Production of short‐chain fructooligosaccharides (scFOS) using extracellular β‐D‐fructofuranosidase produced by Aspergillus thermomutatus

• Published in: Journal of food biochemistry 2019-08, Vol.43 (8), p.e12937-n/a
• Main Authors: Tódero, Larissa Midiane, Rechia, Carem Gledes Vargas, Guimarães, Luis Henrique Souza
• Format: Article
• Language: English
• Subjects: Aspergillus; fructooligosaccharide; transfructosylating; β‐D‐fructofuranosidase
• ISSN: 0145-8884; 1745-4514
• DOI: 10.1111/jfbc.12937

Aspergillus thermomutatus produces an extracellular β‐D‐fructofuranosidase when cultured in Khanna medium with sucrose as additional carbon source at 30°C under agitation for 72 hr. Addition of glucose and fructose in the culture medium affected the production of the enzyme negatively. The optimum hydrolytic activity was achieved at 60°C and pH 5.0, with half‐life (T50) of 30 hr at 50°C and 62% of its activity maintained at pH 5.0 for 48 hr. The extracellular extract containing β‐D‐fructofuranosidase was effective in producing fructooligosaccharides (FOS), mainly 1‐kestose. The highest concentration of FOS was obtained at 30°C and 60°C, indicating the existence of at least two enzymes with transfructosylating activity. At 30°C, the maximal FOS concentration was obtained from 48 to 72 hr, while at 60°C, it was achieved only at 72 hr. The best production of FOS (86.7 g/L) was obtained using 500 g/L sucrose as substrate. Practical application Fructooligosaccharides (FOS) are linear oligomers of fructose units with important applications in the food industry as sweetening agents and biopreservatives. Due to the presence of β‐glycosidic bonds, they cannot be hydrolyzed by human enzymes, allowing the use of FOS‐containing products by diabetics. FOS used in the preparation of dairy products imparts humectancy to soft baked products, lowers the freezing point of frozen desserts, provides crispness to low‐fat cookies, and provides many other advantages. Diets containing FOS can reduce the levels of triglycerides and cholesterol and improve the absorption of ions, such as Ca2+ and Mg2+. FOS also exhibit bifidogenic effect on Bifidobacterium and Lactobacillus strains in the colon. Industrially, FOS is produced during the transfructosylation reaction of sucrose catalyzed by β‐D‐fructofuranosidase. Identifying new sources of β‐D‐fructofuranosidase is an important challenge to meet its industrial demand.