Organic Acid Composition and Quality of Japanese “Shibazuke” Pickles

For two types of “Shibazuke” samples matured at Ohara in Kyoto, the organic acid composition using HPLC analysis, Hunter's diagrams and sensory evaluation were investigated. One type has a good color tone (vivid magenta color) and is called a normal product (G-S). The other type has poor color and is called abnormal (P-S). The main organic acid component of both samples was lactic acid, and followed by acetic acid. Butyric acid, propionic acid and valeric acid were detected, especially in P-S. The pH of 4.2 in P-S is higher compared with the pH of 3.4 in G-S. Both samples are located on the purple color side in Hunter's diagrams. The difference in macroscopic evaluation between G-S and P-S was recognized as “perceivable” by the total color-difference of ΔE values of 17.2 N.B.S. P-S showed a significantly lower value in a sensory evaluation of flavor, but it did not smell putrid. The sensory evaluation value of sourness showed no significant difference, while that of color and total evaluation value were significantly higher in G-S.