WO2012039599A2

WO2012039599A2 - Extraction of crude palm oil and phenolic compounds from oil palm fruitlets

Info

Publication number: WO2012039599A2
Application number: PCT/MY2011/000207
Authority: WO
Inventors: Mei Han Ng; Yuen May Choo; Ah Ngan Ma; Nu'man Abdul Hadi
Original assignee: Malaysian Palm Oil Board
Priority date: 2010-09-22
Filing date: 2011-09-22
Publication date: 2012-03-29
Also published as: WO2012039599A3; MY161468A

Abstract

The present invention relates to a process of sterilizing the oil palm fruitlets and extraction of crude palm oil as well as phenolic compounds from the said fruitlets. The process includes dry heating, i.e. microwave heating, of individual oil palm fruitlets and followed by extraction of crude palm oil from the dry heated oil palm fruitlets by way of solvent extraction. After the crude palm oil extraction, the oil palm fruitlets are subjected to a solvent for extraction of phenolic compounds. In this process, detachment of oil palm fruits from the bunch is not needed, thus power requirement will be much lowered and the extraction of crude palm oil will be more efficient. The extracted oil is rich in tocols with low free fatty acid (FFA) contents. The deoiled oil palm fruitlets are then subjected to an extraction process using suitable solvent to recover phenolic compounds which are normally found in palm oil mill effluent.

Description

EXTRACTION OF CRUDE PALM OIL AND PHENOLIC COMPOUNDS FROM

OIL PALM FRUITLETS

FIELD OF INVENTION

The present invention relates to extraction of crude palm oil and phenolic compounds from oil palm fruitlets.

BACKGROUND ART OF THE INVENTION

In oil palm milling, main objective of sterilization is to supply heat to (i) detach oil palm fruitlets from fresh fruit bunches (FFB) stalks, (ii) stop enzyme reaction that causes free fatty acids (FFA) in the oil palm fruitlets to rise and (iii) partially tear mesocarp of the oil palm fruitlets from kernel for subsequent cracking. Currently large quantity of steam is used to do the sterilization and prolonged steaming is necessary to allow sufficient heating of inner layers of bulky fresh fruit bunches (FFB). A complete sterilization cycle requires 70 to 90 minutes. Almost half of the steam used is exhausted during the sterilization cycle and the remainder steam ends up as sterilizer condensate and forms part of palm oil mill effluent (POME).

Conventional method in oil palm processing requires pressurized steam for heating whole FFB whereby the whole FFB gradually heats up from outer palm fruitlets to inner layer and centre core of the FFB. This conventional sterilization process is a wet process which requires high pressure steam i.e. at 40psi, 140°C in oil palm mill. The process is carried out on a batch basis where the FFB are loaded onto a cage and pushed into the sterilizer. Sterilization is needed to halt enzymatic reaction in the oil palm fruitlets to prevent any increase in the FFA content which is undesirable with respect to oil quality.

The conventional sterilization requires large amount of water to generate steam. It is estimated that for every tone of FFB processed, about 0.6 tonnes of condensate is produced. The steam also condenses on the oil palm fruitlets and hydrates them. Through steam heating, the oil palm fruitlets are further softened and mashed, which also mashes and partially tears mesocarp of the oil palm fruitlets from kernel. Crude palm oil is obtained through pressing by a screw press. Along with the crude palm oil, water and solids are also expressed in this pressing. The expressed crude palm oil from the screw press is pumped to a clarification tank where more hot water is added to reduce viscosity for more effective oil and water separation. For every one tonne of crude palm oil produced, about 1.5 tonnes of sludge is discharged from the clarification tank.

The large amount of water needed in the conventional crude palm oil processing poses environment concerns. In view of this, effort has been made to reduce if not eliminate altogether the water required for palm oil milling. Therefore there is a need for a process that reduces if not eliminates the water required for palm oil milling.

SUMMARY OF INVENTION

The present invention relates to a process for extracting crude palm oil from oil palm fruitlets. The process includes the steps of sterilizing the oil palm fruitlets using microwave heating, subjecting the sterilized oil palm fruitlets to non-polar solvent extraction using non-polar solvent and subjecting mixture of crude palm oil, non-polar solvent and oil palm fruitlets obtained above to at least one separation process to extract the crude palm oil. The microwave heating is performed using wavelength between 300MHz to 300GHz. The solvent used for the extraction of crude palm oil is selected from non-polar solvents such as hexane, heptane, cyclohexane, petroleum ether, dichloromethane or any combination thereof.

The at least one separation process includes the steps of (i) filtering mixture of crude palm oil and solvent and deoiled palm fruitlets from the mixture of crude palm oil, solvent and oil palm fruitlets and (ii) separating the solvent from the mixture of crude palm oil and solvent by distillation. The crude palm oil obtained has free fatty acid content between 0.5% to 2.5%, tocols content is between 700ppm to 2000ppm and Deterioration of Bleachability Index (DOBI) is between 3.0 to 5.0. Oxidative stability of the crude palm oil is high compared to crude palm oil obtained from conventional steam sterilization and screw pressing. The deoiled palm fruitlets obtained from step (i) are subjected to polar solvent extraction using polar solvent for recovery of phenolic compounds. The solvent used for the extraction of phenolic acids is selected from polar solvents such as ethanol, methanol, isopropanol, water or any combination thereof. Extraction of the phenolic compounds in a solvent can be aided with a hydrolysis reagent such as acids or alkali. Examples of acids are hydrochloric acid, sulphuric acid, etc. Examples of alkali are sodium hydroxide, potassium hydroxide, etc. The phenolic compounds contents are between l.Omg/g to 3.0mg/g. BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description given herein below and accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, wherein:

Figure 1 shows the flow of the process of extracting crude palm oil and phenolic compounds from oil palm fruitlets.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a process for sterilizing the oil palm fruitlets and extraction of crude palm oil as well as phenolic compounds from the said fruitlets. The sterilizing of the oil palm fruitlets involves dry heating, i.e. microwave heating, of the individual oil palm fruitlets followed by extraction of the crude palm oil from the said fruitlets by way of solvent extraction. In this process, detachment of oil palm fruitlets from the bunch is not needed, thus power requirement will be much lowered and the extraction of oil will be more efficient. The extracted crude palm oil is rich in tocols with low free fatty acid (FFA) contents. The deoiled oil palm fruitlets obtained after the extraction of the crude palm oil is then subjected to an extraction process using suitable solvents to recover phenolics compounds which are normally found in palm oil mill effluent. The oil palm fruitlets are individual fruits. It should be understood, however, that the disclosed preferred embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, the details disclosed herein are not to be interpreted as limiting, but merely as the basis for the claims and for teaching one skilled in the art of the invention.

Pre-treatment of the individual oil palm fruitlets is carried out to halt enzymatic lipolysis in the oil palm fruitlets. The pre-treatment is needed otherwise there will be an increase in the FFA content, which is an inferior oil quality indicator. The pre-treatment is known as sterilization process. The sterilization process is carried out via a dry heating, preferably microwave heating. This process of heating individual oil palm fruitlets enables halting of lipolysis without the need to detach the oil palm fruitlets from palm spikelets. As such, power needed for heating is much reduced. The microwave heating is performed using wavelength between 300MHz to 300GHz.

Through microwave heating, the oil palm fruitlets are partially softened and dehydrated. The oil palm fruitlets after microwave heating can be stored for up to seven days without rise in the FFA content of the extracted crude palm oil. When these partially microwave heated oil palm fruitlets are subjected to oil extraction using solvent, only crude palm oil is extracted and it dissolves in the solvent. A mixture of crude palm oil, solvent and oil palm fruitlets obtained from the extraction above is then subjected to at least one separation process to extract the crude palm oil. The at least one separation process includes the steps of:

i) filtering mixture of crude palm oil and solvent and deoiled palm fruitlets from the mixture of crude palm oil, solvent and oil palm fruitlets; and

ii) removal of the solvent by distillation to separate the solvent from the mixture of crude palm oil and solvent.

The crude palm oil obtained is not contaminated with palm kernel oil from kernel. The oil extraction using solvent is made possible by dehydration of palm mesocarp during the microwave heating. Softening of the mesocarp also eases tearing and mashing of the mesocarp from kernel. The solvent used for the extraction of crude palm oil is selected from non-polar solvents such as hexane, heptane, cyclohexane, petroleum ether, dichloromethane or any combination thereof.

Quality of crude palm oil obtained is superior, wherein FFA content is between 0.5% to 2.5%, tocols content is between 700ppm to 2000ppm, Deterioration of Bleachability Index (DOBI) is between 3.0 to 5.0 and oxidative stability is high compared to crude palm oil obtained from conventional steam sterilization and processing. The crude palm oil obtained through microwave heating and oil extraction using solvent contains higher amount of tocols than in crude palm oil obtained from conventional steam sterilization and screw pressing. Yield of the crude palm oil is between 25% to 50%.

After the filtering of the mixture of crude palm oil and solvent, the deoiled palm fruitlets are then subjected to phenolic compounds extraction using solvent. Thereafter, the deoiled palm fruitlets can be used directly as a solid fuel or raw materials for biomass derived products. The solvent used for the extraction of phenolic compounds is selected from polar solvents such as ethanol, methanol, isopropanol, water or any combination thereof. Extraction of the phenolic compounds in a solvent can be aided with a hydrolysis reagent such as acids or alkali. Examples of acids are hydrochloric acid, sulphuric acid, etc. Examples of alkali are sodium hydroxide, potassium hydroxide, etc. The phenolic compounds contents are between l.Omg/g to 3.0mg/g.

The examples presented below are included as an embodiment of the present invention but the examples are not intended to limit the scope of the present invention.

Example 1

The individual oil palm fruitlets are placed in an 800 watt, 2450 MHz microwave oven. Each dish of fruitlets is heated for 1, 2, 3, 4 and 5 minutes respectively. Table 1 shows the effect of microwave heating on individual oil palm fruitlets. Effect of microwave heating on the mesocarp and kernel of individual oil pali

Three minutes is deemed to be the optimum time required for microwave heating whereby there is no damage to the mesocarp and the kernel.

Example 2

Individual oil palm fruitlets are dry heated, i.e. microwave heating, as in Example 1. Extraction of crude palm oil from the heated oil palm fruitlets are carried out using hexane. Yield of the extracted crude palm oil and oil quality parameters are as shown in Table 2.

Table 2: Yield and quality parameters of crude palm oil extracted from microwave heated oil palm fruitlets

Heating Time Yield (%) Deterioration of Free Fatty

(min) Bleachability Acids (%)

Index (DOBI)

1 31 3.8 2.40

2 32 4.5 1.42

3 38 5.0 0.75 4 37 4.5 0.66

5 34 3.0 1.35

Example 3

Individual oil palm fruitlets with round shape are dry heated, i.e. microwave heating, as in Example 1. Extraction of crude palm oil from the heated oil palm fruitlets are carried out using hexane. Yield of the extracted crude palm oil and oil quality parameters are as shown in Table 3.

Table 3: Yield and quality parameters of crude palm oil extracted from microwave heated round shaped oil palm fruitlets

Example 4

Individual oil palm fruitlets with oval shape are dry heated, i.e. microwave heating, as in Example 1. Extraction of crude palm oil from the heated oil palm fruitlets are carried out using hexane. Yield of the extracted crude palm oil and oil quality parameters are as shown in Table 4. Table 4: Yield and quality parameters of crude palm oil extracted from microwave heated oval shaped oil palm fruitlets

Example 5

Individual oil palm fruitlets are dry heated, i.e. microwave heating, as in Example 1. Extraction of crude palm oil from the heated oil palm fruitlets are carried out using hexane. The tocols and carotenes content in the crude palm oil obtained are as shown in Table 5. Table 5: Composition of carotenes and tocols in crude palm oil extracted from microwave heated oil palm fruitlets

Heating Time Carotenes Tocols (ppm)

(min) (ppm)

1 639 1706

2 651 1916

3 678 1963

4 593 1688

5 621 1873 Example 6

Individual oil palm fruitlets with round shape are dry heated, i.e. microwave heating, as in Example 3. Extraction of crude palm oil from the heated oil palm fruitlets are carried out using hexane. The carotenes content in the crude palm oil obtained are as shown in Table 6.

Table 6: Composition of carotenes in crude palm oil extracted from microwave heated round shaped oil palm fruitlets

Example 7

Individual oil palm fruitlets with oval shape are dry heated, i.e. microwave heating, as in Example 4. Extraction of crude palm oil from the heated oil palm fruitlets are carried out using hexane. The carotenes and tocols content in the crude palm oil obtained are as shown in Table 7.

Table 7: Composition of carotenes in oil extracted from microwave heated oval shaped oil palm fruitlets

Heating Time Carotenes Tocols

(min) (ppm) (ppm)

1 682 1077 2 693 1117

3 709 993

4 866 1886

5 567 1039

Example 8

Individual oil palm fruitlets are dry heated, i.e. microwave heating, as in Example 1. Extraction of crude palm oil from the heated oil palm fruitlets are carried out using hexane. Oxidative stability of the crude palm oil extracted shows an induction period of over 20 hours.

Example 9

Individual oil palm fruitlets are dry heated, i.e. microwave heating, as in Example 1. Extraction of crude palm oil from the heated oil palm fruitlets are carried out using , hexane. Thereafter, the deoiled palm fruitlets are subjected to an extraction process for 2 hours using 60% ethanol in water with aid of hydrochloric acid for recovery of phenolic compounds. The total phenolic content in ethanolic extract is as shown in Table 8. Table 8: Total phenolics in ethanolic extract of microwave heated oil palm fruitlets

Heating Time Total Phenolics

(min) (mg/g)

2 1.15

3 1.13

4 1.13

Claims

1. A process for extracting crude palm oil from oil palm fruitlets, the process includes the steps of:

i) sterilizing the oil palm fruitlets using microwave heating;

ii) subjecting the sterilized oil palm fruitlets obtained from step (i) to non- polar solvent extraction using non-polar solvent; and iii) subjecting mixture of crude palm oil, non-polar solvent and oil palm fruitlets obtained from step (ii) to at least one separation process to extract the crude palm oil.

2. The process for extracting crude palm oil from oil palm fruitlets as claimed in claim 1 wherein the at least one separation process includes the steps of:

ii) separating the solvent from the mixture of crude palm oil and solvent by distillation.

3. The process for extracting crude palm oil from oil palm fruitlets as claimed in claim 2 wherein the deoiled palm fruitlets obtained from step (i) are subjected to polar solvent extraction using polar solvent for recovery of phenolic compounds.

4. The process for extracting crude palm oil from oil palm fruitlets as claimed in claim 1 wherein the oil palm fruitlets are individual fruits.

5. The process for extracting crude palm oil from oil palm fruitlets as claimed in claim 1 wherein the microwave heating uses wavelength between 300MHz and 300GHz.

6. The process for extracting crude palm oil from oil palm fruitlets as claimed in claim 1 wherein the non-polar solvent is hexane, heptane, cyclohexane, petroleum ether, dichloromethane or any combination thereof.

7. The process for extracting crude palm oil from oil palm fruitlets as claimed in claim 3 wherein the polar solvent is ethanol, methanol, isopropanol, water or any combination thereof.

8. The process for extracting crude palm oil from oil palm fruitlets as claimed in claim 3 wherein the polar solvent extraction is done with aid of a hydrolysis reagent.

9. The process for extracting crude palm oil from oil palm fruitlets as claimed in claim 8 wherein the hydrolysis reagent is an acid such as hydrochloric acid.

10. The process for extracting crude palm oil from oil palm fruitlets as claimed in claim 8 wherein the hydrolysis reagent is an alkali such as sodium hydroxide.

11. Crude palm oil extracted from oil palm fruitlets as claimed in claims 1 to 10.

12. Phenolic compounds extracted from oil palm fruitlets as claimed in claims 1 to 10.

13. The crude palm oil extracted from oil palm fruitlets as claimed in claim 11 wherein the crude palm oil has a content of tocols between 700ppm to 2000ppm.

14. The crude palm oil extracted from extracted from oil palm fruitlets as claimed in claim 11 wherein yield of the crude palm oil is between 25% to 50%.

15. The crude palm oil extracted from extracted from oil palm fruitlets as claimed in claim 11 wherein the crude palm oil has a content of free fatty acid between 0.5% to 2.5%.

16. The crude palm oil extracted from extracted from oil palm fruitlets as claimed in claim 11 wherein the crude palm oil has a Deterioration of Bleachability Index between 3.0 to 5.0

17. The phenolic compounds extracted from oil palm fruits as claimed in claim 12 wherein the extracted phenolic compounds has a content of phenolics between l.Omg/g to 3.0mg/g.