|Title of Invention||
PROCESS OF PNEUMATIC PRESSURE PADDY PARBOILING
|Abstract||A process of preparation of parboiling paddy where in the paddy is heated with steam upto 900 -950 C and hot water is filled into the pneumatic pressure vessel till water drains from over-flow nozzle and after closing the all values the pressure inside the pneumatic vessel is applied upto desired level of 4 kg/cm2 by operating air compressor and after attaining the desired pneumatic pressure in the vessel the nozzle connected to steam line is closed tightly to maintain pneumatic pressure constant throughout the process and after 2.5 hours of soaking, the water is drained and steam is sent at a temperature of 1000 -1100 C for two minutes in the vessel by opening the nozzle connected to stem line further the paddy is dried and milled.|
FIELD OF INVENTION:
The present invention relates to parboiled rice and to processes for its preparation
BACKGROUND OF THE INVENTION:
Parboiled rice is usually defined as rice that has been steeped, heat-treated and dried. During the heat treatment step of parboiling, the starch in the endosperm of the rice is substantially gelatinized. The parboiling process and the resulting gelatinization of the starch have several beneficial effects.
Paddy parboiling -a processing step aimed at getting more milled rice from paddy v/hich originated in India. It is being practiced in many countries including India, Bangladesh, Pakistan, Burma, Malaysia, Thailand, Italy, Spain, Uruguay, Brazil, France and the United states. About 70% of the paddy produced woridwide and more than 50% of paddy produced in South Asia is parboiled. Nearly 50% of the total paddy production in India is parboiled, predominantly in the states of Andhra Pradesh, Kerala, Tamilnadu, Orissa, Assam, Bihar and West Bengal. Parboiled rice is also eaten in the other states like Punjab, Uttarpradesh, Madhya Pradesh, Maharastra, Gujarat and Karnataka. The leading exporting country is Thailand followed by the United States. Parboiling has been practiced on a commercial scale in the United States, Italy and Gyana since 1940.
Advantages of Parboiling process: The Parboiling process imparts to the grain a hard texture and smooth surface finish, as a result the brokens in the milled rice is minimized. The reduction in broken rice results in an increase of 3 to 5% of total yield of rice.
Milled parboiled rice contains more of B vitamin (particularly Thiamin) than milled raw rice.
Loss of B - vitamins is less in parboiled rice during washing and cooking compared to that in raw rice.
The bran from parboiled contains higher oil content (about 25-30% oil) compared to raw rice bran (about 10-20%oil).
The cooking quality of parboiled rice is different from that of raw rice. Parboiled rice is non-sticky and non-glutinous.
Parboiled rice is produced in India, Bangladesh, Burma, Thailand, SriLanka and other Asian countries by both traditional and modern parboiling process.
Traditional process in commercial sector in Asian countries is in practice, in which paddy is steeped in water for 1-3 days. Sometimes raw paddy is dumped into ground level tanks containing water at room temperature and allowed to steep for 2-3 days. After draining the water, the paddy is transferred into kettles for steaming and then dried in the yards. The process is called single - steaming.
In other process termed Double - Steaming, raw paddy is pre-steamed for 15-20 minutes is put in water and allowed to steep for 12-24 hours. After the water is drained, the product is steamed and dried as described above.
In some traditional rice mills, steam is directly injected into the water in the ground level tank until its temperature raises 70-75"* C. Then the raw paddy is put into the these tanks and allowed to steep for 12-24 hours, then the water is drained, and the paddy is steamed in kettles and yard-dried to about 14%
moisture. In clear weather, drying is generally completed in a single day. However, during inclement conditions, drying is continued into the next day.
Some of the existing processes in different countries, which are very cumbersome and expensive, are as follows.
In India there are some of the different processes used in the process of parboiling.
Home made parboiling is the domestic process used for parboiling paddy where in paddy is placed in a brass - vessel or earthen pot or a container and covered with water container and is heated to boiling point until the grain swell.
Here gelatinisation is incomplete. Rice is not as hard as parboiled rice. Foul smell and coloured. Paddy cannot be milled. Hulling breakage is less. Leaching loss is present.
Sela is another process of parboiling existing in the state of Uttar Pradesh in India. Here paddy is steeped in water for 24 to 48 hours. Then removed from fire, mixed with sand and roaster for 5 minutes, while continuously being stirred.
Cold water soaking and steaming is also present in some areas where the paddy
is soaked in cold water for 1 to 3 days and stearried for 15 minutes in steaming
In this process the off colour & off odour is present. Leaching loss is present.
Pre-heated soaking & steaming is a process of parboiling in which either water is pre-heated to about 60° C or paddy is preheated by steaming for 15 minutes prior to soaking. Then steamed for 15 minutes in steaming tanks.
Here soaking time is reduced to 24 hours. Leaching loss, off colour and off odour are still present.
Cold water soaking with sodium chromate (developed by Paddy Processing Research Centre, Tiruvarur, India) & steaming is another process or method of parboiling. In this process 0 to 0.5% sodium chromate (1/2 kg of sodium chromate per tonne of paddy) is added to cold water and paddy is steeped for 1 to 3 days. Then steamed for 15 minutes in steaming tanks.
Here off odour is eliminated. Total head rice is increased by 1.5% Leaching loss is not eliminated.
Hot water soaking & steaming which is adopted in modern mills is another method of parboiling. Here paddy is soaked for 3 to 4 hours in hot water maintained at 65° C in soaking tanks. Further steaming is also done in the same tanks for 15 minutes.
Here off colour is present because of high temperature steeping and leaching loss is present.
Pressure parboiling is the process developed by Paddy Processing Research Centre, Tiruvarur, India. The intergranular moisture on wetted paddy is used for production of steam for vapour phase soaking and parboiling under steam pressure.
Here parboiling time is reduced. Leaching loss is eliminated. Off colour is present white bellies are present.
Methods available in United States of America are as follows.
H.R conversion process is one of the methods of parboiling. Paddy is steeped in hot water (75 to 85°C) for 120 to 165 minutes at a pressure of 15 to 20 Kg/sq.cm in an enclosed vessel. Paddy is introduced in to cylindrical rotating steam jacketed partially evacuated vessel. Then steam is introduced for sometime and blown off A vacuum of 70 75 cms is applied
Here grain is more resistant to insect attack. Retention of vitamins 92.45% of thiamine, 70-12% riboflavin, 77.62% of niacin in the original rice is present. But Leaching loss is present along with yellow colouring.
Match process is another method used in parboiling in United States in which paddy is soaked in water at 42° C for 6 hours. Then the paddy is steamed for 15 minutes at 15 psi.
Here Thiamine 2.0 mgm/gm of rice, Riboflavin 0.4 mgm/gm of rice, Niacin 44.0 mgm/gm of rice. Leaching loss is present.
Gariboldi's Rice parboiling process is another method available in parboiling. Cleaned paddy is steeped in hot water at controlled temperature. Then the paddy is steamed at controlled pressure in a special autoclave.
Here milling breakage is nil. Retains high nutritive value. No unpleasant smell during cooling. Leaching loss is present.
Methods available in Italy are as follows.
Avorio process is a method of parboiling present in Italy in which paddy is held in perforated basket and moved in hot water tank. Then the paddy is steamed in rotating cylinder. Here leaching loss is present.
Converted rice process is another method of parboiling available in the country where air is evacuated from the grains. Water at relative low temperature is forced in by hydrostatic pressure. Then steamed in cylinders, vacuum dried in the same cylinders. Here leaching loss is present.
Method available in Surinam is as follows.
Fernandes process is the method available for parboiling in the country. Here paddy is soaked in hot water. Hot water is passed through perforated sidewall of rotating cylinders fitted with screw conveyor. Then the paddy is steamed in the rotary cylinders of same construction.
Here leaching loss is present.
In counties such as Italy and United States, parboiling of rice has been fully automated. But in the major parboiled rice producing and consuming counties (i.e., India, SriLanka, Bangladesh and Burma) a semiautomatic process of parboiling is developed by the Central Food Technological & Research Institute (CFTRI, Mysore), is practiced in large milling installations. The facilities in such installations include 4-8 steeping vessels with built-in steam coils, hot water tank, pressure boiler, mechanical dryers with steam heat exchangers or husk-fired furnaces for drying paddy, and mechanical handling equipment.
The steeping vessels are filled with hot water at 80-85o C and the raw paddy quickly transferred into it from overhead surge bin. The water is circulated for 15-20 minutes and then maintained at 65o C for 6 to 8 hours, after which it is drained off. Steam is let into the built -in steam coils, and the paddy is steamed for 10-20 minutes and then moved to a dryer through belt conveyers.
DRAWBACKS OF THE PRIOR ART:
The current practice of paddy parboiling using steam in rice processing units involves long processing time of 6 to 8 hours. This results in large amount of steam consumption per tonne of paddy i.e., 200 Kgs of steam per tonne of paddy. Moreover, the resultant rice produced in the process has light yellowish brown colour due to long exposure to steam. Present - day, consumer do not prefer it.
OBJECTS OF THE INVENTION
Considering the short comings of the processes described in the prior art, there is every need to develop a method for the pneumatic pressure paddy parboiling which is comparatively a new concept in paddy parboiling particularly where pneumatic pressure is used to accelerate the rate of diffusion of water into paddy grain during soaking treatment. The process consists of soaking the paddy at an intermediate temperature of water under pneumatic pressure and giving steam to soaked grain at gelatinization temperature (GT) or above gelatinization temperature further drying of steam treated paddy and milling.
Accordingly, it is an object of the invention to provide an improved parboiled rice product.
It is yet another object of the invention to provide a parboiled rice product which process is completed in very shorter time.
It is an additional object of the invention to provide a parboiled rice product, which has all the advantages of conventional parboiled rice.
It is another object of the invention to provide a parboiled rice product that has not much colour change vis-a-vis that of typical raw rice with white colour.
It is another object of the invention to provide a parboiled rice product, which has soft texture.
It is still another object of the invention to provide a method for the preparation of the above-mentioned parboiled product.
SUMMARY OF THE INVENTION:
The machinery is novel equipment using a novel method of parboiling of paddy before it is milled. The process involves double steaming involving the first steam used to heat the paddy and second steam used for gelatinisation of paddy.
The Air inlet, hot water inlet, overflow/air vent, sight glass and Temperature Guage are fixed in the cylindrical portion of the pneumatic pressure vessel. The paddy inlet, Pressure Guage and safety valve are provided in the dished end of the pneumatic pressure vessel. The steam inlet, paddy outlet and drain are provided in the cone portion of the pneumatic pressure vessel.
Through this invention the time for processing is reduced from 8 hours (in Central Food Technological Research Institute, Mysore method i.e., commercial method of parboiling) to 2.5 hours. Through this process it produces white coloured and soft textured and shorter cooking time parboiled rice. Also facilitates deeper penetration of vitamins into the grains. Leaching loss is not present. The advantages are achieved only with the novel machinery and process as described in the next paragraphs.
DESCRIPTION OF DRAWINGS:
Fig 1 is the flow chart showing the process of the pneumatic pressure paddy parboiling.
DESCRIPTION OF THE INVENTION:
The above and other objective features and advantages will be clear from the following description.
This novel process involves double steaming in rts sequence of operations. First steaming is used to heat the paddy, second steaming is used for gelatinisation of paddy.
The process involves filling dry paddy in pneumatic pressure vessel through paddy inlet nozzle after pre-cleaning and open the steam valve for 2 minutes. During First steaming, steam at a temperature of 100o - 110o C will be sent through steam inlet nozzle for preheating the paddy to 90** - 95** C. After heating the paddy with steam upto 90** - 95o C, steam is turned off and hot water is filled into the pneumatic pressure vessel till water drains from over-flow nozzle. After hot water release, the paddy plus water temperature comes down to 80 - 85° C. This soaking temperature varies with paddy variety. The soaking temperature will be decided based on gelatinization temperature of paddy variety. The gelatinization temperature of paddy varies with variety. After attaining desired soaking temperature of 80" - 85** C, all nozzles are to be closed except nozzle connected to compressor. The pressure inside the pneumatic pressure vessel is applied upto desired level of 4 kg/cm^ by operating air compressor. After attaining desired pneumatic pressure in the vessel, the nozzle connected to compressor has to be closed tightly to maintain the pneumatic pressure constant throughout the process. When soaking was completed for 2.5 hours, the nozzle connected
to compressor has to be opened to release the pressure from the vessel and open the drain-out nozzle to drain the water.
After complete draining of water from the pressure vessel, close the drain-out nozzle and open the nozzle connected steam line. Then send the steam at a temperature of 100° - 110° C for two minutes in the vessel (Second steaming). After completion of second steaming, the paddy is taken out from the vessel by opening paddy outlet nozzle and dry the paddy upto 13% moisture content (wet basis) in the Louisiana State University (LSU) model mechanical drier for 5 to 6 hours and milling of dry paddy.
It will be understood that the above description is only illustrative of the present invention and is not intended that the present invention is limited thereto. Any other specific embodiment of the present invention will be apparent to one skilled in that art from the above disclosure. Any modifications of the present inventioin which comes within the scope of claims are to which the present invention is readily susceptible without departing from the spirit of the invention.
1. A process of pneumatic pressure paddy parboiling where in the paddy is
heated with steam up to 90o - 95° C, hot water is filled into the pneumatic
pressure vessel till water drains from over-flow nozzle, after attaining
desired soaking temperature of 800 - 85o C all nozzles are to be closed
except nozzle connected to compressor, the pressure into the vessel is
applied up to desired level of 4 kg/cm2, the nozzle connected to
compressor is closed tightly to maintain pneumatic pressure constant
throughout the process for 2.5 hours, then the water is drained through
drain out nozzle and again steam is sent at a temperature of 100° -110° C
for two minutes into vessel by opening the nozzle connected to steam line,
remove the paddy for drying upto 13% moisture content and milling to
attain soft textured, white coloured parboiled rice.
2. A process of pneumatic pressure paddy parboiling according to claim 1,
wherein the first steam soaking is completed in 2.5 hours.
3. A process of pneumatic pressure paddy parboiling according to claim 1,
wherein the temperature of the steam to be sent is of 100° -110° C.
4. A process of pneumatic pressure paddy parboiling according to claim 1,
wherein double steaming of operation is conducted as first steaming is
used to heat the paddy and second steaming is used for gelatinization of
|Indian Patent Application Number||545/CHE/2003|
|PG Journal Number||50/2007|
|Date of Filing||01-Jul-2003|
|Name of Patentee||NATIONAL AGRICULTURAL TECHNOLOGY PROJECT|
|Applicant Address||NEW DELHI, UNDER ICAR, GOVT. OF INDIA|
|PCT International Classification Number||A23 L 1/182|
|PCT International Application Number||N/A|
|PCT International Filing date|