Prevention of turbidity in pomegranate juice concentrate during storage time

Sert, Dilara
This study aimed at finding a solution to turbidity problem in pomegranate juice concentrate during storage without reprocessing. In this study Hicaz type pomegranates (Punica Granatum L. ) (Hicaznar) were processed into clear fruit juice. Based on the literature studies and the interviews with the sector representatives (Novozymes and Erbslöh), the experiments were carried out on the effect of gelatin in preventing turbidity. In addition, the effect of filtration process of oxalic acid crystals, which is one of the turbidity factors, were also determined. For this purpose, four different trial plans were developed considering all possibilities. In the first experimental design, fresh fruits firstly are sorted, washed and removed from shells. Then crushing, pressing, pasteurization, enzymation, clarification, filtration and concentration stages have been followed. In the second experimental design, after ultrafiltration process pomegranate juice is brought to 30-35 brix, stored at cold temperatures (at three different temperatures) and then passed through paper filter. In the third experimental design, in the clarification stage gelatin is added and followed as in first plan. In the last experimental design, gelatin, cold storage and filter stages are applied. Experimental design 1 and 2; experimental design 3 and 4 is conducted at the same time interval. In this study; sorting, washing and milling steps were conducted in production factories DÖHLER A.Ş. and production of pomegranate juice vi concentrate were simulated with the studies that started in the pilot plant and continued in the laboratory and the solution to turbidity was sought. It was determined that stability problems were not observed in plans using gelatin. In cases where gelatin is not used, it is shown that the waiting period in production should be selected at least 24 hours for three different temperature values to provide stability of products.
Citation Formats
D. Sert, “Prevention of turbidity in pomegranate juice concentrate during storage time,” Thesis (M.S.) -- Graduate School of Natural and Applied Sciences. Food Engineering., Middle East Technical University, 2019.