ABSTRACT
This chapter aims to provide guidance for potential users to choose suitable analytical methodology for determining organic acids in dairy products. There are various analytical methods available, and the authors describe these methods and summarize and compare the advantages and limitations of each method. The chapter starts with a general introduction of organic acids and titration acid, enzymatic, and chemical “wet” methods that are designed for the quantification of a single organic acid. Additionally, instrument-based methods such as capillary electrophoresis (CE) and Fourier transform infrared (FTIR) spectroscopy methods that have potential future applications due to their rapidness and ease of performance are described. Finally, high-performance liquid chromatography (HPLC) and gas chromatography (GC) are described. These methods are the most widely utilized and applicable methods for the determination of organic acids in dairy products. The GC method can be used to analyze a whole spectrum of fatty acids. However, sample preparation requirements including derivatization requirements for some organic acids make the GC method most applicable for the analysis of short-chain volatile carboxylic acids. For the determination of a variety of water-soluble organic acids, HPLC-based methods are recommended. Extraction with diluted sulfuric acid and separation with an ion-exchange column with UV detection at two wavelengths is the most commonly chosen HPLC-based method.
