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Characteristics and bioactive properties of mannooligosaccharides derived from agro-waste mannans

Jana, Uttam Kumar, Kango, Naveen
International journal of biological macromolecules 2020 v.149 pp. 931-940
Aspergillus oryzae, Fourier transform infrared spectroscopy, Lactobacillus, agricultural wastes, antioxidant activity, beta-mannosidase, coconut meal, colon, cytotoxicity, functional foods, gel chromatography, guar gum, human cell lines, hydrolysates, ingredients, iron, locust bean gum, mannans, neoplasm cells, nuclear magnetic resonance spectroscopy, palm kernel cake, prebiotics, probiotics, protein kinase C, sugars
Mannooligosaccharides (MOS) were derived using Aspergillus oryzae β-mannanase (ManAo) from different mannan-rich agro-wastes, palm kernel cake (PKC), guar gum and copra meal (CM). Guar gum (GG) released higher amount of MOS (56.31% w/w) from which purification of mannobiose (0.68 mg) and mannotriose (1.26 mg) was demonstrated using size-exclusion chromatography. FTIR analysis of mannan hydrolysates showed characteristic peaks in 1200–900 cm⁻¹ region indicating the presence of MOS. ¹H &¹³C NMR spectra showed presence of anomeric sugar forms of MOS in different mannan hydrolysates. MOS from locust bean gum and guar gum had both α- and β-anomers while PKC and CM had only α-anomer. Growth promotional activities of different MOS were demonstrated using two probiotic Lactobacilli. Besides, enzymatically derived MOS also showed metal (Fe²⁺) chelating and anti-oxidant activities, wherein best anti-glycating agent was evaluated as MOS from PKC. PKC derived MOS showed highest cytotoxicity (74.19%) against human colon adenocarcinoma cell line (Caco-2). This study demonstrated the prebiotic potential of agro-waste derived MOS and possibility of their utilization as a functional food ingredient.