Headspace Volatile Organic and Phenolic Compounds in Elderflowers and Elderflower Teas of Blue Elderberry (Sambucus nigra ssp. cerulea)

Abstract

Elderflower products have become more popular in the U.S., yet most are still made from European-grown flowers. Flowers of the subspecies native to the western region of North America (Sambucus nigra ssp. cerulea) were investigated for the first time. The phenolic compounds were evaluated in ethanol/water extracts of fresh and dry flowers (either homogenized or as the intact flower) and in hot water extracts (teas) of the dry, intact flowers. Fresh homogenized flowers had significantly higher levels of phenolic compounds than the other preparations. The predominant flavonols identified were isorhamnetin-3-O-rutinoside (ranging from 32.48 to 78.73 mg g–1 dry weight) and rutin (ranging from 3.20 to 10.01 mg g–1 dry weight). Total phenolic levels in elderflower teas were 23.98 ± 0.838 μg g–1 and increased by 47% over a 20 min infusion time. Volatile profiles were measured in fresh and dried flowers and in teas made from these flowers. One of the prevalent compounds in fresh flowers and tea made with fresh flowers that appears unique to this subspecies is methyl eugenol (16.90 and 20.14% of the relative peak area, respectively). Drying the flowers significantly changed the headspace volatile profile. Levels of methyl eugenol were reduced to 2.46% of the relative peak area, whereas 3-hexen-1-ol levels were increased. Tea made from the fresh and dry flowers had relatively high levels of straight-chain aldehydes as compared to the flowers. Elderflowers of S. nigra ssp. cerulea can be used to make differentiated elderflower products for consumers interested in bioactive compounds and unique sensory profiles.