Blue elderberry (Sambucus nigra ssp. cerulea), a subspecies native to the western United States, is frequently planted in farm hedgerows in California for their ecological benefits and they thrive in challenging environments produced by climate change. Key properties of blue elderberry were evaluated for the first time over two growing seasons to better understand this subspecies compared to those typically used in food, beverages, and supplements. The soluble solids, titratable acidity, and pH of the blue elderberry were similar to common elderberry subspecies (S. nigra ssp. nigra and S. nigra ssp. canadensis). Total monomeric anthocyanin levels were about half to a quarter of the level compared to other subspecies, whereas total phenolic content was similar to that of other elderberry subspecies. Higher levels of flavonols (i.e., rutin and isorhamnetin-rutinoside) were found in the blue elderberry compared to other subspecies. Two phenolic compounds, 5-hydroxypyrogallol hexoside and protocatechuic acid dihexoside, were tentatively identified in the blue elderberry using accurate mass QTOF-MS/MS and are unique to this subspecies. Data demonstrate that this subspecies grown in California can be used in for food and beverage applications like other elderberry subspecies.

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.