Properties of Cassava Starch Modified by Amylomaltase from Corynebacterium glutamicum.
Amylomaltase (α-1,4-glucanotransferase, AM; EC 2.4.1.25) from Corynebacterium glutamicum expressed in Escherichia coli was used to prepare the enzyme-modified cassava starch for food application. About 5% to 15% (w/v) of cassava starch slurries were incubated with 1, 3, or 5 units of amylomaltase/g starch. Apparent amylose, amylopectin chain length distribution, thermal properties, freeze-thaw stability, thermo-reversibility, and gel strength of the obtained modified starches were measured. The apparent amylose content and retrogradation enthalpy were lower, whereas the retrogradation temperatures, freeze-thaw stability, and thermo-reversibility were higher than those of the native cassava starch. However, when amylomaltase content was increased to 20 units of amylomaltase/g starch and for 24 h, the modified starch showed an improvement in the thermo-reversibility property. When used in panna cotta, the gel strength of the sample using the 20 units/24 h modified cassava starch was similar to that of using gelatin.
Dept. of Food Technology, Faculty of Science, Chulalongkorn Univ, Bangkok, 10330, Thailand.
Pitcha
P
Suriyakul Na Ayudhaya
Starch and Cyclodextrin Research Unit, Dept. of Biochemistry, Faculty of Science, Chulalongkorn Univ, Bangkok, 10330, Thailand.
Piamsook
P
Pongsawasdi
Dept. of Food Technology, Faculty of Science, Chulalongkorn Univ, Bangkok, 10330, Thailand.
Kalaya
K
Laohasongkram
Dept. of Food Technology, Faculty of Science, Chulalongkorn Univ, Bangkok, 10330, Thailand.
Saiwarun
S
Chaiwanichsiri
D000687:Amylopectin / Q000032:analysis / Q000378:metabolism; D000688:Amylose / Q000032:analysis / Q000378:metabolism; D048230:Corynebacterium glutamicum / Q000201:enzymology*; D004040:Dietary Carbohydrates / Q000032:analysis*; D004926:Escherichia coli / Q000378:metabolism; D005511:Food Handling / Q000379:methods; D006004:Glycogen Debranching Enzyme System / Q000378:metabolism*; D006801:Humans; D002365:Manihot / Q000737:chemistry*; D013213:Starch / Q000032:analysis* / Q000378:metabolism; D013696:Temperature
D004040:Dietary Carbohydrates; D006004:Glycogen Debranching Enzyme System; D013213:Starch; D000688:Amylose; D000687:Amylopectin; C020569:4 alpha-glucanotransferase
amylomaltase; cassava starch; freeze-thaw stability; retrogradation; thermal properties; thermo-reversibility