FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
Patent Rules 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)
1. Title of the invention. Low Glycemic Index Rice and process of manufacture
thereof
2. Applicant - (a) Marico Ltd
(b) "Rang Sharda"
Krishnachandra Marg Sandra Reclamation Bandra (West) Mumbai - 400050 Maharashtra, India
(c) an Indian Company.
The following specification particularly describes the invention and the manner in
which it is to be performed

Field of the Invention
The invention relates to post harvest process to produce Low Glycemic index rice.
Background and Prior art.
Controlling the slow digestible carbohydrates and the resistant starch (RS) in rice plays significant role in the nutritional management [Journal of Cereal Science, 40 231-237 (2004)]. It has been established that increase in the resistant starch content by about 1.6% results in a decrease of Glycemic Index (Gl) of about around 30%. Approaches to achieve low Gl rice, has been through "Parboiling" as it offers significant advantages such as improved milling, storage qualities, nutrient availability and organoleptic properties besides enhancing the resistant starch content. Parboiling is essentially pre-cooking the rice in the form of Paddy followed by drying and milling. Generally parboiling processes involve extended soaking of the rice in hot water for more than 30 minutes to 6 Hours, followed by completely draining and high pressure steaming to reduce Gl. These processes are complicated and resource intensive in terms of water requirement (4:1) to paddy, and higher lead times due to soaking, draining and followed by intense High pressure steaming [Journal of Agric. Food Chem, 14,476-479 (1996)].
Other approaches in the literature disclose methods that involve soaking the rice with selected herbs followed by thermal / hydrothermal treatment of the rice.
Indian Patent Number 204608 discloses a process for parboiling paddy rice or cargo rice, comprising steeping said rice in water at a temperature lower than 70°C for at least three hours that, after drainage or spin-drying, steeped rice is obtained having a moisture content by weight greater than 31%, then in carrying out a gelatinization of the, steeped rice by heating it to a temperature greater than 130°C while maintaining the moisture thereof at a content by weight greater than 20% for a sufficient period to obtain core-gelatinized rice, characterized in that said process includes carrying out gelatinization by causing the steeped rice to pass continuously into an enclosure so as to limit, by virtue of the equilibrium which is established

within the enclosure between the moisture content of the rice which is undergoing gelatinization and the moisture content of the gaseous atmosphere of the enclosure, the quantity of vapor emitted from the rice during gelatinization, in order to maintain the moisture content by weight of the rice in the course of gelatinization at a value greater than 20%, and by heating the steeped rice in the enclosure essentially by conduction so as not to increase the moisture content by weight of the gelatinized rice appreciably.
Indian Patent Number 209914 discloses a process for preparing parboiled rice that is suitable for rapid cooking comprising:
a) parboiling rice with an amylose content lower than 15% by weight relative to dry matter in water at a temperature of 40 to 70°C, so that, after removal of the surface water by drainage or spin-drying, parboiled rice is obtained having a moisture content between 31 to 33 percent;
b) heating the rice from step (a) in steam so that at least 98% of the rice grains when placed in a 1.7% solution by weight KOH for 20 hours are completely translucent grains; and
c) drying the rice from step (b).
KR 20090025039(A) discloses a process in which cereals with Gl index lower than 60 are mixed. The mix comprises 30wt% of brown rice, 10wt% of brown rice with sea tangle, 8wt% of black rice, 15wt% of rye, 5wt% of pressed barley, 5wt% of black soybean, 7wt% of soybean, 3wt% of brown soybean, 5wt% of glycine max, 5wt% of kidney bean, 1wt% of peanut, and 1wt% of peeled green gram. The process of preparing brown rice with sea tangle involves the collecting, drying and high-temperature processing of natural sea tangle to obtain sea tangle extract(a); polishing and washing the brown rice; and coating the sea tangle extract on the brown rice.
US 2008220145 (A1) discloses a method of producing parboiled rice that does not require waste water treatment equipment and that enriches the amount of gamma-

aminobutyric acid contained in the parboiled rice. The method includes partially milling raw material brown rice, wetting the partially milled rice grains in a range between 16% and 19% by weight by forced-air using moist air or mist wherein the temperature is not less than 50°C and humidity not less than 90% in said wetting step, and moisture-tempering the wetted rice grains at or above 50 °C, steam-boiling the water-tempered rice grains at normal pressure to heat the rice grains with steam, steam-boiling the rice grains heated in the normal pressure steam-boiling process using pressurized steam, cooling the rice grains steamed under pressure in the pressurized steam-boiling step to cool at least a surface of the rice grains, finish milling the rice grains cooled in the cooling step, and drying the finish-milled rice grains.
US 5427810 discloses a method for hydrothermally treating a non-parboiled starch containing product, wherein the product has a water content attained by absorption of water, the method comprising the at least quasi-continuous process steps of: inserting the product into a heating unit at atmospheric pressure; supplying heat energy to the product in the heating unit at atmospheric pressure until boiling temperature of the product is attained, the product being moistened prior to said heat energy supplying step in order to reach a predetermined content of absorbed water in the starch product; inserting the product into a heat-retaining vessel; moving the product through the heat-retaining vessel via movement in a first direction; maintaining the boiling product within the heat-retaining vessel at atmospheric pressure so as to keep the product at an automatically controlled boiling temperature during a predetermined period, the maintaining being accomplished by flowing a heated medium in a second direction transverse to said first direction across a path of the movement of the product; inserting the product into a drying zone; and at least partially drying the product in the drying zone after completion of said maintaining step. In this process the heating of the moistened rice is done for 10 to 40 minutes and the said predetermined content of absorbed water is approximately 30% to 35%.

None of the methods described in the prior art specifically teach how to produce Low Gl rice.
Indian Patent Application No.0043/CHE/2006 discloses a parboiling process to reduce Gt comprising the steps of soaking paddy in a herbal solution prepared from herbs having hypoglycemic activity for a period of about 6 hours at a temperature of about 70°C to 130°C to facilitate complex starch formation and sweltering the soaked paddy at a pressure in the range of 14 to 25 psi and a temperature of 100 °C -150 °C for a period of 4 to 7 minutes to form high resistance starch.
The known multistep processes involve either wetting or soaking the rice to moisture levels greater than 20% followed by fairly harsh hydrothermal treatment.
We have surprisingly found that it is possible to achieve low Gl rice with fairly high resistant starch under mild conditions avoiding all the shortcomings of the prior art.
Summary of the invention
The main object of the invention is to provide a process to produce low Gl rice from selected rice varieties without subjecting the harvested rice to conventional soaking followed by high pressure steaming to increase resistant starch content.
Another object of the invention is to provide guidelines for the selection of the variety of rice for treatment using the invented process for the production of low Gl rice.
Description of the invention
Current invention involves process which is significantly different from other existing
parboiling / hydrothermal treatments employed for Paddy to lower the Gl to less than.
55
The process described herewith (illustrated in figure 1) comprises of the following
steps:
1. Selection of paddy

2. Saturation of the paddy with steam
3. Active Steaming of the paddy
4. Tempering
5. Drying
6. Cooling
7. Optionally milling and polishing
The present process involves selection of harvested paddy that is about at least 3 months old, with Amylose content of >27 %. The selected paddy is equilibrated to moisture content of around 9-15%. The equilibrated paddy is subjected to steaming at around 50-120 PSI followed by tempering to ensure heat transfer to the kernel of the rice. During this process the starch undergoes partial gelatinization wherein the degree of gelatinization is less than 50% in the absence of any excess moisture (>15%).
Steaming time comprises of a saturation time and active steaming time during which the paddy is subjected to a constant flow of steam at prescribed pressure. The preferable pressure is 50-120PSi.
The saturation time is the time taken to saturate the paddy in the treatment/processing vessel and is expressed in units of time/ton. For paddy with bulk density of 0.4-0.6 the saturation time ranges from 3 minutes/ton to 12 minutes /ton. Bulk density of paddy is preferably about 0.4-0.5 and the saturation time is preferably about 3- 8 minutes/ton. The active steaming time is generally 10-25minutes.
During tempering the steamed paddy is held at 80°C-150°C for a period of time ranging from 45-150 minutes preferably 90-120 minutes.

Drying of the tempered Paddy is done to achieve moisture content of around 9-14% and then cooled to about 20°C to 50°C. The treated paddy is optionally milled and polished.
Steaming increases the insoluble Amylose content by ~1.5 - 2%, there by increases the dietary fiber and decreases carbohydrates. Increase in the insoluble fraction leads to formation of amylose lipid complex and increases the resistant starch content due to the partial gelatinization leading to the lowering of Gl to less than 55.
Rice obtained by the above process when subjected to invitro as well as in vivo studies post cooking indicated a Gl of less than 55 as compared to the raw rice which generally has Gl of 60 - 80.
The present invention results in a significantly flexible process, lowers production costs as it excludes hot water soaking for 30 minutes to 6 hours which is used in conventional process, lowers the steaming time and drying time. The resistant starch content increases by about 40% which is significantly higher than that obtained by conventional methods.
The invention is illustrated by non-limiting examples.
Examples
Example 1
6 Months Paddy of ADT-43 with bulk density of 0,54 was equilibrated to moisture content of around 13-14% moisture, about 32% amylose and 15% insoluble amylose was subjected to norma! steaming conditions at 50 psig for 20 minutes. This steaming time consists of 15 minutes of saturation (7.5 min/ton for paddy with bulk density of 0.54) time followed by 5 minutes of active steaming time. This is then followed by tempering for about 100 minutes and drying to 11-12% moisture. Further the processed paddy is cooled and milled.

Example 2
6 Months Paddy of ADT-43 with bulk density of 0.54 was equilibrated to moisture content of around 13-14% moisture, about 32% amylose and 15% insoluble amylose was subjected to normal steaming conditions at 50 psi for 35 minutes. This steaming time consists of 15 minutes of saturation (7.5 min/ton for paddy with bulk density of 0.54) time followed by 20 minutes of active steaming time. This is then followed by tempering for about 100 minutes and drying to 11-12% moisture. Further the processed paddy is cooled and milled.
Example 3
6 Months Paddy of ADT-43 with bulk density of 0.54 was equilibrated to moisture content of around 13-14% moisture, about 32% amylose and 15% insoluble amylose was subjected to normal steaming conditions at 50 psig for 50 minutes. This steaming time consists of 15 minutes of saturation (7.5 min/ton for paddy with bulk density of 0.54) time followed by 35 minutes of .active steaming time. This is then followed by tempering for about 100 minutes and drying to 11-12% moisture. Further the processed paddy is cooled and milled.
Example 4
New Paddy ADT-43 equilibrated to moisture content of around 13-14% moisture, about 30% Amylose and 14% insoluble Amylose was subjected to steaming at about 50 psig for 50 minutes. This includes 15 minutes of saturation time and 35 minutes of active steaming time. This is then followed by tempering for about 100 minutes and drying to 11 -12% moisture. Further the processed paddy is cooled and milled.

The results of the examples 1-4 are given in table 1
Table 1

Parameters (dry basis) Raw Material Example 1 Example 2 Example 3 Example 4
Amylose 32.0% 32.0% 32.0% 32.0% 29.7%
Insoluble Amylose 15.3% 16.4% 17.0% 17.0% 14.6%
Resistant Starch 2.8% 3.0% 4.4% 3.9% 2.36%
Glycemic Indiex (Gl) 80 72 54 78 66.6
Example 5
6 Months old Paddy of CR-1009 with bulk density of 0.55 was equilibrated to moisture content of around 13-14% moisture, about 21.2% Amylose and 8.8% insoluble Amylose was subjected to normal steaming conditions at 50 psig for 20 minutes. This steaming time consists of 15 minutes of saturation (7.5 min/ton for paddy with bulk density of 0.54) time followed by 5 minutes of active steaming time. This is then followed by tempering for about 100 minutes and drying to 11-12% moisture. Further the processed paddy is cooled and milled. The results of the example 5 are given in table 2.
Table 2

Parameters Raw Material Example 5
(dry basis)
Amylose 21.12% 21.12%
Insoluble 8.3 8.8%
Amylose
Resistant 1.78 1.89
starch
Glycemic 78 80
Index

Example 6
6 Months old Paddy of PUSA-1 with bulk density of 0.46 was equilibrated to moisture content of around 13-14% moisture, about 31% Amylose and around 17% insoluble Amylose was subjected to normal steaming conditions at 50 psig for 20 minutes. This steaming time consists of 15 minutes of saturation (3-4 min/ton for paddy with bulk density of 0.46) time followed by 5 minutes of active steaming time. This is then followed by tempering for about 50 minutes and drying to 11-12% moisture. Further the processed paddy is cooled and milled. The results of the example 6, are given in table 3.
Table 3

Parameters Raw Material Example 6
(dry basis)
Amylose 31% 31%
Insoluble 17% 17.5%
Amylose
Resistant 3.7 % 3.9%
starch
Glycemic 63 52
Index
Example 7
6 Months old Paddy of PUSA-1121 with bulk density of 0.50 was equilibrated to moisture content of around 13-14% moisture, about 31% Amylose and around 17% insoluble Amylose was subjected to normal steaming conditions at 50 psig for 20 minutes. This steaming time consists of 15 minutes of saturation (6 mm/ton for paddy with bulk density of 0.46) time followed by 5 minutes of active steaming time. This is then followed by tempering for about 50 minutes and drying to 11-12% moisture. Further the processed paddy is cooled and milled. Tne results of the example 7, are givan in table 4.

Table 4

Parameters Raw Material Example 7
(dry basis)
Amylose 31 % 31 %
Insoluble 16.5% 18%
Amyiose
Resistant 3.2% 3.9%
starch
Glycemic 67 48
Index
The invention discloses a process wherein the selected rice is processed by equilibration of harvested paddy to moisture content of 9-15%, saturating the equilibrated paddy with steam at 50 to 120 PS! for 3 minutes/ton to 12 minutes/ton preferably at 3- 8 minutes/ton, active steaming of the steam saturated paddy for 10-25 minutes, tempering at temperature of 80°C -150°C for 45-150 minutes, preferably at 90-120 minutes, drying to moisture content of 9-14% preferably 11-13%, cooling to 20°C to 50°C and finally milling to produce low glycemic rice with Gl< 55.

We claim:
1. A post harvest process to produce Low Giycemic index rice comprising steps:
• Selecting the paddy
• Equilibrating the selected paddy to a predetermined moisture content
• Saturating the equilibrated paddy with steam
• Active Steaming of the steam saturated paddy
• Tempering
• Drying
• Cooling
• Optionally milling and polishing wherein post processed giycemic index is <55.

2. A post harvest process to produce Low Giycemic index rice as claimed in claim 1 wherein the paddy is selected from those that are aged for atleast 3 months.
3. A post harvest process to produce Low Giycemic index rice as claimed in any of the preceding claims wherein the paddy is selected from those with bulk density of 0.4-0.6.
4. A post harvest process to produce Low Giycemic index rice as claimed in any of the preceding claims wherein the paddy is selected from those with amylose content of > 27% and equilibrated to moisture content of 9-15%, preferably to moisture content of 13-14%.
5. A post harvest process to produce Low Giycemic index rice as claimed in claims 1-4 wherein the steam saturation is carried out at 50 to 120 PSl for 3 minutes/ton to 12 minutes /ton, preferably at 3- 8 minutes/ton.
6. A post harvest process to produce Low Giycemic index rice as claimed in claims 1-5 wherein active steaming time is 10-25 minutes preferably 10-20 minutes.
7. A post harvest process to produce Low Giycemic index rice as claimed in claims 1-6 wherein the tempering is carried out at 80°C-150°C for 50-150 minutes.
8. A post harvest process to produce Low Giycemic index rice as claimed in claims 1-7 wherein the tempering is carried out till the starch undergoes partial gelatinization wherein the degree of gelatinization is less than 50%

9. A post harvest process to produce Low Glycemic index rice as claimed in claims
1-8 wherein the drying is carried out to moisture content of 9-14% preferably 11.
13%.
10. A Post harvest process to produce Low Glycemic index rice as claimed in claims 1-9 wherein the treated rice is cooled to 20 °C to 50°C.