Food Engineering / Gıda Mühendisliği

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

Browse

Filters

2013 - 20142

Settings

Author: search.filters.author.Molva, ÇelenkSubject: search.filters.subject.Inactivation

Search Results

Now showing 1 - 2 of 2
  • Article
    Citation - WoS: 14
    Citation - Scopus: 16
    Effect of Sporulation Medium on Wet-Heat Resistance and Structure of Alicyclobacillus Acidoterrestris Dsm 3922-Type Strain Spores and Modeling of the Inactivation Kinetics in Apple Juice
    (Elsevier Ltd., 2014) Molva, Çelenk; Baysal, Ayşe Handan
    Alicyclobacillus acidoterrestris is a spoilage bacterium in fruit juices leading to high economic losses. The present study evaluated the effect of sporulation medium on the thermal inactivation kinetics of A. acidoterrestris DSM 3922 spores in apple juice (pH3.82±0.01; 11.3±0.1 °Brix). Bacillus acidocaldarius agar (BAA), Bacillus acidoterrestris agar (BATA), malt extract agar (MEA), potato dextrose agar (PDA) and B. acidoterrestris broth (BATB) were used for sporulation. Inactivation kinetic parameters at 85, 87.5 and 90°C were obtained using the log-linear model. The decimal reduction times at 85°C (D85°C) were 41.7, 57.6, 76.8, 76.8 and 67.2min; D87.5°C-values were 22.4, 26.7, 32.9, 31.5, and 32.9min; and D90°C-values were 11.6, 9.9, 14.7, 11.9 and 14.1min for spores produced on PDA, MEA, BATA, BAA and BATB, respectively. The estimated z-values were 9.05, 6.60, 6.96, 6.15, and 7.46, respectively. The present study suggests that the sporulation medium affects the wet-heat resistance of A. acidoterrestris DSM 3922 spores. Also, the dipicolinic acid content (DPA) was found highest in heat resistant spores formed on mineral containing media. After wet-heat treatment, loss of internal volume due to the release of DPA from spore core was observed by scanning electron microscopy. Since, there is no standardized media for the sporulation of A. acidoterrestris, the results obtained from this study might be useful to determine and compare the thermal resistance characteristics of A. acidoterrestris spores in fruit juices. © 2014 Elsevier B.V.
  • 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.