Title of Invention

"A PROCESS FOR THE PRODUCTION OF OIL AND OLEORESIN FROM FRESH GINGER RHIZOMES "

Abstract

The invention relates to a novel process for the production of oil and oleoresin from fresh Ginger Rhizomes ( Zingiber officinale Roscoe). The essential oil and oleoresin has far superior flavour qualities to the ginger oil and oleoresin hitherto known and produced commercially elsewhere from dried ginger. The process steps consists of preparing paste of cleaned fresh ginger, dewatering of the paste by conventional pressure technique to get aqueous phase and solid cake, recovering oil from aqueous phase and solid cake by distillation retaining the fresh flavour of ginger, combining the oil obtained from both phases to get oil, extracting the cake residue after distillation with permitted organic solvent, recovering solvent and blending the oil and solvent exttractives to get oleoresin.

Full Text

The present invention relates to process for the production of oil and oleoresin from fresh Ginger Rhizomes {Zingiber officinale Roscoe). This invention leads to the production of an essential oil and oleoresin with flavour qualities far superior to the ginger oil and oleoresin hitherto known and produced commercially elsewhere from dried ginger. Ginger powder, ginger starch and soluble ginger flavour suitable for soft drinks are the useful byproducts in the process. The major products of this novel process, viz. oil and oleoresin, can be used for flavouring all types of processed foods, beverages, bakery items, sweets etc wherein the available dried ginger flavour is now being used. The new products have got an added advantage of the fresh ginger flavour characteristics. Fresh ginger flavour is always rated superior organoleptically to dried ginger flavour. Sundrying of ginger rhizomes normally takes about 2-3 weeks and about 30-40% of the volatile oil is lost during this long drying period. Low boiling constituents which are the prime contributors of the characteristic fresh ginger flavour account for the major portion of this volatile oil loss. Geranial and neral, together known as citrals, are the major constituents responsible for the said flavour and they are present in the low boiling fraction of ginger oil. Volatile oil content and original flavour quality are taken care of in the novel process. Thus fresh ginger processing for oil and oleoresin aissumes signiflcance both from economic and quality point of view. The byproducts of the process add to the economic advantage of the process. In the novel process, fresh rhizome is the starting material and avoids the long sundrying step thus facilitating the direct processing of the fresh spice in growing regions. The spoilage of the produce under unfa\ourable climatic conditions and problems of transportation of the fresh material in bulk to drying or marketing centres are thus overcome and ginger growers can get better returns for their produce. No method or process is known in commerce now for production of value-added products of oil and oleoresin directly from fresh ginger. All known products of ginger oil and oleoresin are prepared from dried ginger. However, some earlier attempts reported on direct processing of fresh ginger are mostly on the preparation of total extractives of ginger including its essential oil and gingerols the pungent principles. Work carried out on extraction of Jamaican green ginger (Ashurst. P.R.; Firth. A.R. and Lewis, O.M. A new approach to spice processing, in Proc. Conf.Spices, Nabnery, Land Mathews, W.S.A., Eds. Tropical Products Instimte, London, 1973, 209) using warm acetone or alcohol eliminating the intermediary step of drying introduced large quantities of water in the extract thus raising the temperature during the removal of solvent and thereby affecting the quality of the product. Low temperature, high vacuum removal of the solvent was not economically viable and liquid-liquid extraction of the partially concentrated extract with hexane resulted in very poor yield of the oleoresin. Studies on preparation of oleoresin from fresh ginger paste using different solvents viz. hexane, dichloroethane and hexane-acetone (3:2) and also by double stage steam distillation followed by extraction reported yields in the range of only 0.3-0.9% on wet basis at 85-90%) moisture level compared to 6-7% from dry ginger of 10-12% moisture content (Table 1). Hexane was found to be the most suitable solvent for extraction with an yield of around 0.5-0.6% and according to the authors it is economical to obtain volatile oil from fresh ginger oleoresin as compared to direct steam distillation of fresh rhizomes. Ginger oil was thus recovered from the oleoresin and the overall yield was poor and the solvent removal step in the oleoresin preparation will definitely result in loss of low boiling constiments, thus affecting the oil quality [ Damayanthi, K.S.; Radha, R.and Kalyanaraman, Volatile oil and Oleoresin from Ginger, in Proceedings of National Seminar on Ginger and Turmeric.Nair. M.K., Premkumar, T., Ravindran, P.N. and Sarma, Y.R., Eds., Central Plantation Crops Research Institute, Calicut, 1980, 194]. In another study [Mathew, A.G., Krishnamurthy, N., Nambudiri,E.S., and Lewis, Y.S., Oil of Ginger, Flavour Ind., 4,226, 1973], green ginger obtained from the local market was chipped and dried by different techniques and the yield of oil and its quality characteristics were recorded (Table 2). The best quality oil was obtained from fresh green ginger and the fresh ginger oil sample was obtained by steam distillation of the thoroughly disintegrated spice for many hours. The problems encountered in steam distillation of the fresh spice are the very slow release of oil and the requirement of a bigger capacity' of the still, about 10 times that used for the corresponding quantity of dried ginger. In another attempt on processing of fresh ginger [Narayanan, C.S.; Rajaraman, K.; Sankarikutty, B.; Sumathykutty, M.A. and Mathew, A.G. Spice oleoresin with fresh flavour, in Proceedings of PLACROSYM III Seminar, George,K.V..Ed., Cardamom Board, Cochin, Nov. 1980, 99], the fresh spice was disintegrated and pressed to get juice and residue and the juice was subjected to various treatments viz. extraction with hexane, ethyl alcohol, ethyl acetate and ethylene dichloride, vacuum distillation and purging with nitrogen gas. Only hexane extractives gave a satisfactory product and the dried and ground residue was extracted using ethylene dichloride and the juice extractives was then blended with the residue extractives. The blended sample though had fresh juice extractives in it was judged as not having any superior fresh flavour compared to chipped and dried ginger oleoresin. This is be due to loss of low boiling volatiles from the extractives in the solvent removal step and also during drying of the residue before extraction. Also scale up studies resulted in processing problems like emulsion formation and very poor yield of fresh flavour extractives. In reports on azeotropic dehydration and extraction in production of concentrates from fresh ginger [Krishna, B.H.; Azeotropic dehydration and extraction in production of concentrates from materials bearing essential oil and other active principles. Report to the CSIR. New Delhi, 1973] raw ginger was pressed to separate juice and cake and solvent extraction of the juice was used to dehydrate cake by azeotropic distillation. Residue extract was reused for extraction of fresh material. In another process of obtaining oleoresin from fresh ginger [Damodaran, A.D.;Sreekumar, M.M.; Sankarikutty, B.; Nirmala Menon. A.; Gopalakrishnan, M.; Howa Umma and Narayanan, C.S., An Improved Slurry-Solvent Extraction Process for the Recovery of Oleoresin from FreshGinger , Indian Patent Application No.287/DEL/93 dated 23/3/93], ginger slurry was passed through a reciprocating plate column filled with the solvent phase in a counter-current fashion. The sluny was broken up into very fine droplets by the action of the reciprocating plate, thus facilitating fast transport of the oleoresin from the aqueous solid phase into the organic phase. The extract coming out of the column was desolventised to recover the oleoresin with typical fresh flavour characteristics. Oleoresin yield was very low compared to that from dried ginger. Sundrying of ginger rhizomes which normally takes about 2-3 weeks usually results in volatile oil loss of about 30-40% and drying affects also the quality of oil and oleoresin. The percent citrals content in the oil always parallel the rank order for quality. The total citrals content in fresh ginger is reduced from 15-20% to less than 5% and sometimes even to trace amounts in sun-dried ginger oil. Other changes reported in the oil during drying are the rearrangements of the major fresh ginger oil constituents, viz. zingiberene and P-sesquiphellandrene to ar-curcumene. The pungency of ginger is due to gingerols. a mixture of the homologues of 1-(1=-hydroxy, 3'-methoxy phenyl)5-hydroxy alkene-3-ones with smaller quantities of shogaols, zingerone and paradol and traces of other related compounds. The two major chemical changes in gingerol during drying and processing of ginger viz. dehydration and retroaldol reaction are undesirable since they lead to development of off-flavours in the product. Shogaol, product of dehydration from gingerol, has got a higher pungency value compared to gingerol. Thus the differences in flavour characteristics between fresh and dried ginger may be explained based on the above-said chemical changes during drying and processing. Oil quality from chipped and mechanically dried, freeze-dried, vacuum dried ginger etc. have been studied and found to have better flavour characteristics compared to sun-dried oils though not equivalent to fresh ginger oil. However, the said methods of drying of the bulk produce in the growing areas are very expensive. Ginger growers in many major growing areas face problems of transportation of the bulk produce without spoilage over long distances and also marketing of their whole produce in the fresh form is not assured. Unfavourable climatic conditions during harvesting seasons result in improper drying leading to spoilage and quality changes of the spice. Thus fresh ginger processing for oil/oleoresin assumes .significance both from economic and quality point of view. Loss of volatiles to the extent of 30-40% during sundrying is prevented in the novel process and results in higher yield of the above products. Energy saving (steam and electrical power) results in reduced cost of production. Also ginger oil and oleoresin processed directly from fresh ginger have superior flavour characteristics to the corresponding products of dried ginger. The main objective of the present invention is to provide a novel process for the production of oil and oleoresin from fresh ginger rhizomes which obviates the drawbacks as detailed above. Another objective of the present invention is to provide a method for obtaining ginger powder with superior flavour characteristics to dried ginger powder which may be used directly for oleoresin extraction, pickling, flavouring processed foods etc. Still another objective of the present invention is to provide a method for obtaining soluble fresh ginger flavour which may be directly used for preparing ginger-flavoured soft drinks. Yet another objective of the present invention is to provide a method for the isolation of ginger starch powder with functional properties suitable for use in various processed foods. Accordingly the present invention provides a process for production of ginger oil and oleoresin from fresh ginger which comprises preparing paste of fresh ginger by conventional methods, substantial devvatering of the ginger paste by applying conventional pressure technique to get aqueous phase and solid cake, recovering oil from aqueous phase and solid cake separately by conventional distillation methods retaining the full fresh flavour of ginger, combining the oil from both the phases to get the total oil, extracting the cake residue obtained after distillation v/ith permitted organic solvents followed by desolventisation by known methods and finally by blending the oil and solvent extractives to get the oleoresin. In an embodiment of the present invention, ginger paste may be prepared by grinder-mixer. In another embodiment of the present invention, dewatering of ginger paste may be carried out by hand press or hydraulic press. In yet another embodiment of the process, the oil may be recovered from juice by simple or solid cake distillation and steam distillation, and the residue may be directly extracted using permitted solvents viz. ethyl alcohol, dichloroethane or hexane-acetone mixture for the oleoresin. In another embodiment of the present invention, soluble and dilute fresh ginger flavour which can directly be made use of in formulating ginger-flavoured soft drinks is provided. In yet another embodiment of the present invention, solid cake after distillation can directly be made use of as ginger powder for its pungency. Still another embodiment of the present invention provides a method for isolation of ginger starch powder which is reported to have ftinctional properties suitable for use in various processed foods. The following procedure has been developed for the processing of fresh ginger (Zingiber officinale Roscoe) to get oil and oleoresin as the main products. Freshly harvested ginger rhizomes are cleaned free of mud in a washing tank and the final cleaning is done by spraying water on to the ginger using a high pressure pump. The cleaned ginger is subjected to size reduction and reduced to a paste form using a hammer mill. Alternatively an ordinary grinder-mixer is also used for making the paste. The mashed-up ginger is manually fed into the screw press for dewatering. Some juice released during the mashing-up operation is also mixed with the juice collected in the dewatering step. Alternatively hydraulic press and simple hand press are also used for dewatering in different experiments. Fresh ginger contains 85-90% moisture. Moisture content is substantially removed in the compression process and the compression ratio is so adjusted that about 80-90% of the total moisture is removed from the material. In another experiment for more effective Juice removal, equal weight of water is added to the residue obtained in the first pressing, mixed well and again subjected to pressing. Third pressing is also done in the same way. The juice obtained in the first, second and third pressing are combined together to have the total juice. Separation of solid and liquid phases is effected by centrifugation and filtration also in other experiments . The juice so obtained is allowed to settle for 5-8 hours for separation of starch. The juice is decanted and starch is washed with water free of juice and the washings are combined with the original juice. Starch is then dried and can be used as edible starch in food products. Essential oil is recovered from the juice by simple distillation. The juice from ginger contains about 60-70% of the oil present in fresh ginger. The liquid mixture is simply boiled and the vapours condensed using a condenser to recover the oil. Alternatively, oil is recovered by indirect heating, steam distillation and also simple distillation after diluting the juice with water to get more or less the same yield of oil. Towards the end of distillation, i.e. after about 1-2 hours of simple distillation steam is sparged through the still to release the left-over oil. The spent juice which contains traces of oil and a little pungency can be used for making soft drinks. Essential oil is recovered from cake by steam distillation. For the distillation of cake, the material is loaded in the still, steam is admitted into the jacket for pre-heating the vessel as well as the load and then directly admitted into the still. The steam carries along with it the vapours of the essential oil and get condensed in the-condenser. The rate of release of the oil is dependent on the steam flow rate. The condensate is allowed to flow into the oil/water separator. The oil/water separator is a three chamber vessel in which the oil rich condensate is collected in the first chamber and the water is allowed to flow into the second chamber from the bottom of the first chamber. The oil being lighter will rise up the column of water and is skimmed off firom the surface. The still will contain some water condensed and collected at the bottom. This contains about 0.1-0.2% oil and it is mixed with the juice for distillation to recover the oil. Alternatively, the cake is subjected to hydrodistillation after mixing with water in the ratio 1:3 to get comparable yield of oil. The condensate of distillation collected in the oil/water separator contains traces of dissolved oil and hence can be mixed with the spent juice for use in ginger-flavoured soft, drinks. The spent cake after distillation contains ~ 75-80% moisture and is dried mechanically at 55-60°C. The dried solid is powdered and can be used as a substitute for ground dried ginger also. This powder is directly used for oleoresin extraction using ethylene dichloride as solvent in the ratio 1:4. Alternatively alcohol and hexane-acetone mixture are also used as solvents in the ratio 1:4 for getting comparable yields of oleoresin. Extractions of wet cake after distillation are also done and ratio of material to solvent is kept as high as 1:5 for getting comparable yield. The solvent extract after desolventisation by distillation under vacuum followed by removing the traces of solvent in a thin film evaporator is mixed with required quantities of essential oil to get the total oleoresin with fresh flavour. The yields of essential oil from the juice and cake under optimised conditions of distillation are 80-85% and 70-75% respectively. The original oil content in the fresh rhizomes, juice and cake is estimated by hydrodistillation using a clevenger trap in the laboratory. The volatile oil content in the juice is in the range of 0.3- 0.4% and that of cake is 0.75-1.0% in the different experiments tried with fresh ginger having an oil content of 0.4-0.6%. The overall yield of essential oil in the novel process under optimised conditions is in the range of 0.3-0.35% and that of oleoresin is 1-1.2% based on fresh ginger. In the present invention, a new approach is made to fresh ginger processing in separating out its fresh flavour. The solid and liquid phases obtained in the dewatering step are subjected to steam distillation and simple distillation respectively to recover the fresh oil in good yield. As mentioned under prior art, all the earlier attempts in fresh ginger processing were aimed at direct distillation of the fresh spice or extracting out the total oleoresin using solvents followed by desolventisation. In some cases, isolation of the fresh oil was attempted from the oleoresin also. Slow release of flavour constituents from the firesh material and desolventisation step resulted in very poor yield and quality of the fresh flavour. In the novel process the fresh ginger is substantially dewatered during which step the essential oil is distributed between the solid and liquid phases approximately in the ratio 2:5. Dewatering is the most crucial step in the process by which -90% of the water present is removed from the fresh material having a moisture content of 85-90%. thereby reducing drastically the bulk to be handled in further steps of distillation and extraction. Also the oil release is much faster from both the liquid and solid phases than in the case of crushed whole fresh ginger or ground dried ginger, thereby reducing the number of hours required for distillation. The oil is recovered from the aqueous phase by simple distillation and from the solid phase by steam distillation for maximum oil recovery. Oil obtained from both the phases are combined together and the combined oil represents the fresh ginger oil with the typical fresh spice note. The solid is extracted using permitted solvents such as ethylene dichloride or ethyl alcohol and the extract desolventised and then blended with the required quantities of the fresh ginger oil to get oleoresin. Whereas all the earlier attempts on processing of fresh ginger resulted in poor oil and oleoresin recovery, higher yield and better quality oil and oleoresin retaining all the fresh ginger aroma constituents are obtained by this novel process. The following examples are given by way of illustration and therefore should not be construed to limit the scope of the present invention Example 1 100 kg freshly harvested ginger rhizomes of 87% moisture and 0.5% essential oil (estimated by Clevenger trap) were cleaned free of mud as described in the general procedure. It was subjected to size reduction using a hammer mill. The masked up ginger (97 kg) was fed into the hydraulic press for dewatering: and 75% of water is removed in this step. Oil is distributed between the solid and liquid phases in the ratio 2:3. The cake (13 kg) and the juice (81 kg) oil were recovered separately by steam distillation and simple distillation respectively. 62% of the oil present could be recovered from the solid and 70% could be recovered from the juice. The spent cake after distillation contained 74% moisture. This powder was directly used for oleoresin extraction using ethylene dichloride as solvent with a material solvent ratio of 1:5. Oleoresin yield of 0.9% could be obtained by this method. The solvent extracts after desolventisation by distillation under vacuum followed by removing the traces of solvent in thin film evaporator is mixed with the combined oil from cake and juice to get the total oleoresin. The overall yield of essential oil in the process is 0.35% and that of oleoresin 0.9% based on fresh ginger. The figures represent 70% of oil recovery in the pilot plant and 80% of oleoresin recovery. Example 2 98 kg of freshly harvested ginger rhizomes of 83% moisture and 0.5% essential oil were cleaned and subjected to size reduction using a pin mill. The crushed ginger (95 kg) was fed into a screw press for dewatering. 90% water is removed in this step. Oil is distributed between the solid and liquid phases in the ratio 2:5. The cake (9.5 kg) and the juice (83 kg) were distilled separately by steam distillation and simple distillation respectively. 75% of the oil could be recovered from the juice and 73% from, the cake. The spent cake after distillation contained 71% moisture. This powder was directly used for oleoresin extraction using ethylene di chloride as solvent with a material solvent ratio of 1:5. Oleoresin yield of 1% could be obtained by this method. The solvent extractives after desolventisation by the method mentioned in the above example was mixed with the combined oil from cake and juice to get the total oleoresin. The overall yield of essential oil in the process is 0.39% and that of oleoresin 1% based on fresh ginger. The data represents 78% of oil recovery and 85% of oleoresin recovery. Example 3 50 kg of cleaned ginger of 88% moisture and 0.55% essential oil were ground to a paste in a grinder and subjected to dewatering by a hand press. 84% water is removed and oil is distributed between the solid and liquid phases in the ratio 2:4.5. The cake (4 kg) and juice (44 kg) were subjected to steam distillation and simple distillation. 70% oil recovery from the juice and 76% recovery from the cake were recorded. Oleoresin extraction from spent cake was done using hexane-acetone mixture. Desolventisation was carried out as described in Examples 1&2. The overall yield of essential oil was 0.4% and that of oleoresin 0.8% based on fresh ginger. The data represent 73% of oil recovery and 75% of oleoresin recovery. The cake after distillation can be dried at 55-60°C and used directly as ginger powder for food flavouring purposes wherever the pungency of ginger is desirable. The main advantages of the present invention are: (1) The novel technique is cost-effective for processing fresh ginger into value- added products of oil and oleoresin. (2) Loss in volatile oil content (30-40%) and changes in oil quality during sun-drying of the rhizomes are taken care of in this process since fresh ginger is directly processed for the value-added products. (3) Oil and oleoresin products of fresh ginger obtained by this invention are thus in higher yield and are of superior flavour quality compared to their counterparts available in the market. (4) Energy saving leads to reduced cost of production in the novel process. (5) Ginger powder, soluble ginger flavour suitable for soft drinks and ginger starch are the useful byproducts obtained in this process . Table I. Physico-chemical characteristics of fresh and drv ginger oils (Table Removed) Table 2. Effect of method of drying on yield and qualirs of ginger oil (Table Removed) We Claim: 1. A novel process for the production of oil and oleoresin from fresh ginger rhizomes {Zingiber officinale Roscoe.) which comprises preparing paste of cleaned fresh ginger by conventional methods, substantial dewatering of the ginger paste by applying conventional pressure technique to get aqueous phase and solid cake, recovery of oil from aqueous phase and solid cake separately by the conventional distillation methods retaining the frill fresh flavour of ginger, combining the oil obtained from both the phases to get the total oil extracting the cake residue obtained after distillation with permitted organic solvents. Followed by desolventisation by known methods and finally by blending the oil and solvent extractives to get the oleoresin. 2. A process as claimed in claim 1 wherein the size reduction is effected by grinding or crushing in a suitable grinder or mill. 3. A process as claimed in claims 1-2 wherein the substantial removal of moisture is effected either by screw press, hydraulic press, hand press or any other suitable pressing machine. 4. A process as claimed in claims 1-3 wherein the separation of solid and liquid phases of the aqueous portion is effected either by centrifugation or filtration. 5. A process as claimed in claims 1-4 wherein the essential oil recovery from the liquid and solid phases is effected by simple distillation, hydro distillation or steam distillation. 6. A process as claimed in claims 1-5 wherein the solvent extraction of wet or dried solid is effected suing organic solvents such as ethyl alcohol, ethylene dichloride or acetone-hexane mixture. 7. A novel process for the production of oil and oleoresin from fresh ginger rhizomes substantially as herein described with reference to the examples.

Documents:

44-del-2001-abstract.pdf

44-del-2001-claims.pdf

44-del-2001-complete specification (granted).pdf

44-del-2001-correspondence-others.pdf

44-del-2001-correspondence-po.pdf

44-del-2001-description (complete).pdf

44-del-2001-form-1.pdf

44-del-2001-form-2.pdf

44-del-2001-form-4.pdf