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Phytochemistry |
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Dr. G. I. Khan || Dr. Swadesh
Malhotra
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Ms. Gohar I. Khan
Scientist E II
| Phone no. 91-522-2205831-35 Ext. 910 | gi.khan@nbri.res.in |
Dr. Mahesh Pal
Scientist C
| Phone no. 91-522-2205831-35 Ext. 912 | m.pal@nbri.res.in |
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Group works on
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The gums chemistry activity involved in R and D on seed gums, Exudates gum and Resins
from Non wood forest products. The group is involved in R & D work on seed gums
and other natural polysaccharides from existing and new sources with special reference
to their physico-chemical, structural, X-ray diffraction, rheological, interaction
and modification studies. Besides biopolymers, the group is engaged in development
of extraction profiles of natural dyes from existing and new sources and their application
work for coloring fibers, cosmetics, herbal formulations, food etc. The gums activity
group is involved in R & D of eco-friendly, non-toxic, low cost and abundantly
avaliable. Non wood forest products, seed gums, Exudate gums and Resins.
These Polysaccharides from existing and new sources are subjected for their Physico-chemical,
Structural (Isolation, sugars detection, Methylation, per iodate oxidation, oligosaccharide
determination), Rheology, Viscosity and Interaction, studies , 13 C- NMR studies,
X-Ray diffraction, HPLC and Modification by different derivatives and molecular
weight determination for their applications in various important industries like
Pharmaceuticals, Food, Cosmetics, Explosives, Toileteries, Paper, Textile, Paints
and Petroleum etc. As these gums are vegetable hydrocolloids they are excellent
additives for various purposes like binding, emulsifying , sizing , stabilizing
, thickening, film- forming, flocculating and to provide texture to the end products.
The galactomannan is a branched Polysaccharide consisting of the main chain of D-mannose
units linked through b-(1->4) to which are attached
single D-galactose units through α-(1->6)
linkages. Basically these hydrocolloides are water soluble.Because of this water
solubility, they improve mouthfeel and pourability, extend life, encapsulates flavors,
emulsify beverages, build viscosity, retain moisture and provide elasticity and
freeze-thaw stability. The properties of gums for various industrial uses are effected
by many factors such as orientation and molecular association, water binding and
swelling, concentration, particle size, degree of dispersion and interaction with
other gums. Scanning Electron Microscopic Studies (SEM) were used to examine the
characteristic distinct crystalline morphology of some commercial gums at various
magnifications from (x200) to (x6000). Above this magnification decaying of sugar
particles started. The observations recorded have revealed that SEM studies of various
Polysaccharides could be used for finding out the purity of the substance e.g. in
food and medicinal applications.
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Background and Importance of Hydocolloids:
Vegetable gums are important food additives used in food processing. These gums
are the natural food hydrocolloids that possess excellent thickening, binding, emulsifying,
suspending, water-holding, gelling and viscosity properties and used in a variety
of food applications. Some of these are guar gum, gum arabic, gum tragacanth, alginic
acid, carrageenan, locust bean gum etc. Semi synthetic hydrocolloids such as methyl
cellulose, sodium carboxymethyl cellulose, etc. have also been used. NBRI has contributed
significantly on the R and D on vegetable gums and become an important centre in
the country for their application work in industries like food, Pharmaceutical,
cosmetics etc. More than one-thousand seeds have been screened for their water soluble
gums, protein etc from various families. Family leguminosae have been found rich
in gum percentages.
Plants are the main sources of natural gums. India is a rich centre of biodiversity
and offers great potential for the sustainable utilization of these natural resources
by converting plant wealth into economic wealth through biotechnology. Plant gums
yield low to high viscosity depending upon different concentrations and conditions
of time, temperature, pH, shear rate, shear stress etc. and possess excellent thickening
and binding properties that are traped for their Vast Industrial applications.
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Objectives
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- To explore and identify new sources of seed gums from Indian flora, particularly
from Leguminoseae family. Seed gums from the genera like Cassia, Crotalaria, Sesbania,
Caesalpinia, Indigofera, Gleditsia have been studied for their detailed chemical
investigations.
- Exploration of new galactomannan combinations.
- Rheological, structural and interaction studies of seed gums.
- Evaluation of inheriting properties of seed gums and value addition of seed gums
through physical and chemical modification to enhance their properties for their
application in food industry.
- Toxicological and safety trials of gums and gum derivatives.
- Application trials of natural gums for food processing and other industry like Pharmaceutical
and cosmetics for their technical feasibility, extraction processes and processing
technologies.
- Commercial utilization of vegetable gums as food additives for the following reasons:
(i) To maintain product consistency.
(ii) To improve or maintain nutritional value.
(iii) To maintain palatability and wholesomeness.
(iv) To control acidity/alkalinity.
- Seed gums are the preferred hydrocolloids since these are comparatively cheap, non-toxic,
eco-friendly and non polluting during production and application.
- Evaluation of the structure of the molecules by UV, IR, 13C-NMR, Gc-Ms etc.
- Studies of the constituents sugars through PC, TLC, GLC, HPLC and HPTLC etc.
- Modification of the polymer through thermal procedure and chemical derivatization
by the preparation of hydroxyl ethyl, hydorxyl propyl, carboxymethyl and oxidized
derivatives.
- Establishing the use of seed gums specifically cassia species as natural additives
in medical preparations.
- Identification of important resins by certain simple and relevant tests so as to
remove confusion in their identity.
- CMC derivatives of the gum with varying levels of degree of substitution. They showed
good solubility in water.
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Achievements
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- The group has introduced some potential sources of seed gum, which posses useful
non-ionic and solution properties to be utilized for various industrial applications.
It include Dhaincha gum from Sesbania bispinosa and cassis gum
from Cassia tora and Cassia Siamea. These gums have been produced
in India in handsome amount for varied industrial applications and export.
- The group has developed a process for the preparation of Herbal Dry Color Composition
for direct skin applications. The invention relates to the blending of natural dyes
with natural ingredients at specific proportions and conditions. The resultant color
powders thus prepared have good sticking capacity to skin and can be easily removed
by soft mop. The preparation of Herbal-Gulals provides an option/alternative to
replace synthetic dye bases dry powers for Holi playing. The complete specifications
of process are under patenting process at Indian Patent Office.
- Lab Scale Technologies regarding extraction and application of seed gums and natural
dyes is
available, which can be upgraded to large scale, whenever required by any entrepreneur.
- Lab Scale Technologies regarding the preparation of semi-synthetic gums have been
developed.
- The group has generated useful information regarding the availability of numerous
sources of seed gums and their physico-chemical properties, structural aspects,
viscosity behavior and interaction capabilities for the benefit of basic researchers
and industries.
- More than 200 research papers have been published in National and International
journals.
- The group has collaboration with Research Center for Vegetable Macromolecules (CERMAV-CNRS),
Grenoble France for advanced researches on food hydrocolloids.
- Value added processing in valves either chemical modification of the gum or blending
with other gums to produce a final product with a range of physical and functional
properties designed to suit the end users requirements.
- Developmental potential of various Cassia gums like Cassia siamea, C.fistula, Cassia
grandis, C.marginata, Cassia angustifolia through derivatisation like Carboxy methyl
cellulose, Hydroxyethyl cellulose, Hydroxy propyl cellulose and oxidised methods.
- Studies on classification of gums used in food products
- Nonionic seed Polysaccharides - Guar, carob and Tamarind
- Anionic (Negatively charged exudate Polysaccharides - Arabic, Karaya and Tragacanth
- Through study on compatability with various salts like Sodium Chloride, Potassium
Chloride, Aluminium Sulphate and many others.
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Properties of Seed Gums
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- Seed gums are light to dark cream colored amorphous powder characterized by forming
Viscous or clear solutions when dispersed or dissolved in cold or hot water.
- They produce low to high viscosity 100 to 8000 cP depending upon the source and
manufacturing process. They have property of forming high viscosity even at low
concentration (4500-8000 cP at 1% w/v) where cP=centipoise, Measure scale of Viscosity.
- Seed gums are stable over a wide range of pH(3-9). The nonionic nature of the polymer
is responsible for almost constant viscosity of the solution.
- They have excellent compatibility characteristic with organic, inorganic substance
including certain dyes and various constituents of food.
- They shows effective settling (flocculation) properties even at lower concentration.
- They have strong hydrogen bonding properties due to the presence of cis-pair of
hydroxyl groups in the b(1->4) linked main mannan
chain of the polymer. In some cases, it is more preferable than other natural polymer
like starch.
- They behave excellent Surfactants in various cosmetic products with respect to ionic
polysaccharides.
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Resins
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There is a large scale confusion while describing resins. Several samples of market
resins sold under the name of Luban and Kundur and dammar samples under the name
of chundurus and Ral were analysed. The Luban was essentially gum benzoin from styrax
species and not the true olibanum from Boswellia species. However Kundur was the
product of Boswellia Serrata, and therefore could be termed Indian oliba
num. The dammars sold in the Indian market as Ral originated from Shorea
species and those under the name of chundurus originated from Vateria indica
Linn. or some other species of vateria and vatica. A medicinally strong
anti-oxidant resin styrax benzoin. Resin present a great variety of structural
specifications. As potent antioxidant, benzoin is specially important for protection
against human diseases. Gum benzoin is a natural source of benzoic acid and benzoic
acid esters. Gum benzoin is obtained from Syrax benzoin trees indigenous
to Sumatra and Thailand. The resinoid is prepared by
alcoholic extraction of the crude benzoin which is scraped directly from the trees.
At normal use level, it should not impart an odor to the finished product.
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Training Capabilities
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Isolation and various mesh preparations of crude gums. Purification by Barium Carbonate
method and various profiles for pH, shear rate, temperature, concentration and time.
Degradation observations, SEM studies etc. Identification of gum exudates and resins.
Value additions of native gum for new resources, by removing peculiar odour of the
seed, hydration profiles, treatment with sodium hydroxide and other salts to enhance
their capabilities to be used in stages of processes for preparation of final products.
Like in ice cream preparations to slow the melt down process, to increase mouthfeel
and reduction of ice crystals etc. Deformation of solution and their studies through
Rheometer, helipath viscometer etc.
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