Effect of harvest method and storage time on sugarcane deterioration II: oligosaccharide formation.
Eggleston, G., Legendre, B. and Richard, C.
International Sugar Journal. Volume 103, Number 1235, 2001. Pages 495-504.
2001
บทคัดย่อ
The recent increase of billeted cane being combine harvested in Louisiana (USA) has often meant an increase in deteriorated cane being processed. There is a real need to establish new and more sensitive criteria to measure deterioration in Louisiana harvested cane to better predict cane quality and the effect of harvest methods and storage conditions. In this study, eight cane supply treatments were evaluated, with samples taken on each day for four consecutive days (0, 24, 48 and 72 h) before laboratory milling and analyses. Three treatments included handcut whole-stalk cane that was either hand stripped of leaves (control), left unstripped (green), or burnt. The other treatments included soldier harvested cane that was either burnt or green, or burnt and stored to simulate cane from a heap or transloader stack each day. Two other treatments, burnt and green billeted cane from the combine harvester, were also used to simulate cane from a billet wagon each day. Cane quality changes on deterioration were described in Part I of this paper, and included changes in TRS, colour, invert, dextran, pH, and titratable acidity. Part II of this paper describes oligosaccharide formation in cane, with emphasis on both kestoses (up to GF5) and those formed as products from dextran formation by dextransucrase from Leuconostoc mesenteroides. In the fresh (0h) samples, for all eight harvest treatments, there were no marked differences in oligosaccharide profiles, indicating that when the field cane is cut, freshness is more important than harvest method. Oligosaccharide formation was greater and more rapid in billeted than whole-stalk cane, concomitant with a decrease in pH and an increase in dextran. Deterioration occurred earlier in billeted than whole-stalk cane, and was more rapid and extensive in burnt than green billets. A full statistical analysis is described. Optimum postharvest handling conditions to minimize grower and factory losses are discussed. [This paper is also published (without the Spanish summary) in Sugar Cane International (2001) 103 (1235), pp. 15-20].