Effect of Reducing Sugars on Non-enzymic Browning During Thermo-Evaporation of Sugarcane Juice for Making Jaggery

Abstract

Jaggery samples were prepared from sugarcane juice having different concentrations of reducing sugars (by adding glucose/fructose) for studying the contribution of invert sugars towards colour development of jaggery by non-enzymic browning reactions during jaggery making process. Addition of 0.5 and 1.0 g glucose/100 ml cane juice did not alter the colour of juice after boiling for 30 min at 98 °C, while addition of same quantities of fructose/100 ml in the cane juice enhanced the colour of boiling juice over control. Further, evaporation of cane juice till 118 °C for preparation of jaggery indicated that the colour of jaggery samples prepared from juice having additional 0.5 and 1.0 g fructose/100 ml juice increased indicating more contribution of fructose towards darkening of colour development of jaggery during thermo-evaporation process. As the pH of juice remained below 6 through out the jaggery making process, fructose of cane juice seemed to be contributing more towards colour of jaggery in comparison to glucose in the non-enzymic browning. This was indicated by significantly more colour development by caramelization of fructose at 118 °C in comparison to glucose and sucrose since carbonyl–amine browning does not take on much significance until the pH is greater than 6.