Production of Maltooligosaccharides from Black Potato (Coleus tuberosus) Starch by α-amylase from a Marine Bacterium (Brevibacterium sp.)

*Corresponding author; Phone/Fax: 021-8765066/0218765062, Email: rahmani_btk@yahoo.com Starch is the most abundant storage polysaccharide in cereal and legume grains, many roots, and in tubers (vander Maarel et al. 2002; Belitz et al. 2004); the polysaccharide consists of the two glucose polymers amylose and amylopectin. The former is a linear α-(1-4) linked glucose chain with a plant-specific degree of polymerization of 200-6000; the latter consists of short linear α-(1-4) linked chains with α-(1-6) linked side chains (vander Maarel et al. 2002). Starch is hydrolyzed into smaller oligossaccharides by α-amylase, wich is one of the most important commercial enzyme processes (Souza and Pérolade 2010). Oligosaccharides (OS) have been commercialised since the 1980s as low-calorie bulking agents. The functional food concept was first introduced in Japan. In 1991, several oligosaccharides were classified as “foods for specified health use” (FOSHU) in Japan. Recent research findings across the globe, have led to the inclusion of non-digestible oligosaccharides (NDOs) under functional food. Currently, there exist a 27 billion USD market for functional foods and experts forecast its 8.5-20% growth. The global market for functional foods was valued at 73.5 billion USD in 2005, whereas by 2013, it is expected to reach a value of 90.5 billion USD (Patel and Goyal 2011). In general, various kinds of oligosaccharides can be produced from starch as the raw material, such as maltooligosaccharides (maltose, maltotriose, maltotetraose, maltopentaose, and maltoheptaose), isomaltooligosaccharides (isomaltose, panose, and isomaltotriose), cyclodextrins (CDs) (α-CD, β-CD, γ-CD, HPβ-CD, and branched CDs), maltitol, gentiooligosaccharides, trehalose, and nigerose. Maltooligosaccharides are by definition glucose oligomeres consisting of 2 to 10 glucopyranosyl residues linked via α-1-4 bonds High quality maltooligosaccharides were produced from indigenous Indonesian black potato starch by making use of an amylase from Brevibacterium sp. Optimal production was achieved at 2.5% (w/v) substrate concentration, an enzyme-substrate ratio of 1:5 (w/v) and hydrolysis time of 4 h. Under such conditions the yield of reducing sugars was 14 240 ppm with a polymerization degree of 16. Thin layer chromatography (TLC) revealed the formation of glucose, maltose, and maltotriose with Rf values of 0.60, 0.52, and 0.37, respectively. HPLC analysis of freeze-dried samples disclosed Rf values of 0.60, 0.50, 0.37, and 0.12. Maltooligosaccharide profile analysis both using TLC and HPLC showed that the enzymatically hydrolyzed samples contained glucose, maltose, and maltotriose. Thus, black potato starch can be randomly converted into simple sugars and maltooligosaccharides applying by amylolytic enzymes from the marine microbe Brevibacterium sp.