Food Engineering / Gıda Mühendisliği

Permanent URI for this collectionhttps://hdl.handle.net/11147/12

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  • Article
    Citation - WoS: 5
    Modeling Growth of Alicyclobacillus Acidoterrestris Dsm 3922 Type Strain Vegetative Cells in the Apple Juice With Nisin and Lysozyme
    (AIMS Press, 2017) Molva, Çelenk; Baysal, Ayşe Handan
    In the present study, the effect of storage temperature on A. acidoterrestris DSM 3922 cells (105 CFU/mL) was examined during growth in reconstituted apple juice (pH 3.8, degrees Brix 11.3) containing nisin (0-100 IU/mL) and lysozyme (0-100 mg/L). The growth curves were obtained at three temperatures of 27, 35 and 43 degrees C using absorbance data (OD600nm). Based on the results, the minimal inhibitory concentrations (MICs) of nisin were found as 10 IU/mL at all tested temperatures. On the other hand, increasing the temperature decreased the amount of lysozyme for growth inhibition. The MICs of lysozyme were found as 10, 2.5 and 1.25 mg/L at 27, 35 and 43 degrees C, respectively. At selected non-inhibitory doses, nisin (1.25-5 IU/mL) and lysozyme (0.3-2.5 mg/L) prolonged the lag time compared to the controls at the corresponding temperatures. In addition, there was a strong linear relationship between the lag time and lysozyme concentrations at 27 and 35 degrees C (R-2 > 0.98). The results of this study demonstrated that both nisin and lysozyme could be used to inhibit the growth of A. acidoterrestris cells in the apple juice. The results also indicated that the growth parameters were variable depending on the storage temperature and the type of the antimicrobial agent used in the apple juice.
  • Article
    Citation - WoS: 9
    Citation - Scopus: 12
    Effects of Pomegranate and Pomegranate-Apple Blend Juices on the Growth Characteristics of Alicyclobacillus Acidoterrestris Dsm 3922 Type Strain Vegetative Cells and Spores
    (Elsevier Ltd., 2015) Molva, Çelenk; Baysal, Ayşe Handan
    The present study examined the growth characteristics of Alicyclobacillus acidoterrestris DSM 3922 vegetative cells and spores after inoculation into apple, pomegranate and pomegranate-apple blend juices (10, 20, 40 and 80%, v/v). Also, the effect of sporulation medium was tested using mineral [Bacillus acidoterrestris agar (BATA) and Bacillus acidocaldarius agar (BAA)] and non-mineral containing media [potato dextrose agar (PDA) and malt extract agar (MEA)]. The juice samples were inoculated separately with approximately 105CFU/mL cells or spores from different sporulation media and then incubated at 37°C for 336h. The number of cells decreased significantly with increasing pomegranate juice concentration in the blend juices and storage time (p<0.001). Based on the results, 3.17, 3.53, and 3.72 log cell reductions were observed in 40%, 80% blend and pomegranate juices, respectively while the cell counts attained approximately 7.17logCFU/mL in apple juice after 336h. On the other hand, the cell growth was inhibited for a certain time, and then the numbers started to increase after 72 and 144h in 10% and 20% blend juices, respectively. After 336h, total population among spores produced on PDA, BATA, BAA and MEA indicated 1.49, 1.65, 1.67, and 1.28 log reductions in pomegranate juice; and 1.51, 1.38, 1.40 and 1.16 log reductions in 80% blend juice, respectively. The inhibitory effects of 10%, 20% and 40% blend juices varied depending on the sporulation media used. The results obtained in this study suggested that pomegranate and pomegranate-apple blend juices could inhibit the growth of A. acidoterrestris DSM 3922 vegetative cells and spores.
  • Article
    Citation - WoS: 76
    Citation - Scopus: 89
    Uv-C Light Inactivation and Modeling Kinetics of Alicyclobacillus Acidoterrestris Spores in White Grape and Apple Juices
    (Elsevier Ltd., 2013) Baysal, Ayşe Handan; Molva, Çelenk; Ünlütürk, Sevcan
    In the present study, the effect of short wave ultraviolet light (UV-C) on the inactivation of Alicyclobacillus acidoterrestris DSM 3922 spores in commercial pasteurized white grape and apple juices was investigated. The inactivation of A. acidoterrestris spores in juices was examined by evaluating the effects of UV light intensity (1.31, 0.71 and 0.38mW/cm2) and exposure time (0, 3, 5, 7, 10, 12 and 15min) at constant depth (0.15cm). The best reduction (5.5-log) was achieved in grape juice when the UV intensity was 1.31mW/cm2. The maximum inactivation was approximately 2-log CFU/mL in apple juice under the same conditions. The results showed that first-order kinetics were not suitable for the estimation of spore inactivation in grape juice treated with UV-light. Since tailing was observed in the survival curves, the log-linear plus tail and Weibull models were compared. The results showed that the log-linear plus tail model was satisfactorily fitted to estimate the reductions. As a non-thermal technology, UV-C treatment could be an alternative to thermal treatment for grape juices or combined with other preservation methods for the pasteurization of apple juice.