In the world of tea production, foam can be a significant challenge, affecting both the aesthetic appeal and sensory experience of tea beverages. A recent study published in *Shipin Kexue* (which translates to *Food Science*) has shed light on how silicone-based anti-foaming agents can influence the aroma and flavor of oolong tea, offering valuable insights for the industry.
Led by ZHANG Weiming from the Anxi College of Tea Science at Fujian Agriculture and Forestry University, the research team employed a combination of sensory evaluation, electronic nose technology, and headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) to assess the impact of different concentrations of silicone-based anti-foaming agents on Rougui oolong tea beverages.
The study found that low and medium concentrations of the anti-foaming agent effectively reduced foam height and shortened the time it took for the foam to collapse. Interestingly, the timing of the anti-foaming agent’s addition also played a crucial role. “The effect was more pronounced when the anti-foaming agent was added before foam generation rather than after,” noted ZHANG Weiming, highlighting the importance of timing in the application process.
However, the researchers also discovered that adding too much anti-foaming agent could lead to undesirable outcomes. Excessive amounts caused the tea infusion to become turbid and increased astringency and off-flavors, ultimately deteriorating the overall quality of the beverage.
The electronic nose sensors provided significant insights, with notable differences in responses for sensors W5S (nitrogen oxides), W1S (short-chain alkanes), W1W (inorganic sulfides), and W2W (aromatic components and organic sulfides) among the different treatment groups. This suggests that the anti-foaming agent can influence the chemical composition of the tea beverage.
The HS-SPME-GC-MS analysis identified a total of 110 aroma compounds, with 26 key differential compounds selected through orthogonal partial least squares-discriminant analysis (OPLS-DA) and the Kruskal-Wallis H test. The relative odor activity value (ROAV) analysis revealed that the contents of aroma components such as linalool, dihydrolinalool, phenylethyl alcohol, and trans-nerolidol significantly declined with increasing concentrations of the anti-foaming agent. This inhibition of aroma component release could alter the overall aroma profile of the tea.
Based on the anti-foaming efficacy and sensory balance, the optimal concentration of the anti-foaming agent was determined to be between 0.005–0.025 g/kg. This concentration effectively controls foaming while preserving the flavor, offering a balanced solution for tea producers.
The implications of this research are substantial for the tea industry. By understanding how anti-foaming agents influence the aroma and flavor of tea beverages, producers can make more informed decisions to enhance product quality. “This study helps elucidate the mechanism by which anti-foaming agents influence tea beverage aroma, providing theoretical insights for quality control and aroma optimization in tea beverage production,” said ZHANG Weiming.
As the tea industry continues to evolve, such scientific advancements will be crucial in maintaining and improving the sensory qualities of tea beverages. The research published in *Shipin Kexue* not only highlights the importance of precise application of anti-foaming agents but also paves the way for future innovations in tea production technology.