Cooperative Test on Amylography of Milled‐Rice Flour for Pasting Viscosity and Starch Gelatinization Temperature

Abstract

An ICC cooperative test on Amylograph viscosity of milled-rice flour involving 11 laboratories and 4 contrasting rice samples was undertaken to determine the reproducibility of the method. The highest contribution to total variance was from sample followed by laboratory and then sample x laboratory. Only 2 of 9 laboratories showed similar peak viscosities on the samples, only 3 of 8 laboratories had similar cooked paste final viscosities, but none of 7 laboratories had similar cooled paste final viscosities using preground flour and a c o m m o n method. Use of individual mills to prepare flour for the c o m m o n method and use of 1 a b o r a t o r y method with preground flours increased variance due to laboratory and reduced the contribution of sample. Final gelatinization temperature of starch may be readily estimated from the apparent temperature of 20 BU intercept of the Amylograph curve of 20% preground paste from the results of 5 laboratories with 700g . cm cartridge. Gemeinschaftsuntersuchung der amylographischen Messung vonReismehl hinsichtlich der Pastenviskositat und der Starke-Verkleisterungstemperatur. Ein 1 I Laboratorien umfassendes gemeinschaftliches Projekt der ICC (International Association of Cereal Chemists) befafite sich mit der Priifung des amylographischen Verhaltens von 10% vorvermahlenem Mehl von 4 bezuglich der Verkleisterungseigenschaften stark differierenden Reissorten unter Verwendung einer dem Zweck angepal3ten allgemeinen Methode von Halick und Kelly [2]. Der Test zeigte signifikante Abweichung aufgrund von Probe, Laboratorien sowie Wechselwirkung zwischen Probe und Laboratorium, Uberlaufen der Probe sowie Unterschiede in der Wirksamkeit von Erhitzung und Abkiihlung, in der Verkleisterungszeit und in der scheinbaren Temperatur bei der Spitzenviskositat zwischen den einzelnen Apparaten spiegelte Unterschiede in der Temperaturkontrolle wieder. Die Spitzenviskositat wurde im Gegensatz zu der Viskositat der gekochten und abgekuhlten Paste durch andere Faktoren als die Probe selbst beeinflufit. Die Laboratoriumsmuhle und die Laboratoriumsmethode trugen ebenfalls zu den Abweichungen der Amylograph-Viskositiiten bei. Beziiglich der Verkleisterungstemperatur 20%iger Pasten, d . h. der Temperatur, die dem Schnittpunkt der Viskositatskurve mit der 20 BU-Linie (BU = Brabender Units) bei Verwendung der 700 g.cm-MeBdose entspricht, korrespondierte mit der durch Photometrie und Doppelbrechungs-Endpunkt-Temperatur (BEPT) gemessenen Verkleisterungstemperatur. 42 starch/st%rke 37 (1985) Nr. 2, s. 40-50

Degree of Milling Effects on Rice Pasting Properties

“…Total lipid content of each ground sample was determined with a Soxtec fat extractor using petroleum ether as solvent (Approved Method 30-20, AACC 2000). The MC of the ground rice was measured by drying 2-5 g samples for 1 hr in an oven at 130°C (Juliano et al 1985). The MC values were used to calculate the amount of rice flour needed to prepare the rice flour slurry for pasting properties measurements.…”

Effects of Long‐Grain Rough Rice Storage History on End‐Use Quality

“…For amylography, head rice (60g) was ground in a UDY Cyclotec mill (Model 1093, Tecator, Inc., Hoganas, Sweden) with a 0.5 mm screen. The flour was mixed with water to produce a slurry with 8% dry matter, after determining the mc of the flour (Juliano et al, 1985). Subsequently, the slurry was subjected to a defined temperature treatment in a Brabender viscograph-E, according to a modified version of Method 61-01 (AACC, 1996) for milled rice.…”

Effects of Rough Rice Storage Conditions on the Amylograph and Cooking Properties of Medium‐Grain Rice cv. Bengal

“…The MC of the ground rice was measured using an air-oven method (Juliano et al 1985). The head rice was ground in a cyclone mill (Udy Corp., Fort Collins, CO) fitted with a 0.5-mm screen.…”

“…The head rice was ground in a cyclone mill (Udy Corp., Fort Collins, CO) fitted with a 0.5-mm screen. The MC of the ground rice was measured using an air-oven method (Juliano et al 1985). Slurry (500 g) containing 8% dry matter in water was used for the amylography.…”