A PROCESS FOR REFINING PALM-PRESSED FIBRE OIL (PPFO) TO PRODUCE REFINED OIL

AND THE REFINED OIL THEREOF

FIELD OF INVENTION

The present invention provides a process for refining palm-pressed fibre oil (PPFO) to produce refined oil and the refined oil thereof.

BACKGROUND OF INVENTION

Palm pressed-fibre (PPF) is a by-product obtained from the oil extraction process of oil palm fruits in palm oil mills. Conventionally, the PPF is burned as fuel to provide energy for the mill operations.

The residual oil extracted from PPF contains high concentrations of carotenoids, vitamin E and sterols (Choo et ai, 1996). The PPFO has been reported as a good source of health supplements to fulfil certain daily vitamin requirements including carotenes (pro-vitamin A), vitamin E (tocopherols and tocotrienols), squalene, sterols and phospholipids (Choo et al, 1996, 2003; Lau et al, 2008 and Rusnani et al, 2012). The phospholipids composition in palm-pressed fiber oil has also been well-studied and reported (Choo et al, 2004). All these studies had suggested that PPFO has a wide range of applications in pharmaceuticals, food and cosmetics industries.

Previous studies also found that the PPFO containing high amount of water-soluble compounds possess excellent antioxidant activities (Lau etal, 2007). Neoh et al (2011) found that the PPFO provides higher diacylglycerides, triacyglycerides and lauric acid as similar as palm kernel extracted by selective extraction methods, thus making its suitable in the food industry applications. The inherent properties of PPFO, enriched with desired nutritional attribute can be further developed into other high value-added products. However, the crude PPFO obtained from PPF cannot be used directly or blended into crude palm oil (CPO) without going through further processing.

Therefore, it is necessary to provide a process obtain speciality fiber oil products. Therefore, the present invention provides a refining technology for PPFO to enable greater market application of the oil and value addition.

SUMMARY OF THE INVENTION

Accordingly, the present invention provides a process for refining palm-pressed Fibre oil (PPFO) to produce refined oil, the process includes the steps of (a) water-degumming of the PPFO using water like distilled water at a temperature ranging from 70°C to 110°C preferably at 80°C for a period of less than 40 minutes, (b) acidic water-degumming of the PPFO using acid like phosphoric acid at a temperature ranging from 70°C to 110°C preferably at 80°C for a period of less than 40 minutes, (c) dry degumming of PPFO at a temperature ranging from 70°C to 110°C preferably at 80°C for a period of less than 40 minutes, (d) bleaching of PPFO using bleaching earth at a temperature ranging from 90°C to 115°C preferably at 105°C for a period of less than 40 minutes, (e) high vacuum deacidification of PPFO is conducted at a temperature less than 200°C and pressure less than 0.01 mbar, (f) dry fractionation of PPFO and (g) blending of refined PPFO olein with other oils.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following detailed description of the invention of exemplary embodiments of the invention in which is shown by way of illustration specific exemplary embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, but other embodiments may be utilized and other changes may be made without departing from the scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims.

In the following description, numerous specific details are set forth to provide a thorough understanding of the invention. However, it is understood that the invention may be practiced without these specific details. In other instances, well-known structures and techniques known to one of ordinary skill in the art have not been shown in detail in order not to obscure the invention.

Generally, the present invention provides a process for refining palm-pressed fibre oil [PPFO) to produce refined oil, the process includes the steps of (a) water-degumming of the PPFO using water like distilled water at a temperature ranging from 70°C to 110°C preferably at 80°C for a period of less than 40 minutes, (b) acidic water-degumming of the PPFO using acid like phosphoric acid at a temperature ranging from 70°C to 110°C preferably at 80°C for a period of less than 40 minutes, (c) dry degumming of PPFO at a temperature ranging from 70°C to 110°C preferably at 80°C for a period of less than 40 minutes, (d) bleaching of PPFO using bleaching earth at a temperature ranging from 90°C to 115°C preferably at 105°C for a period of less than 40 minutes, (e) high vacuum deacidification of PPFO is conducted at a temperature less than 200°C and pressure less than 0.01 mbar, CO dry fractionation of PPFO and Cg) blending of refined PPFO olein with other oils. PPFO is treated using a combination of processes comprising degumming and bleaching in order to the produce RPPFO. Acid degumming is applied to complete the degumming process followed by bleaching. Under selective bleaching conditions, all minor components such as carotenoids and palm vitamin E are reserved in the RPPFO. Different types of bleaching agents with various dosages in the range of 0.1 to 1.0 %wt are investigated. Significantly high amount of carotenoids is retained for all types of bleaching agents used in the bleached oil. Silica-based bleaching agent is found to reduce vitamin E content at high dosage treatment.

The process of the present invention may also include step of fractionation of refined PPFO to produce refined PPFO olein enriched with high concentration carotenes and vitamin E.

Besides that, the process of the present invention may also include step of blending of refined PPFO olein with refined, bleached and deodorised RBD palm olein (RBDPOo) and other refined vegetable oils e.g. canola, soyabean, rapeseed oils and others. In such a case, the blending ratio between refined PPFO olein with the RBDPOo and other refined vegetable oils e.g. canola, soyabean, rapeseed oils and others is more than 30% refined PPFO olein.

In this process, when distilled water is used in the process, dosage of the distilled water is less than 20%wt, and when phosphoric acid is used in the process, dosage of the phosphoric acid is less than l%wt. It is found that phosphorus content in the degummed PPFO reduced with increasing of water dosage during water-degumming step. The water used in the wet degumming can be either neutral or acidic. The contents of carotene and vitamin E in the degummed PPFO are not significantly changed after water-degumming. The Deterioration of Bleachability Index (DOBI) value of the degummed PPFO has been improved as compared to the crude PPFO. The dosage of bleaching earth is less than 2%wt. The bleaching earth is selected from natural bleaching earth, acid activated bleaching earth and silica based bleaching earth or any combination thereof. It is preferred that the PPFO used in the present invention to have DOBI value of more than 2.0 and/or to have phosphorus content value of less than 30 ppm and/or to have free fatty acid (FFA) value of less than 0.2%wt and/or to have the PFFO to be enriched with minor components such as carotenes and vitamin E.

The final stage of refining process is high vacuum deacidification in order to remove fatty acid and residual oxidation products under controlled conditions.

The RPPFO is further refined via fractionation process in order to produce refined red palm fibre olein (RRedPFO olein) fractions with high phytonutrients contents. The fractionated RRedPFO olein can then be blended with other oils to produce the red blended oil rich in carotenes and vitamin E.

Example 1

About 100 g of crude PPFO was weighed into a flask and heated under a nitrogen flow to 90°C. Approximately 0.5 to 10% of hot water [based on feed) was added to the mixture. The mixture was agitated at 90°C and hydrated of 20 minutes. The mixture was subjected to centrifuge at 2000 rpm for 15 minutes. The bottom layer was drained. The top layer was dried in the oven at 100°C for 24 hours. The samples were then tested for phosphorus content and DOBI value. The results were shown in Table 1. The DOBI of the water degummed PPFO has increased from 1.45 to 2.22. The phosphorus content can be reduced to about 20 ppm.

Table 1. Phosphorus content and DOBI value of degummed PPFO using hot water

Sample Water dosage Phosphorus DOBI

[v/w%) content [ppm)

Crude PPFO 0 636 1.45

Batch 1 0.5 498 1.78

Batch 2 1.0 421 1.80

Batch 3 2.0 387 1.81

Batch 4 3.0 305 2.06

Batch 5 4.0 279 2.16

Batch 6 5.0 57 2.20

Batch 7 10.0 20 2.22

Example 2

Following the method as described in Example 1, approximately 0.02 to 0.05% of phosphorus acid was added into hot water for degumming purpose. The samples were tested for phosphorus content and DOBI value. The results were shown in Table 2. It was found that the DOBI value increased with the increase of water dosage. Phosphorus content in the water degummed PPFO was reduced by 90% with addition of 10% water. Table 2. Phosphorus content and DOBI value of degummed PPFO using acidic hot water

Sample Water dosage Phosphorus DOBI

fv/w%) content (ppm)

Crude PPFO 0 205 1.35

Batch 1 0.5 102 1.55

Batch 2 1.0 82 1.60

Batch 3 2.0 73 1.71

Batch 4 3.0 56 1.78

Batch 5 4.0 41 1.87

Batch 6 5.0 30 1.94

Batch 7 10.0 23 2.11

Example 3

Following the method as described in Example 1, the water addition step was repeated two times using 5% hot water. The samples were then tested for phosphorus content and DOBI value. The results were shown in Table 3. Two steps of water degumming can effectively reduce the phosphorus content and increase the COBI value of the oil.

Table 3. Phosphorus content and DOBI value of degummed PPFO using two steps of hot water degumming

Sample Phosphorus DOBI

Content (ppm)

Crude PPFO 213 1.90

Step 1: Water-degumming 82 2.01

Step 2: Water-degumming 31 2.65 Example 4

Following the method as described in Example 1, the water-degummed fibre oil was subjected to dry degumming process by adding 0.05%wt of phosphoric acid in aqueous solution and heated to 90°C for 10 min. About 0.1%of bleaching earth was added to the mixture and stirred at 105°C for 15 min under nitrogen blanketing. The bleaching earth was filtered and the oil was dried under vacuum. The refined PPFO was analysed for its carotenes and vitamin E content. The results were shown in Table 4. The carotenes and vitamin E were retained in the water- degummed fibre oil.

Table 4. Carotenes and vitamin E content in the refined PPFO

Sample Water dosage Carotene Vitamin E fv/w%) content (ppm) (ppm)

Crude PPFO 0 1249 1205

Batch 1 0.5 1216 1093

Batch 2 1.0 1213 999

Batch 3 2.0 1248 949

Batch 4 3.0 1117 936

Batch 5 4.0 1190 893

Batch 6 5.0 1084 847

Batch 7 10.0 1082 840

Example 5

Following the methods as described in Example 1 and 3, the water-degummed Fibre oil was subjected to dry degumming process by adding 0.05%wt of phosphoric acid in aqueous solution and heated to 90°C for 10 min. About 0.1%of bleaching earth was added to the mixture and stirred at 105°C for 15 min under nitrogen blanketing. The bleaching earth was Filtered and subjected to high vacuum distillation using short path distiller at 180°C and 0.01 mbar. The reFined PPFO was analysed for the phosphorous content, DOBI, free fatty acid (FFA), carotenes and vitamin E content. The results were shown in Table 5. The carotenes and vitamin E were retained in the Final reFined PPFO. The FFA content was reduced to 0.15%wt. DOBI has been increased from 1.99 to 2.87.

Table 5. Phosphorous content, DOBI, FFA, carotenes and vitamin E content in the reFined PPFO

Sample Phosphorus Carotene Vitamin E DOBI FFA

Content Content

(ppm) [ppm) (ppm) (%)

Crude PPFO 113 1357 1105.5 1.9924 6.3914

Step 1: Water-degumming 100 1358 1097 2.6189 -

Step 2: Water-degumming 62 1323 1048 2.6544 -

Acid-degummed PPFO 64 1317 998 2.5807 -

Bleached PPFO 21 1208 904 2.8724 -

ReFined PPFO 20 1260 904 2.8724 0.1514

Example 6

Following method as described in Example 1, 5%wt of water was added during the water degumming process. The water-degummed oil was treated by dry degumming step using 0.05% of phosphorus acid at 90°C for 10 minutes. Approximately 0.1, 0.5 and 1.0%wt of bleaching agent was added into the mixture. The bleaching was carried out at 105°C for 20 min. The bleach bleaching agent was then Filtered under vacuum. The results were shown in Table 6. It was found that acidic and neutral earths have preserved the carotenes and vitamin E in the final PPFO. However silica-based earth has reduced the carotenes content.

Table 6. Effect of bleaching on carotenes and vitamin E contents in degummed and bleached PPFO

Total carotenes content Total vitamin E content

(ppm) (ppm)

Crude PPFO 1143 861

Bleaching agent

0.1 0.5 1.0 0.1 0.5 1.0

Dosage (%wt)

Acidic earth 1126 1143 1118 786 852 785

Natural earth 1132 1129 1120 797 814 672

Silica-based earth 1119 1142 1118 877 647 574

Example 7

The refined PPFO obtained in Example 5 was subjected to dry fractionation for cooling period of 10 hours. The final holding temperature was 24°C. The cooled refined PPFO was filter at pressure of 15 barg. The filtrate and solid were collected and analysed for their carotenes and vitamin E content. The yield of filtrate was 78% based on feed. The results were shown in Table 7.

Table 7. Carotenes and vitamin E contents of fractionated refined PPFO

Carotenes Vitamin E

Sample content Content

(Ppm) [ppm)

Refined PPFO 1260 904

Filtrate (liquid) 1462 1084 Cake (solid) 586 292

Example 8

The refined PPFO obtained in Example 7 was blended with refined, bleached and deodorised palm olein (RBDPOo) at ratio of PPFO to RBDPOo of 1:1, 2:1 and 1:2. The experiment was repeated by blending refined PPFO with refined canola oil at similar ratio. The blended oils were tested for their carotenes and vitamin E content. The results were shown in Table 8. The blended oils with different concentrations of carotenes and vitamin E were obtained.

Table 8. Carotenes and vitamin E contents of blended oils

Carotenes Vitmain E

Blended oils content Content

(ppm) (ppm)

PPFO:RBDPOo

Ratio 1:1 624 668

Ratio 2:1 842 724

Ratio 1:2 416 417

PPFO: Refined canola oil

Ratio 1:1 604 533

Ratio 2:1 816 647

Ratio 1:2 407 402