From the forest to the plate – hemicelluloses, galactoglucomannan, glucuronoxylan, and phenolic-rich extracts from unconventional sources as functional food ingredients

This study aimed to characterise pressurised hot water (PHW) extracts from nonconventional sources of functional carbohydrates and phenolic compounds in terms of antioxidant capacity, antiviral activity, toxicity, and human erythrocytes’ protection antidiabetic potential. PHW extracts of Norway spruce bark (E1 + E2) and Birch sawdust (E3 + E4) contained mostly galactoglucomannan and glucuronoxylan. In contrast, samples E5 to E9 PHW extracted from Norway spruce, and Scots pine bark are rich sources of phenolic compounds. Overall, phenolic-rich extracts presented the highest inhibition of α-amylase and α-glucosidase and protection against stable non-enveloped enteroviruses. Additionally, all extracts protected human erythrocytes from hemolysis. Cell-based experiments using human cell lines (IMR90 and A549) showed extracts’ non-toxic in vitro profile. Considering the relative toxicological safety of extracts from these unconventional sources, functional carbohydrates and polyphenol-rich extracts can be obtained and further used in food model

Digested galactoglucomannan mitigates oxidative stress in human cells, restores gut bacterial diversity, and provides chemopreventive protection against colon cancer in rats

Galactoglucomannan (GGM) is the predominant hemicellulose in coniferous trees, such as Norway spruce, and has been used as a multipurpose emulsifier in the food industry. In vitro digestion with a cellular antioxidant activity assay was performed to determine the bioaccessibility and antioxidant activity of phenolic compounds, and the behaviour of GGM on in vivo experimental assay against induced colon cancer. The results showed that digestion decreased the bioaccessibility and antioxidant capacity of phenolic compounds. Cellular analysis did not support these findings once an antioxidant effect was observed in human cell lines. GGM attenuated the initiation and progression of colon cancer, by reducing the foci of aberrant crypts in rats, and modified the intestinal bacterial microbiota (disrupting the balance between Firmicutes and Bacteroidetes phyla). Thus, GGM provided chemopreventive protection against the development of colon cancer and acted as an intracellular antioxidant agent.</p