Combination of amylase and transferase catalysis to improve IMO compositions and productivity

Abstract

Isomaltooligosaccharides (IMOs) is a mixture of branched-maltooligosaccharides (MOSs), classified as a functional food ingredient with prebiotic potential. The objective of this study was to investigate alternative enzymatic methods to produce a sweetness/viscosity/degradability balance product containing soluble carbohydrate ranging from glucose, maltose, isomaltose and linear and branched MOS (IMOs), of different digestibility. The modified samples were produced using two main routes: 1. simultaneous catalysis by α-amylase and branching enzyme (BE) followed by α-transglucosidase (ABT) treatment, 2. simultaneous catalysis by α-amylase and BE followed by simultaneous β-amylase and α-transglucosidase (ABbT). For both routes, 30% or 50% (w v−1) cassava starch were used and a commercial IMO (comIMO) preparation was used as a positive control. The 30ABbT and 50ABbT showed the highest α-1,6 glucosidic linkages, panose and branched MOS (Degree of Polymerisation (DP) 4–7) compared to all other samples. All ABT and ABbT products showed decreased molecular weight and increased resistance to degradation by amylolytic enzymes as compared to cassava starch. The 50ABbT sample demonstrated the lowest digestion rate constant. Due to their high solubility and structural composition, containing-balanced-glucose, maltose, isomaltose and linear and branched MOS (IMOs), of different digestibility, these compositions can be suitable especially in soft drink- and sport drink formulations.