FIELD OF INVENTION

The present invention relates to an apparatus for rice bran stabilization. Particularly, to an apparatus for rice bran stabilization using ohmic heating.

BACKGROUND OF THE INVENTION

Rice bran is the outer hull or coating on rice grains which is often removed before the grain is processed for human consumption. The rice bran is an excellent source of nutrients and bioactive compounds including fat, dietary fiber, carbohydrate, antioxidants, vitamins and protein. The rice bran can be used to produce but not limited to cleansers, skin care products, fortified foods and functional foods.

However, raw rice bran (unstabilized rice bran) is not suitable for human consumption due to rapid rancidity of fat found in the rice bran by lipase enzyme. The rancidity which takes place immediately after milling process produces free fatty acids (FFA) and glycerol causing the rice bran unsuitable for human consumption. Thus, raw rice brans are usually used as animal feeds since animals are able to digest it.

There have been attempts in the art to stabilize raw rice bran by reducing the lipase activity within the rice bran to a lowest possible level while maintaining its nutritional value. Conventionally, heat stabilization apparatus is used to either reversibly inhibit or permanently denature the lipase enzyme that is responsible for the rancidity of fat in the rice bran.

One of the heat stabilization methods used to inactivate the lipase activity in rice bran is ohmic heating. Ohmic heating generates heat by passing electrical current through the rice bran which resists flow of electricity. However, the rice bran stabilized through conventional ohmic heating has a shelf life of approximately six months. Currently, there is a dearth of rice bran stabilization techniques through ohmic heating yielding stabilized rice bran which is stable and safe for human consumption beyond six months of storage at ambient conditions.

Having said the above, it is obvious that existing ohmic heating apparatus for rice bran stabilization are inept at extending the shelf life of the rice bran. As such, it would be advantageous to develop an apparatus for rice bran stabilization.

SUMMARY OF THE INVENTION

The present invention relates to an apparatus for rice bran stabilization, comprising: a pressurizable chamber and a control box. The pressurizable chamber includes an inner chamber for receiving and containing a rice bran mixture; and at least one electrode capable of being in electrical contact with the rice bran mixture on at least one end of the inner chamber and produce an electric field for modified ohmic heating of the rice bran mixture. The control box is electrically coupled to the pressurizable chamber for controlling variables including current, temperature, voltage or pressure conditions of the pressurizable chamber to facilitate rice bran stabilization.

Preferably, the pressurizable chamber comprises a safety valve for manually releasing pressure in the pressurizable chamber. Additionally, the pressurizable chamber comprises insulating boards for insulating electricity within the inner chamber.

Further, the pressurizable chamber comprises at least one sensor to measure pressure conditions of the inner chamber; and at least one thermocouple positioned in anyone one of a top, middle or bottom regions of the rice bran mixture to measure the temperature of the inner chamber during stabilization, wherein the sensor and the thermocouple are communicably coupled to the control box to provide sensed pressure and temperature conditions. Still further, the inner chamber is made from a material selected from the group consisting of polypropylene, high-density polyethylene, polyvinylidene fluoride, polytetrafluoroethylene, ceramic, glass or quartz.

Furthermore, the pressurizable chamber consists of two electrodes, wherein the electrodes are coaxially aligned and spaced apart by 9.4 cm to 41 .5 cm on two opposing ends of the inner chamber.

Preferably, a first electrode (138) has a thickness ranging between 15 mm to 30 mm and a second electrode has a thickness ranging between 2 mm to 6 mm.

Typically, the apparatus (100) comprises a compacting means to compact the rice bran mixture (200) in the inner chamber (126).

In accordance with this invention, the apparatus comprises an air compressor to pressurize the pressurizable chamber (110) between 103.4 kPa (15 Psi) to 482.6 kPa (70 Psi).

Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings constitute a part of this specification and include an exemplary or preferred embodiment of the invention, which may be embodied in various forms. It should be understood that the disclosed preferred embodiment is merely exemplary of the invention. Therefore, the figures disclosed herein is 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. Figure 1 shows a block diagram of the apparatus for rice bran stabilization according to the present invention.

Figure 2 shows a back perspective view of the pressure chamber, according to the present invention.

Figure 3 shows a back perspective view of the pressure chamber without a top cover, according to the present invention.

Figure 4 shows a front perspective view of the pressure chamber without a top cover, according to the present invention.

Figure 5 shows a front perspective view of the pressure chamber without a top cover and an inner chamber, according to the present invention.

Figure 6 shows a top perspective view of the pressure chamber without a top cover and an inner chamber, according to the present invention.

Figure 7 shows a front perspective view of the pressure chamber with rice bran filled in the inner chamber, according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Detailed description of preferred embodiment of the present invention is disclosed herein. It should be understood, however, that the embodiment is merely exemplary of the present 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 claim and for teaching one skilled in the art of the invention.

Referring to the accompanying drawings, Figures 1 to 7 show preferred embodiments of the present invention being an apparatus (100) for rice bran stabilization. The present invention relates to an apparatus (100) for rice bran stabilization wherein rice bran is stabilized through ohmic heating in a pressurized chamber (1 10). As the ohmic heating envisaged by the present invention is carried out under high temperature, high voltage and pressure conditions it is also referred to as modified ohmic heating. The stabilized rice bran is prepared from rice bran collected from first polishing step of rice grain milling process, second polishing step of rice grain milling process, third polishing step of rice grain milling process and mixtures therefrom, preferably first polishing step of rice grain milling process and wherein the rice bran is preferably stabilized within 4 hours after milling of the rice grain.

Further, the embodiments described herein can be used to stabilize bran of any cereal grains such as but not limited to rice, wheat, oat, barley, rye and millet. Hereinafter the teachings of the present invention will be explained using rice bran as a representative example of a bran that can be prepared using the apparatus described herein. For the purpose of the present invention and the accompanying claims, the term “stabilized rice bran” is used to refer to rice bran which has been treated soon after milling by modified ohmic heating that will substantially reduce the lipase activity.

The present invention discloses an apparatus for manufacturing stabilized rice bran. The apparatus stabilizes the rice bran to prevent it from being rancified after it’s milled, by applying high voltage for a certain period of time under high pressure conditions.

Figure 1 shows a block diagram of the apparatus (100) in accordance with the present invention. The apparatus (100) comprises a pressurizable chamber (110), a control box (150), and a monitor (160).

The pressurizable chamber (110) includes at least an inner chamber (126) for receiving and containing a rice bran mixture (200); and at least one electrode (138) capable of being in electrical contact with the rice bran mixture (200) on at least one end of the inner chamber (126) and produce an electric field for modified ohmic heating of the rice bran mixture (200). The control box (150) acts as controlling means to manipulate variables including current, temperature, voltage and/or pressure conditions of the pressurizable chamber (1 10) to facilitate rice bran stabilization. The control box (150) is communicably coupled to both the pressurizable chamber (110) and the monitor (160). The monitor (160) receives and displays sensor reading and operating parameters of the pressurizable chamber (1 10) and can facilitate in receiving and relaying a user’s input or instructions to the control box (150) for manually overriding current, temperature, voltage and/or pressure conditions of the pressurizable chamber (1 10). The monitor (160) can be a physical display or an interactive graphical user interface.

The control box (150) comprises an earth leakage circuit breaker, electromechanical switch, a processing unit such as Raspberry PI 3, a PT100 signal conditioner, an analog converter, relay modules, pneumatic valves, voltage transformer, contactor, current sensor, a variac and a communication system. The control box (150) also acts as a processing unit and functions to control the process conditions via variables including current, temperature, voltage and pressure during ohmic heating of the rice bran mixture. The variac in the control box (150) is for controlling the current during ohmic heating.

In addition, the control box (150) collects and relays the process parameters to a remote unit (not shown) via its communication system for data collection and process optimization. The communication system (not shown) of the control box (150) consists of wired and wireless interfaces used for communicating with the pressurizable chamber (110) to receive sensor data for temperature and pressure during rice bran stabilization process, process the data using the processing unit (not shown) and relay the processed sensor data to the monitor (160) and the remote unit.

The monitor (160) is connected to the control box (150) wherein it shows version of software being used by the processing unit, thermocouple temperature value, pressure value, current value, thermocouple trend line graph, process status, start/stop button, process time, holding time count up, pressure/current value (chart), settings and electrode voltage. The monitor (160) has a bi-directional communication with the communication system of the control box (150) to perform each of the aforementioned operations as well as receive an input via any of the conventional methods such as touch, keypad based or voice based from the user operating the apparatus (100) to relay to the control box (150) to adjust temperature, current and pressure variables during stabilization.

According to one aspect of the present invention, the operation of the apparatus (100) is explained hereinafter. The rice bran mixture is introduced in an inner chamber (126) within a pressurizable chamber (1 10) of the apparatus (100). The rice bran mixture comprises raw rice bran, an electrolyte solution and an electroconductive compound. The rice bran mixture further includes an additive. The raw rice bran is used in granule form, wherein the raw rice bran has a moisture content ranging between 6.0% to 10.0%, preferably 8.0% by weight of the raw rice bran. The process for preparation of the rice bran mixture for use in the apparatus (100) is disclosed in Malaysian patent application number PI 2020004688 filed on September 9 ^th , 2020, contents of which are hereby incorporated herein by reference in their entirety.

The inner chamber (126) is connected to two electrodes wherein each electrode (138) is configurable to make electrical contact with the rice bran mixture and produce an electric field for ohmic heating of the bran when very high voltage is applied to the electrodes. The power supply to the apparatus (100) is cut-off by the control box (150) on reaching a threshold temperature and pressure. The control box (150) then maintains temperature and pressure conditions for a predetermined period of time, preferably 10 seconds and then allows the rice bran mixture to cool down below 100°C while maintaining the threshold pressure to obtain rice bran which is stabilized and suitable for human consumption.

Figure 2 shows a back-perspective view of the apparatus (100) and Figure 3 shows a front perspective view of the apparatus (100). The pressure chamber (1 10) comprises of a top cover (122) wherein the top cover (122) can be opened through top handles (124). The top cover (122) is connected to a bottom enclosure via a plurality of nuts-and-bolts connection. The bottom enclosure comprises a stand (140) for keeping the apparatus (100) upright. Figure 3 shows a back-perspective view of the apparatus without a top cover (122) and Figure 4 shows a front perspective view of the apparatus (100) without a top cover. The pressure chamber comprises a silicon gasket (128), at least one thermocouple, a pressure sensor (134), an air inlet (132a), an air outlet (132b), at least one top electrode (138), an inner chamber (126), a pressure relief valve (136), a bottom electrode connector.

According to the invention, the apparatus (100) comprises a pressurizable chamber (1 10) which includes an inner chamber (126) for receiving a rice bran mixture for stabilization. The chamber (110) is made from any metal that conducts electricity and can withstand high pressure including but not limited to stainless steel, mild steel, carbon steel, galvanized steel, aluminium alloy, copper, bronze and brass. The chamber (110) is pressurized between 103.4 kPa (15 Psi) to 482.6 kPa (70 Psi), preferably 344.7 kPa (50 Psi) using an air compressor (not shown in the figures).

Figure 5 shows a front perspective view of the apparatus without a top cover and an inner chamber. Figure 6 shows a top perspective view of the apparatus without a top cover and an inner chamber.

The inner chamber (126) is made from any non-electrical conducting material that can withstand voltage of up to 1000 V AC and temperature of up to 170°C including but not limited to polypropylene (PP), high-density polyethylene (HDPE), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), ceramic, glass and quartz. The inner chamber (126) is enclosed by insulating boards. The insulating boards are made from an electrical insulating material, wherein the electrical insulating material is selected from the group consisting of Bakelite, High Density Poly Ethylene, Polyvinylidene fluoride and Polytetrafluoroethylene. Referring to figures 3 to 6, the pressurizable chamber (1 10) includes at least one first electrode (138) and at least one second electrode (not shown) for coming into contact with rice bran mixture for high voltage electric field-induced ohmic heating. The at least one first electrode (138) and at least one second electrode are connectable from the top and bottom of the inner chamber (126). The electrodes are made of any metal that conducts electricity and can withstand temperature of up to 170°C which includes but not limited to stainless steel, mild steel, carbon steel, galvanized steel, aluminium alloy, copper, bronze and brass. The at least one first electrode (138) has a thickness ranging between 15 mm to 30 mm and the at least one second electrode has a thickness ranging between 2 mm to 6 mm, wherein the electrodes are coaxially aligned to each other and spaced apart in range of 9.4 cm to 41 .5 cm.

The bottom electrode is connected to a connector (139) that comes into contact with rice bran. The surface of the first electrode (138) in contact with the top surface of rice bran mixture is applied with an electrolyte solution. The electrolyte solution is any edible electrolyte solution and wherein the electrolyte solution has a molarity ranging between 0.5 M to 2.0 M, preferably 1.2 M. Alternatively, the surface of the electrodes is polished to increase electrical contact of the electrodes when in contact with the rice bran mixture.

At least one sensor is provided in the inner chamber (126) to monitor the current, temperature, voltage and/or pressure conditions. According to the invention, a pressure sensor (134) is provided to monitor the pressure conditions in the pressurizable chamber (1 10). Three thermocouples (130a, 130b, 130c) are positioned in top, middle and bottom regions of the rice bran mixture respectively for measuring the temperature during stabilization. The safety valve (136) is to manually release the pressure in the chamber (1 10). The air inlet (132a) and air outlet (132b) are provided to channel air into and out of the chamber (110).

Preferably, the apparatus comprises compacting means to compact the rice bran to increase conductivity and to decrease volume of the rice bran being processed. The rice bran is compacted by 40% to 60% of its original volume. In a non-limiting example, the compacting means is a pressurized air cylinder. Alternatively, the compacting means is a piston or a moving arm.

Figure 7 shows a front perspective view of the apparatus with rice bran mixture (200) received in the inner chamber. The method of stabilizing rice bran using the apparatus (100) shall be explained as below.

In accordance with another aspect of the present invention, at least the control box (150) and/or the monitor (160) are embedded with the pressurizable chamber (1 10) to provide a single rice bran stabilization apparatus (100). Alternatively, the control box (150) and the monitor (160) are distinct units placed in proximity with the pressurizable chamber (1 10) or remotely located units (150, 160) either on a server or on cloud and co-operating with the pressurizable chamber (1 10) via a wired or wireless interface.

In accordance with yet another aspect of the present invention, the apparatus (100) for rice bran stabilization comprising a pressurizable chamber (1 10) including an inner chamber (126) for receiving and containing a rice bran mixture (200); and at least one electrode (138) capable of being in electrical contact with the rice bran mixture (200) on at least one end of the inner chamber (126), wherein the at least one electrode (138) produces an electric field for modified ohmic heating of the rice bran mixture (200) on application of voltage in a range between 240V to 415V to produce stabilized rice bran.

Basic Operation Guide of the apparatus (100) is explained hereinafter:

1 . Fill the rice bran mixture into the inner chamber

2. Place a top electrode into the inner chamber in contact with the rice bran mixture

3. Ensure the top electrode is attached to the electrode position and is not loose

4. Ensure the silicon gasket is clean wherein there is no foreign particle on it

5. Ensure an inner electrode wire is attached to its plate and is not loose

6. Close top cover and assemble and tighten all 20 nuts with spanner 7. Insert top, middle and bottom thermocouples carefully and securely

8. Check the monitor if: a. Top thermocouple and middle thermocouple has value b. Electrode Voltage is 240V or 415V c. Pressure and current is Zero d. Start button is Green.

9. Click “Start” button

10. Click start on confirmation pop up

1 1 . Machine started and green light on panel lights up

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises", "comprising", “including”, and “having” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups therefrom.

Reference signs:

100 apparatus

1 10 pressurizable chamber

122 Top Cover

124 Top Handles

126 Inner Chamber

128 Silcone Gasket

130a Top Thermocouple

130b Middle Thermocouple

130c Bottom Thermocouple

132a Air Inlet

132b Air Outlet

134 Pressure Sensor 136 Pressure Relief Valve I safety valve

138 Top Electrode

139 Bottom Electrode Connector

140 Stand 150 Control Box

160 Monitor

200 Rice Bran