Browsing by Author "Atmaca, Bahar"

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Citation - WoS: 5
Citation - Scopus: 6
Corn Processing by Pulsed Electric Fields With Respect To Microbial Inactivation and Improvement of Seed Vigour
(Elsevier Sci Ltd, 2024) Evrendilek, Gulsun Akdemir; Uzuner, Sibel; Atmaca, Bahar; Uzuner, Sibel; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Pulsed electric field (PEF) treatment of corn grains to improve seed vigour and inactivation of endogenous microflora by energies ranging from 1.20 to 28.8 J were applied to determine effectiveness of applied energies on germination rate (GR), normal seedling rate (NSR), electrical conductivity (EC), ability to germinate under salt (100- and 200 mM salt) and cold (at 10 degrees C for 7 days and at 25 degrees C for 5 days) stresses. Moreover, the effect of PEF treatments was further investigated for the inactivation of total aerobic mesophilic bacteria (TAMB), total mold and yeast (TMY), and inactivation rate (%) of Aspergillus parasiticus. Increased energy provided 11.10 % increase in GR, 21.22 % increase in NSR, 95.50 % increase in germination at 10 degrees C for 7 days. Germination under stress conditions revealed 32.53 %, 68.35 %, and 76 % increase in germination at 25 degrees C for 5 days, under 100 mM- and 200 mM NaCI salt stresses. Inactivation on the mean initial TAMB and TMY were approximately 9.25 and 7.93 log, respectively, with 63.33 +/- 0.22 % reduction in A. parasiticus culture. PEF treated corn seedlings had stronger and taller body formation with stronger roots. The most optimal processing parameters were detected as 300 Hz, 28.80 J, and 19.78 sec. PEF treatment carries a high potential to improve corn vigour with inactivation of surface microflora.
Citation - WoS: 2
Citation - Scopus: 3
High-Pressure Processing of Traditional Hardaliye Drink: Effect on Quality and Shelf-Life Extension
(MDPI, 2023) Atmaca, Bahar; Uzuner, Sibel; Demiray, Merve; Akdemir Evrendilek, Gülsün; Bulut, Nurullah; Uzuner, Sibel; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Hardaliye, as one of the oldest and lesser known traditional beverages, is produced using red grape pomace from wine production. This drink production is achieved through lactic acid fermentation, with the addition of sour cherry leaves and mustard seeds-either heat-treated, grinded, or whole-in various concentrations. Hardaliye has a very short shelf life; thus, efforts have recently been made to process hardaliye with novel processing technologies in order to achieve shelf-life extension. Therefore, the high-hydrostatic-pressure (HHP) processing of hardaliye was performed to determine its impact on important properties, including in microbial inactivation and shelf-life extension, with respect to a Box-Behnken experimental design. Maximum log reductions of 5.38 & PLUSMN; 0.6, 5.10 & PLUSMN; 0.0, 5.05 & PLUSMN; 0.2, and 4.21 & PLUSMN; 0.0 with HHP were obtained for Brettanomyces bruxellensis, total mesophilic aerobic bacteria, Lactobacillus brevis, and total mold and yeast, respectively. The processing parameters of 490 MPa and 29 & DEG;C for 15 min were found as the optimal conditions, with the response variables of an optical density at 520 nm and the inactivation of L. brevis. The samples processed at the optimal conditions were stored at both 4 and 22 & DEG;C for 228 d. While the non-treated control samples at 4 and 22 & DEG;C were spoiled at 15 and 3 d, the HHP-treated samples were spoiled after 228 and 108 d at 4 and 22 & DEG;C, respectively.
Citation - WoS: 13
Citation - Scopus: 15
Prediction of Aspergillus Parasiticus Inhibition and Aflatoxin Mitigation in Red Pepper Flakes Treated by Pulsed Electric Field Treatment Using Machine Learning and Neural Networks
(Elsevier, 2022-12) Akdemir Evrendilek, Gülsün; Uzuner, Sibel; Bulut, Nurullah; Atmaca, Bahar; Uzuner, Sibel; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Presence of aflatoxins in agricultural products is a worldwide problem. Because of their high heat stability and resistance to most of the food processing technologies, aflatoxin degradation is still a big challenge. Thus, efficacy of pulsed electric fields (PEF) by energies ranging from 0.97 to 17.28 J was tested to determine changes in quality properties in red pepper flakes, mitigation of aflatoxins, inactivation of aflatoxin producing Aspergillus parasiticus, reduction in aflatoxin mutagenity, and modelling of A. parasiticus inactivation in addition to aflatoxin mitigation. Maximum inactivation rate of 64.37 % with 17.28 J was encountered on the mean initial A. parasiticus count. A 99.88, 99.47, 97.75, and 99.58 % reductions were obtained on the mean initial AfG1, AfG2, AfB1, and AfB2 concentrations. PEF treated samples by 0.97, 1.36, 5.76, and 17.28 J at 1 μg/plate, 0.97, 1.92, 7.78, 10.80 J at 10 μg/plate, and 0.97, 1.92, 2.92, 4.08, 5.76, 4.86, 6.80, 9.60, 10.80, and 10.89 J at 100 μg/plate were not mutagenic. Modelling with gradient boosting regression tree (GBRT), random forest regression (RFR), and artificial neural network (ANN) provided the lowest RMSE and highest R2 value for GBRT model for the predicted inactivation of A. parasiticus, whereas ANN model provided the lowest RMSE and highest R2 for predicted mitigation of AfG1, AfB1, and AfB2. PEF treatment possess a viable alternative for aflatoxin degradation with reduced mutagenity and without adverse effect on quality properties of red pepper flakes.
Citation - WoS: 8
Citation - Scopus: 9
Unrevealing the Impact of Pulsed Electric Fields (pef) on Cucumber Seed Vigour and Surface Disinfection
(Sciendo, 2021) Atmaca, Bahar; Uzuner, Sibel; Akdemir Evrendilek, Gülsün; Bulut, Nurullah; Uzuner, Sibel; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Chemicals used for seed treatments help to increase the agricultural production by preventing pests and pathogens but also cause environmental and health problems. Thus, environmentally-friendly technologies need to be developed for a seed treatment that inactivates surface microflora and improves seed vigor. One such pulsed electric field (PEF) treatment applied to cucumber seeds in the range of 1.07-17.28 Joule (J) significantly enhanced a mean germination rate (MGR) by up to 9%, a normal seedling rate by 25.73%, and a resistance to 100 and 200 mM salt stresses by 96% and 91.67%, respectively, with a stronger and faster growth of roots and seedlings. PEF treatment provided 3.34 and 3.22 log-reductions in the surface microflora of total mold and yeast and total aerobic mesophilic bacteria, respectively. The electrical conductivity (EC) values of the control samples increased over time, from 4 to 24 h. Those of the PEF-treated samples after 4, 12, and 24th hours were also more affected by the measurement time not by the PEF treatment. The joint optimization of 18 responses based on the best-fit Gaussian process model pointed to 19.78 s and 17.28 J as the optimal settings. The PEF treatment appeared to improve seed germination ability and stress resistance with the adequate inactivation of surface microflora.