Application of titrator in quality inspection of condiments

​​​1. Introduction to condiments

Condiments refer to supplementary foods that can increase the color, aroma, and taste of dishes, promote appetite, and are beneficial to human health. Condiments can be divided into salty condiments, sweet condiments, bitter condiments, spicy condiments, sour condiments, etc. according to their taste. In addition to the single-flavored condiments, there are also compound-flavored condiments, such as oil curry, sweet noodle sauce, milk curd sauce, pepper and salt.

Table salt is the source of condiments, and all condiments, including compound flavors, are inseparable from table salt. The main ingredient of table salt is sodium chloride. Excessive intake of salt in the diet can cause high blood pressure. The World Health Organization (WHO) recommends that each person consume less than 6g of salt per day to prevent coronary heart disease and high blood pressure. Our country stipulates that adults can consume 6g of salt per day to meet the body's need for sodium.

2. Determination method of sodium chloride in condiments

At present, the methods for determining chloride in food in national food safety standards include potentiometric titration, Volhard method (indirect precipitation titration method), and silver measurement method (molar method or direct titration method). Volhard method (indirect precipitation titration method) and silver measurement method (molar method or direct titration method) both use color to determine the end point. The condiments with complex flavors (sweet chili sauce, tomato sauce, oil curry) have their own color, It interferes with the judgment of the end point, so we use the potentiometric titration method to determine the chloride ion content in the compound flavor seasoning.

3. Use a Potentiometric Titrator to determine sodium chloride in condiments

(1) Instrument: REX ZDJ-5B Automatic Potentiometric Titrator

(2) Electrodes: silver titration Electrode (U-shaped fork piece interface, customized) and 231-01 pH glass electrode.

(3) Reagents: ultrapure water, nitric acid, acetone, silver nitrate standard titrant, etc.

(4) Samples: sweet chili sauce, tomato sauce, oil curry

(5) The measurement process is as follows:

Standard Measurment---Blank Titration----Sample pretreatment---Sample Measurment.