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AIMTo analyze some fruits & vegetables juice for the contents present in them.

INTRODUCTIONFruits and vegetable are always a part of balanced diet. That meansfruitsvegetables provide our body the essential nutrients,i.e. Carbohydrates,proteins, vitamins and minerals. Again their presencein these is beingindicated by some of our general observations, like -freshlycut applesbecome reddish black after some time. Explanation for it is thatiron presentin apple gets oxidixed to iron oxide. So, we can conclude thatfruits andvegetables contain complex organic compounds, fore.g., anthocin,chlorophyll, esters(flavouring compounds), carbohydrates,

vitamins and canbe tested in any fruits or vegetable by extracting out itsjuice and thensubtracting it to various tests which are for detection ofdifferent classes of organic compounds. Detection of mineralsin vegetables or fruits meansdetection of elements other thancarbon, hydrogen and oxygen.COMPONENTS OF FOOD1. Carbohydrates: Carbohydrates are poly-hydroxy-alcohols, which have analdehyde or ketones group. They have general formula CnH2nOn.Carbohydrates are the main source of energy 1 gm. ofcarbohydrates yield18 KJ of energy. The mono-saccharides serve as

building block. Glucose is also used in formation of fats & amino acids.2.Minerals: Minerals from 1-3% of the cell contents. Any marked changeinthe concentration results in the malfunctioning of cell & finally death.Somemineral present in the diet are:

(i) Calcium: It is the major component of bone & teeth. Calcium isrequiredfor blood clotting, muscle contraction, nerve impulse transmission

& heartfunctioning.(ii) Iron: Hemoglobin in our body contains iron which isthe universal carrierof O2& C02efficiency of iron causes anemia due to failure of hemoglobinsynthesis.THE FRUIT

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Development of fruit:After fertilization the ovary also begin to grow and gradually itmatures intothe fruit. The fruit may, therefore, be regarded as a mature orripened ovary.If, for some reason or other, fertilization fails, ovary simply

withers and fallsoff. A fruit consists of two portions, viz. the per carp (peri,round: karpos,fruits) developed from the wall of the ovary, and theseed developed fromthe ovules, apples, pineapples and some other fruitsthe ovary may grow intothe fruit without fertilization. Such a fruit is seedlessor with immature seedsand is known as the parthenocarpic fruit. Thepericarp may be thick or thin,when thick, it may consist of two or threeparts: the outer cell epicarp, fromthe skin of the fruit; the middle, calledmeson carp, is pulpy in fruits likemango, peach, plum etc. and the innercatted endocarp, is often very thinkand membranous, as in orange, or itmay be hard and stony as in manypalms, mangoes, etc. In many cases,

however, the pericarp is notdifferentiated into these three regions.Function of the fruit:The fruit gives protection to the seed and, therefore, to the embryo. Itstoresfood material. It also helps in dispersal of the seed. Normally it is onlytheovary that grows into the fruit; such a fruit is known as the truefruit.Sometimes, however, other floral parts, particularly the thalamus oreven thecalyx, may grow and form a part of the fruit; such a fruit is knownas thefalse fruit. Common examples of false fruits are apples, pear, cashewnut,

marking not, rose, dillenia, etc. In dillenia, the calyx becomes thickandfleshy forming the only edible part of the fruit.MATERIAL REQUIREDTest TubesBurner

Litmus paperLaboratory reagentsVarious fruits

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Vegetables juices

CHEMICAL REQUIREMENTSpH indicatorIodine solutionFehling solution A and Fehling solution B

Ammonium chloride solution

Ammonium hvdroxide

Ammonium oxalatePotassium sulpho-cynaide solutionPROCEDUREThe juices are made dilute by adding distilled water to it, in order to

removecolor and to make it colorless so that color change can be easilywatchedand noted down. Now test for food components are taken downwith thesolution.

TEST, OBSERVATION & INFERENCE

ORANGE JUICE

T E S T O

B S E R V A

T I O N I N

F E R E N C

E TEST FOR ACIDITYTake 5ml of orange juice in atest tube and dip a pH paper init. If pH is less

than 7 the juiceis acidic else the juice is basic. The pH comes out to be 6.OrangeJuice IsWeak Acid.

TEST FOR STARTCH

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Take 2 ml of juice in a testtube and add few drops of iodine solution. It turns blueblackin color than the starch ispresent.Absence of blue black incolor.Starch IsPresent

TEST FOR CARBOHYDRATES(FEHLINGS TEST)

Take 2 ml of juice and 1 ml of Fehling solution A & B and boilit. Red precipitatesindicate thepresence of producing sugarlike maltose, glucose, fructose&Lactose.No red colored precipitatesobtained.Carbohydratesabsent.

TEST FOR IRONTake 2 ml of juice add drop of conc. Nitric acid. Boil thesolution cool and add 2-

3 dropsof potassium sulpho-cyanidesolution .Blood red colorsshows thepresence of iron.A b s e n c e o f b l o o d r e dc o l o r . I r o n i s a b s e n t .

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TEST FOR CALCIUMTake 2 ml of juice addAmmonium chloride andammonium hydroxide

solution.Filter the solution and to thefiltrate add 2 ml of AmmoniumOxalate

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solution. White ppts.indicates the presence of calcium. Yellow precipitateisobtained.Calcium ispresent.

TOMATO JUICE

T E S T O

B S E R VA T I O N

I N F E R

E N C E TEST FOR ACIDITYTake 5 ml of orange juice in atest tube and dip pH paper in it.If pH is less

than 7 the juice isacidic and if the pH is morethan 7 the juice isbasic. T h e p H c o m e s o u t t o b e5 . T o m a t o j u i c e i s acidic.

TEST FOR STARCHTake 2 ml of juice in a test tubeand few drops of iodinesolution. If blue black

colorappears than starch is present.Absence of blue blackcolor.Starch ispresent.

TEST FOR CARBOHYDRATES(FEHLINGS TEST)Take 2 ml of juice and 1 ml of fehling solution A & B and boilit. Red precipitates

indicatesthe presence of producingsugar like maltose, glucose ,fructose &Lactose.Absence of red colorprecipitates.Carbohydrates arenot presentintomato.

TEST FOR IRONTake 2 ml of juice add drop of conc. Nitric acid boil thesolution cool and add 2-

3 dropsof potassium sulpho-cyanidesolution. Blood red colors showthe presence

of iron.Presence of blood redcolor.Iron is present.

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