Malto-oligosaccharides

Malto-oligosaccharides (MOS) are low sweeteners with properties like antistaling effect on bread, high water holding capacity, and preventing sucrose crystallization.

Although α-amylases produce maltose or glucose from starch, some of the micro- bial α-amylases lead to the production of malto-oligosaccharides which may have their applications in MOS containing syrups (Park 1992).

Method of Production

10.8.1.1 Enzyme Involved

The following are enzymes which play a role in the production of malto-oligosaccharides:

1. α-Amylase (EC 3.2.1.1; 1 → 4-α-D-glucanohydrolase or endoamylase) results in the hydrolysis of starch by cleaving α-D-(1 → 4) glycosidic linkages, thereby producing specific or mixed malto-oligosaccharides.

2. α-Amylase (EC 3.2.1.2) results in the hydrolysis of starch by formation of maltose, followed by transglucosylation of maltose using α-glucosidase (EC 3.2.1.20).

3. Cyclodextrin glucanotransferase (CGTase) results in the formation of β-malto-oligosaccharides through glycosylation of bioactive tocopherols and isoflavones.

10.8.1.2 Process

Microbial amylases have been produced by Bacillus sp. (Nagarajan et al. 2006), Brachybacterium sp. (Doukyu et al. 2007), Marinobacter sp. (Kumar and Khare 2012), etc. for the synthesis of MOS. The transformation of maltose into isomalto-

oligosaccharide using α-glucosidase from Xanthophyllomyces dendrorhous has been reported (Fernández-Arrojo et al. 2007). The production of α-amylases has also been carried out using agro-industrial waste/by-products, such as sugarcane molasses, cheese whey, rice husk, and wheat bran (Babu and Satyanarayana 1995; Baysal et al. 2003; Sodhi et al. 2005). B. subtilis has been reported to produce α-amylases on sugarcane bagasse hydrolysate (Nagarajan et al. 2006; Rajagopalan and Krishnan 2008).

Immobilized Penicillium lilacinum dextranase on Eupergit C resulted in isomaltooligosaccharides production with 90 % relative activity up to 20 batch reactions (Aslana and Tanriseven 2007). A sandwich-structured enzyme membrane reactor has been used to convert maltose into isomalto-oligosaccharide with 100 % conversion and 58 % yield (Zhang et al. 2010). Transglucosidase producing A. niger has been reported to form various MOS (DP 2–8) from mixture of maltoheptaose and [U–13C] maltose (Ota et al. 2009). The synthesis of β-malto-oligosaccharides has also been carried out from glycitein and daidzein using Lactobacillus delbrueckii and cyclodextrin glucanotransferase (CGTase) by sequential glycosylation (Shimoda and Hamada 2010). Similarly, β-malto-oligosaccharides as tocopherol derivatives were synthesized by glycosylation of α and δ-tocopherols using Klebsiella pneumoniae and CGTase (Shimoda et al. 2009).

 
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