Characterization of the aroma profile of quinoa (Chenopodium quinoa Willd.) and assessment of the impact of malting on the odor‐active volatile composition

Abstract

Background: Quinoa (Chenopodium quinoa Willd.) is a gluten-free pseudocereal, rich in starch and high-quality proteins. It can be used as a cereal. Recently, a variety of nontraditional food products were developed; however, the sharp bitterness and the earthy aroma of unprocessed quinoa interfered with the acceptance of these products. Malting of cereals is known to improve their processing properties and enhance their sensory quality. To evaluate the acceptance and potential of quinoa malt as a raw material for beverage production, malt quality indicators (e.g., soluble protein) and the aroma profiles of different quinoa malts were compared.Results: Initial sensory assessment of quinoa in its native and malted state identified differences in their aroma profiles and revealed that pleasant nutty and caramel aromas were formed by malting. Subsequently, three complementary isolation techniques and gas chromatography-olfactometry/mass spectrometry (GC-O/MS) were used for volatile analysis. Instrumental analysis detected 34 and 62 odor-active regions in native quinoa and quinoa malt, respectively. In the second part, storage and the impact of three malting parameters on volatile formation were examined. By varying the malting parameters, seven additional odor-active malting byproducts were revealed.Conclusion: Three naturally occurring methoxypyrazines were identified as important contributors to the characteristic quinoa aroma. In all fresh quinoa malts a similar number of volatile compounds was perceived but their intensity and composition varied. Higher germination temperature promoted the formation of lipid oxidation products. Fatty smelling compounds and carboxylic acids, formed during storage, were classified as aging indicators of quinoa malt.

Influence of germination and roasting on the characteristic volatile organic compounds of quinoa using sensory evaluation, E-nose, HS-GC-IMS, and HS-SPME-GC-MS

“…Pyrazine is mainly formed by the reaction between amino ketones ( Wei et al, 2020 ). It is reported that pyrazine is an important volatile compound for adding roasting flavor to foods ( Almaguer et al, 2023 ). 2,3-dimethyl pyrazine produces caramel, cocoa, peanut butter, and roasted aromas, playing an important role in quinoa aroma.…”

“…2-mercaptoethanol and tetrahydrofurfuryl alcohol produce a typical nutty aroma, which were only detected in the RGQ samples. Esters contribute to the characteristic flavor of most grains, producing ester, floral, and fruit aromas ( Almaguer et al, 2023 ). Methyl isobutyrate (flower, fruit) and hexyl formate (fruit) were also only detected in the RGQ samples.…”

“…Typically, unprocessed quinoa has unpleasant flavors of grass and earth. In this regard, germination could alter the sensory and nutritional aspects of the grain, serving as a potential method for reducing off-flavors ( Almaguer, Kollmannsberger, Gastl, & Becker, 2023 ). Previous studies have reported the effect of various processing methods, such as cooking and fermentation, on the flavor of quinoa ( Brito et al, 2015 ; Li et al, 2018 ).…”

Daily assessment of malting‐induced changes in the volatile composition of barley (Hordeum vulgare L.), rye (Secale cereale L.), and quinoa (Chenopodium quinoa Willd.)

“…High and low concentrations are shown in black and white, respectively. Odor descriptions as perceived at the sniffing port are listed on the right (Almaguer et al., 2023). Rectangles on the left grouped compounds by chemical class; both furans and the lactone included in others.…”

“…Unlike barley, all alcohols increased until the last day of germination in rye, except octan‐1‐ol. Similar to barley, 3‐methylbutan‐1‐ol, 2‐phenylethan‐1‐ol, hexan‐1‐ol, and ( E )‐hex‐2‐en‐1‐ol were the most abundant alcohols in germinating rye, these contribute green, grassy, and floral notes (Almaguer et al., 2023). In quinoa, all alcohols increased with germination, except ( E )‐hex‐2‐en‐1‐ol.…”