Characterization of the potent odorants in Tibetan Qingke Jiu by sensory analysis, aroma extract dilution analysis, quantitative analysis and odor activity values.

Tibetan Qingke Jiu is the most important alcoholic beverage in the daily life of Tibetan people due to its unique flavor and rich nutrients. In this study, the aromatic characteristics of Qingke Jiu were studied by sensory analysis, aroma extract dilution analysis (AEDA), quantitative analysis, and odor activity values (OAVs). Sensory evaluation demonstrated that Qingke Jiu had fruity, cooked potato, honey, sour, sweet, and caramel-like aroma. A total of 66 aroma compounds were identified by AEDA and gas chromatography-mass spectrometry, with flavor dilution (FD) factors ranging from 4 to 2048. Among them, methional, acetic acid, ethyl butanoate, phenylacetaldehyde and ß-phenylethanol appeared with the highest FD factors. The concentration of these aroma-active compounds was further quantitated by combination of four different quantitative measurements, and 17 odorants had concentrations higher than their odor thresholds. Based on the OAVs, phenylacetaldehyde, ß-phenylethanol, ethyl phenylacetate, sotolon, furaneol, methional, methionol, γ-nonalactone, ethyl 2-methylbutanoate, ß-damascenone, ethyl 3-methylbutanoate, ethyl acetate, ethyl butanoate, and acetic acid could be potentially important to the overall aroma profile of Qingke Jiu.

Impact of processing on odour-active compounds of a mixed tomato-onion puree.

Gas chromatography-olfactometry revealed thirty-two odour-active compounds in a heat-processed tomato-onion puree, among which twenty-seven were identified by gas chromatography-olfactometry-mass spectrometry (GC-O-MS) and comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC×GC-TOF MS). Based on the results of two olfactometric methods, i.e. detection frequency and aroma extract dilution analysis, the most potent aroma components include: dipropyl disulfide, S-propyl thioacetate, dimethyl trisulfide, 1-octen-3-one, methional, dipropyl trisulfide, 4,5-dimethylthiazole, 2-phenylacetaldehyde and sotolone. Processing of mixed vegetable systems can add complexity in their aroma profiles due to (bio)chemical interactions between the components. Therefore, the impact of different processing steps (i.e. thermal blanching, all-in-one and split-stream processes) on the volatile profile and aroma of a mixed tomato-onion puree has been investigated using a GC-MS fingerprinting approach. Results showed the potential to control the aroma in a mixed tomato-onion system through process-induced enzymatic modulations for producing tomato-onion food products with distinct aroma characteristics.