The researchers determined the caffeine content in Indian Arabica and Robusta green coffee. They found that Robusta coffee had a higher caffeine content than Arabica coffee. They used chloroform isolation and UV-VIS spectrophotometric methods to analyze the caffeine levels. The results showed 182 mg of caffeine per 100 g in Robusta coffee and 154 mg per 100 g in Arabica coffee. The spectrophotometric analysis confirmed the presence of caffeine in both types of coffee.