Pre-treatment of corn bran for production of arabinoxylan based prebiotics

Abstract

Arabinoxylan (AX) degrades to (arabino)xylooligosaccharides [(A)XOS] through enzymatic hydrolysis. AX and (A) XOS are considered as dietary fibers and are associated with many health benefits, including immunomodulatory activity. (A)XOS includes both xylooligosaccharides (XOS) and arabino xylooligosaccharides (AXOS).

The current research aims to develop a process for production of xylan fibers, including data from the characterization of the raw material (corn bran) to the optimisation of the pretreatment process of CB by investigating the actions of sodium hydroxide (NaOH) and calcium hydroxide (Ca(OH)2) under oxidative conditions (using hydrogen peroxide) as pretreatment of corn bran in order to cause appreciable enzymatic digestibility. The best pre-treatment method was selected based on the yield, color, purity and texture of the xylan fibres, simplicity of the extraction process and scale-up possibilities.

Pretreatment of CB with Ca(OH)2 and hydrogen peroxide (H2O2) overnight at 60°C gave an extraction yield of 25.64%. The arabinose/xylose (Ara/Xyl) ratio of the obtained xylan fibers was found to be 1.69 with an ash content of 6%. The purity of arabinoxylan obtained was only 4.36%. However, when double extraction was performed following the same process, the purity of obtained arabinoxylan increased to 34.47%.

Single extraction with combined NaOH-Ca(OH)2 and H2O2 pretreatment overnight at 60°C gave an extraction yield of 55%. The arabinose/xylose (Ara/Xyl) ratio of the obtained xylan fibers was found to be 1.17 with an ash content of 21.2%. The purity of arabinoxylan obtained was 29.49%.

Popular Abstract

Digestive wellness is a mainstream consumer interest, all around the world. The human gut microbiome is composed of approximately 100 trillion microorganisms and is now considered as an organ of the body (Anon FNB News). Specific foods and dietary patterns can all influence the abundance of different types of bacteria in the gut, which in turn can affect health. Prebiotics are non-digestible fibres that act as food for the bacteria in the gut. Recent studies claim that prebiotics have the capacity to alter the gut microbiome since fibre is a key nutrient in selectively stimulating the growth and activity of certain advantageous bacteria (Valdes et al., 2018). These soluble fibers attract water during digestion and contain oligosaccharides which are sugars eaten by gut bacteria. After the gut bacteria feast upon these oligosaccharides, they release short-chain fatty acids (SCFA), which may relieve discomfort in people who have inflammatory-bowel disorders or conditions like IBS (Person 2020). Commonly known prebiotics are fructo-oligosaccharides (FOS), oligofructose, inulin, mannan-oligosaccharides (MOS), mannitol, galacto-oligosaccharides (GOS), arabinoxylan-oligosaccharides (AXOS), xylo-oligosaccharides (XOS), etc. Some novel sources of prebiotics are Inulin-rich chicory, FOS-rich Jerusalem Artichoke (JA), AXOS and XOS-rich cereal grains, β-glucans of oats etc (Samal et al., 2015).

Corn bran (CB) is a by-product left after milling corn, and is often removed from the kernel prior to processing, causing loss of nutritional quality. Studies suggest that prebiotic products can be produced from corn bran economically. However, it is complicated to recover these efficiently by only enzymatic treatment. Therefore, other methods such as mechanical or chemical pretreatments are generally applied.

For value addition of maize byproducts, the present research aims at extracting xylan from corn bran, thereby, reducing the existence of under-utilized agricultural byproducts and generating value added product. The driving philosophy in this work has been that efficient and low-cost conversion of recalcitrant, insoluble cereal plant residues. The basic motivation for the work, is that if desirable hydrolysis of corn bran is achieved, such methods and applications can most probably be directed towards other insoluble cereal residues with similar results, thereby making the approaches generic.

• author: Kaur, Manjyot
• supervisor: Javier Linares-Pastén; Peter Falck
• organization: Biotechnology (MSc); Biotechnology (M.Sc.Eng.)
• course: KBTM01 20201
• year: 2020
• type: H2 - Master's Degree (Two Years)
• subject: Technology and Engineering
• keywords: pre-treatment, alkali, arabinoxylan, prebiotics, corn, probiotics, biotechnology, bioteknik
• language: English
• id: 9015059
• date added to LUP: 2020-06-12 16:48:42
• date last changed: 2020-06-12 16:48:42