets o what they grow.

Most vegetables contain sig-nicant amounts o vitamins,minerals and antioxidants, andcan improve diet diversity anda households nutritional statuswhen eaten in combinationwith staple oods. Improvingmicronutrient intake throughincreased vegetable consump-

tionwhether the vegetablesare grown on household armsor purchased in the marketiskey to tackling Aricas dualburden o undernutrition andincreasing rates o obesity.1

This act sheet provides inor-mation on the nutritional ben-ets o a number o commonlygrown vegetables in sub-Saha-

ran Arica. The purpose o thisoverview is to assist practitio-ners in the selection o veg-etables or value chain develop-ment and to inorm rotation,

intercropping and householdutilization choices that may bet-ter address nutritional decien-cies among arming amilies. Itcloses with several general tipson how to avoid loss o vitaminsand minerals during the production, harvesting, processing andcooking o vegetables.

Nutrition Integration Fact Sheet

Nutrition Integration Fact Sheet

VEGETABLES


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Vegetable NutritionalProfles

Three classes o vegetableswith high nutritional contentare proled below: dark-greenleay vegetables; orange, redand yellow vegetables; andpodded vegetables. See Figure1 or nutritional proles.

Dark-Green Leay Vegetables

The dark-green leaves o veg-

etables such as spinach, spi-der weed, pigweed, moringa,cassava and sweet potatoindicate a high vitamin andmineral contentspecically,vitamin A, iron and zinc. Thesevitamins and minerals are otenlacking in staple oods and areparticularly important or thehealth and development opregnant and lactating womenand children. Dark-green leayvegetables are great additionsto meals that are based on ce-

reals and legumes, but they donot store well and need to beeaten soon ater harvesting.

Orange, Red and YellowVegetables

These vegetables include someo ruit/fower vegetables aswell as root/tube/bulb vegeta-bles that are discussed in detailbelow. Vegetables and ruits oan orange color usually containa greater amount o vitamin A

Figure 1: Nutritional Profle

Crop Nutritional Profle

Dark-Green Leay Vegetables

Spinach Spinach has a high nutritional value, especially when resh, steamed or quickly boiled. Its ironcontent is twice that ound in other green vegetables, and the available iron is higher when eatenraw. It is also a rich source o olate, vitamins A, C, E, and K, magnesium, and antioxidants.

Spider plant/weed

Spider weed, also known as spider plant or Arican cabbage, is high in vitamins and minerals,especially vitamin A, vitamin C and iron. Spider weed can be sold as resh produce in markets,and it can be used to make medicinal products, insecticides and seed oils that are used in soaps,biouels or other commercial products.

Amaranthus

(Pigweed)2Amaranth has nutritional leaves and seeds, and it contains high levels o micronutrients such asvitamin A, vitamin C, iron and calcium in leaves, and high protein content in seeds. The leavesare also rich in lysine, an essential amino acid that is low or absent in cereals and tubers. Theprotein ound in young plants is important or people without access to meat or other sources oprotein. The at content in amaranth seed is high (78 percent), which is double that o commoncereals.

Moringa Moringa leaves contain high-level complete protein, vitamin A, B vitamins, vitamin C and miner-

als. Moringa is considered extremely valuable by people aware o its nutritional and pharmaceu-tical qualities. Moringa yields at least our dierent ediblespods, leaves, seeds and rootsandhas a potential role in reducing hunger, malnutrition, deorestation and rural poverty. In Arica,moringa leaves appear at the end o the dry season when there are ew other sources o leaygreen vegetables. Its leaves are developed into powder and ood additives, its pods can be pro-cessed like peas, its trunks are raw material or making paper and the tree can thrive in wasteland.3

Cassava leaves Cassava leaves contain carbohydrates as well as proteins and vitamin A. They are suitable orchildrens diets but must be cooked properly to remove toxins (e.g., through blanching).

Sweet potatoleaves

Sweet potato leaves provide a dietary source o protein, vitamins, minerals, antioxidants anddietary ber. These leaves are aordable sources o nourishment.


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Figure 1: Continued

Crop Nutritional Profle

Orange, Red and Yellow Vegetables:Fruit and Flower Vegetables

Tomato Tomato is botanically a ruit and rich in vitamin C, vitamin A, vitamin K, B vitamins and iron. It isalso a good source o the antioxidant lycopene, which is ound in the pigment that makes toma-toes red. The vitamin C content increases as the tomato ripens; this continues even ater harvest,but or optimal results, tomatoes should be vine ripened. Tomatoes can be preserved, althoughsome o the nutrients are destroyed during drying, canning or processing into a variety o prod-ucts such as tomato paste, tomato ketchup, tomato juice and sundried tomatoes.4

Pepper5 All peppers are a good source o vitamin A and C, although nutritional values vary depending on thevariety and stage o maturity. Bell peppers are usually picked beore they reach maturity, however i they arelet to ripen on the plant they are sweeter and higher in vitamin content. Other peppers (such as chili) areusually harvested at ull maturity. In general, peppers have a short storage lie o only one to two weeks.

Orange, Red and Yellow Vegetables: Root, Tube and Bulb Vegetables

Onion and

shallot6Onions and shallots contains a signicant amount o vitamin C, antioxidants and dietary ber.Farmers can extend the shel lie o onions by placing them in a warm, well-ventilated area untilthe necks and outer skins are thoroughly dry and brittle.

Carrots Carrots are an excellent source o vitamin A and contain a large amount o dietary ber andantioxidants. Under proper storage conditions (e.g., buried in light moist sand in an undergroundcellar or stored in the garden in a pit insulated with straw), carrots keep up to 4 to 6 months.

Potato7 Potatoes are a starchy vegetable and do not contain many vitamins or minerals. However, likestaple oods such as rice and maize they do provide a signicant amount o calories due to theirhigh carbohydrate content. Potatoes need to be stored in a cool, dark and well-ventilated place

and kept in perorated plastic bags or paper bags to keep them dry and to prevent sprouting.

Sweet potato The orange-fesh sweet potato is richer in vitamin A compared to other varieties, such as purple-or white-fesh sweet potatoes. Vitamin A bioortied orange-fesh potatoes have been developedand used in countries such as Uganda, Mozambique and Haiti. Sweet potatoes must be handledas little as possible to avoid scung and bruising. The storage lie o many varieties can begreatly increased by proper curing and/or storing in underground pits.

Cassava8,9 Cassava is a major source o calories or more than 250 million people in sub-Saharan Arica.However, a typical diet based on cassava provides less than 30 percent o the minimum dailyrequirement or protein and only 1020 percent o the required amounts o iron, zinc, vitamin Aand vitamin E. Moreover, because it carries low levels o a naturally occurring cyanide, cassava canbe toxic i is not prepared properly. Cassava needs to be supplemented by other nutritious oods

such as legumes and vegetables. Fresh cassava roots can be washed well, peeled, dried andground into cassava four, which has a long storage lie and multiple uses.10

Podded Vegetables

Okra11,12 Okra is a good source o vitamin B6 and olic acid and is rich in dietary ber. Fresh okra has ashort storage lie and needs to be kept dry. It should be loosely wrapped in perorated bags toprevent bruises. Okra can be dried and stored in baskets, clay pots or bags. Okra seed can alsobe dried, and the dried seed is a nutritious material that can be used to prepare vegetable curds,or roasted and ground to be used as a coee additive or substitute. Okra is considered to havediverse medical properties and and can be used to make items such as rope and paper.

Legumes Please reer to the legume act sheet


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than other colored vegetables.Vitamin A is a critical nutrientor vision, immune unction,

promotion o growth and skinhealth. Vitamin A deciency isprevalent in pregnant womenand young children in manysub-Saharan Arican and SouthAsian countries.

Root vegetables are plantroots used as vegetables. Theword root means any under-ground part o a plant.

Root vegetables are gener-ally storage organs, enlargedto store energy in the orm ocarbohydrates. They dier inthe concentration and the bal-ance between sugars, starches,and other types o vegetables.O particular economic impor-tance are those with a highcarbohydrate concentrationin the orm o starch. Starchy

root vegetables are importantstaple oods, particularly intropical regions, overshadow-ing cereals throughout much oWest Arica, Central Arica, andOceania. Examples include cas-sava, yams and sweet potatoes.

Podded Vegetables Poddedvegetables such as beans andpeas tend to be cool-season

crops. Podded vegetables areseeds that are ound insidetwo-sided pods. They are a richsource o proteins, potassium,olic acid, complex carbohy-drates, magnesium, iron, berand zinc.

Vegetable Rotationand Intercropping13

It is widely considered goodagricultural practice to rotateand intercrop certain comple-mentary crops in order toreplenish soil nutrients romone season to the next andto control pests. For examplebeans are oten planted atertomatoes to x nitrogen backinto the soil. By understandingthe nutritional elements and

agronomic properties o veg-etable crops, agriculture pro-grams can recommend bene-cial rotation and intercroppingchoices. This can increase oodavailability, diversity and acces-sibility or households.

In a rotation, vegetables areoten arranged according toamilies so that individual vege-

tables rom the same amily donot ollow each other. To keepa rotation sequence in properorder, it is best to intercropmembers o the same amilywhenever possible. Intercrop-ping involves the simultaneousculture o two or more cropsin the same garden within thesame growing season.

Techniques orReducing Nutrient Loss

The quality and nutritionalvalue o resh produce is a-ected by harvest methods,post-harvest handling and stor-age conditions, processing andpackaging. Poor preservationresults in waste during the in-

season, whereas during the o-season there is limited supplyaccompanied by high prices.

Appropriate preservation andstorage methods are neededto prolong the consumption onutrient-rich oods year round.The ollowing considerationsplay an important role in maxi-mizing nutrient retention:

Harvest: Picking too early ortoo late may have an impact onthe nutrient content o somevegetables.14

For example, crops such astomatoes and avocados areclimacteric, that is, they arecapable o generating the rip-ening hormone ethylene aterbeing detached rom the moth-er plant. Climacteric producemay reach ull ripe color evenwhen harvested early, yet theywill not reach the ull nutritiona

quality that they would havehad i they had ripened on theplant. Total vitamin C contento tomatoes, apricots, peachesand papayas is higher whenthese crops are picked ripe romthe plant. Other crops are non-climacteric, such as asparagus,peppers, lettuce, cucumber,eggplant, pumpkin and beets,which will reach commercialmaturity on the plant only.

I destined or distant markets,climacteric crops are oten har-vested as early as possible aterthey reach their physiologicalmaturity; this helps them with-stand mechanical harvestingand long-distance transportwithout damage. For householdconsumption rom home gar-


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dens, it is best to pick produceripe, right beore consumption,to ensure higher vitamin C and

other nutrient content.Harvesting should take place atcooler times o the day, such asthe early morning, to minimizenutrient loss and increase thework eciency o pickers.

Bruising and damaging as aresult o poor post-harvesthandling, exposure to tem-peratures and humidity, and

transportation can acceleratenutrient loss.

Processing and packaging15:Processing, such as cutting,slicing, chopping and peeling,can injure the plant tissues andinitiate deterioration (by enzy-matic reactions) and water loss-es. This increases susceptibilityto spoilage due to bacteria or

ungus growth and thus com-promises ood saety. It alsoalters chemical make-up andincreases nutrient loss. Preserva-tion methods include dryingand/or packaging in a timelymanner; blanching beore stor-age, packaging or reezing;irradiation; chemical preserva-tion (using ascorbic acid or cit-ric acid); or pickling with sugar

or salt. The ollowing are someuseul techniques:

Cooling slows physiologicalprocesses such as bacte-ria and ungus growth andspoilage. Lower storagetemperatures increase stor-age lie; blocking sunshineand allowing good air fowin storage spaces can help

reduce temperature.

Blanching is the heatingo ruits or vegetables or ashort time with either steamor water, and is an essen-tial step beore canning,drying or reezing o ood.Blanching inactivates cer-tain substances that wouldotherwise adversely aectnutrient content, color,favor or texture duringsubsequent processing andstorage. Blanching is useulor green beans, broccoli,asparagus and some othervegetables and ruits.

Canning, using either glassjars or tin cans, is one o themost eective ways to pre-serve vegetables. To avoidbotulism, special cautionshould be taken when can-ning low-acid oods such as

vegetables at home or on asmall-scale.

Protective packaging suchas liners, cushioning and indi-vidual wraps can reduce dam-age and vents in carton boxescan minimize heat buildup.

Cooking: Cooking methodshave an impact on nutrient

loss and nutrient distribution.Water-soluble micronutrients,such as vitamin C, B vitaminsand most natural orms ominerals, leak into the cookingwater. Reusing or drinking thecooking water in which leayvegetables are boiled can putthese nutrients to good use.Likewise, at-soluble nutrients,such as vitamin A, D, E, K and

most antioxidants, may dis-solve into the at portion o thedish (e.g., oil). For example,

deep-ried sweet potatoescontain much less vitamin Abecause vitamin A dissolvesinto the oil and is destroyed bythe high temperature o ry-ing. Baking or steaming sweetpotatoes will preserve more otheir Vitamin A.

Key Messages

Vegetable value chain ac-tivities must be combinedwith awareness-raising andbehavior-change activitiesto ensure that producersthemselves are able to reapthe nutritional benets owhat they grow.

The color o dark-greenleay vegetables indicates

a high vitamin and mineralcontentspecically, vita-min A, iron and zinc. Thesevitamins and minerals areoten lacking in staple oodslike rice and maize.

Orange, red, and yellowvegetables and ruits con-tain a large amount o beta-carotene (a plant-source

vitamin A), which is criticalor healthy vision, strongimmune unction, propergrowth and healthy skin.

Cassava and potatoes lackthe vitamins and nutrientsound in more colorul veg-etables. They most otentake the place o otherstaple oods and should


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1 See the Nutrition Primer, part o this series, or additionalinormation on macro and micronutrients and their aecton health and nutrition.

2

Pigweed http://www.botanicalsociety.org.za/ProjectsAn-dActivities/Useul%20Plants/Forms/DispForm.aspx?ID=4

3Lost crops or Aricavegetables. http://www.nap.edu/catalog.php?record_id=11763

4 Determinants o post harvest losses in tomato production: acase study o Imeko Aon local government area o Ogun state

5Pepper Fact Sheet. Ohio State University Extension.

6 Onions: post-harvest operations. FAO. http://www.ao.org/fleadmin/user_upload/inpho/docs/Post_Harvest_Com-pendium_-_Onion.pd

7Potato Nutrition Handbook. http://www.potatogoodness.com/Content/pd/PPNHandbook_Final.pd

8Biocassava Plushttp://www.danorthcenter.org/science/programs/INTERNATIONAL_PROGRAMS/BCP/deault.asp

9Impact o Cassava development on Food Security andNutrition o the Rural Poor http://km.ao.org/fleadmin/user_upload/sn/docs/SUMMARY_ImpactOCassavaDevel-opmentOnFSNoRuralPoor.pd

10Food storage and processing or household ood secu-rity http://www.ao.org/docrep/w0078e/w0078e07.htm

11 Okra. http://urbanext.illinois.edu/veggies/okra.cm

12An overview o Production, Processing, Marketing andUtilisation o Okra in Egbedore Local Government Area oOsun State, Nigeria. http://www.cigrjournal.org/index.php/Ejounral/article/viewFile/959/1119

13Vegetable Rotations, Successions and Intercroppinghttp://lubbock.tamu.edu/horticulture/docs/vegrote.html

14 Healthy and Sustainable Food http://chge.med.harvard.edu/programs/ood/nutrition.html

15Processing o horticultural products. http://www.ao.org/docrep/009/ae075e/ae075e22.htm

be eaten with legumes andother vegetables to maxi-mize nutritional benet.

In general, vegetablesdo not have a long useullie ater they have beenpicked, but their useulnesscan be extended by curing,drying, or using appropriatestorage methods.

To maximize soil health,vegetables rom the sameamily should be inter-

cropped together, andvegetables rom a dierentamily should ollow duringthe next crop rotation.

Most ruits and vegetableshave greater vitamin con-tent i they are picked ripe

rom the plant, rather thanbeing picked beore theyhave ully ripened.

Cooking methods have animpact on how much o avegetables nutrients canactually be consumed.

Vitamin C, B vitamins andmost natural orms ominerals will leak into the

cooking water. Reusing ordrinking the cooking waterin which leay vegetablesare boiled can prevent theloss o these nutrients.

Vitamins A, D, E, K andmost antioxidants maydissolve into cooking oil.

For example, deep-riedsweet potatoes containmuch less vitamin Abecause vitamin A dis-solves into the oil and isdestroyed by the hightemperature o rying.

Producer and consumer ed-ucation is key to increasedconsumption o nutritiousoods. Using proper incen-

tive strategies, other marketactors (e.g., input suppliers,retailers, etc.) can also playan important role in educa-tion and behavior change.

ACDI/VOCA is an economic development organization that ostersbroad-based economic growth, raises living standards and creates vibrantcommunities. ACDI/VOCA has worked in 145 countries since 1963.

Visit us at www.acdivoca.org.

ACDIVOCA Nutrition Vegetables Softcopy

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