WO2006029636A1

WO2006029636A1 - Post harvest process for treatment of rice to reduce loss and increase nutrition value

Info

Publication number: WO2006029636A1
Application number: PCT/EG2004/000036
Authority: WO
Inventors: Abdol Ghader Mohammed Memari
Original assignee: Abdol Ghader Mohammed Memari
Priority date: 2004-09-13
Filing date: 2004-09-27
Publication date: 2006-03-23

Abstract

The present invention relates to Post Harvest process for treatment of Rice to reduce loss resulting from the normal handling of Rice and increase nutrition value thereof. The process of the invention comprises: 1 - pre-cleaning of paddy Rice. 2 - Soaking or steeping of paddy grains in water to increase its moisture content to 20% - 45, preferably from 25% - 35%. 3 - Thermal treatment of the wet paddy grains by steam for the specified duration to complete the biochemical changes. 4 - Drying the paddy grains to moisture level safe for milling. The invention includes also a milling and polishing of paddy rice.

Description

Post Harvest process for treatment of Rice to reduce loss and increase nutritional value. Technical field of the invention:

The present invention relates to post - harvest process for the treatment of Paddy grains. In particular, the invention relates to treatment of rice varieties " SORNA PEARL1" and " SORNA PEARL2 " to decrease loss result in post harvest handling and increase the nutritional values of the rice.

Background of the invention: More than half of the population of the world depends on rice, which is grown on nearly 150 million hectares of land for a global production of more than 520 million tones. Wetlands where rice grows in flooded fields during all or part of the cropping period make up about 80% of worlds rice area accounting for 93% of all rice production. It is estimated that by the year 2020 the annual demand for rice will exceed 760 million tones as world population swells to 8 billion, more than half of whom will be rice consumers. This production increase of almost 40% will have to be achieved on about the same amount of Riceland than it is cultivated today - or even less. It is possible to increase the rice production considerably by adopting modern rice production technologies. High yielding dwarf varieties and Hybrid rice varieties have greater potential coupled with Integrated Nutrient Management (INM) and Integrated Pest(s) Management (IPM) would increase the yield per unit area in wetland rice. Human Resource Development (HRD) among Rice Scientists, Rice Technicians, Innovative farmers also would play significant influence in increasing not only yield of rice per unit area but also for quality rice production. Also attempts are made to improve the quality rice productions with rich nutrients in rice grains. Also attempts are made to exploit Biotechnology tools to achieve higher Rice Production. The International Rice Research Institute, Los Banos, The Philippines is the world leader in Rice Research is involved continuously by addressing various issues on rice production including for the development of "transgenic rice" for protecting from the pest(s) and disease(s), abiotic stress and quality rice by incorporating genes for increasing Vitamin - A.

From a yield sustainability standpoint traditional wetland rice cultivation has been extremely successful. Moderate but stable yields have been maintained for thousands of years without deterioration of the environment. But maintaining the sustainability of rice producing environments in the face of increased demands will require new concepts and agriculture practices which in turn will require increased knowledge of the ecology of the complex floodwater rice eco system.

Flooding is especially important for maintaining Soil nitrogen fertility when rice is grown year after year without added Nitrogen fertilizer.

Prior Art : Attempts have been made in the prior art to improve the yield of Rice but all these attempts concentrated on chemical treatments and control of weeds in Rice fields.

Nishikawa et al, discloses in US Patent No 5,173423 a process for breeding a glabrous var. of Rice crop, this process comprising steps of culturing tissues from a target Rice plant, culturing the calli formed to regeneration medium, growing the regenerates and selecting glabrous plants there from. Klittich et al, discloses in US patent number 6,261 ,996 a pre-germinated rice seed comprising a plant growth regulator and further comprising phytoprotection product specially insecticide. Colliot et al, disclose in US patent process for the agrochemical treatment of Rice. The process comprises applying to Rice plant effective amount of insecticide other than organophosphorus.

Most recently, Yamanaka, discloses in the Us published patent application a method of growing rice plants wherein abundant and trace elements which significantly influence the growth of rice plants are incorporated into rice plant to improve nutritional balance in Rice and thereby eliminate the influence of insects causing damages to crops and eliminates the need of spraying agrochemicals which adversely affect the human body. Technical Background:

Rice belongs to genus Oryza and family poaceae. The genus includes 24 species of which are 22 are wild and 2 species viz.; Oryza sativa and Oryza glaberrima are cultivated. The most common variety used specially in Asia, Africa and Europe Belongs to Oryza sativa. The variety used in West Africa belongs to Oryza glaberrima. Oryza sativa has three sub types:

• Oryza sativa var indica

• Oryza sativa var japonica

• Oryza sativa var javanica

Cultivation of Rice needs special standards in respect of soil, climate, irrigation and weed control. The soils on which rice grows are as varied as the climatic regime to which the crop is exposed. The texture of soil ranges from sand to clay, pH from 4 to 10, organic matter content from 1-50%, salt content from almost 0-1 % and nutrient availability from acute deficiencies to surplus. Rice can be grown on a variety of soils ranging from water logged and poorly drained to well drained.

Productivity of land used for growing rice is to a large extent determined by soil and water conditions. Rice is the only major annual food crop that grows well on land that is saturated with water or even submerged, during part or all of its growth cycle.

Rice is also grown under many different climatic and hydrologic conditions. There is a considerable range in pedo-genetic and morphological characteristics of rice growing soils. Wherever possible, the soil is kept flooded or at least saturated with fresh water throughout the growing period of rice corp. Flooded soils may undergo profound changes like: Soil minerals also play an important role in Rice productivity. Understanding of clay minerals is important for management of rice soils, which supports good rice crop and higher productivity. Both clay content as expressed by texture and clay mineralogical characteristics have great bearing on the productivity of soils. In most Asian rice soil with montmorillonitic clay have higher fertility and higher yield potential than soil with Kaolin minerals or soils with allophone minerals as the major clay constituents. Clay minerals play a significant role in physical and chemical properties of the rice soils. The layer thickness of clay minerals is different for different groups and ranges from 0.7 nm to 1.4 nm.

Flooding of rice soils provides a favourable environment for anaerobic microbes and the biochemical changes are varied and numerous. The major types of microbes are present in lowland rice soils in variable proportion. Rice is cultivated in different seasons using different methods in different parts of the world. Depending upon the planting season the duration of variety plays a major factor in the selection of a variety. Based on the duration of varieties, they are grouped into 5 categories:

• Very short duration: up to 100 days

• Short duration: 101-120 days

• Medium duration: 121-140 days

• Long duration: 141-160 days • Very long duration: Above 161 days

But in vogue only three groups are agronomically important and they are short duration, medium duration and long duration. There are three common seasons:

• Autumn rice: June to Sep (90-120 days) Φ Kharif ήce: June to Oct (110-120 days)

• Rabi rice: June to Sep (120-130 days)

Among the Rice verities, which are suitable for cultivation in all three season, is Soma Pearl - 2 Rice, which is widely adopted for cultivation and lapse 120-125 days.

In most Asian countries wetland Rice village is common. Puddling has been widely adopted because it provides ease of transplanting. Puddling is a simple soil operation that eases transplanting and reduces water losses through percolation. Puddling results in reduction of moisture losses by percolation. Puddling reduces percolation losses of moisture, decreasing aggregate cohesion thereby essentially eliminating macro-porosity and increasing bulk density. Transplanting of seedlings is taken up in the well- prepared main rice field. Transplanting of Rice can be made in two ways

1 - Random Transplanting :ln this type, seedlings are planted at random in the field. The distance from plant to plant is not uniform and not definite pattern is followed. 2 - Line Transplanting: In this method rice plant with a spacing of 6"x6" or 6"x9" -spacing between rice plant and row are being adopted. This method is efficient for intercultural operations like weeding, spraying and top dressing etc., which will reflect on higher yield per unit area. The rice grain is also called caryopsis featuring a closely adherent pericarp and seed coat. The Rice Kernel is enveloped by a husk, which is very tough. The husk contains a high proportion of silicic acid, apart form crude fibre. The second multi layer skin, called the bran layer tightly envelops the endosperm. It is rich in minerals, vitamins, fats and proteins. The germ contains a high proportion of fat. The endosperm essentially contains starch, water and protein.

Post-harvest treatment represent an important feature of the Rice production and the importance of post-harvest handling of rice has increased because of the higher yields possible from the modern high yielding rice varieties. Losses that had been small in absolute terms expanded proportionately with increased farm level yields. And the emphasis on increasing rice production by increasing cropping intensively resulted in a crop to harvest at the height of the wet season rice, dictating substantial changes in post-production operations. When the paddy grains are harvested, it is unusable as human food until the inedible hull is removed. Since the grain is usually consumed as white rice, the bran layer must also be removed through a process called polishing or milling. Thus the normal sequence in the handling of a rice crop after it matures is harvesting, cleaning, drying, storage, milling and distribution to the market or retaining for farm family consumption. Parboiling or steaming process is undertaken before milling.

In general loss of rice grain has been determined to fall within the following ranges. During harvest and post-harvest operation: 13-34%

During harvesting and threshing: 5-15%

Cleaning and drying: 2-3%

Storage: 2-6% Processing (Steaming/Parboiling and milling): 3-7%

Handling and Transport: 1-3%

In other words 26% up to 68% of the Rice grain can be lost for due to post harvest handling and for other reasons such as deterioration, under utilization of by products and financial losses due to inefficient post-harvest operations.

It is an object of this invention to significantly reduce losses of Rice grain post harvest.

Brief descritopn of the drawing: Fig ( 1 ) flow chart of the stage 1 of the process of the invention Fig ( 2 ) flow chart of the stage 2 of the process of the invention Fig ( 3 ) flow chart of the stage 3 of the process of the invention

Detailed description of the invention. The present invention relates to post - harvest process for the treatment of paddy grains. In particular, the invention relates to treatment of rice varieties ¹¹ SORNA PEARL1" and " SORNA PEARL2 " to decrease loss result in post harvest handling and increase the nutrition values of the rice.

The present invention relates to process for treatment of Rice grains to reduce loss of grain during handling and increase nutrition value of rice grain. Variety used in this invention was Soma Pearl, Soma Pearl -1 and Soma Pearl -2. This Rice Variety is grown in wetland fields with river irrigation. Paddy seedlings are transplanted in rows by adopting modern rice production technology. Crop management is taken up with recommended levels of organic and inorganic fertilizers and adequate care is taken up for controlling pest and diseases by using both bio-pesticides, bio-control agents and also with minimum use of in-organic process. The inter cultivation operation is also done to control the weed populations. The crop is irrigated periodically with 3" to 4" water stagnation. After earhead formation, the crop is allowed to mature till complete grain ripening stage observing for Golden yellow colour. During maturity stage irrigation is withheld. Before harvest, paddy earhead are collected at random from the field and checked for its complete maturity. The crop is harvested manually and the earheads with paddy straws are allowed to sundry in the field itself for a minimum of 24 hours. The process of the invention is hydrothermal treatment of paddy grains prior to milling. In the steaming process paddy grains is soaked for a specific duration, steamed under optimum pressure and for a specific duration and dried before milling process. Steaming of grains result in several advantages including: • Steaming process gelatinizes the starch within the rice grain thus causing swelling and fusion of starch within the kernel.

• Pre-steaming moisture content of 15-20% and 26 cal of heat/kg of paddy grains is needed.

• Steaming plays an important role in the process. The right degree of steaming is arrived at and maintained consistently to obtain the desired results to achieve minimum broken rice and also to improve the nutritional value and quality.

The process of the invention includes the following steps:

1 - Soaking or steeping of paddy grains in water to increase its moisture content to 20% - 45%, preferably from 25% - 35%.

2 - Thermal treatment of the wet paddy grains by steam for the specified duration to complete the biochemical changes.

3 - Drying the paddy grains to moisture level safe for milling.

In one embodiment of the invention, the rice grains are pre-cleaned before subjecting to the process of the invention.

Soaking of the paddy grains is made for the period required to increase the content of moisture of grains to the above-mentioned range. Grains having the required content of moisture are directed to Steaming process which is made in a 3 pass boiler at a pressure of 5 - 15 Kg/sq.cm, preferably 6 to 12 kg/sq.cm, and most preferably 7 to 10.5 kg/sq.cm. Grains are subjected to steam for a period of 5 minutes up to 60 minutes, preferable from 10 minutes up to 45 minutes and most preferably from 11 minutes to 35 minutes.

Steamed grains are dried by flow of hot air for a period required to retain moisture content within the range of 10 to 18 %, preferably 12 to 16%. Advantages of steaming process of the invention includes: • Easier de hulling

• It is consumer preference

• Reduction in the number of broken grains during milling, because the grains are strengthened during steaming.

• Harder grains which are less vulnerable to insect attack during storage. • Steamed milled rice is richer in the B-Vitamins than milled raw rice.

• Cooked steamed rice is less sticky than freshly harvested raw rice.

• Cooked rice is more by volume basis by 15-20%.

• Cooked rice is good for mixing with any spicy curry and also good for Briyani preparation Vegetable, Chicken or Mutton Briyani.

• The invention will be better understood by reference to the attached drawings. Fig (1 ) shows the first stage of the process of the invention wherein paddy Rice (1 ) is used. In the first step it is weighted in (2) through any kind of weighting machines e.g electronic measuring apparatus. Weighted grains are directed to drum grader (3) whereas haystacks and threads are removed (4) and collected at (5). Pre cleaned grains are subjected to classifier (7) wherein large, small and light impurities are removed (6) and collected in (9). Grains free from large, small and light impurities are directed to de-stoner (11 ) to remove stones (10) and collect it in (13). Pre-cleaned grains subjected to the above cleaning steps are subjected to mechanical drying (15) by hot air (16). Dried grains are directed to tanks (18) for storage and soaking to increase the content of moisture to be within the range specified above. Once the grain attained the required moisture content at is directed to steaming tanks (19) whereas it is subjected to steam from steam source (20) at the steam pressure specified above and for the period specified above. Steamed grains are subjected thereafter to mechanical drying (22) by hot air (16). Second stage of the process is illustrated in Fig (2); this process is directed to milling of rice grain. Paddy is pre-cleaned in 3 steps to remove foreign material including stones. Fig (2) elicit the milling process, steamed rice is stored in tower (30) for a period not less than 24 hours. In the first step of pre-cleaning process Rice grains from storing tower are directed to separator (31 ), which removes immature grains, and collect it in (32). In the second step, grains are thereafter subjected to classifier (33) to remove light impurities and collected in (34). In the last step, grains coming from classifier (33) are directed to vibrator (35) whereas stones are removed and collected in (36) step of the pre cleaning. Cleaned paddy is de husked in the Top Husker' (37) whereas husk is separated. Husk is taken out by the Venturi fan (38) and guided to husk storage unit (39) and / or steam boiler (40). The output mixture of brown rice, un-hulled paddy is passed on Paddy separator (41 ) Paddy separated in the separator is sent back to the Top husker (37) whereas Brown rice is guided to the Rotosort (42) to sort out grains and thick grains are removed and collected in 43 whereas other grains directed to the third stage of the process.

Polishing process is illustrated in Fig (3); brown rice from the previous stage is conveyed to a series of 3 Top white polishers (50, 51 , 52) to produce polished rice. The bran by-product from the 3 Top white polishers is collected in (53). Collected bran is also separated into pure bran, which is collected in (54) and waste bran, which is also collected in (55). Output of the 3 top polishers is directed to rotosort (56) to remove immature grains at (57). Rice is then polished by the High poly polisher (58) to obtain silky, pearly, high luster rice and bran is also directed to (54). The mixture of whole and broken rice obtained during polishing is separated and graded in vibratory Plansifter (59) whereas broken grains are separated and collected in (60). The remaining mixture of whole and left over broken rice obtained from the vibratory plan sifter is separated and graded in an Indent cylinder (61 ) whereas broken grains also directed to (60).

After grading, the whole rice and various grades of broken rice are weighed on automatic scales and bagged. Head rice is now guided to a packing machinery for automated packing.

It should be noted that in carrying out the polishing process Rice is forced to move quickly in a circular motion around its feeding axle, rubbing against each other at high pressure and very high speed. As rice grain is rubbing against each other at very high speed so breakage is minimal. Due to high pressure and friction, part of surface is rub out and grain temperature increase rapidly to over 350 F for hard polishing with Water droplet and air current is then introduced to rice and it will moisten rice surface As rule of rice gelatinization, rice, which is starch, will gelatinize if enough heat and water are present. In this machine, hot rice surface will gelatinise after added with water droplet. Then rice will come to next chamber where dry air is introduced so rice surface dry quickly leaving only its surface gelatinized. During polishing, part of rice surface rubbed against each other so some surface with dust and bran is rub off, hence rice is cleaner. After rice surface is gelatinized, it will be a thin layer of shiny dried gelatinized starch giving the gram a pearly white, smooth and glossy touch.

Preferred embodiment of the invention

Five rice samples viz., IR.64, Jaya, Ponni, Soma Pearl, Basmathi are compared with three sample prepared according to the process of the invention namely Soma Pearl -1 and Soma Pearl-2 were they were all tested for chemical constituents. The proximate components such as moisture, proteins, Total Fat, Carbohydrate, Crude Fibre, Energy, Starch and Dietary Fibre were analyzed by standard test methods. The minerals of the rice samples i.e., Phosphorous, Sodium, Potassium, Calcium and Iron contents were analyzed by adopting standard methods. The amino acids like Lysine and Methionine levels in the sample were estimated by standard method. Gylcemic Index was also tested for all rice varieties. The result of these analyses are shown in the following tables: Table (1)

* = By calculation **=SP:18(PARTIII); 1984. NT. = Not tested.

Table (2) Mineral Composition

Table (3)

Amino Acid Content

Table (4) Heavy Metal content

= ICPOES

Table (5) Glycemic Index

As noted from the above table:

1.The variety Soma Pearl has recorded higher energy value of 365.66 K.cals when compared to other rice varieties tested. 2. Soma Pearl -2 has recorded the highest dietary fibre value of 2.4%.

Dietary fibre rich cereal has better food value along with higher proteins and other minerals and amino acids.

3. The crude fibre content of Soma Pearl Rice is also relatively higher

(0.35%) when compared to other varieties. 4. The starch contents of Soma Pearl -2 and Soma Pearl recorded low value of 76.91 % and 77.92% when compared to other rice varieties.

5. Soma Pearl-2 also recorded higher fat content of 0.98% but between varieties.

6. Seven varieties contain fairly rich amounts of these minerals, which are important for the metabolic activity of human beings. Among the seven rice cultivars Soma Pearl-2 has recorded comparatively higher mineral contents except potassium content but rich in calcium level, which is very important nutrient in the metabolism of human beings.

7. Interestingly, all the three varieties of Soma Pearl viz, Soma Pearl, Soma Pearl — 1 , and Soma Pearl — 2 have recorded low Glycemic Index values of 51 %, 55% and 44% respectively.

Diabetic management is generally followed by the use of starchy foods with low Glycemic index and low Glycemic response and as shown in the above table the three varieties of Soma Pearl viz, Soma Pearl, Soma Pearl — 1 , and Soma Pearl — 2 have recorded low Glycemic Index values which make it as suitable for Diabetic patient since hyper Glycemic in diabetic patient is considered a risk factor for developing micro-vascular and possibly also macro-vascular complications and the later on may lead to death.

It is to be understood that the subject invention is not to be restricted to the exact description set forth herein which are given by way of example. Various variation and modifications can be made all fall within the scope of the invention.

Claims

1 ) Post - harvest process for the treatment of Rice grains comprises: 1. Subjected paddy grain to pre- cleaning process.

2. Soaking or steeping of paddy grains in water to increase its moisture content.

3. Thermal treatment of the wet paddy grains by steam for the specified duration to complete the biochemical changes.

4. Drying the paddy grains to moisture level safe for milling.

2) Post - harvest process for the treatment of Rice grains according to claim 1 whereas content of moisture is increased to 20% - 45, preferably from 25% - 35%.

3) Post - harvest process for the treatment of Rice grains according to claim 1 whereas steaming process is carried out with a 3 pass boiler at a pressure of 5 - 15 Kg/sq.cm, preferably 6 to 12 kg/sq.cm, and most preferably 7 to 10.5 kg/sq.cm.

4) Post - harvest process for the treatment of Rice grains according to claims 1 and 3 whereas subjected to steam for a period of 5 minutes up to

60 minutes, preferable from 10 minutes up to 45 minutes and most preferably from 11 minutes to 35 minutes.

5) Post - harvest process for the treatment of Rice grains according to claim 1 whereas steamed grains are dried by flow of hot air.

6) Post - harvest process for the treatment of Rice grains according to claims 1 and 3 whereas drying is continued for a period required to retain moisture content within the range of 10 to 18 %, preferably 12 to 16%.

7) Post - harvest process for the treatment of Rice grains whereas obtaining a head rice is made in three stages: A - Stage 1 whereas paddy grains are subjected to process according to claims 1 - 6.

B - Stage 2, milling process whereas Rice grains are directed to separator which removes immature grains and collect it in, grains are thereafter subjected to classifier to remove light impurities, grains are directed to vibrator whereas stones are removed.

Cleaned paddy is de husked in the Top Husker' whereas husk is separated.

The output mixture of brown rice, un-hulled paddy is passed on Paddy separator. Paddy separated in the separator is sent back to the Top husker whereas Brown rice is guided to the Rotosort to sort out grains and thick grains are removed and other grains directed to the third stage of the process.

C - Stage 3, polishing whereas paddy grains obtained from step one are subjected to a series of 3 Top white polishers, rotosort to remove immature grains; Sorted rice is then polished by the High poly polisher to obtain silky, pearly, high luster rice. Broken rice grains are separated using a Sifter and an indent cylinder to give full rice grain output.

8) Post - harvest process for the treatment of Rice grains according to claim 7 whereas the output paddy grains resulting from the first stage are stored for period not less than 24 hours.

9) Post - harvest process for the treatment of Rice grains according to claim 7 whereas cleaned paddy rice are subjected to Top Husker¹ whereas husk is taken by Venturi fan and either collected or feeded to steam boiler.

10) Post - harvest process for the treatment of Rice grains according to claim 7 whereas brown rice is guided to the Rotosort to sort out grains; thick grains are removed and collected and other grains directed to the third stage of the process. 11 ) Post - harvest process for the treatment of Rice grains according to claim 7 whereas 3 Top white polishers are used to polish the brown rice.

12) Post - harvest process for the treatment of Rice grains according to claim 11 whereas polished grains are sorted to remove thick grains.

13) Post - harvest process for the treatment of Rice grains according to claim 11 whereas sorted grains are subjected to High poly polisher to obtain silky rice.

14) Rice grain produced in accordance with process of claims 1 - 6 .

15) Rice grain produced by process according to claims 7 - 12.

16) Rice grain suitable for diabetic patients produced according to claims 1- 6. or process according to claims 7-12.