Volatile profile modifications of quinoa (Chenopodium quinoa) after Aspergillus oryzae fermentation and autoclaving as a strategy for novel food ingredient development

The increasing demand for sustainable food ingredients underscores the significance of quinoa (Chenopodium quinoa) as a promising raw material, owing to its exceptional nutritional profile and compatibility with microbial fermentation processes. This study evaluated changes in quinoa's volatile profile after short solid-state fermentation (1 – 3 days) with Aspergillus oryzae ATCC 10124 and autoclaving, to assess its potential as a food ingredient. For fermentation, 10 g of quinoa were placed in 50 mL Erlenmeyer flasks, autoclaved at 121 °C for 15 min. An abiotic control was prepared under the same conditions without inoculation. Other flasks received 1000 µL of A. oryzae ATCC 10124 spore suspension (3.8 × 10^7 spores/mL, sterile gauze-filtered) and incubated at 25 °C. After 1, 2, and 3 days, samples were either analyzed directly or autoclaved again to produce fermented–autoclaved treatments. Volatile compounds were extracted using headspace solid-phase microextraction (SPME) with a DVB/CAR/PDMS fiber and analyzed by gas chromatography–mass spectrometry (GC–MS). Two grams of sample and 6.0 mL of 20% w/v NaCl were placed in a 20 mL glass vial with a screw cap and PTFE-silicone septum, homogenized, and incubated at 50°C for 30 minutes. The fiber was desorbed in the GC injector for 10 minutes at 230°C. Separation used a SupelcoWAX 10 column with helium, following a temperature program from 35°C to 250°C. Mass spectra were collected in TIC mode (m/z 40–280). Qualitative analysis revealed apparent differences between the control and fermented samples. The abiotic control (autoclaved quinoa without inoculum) showed only simple volatiles associated with thermal degradation, with low sensory relevance. Fermentation progressively generated more diverse volatiles: hydrocarbons and amines on day 1, ketones and acids on day 2, and sulfur compounds (e.g., thiolanes) by day 3, indicating the establishment of metabolic activity and the formation of novel aroma notes. When fermentation was followed by autoclaving, additional transformations were observed: early appearance of esters and furans on day 1, prominent fruity esters (e.g., vinyl butyrate) and sulfur volatiles (e.g., carbon disulfide) on day 2, and intense contrasts between fruity esters and sulfur compounds such as methanethiol on day 3. In conclusion, short fermentation of quinoa with A. oryzae ATCC 10124 changed its volatile profile, and autoclaving increased ester and sulfur compounds, which could influence sensory properties. These findings suggest that the integration of fermentation and subsequent processing could modify quinoa’s aroma profile and potentially broaden its applications as a functional food ingredient.