The preparation of carboxymethyl (CM)-Cassia tora gum (CTG) with monochloroacetic acid and sodium hydroxide was investigated under different reaction conditions. The carboxymethylation reaction was studied with respect to the degree of substitution of CM-CTG. The variables studied were the concentration of reactants, methanol-water ratio (solvent), reaction time, and reaction temperature. Carboxymethylation of CTG increased its solubil-ity in cold water and the stability of its paste to microorganisms. Regardless of the degree of substitution of these products, their aqueous solutions were characterized by non-Newtonian pseudoplastic behavior. Determination of the rheological properties of CM-CTGThe rheological properties were determined with a Brookfield digital viscometer (model RVTD, Stough-Correspondence to: V. Kumar (vineetkmadan@yahoo.co.in) or P. L. Soni (sonipl@icfre.org).

Starch from the seeds of Quercus leucotrichophora was isolated, purified and its physico‐chemical properties were determined. Scanning electron microscopy of the granules show that they are oval to eliptical in shape. Its has high contents of ash, lipids, proteins and lower content of amylose. Its gelatinization temperature is 80–85°C and displays high water binding capacity. It has low swelling power but high solubility. Amylograph study shows 425 B.U. paste viscosity and no thinning inspite of 3 h heating. On cooling starch retrogrades to paste viscosity of 1200 B.U.

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Graft copolymerization of acrylamide onto Cassia tora gum was studied in an aqueous medium using ceric ammonium nitrate-nitric acid as the redox initiator. To optimize the reaction conditions for obtaining maximum percent grafting, the concentrations of Cassia tora gum, ceric ammonium nitrate, acrylamide, and nitric acid, time, and temperature were varied. Results are discussed and a reaction mechanism is proposed.

ABSTRACT:The seeds of Cassia occidentalis, an annual weed occurring throughout India, are a rich source of galactomannan gum. The gum derived from seed endosperm can be utilized in a number of industries to replace conventional gums. With a view to utilize the gum for broader applications, carboxymethylation of Cassia occidentalis seed gum was carried out. The reaction conditions were optimized with respect to concentration of monochloroacetic acid, sodium hydroxide, solvent ratio, reaction time, and reaction temperature. Rheological studies of carboxymethyl gum exhibited relatively high viscosity and stability vis-a-vis unmodified Cassia occidentalis gum.

Starches frOln the tubers o f Dioscorra hallophylla and A morphophtrl-/us cumpanirlafrt.s were isolated and purified. Scanning electron niicroscopy of these starches exhibits cliptical, spherical or irregular shapes, respectively, while the shape of tapioca is spherical. Waterbinding capacity o f A . cumpanulatiis starch is very high in coniparison to D. ballophylla and tapioca starches but the amylose content is significantly less. Gelatinization temperature of both these starches is the same but it is higher when coinpared to tapioca starch, swelling power and solubilities arc less. Paste viscosity characteristics show high peak viscosity for A . cornpmrrlarus in comparison to D. hallopliyllu and tapioca starch. Die Starken von Dioscorea ballophylla undAmorphophallus campanulatusvergleich mit Tapiokastarke. Die Stlrken der Knollen von Dioscorca ballophylla und Amorphophallus canipanulatus wurden isoliert und gcreinigt. Die Raster-Elektronenmikroskopie dieser Stlrken zeigt clliptische, spharische oder unregelmiiRige Formen, wiihrend die Form von Tapiokastiirke sphlrisch ist. Das Wasserbindungsvermogen der StLrke von A. campanulatus ist sehr hoch im Vergleich zu den Stiirken von D. ballophylla und Tapioka, doch ist der Aniylosegehalt deutlich geringer. Die Verkleisterungsteiiiperatur dcr beiden Stiirken ist gleich, jedoch holier iin Vergleich zu Tapiokastarkc; Quellvermogen und Loslichkeiten sind geringer. Der Viskositiitsverlauf zeigt hohere Spitzenviskositlt bei A. campanulatus ini

The graft copolymerization of acrylonitrile (AN) onto Cassia tora gum (CTG) was carried out in an aqueous medium with a ceric ammonium nitrate (CAN)nitric acid initiation system. The percentage grafting and percentage grafting efficiency were determined as functions of the concentrations of CAN, nitric acid, AN, and CTG and the polymerization temperature and time. The results are discussed, and a reaction mechanism is proposed.

Bamboo, a lignocellulosic biopolymer material, is of interest as feedstock for production of cellulose derivatives by chemical functionalization. Optimization of grafting of acrylonitrile onto cellulosic material (average Degree of Polymerization 816), isolated from bamboo (Dendrocalamus stictus) was performed by varying the process parameters such as duration of soaking of cellulosic material in ceric ammonium nitrate solution, ceric ammonium nitrate concentration, polymerization time, temperature of reaction and acrylonitrile concentration to study their influence on percent grafting and grafting efficiency. Graft copolymerization of acrylonitrile onto cellulosic material derived from bamboo (Dendrocalamus strictus) in heterogenous medium can be initiated effectively with ceric ammonium nitrate. The optimum reaction conditions obtained for grafting of acrylonitrile onto cellulosic material were: duration of dipping cellulosic material in ceric ammonium nitrate solution 1 hr, ceric ammonium nitrate concentration 0.02 M, acrylonitrile concentration 24.6 mol/anhydroglucose unit, temperature of reaction 40°C and polymerization time 4 hrs. The percent grafting for optimized samples is 210.3% and grafting efficiency is 97%. The characterization of the grafted products by means of FTIR and Scanning Electron Microscopy furnished the evidence of grafting of acrylonitrile onto the cellulosic material