Akademik Veri Yönetim Sistemi
Tezin Türü: Doktora
Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, Gıda Mühendisliği Bölümü, Türkiye
Tezin Onay Tarihi: 2017
Öğrenci: SUZAN TİREKİ
Eş Danışman: SERPİL ŞAHİN, SERVET GÜLÜM ŞÜMNÜ
Özet:The main aim of this study was to correlate sensorial changes with instrumental techniques to predict shelf life during storage of jelly gums. Effects of glucose syrup:sucrose ratio, starch and gelatine content on quality and sensorial properties of jellies were investigated. Glucose syrup: sucrose ratio, starch and gelatine contents affected hardness significantly. Moisture content, water activity, total soluble solids, pH, springiness and gumminess was influenced by only glucose syrup:sucrose ratio. Moisture content changes after a week at 30°C were similar to those after 8 weeks at 15-22°C. At 30°C, the rate of change in water activity was more than double as compared to 10°C and 20°C. Formulations with glucose syrup:sucrose ratio of 1.5 were more stable in terms of pH and colour. Glass transition temperatures increased after storage. Formulation with glucose syrup:sucrose ratio of 1.5, no starch and 6% gelatine was the most stable formulation in terms of hardness and gumminess. Moisture diffusion coefficients were determined to be between 5.93×10-10m2/s and 5.46×10-10m2/s. In sensory analysis, starch content was more effective on appearance and gelatine was more effective on texture of jellies. Storage of about 8 weeks at 30°C was equivalent to storage of 52 weeks at 15-22°C when sensory taste liking was correlated with sugar profile. Therefore, 30°C could be selected for accelerated shelf life testing. Jellies with no starch, 6% gelatine and glucose syrup:sucrose ratio of 1.5 had the most stable formulation in terms of critical parameters with high sensory scores and shelf life was determined as 52 weeks.