M Saska, RM Ruiz and S Zossi
Estación Experimental Agroindustrial Obispo Colombres (EEAOC), Av. William Cross 3150, Las Talitas, Tucumán, Argentina, CP: T4101XAC; drmsaska@gmail.com
Increased levels of colorants (particularly the melanoidins) produced by decomposition of sugars in sugar boiling via the so called Maillard reaction, have a negative effect on sugar quality and recovery. Additionally, higher molasses color was reported to lead to lower yields in ethanol fermentation. With the goal of quantifying the possible impact on the industry, we surveyed final molasses color in samples produced in Tucumán in 2022 and 2023. With the color normalized to the same Brix and purity, there were significant differences amongst the factories. At 80 Bx and 60 % Bx fermentable sugars, color ranged from 60 to 250 color units (CU). In other tests, molasses samples were kept for 6 and 12 hours at temperatures ranging from 82 to 92 °C. A reasonably good relationship (R2 = 0.93) was found between the color increase and fermentable sugar loss. 18–52% of the initial glucose and 10–39% of the fructose were lost, while the total FS loss on the Brix basis was between 2 and 8%. This indicates that the Maillard reaction, in which glucose is known to react faster than fructose, was significant. For every 17 CU increase (color as measured with the simplified procedure described in the paper) or about 9000 ICUMSA color units, about 1% of the initial fermentable sugars were lost. Therefore, monitoring color changes in sugar boiling may provide an estimate of how much fermentable sugar is being lost in the process.