Determination of the characteristics of fruit juice added kefir in the storage period

ABSTRACTM.Sc. ThesisDETERMINATION OF THE CHARACTERISTICS OF FRUITJUICE ADDED KEFIR IN THE STORAGE PERIODÖmer GÜNGÖRAfyon Kocatepe UniversityGraduate School of Natural and Applied SciencesDepartment of Food EngineeringSupervisor: Assist. Prof. Dr. Abdullah ÇAĞLARThis study was carried out to determine the effect of different kefir applications (pure,glucose added, orange added, grapefruit added) and storage periods (the first day, 7thday and 21th day) on lactose rate, protein content, ash content, vitamin C content, pH,SH, oil rate, the rate of oil free dry matter, the rate of total dry matter. Besides, sensualanalyses were made for color, odor and taste.While decrease occurred in lactose rate, vitamin C content, and pH with increasingstorage period; protein content, SH, the rate of oil free dry matter and the rate of totaldry matter increased with increasing storage period. The highest values in lactose rate,protein content, ash content, pH, oil rate were obtained from pure kefir. Orange addedkefir gave the highest vitamin C content, and the highest rate of oil free dry matter andthe rate of total dry matter were found in glucose added kefir. Sensual analyses showedthat increasing storage period increased deterioration in color, odor and taste, andorange and grapefruit added kefir seemed the most preferred ones for color, odor andtaste. Depending on increasing storage period, negativeness in characteristics andpreference of kefir increases. Orange and grapefruit addition to kefir increasescharacteristics and preference of kefir. To increase consumption of kefir in the society,it is essential that fresh kefir should be consumed as far as possible, kefir having highnutrition like orange/grapefruit added kefir should be put on sale.2007, 59 pagesKey Words: Orange added kefir, grapefruit added kefir, storage period, vitamin C.iv