Abstract
Throughout human history, flaxseed (πΏπππ’π π’π ππ‘ππ‘ππ π πππ’π L.) has served diverse purposes. In recent decades, its nutritional benefits have been widely studied, primarily because of its high linolenic acid content, which is believed to offer notable health benefits such as anti- inflammatory and cardiovascular positive effects. Due to these health benefits, flaxseed oil extraction has also increased in response to the market demand. Oil extraction yields flaxseed meal as a by-product. Flaxseed meal is a nutritionally rich material, but is underutilised due to its high cyanogenic glycoside content, which can be released as hydrogen cyanide upon hydrolysis. This study investigated microbial fermentation as a biological detoxification strategy for flaxseed meal while evaluating its effects on nutritional composition and bioactive properties. Flaxseed meal derived from New Zealand flaxseed, for which limited detoxification data are currently available, was fermented using πΏπππ‘ππππππππ’π πππππ‘πππ’π, πΏπππ‘ππππππππ’π π ππππ, and ππππβπππππ¦πππ πππππ£ππ πππ under varying fermentation times, particle sizes, and addition of sucrose. Detoxification was associated with microbial activity and enzymatic hydrolysis, likely mediated by Ξ²-glucosidase activity and enhanced enzyme-substrate interactions during fermentation.
Fermentation reduced total cyanogenic glycoside levels, which were quantified, with reductions ranging from approximately 30% to 55% depending on the treatment applied, although not complete detoxification was visible. Individual cyanogenic glycosides were quantified to assess detoxification in fermented flaxseed meal, with the π. πππππ£ππ πππ-treated samples excelling, as complete detoxification of the individual glycosides had occurred. Proximate composition and amino acid profiles of the untreated and treated samples were analysed to evaluate nutritional modifications, with results varying across treatments. The crude protein content increased in the π. πππππ£ππ πππ small particle size sample from 34 to 35.7%. The amino acid profiles showed modest increases, particularly in alanine, aspartic acid, and glutamic acid, in the microbial-treated samples. Bioactive responses were assessed by analysing total phenolic content, phenolic acid profiling, and antioxidant activity using DPPH, ABTS, and FRAP assays. The addition of sucrose did not significantly enhance the overall detoxification of CGs in flaxseed meal (p > 0.05).
Changes in the total phenolic content and individual phenolic acids were treatment-dependent, indicating both the release of bound phenolics and potential microbial conversion. Antioxidant activity varied across assays, highlighting differences in radical scavenging and reducing capacity among the resultant extracts from the various treatments. Overall, this study demonstrates that microbial fermentation is an effective, food-grade approach for reducing cyanogenic glycosides in flaxseed meal while modifying its nutritional and functional properties, supporting its potential value as a functional food ingredient rather than low-value animal feed.