K. V. GOPALAIYAR and K. CHIRANJIVI RAO Sugarcane Breeding Institute, Coimbatore

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1 STUDIES ON THE RELATION OF THE CHEMICAL COMPOSITION OF CANE JUICES AND THE QUALITY OF JAGGERY WITH SPECIAL REFERENCE TO THE NEW CO. CANES K. V. GOPALAIYAR and K. CHIRANJIVI RAO Sugarcane Breeding Institute, Coimbatore "Gur" or Indian Sugar, which is the product obtained by concentrating sugarcane juices with or without the addition of clarificants into solid or semi-solid state, occupies a very prominent place in the sugar industry of India. Even with the phenomenal development of the white sugar industry, the importance and the production of "Gur" has not been reduced in any way. The total production of "Gur" in India is about 2 times that of crystal sugar. "Gur"-making is one of the most important cottage industries in India. The quality of "Gur" varies widely. The characteristics of good quality "Gur" are light colour, good flavour, hardness, good crystalline structure and good keeping quality, though the emphasis laid on the different characters varies from place to place. The quality of "Gur" depends mainly on the quality and the chemical composition of the cane juice, though the quality may be further modified by the method of boiling and the clarificants used for purifying. Good "Guru-making quality is the sinequa-non of a successful and popular cane variety. In the selection of improved cane varieties at the Sugarcane Breeding Institute, along with the agronomical and chemical characters, the gur-making quality is also taken into consideration. The 1958 batch of Co. canes comprises 42 new varieties, Co. I232 to Co. 1273, selected to suit the various cane tracts in India. The chemical composition of these cane varieties, as well as the physical and chemical characteristics of the "Gur" produced from them, have been studied. Much work has been done in India and elsewhere on the relation between the chemical composition of cane juice and the quality of "Gur". But still there are considerable lacunae in our knowledge of the effect of the different constituents of cane juice on the quality of "Gur". The part played by the different non-sugars in the juice on the physical and chemical characteristics of "Gur", is by no means clearly understood VARAHALU~~ in his detailed studies on the physical and chemical characteristics of sugarcane "Gur", or jaggery, observed that all good jaggeries have high purities, low glucose and glucose ratios and low amounts of organic non-sugars. KHANNA~ observed that good jaggeries are characterised by light colour, open texture, high sucrose and low glucose content. Observations of SANYAL~ indicate that nitrogenous manures applied to cane adversely affect juice quality, while phosphoric and potassic manures improve juice quality. SATYANARAYANA~ observed that the non-protein nitrogen as well as total nitrogen, has an adverse effect on juice quality. Exhaustive studies of juice quality have been made by KHANNA and CHAXRAVARTI~. They attribute good quality in juices to low levels of colloids, gums, pectins and ash, and to high phosphate. Though differences in good and poor quality juices were not significant, there was a preponderance of non-protein nitrogen in the poor quality juices Observations of MOHAN RAO~ also reveal the association of poor quality juice with high organic non-sugars, high total and non-protein nitrogen, high colloids and low amounts of phosphate.

2 TABLE I PARENTAGE OF NEW CO. CANES AND COMPOSITION OF JUICES - Total Albu- Tannins Sl. Co. Brix Sucrose True Reducing Fibre Colloids Nitro- mznotd G colour- C.C.S. Co No. No. Parentage % Purity sucrose sugars ash gen- Nitrogen zng matter I CO. 419 G.C Co. 464 x Co CO. 419 X K Co x K Co. 527 x co CO. 866 x Co co. 780 x co I239 Co. 780 x Co CO. 780 X CO. 28j Co. 726 x Co CO. 726 x Co Co. 677 x P.O.J Co. 677 x P.O.J o Co. 658 x Q. jo Co. 650 x Co Co. 780 x Co ; 1248 Co. 419 x K Co. 270 x S. spont. Cbe bj j0 CO. 726 x CO G x K. 98 (Co. 421 x Co. 649) G X Ii Co. 678 x Co CO. 678 X CO Co. 678 x Co Co. 419 x Q Co. 475 x Co I Co. 780 x Co CO. 677 x P.O.J Co. 312 x Co. L. g Co. 464 x C.P. 49/ C.P x Co Co. 270 x Co Co. 603 x P (Co. 449 x P. 63/32) (P.O. J x Alang Alang) CO. 678 x CO CO. 60j x P Co. 578 x Co Co. 677 x Co Co. 801 x Co P x P (CO. 331 X SW. 111) Co. 995 X Co Co. 677 x Co Co. 527 x Co

3 TABLE I1 PHYSICAL AND CHEMICAL CHARACTERISTICS OF JAGGERY FROM NEW CO. CANES Hard Black Soft Hard Hard Hard Red Hard Yellowish brown Soft Yellow Very soft Red Hard Soft r, Hard Yellow Hard Hard Black % Hard Deep brown I 3.85, Hard Light brown Hard Hard ' I Hard Hard Hard Hard Hard Hard Reddishbrown Hard Reddishbrown ~j j Hard - - Hard Reddish brown Hard Reddishbrown Hard Jaggery not prepared Hard Reddish brown Hard Dark brown Hard - - Hard Llght brown Hard Hard Dark brown Hard Red&shbrown Hard Hard Reddish brown Soft Black Hard Dark brown Hard Black v Hard Reddishbrown

4 828 BREEDING I It has been suggested that reaction between reducing sugars and nitrogen compounds affects the colour and quality of "Gur". Different nitrogen fractions and ash constituents have also been found to influence the quality of "G~r"7~~~~. Although ZERBAN~~~ l3 showed that the tannin in sugarcane juice forms blue green pigments with iron, VISWANATH~~ found no relation between tannin content of juice and colour of "Gur". JATICAR~ reviewed the effect of iron on sugar colours and concluded that colouration of "Gur" was more due to iron content and the formation of deeply coloured compounds with tannins than to caramelization. Jaggery was made from all the new Co. varieties of 1958 with the exception of Co The varieties were grown under similar soil, rnanurial and cultural conditions. About 75 Ibs, of juice from each variety was placed in a small shallow iron pan and the juice neutralised with milkc of lime to a p~ of 6.4 to 6.8. Scrupulous removal of scum was made by means of a ladle with wire gauze cover until the temperature of the juice reached 105" C. The charge was heated carefully and uniformly from the time the juice reached a temperature of 105" C until the 'Strike point". The pan was then removed from the fire, allowed to cool, and when the mass showed signs of proper crystal formation, it was pressed into wooden moulds. When the cubes had cooled sufficiently, they were removed from the moulds. The juice from each variety was analysed for brix, pol., reducing sugars, ash, colloids, total nitrogen, protein nitrogen, tannin, colouring matter, and p ~ The. results of analysis are in Table I. Juice from most of the varieties produced hard jaggery with light colour, open texture, and high sucrose. The inferior jaggery obtained from certain varieties may be attributed to lack of maintenance of correct p~ of the juice or to the drought experienced late in the crop and the consequent deterioration of the cane. The physical characteristics of the jaggery such as colour and hardness were noted. The results of analysis for brix, pol, reducing sugar, ash, pore space, moisture and moisture absorption at 75% relative humidity are given in Table 11. The colour of the juice for each variety was determined on a HILGER photo-electric calorimeter. JAGGERY-MAKING QUALITIES OF THE NEW CO. SEEDLINGS 1 In general, most of the varieties gave hard and crystalline jaggery. The best jaggery with low colour value, good structure and high pore space, was obtained from Co The high values for colour index for some of the varieties are mainly due to excess of lime that was used for clarification. The optimum p~ of limed juice for a good quality jaggery is about 6.4 to 6.7. A preliminary study indicates that good jaggeries are obtained from juices with low amino acid nitrogen. Considerable variation in the strike point temperature and the time of cooling in setting is also noted. In case of good jaggeries, the time talcen before setting is comparatively small. ACKNOWLEDGEMENT Thanks are due to SHRI N. L. DUTT, former Director, and Dr. N. R. BHAT, Director, Sugarcane Breeding Institute, Coimbatore for affording all facilities.

5 R. A. AGARWAL, P. A. ICANDASWAMY 829 REFERENCES 1 JATKAR, S. K K. et al., Proc. 10th Ann. Conven. Deccan Sugar Tech Assoc. P KHANNA, K. L, 1942 Agr. J. Indtu. 3 KHANNA, K. L. and CHAICRAVARTI, A. S., The non-sugars In sugarcane jusce and their bearing on clarifying properties-a study in relation to open pan industry. 4 MOHAN RAO, N. V., Proc. Ijzrst Bienn. Conf. of Sug. Res and Dev. Workers, Pt. 11-1, Jan SANYAL, P. B., Agr. J. Indzu. 23 : SATYANARAYANA, Report of the Scheme for Research on the Chemistry of sugarcane, Ind. Agr., Res. Instt., New Delhi. 7 SATYANARAYANA, Proc. ~ 1st Ann. Conven. Sug. Tech. Assoc. India, p SCHNEIDEN, et al, Sugar, 48, 48 (Abstract). 0 TEMBHEKAR, V. V., Proc, 11th Ann. Conv. Deccan Sugar Tech. Assoc., p VARAHALU, T., Thesis for the M.Sc. degree of the Madras University. 11 VISWANATHAN, Annual Report of the Scheme for Research on the Chemistry of sugarcane at the Ind. Agr. Res. Instt., New Delhi. 12 ZERBAN, F. W., Ind. Eng. Chem., 10, p ZERBAN, F. W., Ind. Eng. Chem., 11, p DIFFERENTIAL IN JURY TO SUGARCANE BY GRASSHOPPERS (GASTRIMARCUS MARMORATUS THU.) R. A. AGARWAL and P. A. KANDASWAMY Sugarcane Breeding Institute, Coimbatore INTRODUCTION Grasshoppers have often caused concern as a serious pest of vegetation. The damage is done both by the young and adults. There are nearly roo species of grasshoppers infesting sugarcane in different parts of the world. In India, 17 species are known to occur. Grasshopper incidence on sugarcane was noticed by the authors during May Varieties displayed wide differences in susceptibility to damage by these insects. Certain varieties were almost completely defoliated, whereas others in the same plot showed little or no injury. The most striking contrast was observed between varieties with dark and light coloured leaves. Variations in the intensity of attack by grasshoppers on species of graminaceous crops like corn, sorghum and seedling grasses, and on dent and flint corn have been reported. Much experimental work has been done on the reactions of insects to light and colour. Like human beings, insects can distinguish between many colours and in addition can perceive certain ultraviolet rays in colour form. PAINTER^^ observed that t'he behaviour of insects was related to the different physical attributes of light: viz., direction, intensity, wave length and colour, and, in some cases, the direction of the oscillatiolls of polarised light. ISELY~~ found red-leaved cotton to be more resistant to boll weevil than green-leaved varieties. The yellow-green varieties of peas were more resistant to the pea-aphid than the blue-green varietiess4> 4. FLEMING et al6 concluded that the Japanese beetle was able to discern and avoid obstacles from some colours better than others. ISLE~O observed that the females of Pieris brassicae (LINN) pre-