Microbial ecology and functional coffee fermentation dynamics with Pichia kudriavzevii

• Published in: Food microbiology 2022-08, Vol.105, p.104012-104012, Article 104012
• Main Authors: S R, Shankar, H P, Sneha, Prakash, Inderjit, Khan, Mahejibin, H N, Punil Kumar, Om, Hari, Basavaraj, K., Murthy, Pushpa S.
• Format: Article
• Language: English
• Subjects: Arabica coffee; Coffee - chemistry; Coffee quality; Fermentation; Flavoring Agents - metabolism; Metabolites; Metagenomics; Pichia - metabolism; Starter culture; Sugars
• ISSN: 0740-0020; 1095-9998
• DOI: 10.1016/j.fm.2022.104012

Specialty coffee can be developed by the application of explicit microorganisms or starters to obtain desired fermentation. In the present study, natural fermentation (NF) of Arabica coffee was carried out spontaneously, the other set was inoculated with Pichia kudriavzevii (Y) starter culture (isolated, identified and mass cultured). The effect of microbial fermentation, metagenomics, production of functional metabolites, volatiles and their sensorial aspects were studied. The bioprocess illustrated cohesive interface of coffee nutrients and microbial communities like Mycobacterium, Acinetobacter, Gordonia, etc., in NF, Lactobacillus and Leuconostoc were prevailing in Y. The Pichia and Rhodotorula dominated in both the groups. The bioactivity of bacteria and fungi induced complex changes in physicochemical features like pH (4.2–5.2), Brix° (9.5–3.0), and metabolic transition in sugar (3.0–0.7%), alcohol (1.4–2.7%), organic acids modulating flavour precursors and organoleptics in the final brew. In the roasted bean, Y exhibited higher sugar (42%), protein (25%), polyphenol (3.5%), CGA (2.5%), caffeine (17.2%), and trigonelline (2.8%) than NF. The volatile profile exhibited increased flavour molecules like furans, ketones, and pyrazines in Y, besides lactone complexes. The organoleptics in Y were highlighted with honey, malt and berry notes. P. kudriavzevii coffee fermentation could be beneficial in specialty coffee production and enhancement of distinct characteristic flavours. [Display omitted] •Pichia kudriavzevii is a promising starter in coffee fermentation to produce an exceptional brew.•Starter modulates the coffee fermentation elucidating the functional microbial biosynthesis and metabolic pathways.•P. kudriavzevii regulates the coffee bionetwork to synthesize flavour compounds and their derivatives.•Developed enhanced aromatic and flavours in the brew due to the presence of furans and lactones.