Impact of Sugarcane Juice Clarification on Physicochemical Properties, Some Nutraceuticals and Antioxidant Activities of Non-centrifugal Sugar

In Thailand, non-centrifugal sugar (NCS) product is not yet processed on an industrial scale and all of it is produced by famers on a small scale using a traditional evaporation process with open iron pans. Since the whole sugarcane stalk is directly pressed by a milling machine, impurities from the rind contaminate the raw juice. Therefore, subsequent clarification of the raw juice is a crucial step to produce the high-quality NCS product. The farmers normally use traditional filtration, and sometimes non-food-safe additives to remove suspended impurities from the raw juice. This study examined and analysed the effects of the food additives calcium oxide (CaO) and sodium hydrogen carbonate (NaHCO3) on the physicochemical properties of NCS, and the results will be used to guide and improve traditional-level production. Clarifying the juice at pH 8.5 with CaO gave the greatest mud weight (47.52g) and the lowest sediment value of NCS (0.68%), while clarifying the juice with the maximum studied level (0.1% w/v) of NaHCO3 gave the mud weight and sediment values of 30.28g and 0.71%, respectively. The higher the amount of clarifier, the cleaner the juice obtained. Clarification by NaHCO3 or CaO caused different effects on the moisture content, water activity and colour of the NCS, but had no impact on its solubility. Total phenolic content and total flavonoid content were positively correlated with antioxidant activity by the ABTS radical scavenging assay. Clarifying the juice with CaO or sodium NaHCO3 caused loss of policosanol and tricin contents.