Utilization of agro-industrial by-products in Monascus fermentation: a review

The Monascus fermentation industry has gained global attention. Its key products, i.e., pigments, functional food ingredients, food supplements, and medicinal use, are growing in the world’s market. Efforts to find the cost-effective substrate for Monascus fermentation have remained the target. This paper aimed to appraise the utilization of agro-industrial by-products (cereal, starchy tuber and root, legume, fruit, and coffee processing) as a cost-effective substrate for Monascus fermentation. The specific objective was to review the by-products pre-treatment, the fermentation process, product yield, and the bioactivity of the fermented products. Among all the by-products that could be used as the fermentation substrate, cereal brans do not need pre-treatment, but others need a suitable pre-treatment step, e.g., cassava peel, okara, and jackfruit seed to list a few, that need to be powdered beforehand. Other substrates, such as corn cob and durian seed, need soaking and size reduction through the pre-treatment step. During fermentation, Monascus produce many pigments, monacolin K, associated with rise in phenolic and flavonoid contents. These products possess antioxidant, antihypercholesterol, antidiabetes, and antiatherosclerosis activities which underpin their health significance. In conclusion, we report in this review the agro-industrial by-products which have potential prospects for pigments, functional food ingredients, food supplements, and therapeutic usages produced from Monascus fermentation.

Feruloylated Arabinoxylan and Oligosaccharides: Chemistry, Nutritional Functions, and Options for Enzymatic Modification

Cereal brans and grain endosperm cell walls are key dietary sources of different types of arabinoxylan. Arabinoxylan is the main group of hemicellulosic polysaccharides that are present in the cell walls of monocot grass crops and hence in cereal grains. The arabinoxylan polysaccharides consist of a backbone of β-(1→4)-linked xylopyranosyl residues, which carry arabinofuranosyl moieties, hence the term arabinoxylan. Moreover, the xylopyranosyl residues can be acetylated or substituted by methyl-glucuronic acid. The arabinofuranosyls may be esterified with a feruloyl group. Feruloylated arabinoxylo-oligosaccharides exert beneficial bioactivities via prebiotic, immunomodulatory, and/or antioxidant effects. New knowledge on microbial enzymes that catalyze specific structural modifications of arabinoxylans can help us understand how these complex fibers are converted in the gut and provide a foundation for the production of feruloylated arabinoxylo-oligosaccharides from brans or other cereal grain processing sidestreams as functional food ingredients. There is a gap between the structural knowledge, bioactivity data, and enzymology insight. Our goal with this review is to present an overview of the structures and bioactivities of feruloylated arabinoxylo-oligosaccharides and review the enzyme reactions that catalyze specific changes in differentially substituted arabinoxylans. Expected final online publication date for the Annual Review of Food Science and Technology, Volume 12 is March 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.