Hydrodistillation time for determining the yield and chemical composition of the essential oil from Humulus lupulus L. var. Comet cultivated under subtropical conditions

Abstract

Hop cultivation is expanding in subtropical regions, but quality assessment methods are still based on studies conducted under temperate climate conditions, which may compromise the accuracy of analyses. The ASBC Hops-13 method, although widely used and reliable, requires long extraction times (4 to 7 hours) and expensive equipment, limiting its application in low-resource laboratories and delaying post-harvest analyses. This poses an economic barrier for emerging producers like Brazil, highlighting the need for more accessible and locally adapted alternatives. This study evaluated the effect of hydrodistillation time on the yield and chemical composition of essential oil from Comet hop cones grown under subtropical conditions, selected for their quality in terms of aroma and bitterness compounds. A completely randomized design was used with four distillation durations: 60, 120, 180, and 240 minutes. Essential oils were analyzed using GC-FID and GC-MS. Results showed that hydrodistillation time significantly affected both yield and chemical composition. The 120-minute extraction was efficient, with a yield comparable to the 180-minute treatment, while 60 minutes presented lower means. A total of 21 compounds were identified, 12 of which were major constituents. Significant variation was found in β-myrcene, linalyl isobutanoate, and selina-3,7(11)-diene. Longer distillation times increased the relative abundance of heavier compounds, but the overall chemical profile remained stable. The herbal aromatic descriptor predominated across all durations, with similar sensory profiles observed at 120, 180, and 240 minutes.