This Is AuburnElectronic Theses and Dissertations

Caffeine Content of National and Store Brand Carbonated Beverages




Chou, Ken-Hong

Type of Degree



Nutrition and Food Science


Caffeine is a well-known stimulant which is added as an ingredient to various carbonated soft drinks. Caffeine has drawn more attention due to its physiological effects beyond that of its stimulatory effect. Consumers are interested in knowing the exact amounts of caffeine existing in beverages. However, limited data exist, especially for store brand beverages. Therefore, the caffeine content of 56 types of national and 75 types of store brand carbonated beverages were analyzed. The caffeine determination was accomplished by utilizing high performance liquid chromatography (HPLC) equipped with a UV/Visible detector. The mobile phase consisted of 20%:80% (v/v) acetonitrile and deionized water. The chromatographic separation occurred on two C-18 columns. Each beverage sample was diluted 3-fold with deionized water. Duplicate analyses of multiple lots were performed on all beverage samples. Some of the more popular national brand carbonated beverages analyzed for caffeine in this study were Coca-Cola (33.9 mg/12 oz), Diet Coke (46.3 mg/12 oz), Pepsi (38.9 mg/12 oz), Diet Pepsi (36.7 mg/12 oz), Dr. Pepper (42.6 mg/12 oz), Diet Dr. Pepper (44.1 mg/12 oz), Mt. Dew (54.8 mg/12 oz), and Diet Mt. Dew (55.2 mg/12 oz). The caffeine content of Vault Zero (74.0 mg/12 oz) and Ritz Cola (10.3 mg/12 oz) were the highest and lowest values in the national brand carbonated beverages. On the other hand, the caffeine content of Big Fizz Diet Cola (61.9 mg/12 oz) and IGA Cola (4.9 mg/12 oz) were the highest and lowest values determined in the store brand carbonated beverages. Most store brand carbonated beverages were found to contain less caffeine than their national brand counterparts. The national brand carbonated beverages exhibited better quality control than store brand ones. New flavors, formulas, and brands of carbonated beverages continue to be introduced into the market. The food labels on the beverages simply provide the existence of caffeine, but no information about the exact amount. The lacking caffeine information results in consumers not knowing their caffeine ingestion levels. Through the present study, food companies, research and educational institutions, dietitians, and consumers will have access to more comprehensive and updated caffeine data on national and store brand carbonated beverages.