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QUANTITATIVE TEST (CHEMICAL) FOR IN

Assignment title QUANTITATIVE TEST (CHEMICAL) FOR SUGARS IN SUGARCANE Submitted by Talha Saeed Roll # 37 Faisal Iftikhar Roll # 18 B.Sc. (Hons) Food Science and Technology 6thSemester (Regular) Subject FST – 507 Technology Submitted to Mam AMMARA AINEE Lecturer Institute of Food Science and Nutrition (IFSN) University of Sargodha, Sargodha

INSTITUTE OF FOOD SCIENCE AND NUTRITION (IFSN) UNIVERSITY OF SARGODHA SARGODHA

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QUANTITATIVE TEST (CHEMICAL) FOR SUGARS IN SUGARCANE

QUANTITATIVE TEST (CHEMICAL) FOR SUGARS IN SUGARCANE

In sugarcane the most abundant sugar present is . Sucrose is a which is made by the condensation of and . Types Of Sugars In Sugarcane There are two types of sugars present in sugarcane. Those are as under: 1) Reducing Sugars 2) Non-Reducing Sugars 1) Reducing Sugars Reducing sugars are sugars which have free aldehyde or ketone group. These sugars can react with other compounds and provide electrons to them. i.e glucose, , , , glyceraldehyde and many others. 2) Non-Reducing Sugars Non-reducing sugars are sugars which don’t have free aldehyde or ketone group. i.e sucrose and . Principle and Reagents Free aldehyde and ketone groups have the capability to change the color of copper solution to brick red and make it insoluble cuprous oxide. Sugar contents in food sample are estimated by determining the volume of sugar solution required to completely reduce the measured volume of Fehling’s solution. Copper Sulphate Solution (Fehling ‘A’) Copper sulphate (69.28g) was dissolved in distilled water in 1 lit. volumetric flask and makeup the volume to one liter solution. It is stored an amber colored bottle. Alkaline Tartarate Solution (Fehling ‘B’) Rochelle Salt (Potassium Sodium Tartarate) 346g and 100g sodium hydroxide were dissolved in one liter volumetric flask and final volume was made upto one liter with distilled water. It is also stored in an amber colored bottle. This solution keeps Cu2+ ions in solution form. Methyl Blue Indicator 1g of methyl blue was mixed with distilled water to make up the volume up to 100ml. Phenolphthalein Indicator 1g of dye dissolved in to make up the volume up to 100ml.

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QUANTITATIVE TEST (CHEMICAL) FOR SUGARS IN SUGARCANE

DETERMINATION OF REDUCING SUGARS

Reducing sugars that are present in are glucose and fructose. To determine reducing sugars following procedure is adopted: At first a sample of 10 ml sugarcane juice is taken, phenolphthalein indicator is added and titrated against 0.1 N NaOH. Once the neutralization completes add to clear the solution. Fehling solution is alkaline in nature and in order to titrate it with sugar solution we add citric acid. Apart from this, citric acid keeps the Cu2+ ions in available form. Distilled water is added to make the volume of solution up to 100ml. Now 5ml Fehling A solution and 5ml Fehling B solution are added together and heated till boiling occurs. At this moment fill the neutralized solution in burette. Add 2-3 drops of methylene blue indicator in the Fehling mixture and again start heating along with constant titration till end point, brick red is considered as an end point for this titration. Note the volume of neutralized solution used for titration. Reducing sugars reduces Cu2+ to Cu1+ that gives brick red color. Upon heating CuO and NaOH present in fehling solution dissociate that are responsible for this reaction:

2+ 2CuO ⇋ 2Cu + O2

NaOH ⇋ Na+ + OH-

Glucose Reaction

2+ - + 2Cu + 5OH → + Cu2O + 3H2O

Fructose Reaction

2+ - +2Cu +5OH → + CH2O + 3H2O

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QUANTITATIVE TEST (CHEMICAL) FOR SUGARS IN SUGARCANE

DETERMINATION OF TOTAL SUGARS

During the determination of total sugars the non-reducing sugars present in solution are inverted/ converted to reducing sugars by the action of citric acid and then above methods with some changes are used for determination of total sugars. The proper method for the determination of total sugars is as follow: First of all take 10ml sugarcane juice and add approximately 5gm citric acid (amount may vary) is added with 10 min boiling or leave the juice for 7 days. If citric acid is not available then HCl may be used for this. This addition of acid cause acid hydrolysis of sucrose and convert it into glucose and fructose.

+ + C12H22O11 +H + H2O → C6H12O6 + H (Inversion of Sucrose)

Citric Acid Dissociation

+ H3C8H5O7 + 3H2O ⇋ 3C6H5O7 + 3H3O

+ + 3H3O ⇋ 3H2O + 3H

After 7 days or boiling cool it and add phenolphthalein indicator and titrate it with 0.1N NaOH till end point. Once end point reaches dilution is done in order to make 100ml solution. Burette is filled with the diluted solution. Prepare mixture by adding 5ml fehling A and 5ml fehling B solution and heating till boiling. Once boiling starts add 2-3 drops of methylene blue indicator and start titrating it with solution present in burette. Titrate with constant heating till end point (brick red) and note the volume of solution used for titration. Calculation The formula used for the determination of sugars is

Total sugars or Reducing Sugars = 0.051 x Dilution factor x 100/Titrateable Volume Dilution factor = Final volume of solution after dilution/ volume of actual sample taken.

Non Reducing Sugars = Total Sugars – Reducing Sugars

It should be noted that results would be in percentages always. Other way to find non is its determination with the help of “High Performance Liquid Chromatography” and “Gass Chromatography”.

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QUANTITATIVE TEST (CHEMICAL) FOR SUGARS IN SUGARCANE

Disadvantages Of Chemical Method Some of the disadvantages of chemical method are as under: I. The results depend on the precise reaction times, temp and reagent conc. → must be carefully controlled. II. Cannot distinguishing bet different types of reducing sugar. III. Cannot directly determine of non-reducing sugars. IV. Susceptible to interference from other types of molecules that act as reducing agents.

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