Shes 3310 Part 3 English Latest.ppt

Modifications of Palm Oil

23.10.2013

Modifications increase their usability. 2/3 of oil for food uses

1/3………………as non-food uses Egs of food uses: As cooking oil, margarine, vegetable ghee, confectionary fats, ice cream, shortenings,

non-dairy creamers, Non-food uses: Soaps, epoxidised palm oil, palm based oleochemicals, alpha-sulphonated methyl esters, palm based diesel substitute

In its natural form, TAG composition is according to the need of the plant.

The compositions of oil and fat need to be modified for human consumption. 5 methods are employed: 1. 2. 3. 4. 5.

Chemical modifications Main method Physical Enzyme “selective breeding” -Planting of wild species -by microbial techniques Genetic engineering

1. Chemical Modifications

i) Intraesterification The fatty acid is reorganized within the TAG molecule to form 3 new TAGs. In the presence of catalyst. S (18:0) (18:0) O

O L

L (18:2)

L +

S

O

L +

S

S O

ii) Transesterificaton includes chemical reactions where an ester is reacted with the following to generate a new ester a) alcohol (alcoholysis)

b) acid (acidolysis) c) another ester (intereseterification or ester exchange)

a)

Alcoholysis

Fig. Methanolysis of oil for the production of fatty acid methyl ester.

When methanol is used in alcoholysis, the reaction is called methanolysis. Fatty acid methyl esters produced can be used as an alternative fuel for diesel engine (biodiesel). Biodiesel is a substitute or extender for traditional petroleum diesel. It can be used in conventional diesel engines, and the use of biodiesel is advantageous for reducing emission of CO2, CO, SO2 and particle materials. Biodiesel is now spreading world wide. For example, in France, all the diesel fuel marketed contains 5% of biodiesel.

Glycerolysis is another eg of alcoholysis. -TAG is reacted with glycerol (alcohol) in the presence of alkaline catalyst to form partial glyceride such as monoacylglycerol. - A mixture of triacylglycerol and glycerol are heated at 200250°C in the presence of sodium hydroxide. The resulting main product is monoacylglycerol, which is used as food emulsifier after purification by molecular distillation.

Figure. Glycerolysis. In practical process, the product is a mixtureof mono-and diacylglycerols.

b) Acidolysis An industrial application of acidolysis is production of long chain fatty acid vinyl esters from vinyl acetate and fatty acids. Long chain fatty acid vinyl esters are industrial raw material for making plastics

Figure: Production of fatty acid vinyl ester by acidolysis.

c) Interesterification of oil changes its molecular composition. Oils or fats are mixture of various triacylglycerol molecules having different fatty acids and positional distribution.

Treating oils and fats with sodium methoxide as a catalyst at 80 °C causes intermolecule ester exchange, changing the molecular composition, while leaving the fatty acid composition

unchanged. As a result, the oil changes its physical properties such as melting point and consistency.

• An important application of interesterification is

improvement of natural lard (pig fat). Natural lard tends to form a rough crystal, which is difficult to handle, during storage. This is because 64% of palmitic acid is attached to 2nd position of triacylglycerol molecules. Randomizing the positional distribution of fatty acids of natural lard by interesterification improves its physical property, making it a smooth “rearranged lard”.

• Another example of interesterification is in the field of margarine production. Interesterification of soybean oil and completely hydrogenated soybean oil provides a material for margarine. This rearranged oil has an advantage that it does not

contain trans fatty acid, because it is not made through partial hydrogenation.

Figure: Interesterification of triacylglycerol molecules. Fatty acid distribution is randomized,resulting in change of the physical property of the oil.

Types of catalyst used in interesterification: Chemical catalyst: Na/K alloy 0-40ºC NaOMe 60-90ºC Na 130ºC NaOH/Ethylene glycol 150ºC Amount of catalyst 0.2-0.4% reaction time 30-60 mins Use pure oil

iii) Hydrogenation – Production of semi solid fat. – Hardening process – Used to produce margerine, shortenings and specialty fat depending on extent of hydrogenation H

H

Oleic acid + H2

H

H

H2

Stearic acid (18:0)

- Catalyst platinum dan nickel. - Some trans fatty acid are also produced. Cis converted to trans in the presence of heat or in the presence of energy. Trans fatty acid behave like saturated fatty acid. Associated with Coronary diseases. - Change in physical characteristics of oil from liquid form to solid form. - Eg: palm oil (through partial hydrogenation) produces margerine (semi soild form)

2. Physical Methods

 Blending Two or more types of oil is blended in a certain ratio to produce a new type of oil.

No chemical rx is involved The

new

oil

has

the

required

characteristics for a certain purpose.

physical

Examples: a) As cocoa butter substitute, cocoa butter replacers and cocoa butter equivalent • Fractionation result in several grades of ‘palm midfractions’ containing different constituents of fat

(TAG) with varying ‘melting characteristics’ • A suitable fraction can be used as cocoa butter substitute and cocoa butter equiv in

cakes, chocolates and confectionary.

Cocoa butter equivalent (CBE). • An all vegetable, non-hydrogenated product

containing almost the same fatty acids and glycerides present in a typical cocoa butter. Thus physical characteristics almost the same. May be added to cocoa butter in any amount. • Prepared by blending, fractionation and interesterification. Generally based on shea oil, illipe oil and palm oil. Cocoa butter(CB)

If blending using palm oil, main component is palm mid fraction (high in 2-monounsaturated glycerides

ie SUS). Compatible with cocoa butter.

Chemical composition of cocoa butter: Fatty Acid Composition of Cocoa Butter (%) Myristic

0.2

Palmitic

26.0

Palmitoleic

0.3

Stearic

34.5

Oleic

34.5

Linoleic

3.5

Arachidic

1.0

Saturated

61.5

Monounsat

35.0

Polyunsat

3.5

Malaysian Palm Oil Promotion Council by John M. deMan and Leny deMan pg1

Triglyceride Composition of Cocoa Butter Ghana

Malaysia

Brazil

Symmetrical monounsaturated (POS, SOS, POP). Major component of cocoa butter is POS

80

87

72

Symm. diunsaturated

9

7

8

Unsymm. diunsaturated

8

5

17

Polyunsaturated

3

1

3

Symm monounsat TAG have unsat fatty acids in the 2-postn and sat fatty acids in the 1- and 3- postn. These include POS, SOS, POP with POS largest amount.

Cocoa butter substitute (CBSs) These are plant fats containing lauric and myristic acids, with some physical similarities but chemically totally different from cocoa butter; due to this they are suitable only for whole replacement of CB-cannot be mixed with cocoa butter.

TAG constituents???

Cocoa Butter Replacers (CBRs) Are non-lauric plant fats with a distribution of fatty acids similar to that of CB but a completely different TAG structure; thus may be added in small amount only to CB. Based mainly on palm kernel oil or coconut oil.

Obtained by fractionation, blending, hydrogenation, interesterification or a combination of these. Have snap and melting properties comparable to

cocoa butter but a different chemical composition.

b)

Ghee Originally produced from animal fat. Now produced from palm oil alone or blended with other

types of vegetable oil – vegetable ghee. No heat involved , thus no formation of trans fatty acid. c)

Ice Creams Mixture of palm oil and PKO replaces milk fat for the preparation of ice cream. A smooth structured ice cream with excellent eating qualities is easily produced by this substitution.

c) Non dairy creamers.

Blend of: i) Palm oil ii) PKO

iii) Other vegetable oil Creamer is used to replace milk.

3. Enzyme Method  Enzyme lipase is used Result in: i) inter and intra esterification of TAG ii) hydrolysis of TAG.  Hydrolysis TAG

Fatty acid and glycerol.

Water content must be controlled. If water

content low, reversible rx. may occur.

28.10.2013

Reactions catalyzed by lipases: Lipases (and esterases) catalyze three types of reactions (Figure 4-1-1). i) Hydrolysis ii) Ester synthesis

iii) Transesterification Transesterification is categorized into four categories. 1) Alcoholysis is the reaction of an ester and an alcohol.

2) Acidolysis is the one with an ester and an acid. 3) Interesterification is a reaction between two different esters, where alcohol and acid moiety is swapped. 4) In aminolysis, an ester is reacted with an amine generating an amide and an alcohol.

ester

Alcohol

alcohol

Acid

Acid

Ester

Figure 4-1-1: Types of reactions catalyzed by lipases

Ester

Ester

Ester

Types of reactions catalyzed by lipases

• Differences

between

chemical

and

lipase-catalyzed

reactions.

i) lipase-catalyzed reactions can proceed under milder conditions than the chemical reactions. ii) More importantly), the lipase-catalyzed reactions are

specific (or selective) for a particular acyl groups (differing specificities towards fatty acid), particular positions of the substrates (regiospecific), or particular stereoisomers.

Example: Pancreatic lipase 1,3-specific Fungal lipase has preference for MUFA (monounsaturated fatty acids).

Interesterification Results In change in Melting Points of Oil Blend a

Blend b

Before

After

Before

After

10º

80

87

73

83

20º

62

61

58

53

30º

33

24

22

12

35º

28

6

19

1

40º

22

0

16

0

a = Hydrogenated Palm Oil (30%) and PKO(70%) b = Hydrogenated rapeseed oil (20%) and PKO (80%)

• Due to enzyme regiospecificity, enzyme catalysed interesterification is commercially utilised. • Usually the enzyme lipase is adsorbed on to adsorbents like kieselguhr, hydroxylapatit, alumina, resin phenol-formaldehyde; add some water, Temp 40 – 80ºC; 16 – 17 hrs. Oil1/Fat1 + Oil 2/Fat 2 Oil1/Fat1 + fatty acid Oil1/Fat1 + methyl esters If: Oil/Fat + acid Esterification thro acidolysis

Lipase Sources for Interesterification Unspecific

1,3-spesific

9-spesific

Candida cylindricae

Aspergillus niger

Geotrichum candidum

Corynebacterium Mucor javanicus acnes Mucor miehei

Staphylococcus aureus

Rhizopus arrhizus

Rhizopus delemar Rhizopus niveus

Some egs of interesterification Lipase-catalysed synthesis of equivalent.

and acidolysis. Cocoa butter

i) Sunflower Oil/safflower oil + ethyl stearate Rhizopus niveus TAG (symmetrical) (80%) consisting of St

P

P

O

O

O

St

St

P

Main (Utama)

• Substitute for ‘cocoa butter’ in chocolates, confectionary and cakes.

ii) Vegetable oil + fatty acid (food grade) Asperillus oryzae

For chocolates and confectionaries

iii) “Palm mid-fraction”

+

(rich in SUS like POP 58%,

POSt 13% and StOSt 2%)

stearic acid Rhizopus niveus acidolysis

POP 9%, POSt 32%, StOSt 32% (similar to cocoa butter) NB : S=Saturated (Tepu) U=Unsaturated (Tak tepu) St=stearic acid

Palm mid fraction is a specialty fat produced

by multiple fractionation of palm oil. High content in POP.

iv) Sunflower Oil (high in oleic) + Stearic acid acidolysis Mucor miehei

v) Palm oil + tristearin Interesterification

StOSt (79%)

Mucor miehei

POP(12%) + POSt(35.7%) + POO(4.8%) + StOSt (38.2%) + StOO (9.3%)

Lipase (0.09g), palm oil (60 µL), 0.09g tristearin. Rx in supercritical carbon dioxide, 50˚C for 3 hrs. Gave best yield of cocoa butter equiv in comparison to other oils.

Sample question. The fatty acid triacylglycerol composition of oils can be transformed through interesterification using enzymes. What product arises from the interesterification of sunflower oil (high in oleic acid) and ethyl stearate in the presence of Rhizopus niveus? What is the importance of the product that arises from this reaction?

4.

Selective Breeding

a) Use of classic technique of plant biology. Breeding of plant through many generations. 

At each generation, the required phenotype is selected and bred for many generations to

produce the perfect plant with the desired characteristics. 

Time

too

successful.

long

but

the

method

is

highly

Rapeseed oil usually contain high erusic acid – not suitable for animal feed.

Plants with low erusic acid is produced through this method of breeding. To speed up the selective plant breeding technique, the mutation method is employed.  radiation is used. Refs: http://www.asd-cr.com/ASD-Ing/Breeding.htm

b) Breeding of Wild species •

•

Cuphea spp. oil contain short chain and medium chain fatty acid (Canada). Cuphea painteri : 8:0 65% Cuphea lanceolata : 10:0 83% Cuphea melanium : 12:0 36% Cuphea palustri : 14:0 64% Meadowfoam (Linnanthes alba), North America. 5 – 20 : 1 63% ; 5 – 22 : 1 4% ; 13 – 22 : 1 10% ; 5,13 – 22 : 2 18% ; Double bond at C5 and 13 Chain made up of 22 carbons

c) Through Microbes Several microbes has high content of specific fatty acids for eg:  Mortierella alpina (fungi) has arachidonic acid, 40%.  Crypthecodinium

cohnii

(alga)

contain

40%

docohexaenoic acid (DHA). DHA is incorporated in infant’s milk formula. Good for development of brain.

5. Genetic Engineering

 Modern technique whereby the required genes are transferred into a plant to produce a particular type of oil.

 Also known as Recombinant Technology.

Three factors are necessary: i. Basic knowledge of a plant’s lipid content. For eg: Why does oil palm produces oil with a high content of palmitic acid (16:0)? The enzyme Acyl-ACP thioesterase which releases fatty acids from the fatty acid synthethase complex

has specificity for palmitic acid. Thus the acid is released and is not extended.

ii. Gene Transfer System A biological system which can carry foreign genes in a plant cell is required. For example, the bacteria agrobacterium sp is capable of infecting many plants enabling gene transfer to take place. Once a gene has been transferred to a cell, the gene can be inoculated into the genome of a receiving plant.

iii.Degeneration system The genes must be inherited by the following generation and subsequently expressed.

Sample Question. Modifications increase the usability of an oil or fat. The fatty acid triacylglycerol composition of oils can be transformed through various techniques. Describe three of these modifications and name the products obtained.

Ans. i) Bet TAG and methanol. Methanolysis. Need to show reaction. Product FAME. ii) Rx of suitable enzyme with Palm mid fraction result in cocoa butter equivalent. Need to show reaction. iii)Hydrogenation of TAG. Need to show rx. involved. Product margerine. iv) Saponification. Rx bet TAG and KOH or NaOH. Need to show rx involved. Product soap. Other examples are also accepted