Starch Analysis Using Thermostable alpha‐Amylases

Abstract

A new method is described for determining the starch content of cereal products. It involves the solubilization of starch with a thermostable a-amylase followed by the complete hydrolysis with an amyloglucosidase. The glucose is then determined by the hexokinase/glucose-6 phosphate dehydrogenase procedure. By using an aamylase at high temperature, an autoclave is not required to gelatinize and solubilize the starch prior to amyloglucosidase treatment. a-Amylase is added to the sample before heating and degradation begins as soon as the gelatinization temperature is reached, before retrogradation can occur. The procedure was found to be superior to either treatment with acid or alkali, methods which also do not require an autoclave. Starkebestimrnung unter Verwendung thermostabiler aAmylasen. Eine neue Methode zur Bestimmung des Starkegehaltes von Getreideprodukten wird beschrieben. Sie beinhaltet die Losung der Starke mit einer thermostabilen a-Amylase, gefolgt von der vollstandigen Hydrolyse mit einer Amyloglucosidase. Die Glucose wird dann durch das Hexokinase/Glucose-6-phosphat-dehydrogenase-Verfahren bestimmt. Durch die Verwendung einer a-Amylase bei hoher Temperatur wird ein Autoklav zur Verkleisterung und Losung der Starke vor der Amyloglucosidasebehandlung nicht benotigt. Die a-Amylase wird der Probe vor der Erhitzung zugesetzt, und der Abbau beginnt, sobald die Verkleisterungstemperatur erreicht ist, bevor Retrogradation eintreten kann. Das Verfahren war denen mit Saure-oder Alkalibehandlung iiberlegen, Verfahren, die ebenfalls keinen Autoklaven erfordern.

Nutritional properties of green gram germinated in mineral fortified soak water: I. Effect of dehulling on total and bioaccessible nutrients and bioactive components

“…Fat was estimated by repeated distillation in a Soxhlet apparatus (Raghuramulu et al 2003). For measurement of total starch, starch was degraded to glucose with enzymic hydrolysis followed by determination of glucose (Batey and Ryde 1982;Raghuramulu et al 2003). Total ash was determined by incineration of sample in a muffle furnace and weighing.…”

Partial replacement of starch with acid detergent fibre and/or neutral detergent soluble fibre at two protein levels: Effects on ileal apparent digestibility and caecal environment of growing rabbits

“…Starch content was determined according to Batey (1982), by a two-step enzymatic procedure with solubilisation and hydrolysis to maltodextrins with thermo-stable α-amylase followed by complete hydrolysis with amyloglucosidase (both enzymes from Sigma-Aldrich, Steinheim, Germany), and the resulting glucose being measured by the hexokinase/glucose-6 phosphate dehydrogenase/NADP system (R-Biopharm, Darmstadt, Germany). Neutral detergent fibre (NDF), ADF and acid detergent lignin (ADL) fractions were analysed sequentially (Van Soest et al, 1991) with a thermo-stable α-amylase pretreatment and expressed exclusive of residual ash, using a nylon filter bag system (Ankom, Macedon, NY, USA).…”

Effect of oxidation state of dietary sunflower oil and dietary zinc and α -tocopheryl acetate supplementation on performance of fattening rabbits

“…Starch content was determined according to Batey (1982), by a 2-step enzymatic procedure with solubilisation and hydrolysis to maltodextrins with thermo-stable α-amylase followed by complete hydrolysis with amyloglucosidase (both enzymes from Sigma-Aldrich, Steinheim, Germany), and the resulting glucose were measured by the hexokinase/glucose-6 phosphate dehydrogenase/NADP system (R-Biopharm, Darmstadt, Germany). Crude fibre (CF), neutral detergent fibre (NDF), acid detergent fibre (ADF) and acid detergent lignin (ADL) of diets were determined using filters bags and a Fiber Analyser A220 (ANKOM, USA) and following AOAC official methods, 978.10 for CF and 973.18 for ADF and ADL (AOAC, 2000) and Mertens (2002) for NDF.…”