ABSTRACT

Analysing the processing quality of sugarcane Charley Richard, Sugar Processing Research Institute and the New York Sugar Trade Laboratory, USA

1 Introduction

2 Composition of the whole sugarcane plant

3 Composition of sugarcane juice: sucrose, glucose and fructose

4 Other constituents in cane juice

5 Composition of sugarcane fibre and bagasse

6 Variation in juice composition

7 Production, harvesting and extraction

8 Sugarcane quality and grower payments

9 References

Sugarcane, a tropical grass belonging to the genus Saccharum, is different in its composition from many other grasses. At harvest time, the entire plant consists of roots, below-ground portions of the stalk, above-ground mature stalk (millable cane), leaves (green and dead), leaf sheaths and possibly immature upper portions of the stalk which includes the growing point. Except for roots and below-ground portions of the stalk every other part of sugarcane is normally harvested in commercial production. However, efficient industries attempt to separate as much of the extraneous plant matter from the millable stalk as possible and deliver only the mature portion of the harvested stalk to the sugar factory. A closer examination of the compositional analysis of the sugarcane plant reveals that there is tremendous variation amongst the species of sugarcane as well as clones within the species and commercial varieties. There is also seasonal variation since the stalk matures from the ground upwards and early in the season there will be a lower percentage of mature stalk as compared to later in the season. Variation can also be found among years, among production and fertilization practices, pest occurrence and other factors. However, it has been generalized that approximately three-fourths of the above-ground portion of the sugarcane plant can be considered as mature millable stalk, which is the most valuable portion from a sugar production perspective. As the value of fibre and other non-sucrose constituents changes, one might consider the remaining

one-fourth as important saleable items rather than extraneous matter as currently defined. Understanding and analysing these components is important in realizing the maximum value for sugarcane deliveries in a sustainable industry.