Title of Invention

"A NOVEL PROCESS FOR DEHULLING OF NIGER SEEDS"

Abstract

A NOVEL PROCESS FOR DEHULLING OF NIGER SEEDS Provided herein is a novel process for denuding the Niger seed which comprises the steps of cleaning, grading, de-stoning and cooking the seeds in at optimum concentration. The hulls were separated by isopycnic method and drying to obtain dehulled seeds rich in oil and protein. The dehulled seeds were expeller pressed to obtain light coloured oil and cake. The defatted meal prepared from cake has high protein and low in fiber. The physicochemical and fattyacid composition of the oil is not changed. The flour has retained all the essential amino acids and the nutritional characteristics were improved in the dehulled flour. The process inactivates the trypsin inhibitor activity to not detectable level.

Full Text

The present invention relates to a process for the dehulling of Niger (Guizotia abyssinica, cass) seeds. Niger seed (Guizoiia abyssinica, cass) is an oilseed of considerable importance since ancient times. Oil recovered from the seeds is highly valued as edible oil. Niger is a member of the composite Heliantae genus, native to tropical Africa. It is a native of Abyssinia, now Ethiopia, where it is known as neuk, noog and nug. It is also widely grown in India and Pakistan. Presently, India produces about 2 lakh tonnes of Niger seeds. In India, it is grown in red sandy loam, light and deep black soils of Madhya Pradesh, Maharastra, Karnataka, Bihar and Andhra Pradesh. The crop is tolerant to saline conditions. The local name comprises of Kaltil. Sarguia, Tilangi, Karel and jartila. In Vedic literature it is called the wild sesame and it is called Huchchellu in Kannada. The whole Niger seeds resemble sunflower seeds in shape, but are much smaller in size (3.9 to 4.7 mm long), 1.5 mm in width almost lanceolate in shape without pappus, a fairly thick adherent seed coat, glossy, and usually black, but mottled seeds also occur occasionally. Normally 1000-grain weight is in the range of 3 to 5 gm. It can be stored for years without deterioration. Niger seed oil is pale yellow to orange in colour with slight odour and pleasant nutty taste. Niger seed oil is a semi drying oil since the linoleic acid content is very high and it is used to a limited extent as paint oil. Niger seed oil is used for cooking. The oil is a good absorbent of fragrance of flowers due to which it is used as base oil by the perfume industry. The oil contains 81% unsaturated and 18% saturated fatty acids. Among the unsaturated, oleic (26%) and linoleic acid (55%) are the major ones. The Niger seed oil is nutritious and contains higher levels of linoleic acid, which reduces blood cholesterol. The oil can be hydrogenated for obtaining a white solid fat. Proximate composition of Niger seed (Ootacamund variety) is presented in Table 1. It has high protein content (24%), fat (31%) and hull content (22%). Hull content in Niger seeds is high, but the proteins are nutritionally superior. Amino acid composition of the Niger seed protein is given in Table 6. It is slightly deficient in lysine and threonine, but all other amino acids are comparable to other edible oilseed proteins. Since Niger seed protein is a good source of sulphur amino acids, supplementation of edible quality Niger seed flour in foods will help to prevent malnutrition. The main limitations/ drawbacks in the use of Niger seed/meal for human consumption are: presence of outer cuticle, the fibrous hull fraction responsible for appreciable amount crude fibre. This also contributes to the dark colour of the meal and bitterness, reddish brown colour of the oil. Dehulling of the seed is the most satisfactory method to improve both appearance and nutritional quality. The best possible value addition for Niger seeds can be obtained by denuding the seeds, for producing good quality oil and edible quality light coloured cake. Dehulling /decortication of Niger seed is necessary, to use the denuded Niger seed cake for human consumption. Reference may be made to a paper entitled studies on the dehulling of sesame seed to obtain superior grade Protein concentrates, Shamanthaka Sastry. M.C., Subramanian.N., Raja Gopalan.R., wherein treating the sesame seed using different alkalis such as sodium bicarbonate, Sodium carbonate and sodium hydroxide. Among the three alkalis, sodium hydroxide was used at the concentration of 0.6% in the ratio of 1:1.6 w/v and boiling for 1 minute. The hulls were separated by air classification. Reference may also be made to a paper entitled process development studies on the wet dehulling and processing of sesame seed to obtain edible protein concentrates, Ramachandra.B.S., Shamanthaka Sastry.M.C., Subba Rao.L.S., wherein process development studies have been conducted based on the laboratory data for the wet dehulling of black sesame seed and quantitative data has also been presented for handling the material. Reference may also be made to a process know how of CFTRI, 1970, wherein the details of the process developed for dehulling the sesame seeds to obtain good quality dehulled sesame seed and further processing to obtain superior quality oil and meal from sesame seeds, has been elucidated. The present invention provides a process for dehulling Niger seeds by wet method which comprises of boiling the seeds in 4% sodium hydroxide in the ratio of 1:2 w/v for 4 minutes to achieve ~ 96% dehulling. The dehulled seeds were separated by isopycnic method. At present, the whole niger seeds are pressed for oil by using Ghani or Expeller. The oil and cake obtained will be dark in colour with high amounts of fiber. Hence.the technology of dehulling is essential to over come the problems. Dehulling the niger seeds results in good quality light coloured oil and cake with low fiber.ln the present condition, the oil Industries needs this type of integrated approach for better utilization of by products. The dehulled niger seeds along with the undehulled niger seeds (Fig. 1a) for comparison is shown in Fig.lb and c. There is no process/ method described in the literature for dehulling of Niger seeds. The main objective of the present invention is to provide a novel dehulling process for Niger seeds. Another objective is to enable enrichment of oil content in the seeds. Yet another objective is to improve quality of resultant oil. Still another objective is to produce high-protein, low-fiber dehulled seeds for producing high quality cake/ flour for food and feed uses. Another objective is to provide a continuous process for denuding Niger seeds. Accordingly, the present invention provides A process for the denuding of Niger seeds which comprises a. cleaning the niger seeds by conventional method, b. adding water in the proportion of 1:1 to 2.5 (w/v) and steaming for 1-2hr c. adding Alkali 2-7%, stirring and boiling at 90-97° C and stirred the mixture continuously for 2-8 minutes to obtain treated seeds, d. wasing the treated seeds with water to remove alkali and feeding the washed seeds into a pulper to remove the hulls to obtain the dehulled seeds, e. neutralizing the dehulled seeds mild acid 0.2-0.5% , f. treating the dehulled seeds along with hulls in brine solution contiaing sodium chloride 5-12%w/w concentration, g. collecting the dehulled seeds and drying at 60 to 70 °c for 3-4 hrs to a moisture level of 3-5%, In an embodiment of the present invention the mild acid used may be acetic acid. In another embodiment of the invention the alkali used is Sodium hydroxide. Suitable material handling and conveying systems are used to render the process continuous, and hygienic. Novelty of the process: The novelties of this Niger seed dehulling process are: • The use of alkali at optimum concentration and conditions such as time of cooking, water - seed ratio to maximize the dehulling efficiency. • The use of specific gravity principle for separation of hulls; use of suitable brine at optimum concentration for hull separation, • The color of the enriched oil is light, compared to the whole seed oil. • The protein content of cake is increased form 29% to 44%. • The process reduces the crude fibre content in the cake from 20 to 11 % • The process retains all the essential amino acids in the flour. • The nutritional characteristics of the flour are improved as compared to the whole seed flour. • Trypsin inhibitor activity is reduced from 13.8 + 1 TID/mg in the whole seed flour, to non-detectable levels in the dehulled seed flour. Following examples are given by way of illustration of the present invention only and therefore, should not be construed to limit the scope of the invention. Example -1 5 kg of Ootacamund variety of Niger seeds (7% m.c. wet basis) procured from the local market was subjected to cleaning cum grading, destoning and air classification to remove big, small, heavy and lighter impurities. Ferrous impurities were also removed using a magnetic separator (hopper bottom type). Refractions amounted to about 0.6 kg. Water in the proportion of 1:2 (w/v) was taken in the steam kettle and brought to a temperature of about 96° C. NaOH (4%) was added and stirred. Measured quantity of cleaned and graded Niger seeds were added to the boiling solution held in the kettle and was heated to bring the mixture to boiling. The mixture was continuously stirred for about 4 minutes. The alkali treated seeds were transferred to a perforated basket and a water wash was given to remove alkali adhering to the grains. Washed seeds were fed in to the pulper with water. Pulper, fitted with suitable sieves was run at a low speed. The mixture of dehulled seeds and hulls was collected. The dehulled kernels along with the hull fractions were neutralized by giving a mild wash with 0.5% acetic acid washed with potable water and drained. The mixture of dehulled seeds and hulls was subjected to gravity settling in brine (8% w/w concentration) held in SS kettle. The mixture was intermittently stirred and left for settling. The dehulled seeds were topped off. Hulls were collected separately. After water washing, dehulled seeds were dried in a cross flow drier (air temperature below 60°C) to a moisture of 4%. Dried seeds were aspirated in an air classifier to remove the hull fractions by adjusting the air velocity. The hull fraction was also drained of excess water and dried in a cross flow drier, and finished products and by-products were bagged. Weight of fully dehulled kernels was 3.2 kg at 5 % m.c (w.b.), amounting to an yield of 65.6%, (on cleaned grain basis); 67 % on cleaned grain basis on equal moisture basis. The quality of oil, cake (obtained by ghani pressing/ expelling) and flour obtained is as shown in tables 3 to 6. Example -2 5 kg of Ootacamund variety of Niger seeds (7% m.c. wet basis) procured from the local market was subjected to cleaning cum grading, destoning and air classification to remove big, small, heavy and lighter impurities. Ferrous impurities were also removed using a magnetic separator (hopper bottom type). Refractions amounted to about 0.4 kg. Water in the proportion of 1:2 (w/v) was taken in the steam kettle and brought to a temperature of about 96° C. Required quantity of the NaOH (4%) was added and stirred. Measured quantity of cleaned and graded Niger seeds were added to the boiling solution held in the kettle and was heated to bring the mixture to boiling. The mixture was continuously stirred for about 4 minutes. The alkali treated seeds were transferred to a perforated basket and a water wash was given to remove alkali adhering to the grains. Washed seeds were fed in to the pulper with water. Pulper, fitted with suitable sieves was run at a low speed. The mixture of dehulled seeds and hulls was collected. The dehulled kernels along with the hull fractions were neutralized by giving a mild wash with 0.5% acetic acid washed with potable water and drained. The mixture of denuded seeds and hulls was subjected to gravity settling in brine (8% w/w concentration) held in SS kettle. The mixture was intermittently stirred and left for settling. The dehulled seeds were topped off. Hulls were collected separately. After water washing, dehulled seeds were dried in a through flow drier (air temperature below 55°C) to a moisture of 4.5%. Dried seeds were aspirated in an air classifier to remove the hull fractions by adjusting the air velocity. The hull fraction was also drained of excess water and dried in a cross flow drier, and finished products and by-products were bagged. Weight of fully dehulled kernels was 3.00 kg at 4.8 % m.c (w.b.), amounting to an yield of 65.2 %, (on cleaned grain basis); 66.8 % on cleaned grain basis on equal moisture basis. The quality of oil, cake (obtained by ghani pressing/ expelling) and flour obtained is as shown in tables 3 to 6. Example -3 15 kg of commercial variety of Niger seeds (7% m.c. wet basis) procured from the local market was subjected to cleaning cum grading, destoning and air classification to remove big, small, heavy and lighter impurities. Ferrous impurities were also removed using a magnetic separator (hopper bottom type). Refractions amounted to about 0.7 kg. Water in the proportion of 1:2 (w/v) was taken in the steam kettle and brought to a temperature of about 94° C. NaOH was added and stirred. Measured quantity of cleaned and graded Niger seeds were added to the boiling solution held in the kettle and was heated to bring the mixture to boiling. The mixture was continuously stirred for about 4 minutes. The alkali treated seeds were transferred to a perforated basket and a water wash was given to remove alkali adhering to the grains. Washed seeds were fed in to the pulper with water. Pulper, fitted with suitable sieves was run at a low speed. The mixture of dehulled seeds and hulls was collected. The dehulled kernels along with the hull fractions were neutra.ubd by giving a mild wash with- 0.5% acetic acid washed with potable water and drained. The mixture of dehulled seeds and hulls was subjected to gravity settling in brine (8% w/w concentration) held in SS kettle. The mixture was intermittently stirred and left for settling. The dehulled seeds were topped off. Hulls were collected separately. After water washing, dehulled seeds were dried in a fluidized bed drier (air temperature below 55°C) to moisture of 4.5%. Dried seeds were aspirated in an air classifier to remove the hull fractions by adjusting the air velocity. The hull fraction was also drained of excess water and dried in a cross flow drier, and finished products and by-products were bagged. Weight of fully dehulled kernels was 8.85 kg at 4.5 % m.c (w.b.), amounting to an yield of 62 %, (on cleaned grain basis); 63.6 % on cleaned grain basis on equal moisture basis. The quality of oil, cake (obtained by ghani pressing/ expelling) and flour obtained is as shown in tables 3 to 6. The main advantages of the present invention are: 1. The process provides a method for dehulling of Niger seed (3.9 to 4.7 mm long; ~1 -5 mm wide) with a dehulling efficiency of 96-98%. 2. Dehulled Niger seeds could be the source of oil/Protein. 3. The protein and fat content of the dehulled seed increased form 24 to 35% and 31 to 53% respectively. 4. The crude fiber content of the Niger seed reduced from 17% to 2-2.5% 5. The oil extracted from the processed seed was lighter in color. 6. The oil from dehulled Niger seeds has low free fatty acid content. 7. No change in the physicochemical characteristics and fatty acid composition of the processed oil. 8. The cake obtained after Ghani pressing contained high protein (44%) and low fiber (11%) compared to whole seed cake. 9. The processed flour retained all the amino acids present in the starting material and trypsin inhibitor activity is reduced from 13.8 + 1 TlU/mg in the whole seed flour to non detectable levels in the dehulled seed flour. 10. The 7n vitro' digestibility of protein was higher for dehulled flour (85.5%) compared to undehulled seed flour (76%). 11.The calculated nutritional indices such as Essential Amino Acid Index, Biological Value and Nutritional Index were higher than the undehulled flour. 12.The C- PER calculated based on the amino acid composition with reference WHO pattern was 2.5 and comparable to casein. We claim: 1. A novel process for dehulling of niger seeds which comprises: [a] cleaning the niger seeds by conventional methods; [b] adding water to the cleaned seeds of step [a] in a proportion of 1: 1 to 2.5 (w/v) and steaming for 1 to 2 hours; [c] adding 2 to 7% of an alkali of the kind such as herein described to the steamed seeds of step [b] followed by stirring and boiling at 90 to 97°C and re-stirring the mixture for 2 to 8 minutes to obtain treated seeds; [d] washing the treated seeds of step [c] with water to remove alkali and feeding the washed seeds into a pulper to remove the hulls so as to obtain the dehulled seeds; [e] neutralizing the dehulled seeds of step [d] with 0.2-0.5% of a mild acid; [f] treating the seeds of step [e] along with hulls in brine solution containing 5-12%w/w sodium chloride; [g] collecting the brine treated seeds of step [f] and drying at 60 to 70 °C for 3-4 hrs to a moisture level of 3-5% to obtain the desired dehulled niger seeds. 2. A process as claimed in claim 1, wherein the mild acid used is acetic acid. 3. A process as claimed in claim 1, wherein the alkali used is sodium hydroxide. 4. A novel process for dehulling of niger seeds substantially as herein described with reference to the foregoing examples.

Documents:

0281-del-2003-abstract.pdf

0281-del-2003-claims.pdf

0281-del-2003-correspondence-others.pdf

0281-del-2003-correspondence-po.pdf

0281-del-2003-description (complete).pdf

0281-del-2003-form-1.pdf

0281-del-2003-form-18.pdf

0281-del-2003-form-2.pdf

0281-del-2003-form-3.pdf

281-DEL-2003-Abstract-(29-12-2008).pdf

281-DEL-2003-Claims-(29-12-2008).pdf

281-DEL-2003-Form-1-(29-12-2008).pdf

281-DEL-2003-Form-3-(29-12-2008).pdf