Physicochemical Properties of Xylitol Crystals from Oil Palm Empty Fruit Bunches Hydrolysate

Abstract

Xylitol, a low-calorie sugar made up of five carbon atoms, had the valuable characteristics suitably applied for pharmaceutical and food industries. This sugar can be produced from oil palm empty fruit bunches (OPEFB) through hydrolysis and followed by fermentation. The xylitol in the fermentation broth requires the downstream process to obtain the final product with high purity and yield. Among a series of xylitol downstream process, crystallization becomes a critical step since this process determines the properties of final products. The objective of this study was to evaluate the effect of evaporation temperature (55°C and 70°C) and seeding addition (0%, 0.1%, 0.5%, 1 %) in the crystallization step on the physicochemical properties of xylitol crystals obtained from the OPEFB hydrolysate. The main evaluation criteria were crystal contents, purity, melting point, water content, hygroscopicity, solubility, caloric content, and crystal xylitol yield. The result showed that the crystal form obtained was relatively sticky and had lower purity than commercial ones because the concentration of xylitol solution increased after evaporation. The differences of physicochemical properties of the crystals such as the purity, porosity, yield and crystal form were influenced by evaporation temperature. The crystals formed by 70°C evaporation temperature produced the crystals with higher caloric value and purity, but it had lower hygroscopicity and moisture content than crystals formed by 55°C. However, the percentage of seeding gave an insignificant impact on xylitol crystal properties.

Xylitol Production from Aspergillus niger using Empty Fruit Bunches (EFBs) as a Substrate by Submerged Fermentation

“…The EFBs that used in this research was obtained from PTPN IV, Bah Jambi, North of Sumatera. The preparation procedure followed the procedures in the research of Mardawati [14]. EFBs were soaked for 24 hours, the fiber was collected, and then cleaned using distilled water to remove impurities.…”

“…EFBs consisting of 45.95% cellulose, hemicellulose 22.84%, and lignin 16.49% [12]. Hemicellulose is the component to be used as the main raw material in the manufacture of xylitol because the monomeric sugar utilized for xylitol production is xylose obtained from hemicellulose degradation [14]. Production by submerged fermentation method is most often to production of xylitol [15] [16].…”

Fermentation Based Sugar-Alcohol Downstream Processing: A Review

“…Crystallization techniques could be performed using solvent evaporation to increase solute concentration, cooling to reduce solubility, precipitation, and salting-out. Another parameter that affects the crystallization process is seeding that would accelerate the crystallization process [18]. Therefore, this method depends on substance solubility and the related temperature [4].…”

“…At another work, the fermentation broth was separation by adsorption with 30 g/L activated carbon at room temperature for 1 h. The yield of the xylitol crystal observed was 49,32%, and it has a low whiteness index value [5]. Due to the result that the solution had been purified using activated charcoal, by-products still existed in the final product [18,24].…”

“…[10,11,13]. The moisture content of xylitol crystals produced by 70°C evaporation temperature was lower than that formed by 55°C evaporation temperature because crystallization at lower temperatures produces higher porosity [18].…”