Studies on Physicochemical, Pasting Characteristics and Amylolytic Susceptibility of Starch from Sorghum (Sorghum bicolor L. Moench) Grains

Abstract

Preparation, physicochemical properties, pasting behavior and amylolytic susceptibility of sorghum starch have been investigated. The yield of starch was about 60.25%, on whole grain basis. The starch exhibited double stage swelling and low solubility pattern in an aqueous system. Viscoamylographic studies on pasting behaviour of the starch revealed a peak viscosity of 800 B. U. at 8% (w/v) concentration; however, it decreased considerably during cooking (viz.holding period of 30 min at 93°C). The amylose content of the starch was 23.45%. The gelatinization temperature range was found to be 68.5-72.5-78.5"C. The results indicated that the native starch hydrolyzed to a limited extent by human salivary a-amylase and glucoamylase as compared to gelatinized starch. In addition, the mode of attack by amylolytic enzymes on the native starch granules viewed by SEM has been studied in detail. Untersuchungen uber physikalisch-chernische Eigenschaften, Verkleisterungscharakteristika und arnylolytische Angreifbarkeit von Starke aus Sorghurnkornern (Sorghum bicolor L. Moench). Die Gewinnung, das physikalisch-chemische und das Verkleisterungsverhalten sowie die amylolytische Angreifbarkeit von Sorghumstarke wurden untersucht. Die Starkeausbeute betrug 60,25%, bezogen auf das Ganzkorn. Die Starke zeigte zweistufige Quellung und geringe Loslichkeit in Wasser. Viskoamylographische Untersuchungen des Verkleisterungsverhaltens der Starke zeigte eine Spitzenviskositat von 800 BE bei 8Y0iger (w/v) Konzentration, die sich jedoch wahrend der Kochperiode (30 min bei 93°C) betrachtlich verringerte. Der Amylosegehalt der Starke war 23,45%. Der Verkleisterungstemperaturbereich lag bei 68,5-72,5-78,5"C. Die Ergebnisse deuten darauf hin, daR die native Starke nur in begrenztem MaR durch menschliche Speichel-a-Amylase hydrolysiert wird, verglichen mit verkleisterter Starke. Zusatzlich wurde die Art und Weise des Angriffs durch amylolytische Enzyme auf die nativen Starkekorner durch SEM im einzelnen untersucht.

Effect of Fiber Degrading Enzymes on Wet Milling and Starch Properties of Different Types of Sorghums and Maize

“…An increase in SO 2 and/or lactic acid concentration or the utilization of proteolytic enzymes could improve the sorghum starch refining process [6][7][23][24]. Starch yields obtained from sorghum in this study are similar or higher than the obtained by Kulkarni et al [25], Watson [5], Watson and Hirata [12] and Wankhede et al [26]. The WWx had a significantly higher starch yields and recoveries at both steeping solutions and times (p < 0.05) than the RS and WHWx.…”

Physicochemical properties, modifications and applications of starches from different botanical sources

“…Wild type A-type: Disc-shape (Ellis et al, 1998) B-type: lenticular (Ellis et al, 1998) A-type:10-25 (Ellis et al, 1998) B-type: 5 (Ellis et al, 1998) 0.7-1.2 (Morrison et al, 1984) 0.2-0.4 (Ellis et al, 1998) 19-22.1 (Ellis et al, 1998) 25.3-30.1 (Morrison et al, 1984) Waxy A-type:10-25 (Ellis et al, 1998) B-type: 5 (Ellis et al, 1998) 0.3-0.5 (Morrison et al, 1984) 0.06-0.15 (Ellis et al, 1998) 1.8-3.6 (Ellis et al, 1998) 2.1-8.3 (Morrison et al, 1984) High amylose A-type: 15-32 (Ellis et al, 1998) B-type :2-3 (Ellis et al, 1998) 1.0-1.7 (Morrison et al, 1984) 18.2-24.1 (Ellis et al, 1998) 38.4-44.1 (Morrison et al, 1984) Sorghum Wild type Polygonal, dented and round (Wankhede et al, 1989) 8-14,5 polygonal, 8-10 round (Wankhede et al, 1989) 0.8 (Emmambux & Taylor, 2013) 2.3 (Emmambux & Taylor, 2013) 23.7-27.6 (Boudries et al, 2009) 26-30/A (Boudries et al, 2009) Waxy Larger than normal sorghum (Lawal et al, 2011) 5-25 (Sang et al, 2008) < 0.3 (Sang et al, 2008) 3.5 (Sang et al, 2008) 0 (Sang et al, 2008) Heterowaxy 14 (Sang et al, 2008) …”

Sorghum

“…Typical gelling temperatures for sorghum starch cover the range 68 -78°C for onset to completion of gelation; this is similar but slightly higher than the range for normal maize starch [39]. Typical pasting temperatures are in the order of 75°C with peak viscosities around 330 BU [39,40]. A comparison of the swelling and solubility properties of sorghum and wheat starch has been carried out by Carcea et al [37] the results are summarized in Figs.…”

“…A study of the hydrolysis of starch from maize and sorghum using a-amylase [40] has shown that the lower digestibility (l5-25% compared to maize) probably results from affects from the protein, since pre-treatment with a protease before cooking res tores some of the digestibility. The cause of this effect is not obvious since, unlike wheat, the protein matrix around the starch is not continuous but contained in bodies.…”

“…There is evidence to suggest that in sorghum grain gelatinization may be restricted [39] and the digestibility of sorghum starch may be lower than that of other starches [40], even in low tannin sorghums. A study of the hydrolysis of starch from maize and sorghum using a-amylase [40] has shown that the lower digestibility (l5-25% compared to maize) probably results from affects from the protein, since pre-treatment with a protease before cooking res tores some of the digestibility.…”