The Production of Bioaroma by Auriporia aurulenta Using Agroindustrial Waste as a Substrate in Submerged Cultures

Abstract

The present study was carried out to investigate the potential of the basidiomycete Auriporia aurulenta to metabolize residues remaining from the processing of umbu, cajá, plum, and persimmon fruits for the production of natural aroma compounds using submerged fermentation. The volatile compounds obtained from the fermentation of A. aurulenta cultivated in these residues were extracted via stir bar sorptive extraction (SBSE) and analyzed using a gas chromatography-mass spectrometry (GC-MS) system. Esters and alcohols were the main compounds produced, with emphasis on the compounds 2-phenethyl acetate and 2-phenylethanol, which were mainly produced from umbu residue. The acid medium favored the production of 2-phenethyl acetate, reaching its maximum value (11.38 mg/L) on day 3.5, while higher concentrations of 2-phenylethanol were found in the basic medium, with optimal production (2.27 mg/L) on the 7th day. By varying the concentrations of pre-inoculum and residue in the optimization of this fermentation process, it was possible to double the production (24.47 mg/L) of 2-phenethyl acetate and obtain a seven times higher concentration (15.56 mg/L) of 2-phenylethanol. The diversity and expressive production of these aromatic compounds found in the fermentation media using these agroindustrial residues indicate that their use as substrates is an economical and environmentally viable alternative.

Role of Microbial Fermentation in the Bio-Production of Food Aroma Compounds from Vegetable Waste

“…The analysis of the obtained aroma bioproducts and substrates pointed out that the fermentation of umbu by-products allowed for the production of aroma compounds which were not detected in the fermentative processes carried out with the other fruit residues. In detail, (E)-β-damascenone, p-cymen-7-ol, and 1,4-p-menthadien-7-ol are three out of the four terpenoid compounds produced in all substrates [31]. 2-Phenethyl acetate was produced by all the residues, with the highest production occurring with the umbu residue.…”

“…The aroma compounds produced with persimmon residues as a substrate were responsible for citrus, green odour descriptors, such as (E)-2-octenol and 1-octanol, and myrtenyl acetate, which has a more fruity, sweet, herbal odour. The fermentation of plum residues allowed for the production of prenyl acetate and 1-octen-3-ol, which have a fruity and green odorous note, respectively [31]. The analysis of the obtained aroma bioproducts and substrates pointed out that the fermentation of umbu by-products allowed for the production of aroma compounds which were not detected in the fermentative processes carried out with the other fruit residues.…”

“…Other molecules responsible for sweet notes were also obtained in combination with other aroma compounds from the fermentation of (i) cajá and umbu residues with the fungus Auriporia aurulenta sp. [31], (ii) apple and orange pomace by Brettanomyces bruxellensis CCT 3469 [32], and (iii) rice bran with a strain of Rhizopus oligosporous sp. [33].…”

“…Agro-industrial residues from the processing of umbu (Spondias tuberosa L.), cajá (Spondias mombin L.), plum (Prunus domestica L.), and persimmon (Diospyros kaki L.) fruits have been used as a substrate for a strain of the basidiomycete fungus Auriporia aurulenta sp. in a submerged fermentation process [31].…”

“…In the fermentation tests carried out by Sandes and colleagues, the treated agroindustrial residues were used in shaking flask experiments as substrates in combination with an SNL minimum culture medium, composed of glucose, asparagine monohydrate, yeast extract, potassium hydrogen phosphate, and magnesium sulphate [31]. Following the submerged fermentation of residues of umbu, cajá, plum, and persimmon by the strain of Auriporia aurulenta sp., under the process conditions specified in Table 4, a total of 46 compounds were identified [31]. The most abundant VOCs were twenty-five esters and thirteen alcohols; four terpenoids, two aldehydes, one ketone, and one lactone were also produced.…”