Fatty Acids Are Responsible for the Discrepancy of Key Aroma Compounds in Naturally Dried Red Goji Berries and Hot-Air-Dried Red Goji Berries.

Red goji berries, reputed worldwide as "superfruit", are commonly marketed after natural drying or hot-air drying. A sensomics approach was applied to the aroma analysis of red goji berries under two drying methods. Fifty-two aroma-active compounds were screened and identified by aroma extract dilution analysis (AEDA) coupled with gas chromatography with olfactometry (GC/O). The contents and the odor activity values (OAVs) of 49 aroma-active compounds were determined. Acetic acid was the predominant aroma compounds in both berries. Meanwhile, the key aroma compounds in both berries were (E)-2-nonenal, (Z)-4-heptenal, 3-methyl-2,4-nonanedione, hexanal, etc., which were lipid derivatives. Natural drying promoted the formation of some aldehydes that exhibited green and fatty notes. Hot-air drying facilitated the production of ketones with hay-like and cooked apple-like odor attributes due to the thermal reaction. The fatty acid patterns between naturally dried and hot-air-dried red goji berries differed not significantly and were dominated by linoleic acid, oleic acid, palmitic acid, etc. The knowledge of the impacts of different drying processes on the aroma quality in red goji berries is beneficial for the quality control and optimization of dried red goji berries.