HPLC ANALYSIS OF ORGANIC ACIDS IN RECOMBINED IRANIAN FERMENTED WHITE CHEESE

Recombined milk products such as cheese are of importance in countries with low raw milk production or with difficulty of milk collection. Therefore, composition and physicochemical properties of such products would be of considerable value. In this study four types of Iranian recombined fermented white cheese were processed with skim milk powder plus butter oil with or without stabilizer, and ripened for two months at 13 ±1°C in 10% salt solution. Organic acids of the cheese were determined by an HPLC equipped with SCR-IOI H column and U.V. monitor at 210 nm using standards with more than 99.5% purity and percent recovery. Organic acids such as oxalic, orotic, citric, oxalacetic, succinic, lactic, formic, acetic, D-pyroglutamic, propionic, butyric, and hippuric were quantitatively determined in all samples. Results revealed different amounts compared with the results obtained for four types of natural cheeses processed in the pilot plant or prepared from the market. More acids were quantified in natural cheese samples than in recombined cheese. Formic acid was significantly higher in recombined than natural cheese. Hippuric acid was present only in one type of recombined cheese. Several other acids such as isocitric, cisaconitic and alpha-ketoglutaric were only detected qualitatively in cheeses.