A Rapid Method for the Determination of Amylose Content by Using Differential‐Scanning Calorimetry

Abstract

A calorimetric procedure to measure arnylose content of various starchy raw materials has been developed. It is based on the measurement by Differential Scanning Calorimetry (DSC) of the enthalpy change of the formation of complexes between amylose and add phospholipid (L-a-lysophosphatidylcholine from egg yolk) observed during cooling.Contrasting to the colorimetric determination of amylose, the DSC procedure is not influenced by the presence of amylopectin or indigenous lipids. For rice and maize flours, the amylose content determinations are very similar for both colorimetric and DSC methodologies whether the starchy material was raw or pre-cooked. But the DSC methodology is more repeatable and time saving; in particular, the defatting and starch determination steps can be omitted. -~~ ~ Eine schnelle Methode zur Bestimmung des Amylosegehaltes unter Anwendung der Differential-Raster-Calorimetrie. Eln calorimetrisches Verfahren zur Bestimmung des Amylosegehaltes verschiedener starkehaltiger Rohrnaterialien wurde entwickelt. Es basiert auf der Messung durch Differential-Raster-Calorimetrie (DSC) der Enthalpieanderung durch die Bildung von Komplexen zwischen Amylose und den Zusatz von Phospholipid (L-a-lysophosphatidylcholin aus Eigelb), beobachtet wahrend der Abkiihlung. Im Gegensatz zur kolorimetrischen Amylosebestimmung wird das DSC-Verfahren nicht durch die Gegenwart von Amylopektin oder innewohnende Lipide beeinflu&. Bei Reis-und Maismehlen sind die Bestimmungen des Arnylosegehaltes einander sehr ahnlich sowohl fur die kolorirnetrischen als auch fur die DSC-Methodologien, gleichgiiltig ob das starkehaltige Material roh oder vorgekocht war. Jedoch ist die DSC-Methodologie reproduzierbarer und zeitsparend; insbesondere konnen die Entfettungs-und Starkebestimmungs-Stufen wegfallen.

Discovery of an Amylose-free Starch Mutant in Cassava (Manihot esculenta Crantz)

“…The differential curve of the AM206-5 starch (obtained in 2006 from the original plant) in the cooling phase was very striking. The mixture of amylose and amylopectin in the gels from MCOL2208 and MPER247 absorbed energy for a molecular re-organization which was proportional to the area depicted in Figure 5 and has been demonstrated to be related to amylose concentration (29). The gel from AM206-5, on the other hand, did not show any energy absorption during the cooling phase further indicating absence of amylose in the starch.…”

“…The methodology reported by Mestres et al (29) was used. DSC analyses were performed on a Perkin-Elmer DSC 7 device (PerkinElmer, Norwalk, VA) using sealed stainless-steel pans.…”

Effect of physiological harvest stages on the composition of bioactive compounds in Cavendish bananas

“…Percentage fruit starch content was determined by differential scanning calorimetry (DSC) (Sievert and Holm, 1993;Mestres et al, 1996). For this study, 9 mg of freeze-dried pulp powder was extracted with 40 µl of water purified through a Millipore purification system.…”

Wheat Tortilla Quality: Impact of Amylose Content Adjustments Using Waxy Wheat Flour

“…In the first procedure, flour was dispersed in dimethyl sulfoxide 428 CEREAL CHEMISTRY (DMSO), and the modified colorimetric iodine (12) binding method of Knutson and Grove (1994) was followed. The second procedure used was a differential scanning calorimetry (DSC) method (Mestres et al 1996). Purified amylose from wheat starch was used to prepare a standard curve for the iodine (12) binding method, and blends of purified wheat starch amylose and amylopectin were used to generate the calibration curve for the DSC method.…”