Titratable Activity of Acid Tastants

Abstract

When measuring acidity in foods and beverages there are two common units of measurement: titratable acidity and pH. There is no direct relationship between pH and titratable acidity, therefore, both must be measured experimentally. Titratable acidity (TA), also referred to as total acidity, measures the total acid content in a food or beverage system and is determined by titration of the acids in the food system with a standard base. BASIC PROTOCOL POTENTIOMETRIC AND COLORIMETRIC ACIDITY TITRATIONS The choice of titration protocol to determine the TA of a sample is dependent primarily on the color of the sample. The colorimetric titration uses phenolphthalein indicator solution to determine the endpoint of the titration. Phenolphthalein indicator solution turns from colorless to pink upon reaching the endpoint; therefore, if the color of the sample interferes with this color change, the potentiometric titration is the best method. However, when using colorimetric titration, it is also common to titrate to an endpoint of pH 8.2, the endpoint of the phenolphthalein solution. Materials Sample Deionized, distilled water (ddH 2 O) 0.1 N sodium hydroxide solution, normalized (see recipe) 1% phenolphthalein indicator solution pH meter (Corning, Orion) pH electrode 250-ml beakers (potentiometric titration) 250-ml Erlenmeyer flasks (colorimetric titration) Small magnetic stir bars Blender (optional; if the sample needs to be macerated) Magnetic stir plate 50-ml buret Buret clamp Clamp support Stopcock Small glass funnel Contributed by Jane E. Friedrich

Profiling ellagic acid content: The importance of form and ascorbic acid levels

“…The pH and titratable acidity (TA) of the fruit purees were measured according to the method outlined by Fredrich (2005). After defrosting the frozen sample in a microwave (as recommended by Oszmianski et al, 2009 to reduce drip loss and the possibility of chemical deterioration) the fruit was macerated in a Black & Decker BMC 100 blender (Black & Decker, Mooroolbark, Vic, Australia) at 100 rpm for 2 min.…”

“…-milliequivalent weight of the standard; and v -sample volume (ml). Citric acid was selected as the standard acid for these calculations after consulting Table G2.1.1 in Fredrich (2005).…”

The comparative effect of steaming and irradiation on the physicochemical and microbiological properties of dried red pepper (Capsicum annum L.)

“…41). The pH of the extract was obtained using a pH metre (Thermo Scientific Orion Star Series, USA) based from the method of Friedrich (2000). The extractable yield content was determined by placing a 2 ml sample extract in an aluminium disk having a pre-determined constant weight and dried in an oven at 105°C until a constant weight was obtained (Waje et al, 2008).…”

Influence of the Colloidal Structure of Dairy Gels on Milk Fat Fusion Behavior: Quantification of the Liquid Fat Content by In Situ Quantitative Proton Nuclear Magnetic Resonance Spectroscopy (isq 1H NMR)

“…Rhamnosus ) was added (CGD‐Yalacta, Caen, France) as a lactic bacterial starter (Majamaa and others ). Samples were heated at 45 °C for 3.0 h (CGD‐Yalacta recommendations), until the pH, measured by pH‐meter (CyberScan pH 1100 with ATC probe, EutechIntruments, Nijkerk, The Netherlands) following the method of pH analysis of food samples (Friedrich ), reached 4.40 ± 0.05, this value being considered as indicating the end of the fermentation process (Pernoud and others ). DG were stored at 4 °C in closed glass beakers before the analyses in order to curb bacterial development and to minimize structure modifications (Pernoud and others ).…”