Using instrumental and sensory analysis to investigate the flavor of different cucumber varieties and the impact on lemon flavored water
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Cucumber has unique flavors including green, fresh, fatty, and melon notes. Refreshing concept is trendy in the beverage market, while sugar reduction in processed foods and beverages is a prominent global trend in recent years. However, few studies have focused on the contribution of cucumber flavor to refreshing perception and its role in sugar-reduced beverage. The objective of this study was to investigate cucumber flavor composition and the impact on refreshing perception and other sensory properties of sugar- reduced lemon flavored water. An online survey was conducted to investigate the consumers’ expectation and experience on flavored water. Responses from 906 participants indicated flavored water was ranked 4th most popular beverage. Lemon flavor was the most popular flavor (52.1%), while sugar was the major concern (47.4%) by consumers. Refreshing perception was selected as the most important function (87.4%). Therefore, sugar-reduced lemon flavored water with refreshing perception was chosen as this thesis research topic. Solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) was used to analyze volatiles in four types of cucumbers, resulting in a total of 98 volatiles, with dominant volatiles of (E,Z)-2,6-nonadienal and (E)- 2-nonenal. According to the result, a general cucumber flavor was formulated with 10 most iv important cucumber volatiles. The impact of cucumber flavor on sugar-reduced lemon flavored water was investigated using descriptive sensory analysis and consumer test. Six lemon flavored water with four sugar levels were formulated: 0% (full sugar: 7%), 50%, 80%, 100%, 50% and 80% reduction with cucumber flavor added, respectively. A total of 12 flavor descriptors were developed by 12 trained panelists. Significant difference (ANOVA, p<0.05) of the sensory attributes across all samples were observed except lemon note. The lemon flavored water (zero reduction) dominated with juicy, lemon, refreshing, lemonade, and sweet flavor notes. The flavor profiles changed along with sugar reduction. The lemon flavored water lost the richness and balance as sugar reduced, while irritate and bitterness showed up when sugar was reduced to 100%. However, up to 80% sugar reduction, the flavor was still pleasant. Added cucumber flavor increased fresh, green, cucumber, and refreshing perception in both 50% and 80% reduction; more effective in 80% reduction (t-test, p<0.05). The acceptance of six lemon flavored waters was evaluated by 100 consumers using 15 questions. Consumer perceived significant difference of all attributors across all samples (ANOVA, p<0.05). The overall liking of five flavored waters, except 100% reduction, was rating above 5 (either like nor dislike) out of a 9-point hedonic scale, indicating these formulated flavored waters were acceptable. Adding cucumber flavors had impact on overall flavor and refreshing intensities, but no impact on hedonic levels (t-test, p<0.05). Knowledge gained in this study could give insight to sugar-reduced drinks for the beverage industry.