Beverage Profiling with HPLC and UHPLC

High-performance liquid chromatography (HPLC) is used to separate, identify, and quantify compounds present in various types of samples, including many beverages. Advances in instrumentation and column technology led to the development of ultra-high performance liquid chromatography (UHPLC), which offers increased resolution, speed, and sensitivity. These powerful analytical techniques are widely used in the beverage industry to detect several key compounds that provide insight into product quality, safety, and authenticity.

Beer

Phenolic compounds act as anti-oxidants, pro-oxidants, flavor precursors, flavoring agents, and interact with other beer constituents to influence key beer quality parameters: mouthfeel, beer haze, foam retention, antioxidant properties, and stability. Iso-α-acids are derived from thermal isomeration of α-acids during the brewing process. They account for much of the bitterness of beer, as well as foam stability and antibacterial properties.

Fruit Juice

Organic acids include malic, ascorbic, and citric acid. They are naturally occurring, with malic acid found predominantly in apple, pear, and stone fruits, and citric acid occurring in citrus and tropical fruits. Organic acids may also be added to juice to enhance the flavor and prevent color changes due to oxidation, however, excess synthetic organic acids can damage tooth enamel. Anthocyanins are flavonoids found in large concentrations in pomegranate juice. They have numerous bioactive effects, and unlike other flavonoids they can be absorbed and circulate in plasma without undergoing metabolic changes. With increasing demand, analysis is essential to ensure pomegranate juice quality and purity.

Wine

Catechins are a group of flavanols with anticancer, antiallergy, and antioxidant activity. High concentrations of catechins are found in grape seeds, and they are the primary components of tannin. They contribute to the bitterness of wine, a key characteristic of wine quality. Catechins are structurally similar to many other polyphenols, and necessitate techniques with high selectivity and resolution for identification and quantification. Wine authentication is an analytical process to ensure that a wine is in compliance with legal regulations. Phenolic compounds may be used to distinguish between varieties. Fungicides and insecticides are often used in vineyards to protect grapes from mold and insects, and must not exceed the established maximum residue levels permitted for wine.

Milk

Milk contains fat-soluble vitamins A, E, and D3, that are required in sufficient quantities to support human health. Accurate labeling is important, as many people rely on milk and dairy products as a source of these vitamins. Dicyandiamide is a nitrogen-rich compound that may either be added to milk as an adulterant, or contaminate milk from its use in pastures where cows graze. It is important to determine the presence of dicyandiamide in milk because its high nitrogen content can cause milk’s protein content to appear higher than it is.

Water

Phthalates such as di-ethylhexyphthalate (DHEP) are endocrine disruptors, that are potentially harmful to human health. As such, there are numerous regulations outlining maximum allowable levels for DHEP in bottled water, and manufacturers must monitor their products for DHEP once per year at minimum under good manufacturing practice regulations.

Sports Drinks

In addition to water, sports drinks contain sugar and salt to replace the carbohydrates and electrolytes lost during strenuous exercise. Advances in HPLC column technology enable carbohydrate, anion, and cation determination for quality control.

Cola

Steviol glycosides (Stevioside and rebaudioside A) are non-caloric sweeteners often used as sugar substitutes in colas. They are obtained from the Stevia rebaudiana plant and their maximal permissible limits have been defined by regulatory agencies. Caffeine is often added to cola, and can have negative side effects in high doses.

Coffee

Chlorogenic acids are phenolic antioxidant compounds found in coffee. In addition to their health benefits, these compounds convey bitterness to coffee, and increased roasting temperatures are associated with a decrease in extractable chlorogenic acid concentration.