Effect of Storage Conditions on Citric Acid Content of Beverages Available in Erbil Local Markets

Abstract

Citric acid has antimicrobial and acidulate properties that support other ingredients' antioxidant benefits and enhance the flavors of syrups, soft drinks, and juices, citric acid is used as a multi-functional food additive in the manufacturing of many foods. Poor storage leads to chemical and physical changes in food and beverages. The effect of temperature and sunlight on storage is considered one of the most important studies in the field of food. The effect of both factors on the concentration of citric acid in beverages available in local markets was studied. Here in, a spectrophotometric method for citric acid determination in beverages was proposed. The basis for the determination is citric acid’s inhibitory effect on the thiocyanate – ferrate ion complexation reaction. Citric acid forms complexes with Fe(III), therefore, a decrease in absorbance of the complexation product is monitored at 477 nm. The recommended method's numerous chemical and physical parameters were optimized, and interfering species were also investigated. The calibration graph was constructed in the linear range from 1.0 to 50 mg/L of citric acid with a relative standard deviation of 0.87%, and the results are compared to those obtained from Boehringer–Mannheim ultraviolet method test combination kit for citric acid with an error between -0.51 and 1.86%. The citric acid in commercial beverages has been successfully determined using the approach, which was shown to be sufficiently selective. The results showed that incorrect storage of beverages at 45 ℃ leads to a decrease in the concentration of citric acid from 1999 to 1778, 1930 to 1815, and 1930 to 1825 µg/mL for standard citric acid, canned beverage (7up, and Lipton ice tea), and bottled drinks (Fanta, and Sprite), respectively. Sunlight leads to decrease in citric acid concentrations from 1998 to 1848, and 1999 to 1451 µg/mL for canned beverage and bottled drinks, respectively due to the degradation of the acid.

Keywords

• Citric acid, beverages, storage effect, temperature effect, sunlight effect, spectrophotometry