Bacuri and macaxeira waste: physical-chemical characterization and production of coconut bioaroma by solid-state fermentation

Abstract

Agro-industrial waste is considered a global concern. Many of these residues are composed of considerable amounts of lipids and starch that can potentially be applied in bioprocesses, as is the case with residues from the bacuri fruit (Platonia insignis Mart.) and sweet cassava (Manihot esculenta Crantz), practically unexploited in the bioproduction of aromas. This work aimed to characterize these residues and evaluate the bioproduction of coconut aroma 6-pentyl-α-pyrone from solid-state fermentation using the fungi Trichoderma harzianum. The waste underwent characterization. Fermentations were conducted under different humidification conditions (water, nutrient solution without additives, and nutrient solutions with glucose or sucrose) for nine days. Aromatic compounds were extracted by solid-phase microextraction and subsequently quantified by gas chromatography. Analyses with bacuri residue revealed the presence of some compounds with nutritional potential for the fungus. Still, the inhibition halo detected for Trichodermaproved others, such as resinous derivatives that were probably responsible for the lack of growth and bioproduction. In sweet cassava, the compounds detected were not growth inhibitors and had low aroma production, not exceeding 7 ppm (weight/weight). Strategically, these residues were mixed and, in the presence of a nutrient solution with sucrose, a maximum production of 202.46±1.30 ppm (w/w) of 6-pentyl-α-pyrone was achieved, proving an excellent alternative. Cassava probably served as an environment for easy germination of fungal spores and bacuri, as an important source for bioexploitation of nutrients, especially lipids, resulting in increased production of 6-pentyl-α-pyrone.