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Fructooligosaccharides have important potential use in the food industry due to their properties such as solubility in water, stability in acidity of fruit juices and during storage, low-calorie value and prebiotic effects. In this study, for the first time, Zymomonas mobilis levansucrase was used for in situ 6-kestose production in carob molasses. The produced kestose was stable during storage at 20 degrees C for 4 months. The product was evaluated for color, non-enzymatic browning index and titratable acidity during storage and the quality of the product was found comparable to that of control. Furthermore, the decreased amount of sucrose resulted in the prevention of 5-hydroxymethylfurfural (5-HMF) formation during storage. As a result, carob molasses was converted into a high-quality prebiotic product with decreased sucrose content and reduced 5-HMF quantities, and a new method was developed to prevent 5-HMF formation in fruit juices and molasses.

Levan gıda, kozmetik ve ilaç sanayi gibi birbirinden farklı endüstrilerde kullanım alanına sahip bir fruktoz polimeridir. Levansukrazlar sakkarozu substrat olarak kullanarak fruktoz polimerleri oluşumunu katalizleyen enzimlerdir. Bakteriler tarafından hücre dışına salgılanan levansukrazlar bakterinin yüksek sakkaroz konsantrasyonunda levan ve/veya fruktooligosakkarit polimerlerini sentezlemesini sağlar. Bu çalışmada Zymomonas mobilis NRRL B-14023 kullanılarak levansukraz enziminin üretilmesi ve levan polimeri üretme koşulları incelenmiştir. Yapılan çalışmada Z. mobilis levansukrazı üretilmiş ve ham enzimin levan aktivitesi gösterilmiştir. Levansukraz, Z. mobilis B-14023 hücreleri tarafından 36 saat boyunca 30.3 °C’de 159 g/L sakkaroz, pH 4.91 ortamında statik kültürde üretilmiştir. Levansukrazın levan üretimi için optimum inkübasyon süresi ve sıcaklığı 24 saat ve 25 °C olarak bulunduktan sonra aktiviteye etki eden faktörler araştırılmıştır. Artan NaCl konsantrasyonunda levan üretiminde azalma olduğu görülmüştür. Ayrıca 10 mM EDTA ve MgCl2 varlığında enzimin levan üretim aktivitesinde azalma olduğu bulunmuştur. Sonuç olarak Z. mobilis NRRL B-14023 levansukrazı ile ortalama 62.42 g/L levan üretilmiştir., Levan has a wide range of uses in different industries such as food, cosmetics and pharmaceutical. Levansucrases are enzymes, which catalyze the formation of fructose polymers using sucrose as substrate. Levansucrases are produced and secreted by bacteria and enable them to synthesize levan/fructooligosaccharides in medium containing high sucrose concentrations. In this study, Zymomonas mobilis levansucrase was produced and its levan activity was investigated. Levansucrase was produced by Z. mobilis NRRL B-14023 cells in static culture in medium with 159 g/L sucrose, pH 4.91 at 30.3 °C for 36 h. The optimum incubation time, temperature of crude enzyme for levan production were found as 24 h and 25 °C. The levan production of levansucrase decreased with increasing NaCl concentrations. Furthermore the presence of 10 mM EDTA and MgCl 2 showed an inhibitory effect on levan production. As a result, on average 62.42 g/L levan was produced using Z. mobilis NRRL B-1423 levansucrase.