Download ppt - General Outline We will be looking at: ► Food Chemicals ► Detergents

General OutlineGeneral Outline

We will be looking at:We will be looking at:►Food ChemicalsFood Chemicals►DetergentsDetergents

These IncludeThese Include

Food ColoringFood Coloring

Flavorings and Flavorings and SweetenersSweeteners

Flour Improvers and Flour Improvers and BleachesBleaches

AntioxidantsAntioxidants

Preservatives and Preservatives and nutritional nutritional

supplementssupplements

SucroseSucrose

►Natural SweetenerNatural Sweetener► Adds to caloriesAdds to calories

Natural vs. ArtificialNatural vs. Artificial

Disadvantages of natural sweeteners:Disadvantages of natural sweeteners:►Adds to calories (hence unsuitable for Adds to calories (hence unsuitable for

people on a diet)people on a diet)► Increases blood sugar levels (hence Increases blood sugar levels (hence

unsuitable for diabetics)unsuitable for diabetics)

Natural vs. ArtificialNatural vs. Artificial

Advantages of Artificial Sugars:Advantages of Artificial Sugars:►Does not add to caloriesDoes not add to calories►Not metabolized in the bodyNot metabolized in the body► Inert, harmless Inert, harmless

SaccharineSaccharine

► Also known as Also known as ortho-ortho-sulphobenzimidesulphobenzimide

► Excreted in urineExcreted in urine► Inert in bodyInert in body

AspartameAspartame

Methyl ester of Methyl ester of aspartic acid-aspartic acid-phenylalanine phenylalanine dipeptidedipeptide

AspartameAspartame

As it is unstable at As it is unstable at high temperatures, high temperatures, it is unsuitable for it is unsuitable for cooking. Hence it is cooking. Hence it is used in cold drinks used in cold drinks and foods.and foods.

AlitameAlitame

►More stable than More stable than aspartameaspartame

► As it is 2000 times As it is 2000 times sweeter than sweeter than sucrose control of sucrose control of sweetness difficultsweetness difficult

SucraloseSucralose

► Tri-chloro derivative of sucroseTri-chloro derivative of sucrose► Same taste and appearance as sucroseSame taste and appearance as sucrose

► Stable at cooking temperatureStable at cooking temperature►Does not add to caloriesDoes not add to calories

Preservatives include:Preservatives include:

Table salt (NaCl)Table salt (NaCl)

SugarSugar

Preservatives include:Preservatives include:

Sodium BenzoateSodium Benzoate

And……And……

Salts of sorbic acid and propanoic Salts of sorbic acid and propanoic acidacid

Sodium BenzoateSodium Benzoate

►Metabolized in the Metabolized in the bodybody

► Used in limited Used in limited quantitiesquantities

Types of detergentsTypes of detergents

►SoapsSoaps►Synthetic detergentsSynthetic detergents

SaponificationSaponification

The general equation for The general equation for saponification is as follows:saponification is as follows:

Fat + Alkali Soap + GlycerolFat + Alkali Soap + Glycerol

SaponificationSaponification

Fatty acids used are:Fatty acids used are:►Stearic acidStearic acid►Oleic acidOleic acid►Palmitic acidPalmitic acid

The soap is precipitated with NaCl The soap is precipitated with NaCl (Why?)(Why?)

Varieties of soapVarieties of soap

Bath SoapBath Soap

► Better quality fat Better quality fat usedused

► Excess alkali Excess alkali removedremoved

► Perfumes and Perfumes and colors added colors added


Floating soapFloating soap

Air bubbles beaten in Air bubbles beaten in before hardeningbefore hardening


Transparent soapTransparent soap

► Soap dissolved in Soap dissolved in ethanolethanol

► Excess solvent Excess solvent evaporated offevaporated off


Medicated Soaps:Medicated Soaps:

Medicinal substances Medicinal substances addedadded


Shaving soap:Shaving soap:

►Glycerol added to Glycerol added to prevent dryingprevent drying

► Rosin added which Rosin added which forms sodium forms sodium rosinate which rosinate which lathers welllathers well


Laundry soap:Laundry soap:

Fillers like sodium Fillers like sodium rosinate, sodium rosinate, sodium silicate and sodium silicate and sodium carbonate addedcarbonate added


Soap chips:Soap chips:

Melted sheet of soap Melted sheet of soap run into a cool run into a cool chamber and soap chamber and soap scraped off in small scraped off in small broken piecesbroken pieces


Soap or scouring Soap or scouring powder:powder:

It consists of soap, It consists of soap, abrasives like abrasives like powdered pumice or powdered pumice or finely divided sand finely divided sand and builders like and builders like sodium carbonate sodium carbonate and tri-sodium and tri-sodium phosphate. phosphate.

Disadvantages of SoapDisadvantages of Soap

Soaps cannot work in hard water. This is Soaps cannot work in hard water. This is because hard water contains calcium because hard water contains calcium and magnesium ions. These react with and magnesium ions. These react with soaps to form insoluble Ca and Mg soaps soaps to form insoluble Ca and Mg soaps when soaps are dissolved in hard water.when soaps are dissolved in hard water.

The reaction is as follows:The reaction is as follows:

2C2C1717HH3535COONa + CaClCOONa + CaCl2 2 2NaCl + 2NaCl + (C(C1717HH3535COO)COO)22MM

M = Ca or MgM = Ca or Mg

Disadvantages of SoapDisadvantages of Soap

These separate out as scum and are These separate out as scum and are useless for washing. These make useless for washing. These make washing harder as they form a gummy washing harder as they form a gummy mass which adheres to cloth, mass which adheres to cloth, preventing cleaning action of soap preventing cleaning action of soap

Other Disadvantages of Hard Other Disadvantages of Hard WaterWater

►Hair washed in hard water looks dullHair washed in hard water looks dull►Dye does not absorb evenly on cloth Dye does not absorb evenly on cloth

washed with hard waterwashed with hard water

Advantages of Synthetic Advantages of Synthetic Detergents over soapsDetergents over soaps

►Have all the properties of soapsHave all the properties of soaps►Can be used in both hard and soft Can be used in both hard and soft

water to give foamwater to give foam►Gives foam even in ice-cold waterGives foam even in ice-cold water

Types of Synthetic Types of Synthetic DetergentsDetergents

►Anionic DetergentsAnionic Detergents►Cationic DetergentsCationic Detergents►Non-ionic DetergentsNon-ionic Detergents

Anionic DetergentsAnionic Detergents

Sodium salts of sulphonated long chain Sodium salts of sulphonated long chain alcohols or hydrocarbons. alcohols or hydrocarbons.

Alkyl hydrogensulphates made by treating Alkyl hydrogensulphates made by treating long chain alcohols with conc. Hlong chain alcohols with conc. H22SOSO44 and and then neutralized with NaOHthen neutralized with NaOH

CHCH33(CH(CH22))1010CHCH22OH OH HH22

SOSO44

CHCH33(CH(CH22))1010CHCH22OSOOSO33H(Lauryl hydrogensulphate)H(Lauryl hydrogensulphate)

NaOH (aq)NaOH (aq) CH CH33(CH(CH22))1010CHCH22OSOOSO33--NaNa++(Sodium (Sodium

lauryl sulphate) lauryl sulphate)

Anionic DetergentsAnionic Detergents

Anionic Detergents Anionic Detergents are mainly used in are mainly used in household cleaning household cleaning agentsagents

Cationic DetergentsCationic Detergents

►These are quaternary ammonium salts These are quaternary ammonium salts of amines with acetates, chlorides or of amines with acetates, chlorides or bromides as anions.bromides as anions.

► It is called cationic as the cationic part It is called cationic as the cationic part posses long hydrocarbon chains and posses long hydrocarbon chains and positive charge on nitrogen atom.positive charge on nitrogen atom.

E.g..: Cetyl tri-methyl ammonium E.g..: Cetyl tri-methyl ammonium bromide bromide

Cationic DetergentsCationic Detergents

Cationic detergents Cationic detergents have germicidal have germicidal properties and are properties and are expensive. These expensive. These are usually used in are usually used in hair conditioners.hair conditioners.

Non-Ionic DetergentsNon-Ionic Detergents

These detergents do not contain any ion These detergents do not contain any ion in their constitution.in their constitution.

CHCH33(CH(CH22))1616COOH + COOH + HO(CHHO(CH22CHCH22O)O)nnCHCH22CHCH22OHOH

-H-H22

OO CHCH33(CH(CH22))1616COO(CHCOO(CH22CHCH22O)O)nnCHCH22CHCH22OHOH

Non-Ionic DetergentsNon-Ionic Detergents

These detergents use These detergents use the same cleaning the same cleaning mechanism as mechanism as soaps.soaps.

Disadvantage of Synthetic Disadvantage of Synthetic DetergentsDetergents

If the detergent molecule is highly If the detergent molecule is highly branched, it is difficult to degrade by branched, it is difficult to degrade by bacteria, leading to accumulation in bacteria, leading to accumulation in the environment, i.e. they are non-the environment, i.e. they are non-biodegradable.biodegradable.