Title of Invention

"An Improved Process for the Preparation of Processed Nuts"

Abstract The present invention relates to an improved process for the preparation of processed nuts. The present invention particularly relates to a process for infrared heating of nuts such as groundnut, pista and cashew kernel for facilitating the removal of testa from the kernel and for processing the nut economically.
Full Text The present invention relates to an improved process for the preparation of processed nuts. The present invention particularly relates to a process for infrared heating of nuts such as groundnut, pista and cashew kernel for facilitating the removal of testa from the kernel and for processing the nut economically.
Nuts are one of the important crops of India. The shelling of these nuts and removal of testa are the two major operations in nut processing. The shell of cashew nut is presently removed manually or with help of gadgets after roasting the whole nuts or steam treatment. The nuts are soaked in water before roasting, in order to increase moisture content up to 15-20%. The removal of testa (or peeling) is the most critical step in cashew processing. For this purpose the moisture level is brought down to about 4 -5% (on wet basis) by drying for 6-7 hrs in natural convective dryers called Bourma dryers. The Bourma dryer consists of a metal chamber indirectly heated by a masonry furnace below the flues, build around the metal box on two sides. The cashew kernels are spread on trays having wire mesh bottom and placed inside the metal chamber for drying. The design of these dryers being far from satisfactory, the materials dried in Bourma drier result in high percentages of scorched and broken kernels. Excessive brokens in subsequent peeling process is attributed to uneven and over drying of cashew kernels in the Bourma rendering it brittle. During the drying process the kernel shrinks, so that the testa is loosely adhered to the kernel and facilitates its removal. The testa is removed manually by special knives (made of metal, bamboo or wood) or by mechanical means. Since Bourma drying is a time consuming one and highly imperfect, infrared treatment of the kernel is being explored for achieving surface drying.
Reference may be made to the design of a modified through flow drier (Mathew et.al, 1972) in CFTRI wherein a provision for changing the direction of the air flow
through the bed of cashew kernels was made, which resulted in reducing the processing
time to a certain extent. Though the process reduced the drying time, the draw back of
this process was that it could not reduce the percentage of broken kernels and scorched
kernels in the end product.
The main object of the present invention is to provide an improved process for the
preparation of processed nuts, which obviates the drawbacks as detailed above.
Another object of the present invention is to facilitate the surface drying of the
nuts particularly cashew kernel by exposing it to infrared radiation and thereby reducing
the time, cost and kernel breakage.
Still another object of the present invention is uniform heating of the cashew
kernels and there by reducing the percentage of the scorched kernels in the processed
kernels.
In the drawing accompanying this specification figure 1 and fig 2 represents the
schematic diagram of the infrared-heating oven used for the processing of cashew kernel.
The heating oven in figure 1 consists of a closed heating chamber (1) fitted with an infrared heating source (2) on topside of the material holding aluminum tray (3). The temperature inside the heating chamber was measured with the help of a temperature probe (4) and the material was uniformly spread (5) over the holding tray. The heating oven in figure 2 consists of an insulated heating chamber (6) fitted with infrared heating source (7) on both top and bottom side of the stainless steel wire mesh tray (8). The cashew kernels with testa layer (5) were uniformly spread over wire mesh tray and the temperature of the oven was measured with the help of the probe (9) placed near the material bed.
Accordingly the present invention provides an improved process for the preparation of processed nuts, which comprises subjecting nut kernels to an infrared radiation at temperatures in the range of 75 -120°C, for a period of 14 - 30 minutes, cooling the infrared treated cashew kernels to the room temperature followed by removing testa and rehydrating in a known manner to get the processed nuts.
The process of the present invention can be utilized for other nuts such as groundnuts, pista, almonds.
In another embodiment of the process the testa is removed from the kernel manually or by mechanical means.
In the present invention, the cashew kernels with testa layer are stored for a week for equilibration of moisture content. These cashew kernels with testa layer are then exposed to infrared radiation. Two different heat sources, infrared bulbs with internal reflector and ceramic heater were selected so as to cover the entire range of infrared thermal radiation. The temperature inside the heating chamber was maintained at a specified value with the help of a thermostat depending on the type of nuts to be processed. The infrared radiation impinges on the surface of the cashew kernels and is absorbed by the kernels, which results in the increase in the surface temperature. The temperature increase leads to the removal of moisture from the surface which in turn results in the shrinkage of the testa layer, which facilitates the easy removal of testa. The infrared treated cashew kernels are then cooled to the room temperature and the red peel teata is removed either by hand or with the help a special purpose knife made out of bamboo or metal. Since the surface heating of the cashew kernels can be achieved at much faster rate with infrared heating than in case of conventional Bourma drying, the processing time is reduced significantly. The uniform heating of the cashew kernels with infrared radiation reduces the percentage of scorched kernels in the processed material in comparison with the conventional process. Uniform
heating coupled with accurate processing time reduces the chances of excess drying of the cashew kernels, which in turn reduces the percentage of broken or split kernels in the processed materials.
The following examples are given by way of illustration of the present invention and should not be construed to limit the scope of the present invention.
Example -1
500 gm of the cashew kernels with testa were stored for a week for equilibration of moisture and then used for experiments. The average moisture content of the cashew kernel was found to be 7.3% (d.b). The weight of 100 numbers of cashew kernels with testa layer was 200 gm.
Cashew kernels with testa layer were dried in an infrared oven schematically shown in Figure 1, which has a closed heating chamber (1) and a far infrared source (ceramic heater, 500W) (2). The cashew kernels with testa (5) were uniformly spread over the aluminium holding tray (3). The temperature of the oven was maintained at 100°C. The distance between the heat source and the material was maintained at 36mm. The temperature in the heating chamber was controlled by a thermostat. The cashew kernels were vigorously mixed during drying for uniform heating of the surface. The sample was drawn after 30 minutes and cooled in a desiccator in order to prevent the sample from absorbing moisture from the atmosphere. After the infrared treatment the testa layer was removed easily from the cashew kernel either by hand or by a special purpose knife.
Example 2
The drying operation was carried out in the infrared oven similar to Example 1, except for the fact that oven temperature was maintained at 120°C. The sample was
drawn after 17 minutes and cooled in a desiccator in order to prevent the sample from absorbing moisture from the atmosphere. After the infrared treatment the testa layer was removed easily from the cashew kernel either by hand or by a special purpose knife.
Example 3
1.0 kg of the cashew kernels with testa were stored for a week for equilibration of moisture and then used for experiments. The average moisture content of the cashew kernel was found to be 7.3% (d.b). The weight of 100 numbers of cashew kernels with testa layer was 200 gm.
Cashew kernels with testa layer were dried in an infrared oven schematically shown in Figure 2, having heating chamber (6) and a near infrared heating source (infrared bulbs with internal reflector)(7) on both sides of the wire mesh tray. The cashew kernels with testa (5) were uniformly spread over the stainless steel wire mesh tray (3). The temperature of the oven was maintained at 100°C. The distance between the heat source and the material was maintained at 85mm. The temperature in the heating chamber was controlled by a thermostat. The sample was drawn after 14 minutes and cooled in a desiccator in order to prevent the sample from absorbing moisture from the atmosphere. After the infrared treatment the testa layer was removed easily from the cashew kernel either by hand or by a special purpose knife.
Example 4
The drying operation was carried out in the infrared oven similar to Example 3, except for the fact that oven temperature was maintained at 75°C. The sample was drawn after 30 minutes and cooled in a desiccator in order to prevent the sample from absorbing
moisture from the atmosphere. After the infrared treatment the testa layer was removed easily from the cashew kernel either by hand or by a special purpose knife.
Example 5
250 gm of Groundnut seed kernels with testa layer were dried in an infrared oven schematically shown in Figure 2, having heating chamber (6) and a near infrared heating source (infrared bulbs with internal reflector)(7) on both sides of the wire mesh tray. Kernels with testa (5) were uniformly spread over the stainless steel wire mesh tray (3). The temperature of the oven was maintained at 100°C. The distance between the heat source and the material was maintained at 85mm. The temperature in the heating chamber was controlled by a thermostat. The sample was drawn after 5 minutes and cooled in a desiccator in order to prevent the sample from absorbing moisture from the atmosphere. After the infrared treatment the testa layer was removed easily from kernels manually.
Though the process of the present invention illustrated to use of cashewnuts, it can be implemented for processing other nuts such as here in described.
The main advantages of the present invention are
1. The process is easy to scale up and economic and results in value added product.
2. The kernel damage could be reduced substantially.
3. The process time could be reduced significantly from several hours (6 -7) to few minutes (14-30).
4. Due to uniform heating of kernels during processing high quality nuts can be
obtained.





















We claim:
1. An improved process for the preparation of processed nuts, which comprises subjecting nut kernels to an infrared radiation at temperatures in the range of 75 -120°C, for a period of 14 - 30 minutes, cooling the infrared treated cashew kernels to the room temperature followed by removing testa and rehydrating in a known manner to get the processed nuts.
2. A process as claimed in the claim 1, where in nuts such as cashewnuts, pista and groundnut preferably cashewnuts are used.
3. A process as claimed in claim 1 & 2 where in testa is removed manually.
4. A process as claimed in claim 1,2 & 3 where in the rehydration is carried out to have 5 - 6% moisture content.
5. An improved process for the preparation of processed nuts substantially as herein described with reference to the examples and drawings accompanying this specification.

Documents:

1562-del-1999-abstract.pdf

1562-del-1999-claims.pdf

1562-del-1999-complete specification (granted).pdf

1562-del-1999-correspondence-others.pdf

1562-del-1999-correspondence-po.pdf

1562-del-1999-description (complete).pdf

1562-del-1999-drawings.pdf

1562-del-1999-form-1.pdf

1562-del-1999-form-2.pdf

1562-del-1999-form-4.pdf


Patent Number 195186
Indian Patent Application Number 1562/DEL/1999
PG Journal Number 36/2008
Publication Date 05-Sep-2008
Grant Date 24-Nov-2006
Date of Filing 21-Dec-1999
Name of Patentee Council of Scientific and Industrial Research,
Applicant Address Rafi Marg,
Inventors:
# Inventor's Name Inventor's Address
1 Umesh Hebbar, Central Food Technological Research Institute,Mysore-570013
2 Navin Kumar Rastogi Central Food Technological Research Institute, Mysore-570013
3 Anantaswamyrao Ramesh Central Food Technological Research Institute, Mysore-570013
PCT International Classification Number A 23 L 1/36
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA