The basic principle for the synthesis of kestoses involves the action of invertase on sucrose. Invertase hydrolyses sucrose, producing glucose and fructose. Invertase also plays a very important role in kestose synthesis: It transfers the fructosyl residue (resulting from hydrolysis of sucrose) onto the fructose residue of sucrose (1- and 6- kestose) or the glucose residue of sucrose (neo-kestose). In this way, the respective kestoses (1, 6 and neo) are created. The method used for the synthesis of the kestoses was adapted from Gross (1962). 3.2.1. Reagents and instrumentation These kestoses were investigated together because they are synthesised together during the reaction. The following reagents and instruments were used for all optimisation methods …show more content…
All standards, samples and solvents were filtered using filtered using 0.45 µm Sartorius Stedim, cellulose nitrate filter paper prior to HPLC-PAD analysis. The HPLC-PAD system consisted of a PAD detector, Perkin Elmer pump and ALS, CarbopakPA1 (4 × 250 mm) and CarbopakPA1 Guard Column (21.7 °C). The PAD detection range was set at 300 K (E1: 0.05 V, E2: 0.76 V, E3: -0.20 V). The injection volume used for analysis was 50 µL and the analysis time for each sample and standard was set at 30 minutes. The solvent system used for analysis was 10 mM NaOAc/ 150 mM NaOH and the kestoses were eluted at a flow rate of 1 mL /min. 3.2.2. Investigation of reaction parameters There are certain reaction conditions that may favour the production of one kestose isomer over the other. Therefore, several parameters (pH, temperature and time) were chosen and investigated to develop the optimum reaction conditions for each of the kestoses. The experiments for each parameter was carried out in triplicate. Reaction