A New Method to Detect Sodium Benzoate in Grapefruit Juice Based on Capacitance Measurement: Preliminary Study

Sodium Benzoate (E2ll) is widely used in food today and has extremely harmful effects on human health such as causing cancer, damaging the liver, or increasing symptoms of hyperactivity. This chemical is widely marketed, and used at higher levels than experts recommend of 647–825 mg/kg body weight per day. Therefore, the research focuses on finding a new, fast, and cost-effective method to detect sodium benzoate in fruits, especially grapefruit. The designed system is a capacitance measurement one. The grapefruit juice is considered the solvent of the capacitor. The difference in solvent leads to the change in a measured capacitor. So, in this research, two different samples include one is fresh grapefruit juice and another is E211 mixed with grapefruit juice used to measure the capacitance by using the system. Results of 15 different samples of grapefruit juice including 15 samples having chemicals (E211) and 15 others without chemical shows that the capacitance of normal grapefruit juice is about l40nF, and the capacitance of grapefruit juice mixed with chemical is about l30nF. However, the decrease of the capacitance of normal grapefruit juice (140nF down to 100nF) is faster than the one having chemicals (130nF down to l20nF) after 8 hours. The different capacitance in the two cases shows that capacitance measurement is suitable to detect the existence of E2ll in grapefruit juice, not only in capacitance measurement but also in the changing of capacitance during the time. In the future, complex capacitance measurement methods will be applied to find out more significant parameters to detect the existence of Sodium Benzoate in juice, not only in grapefruit juice but also in other types of juice to protect people's health.