Quick Method for Determination of Fructose-Glucose Ratio in Agave Syrup

Abstract

Fructose is 30% sweeter than sucrose, the sweetest natural sugar in the world and the main compound of agave syrup. Although fructose can be got from different syrups through a chromatographic system, the methods to evaluate their puriication are expensive and too long time. In this work, using a polarimetric method was determinate the fructose-glucose ratio from agave syrup before and after their process by a chromatography method. The polarimetric method was validated using a standard HPLC-based method. With the results of this work was development a rapid and economic technique to determinate the fructose-glucose ration in agave syrup. DOWEX MONOSPHERE 99 Ca 2+ /320 resin. he water low rate used was of 2.8 Lt/h. Polarimetric lectures Polarimetric standard curves were done using fructose-glucose solutions of know concentration. he calibration curves were done with 75% to 100% of fructose, at 10, 25, 30 and 40°Brix. he polarimetric lectures of the agave syrups samples and the fractions recollected ater submitted one agave syrup to a chromatography process were done with the ADS420 Automatic Digital Saccharimeter. he Brix of the agave syrup chromatography processed were adjusted before their lectures. High performance liquid chromatography (HPLC) lectures Fructose and glucose standard solutions were prepared as described Bogdanov et al. [8]. hese standard solutions were used as external reference for the HPLC lectures. he sugar solutions were prepared at 0, 25, 50, and 100 °Brix. he sugars determination through HPLC is described in detail by Bogdanov et al. [8]. he sugars concentrations were analyzed with a Diferential Refractometer Waters 410. Separation was achieved on a Phenomenex RNM-Carbohydrate Na + column (300 mm × 7.8 mm). Column temperature was maintained at 80°C with a heater (Eppendorf CH-30). he mobile phase consisted of deionized water that was run at 0.20 mL/min. Statistics Each experiment and analyses were replicated thrice. To compare reproducibility and accuracy of the results got from polarity and HPLC, the Anova variancy (ANOVA) statistical tools was used. Results Polarimetric lectures of standard fructose-glucose solutions Table 1 shows the results of polarimetric lectures (°Z) of standard