Response surface methodology for extraction of chia seed phenolics and their quantification by LC-MS/MS

Salvia hispanica L. species, also known as "Chia," is an annual plant belonging to the Lamiaceae family. Chia seeds are of great importance in the daily diet due to their high quality components, such as proteins, carbohydrates, fibers, minerals, antioxidants and fats. In the present study, optimum maceration conditions were determined for preparation of chia seed extracts with high total phenolic compound content by experimental design approach. For this purpose, a response surface methodology type known as Box-Behnken design was applied. Ethanol concentration of the extraction solvent, extraction time and solvent volume were examined as the independent variables, whereas the total phenolic content was the response. The developed experimental model was evaluated statistically and found to fit well, considering the lack of fit p-value of 0.184 and coefficient of determination as 0.9731 at the 95% confidence level. The extract prepared by optimized conditions as 56.1 minutes of extraction time and 49.5 mL of solvent volume containing 61.4% ethanol had a total phenolic content of 53.5 ± 1.9 μg of pyrocatechol equivalent/mg extract. The phenolic compounds of the prepared extract were quantified by liquid chromatography-tandem mass spectrometry. Rosmarinic acid was found to be the major component with a concentration of 22.702 mg/g extract.