Sugarcane is a perishable commodity and must be processed into sugar quickly after it is harvested. Post harvest sucrose losses have been reported from many cane producing countries and linked with low sugar recovery and several problems during sugar processing. Bio deterioration is associated with the inordinate delays between harvest to milling of sugarcane and aggravated by many intrinsic and extrinsic factors causing enormous depreciation in cane tonnage as well as sugar recovery. Besides harvest-to-mill delays, other factors such as ambient temperature, humidity, cane variety, period of storage, activities of invertases, maturity status etc. are responsible for decline in sugar recovery. The activity of invertases and proliferation of acid, ethanol and polysaccharides (dextran) producing microbes play a crucial role in the loss of recoverable sugars in cane and milled juice. In addition to loss in sugar recovery, its adverse affects has been noticed in the sugar manufacturing process and sucrose quality. Efforts have been made to reduce loss in tonnage and sucrose using physico-chemical methods. These include spraying of water, bactericidal solution, use of anti-inversion and anti-bacterial formulations and pre-harvest foliar and soil application of zinc and mangnous compounds. An integrated mill sanitation program and simultaneous use of dextranase could further improve sugar recovery and minimize problems caused by dextran. The possibility of electrolyzed water (EW) fogging to reduce post harvest deterioration in field and mill yard has also been explored. Some of these methods are useful and present larger options for the industry to minimize afterharvest quality losses in the field and milling tandem.

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The present study employed a sand culture experiment with three levels of zinc viz., 0.065 (control), 65.0 and 130 mg l -1 Zn (excess) as zinc sulfate, respectively, in sugarcane (Saccharum spp.), cultivar CoLk 8102. The results indicated growth depression, dark green leaves, decreased root number and length and sharp depression in mitotic activity of roots due to high doses of Zn (65 and 130 mg l -1 ); effects were significant at 130 mg l -1 Zn supply. The endogenous ion contents measurements revealed roots to be the major sink for excess Zn with lower amounts in leaves of sugarcane plants. High level of Zn decreased total phosphorus in leaves and increased it in roots. Fe and Cu content decreased, while, Mn increased in sugarcane plants due to high Zn in the growing medium. Plants experienced oxidative stress when exposed to higher levels of zinc. Biochemical investigations indicated high level of hydrogen peroxide, malondialdehyde contents with high chlorophyll a, b and carotenoids contents and activity of superoxide dismutase, catalase and peroxidase enzymes under high Zn conditions. These findings confirm suggest that excess Zn adversely affects root growth and mitotic efficiency, enhances chromosomal aberrations and increases growth and nutrient accumulation abnormalities, as well as oxidative stress.

Sucrose phosphate synthase (SPS; EC 2.4.1.14) and sucrose synthase (SS; EC 2.4.1.13) are key enzymes in the synthesis and breakdown of sucrose in sugarcane. The activities of internodal SPS and SS, as well as transcript expression were determined using semi-quantitative RT-PCR at different developmental stages of high and low sucrose accumulating sugarcane cultivars. SPS activity and transcript expression was higher in mature internodes compared with immature internodes in all the studied cultivars. However, high sugar cultivars showed increased transcript expression and enzyme activity of SPS compared to low sugar cultivars at all developmental stages. SS activity was higher in immature internodes than in mature internodes in all cultivars; SS transcript expression showed a similar pattern. Our studies demonstrate that SPS activity was positively correlated with sucrose and negatively correlated with hexose sugars. However, SS activity was negatively correlated with sucrose and positively correlated with hexose sugars. The present study opens the possibility for improvement of sugarcane cultivars by increasing expression of the respective enzymes using transgene technology.

Sugarcane is one of the best converter of solar energy into biomass and sugar. The biomass which contains fiber, lignin, pentosans and pith can be converted into value added products by application of suitable chemical, biochemical and microbial technologies. The processing of sugarcane generates bagasse, molasses and press mud which has great economic value. Besides these main byproducts, there are other residues which are produced from sugarcane and have less commercial value such as trash, green tops, wax, fly ash and spent wash. Indian sugar industry has been processing these by-products to generate bioethanol, bio-electricity and many value added products in Sugar-Agro-industrial Complexes.