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Title:
EXTRACTION METHOD FOR ORGANIC CERTIFIABLE STEVIOSIDES FROM ORGANIC STEVIA LEAVES
Document Type and Number:
WIPO Patent Application WO/2014/097319
Kind Code:
A1
Abstract:
The present invention relates to the stevioside extraction method for an organic stevia leaves which is used as natural sweeteners. More specifically, the present invention relates to solvent free extraction method for providing organic steviosides from organic stevia leaves powder. This method used water as extraction medium for stevioside from dry leaf powder.

Inventors:
SEVAK NIRAVKUMAR PRAKASHBHAI (IN)
DOSHI DR HIREN VINODBHAI (IN)
SHAH DATTESH DILIPKUMAR (IN)
BHATT MAUNIK BHARATBHAI (IN)
Application Number:
PCT/IN2013/000785
Publication Date:
June 26, 2014
Filing Date:
December 23, 2013
Export Citation:
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Assignee:
SEVAK NIRAVKUMAR PRAKASHBHAI (IN)
International Classes:
B01D15/04; B01D11/02
Domestic Patent References:
WO2012006742A12012-01-19
Foreign References:
RU2198548C12003-02-20
US20110091617A12011-04-21
US3446731A1969-05-27
US20060142555A12006-06-29
US5972120A1999-10-26
CA2185496A11998-03-14
JPS5942862A1984-03-09
US20060134292A12006-06-22
CN101798329A2010-08-11
Other References:
AHMARUZZAMAN M ET AL.: "A review on the utilization of fly ash", PROGRESS IN ENERGY AND COMBUSTION SCIENCE AN INTERNATIONAL REVIEW JOURNAL, vol. 36, no. ISSUE, June 2010 (2010-06-01), pages 307 - 374
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Claims:
EXTRACTION METHOD FOR ORGANIC CERTIFIABLE STEVIOSIDES FROM ORGANIC STEVIA LEAVES consists with following steps

organic dry stevia leaves of 1mm or below powder is selected;

three times water decoction process is applied by hot water;

micro-filtration is applied in the sequence of strainer filter, bag filter and cartridge filter;

after filtration solid waste is generated and liquid is passed to further processing;

liquid concentration by water evaporation is carried out gives water recovery up to 50-60%;

sequential coagulation is applied to remove impurities in form of the soluble compunds such as plant pigments, saponins, tannins, sterols , flavoniods, various phenolic compounds, heavy metals. This coagulatiori is proceed in this manner:

1 - Treatment of primary coagulants:

Treatment of flyash

Treatment of calcium hydroxide or calcium oxide

2- Treatment of coagulant aids such as Activated alumina(aluminium oxide);

micro filtration is applied to fly ash treated liquid is 25-35o C then floes are removed with strainer filter (50-500) um, bag filter (10-50) um, cartridge filter (l-lO)um;

filtrate is treated calcium hydroxide or calcium oxide and stirred well for 30 min and 25-35o C temperature then floes are removed with strainer filter(50-500) um, bag filter (10-50) um, cartridge filter (l-lO)um; Calcium activation process:

Solid waste generated from coagulation of crude concentrated extract with calcium compounds, in this process solids are flushed with strong acid which is normally sulfuric acid and then water and then neutralized with strong base which is normally sodium hydroxide then dried and recycle back in the coagulation process. again filtrate is treated with coagulant aid -aluminum oxide and stirred well for 30 min and 25-35o C temperature then floes are removed with strainer filter(50-500) um, bag filter (10-50) um, cartridge filter (l-lO)um; alumina activation process: Solid waste which is generated from coagulation reaction of Activated alumina and filtrate collected after Alteration of calcium treated liquid, this solid waste is regenerated is accomplished through a sequence of rinsing with regenerant, flushing with water, and neutralizing with acid, then regenerant is a strong base, typically sodium hydroxide; the neutralizer is a strong acid, typically sulfuric acid.

depigmentation process is done by activated carbon filter process;

then nano filtration is applied for purification and concentration of stevisides from whole stevioside extract.

the liquid is passed from the ion-exchange process for removal of charged ions from concentrated liquid.

after this, the liquid- liquid extraction of deionised liquid with n-butanol is processed. Two phase (i.e. feed phase and solvent phase) are seperated out by mixing and settling , Organic phase is then seperated by removing water phase, stevioside are crystallized by n- butanol and then it can be separated from the extract phase by vacuum distillation and the solvent is regenerated;

the filtered extract is subjected to spray drying with a high pressure pump at a controlled feed rate and temperature to get dry powder ;

fine powder is put under sterilization before sterile packaging in decanted environment around 90-100°C for 1 hour.

EXTRACTION METHOD FOR ORGANIC CERTIFIABLE STEVIOSIDES FROM ORGANIC STEVIA LEAVES as claimed in claim 1 wherein the water decoction process solid: liquid ration is selected from 1:3 to 1:20.

EXTRACTIO METHOD FOR ORGANIC CERTIFIABLE STEVIOSIDES FROM ORGANIC STEVIA LEAVES as claimed in claim 1 wherein the water decoction process temperature range from 50- 90 o C for 1-3 hrs.

EXTRACTION METHOD FOR ORGANIC CERTIFIABLE STEVIOSIDES FROM ORGANIC STEVIA LEAVES as claimed in claim 1 wherein solid waste is filtered by micro filtration which convert into nitrogen containing byproduct fertilizer by microbial degradation with cellulolytic fungi and decomposition bacteria

EXTRACTION METHOD FOR ORGANIC CERTIFIABLE STEVIOSIDES FROM ORGANIC STEVIA LEAVES as claimed in claim 1 wherein Flyash and calcium hydroxide or calcium oxide are used as primary coagulants.

6. EXTRACTION METHOD FOR ORGANIC CERTIFIABLE STEVIOSIDES FROM ORGANIC STEVIA LEAVES as claimed in claim 1 wherein activated alumina(aluminum oxide) is used as heavy metal scavanger, pigment removal and coagulant aid.

7 EXTRACTION METHOD FOR ORGANIC CERTIFIABLE STEVIOSIDES FROM ORGANIC STEVIA LEAVES as claimed in claim 1 wherein solid from strainer filter and bag filter are collected and added into effluent treatment plant.

8. EXTRACTION METHOD FOR ORGANIC CERTIFIABLE STEVIOSIDES FROM ORGANIC STEVIA LEAVES as claimed in claim 1 wherein solid from strained filter and bag filter are collected and aded into aluminum activation process.

9. EXTRACTION METHOD FOR ORGANIC CERTIFIABLE STEVIOSIDES FROM ORGANIC STEVIA LEAVES as claimed in claim 1 wherein in the calcium activation process, precipitant from the coagulation reaction with calcium hydroxide or calcium oxide is collected and hot water is added to them by mixing mechanical stirring for 1 hrs.

10. EXTRACTION METHOD FOR ORGANIC CERTIFIABLE STEVIOSIDES FROM ORGANIC STEVIA LEAVES as claimed in claim 1 wherein 700-1000 molecular weight cut off nano filtration membranes is used to make steviosides concentrate.

Description:
FIELD OF THE INVENTION

The present invention relates to the stevioside extraction method for an organic stevia leaves which is used as natural sweeteners. More specifically, the present invention relates to solvent free extraction method for providing organic steviosides from organic stevia leaves powder. This method used water as extraction medium for stevioside from dry leaf powder.

BACKGROUND OF THE INVENTION

Presently there are different methods for stevioside extraction are available , some method involve non-organic stevia dry leaves as raw-materials. Chemical fertilizer and various hazardous chemicals which are used as plant protection activity for. stevia cultivation. Various studies have shown that molecular traces of these pesticides and chemicals are present on surface of leaves. These are not easy removable chemicals by simple water washing process. Presence of these chemicals in process may increase heavy metal contamination in stevioside. Organic stevia leaves don't have such problem.

Sweeteners are widely used both by consumers and hy the food and beverage industry. Consumers use them^as an ingredient in various food items and also as a means for customizing the sweetness of beverages, fruit, yogurt, and the like. The food and beverage industry uses such sweeteners in prepared beverages and other food items. Such sweeteners include both caloric and low-caloric sweeteners. Caloric sweeteners include sucrose, fructose, and glucose. Recently, low-calorie (or non-calorie) sweeteners have gained increased popularity. In many instances, they can be used as substitutes for caloric sweeteners and are often referred to as "sugar substitutes". Common sugar substitutes include saccharin, aspartame, and sucralose. In parts of Asia, compounds extracted from stevia plants have also been used as sugar substitutes due to their sweetness potential better than sugar and non-caloric nature.

Object of the Invention

Main primary objective of the present invention is to use environment friendly process which is term as GREEN ORGANIC STEVIOSIDE EXTRACTION which uses minimum chemicals and generating minimum biowaste and chemical waste. In the present invented method 1mm or below size organic stevia leaves fine powder particles are selected so, the surface area increases which leads to effective primary extraction of stevioside from leaf cell to water and powder form of leaves give better particle suspension in water. This will help in efficient mixing and effective agitation at industrial scale.

Some method involve non-organic stevia dry leaves as raw-materials. Chemical fertilizer and various hazardous chemicals which are used as plant protection activity for stevia cultivation. Various studies have shown that molecular traces of these pesticides and chemicals are present on surface of leaves. These are not easy removable chemicals by simple water washing process. Presence of these chemicals in process may increase heavy metal contamination in stevioside. Organic stevia leaves don't have such problem.

In the present invented method three times water decoction process is carried out for primary extraction. Because stevioside has proved to be best soluble in water. In the present invented method after Alteration process, solid waste is generated, which is byproduct of the present invented method. In this process, two type of solid waste is generated:

1 : Bio-waste

2: Chemical waste with coagulated biomolecules. Waste processing is carried out which create environment friendly byproducts which has also economic value. Moist Bio-waste (Stevia dry leaves powder) is generated in heavy amount. And chemical waste from coagulation reaction is generated which has bio-molecules which are precipitated. This bio-solid waste is low moist bio-material. Microbial degradation with cellulosic fungi and decomposing bacteria convert this waste into valuable nitrogen containing byproduct. Because this waste can be considered as green material having very low C:N ratio.

And in chemical waste with coagulated biomolecules, various proteins, carbohydrates, flavonoids, fatty-acids, alkaloids, tannins, pigments, and sterols are precipitated out by sequential coagulation with flyash, calcium oxide or calcium hydroxide, and then activated alumina. These biomolecules can be seperated out from these waste and calcium compounds and alumina can be regenerated. This chemical reactivation process recycles pure calcium compounds and activated alumina. This activation process gives stevioside extraction lesser waste generation capacity than any other extraction process. Lesser chemical waste generation than any other process.

In the present invented method liquid concentration is carried out in various steps gives water recovery upto 40-70%. This is carried out by water evaporation under vacuum.

Detailed Description

The present invention is described in more details clearly with reference to following figures, which illustrates a preferred embodiment of the present invention and wherein,

Figure 1. Structures of steviol and the steviol glucosides.

Figure 2. represents the flow chart of the present invention Exemplary embodiments of the invention are discussed in detail below while specific exemplary embodiments are discussed, it should be understood that this is done for illustration purpose only. A person skilled in the relevant art will recognize that other components and configuration can be used without parting from the spirit and scope of the invention.

Details description of drawings

In the Fig.1 Structures of steviol and the steviol glucosides is shown and in the Fig.2, flow chart of the present invented process is explained. First the Organic dry stevia leaves are selected for this processing. Pulverization of dry leaves of organic stevia gives fine powder of various particle ranges. From this, only 1mm or . below powder is separated by 1mm sieve so, the surface area increases which leads to effective primary extraction of stevioside from leaf cell to water. Powder form of leaves give better particle suspension in water. This will help in efficient mixing and effective agitation at industrial scale.

In the water decoction process, Stevioside is water soluble and its solubility is 1 gm in 10.2ml. Water is best to use in this extraction process. Hot water with proper agitation loosen the cell wall of stevia dry leaf, this will give the maximum solubility of stevioside from leaf to water, solid: liquid ratio is selected from 1:3 to 1:20. Process temperature ranges from 50-90°C. Agitation time ranges from 1-3 hrs. Three times water decoction by recycling the solid waste after filtration gives maximum stevioside from leaves powder.

Then the micro-filtration is selected as filtration process. In this step liquid is passing from three different filters having different filter size. Filtration sequence is as follows

□ Strainer filter(50-500um)

□ Bag filter(10-50um)

□ Cartridge filter( 1 - 1 Oum) After filtration process, solid waste is generated. Liquid is passed to further processing. This solid waste is now moist bio-material. Microbial degradation with cellulosic fungi and decomposting bacteria convert this waste into valuable nitrogen containing byproduct. This waste can be considered as green material having very low C:N ratio.

Then liquid concentration is carried out for water recovery upto 40-70%. This water is distilled by process. This step is carried out by concentration by evaporation process. This concentration step can give various concentration of stevioside in liquid for further purification. Another benefit of this step is volume reduction in further processing and also reduction in volume handling cost.

Then the sequential coagulation reaction is applied, in the first step of coagulation, water decoction treatment gives not only stevioside in water but also various other water soluble compounds such as plant pigments, carbohydrates, saponins, tannins, sterols, flavonoids, various phenolic compounds. These are the impurities which need to be removed. These are dissolved materials which cannot be removed from simple filtration. For removal, first they have to be in insoluble form and for this coagulation and flocculation reaction are done to convert this soluble material into insoluble form. For it several chemicals are used known as coagulants and flocculants. Coagulation process is used to remove dissolved particles of flavonoids, phenols, tannins and proteins other water soluble and polar molecules. Coagulant chemicals come in two main types - primary coagulants and coagulant aids. Primary coagulants neutralize the electrical charges of dissolved particles in the water extract, which causes the particles to clump together. Eg, Calcium containing compounds (Fly ash, calcium hydroxide, calcium oxide)

Coagulant aids add density to slow-settling floes and add toughness to the floes so that they , will not break up during the mixing and settling processes. Eg.Activated alumina(Aluminium oxide). Also activated alumina is effective in pigments removal and heavy metal removal by adsorption process.

Primary coagulants are always used in the coagulation/flocculation process. Coagulant aids, in contrast, are not always required and are generally used to reduce flocculation time.

1: primary coagulants:

Flyash: Fly ash is a kind of waste discharged out of coal-fired thermal power plants. Flyash composition: Si02 ,A1203, Fe203, CaO ,MgO and others.

According to various studies, 40% of flyash composition comprises of trivalent oxides of aluminium and ferric. Also due to presence of various salts of calcium, aluminium silicon and magnesium flyash has the best ability to remove phenols, pigments, flavonoids and tannins and heavymetals such as chromium,cadmium, mercury,zinc,copper,nickle. Alumina present in this flyash form chemisorptions linkage with these heavy metals. Calcium compounds present in flyash leads to change the charge of organic compounds such as proteins and precipitate out them.

Calcium hydroxide and calcium oxide: calcium oxide or calcium hydroxide increases the pH of the solution. So the net-charge distribution changes and neutralizes the electrical charges of the dissolved particles. This will cause the floe formation, so that effective filtration can remove it.

2: coagulants aids: Activated alumina(Aluminium oxide) is mainly used as pigment removal and coagulant aid. Aluminium is trivalent ion which replaces the Magnesium ions in chlorophyll and other metaloprotein complex. This will change the net-charge of the complex, thus it will affect the polarity of the complex. So solubility of the complex is changed. And chlorophyll and proteins are precipitated out into the solution which can be filtered out. Then the micro- filteration, first Flyash treated liquid is stirred at 25-35°C temperature and then filtered with strainer filter(50-500)um, bag fllter(10- 0)um and cartridge filter(l- 10)um. Solids from strainer filter and bag filter are collected and added into effluent treatment plant. Then filtrate is treated with calcium oxide or calcium hydroxide and stirred at 25-35°C temperature. Then floes are removed with strainer filter(50-500)um, bag fllter(10-50) um and cartridge filter(l-10)um. Solids from strainer filter and bag filter are collected and added into Calcium activation process.

Again filtrate is treated with coagulant aid-Activated alumina (aluminium oxide), and stirred well for 30 min at 25-35°C temperature. Then floes are removed with strainer filter(50-500)um, bag filter( 10-50)um and cartridge filter(l-10)um. Solids from strainer filter and bag filter are collected and added into Calcium and Aluminium activation process.

Calcium activation process, precipitants from the coagulation reaction with calcium hydroxide OR calcium oxide is collected and hot water is added to them. Mixing by mechanical stirring is carried out for 1 hr. then water is removed by filtration and the solids are heated for drying. Then regeneration treatment with acid- water-base is given to the solids and then calcium compounds are heated for drying and then recycled back for coagulation reactions.

In the Alumina activation process, Activativation of Alumina (AA) is a physical/chemical process by which ions in the feed water are sorbed to the oxidized AA surface. AA is considered an adsorption process, although the chemical reactions involved are actually an exchange of ions (AWWA, 1990). Activated alumina is prepared through dehydration of Al(OH)3 at high temperatures, and consists of amorphous and gamma alumina oxide. Activated Alumina is used in packed beds to remove contaminants such as fluoride, arsenic, selenium, silica. Feed water is continuously passed through the bed to remove contaminants. The contaminant ions are exchanged with the surface hydroxides on the alumina. When adsorption sites on the Activated alumina surface become filled, the bed must be regenerated. Regeneration is accomplished through a sequence of rinsing with regenerant, flushing with water, and neutralizing with acid. The regenerant is a strong base, typically sodium hydroxide; the neutralizer is a strong acid, typically sulfuric acid. Then in the Activated carbon filter, depigmentation process is done by activated carbon filter. It plays dual role in plant extraction process.

The merits of activated carbon for removal of organic compound from water have been well documented in the literature, but the potential for adsorption of inorganic compound has receive little publicity in water field literature so this concept is used for adsorption of inorganic compound such as arsenic, cadmium, selenium, fluoride, chromium etc. in plant extraction process.

Also activated carbon has a virtually non-polar surface where as polymeric adsorbents have a polarity. The colourants are basically hydrophobic(not highly soluble in water) and will tend to adsorbed on hydrophobic part of the adsorption media .This is a main mechanism in colour removal.

Then, nanofiltration (NF) membranes are a relatively recent development in the field of pressure-driven membrane separations, and their properties lie between ultrafiltration (UF) and reverse osmosis (RO).

The transportation of non-charged solutes through an NF membrane is usually characterized by the term of molecular weight cut-off (MWCO), which is a number expressed in Dalton indicating the molecular weight of a hypothetical non-charged solute that is in 90% rejected so, this principle is used for separation of stevioside from whole plant extract. Thus with the help of this nano-filteration concentration of steviosides is carried out. Here reject is the steviosides concentrate and permeate is water and little amount impurities which can be easily recollected. So reject is used for further processing, the concentration of reject is varies by change in pressure, process temperature and time for filteration. 700-1000 MWCO is used to make steviosides concentrate. This range is useful for removal of bitter taste compounds from stevioside extract.

After nonofilteration, Ion-exchange processs is applied where Ion exchange (IX) is a physical/chemical process by which an ion on the solid phase is exchanged for an ion in the feed water. This solid phase is typically a synthetic resin which has been chosen to preferentially adsorb the particular contaminant of concern. To accomplish this exchange of ions, feed water is continuously passed through a bed of ion exchange resin beads in a downflow or upflow mode until the resin is exhausted. Exhaustion occurs when all sites on the resin beads have been filled by contaminant ions. At this point, the bed is regenerated by rinsing the IX column with a regenerarit - a concentrated solution of ions initially exchanged from the resin. The number of bed volumes that can be treated before exhaustion varies with resin type and influent water quality. Important considerations in the applicability of the IX process for removal of a contaminant include water quality parameters such as pH, competing ions, resin type, alkalinity, and influent arsenic concentration. After ion exchange Liquid-Liquid Separation and crystallization, The plant extract(Feed phase) contains a component stevioside which is to be removed. Addition of a second phase (solvent phase) which is immiscible like n-butanol with feed phase but component stevioside is soluble in both phases. Then steviosides (solute) are transferred from the feed phase to the solvent phase. After extraction the feed and solvent phases are called the raffmate (R) and extract (E)

phases respectively. After the extraction the two phases can be separated because of their immiscibility. Then the steviosides are crystallised by distilling n-butanol and then it can be separated from the extract phase by vacpum distillation and the solvent is regenerated After that Spray drying is applied, which filtered extract is subjected to spray drying with a high pressure pump at a controlled feed rate and temperature, to get dry powder. The desired particle size of the product is obtained by controlling the inside temperature of the chamber and by varying the pressure of the pump. And finally at last Sterilization process, fine powder is put under sterilization before sterile packaging in decanted environment around 90- 100°C for 1 hr. this will prevent moisture and bacterial and any other contamination in final product.

While, the invention has been described with respect to the given embodiment, it will be appreciated that many variations, modifications and other applications of the invention may be made. However, it is to be expressly understood that such modifications and adaptations are within the scope of the present invention, as set forth in the following claims.