SIMPLE MEASURING METHOD OF ACIDITY FOR FRUIT JUICE

摘要

PURPOSE:To simply and quickly measure the acidity in high accuracy without being affected by salts in fruit juice or gaseous CO2 in the atmosphere, by diluting the fruit juice to prescribed time as much and measuring its pH and then finding the concentration of the acidity of the fruit juice basing on this pH and preliminarily found correlative expression. CONSTITUTION:Fruit juice is diluted to 50 times as much by pure water and pH is measured by using an electrode for pH measurement. On one hand, the acidity of each solution of the fruit juice is found by a neutralizing titration method and a graph shown by the figure which is plotted said acidity and the acidity found by said pH value, is prepared and then, the acidity of the fruit juice is found by referring to these data. Otherwise, it is read directly by preparing an acidimeter graduated with a logarithmic scale of the acidity corresponding to a pH value scale on an indicator having the same construction as the pH meter. In this manner, the acidity measurement having nearly no measuring error is performed by bringing acidity near to pH 4 by diluting the original liquid of the fruit juice because the pH of nearly all of the original liquid is near 3.5.