Unfortunately, that study did not include any growing information about the elder flowers or the concentration of the phenolic compounds in the extract, which would have helped other researchers replicate and expand on the results. While there have been promising studies on the impact of elderberry and elderflower extracts to combat illness and disease, more in vivo studies and clinical trials should be performed to better understand the mechanisms of the bioactivity as well as to determine which compounds are responsible for the bioactivity, particularly in the lesser-known subspecies canadensis andcerulea. This can better inform people involved with the cultivation of elderberry to select for varieties that have the compounds of interest.The market for herbal supplements has been growing in the recent decade and immune system-supporting supplements had a huge spike in sales during the COVID-19 pandemic. Elderberry products are a popular option of alternative medicine in hopes of improving and protecting health. Beverages are a popular use of the elderberry, including syrup or other tonics made by soaking the berries in water or alcohol. It can also be found as an ingredient in various kombuchas, juices, energy drinks, wine, and tea. Elderberry is typically mixed with a variety of other ingredients, including but not limited to ginger, honey, echinacea, and other spices. More recent products using elderberry include gummies typically marketed as health supplements, lozenges, tablets, and powdered berries especially as part of a drink mix. Elderberries are also frequently used in jams and jellies. Pomace, the byproduct of juicing, has been studied for its benefits when incorporated into other products just as baked goods. Beyond its potential for bio-active products to benefit consumers, tower garden elderberry can also be used as a natural food dye due to the high concentration of anthocyanins , which can be used in place of artificial red or purple food dyes, particularly in acidic foods.

Its application in edible films has recently been investigated, explored various bio-polymers that could retain the phenolic compounds of elderberry in the film so that they can remain active to protect foods. Active edible films can be an effective solution to reduce plastic packaging and food waste due to spoilage.Cosmetic and skin care applications are also an area of interest, 37 and current products on the market that include elderberry include lip color, toner, face mask, and Epsom salt.Future chapters will focus on evaluating the blue elderberry and elderflower for their composition. Herein, the data available on the other elderberry subspecies of interest are summarized to provide a basis of the expected composition as well as information to compare the subspecies for their composition. Elderberries have a high amount of water, at about 80%. The main sugars in elderberry are glucose and fructose, with some small amounts of sucrose. Sorbitol was also measured, which was very minor compared to the other three sugars and was seen in the highest concentrations in the wild elderberry. Citric acid is the main organic acid in elderberry, with malic acid the next highest acid. Small amounts of shikimic, tartaric, and fumaric acid have been measured in elderberry as well. Only data on European elderberry is available for microcon-stituents such as vitamins, minerals, fatty acids, and amino acids. Vitamins found in elderberry include various B vitamins, vitamin C, and vitamin E.The main minerals are magnesium, calcium, and potassium. Because studies of these micro-nutrients have only been performed on the European elderberry, it is important for further work to include other subspecies, including the American and blue elderberry so that better comparisons can be made.An important group of bio-active compounds found in fruit and vegetables is phenolic compounds, which consist of one or more phenolic groups .

Types of phenolic compounds include phenolic acids and flavonoids; flavonoids can be further separated into groups such as anthocyanins, flavonols, flavan-3-ols, and flavones. Phenolic compounds may have some biological activity, although bio-availability can be very low. A common, albeit imperfect, way to measure phenolic content of elderberries is using a colorimetric method like Folin-Ciocalteu which can measure a complex that forms between phenolic compounds and molybdenum-tungsten at 765 nm. Because this method measures all reducing agents in the matrix, reducing sugars and ascorbic acid will also react and increase the absorption thus inflating the total phenolic content . Standard curves are typically constructed using gallic acid, hence the units for TPC are gallic acid equivalents . TPC in European elderberries can vary greatly but reported values include 461 ± 121 49 and 683 ± 49. In American elderberry, TPC has been reported to be 390 ± 56 50, 593 ± 70. One study has included blue elderberry grown in Slovenia, which had a TPC of 416 ± 31. However, because of the imprecise nature of this assay, it is important to identify and measure the concentration of each phenolic compound present whenever possible, the results of which is explored in the following sections.Anthocyanins are water-soluble pigments in plants, and they give elderberries their blue purple hue. Total monomeric anthocyanin content is typically measured using the pH differential method, which takes advantage of the change in light absorption of anthocyanins insolutions with different pH and the unit is typically cyanidin glucoside equivalents . Analysis of the phenolic compounds via high performance liquid chromatography with UV-Visible light detection or with mass spectrometry have elucidated a variety of molecules present in the European elderberry. Anthocyanins, a type of flavonoid and popular for their red to blue pigments, are of high interest in elderberry.

Most studies have found that cyanidin -based anthocyanins are the dominant type in European and American elderberry, including cyn 3-O-sambubioside -β-Dglucopyranoside and cyn 3-O-glucoside. 1,8 Cyn 3-sambubioside-5-glucoside and cyn 3,5- diglucoside are also commonly seen in the elderberry. The American elderberry has a more unique anthocyanin profile with high presence of acylated anthocyanins compared to the European elderberry, including cyn 3-O-coumaroyl-sambubioside-5-O-glucoside , cyn 3-Ocoumoaryl-sambubioside. These acylated anthocyanins may be more stable during processing, but the authors found that cyn 3-O-coumaroyl-sambubioside was the least stable anthocyanin during storage , whereas cyn 3-O-cou-sam-5- O-glu and cyn-3-O-sam-5-O-glu were more stable. Another major type of phenolic compound in elderberry is flavonol glycosides, which include rutin , isorhamnetin 3-O-glucoside or 3-O-rutinoside, and kaempferol 3-O-rutinoside. Rutin has frequently seen to be the most concentrated flavonol in European elderberry, and often the most concentrated phenolic compound of any present. S. nigra ssp. canadensis also contains higher levels of rutin than other flavonols. Other flavonol glycosides present in elderberry include kaempferol and isorhamnetin derivates, such as kaempferol-rutinoside, isorhamnetin-rutinoside, and isorhamnetin-glucoside. Phenolic acids are also present in high amounts in elderberry, including chlorogenic acid isomers , p-coumaric acid, sinnapic acid, cinnamic acid, and ferulic acid. Flavan-3-ols found in elderberry include -catechin, -epicatechin, and procyanidins. Parts of the elderberry plant are known for having toxic compounds called cyanogenic glycosides that, if consumed, can be dangerous due to the release of cyanide. The stems and leaves have the highest concentration of CNGs, followed by unripe berries and flowers, followed by ripe berries and cooked juices. The primary CNG in elderberry is sambunigrin, stacking flower pot tower which is a diastereoisomer of the more commonly known CNG prunisin. Amygdalin is the next most common CNG, though it is not often measured. Dhurrin and linamarin have also been measured in elderberry plant material. European elderberry levels of CNGs can vary greatly depending on the growing location, such that concentrations ranged from 0.08 concentrations ranged from 0.08 ± 0.01 to 0.77 ± 0.08 µg g-1 when fruit was evaluated from various altitudes in Slovenia. 6 These concentrations are lowerthan those detected in elderberry juice, found to be 18.8 ± 4.3 mg kg-1 in raw juice and 10.6 ± 0.7 mg kg-1 in cooked elderberry juice, suggesting that thermal processing can reduce CNG levels in elderberry products. American elderberries have been evaluated for their concentrations of CNGs. These include amygdalin, sambunigrin , linamarin, and dhurrin. Specifically, the Ozone and Ozark genotypes were evaluated, giving better insight into how CNG concentrations may be impacted by plant genetics. While the total concentrations of the four CNGs in the two American elderberry genotypes were somewhat similar , the composition of which CNGs made up that total were quite different: Ozone elderberries had similar levels of amygdalin and sambunigrin while Ozark elderberries had much higher levels of amygdalin than sambunigrin .The flavor profile of elderberries is an important factor in the consumer sensory experience with elderberry products. Two of the most common compounds identified as drivers of elderberry aroma identified in multiple studies of the berries or elderberry juice are β-damascenone and dihydroedulan.

Nonanol was also identified as a key volatile compound contributing to the characteristic elderberry aroma, while ethyl-9-decenoate was found to be important for the characteristic elderberry aroma by another study. While these volatile compounds can be key to the unique aroma, they are not typically the most concentrated compounds. Studies have found the most concentrated compounds to be linalyl acetate, linalool, phenylacetaldehyde, benzaldehyde , hexanal, 2- and 3-methyl-1-butanol, nonanal and benzaldehyde. However, comparing concentration of compounds across studies can be difficult due to differences in sample preparation, extraction method, and method parameters, to name a few important factors. Neither American nor blue elderberry has been evaluated for their volatile aroma composition, which limits the understanding of how these subspecies may perform and be accepted by consumers in the same formats as European elderberry. Analytical assessments of the elderberries and products using the elderberries, in addition to sensory panels would be useful information for product developers and should be performed when cultivars or genotypes are being selected for cultivation and use in commercial products.Elder flowers are frequently used in beverages and food products, including but not limited to teas, syrups, lemonades, liqueurs, wines, jams/marmalades, and tonic water. They are also used for flavoring in yogurt, coated almonds, lozenges, and confectionary goods, to name a few. Furthermore, elderflower can now commonly be found in soaps, lotions, and candles, thus consumers, especially in the United States are becoming more familiar with elderflowers, which have been well-known in Europe for generations. Topical applications are also being explored for their benefits to skin. These recent studies support the long history of use of elderflower by the Lumbee tribe in North Carolina, who use elderflower as a treatment for skin cancer by soaking flowers in witch hazel for a week then applying that to the skin. The main compound in elderflowers, like elderberries, is water, and is found in similar concentrations .Glucose, fructose, and sucrose make up the main sugars found in elderflower. While European elderflowers have a roughly equal amount of these sugars, elderflowers of the blue elderberry have a much higher level of fructose than glucose or sucrose. However, there has only been one study to measure these compounds in elderflowers, and more studies are needed to know if this trend occurs across each of the subspecies. There is limited data on these compounds across the three subspecies of interest, such as no information on the American elderberry; thus, few comparisons can be made. Minerals and vitamins have been evaluated in European elderflowers. Minerals include calcium, magnesium, copper, zinc, and manganese. Calcium is the most concentrated mineral with an average of 2955.9 ± 272.7 µg g-1 across several wild and cultivated samples and magnesium is the next most concentrate mineral at an average of 1200.2 ± 453.6 µg g-1 . Vitamin C has only been measured in elderflower syrup, ranging from 22.47 ± 0.06 mg L-1 to 46.17 mg L-1 . Elderflowers of the European subspecies have been evaluated several times for their phenolic profile. Dominant compounds in the flavonol rutin and neochlorogenic acid. Concentrations can vary greatly, just like many of the other compounds already explored in this review. Significant differences in phenolic concentrations have been found between cultivars, such that the concentration of rutin ranged from 11.6 to 42.3 mg g-1 dry weight and neochlorogenic acid ranged from 10.1 to 20.7 mg g-1 dry weight among the 16 genotypes. The coefficient of variation was greater than 10% for all of the compounds measured, including nine phenolic acids and six flavonol glycosides. American elderflowers have also been studied for their concentration of rutin and chlorogenic acid which generally align with the European elderflower profile, except that the primary phenolic acid was chlorogenic acid instead of neochlorogenic acid.