FIELD OF THE INVENTION

This invention relates to a process for extracting palm products from oil palm fresh fruit bunches. More specifically, the invention relates to a new process for extracting high quality palm oil with improved oil and kernel extraction rates and less pollution than conventional processes.

BACKGROUND OF THE INVENTION

The conventional process for the extraction of palm oil uses basic technology developed some 70 years ago in Africa. This process is complex and has many steps. A simplified conventional palm oil extraction process is shown in Figure 1. Fresh fruit bunches (FFBs) are cooked during sterilization using steam at a pressure of up to 3 bars gauge in horizontal cylindrical autoclaves for about 90 minutes. Then the sterilized fruit bunches are transferred to a drum stripper. The drum is rotated to separate the sterilized fruits from the sterilized fruit bunches. The sterilized fruits are then transferred into steam-heated vessels known as digesters where they are subject to a series of rotating blades normally in the presence of live steam to separate the mesocarp from the nuts. The digested mash (fibres, nuts, oil and water) are then passed into a screw press for pressing. The screw press expels the mixture of oil, water and finely divided solids through the perforations of the screw press cage while at the same time discharging the solid press cake comprising of fibre and nuts into a conveyer for further processing. The expelled oil mixture (the underflow) from the screw press is diluted with hot water before it goes through a vibrating screen to remove some of the larger solids which are recycled to the digesters. The screened underflow is further injected with live steam in the crude oil tank and heated to above 90°C before being pumped into the clarification tank. In the clarification process, it is left to settle by gravity for 3 to 4 hours into two layers - oil and sludge. The oil layer in the clarification tank is skimmed off and passed to a purifier which reduces the dirt content to 0.01 percent or less. The purified oil is then dried in a vacuum dryer to give a product of crude palm oil with a moisture content of approximately 0.15 percent. Sludge from the clarification tank still has approximately 4 to 10 percent of free oil. The oil is recovered usually after de-sanding using a centrifugal separator. The oil recovered by the centrifugal separator contains some water and dirt and is therefore returned to the clarification tank for further treatment. Separator sludge will be discharged continuously as Palm Oil Mill Effluent (POME) together with waste water from other sections of the mill. The conventional milling process generates about 0.7 tons of POME for each ton of FFB processed. POME is the one of the main causes of environmental pollution due to its high Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand. Treatment of the POME is a major issue for the mills. There have not been any major developments to the existing process and the conventional process has remained unchanged for about 70 years.

The European Food Safety Authority (EFSA) has found that palm oil contains the highest levels of monochloropropane-l,2-diol (3-MCPD) and glycidyl fatty acid esters (GE) contaminants among all vegetable oils. EFSA have set 3-MCPD and GE safety limits for 2018 at 1.0 mg/kg and 0.5 mg/kg respectively. The current palm oil industry averages for 2016 was 2.9 mg/kg for 3-MCPD and 4.0 mg/kg for GE. As such, there is a need for an invention that overcomes said problems faced by the industry, to improve the existing process of processing oil palm fruits and to improve the quality and yield of the fruits.

SUMMARY OF THE INVENTION

The present invention is directed to a novel process of extracting oil palm products such as palm oil, palm kernels, fibres and shells from oil palm fruits. The process utilizes substantially clean oil palm fruits and comprises the steps of softening the mesocarp of the oil palm fruits, digesting the softened oil palm fruits and separating the palm oil from the digested oil palm fruits. These substantially clean oil palm fruits have a low impurity percentage of 10% or less and are preferably substantially uncooked prior to subjecting the fruits to the process as disclosed in the invention to extract palm oil. Substantially clean fruits which are cooked can also be used for this process.

In addition, palm nuts can be extracted at any stage of the process wherein the process further includes the steps of isolating the oil palm nuts from the oil palm fruits, drying the oil palm nuts, cracking the dried oil palm nuts, extracting palm kernels and shells from the cracked oil palm nuts and drying the obtained palm kernels. The process, compared to the conventional process, requires no vibrating screen, addition of hot water, clarification, de-sanding and de-stoning. The process also provides a use of simpler and smaller machinery thus allowing the process to be performed on at least one mobile unit. The use of mobile units allow palm oil traceability as well as reduced transportation costs. The process also has higher oil extraction rate (OER) and higher palm kernel recovery.

The present invention discloses a process which provides an option to extract food-safe virgin palm oil with the use of food-safe equipment during the softening, digesting and/or separating step. In addition, this process does not require pressurized steam and palm oil can be extracted at lower than conventional milling temperatures. For example, 90°C or less. Palm oil extracted using this invention also has a significantly higher Deterioration of Bleachability Index (DOBI) and lower free fatty acid content. Low free fatty acid (FFA) combined with low temperature extraction will reduce formation of mono and di-glyceride which are the precursors to 3-monochloropropane-l,2-diol (3- MCPD) and glycidyl acid (GE).

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is illustrated, though not limited, by the following detailed description of embodiments that is given by way of example only with reference to the accompanying drawings. In the drawings:

Figure 1 illustrates the simplified conventional palm oil extraction process oil as described above.

Figure 2 illustrates how to obtain substantially clean fruits from the FFB.

Figure 3 illustrates the new palm oil extraction process in accordance with one

embodiment of the present invention with nut isolation after the softening step.

Figure 4 illustrates the processing of oil palm nuts to extract kernel in accordance with an embodiment of the present invention.

Figure 5 illustrates the new palm oil extraction process in accordance with another embodiment of the present invention with nut isolation after the digesting step.

Figure 6 illustrates the new palm oil extraction process in accordance with another embodiment of the present invention with nut isolation after the separating step.

Figure 7 illustrates a Venn diagram of a typical FFB sent to a mill. Circle A (smaller circle) represents components of FFB and Circle B (bigger circle) represents non-oil bearing items. Impurity is represented by the shaded region.

Figure 8 illustrates an example of a typical detachment and cleaning of an FFB.

DETAILED DESCRIPTION OF THE INVENTION

As used in this application, singular words should be read as plural and vice versa unless the context clearly and unmistakably states otherwise. For example, the term "a fruit" also includes a plurality of fruits.

Detached Fruits

A detached fruit is defined as a fruit that is intentionally detached from a harvested bunch. The process of detaching fruits is a planned activity. Detached fruits can be induced or natural. Induced detachment includes any methods actively performed on the fresh fruit bunch (FFB) to detach fruits, for example cutting, slicing, chopping, ethylene treatment, shaking, using physical force or heating. Examples of induced detached fruits are FFBs being given heat treatments such as steaming so that fruits detach from the spikelet. Natural detachment are fruits that fall off the FFB without any external intervention. Examples of naturally detached fruits include FFBs left in the open in the plantation with nets underneath to capture detach fruits that fall off naturally over time.

A fresh fruit bunch cluster is a subset of an FFB. FFB clusters can comprise for example a stalk with several attached spikelets, FFB split into two halves or an FFB chopped into ten pieces with these pieces still connected to each other by fibres. Mechanically removed FFB clusters are FFB clusters which are removed with the use of a machinery. An example would be using a chainsaw to tear the FFB into six smaller pieces. A spikelet is defined as a small spike which holds the inner, middle and outer fruits. Mechanically removed spikelets are obtained with the use of machinery to cut, saw, tear, slice or remove spikelets from its stalk. This action is done with minimal to no damage to the oil palm fruits. An example of mechanically removed spikelets is using a reciprocating blade to cut spikelets off from the FFB at the point where the inner fruits start growing. Spikelets can also be removed manually with the use of a sharp instrument such as a chisel to chip the spikelet off from the stalk of the FFB.

A loose fruit is any fruit that is collected prior to intentional detachment. For example, loose fruits can be collected before or during harvesting, transportation and other activities right up to the point before the fruits are detached intentionally. Examples of loose fruits include fruits that drop on the ground before harvesting the FFB or fruits that fall off the FFB in the mill while awaiting sterilization. Table 1 gives a brief overview of differences between detached and loose fruits.

For this process, detached and loose fruits can be processed together in any combination. For example, one embodiment uses only detached fruits. Another embodiment uses only loose fruits. Another embodiment processes no more than 70% detached fruits with the remainder made up by loose fruits. For example, one embodiment uses 70% detached fruits and 30% loose fruits. Yet another embodiment uses no more than 80% detached fruits and 20% loose fruits.

Table 1 - Detached and loose fruits differences

Impurity - Impurity is defined as non-oil bearing items that are not components of FFB. These impurities normally accrue from the start of a harvesting operation right up to the point before processing. Impurities are represented by the shaded region of Circle B as shown in Figure 7.

Impurity Weight - Total weight of all impurities.

Components of FFB - Organic parts of an FFB which are oil bearing (wanted) and non- oil bearing(unwanted). Examples of non-oil bearing components are cut stalk, calyx leaves, empty spikelets and undeveloped fruits. Non-oil bearing components of FFB are excluded from the impurity definition and subsequently the impurity percentage calculation.

Clean Fruits - Oil bearing fruits alone with nothing else. Clean fruits have no impurities.

Clean Fruits Weight - Weight of oil bearing fruits alone (clean fruits) without any non- fruit weight such as water adhering to its surface. Impurity Weight x 100

Impurity Percentage =

Clean Fruits Weight

Substantially Clean Oil Palm Fruits - Clean oil bearing fruits with an impurity percentage of 0%, or less than or equal to 0.01%, 0.1%, 0.5%, 1%, 3%, 5%, 7%, or 10%. Substantially Clean Oil Palm Fruits are also abbreviated as "substantially clean fruits". The term "substantially clean fruits" also includes clean fruits.

Table 2 - Definitions related to substantially clean fruits

The starting point for this disclosed process uses substantially clean fruits. The definitions are shown in table 2. The goal is to process substantially clean fruits with as little impurities as possible. Adding foreign items to substantially clean fruits does not circumvent infringement. Any items added to substantially clean fruits are deemed wanted items and are excluded from calculations.

According to Figure 2, substantially clean fruits are fruits that are collected with a method to capture clean fruits and/or fruits that have undergone a cleaning process to remove impurities. The process of detaching fruits from the FFB may be performed by any of a variety of methods known to those skilled in the art, or developed in the future. Methods of detaching fruits by cooking include using the existing conventional sterilization and threshing process. Methods for detachment and cleaning of substantially uncooked detached fruits are disclosed in co-pending Malaysian patent application PI 2016700359. One embodiment described therein uses ethylene.

If there are methods to capture clean fruits, the cleaning step can be skipped. Capturing clean fruits is defined as a process of capturing as clean a fruit as possible. For example, a method of capturing clean fruits is by individually picking up loose fruits off the ground by hand and putting it in a suitable receptacle. Impurities are dislodged during the picking process. The loose fruits in the container are substantially clean because the loose fruits collectively have low impurities. Another example would be setting up mesh nets underneath harvested FFBs to collect detached fruits that fall off naturally. This mesh captures clean fruits but allows impurities to fall through.

Fruits that have not been collected with a method to capture clean fruits are subjected to at least one cleaning step. As will be apparent with one skilled in the art, there are various methods of cleaning, either known in the art or developed in the future which can be used towards the goal of obtaining substantially clean fruits. For example, in the conventional process, we will clean detached fruits after threshing. Detached fruits from the sterilizer are dried with hot air to reduce moisture. Then they are put through a meshed rotating drum two or more times to separate out impurities. Sand, stone and dirt will be removed. Alternatively, fruits collected from the conventional process can be cleaned manually by hand with a cloth or brush until they are substantially clean.

Cleaning with air uses air to blow or suck impurities such that they are dislodged from the fruits. One embodiment uses a blower machine to blow away dirt from a meshed vessel that agitates the fruits. Dirt and other substances being lighter than the fruits will be blown or sieved through the prescribed mesh. Cleaning with water uses water as a medium to wash, rinse, soak or spray fruits to remove impurities. An embodiment uses a machine to soak and wash fruits in water. It is recommended that chlorine-free water is used.

A typical example of a cleaning and detachment process to illustrate the concept of substantially clean fruits and clean fruits is as shown in Figure 8. An FFB (1) is harvested from the plantation. Impurities are accrued (2) from the start of harvesting right up to the point of detachment. Some impurities (13) can be trapped within the FFB or stuck on its surface. When the fruits are detached (3) from the FFB, some impurities (4) will be removed during this detachment process (3). The detached fruits (5) are then cleaned (6) to remove more impurities (7) to obtain substantially clean fruits (8). Substantially clean fruits (8) is the starting point for this new process and can be processed to extract palm oil. Additionally, more cleaning (9) can be done to remove the remaining impurities (10) to obtain clean fruits (11) which can also be processed to extract palm oil. As this is an example, it is possible that the detachment step (3) does not remove any unwanted items (4). The detachment step (3) may also remove more impurities than the cleaning step (7 or 10).

Substantially clean fruits can be cooked or uncooked. For uncooked fruits, an optional step includes deactivating the enzymes responsible for the build-up of free fatty acid (FFA). (Here forth referred to as "FFA enzymes") Cooked fruits already have their FFA enzymes deactivated. The enzyme deactivation process should be done as soon as possible to limit the degradation of the oil quality. This optional step can be skipped if there are only minimal damaged fruits or if there are good handling of fruits. To deactivate the enzymes responsible for FFA formation, the FFB and/or fruit are heated to a temperature of at least 55°C. Just enough heat is applied to deactivate the enzymes but not cook the fruits. The process of FFA enzyme deactivation yields uncooked fruits. One embodiment administers dry heat using microwaves to heat the FFB to above 55°C but not cook them. Another alternative embodiment uses wet heat on fruits by steaming for about 5 minutes. Yet another embodiment uses an oven to heat the fruit's temperature to 60°C. Once the fruit's temperature reaches 60°C, heating is immediately halted. Yet another embodiment uses hot water to clean fruits and deactivate FFA enzymes simultaneously. Another embodiment uses hot air to clean and deactivate FFA enzymes. Sound waves can also be used to transfer heat to the FFB with ultrasonic horns and thermoacoustic heat engines.

The term substantially uncooked fruits also include uncooked fruits. Substantially uncooked fruits are fruits that are mostly uncooked. Slight cooking can happen for example if fruits are heated longer than required while deactivating FFA enzymes, but these fruits are still mostly uncooked. Substantially uncooked fruits are different to fruits that have gone through the conventional process or the continuous sterilization, which cooks fruits. The conventional and the continuous sterilization process heats up the fruits to 100°C or more with steam to detach and cook the fruits.

Substantially uncooked fruits cannot be properly digested. The mesocarp will not substantially detach from the nut during the digestion process. Substantially uncooked fruits need an additional cooking to soften the mesocarp for detachment from the nut. Substantially uncooked fruits are preferred for this disclosed process and can be obtained from detached and/or loose fruits.

An Example To Determine Substantially Clean Fruits

Four FFBs weighing 105.1kg in total are left in a shaded area outside in the open to detach naturally. The detached fruits are collected and washed with water to remove as much impurities as possible. The washed fruits are put into a first container. The washed fruits are still wet and need to be dried because clean fruits weight does not have water adhering to its surface. The fruits are dried by evaporation with the aid of a non-heated air blower. Once dried, the first container with fruits, impurities and components of FFB are weighed. This first container can be used as milling inputs for the palm oil extraction process. For the purposes of illustration, individual components are removed to explain the concept of substantially clean fruits.

From the first container, fruits are individually removed by hand and put into a second container. Care is taken to ensure any impurities and components of FFB stuck to the fruits are dislodged back into the first container. Next, components of FFB are individually removed to a third container. The first container (contains only impurities), second container (contains only clean fruits) and third container (contains only components of FFB) are individually weighed. For this example, (after removing respective container weights), we get the net weight of clean fruits as 65.22kg, net weight of components of FFB as 2.47kg and net weight of impurities as 1.93kg. The weight of components of FFB are excluded from impurity calculations. The impurity percentage for this example is:

Impurity Percentage = (1.93kg x 100) / 65.22kg = 2.96%.

At 2.96%, these fruits fall into the definition of being substantially clean.

Another Example To Determine Substantially Clean Fruits

For sample A, four FFBs weighing a total of 86.6kg have their fruits detached with ethylene over the course of 3 days. These detached fruits are uncooked. The detached fruits are cleaned with air to remove impurities. Then, the fruits are put into a first container.

For sample B, three FFBs weighing a total of 73.1 kg have their fruits detached by conventional sterilization. These cooked fruits are cleaned with air and put into a second container.

For sample, C 55kg of loose fruits are collected from the FFB hopper area of a plantation. These loose fruits are cleaned with water and then with air to dislodge impurities. They are then left to dry before being put into a third container.

Sample A, B and C have each of their individual components separated, measured and recorded as shown in Table 3.

Water On Fruit Surface 0.0 0.0 0.0

Miscellaneous Impurity 0.6 0.9 0.2

Table 3 - Individual component weight of samples A, B and C

Table 4 - Impurity weight for samples A, B and C

Table 5 - Impurity percentage calculation for samples A, B and C

This process performs at least the following steps on substantially clean oil palm fruits:

• Softening

• Digesting

• Separating

Oil can be extracted from substantially clean fruits in at least three steps. Most conventional mills cannot process palm oil without clarification, screening, de-sanding, de-stoning, purifying and other steps. These steps are more or less mandatory for conventional mills. However, for this disclosed process, these steps are optional and are merely alternatives to the various processing possibilities opened up by this disclosure. Adding water to this new process is also optional. The cleaner the fruit, the more steps can be skipped. This disclosed process does not require as much machinery as required by the conventional process. Having less machinery will reduce processing, labour and maintenance costs. Softening

The purpose of the softening step is to soften the mesocarp. The fruits should be softened such that the mesocarp can be easily detached from the nut and can be mashed up in the digesting step. Softening can be achieved by various methods such as boiling, friction, vibration, energy waves, steaming, hot air, sous-vide, chemical reactions and so on. This disclosed process uses at least one softening step. One embodiment uses non- pressurized steam to soften the fruits at room pressure for about 1 hour. Unlike conventional sterilization, cooking pressure is not critical. Alternative embodiments can use irradiation such as microwaves. An embodiment uses an 800 watt, 2450 MHz microwave to heat up the fruit for 3 minutes. Sound waves can also transfer energy for heating the fruits. Yet another embodiment uses hot air to heat up the fruits. Pressurized steam can be used for a faster cooking time. For example, under pressurized steam of about 3 bars, uncooked fruits can be cooked in under 30 minutes.

For cooked detached fruits, for example such as those obtained by the continuous sterilization process, may only need to be subjected to a mild softening process. The longer the fruits have been cooked, or the greater the exposure to steam, the less additional softening required. For example, in one embodiment, cooked fruits after continuous sterilization are subjected to further steaming for about 30 minutes.

Alternative machinery from other industries such as the culinary industry can be used for softening. Some examples are an air fryer and a sous-vide machine. Air frying cooks by circulating heated air around the food at fast speeds. Sous-vide is a method of cooking vacuum-sealed food slowly at a low (less than 100°C) and consistent temperature in a liquid bath. Induction heating is the process of heating an electrically conducting object (usually a metal) by electromagnetic induction, through heat generated in the object by eddy currents.

Digesting

The digesting step ruptures oil-bearing cells in the fruits to release palm oil. This can be achieved through friction, shredding, stirring, slicing or physical force. Physical force is any bodily force such as push, pull, compression or displacement. As a guide, a visual inspection can be performed to check that there are minimal to no fibres adhering to the palm nuts. The digested fruits are also called a digested mash. A typical digesting machine can be any machinery that uses force, physical motion, waves, compression, pulverizing, crushing or friction to digest the fruit. This disclosed process uses at least one digesting step. One embodiment uses a food mixer that has rotating arms to digest the softened fruits into digested mash for 15 minutes. Additionally, some machines also isolate the mesocarp (fibres) from the palm nut. A de-pulper is a generic term to refer to any machine that isolates mesocarp and palm nuts. There are many existing machinery for this purpose such as those used to de-pulp mangoes, tomatoes, coffee and plums. Modified pitting machines for olives, cherries, dates and avocadoes can also be used. Machines that grind, shred or utilize pressurized air or water can also be used. Depending on the machinery, some de-pulpers can isolate and completely digest mesocarp simultaneously while others do partial digesting and need another digesting step. One embodiment is a cylindrical de-pulper machine with curved rotating arms that beat the pulp and compresses the mesocarp through holes or gaps big enough to let the mesocarp through but retains the nuts. Another embodiment uses a two drum de-pulper to digest, isolate the fibres and separately polish the nut to further isolate extra fibres.

Separating

The purpose of the separating step is to separate palm oil from the solid component of the digested fruits. At least one separating step is needed to extract palm oil. With a proper setup, one step is enough to separate high quality palm oil from the digested fruits (digested mash). A one separating step embodiment is a rotary-vacuum drum filter where liquids are sucked from the digested mash through a filter media while solids are retained by the filter media. Yet another embodiment uses a filter press to separate liquids and solids from the digested mash using a slurry pump. An inventive improvement would be the use of a centrifuge such as a basket centrifuge to separate oil from the digested mash (fibre and nuts) in one step. The separating step can use other types of centrifuging such as a decanter or a peeler centrifuge.

The separating step also includes separating palm oil from fibres after nuts have been isolated. An embodiment uses a conventional screw press to separate palm oil from fibres obtained from substantially clean fruits with less than 1% impurity percentage. Cleaner fruits can use finer filters with smaller pores to allow palm oil through, in the separation process. Referring to figure 3, an embodiment using a depulper isolates fibres after the softening step. The oil fibres are then subjected to a peeler centrifuge to remove palm oil. The separating step also includes separating a palm oil mixture from solid components. Palm oil can be in a liquid mixture (e.g. dissolved in solvent like heptane) or a supercritical mixture, (e.g. dissolved in supercritical carbon dioxide) An embodiment separating a palm oil mixture is using hexane to dissolve palm oil from fibres. After dissolving palm oil, the liquid mixture of hexane and palm oil is separated using a screw press.

Additional Separating Steps

Optionally, digested mash or fibres that have gone through a separating step to remove palm oil can be subjected to further oil extraction with one or more additional separation steps to extract additional oil. An embodiment performs a separating step by screw pressing a digested mash to extract oil. After isolating nuts from the digested mash, the fibres go through another separating step by screw pressing again, to extract additional oil. Another embodiment separates palm oil from fibres (after nut isolation) using a decanter, then a tubular centrifuge before separating additional oil using a screw press for the third time.

Successive separating steps can be performed if coarse solid components are not fully removed. For example, substantially clean fruits with an impurity percentage of about 5% may require two or more separating steps. After the first separating step of oil extraction by screw pressing, the palm oil is subjected to bag or membrane filtering in another separating step. This example does not require the use of a vibrating screen because the oil is clean. In yet another separating step embodiment, oil is filtered three times in succession through bag filtering. Oil is put through a bag filter, collected and filtered again two more times using the same bag filter.

Addition of Hot Water and Clarification

The addition of hot water is an optional step for this process. By skipping the addition of hot water, we generate less POME. Clarification is the step to separate the underflow into oil and sludge. The clarification step is optional for this disclosed process because the palm oil obtained from this process has little to no sludge.

Purifying

The purpose of the purifying step is to remove fine impurities and some moisture from the oil. Unlike the conventional process, the purification step for this disclosed process is optional and can be skipped. One embodiment uses an inclined plate purifier just like the conventional process to separate impurities and water from an embodiment which has had water added to reduce its viscosity. Another embodiment uses a vacuum dryer to reduce the moisture content of the separated oil. The purifying step can use the methods described successively or in any combination. For example, another embodiment uses an inclined plate purifier before the oil is vacuum dried for moisture removal.

Additional Steps to the Process

Additional steps may be added to the disclosed steps above, for example, having a cleaning step between the softening and digesting step, having a distilling step to remove solvents, having a step to add enzymes during the digesting step or having an extra step to add solvent before the separating step. These listed additional steps are optional in this disclosed process.

Enzymes such as a cellulase, an amylase, a mannanase, a glucanase a pectinase, a protease can be added to increase the yields of the separating step by breaking down the cellular walls of the oil bearing cells. Enzymes can be added at any stage before, during or after the softening, digesting or separating step. An embodiment adds a blend of blend of pectinase, beta-glucanases, xylanases, cellulases and alpha-amylases enzyme during the digesting step where the softened fruits is digested with a conventional digested at a temperature of 70°C for 30 minutes. Then, the digested mash with enzymes are left for 2 hours at a controlled temperature of 65°C before it is screw pressed in the separating step.

Solvents such as hexane, heptane, cyclohexane, petroleum ether, dichloromethane or any suitable chemical for dissolving can be used to extract palm oil. Solvents also include subcritical or supercritical fluids such as carbon dioxide, water, methane, ethane, ethylene and so on. Solvent can be added at any stage during or after the softening step. An embodiment includes adding dichloromethane after the digesting step, then having a separating step of filtering the mixture of crude palm oil and solvent and then an additional step of distilling to extract palm oil.

Repeated Steps

To achieve their purpose, each of the softening, digesting and separating steps can optionally be repeated in succession, potentially using different methods when repeated. For example, in one embodiment, softened fruits are digested twice - first in a food mixer and then again in a conventional oil palm digester. Another embodiment recycles digested mash through the same de-pulper a second time to ensure cleaner isolation of fibres and nuts. Another embodiment performs two successive but different softening steps by steaming the fruits before heating them again using hot air. A repeated separating step embodiment subjects digested mash to decanter centrifuging before having another separating step using a rotary drum filter. The process of repeating of these individual steps in the current invention is optional.

Combining Steps

Optionally, the steps of softening, digesting, separating, palm nut isolation, cracking, kernel extraction and so on can be merged in any combination as there exist a diversity of machinery and methods for these purposes. One skilled in the art can combine and adapt the principles discussed to suit the situation and processing needs as required. For example, a stirrer can be mounted on a heating device to digest the fruits while it is being heated. An embodiment of this would be an induction cooker with a detachable or retractable mounted stirrer. Another embodiment uses an ultrasonic horn press with a frequency of about 20 kHz to soften and digest the fruits simultaneously. A de-pulper can also digest and isolate palm nuts simultaneously. Yet another embodiment combines a digester with a hydraulic vertical press.

Low Temperature Extraction

Palm oil processing is normally done in a heated environment above 90°C to get a higher oil extraction. A high temperature is needed because digested mash from the conventional process contains sludge, water and impurities. Low temperature extraction is an extraction process where lower than conventional milling temperatures are used and this step is optional. The disclosed process does not need such a high temperature because its digested mash is mostly palm oil with very little impurities. If any heating is needed, it will be minimal. With a proper setup, additional steaming or heating will not be required. This can be done for instance, by accelerating the process after softening, by combining steps or having a short digesting step. An embodiment uses a food mixer that digests the palm fruits for only 10 to 15 minutes before the separating step. The digested mash's temperature is still above 40°C when oil is being separated so no additional heating is required. Low temperature extraction is ideal for enzymes or catalysts. An optimum temperature can be selected where the catalyst or enzyme's catalytic activity is at its greatest. The use of sous-vide also permits the softening step to be performed at low temperature extraction with great precision. An embodiment uses a sous-vide machine to heat fruits with enzymes at a precise temperature of 45.6°C for 3 hours to soften the fruits.

Food-Safe Equipment

An optional and novel embodiment includes using food-safe equipment in the steps of softening, digesting and/or separating. For example, we can use a stainless-steel screw press for the separating step. Food-safe equipment, which are constructed using food-safe materials or with hygienic design, allows compliance with various food-safety standards and schemes. Some examples of food-safe materials include stainless steel, plastic, aluminium, silver, ceramic carbon and tungsten carbide. As there are many other types of materials currently known and hereafter developed, this list of food-safe materials is not exhaustive. Embodiments constructed with hygienic design ensure that non-food-safe oil, machine lubricant or other contaminants do no come into contact with the processed fruits directly or indirectly during the course of its operation. Where there is a possibility of contamination happening, the equipment design has measures to prevent or reduce the incidence of this occurring. Alternatively, food-safe lubricants can be used.

Food-Safe Virgin Palm Oil

This new process produces virgin palm oil. However, the users have the option to produce food-safe virgin palm oil with the use of food-safe equipment and/or following food-safety standards. Virgin oils are obtained, without altering the nature of the oil, by mechanical procedures (e.g. expelling or pressing) and the application of heat only. They may have been purified by washing with water, settling, filtering and centrifuging only. Virgin palm oil is superior to crude palm oil (CPO). Virgin palm oil can be used in place of crude palm oil in refining to produce higher quality outputs. An optional embodiment extracts palm oil using food-safe standards and procedures and can be certified food-safe by HACCP, ISO 22000 or any internationally recognized food-safety program.

Preliminary tests have been conducted on an embodiment. This embodiment uses only outer fruits of an FFB without deactivating FFA enzymes. Extracted oil are lab tested and the oil obtained from the outer fruits have a DOBI of 3.785 and an FFA of 1.915% as shown in table 6.

Outer Fruits 3.785 1.195% 616 ppm

Table 6 - Lab results for food-safe virgin palm oil

Deterioration of Bleachability Index (DOBI)

Table 7 - Palm oil quality categorized by DOBI

As seen in Table 6, the palm oil obtained from the outer fruits using the process as disclosed in this embodiment has a DOBI which is higher than 3.24 and having excellent grade.

Palm Nut and Fibre Isolation

Optionally, mesocarp (fibres) and palm nuts can be isolated for further processing to extract palm kernel from palm nuts and additional oil from fibres. Palm nuts may be isolated in any subsequent steps after the softening step from softened or digested fruits. In an embodiment, oily fibres are forced through a prescribed screen setting leaving the nuts behind for polishing to remove remnant oily fibres. Referring to Figure 4, the remaining fibres and nuts after the palm oil separating step are hereinafter called "clean press cake". Another embodiment for palm nut isolation uses a cake breaker to agitate the clean press cake and a winnower to isolate the lighter fibres from the palm nuts via a stream of air. Another embodiment uses a shell and kernel separator machine which removes the heavier nuts from the clean press cake.

Palm Oil and Palm Kernel Oil Mixture Optionally, the digested mash without any palm nut and fibre isolation can still be collectively screw pressed to get a mixture of palm oil and palm kernel. This separated palm oil has a small mixture of palm kernel oil because palm kernels are pressed during this separating step.

Kernel Extraction

This disclosed process produces clean kernels that do not need de-stoning. Referring to Figure 4, palm nuts that are separated from fruits in any stage after the softening step are subjected to drying before they are cracked. After cracking, the shells and kernels are separated. The extracted kernels are dried to reduce the moisture level to comply with the Malaysian palm kernel specification which allows up to 7% of moisture. One embodiment uses a ripple mill to crack the palm nuts after the drying process. Another embodiment uses a nut cracker. In one embodiment, a winnower is used to extract shells from the kernels. Another embodiment uses a modified walnut shelling separator machine to achieve this purpose. Hydrocyclone, clay bath or salt water can also be used. For the kernel drying step, an embodiment uses hot air to dry the extracted kernels for about 12 hours.

Mobile Unit

Processing substantially clean oil palm fruits allows usage of simpler and smaller machinery. The disclosed process provides the user the option to process oil palm fruits on a mobile unit. A mobile unit is defined as a movable establishment with equipment or materials necessary for a particular purpose. As will be apparent to one skilled in the art, the mobile unit can include for example a lorry (truck), a van, a detachable trailer, a shipping container, a box car, a cart, a movable platform or even attachments with wheels that affixes to palm oil processing equipment. Mobility can also be built into the palm oil equipment either permanently or semi-permanently. One embodiment is a modified screw press machine adapted with wheels and towed on roads. This mobility is different from wheels on some big and heavy machinery which are meant for temporary ease of deployment and relocation only. These wheels are not suitable for continuous or longdistance travel. Furthermore, the machinery generally requires a lengthy process of assembly at the venue before it can be used. Mobile units are easy to transport and can be operational almost immediately depending on the equipment setup. In one embodiment, palm oil processing commences within 24 hours of arrival of the mobile unit at the desired location.

Mobile units can process all or a subset of the steps required for this disclosed process and are scalable. One embodiment houses a conventional digester for the digesting step only. Another embodiment comprising three lorries houses a pressure cooker for softening in the first lorry, a digester in the second and a filter press in the third. The mobile units can also house equipment for non-sequential steps. In another embodiment, one box car houses equipment for the softening and separating steps. Palm oil equipment can also be disassembled and split between separate mobile units and assembled at the desired location for processing. Related machinery that processes a single processing step can also be stored in different mobile units. Optionally, the mobile unit can have supplementary items such as one or more power sources, water supplies, oil silos and fruit storage containers. The mobile unit can also depend on the location or external sources for power, water and other needs. Workload can be split between the mobile unit and existing machinery at the location. One embodiment houses a shredding machine (de-pulper) with its own diesel power generator and has a leak-proof container to store virgin palm oil. Yet another embodiment stores palm kernel oil after palm kernel oil extraction. The mobile unit can be deployed anywhere. Ideally the location for deployment is one that minimizes the cost of FFB transportation or poses some significant strategic or economic importance. As mentioned above, co-pending Malaysian patent application PI 2016700359 discloses a method for detaching oil palm fruits which can be done at the plantation. An embodiment comprising a 20-foot shipping container that houses palm oil processing equipment for the softening, digesting and separating steps can visit the plantation to extract virgin palm oil.

Processing Capacity

The process as disclosed above is capable of processing at least 100 kg of oil palm fruits per hour and up to 7000 kg, or more, of oil palm fruits depending on the requirements.

The following are examples to illustrate this new process and to teach one skilled in the art the concepts and ramifications. These examples are not meant to limit the scope of the invention in any way.

Example 1

In a preferred embodiment, ripe FFBs have their enzymes deactivated by heating it in an enclosed room with a heater to 55°C for 30 minutes at the plantation. Then, oil palm fruits are detached by exposing the FFBs to a concentration of 250ppm ethylene in the same enclosed room for up to 3 days. The FFB is put through a thresher to detach fruits. The detached oil palm fruits are then cleaned in a whirlpool, circulated water bath.

Referring to Figure 6, the substantially uncooked and cleaned oil palm fruits are put in stainless-steel trays and steamed in a commercial food-safe steamer at atmospheric pressure for about 1 hour to soften the mesocarp. The steamed fruits are then digested in several 20-litre food-safe food mixers for about 15 minutes with a stirring speed of 80 revolutions per minute to mash up the mesocarp. After digesting, the oil is separated using a basket centrifuge. The remaining clean press cake is subjected to an agitator and fibres are isolated by winnowing. The isolated fibres are heated to 95°C with steam and a screw pressed to extract the remaining oil. If the extracted oil has a high moisture content, it is allowed to settle in a tank. Clean oil will be skimmed off. Dirt will be drained off from the bottom. The steam condensate from this process is treated for recycling as wash water. Nuts obtained from this process are dried in a silo at 70°C for about 12 hours. The dried nuts are then cracked with a ripple mill and the shells and kernels are separated using a winnowing machine. The kernels are dried using hot air for 10 hours to reduce the moisture level to 7%. This palm oil extraction process meets all the strict food-safety criteria and can be certified food-safe in compliance with HACCP.

Example 2

Detached fruits are cleaned by first rinsing them with water before cleaning them again with air. The air also blow-dries them simultaneously. Then the fruits are softened and digested using an ultrasonic horn press. The energy released from the ultrasonic horn heats the fruits to a temperature of about 80°C while vibrations simultaneously disrupts and beats it into a digested mash. For faster digesting, the fruits can optionally be pre- softened by steaming for about 15 minutes. The digested mash is then pressed with a stainless-steel screw press to extract oil. The oil is then filtered in the separating step using a vibrating screen with a fine mesh (125 mesh) to remove fine solids. No further clarification or separating steps are subsequently needed because the oil has minimal sludge.

Example 3

FFA enzymes are deactivated for detached fruits using hot air in a heated room for 30 minutes at a temperature of 55°C. Then, fruits are softened in a pressurized vessel with pressurized steam at 3 bars for about 15 minutes after a 2-minute de-aeration. After softening, the fruits are digested with a palm oil fruit pounding machine for 30 minutes. The fruit pounding machine pounds and crushes the digested mash to release oil but does not crack the nuts. Palm oil is separated from the digested mash using a filter press after it has been heated with steam up to 80°C. The digested mash is subjected to pressure and oil is collected by forcing it through a filter. The extracted oil is left to settle by gravity before being vacuum dried to remove moisture. Fibres are isolated from palm nuts by winnowing and are pressed for additional oil. The palm nuts are dried and cracked with a nut cracking machine. Finally, the kernels are recovered using a clay bath and dried with hot air for 16 hours.

Example 4

In a preferred embodiment, hot moist air at 95°C softens the substantially clean oil palm fruits for 90 minutes. Moist air is air that has high levels of humidity as created by a humidifier. After softening, the fruits are put through a rotating cylindrical shredder machine (de-pulper) which shreds the mesocarp from the nuts. The separated wet oily fibres are then digested in a low speed blending machine, which has rotating blunt arms to mix and blend the pulp at 40 revolutions per minute. After digesting, the oil is separated using a rotary vacuum drum which sucks out the oil from the fibres. The fibres are heated to 85°C and screw pressed for additional oil. The nuts are dried and cracked using a ripple mill. The shells are separated using a winnower and further separated again with a hydrocyclone.

Example 5

In another embodiment, the oil palm fruits are microwaved in a 1000W, 2500Hz microwave for 4 minutes. The microwaved fruits are then digested in a steam-heated cylindrical vessel fitted with a central rotating shaft carrying a number of beater arms. After digesting, the oil is separated from the digested mash using a tubular centrifuge. The collected oil is bag-filtered before being vacuum dried. A high-pressured water gun isolates fibre from the clean press cake by forcing it through a mesh under high pressure. Supercritical carbon dioxide is used to extract oil and phytonutrients from the fibres at 80°C and a pressure of 30MPa. The extracted palm nuts are dried using hot air. Once dried, they are cracked using a nut cracker machine. A nut shell separator machine then separates shells and extract kernels. Example 6

One FFB is put through the conventional process of pressurized steaming at 3 bars for 1 hour. The fruits are cleaned manually by hand using a brush after threshing. The clean fruits are first softened in boiled water for 5 minutes and then softened again with an air fryer at 100°C for about 3 minutes. The softened fruits are digested with a cylindrical machine with impeller arms operated by a motor for 20 minutes. Then they are sent to a grinding machine(de-pulper) to isolate palm nuts and fibres. Then the fibres are screw pressed to extract oil in a heated environment of 76°C.

Example 7

In a preferred embodiment, detached fruits are cleaned with an air blower machine which removes impurities as fruits are rolled around in a rotating cylinder of the machine while being blown by air. Then the fruits are cleaned with a water bath to remove soluble impurities. Referring to Figure 5, fruits are vacuum sealed in a food-safe plastic pouch and put in a sous-vide machine. The sous-vide machine cooks the fruit in a water bath with a controlled temperature of 60°C for about 70 minutes. Then, they are digested in a commercial food stirrer machine which stirs vigorously for 15 minutes before being sent to a grinding machine for de-pulping. The grinding machine has two stone grinders that rotate in opposite direction to isolate fibres from the nuts using friction. The fibres are then screw pressed to extract oil. The palm nuts are cracked with a palm nut shelling and cracking machine. The machine cracks the nuts and separates shell simultaneously. The extracted kernels are then dried with hot air at 80°C for 12 hours. A 10-tonne lorry houses all these machines and has its own power and water source.

Example 8

Loose and detached oil palm fruits are cleaned with air before being put in a hot water solution of 60°C for 10 minutes. The clean oil palm fruits are put in an oven and heated up to 70°C for about 24 hours. Then they are digested for 1 hour in a conventional palm oil digester which is cylindrical with rotating beater arms to digest the oil palm fruits. The digested mash is then hydraulic pressed without nut and fibre isolation to get palm oil. This palm oil has a mixture of palm kernel oil.

Example 9

FFB clusters are obtained by cutting an FFB with a chainsaw to many pieces. These clusters are washed with steam (hot water) to partially clean the clusters and deactivate FFA enzymes. After being left to detach naturally over 7 days, the detached fruits are collected and cleaned with air. The substantially clean fruits are softened with steam for 45 minutes before being softened again with hot air for 20 minutes. Then, pectinase enzymes are added to the softened fruits and left to sit for 45 minutes before they are digested in a steam-heated vessel which has attached stirring arms that rotate in a circular motion for 20 minutes at a temperature of about 80°C. The digested mash is centrifuged with a three-phase decanter. The extracted oil is separated in another separating step by pumping it through a membrane filter. The palm nuts are removed manually by hand. The isolated fibres are heated to 70°C and then screw pressed to recover additional oil. All these machines are housed in a 20-foot container towed by a lorry. This mobile unit goes to various plantations to process oil palm fruits.

Example 10

In a preferred embodiment, referring to Figure 3, clean fruits are softened by steaming at atmospheric pressure for about 40 minutes. Then the fruits are put through a 2 chamber de-pulper. This de-pulper simultaneously digests the fruits and isolates the nuts and fibres. The de-pulper's first chamber has slight curve rotating arms to beat the mesocarp into a pulp and force the fibres through a small mesh, leaving the nuts to go through to the second chamber. In the second chamber, a rotating brush cleans and remove remnant fibres from the nuts. The isolated fibres digested with a digester for 20 minutes. The fibres then are heated up to 80°C and pressed with a stainless-steel screw press to extract oil. The isolated palm nuts are dried in an oven at 70°C for 12 hours. A nut cracking machine which has two cylindrical rollers and spikes crushes and breaks up the nuts. The lighter shells are collected by winnowing. The extracted kernels are then dried in an oven at 70°C for 16 hours.

Example 11

Fruits from five FFBs are detached using machines. The FFBs are individually cut with a chainsaw to divide each FFB into several FFB clusters. These clusters are left to detach naturally in a box after FFA enzyme deactivation using hot air. These induced detached fruits are collected by putting it through a thresher. Subsequently, the detached fruits are cleaned in an air jet cleaning machine. The air jet cleaning machine has multiple nozzles to blow away impurities from the fruits while they are subjected to a rotating action inside the machine. The resultant substantially clean fruits are then softened with steam for 45 minutes inside a steamer. Once softened, they are digested in a pan mixer machine. A pan mixer machine is a mixer with an opening at its top, usually a pan or drum within which mixing attachments revolve about the vertical or horizontal axis. The mixing attachments of the pan mixer are customized for oil palm digestion. Once digested, the digested mash is screw pressed to extract palm oil. Fibres are isolated with a winnower. Hexane is added to these fibres and left for 1 hour. The hexane is separated from the solid components using a filter press. The liquid component is then heated to separate hexane from palm oil. Palm nuts are cracked with a nut cracker machine. Isolated palm nuts are fed from the hopper into a rotating spinner from which they are thrown by centrifugal force to the outer casing, causing the nuts to break, before being discharged. Kernels are extracted from remaining loose shells in a salt water solution.

Example 12

In a preferred embodiment, an electric knife is used to cut the FFB into spikelets, which are then put on a meshed stand with a metal net underneath to collect any detached fruits. The spikelets are heated in a room to 60°C for 40 minutes to deactivate FFA enzymes. The same room is pumped with a 0.5% concentration of ethylene and maintained at an elevated temperature of 40°C for three days. Once collected, detached fruits are washed with water to get substantially clean fruits. These fruits are put in a stainless-steel industrial cooker which has a built-in mixer for about 1 hour. The induction cooker softens the fruits while the mixer simultaneously digests them at a stirring speed of 30 revolutions per minute. Then, the digested mash with oily fibres are put through a two-chamber pulping machine (de-pulper). The first chamber has a rotating blunt blade that pushes the mesocarp through a screen. The second chamber repeats the same process again but with a finer screen. The isolated fibres are heated to 70°C and screw pressed to separate oil from the fibres. Thereafter, the fibres are subjected to another separating step using subcritical fluid extraction of carbon dioxide with the parameters of 80°C and 100 bar pressure.

Example 13

In a preferred embodiment, an FFB is separated into spikelets with the use of a machine. This is done using a vibrating saw to cut off the spikelets as close as possible to the FFB stalk without damaging the fruits. Loose fruits are collected and cleaned with hot air for FFA enzyme deactivation. The mechanically removed spikelets are then heated to 55°C with a heater for 30 minutes in an enclosed room in a palm oil estate. Ethylene is then pumped into the room to about 500ppm and these spikelets are left to detach over 2 days. Oil palm fruits detached from the spikelets and loose fruits are collected and put through a food-safe fruit cleaning and washing machine. This cleaning and washing machine is made of stainless-steel and uses an exhaust fan to suck away impurities and other lightweight items. Then the cleaning machine washing drops the oil palm fruits in an aerated hopper which washes the fruits in a bubbly water bath before giving the fruits a final water shower to rinse the fruits. These clean fruits are then put in food-safe stainless-steel trays and steamed in an industrial steamer for about 1 hour until the mesocarp is soft. Then the softened fruits are put through a food-safe stainless-steel depulper which digests and isolates the palm nut from the mesocarp. The isolated fibres are transferred into an industrial sanitary food mixer and digested for about 15 minutes. The fibres do not require additional heating as it is still hot after the softening process. The digesting step is done at a low temperature extraction of 70°C or less. After digesting, the fibres are put through a food-safe 2-phase decanter which separates out palm oil. For extra recovery of oil, the fibres are heated up to 70°C and screw pressed in a stainless-steel screw press in another separation step. This whole process is conducted following food-safe procedures and standards and can be certified food-safe by relevant food safety governing bodies. Food- safe virgin palm oil is extracted from this embodiment. The fruit washing machine, industrial steamer, depulper, decanter, screw press and other equipment are house in a 20-foot shipping container. This container is towed by a lorry and goes from plantation to plantation to extract palm oil.

Example 14

In a preferred embodiment, loose fruits are collected before the detachment process, an FFB is separated into clusters with a circular saw. These FFB clusters together with detached fruits (that have fallen off due to the cutting process) and collected loose fruits are heated to 55°C in a heated container to deactivate FFA enzymes. The FFB clusters are left to detach naturally with ethylene. The detached and loose fruits are collectively washed three times with water that is chlorine-free. Dirt, soluble contaminants and other impurities are removed. Then, the substantially clean fruits vacuum sealed in a bag with an aqueous combination of protease, glucanase, xylanase and cellulase enyzmes. These fruits with enzymes are put in a sous-vide 65°C warm bath for 90 minutes to soften the fruits. After softening, the fruits are digested in an industrial mixer with rotating blades of lOOrpm for 20 minutes. The digested mash is heated up to 80°C to reduce viscosity and then screw pressed to extract palm oil. Fibres are isolated from the press cake with a winnower. The fibres are then heated and pressed for additional oil.

Example 15

Detached fruits were obtained from an FFB. The detached fruits were cleaned water by rinsing and soaking to produce clean fruits. The clean fruits were vacuum sealed in a food-safe plastic pouch and put in a sous-vide machine. The sous-vide machine cooked the clean fruit in a water bath at a precise temperature of 70.0°C for about 60 minutes. Then, the softened fruits were digested in a food-safe food stirrer for 15 minutes. After digesting, palm oil was extracted from the digested mash using a basket centrifuge. The extracted oil had no sludge. The oil was heated to 110°C and was left to settle by gravity. The oil was examined again but no sludge was found. The digesting and separating step were done in a low temperature extraction without any additional heating.

Example 16

Detached fruits were cleaned physically and were washed with water to produce clean fruits. These clean fruits were steamed with a food-safe steamer for 45 minutes. Then, the steamed fruits were digested using a stainless-steel food-mixer. The digested mash was pressed with a manual screw press. No vibrating screen were needed for the separated oil. In addition, the separated oil had no sludge. The separated oil was allowed to settle for 24 hours and the findings that no sludge were discharged by this novel process was confirmed. No additional heating were used for the digesting and separating steps.

A skilled reader will appreciate that the invention may be embodied in ways other than those specifically described herein without departing from the scope as defined by the following claims.