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Estimation of colloids in juice and jaggery

Indiscriminate harvest of cane before the attainment of maturity lowered the brix and purity and production of gur and analysis of juice had showed high content of nitrogen and colloids and low content of phosphate, brix and purity. Colloids and non-protein nitrogen are confirmed to be important factors in quantities of juice and gur. Sugarcane juice was a complex product consisting of colloidal substance like melanoidins which needed to be removed. Vegetable clarificants were used to coagulate the colloidal impurities and to remove the suspended particles which form scum on heating and were ladled out. Increasing dose of N brought about a low claribility of juice with poor gur quality and increase in colloidal content of the juice. The adverse effect of application of high dose of nitrogenous fertilizers, however, could be mitigated by the use of suitable clarificants in gur manufacture. Chlorophyll, xanthophylls and carotene are in colloidal form and are easily removed during processing. Lime neutralizes the juice and facilitates flocculation of colloidal material and its removal. Gummy colloidal constituents in juice were removed by coagulation during first heating. Use of lime destroys glucose which helps in coagulation of the irreversible colloids and to some extent reversible colloids. Juice of high sucrose and lower content of invert sugars, free amino acids, colloids and ash were conducive for superior quality gur. Low colloids, low ash, high phosphate, low ash in colloidal matter, low total ash, non-protein N, harmful N, harmful nitrogen per total organic nitrogen, soluble silicon, potassium, iron and aluminium, calcium and magnesium oxide are characteristics of good juice yielding good jaggery. Eleven methods to determine colloids are presented in this paper to identify a rapid and accurate method to estimate colloids in juice, jaggery and sugar

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