Effects of operating parameters on acid hydrolysis of ground wheat starch: Maximization of the sugar yield by statistical experiment design

Abstract

AbstractFuels and chemicals production from carbohydrate rich waste materials has received considerable attentions in recent years. Pretreatment and hydrolysis are required stages during processing the waste materials for this purpose. Therefore, the objective of this study was to determine the optimum operating conditions in acid hydrolysis of ground wheat (GW) starch for maximum yield of total sugar (TS) formation. Hydrolysis reaction was realized by dilute sulfuric acid and heat treatment in an autoclave. Factorial experiment design was used to determine the significant variables affecting the yield of hydrolysis. The independent variables were particle size (Dp = <74 and 220 µm), acid concentration (A = 0.98–196 g/dm3), GW concentration (GW = 10–20 g/dm3), hydrolysis temperature (T = 90–130°C), and time (t = 5–60 min). The dependent variables were final TS concentration and hydrolysis yield (YH). The significant factors in the hydrolysis of GW were determined as GW concentration, acid (A) concentrations, and hydrolysis temperature (T). Box–Wilson statistical experimental design was used for optimization of hydrolysis conditions by considering the signficant factors. The optimal conditions, maximizing the hydrolysis yield (YH = 0.94) were A = 49 g/dm3 (0.5 M), T = 90°C, GW = 35 g/dm3 and t = 15 min. The most suitable A/GW ratio for the maximum hydrolysis yield of 94% was 1.3.