Identification of aroma-active compounds in milk by 2-dimensional gas chromatography-olfactometry-time-of-flight mass spectrometry combined with check-all-that-apply questions.

Understanding consumers' sensory preferences for dairy products is essential. This study employed sensory analysis and instrumental techniques to analyze the flavor of pasteurized milk and UHT milk. There were 6 milk samples with similar fat content (4.0-4.6 g/100 mL) and protein content (3.2-3.8 g/100 mL). Sensory data from consumer tests was collected using check-all-that-apply (n = 100) and 9-point hedonic preferences. Research showed that Chinese consumers could distinguish the flavor of the 2 types of milk, and UHT milk showed a higher preference score, which may be due to the more pronounced milky flavor and sweet taste of UHT milk. A total of 48 aroma-active compounds were sniffed through 2-dimensional gas chromatography olfactometry time-of-flight MS, among which 11 were determined as key aroma-active compounds. Correlation analysis showed that milky odor, sweetness, and aftertaste-milky were positively correlated with γ-dodecalactone and γ-nonanolactone. Cooked and oxidized taste were positively correlated with 1-octen-3-ol and E-2-octenal. This study is important for developing Chinese dairy products and exporting dairy products to China by multinational companies.