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.


Preparation and Characterization of a Novel Solid-Phase Microextraction Material for Application to the Determination of Pesticides
Dizdas, Tugberk Nail; Pelit, Fusun Okcu; KORBA, KORCAN; PELİT, LEVENT; Kanik, Fulya Ekiz; Toppare, Levent Kamil; ERTAŞ, HASAN; ERTAŞ, FATMA NİL (2016-05-02)
The preparation and characterization of a novel solid-phase microextraction fiber is reported with application to the determination of pesticides in fruit juice. The fiber was fabricated by electrochemically coating a stainless steel wire with a thin polymeric film of 4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl) benzenamine. The procedure was initiated in 10mL of acetonitrile containing 5.5mg of monomer, 0.1mol NaClO4, and 0.1mol LiClO4 by cycling the potential between -0.5 and 1.2V with a scan rate of 100mV/se...
Survey of sulfites in wine and various Turkish food and food products intended for export, 2007-2010
Ulca, P.; Ozturk, Y.; Senyuva, H. Z. (2011-01-01)
Surveys were carried out between 2007 and 2010 to determine the total levels of sulfites in 1245 samples of wines, dried apricots, dried vegetables, nuts, juices and purees, frozen foods and cereals containing dried fruit supplied by food inspectors and by food producers for testing or for export certification. Sulfite analysis of wine was carried out using the Ripper method with an LOQ of 5 mg l(-1) and for dried and other foods the Monier-Williams distillation procedure was employed with an LOQ of 10 mg k...
Effect of L cysteine kojic acid and 4 hexylresorcinol combination on inhibition of enzymatic browning in Amasya apple juice
İYİDOĞAN, Nükhet; Bayındırlı, Alev (2004-05-01)
In this study, the effect of different anti-browning agents on the enzymatic browning in the cloudy apple juice from Amasya cultivar was compared by considering colour changes. For this purpose, L-cysteine, kojic acid and 4-hexylresorcinol were used at different concentrations in the apple juice (0-4 mM). They were found as effective inhibitors. The combination of L-cysteine, kojic acid and 4-hexylresorcinol was also studied for the control of enzymatic browning. The results showed that 89.2% inhibition was...
Effect of high pressure homogenization (microfluidization) on the quality of Ottoman Strawberry (F-Ananassa) juice
KARAÇAM, Cagri Helin; Şahin, Serpil; Öztop, Halil Mecit (2015-12-01)
In this study, effect of high pressure homogenization (HPH) on the physical and chemical properties of Ottoman Strawberry juice was investigated. The juice was processed at two different pressures (60 MPa and 100 MPa) with two different passes (2 and 5 passes). Antioxidant activity, total phenolic content (TPC), mean particle size, color, viscosity and total soluble solid content of the samples homogenized with different passes and pressures were evaluated. Mean particle size and CIE L*a*b* color values of ...
Inhibition of enzymatic browning in cloudy apple juice with selected antibrowning agents
Bayındırlı, Alev (2002-06-01)
Golden Delicious apple juice was subjected to enzymic browning in the presence of the selected antibrowning agents: ascorbic acid, isoascorbic acid, l-cysteine, sorbic acid, benzoic acid, cinnamic acid and β-cyclodextrin. The relative effectiveness of these antibrowning agents for inhibition of enzymic browning in apple juice was determined in terms of colour and enzyme activity measurements with respect to time for approximately one day storage period at . The most effective agents were determined as l-cys...
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.