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    Automatic colony segmentation on agar surface by image processing
    (Scientific Publishers, 2018) Altuntaş, Volkan; Altuntas, Seda; Gök, Murat
    The Medium (Petri dish, media, agar plate, petri culture, agar culture) are environments that have been formulated for the growth of microorganisms. These structures which are formed by reproduced microorganisms and can be seen by eye are called colony. Colonies formed on the agar, creating images of different morphological characteristics depending on the microorganism and growth media. Colony counting which is required in many applications in areas such as biotechnology and pathology is boring, time consuming and prone to human error process when the large number of colonies counted by hand. In this article, the sample images collected from dairies in the Marmara region are studied on and segmentation methods for separating images of microorganism colonies which is used in the dairy industry for the determination of microbiological analysis of products, have been investigated by the computer-aided image processing techniques such as Otsu, Multi-Otsu, Color K-Means, Watershed, Gabor Filters, Graph Based, Lossy Compression, Random Walker, Texture Filters with proposed comparison method. It was concluded that existing segmentation methods with appropriate parameters can be used to solve this problem and in comparison to other algorithms, Watersheed segmentation algorithm has better performance values than others. © 2018 Scientific Publishers. All rights reserved.
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    Biological activity of optimized phenolic extracts of quince (Cydonia oblonga Miller) parts before and after simulated in vitro gastrointestinal digestion
    (Elsevier Ltd, 2024) Altuntas, Seda; Korukluo?lu, Mihriban
    In this study, the phenolic extracts of Eşme quince parts (pulp, peel, seed, juice, and leaf) were obtained under optimized extraction conditions. Then, the total phenolic content (TPC), the quantities of main phenolic compounds, antioxidant, and antimicrobial activity and the change in bioactivity properties (TPC, antioxidant capacity, and antimicrobial activity on the same sixteen microorganisms) after in vitro digestion of each quince part were evaluated. The order of TPC and antioxidant activity was determined as leaf > peel > juice > pulp > seed. After in vitro gastrointestinal digestion, a decrease was observed for the TPC (average 5-fold reduction) and antioxidant activity (more than 2.5-fold reduction) in all quince parts except quince seed than their extract forms. The quince leaf extract exhibited the highest antibacterial activity. Overall, this study exhibited that the quince leaf was considered a promising, cheap, and natural source for nutritional or pharmaceutical applications with biological activity properties. © 2023 Elsevier Ltd
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    Edible Film and Coating Materials against Fungal Decay
    (CRC Press, 2025) Altuntas, Seda; Terzioglu, Pinar; Cinar, Aycan; Atalay, Zeynep Pinar
    In food preservation, combating fungal decay emerges as one of humanity's most enduring challenges. Fungi, with their voracious appetite and stealthy nature, have long plagued the efforts of humankind to store and distribute food safely. Fungal attack leads to significant losses in food products and poses health risks to consumers due to mycotoxins production (Ortega-Toro et al., 2017). In addition, it is one of the most important reasons for economic losses in the food industry. Therefore, from the earliest civilizations to the modern era, the quest for effective strategies to combat fungal decay has been relentless, leading to the development of various preservation techniques and materials. © 2026 selection and editorial matter, Jian Ju and Fangyuan Zhao; individual chapters, the contributors. All rights reserved.
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    Encapsulated black garlic: Comparison with black garlic extract in terms of physicochemical properties, biological activities, production efficiency and storage stability
    (Elsevier, 2022) Cinar, Aycan; Altuntas, Seda; Demircan, Huseyin; Dundar, Ayse Neslihan; Taner, Gokce; Oral, Rasim Alper
    In this paper, the convenience of encapsulation technique was investigated in terms of characterization of capsule, changing the volatile compounds and preservation biological activity throughout six months for black garlic (BG) by comparison with the aqueous extract which prepared from BG (stored at 4 C) each analysis period. Besides, the genotoxic and antigenotoxic aspects of aqueous black garlic extract (BGE) and black garlic capsule (BGC) developed as a novel promising product were also researched. The S-allyl-L-cysteine (SAC) con-tent, which is mostly known to be responsible for biological activity, was preserved in BGC during six months. The variety of volatile compound of BGC (2 compounds) was significantly reduced compared to BG (17 com-pounds) and BGE (7 compounds), which indicates that the extraction and encapsulation traps the undesirable odor. A significant decrease was observed for total phenolic content and antioxidant capacity (performed with DPPH and CUPric Reducing Antioxidant Capacity (CUPRAC)) of BGC with storage like BGE. In contrast, the values obtained with the ABTS method remained constant with storage. The antimicrobial activity (carried out on five Gram-positive bacteria, three Gram-negative bacteria and three yeasts) of BGC was preserved better than BGE. The treatment concentrations (50, 100, 200 mu g/mL) of both BGE and BGC did not have a genotoxic effect and moreover they have antigenotoxic effects against mitomycin C on human lymphocyte cells. All these results implied that BGC can be good a candidate to increase the consumption of BG providing health benefits and functional supplement for food.
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    Facile fabrication of Ag decorated MnFeO3 catalyst: Comparative analysis of visible light driven antibiotic reduction and antibacterial performance
    (Academic Press Ltd- Elsevier Science Ltd, 2024) Karadirek, Seyda; Tuna, Ozlem; Simsek, Esra Bilgin; Altuntas, Seda; Cinar, Aycan Yigit
    Photocatalysis is an effective method with the potential to eliminate pharmaceutical compounds from water sources. Manganese ferrite (MnFeO3), a type of multiferroic perovskite catalyst, has attracted significant attention due to its small band gap, however its application was limited due to its high recombination rate and low quantum efficiency. It was therefore aimed to improve the properties of MnFeO3 by doping silver (Ag)-particles. In this study, Ag-MnFeO3 photocatalysts with different Ag content (1-3 mmol%) were synthesized by performing a facile hydrothermal method. The as-prepared samples were characterized using x-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDS), transmission electron microscopy (TEM), x-ray photoelectron spectroscopy (XPS), ultraviolet-visible spectroscopy (DRS), photoluminescence spectroscopy (PL), electrochemical impedance spectroscopy (EIS) and Brunauer-Emmett-Teller (BET) method, showing successful addition of Ag-particles with the MnFeO3 structure. Then, the as-synthesized materials were investigated as: (i) photocatalysts for degradation tetracycline (TC) antibiotic and (ii) antibacterial agents for bacteria. The Ag-MnFeO3 catalyst demonstrated superior catalytic performance (95.7%), which was 1.6 times higher than that of pristine MnFeO3 (59.7%). The positive effect was ascribed to oxygen vacancies, enhanced light absorption ability, and lower recombination rate. The Ag-MnFeO3 catalyst also showed satisfactory removal performances in real water matrices. Furthermore, radical trapping tests depicted that the superoxide radicals played a dominant role in the photodegradation system. In addition, Box-Behnken design (BBD) was performed to determine the optimum conditions, which were determined as catalyst dosage of 0.45 g/L, initial TC concentration of 5.10 mg/L, and initial solution pH value of 3.69. In terms of antibacterial tests, the incorporation of Ag into the MnFeO3 structure greatly increased the antimicrobial resistance against bacteria. Our findings disclose that the incorporation of Ag into the MnFeO3 structure can be regarded as a feasible and promising approach to improve both photocatalytic degradation and antibacterial performances.
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    Identification of peptides derived from ripened Mihalic cheese and promising properties: in silico and in vitro approaches
    (Springer, 2025) Altuntas, Seda; Altuntas, Volkan
    Dairy products, particularly fermented ones like cheese, are abundant sources of bioactive peptides (BPs) that hold poten-tial health benefits. This study focuses on investigating the peptide profiles of Mihalic cheese, a traditional Turkish hard-brined cheese, employing both in vitro and in silico approaches. This study compares these two methodologies and assesses the potential of in silico digestion for predicting the bioactive peptide profile of dairy products. The in vitro analysis revealed a significant increase in the number of peptides with lengths of <= 10 amino acids after hydrolysis. While 7.7% of the water-soluble peptide extract (WSPE) fraction contained bioactive peptide sequences comprising more than 20 amino acids, all bioactive peptides detected in the hydrolysate of Mihalic cheese consisted of 7-20 amino acids in length. Furthermore, the in vitro analysis identified 30 peptides with various biological activities such as antioxidant, antimicro-bial, angiotensin-converting enzyme (ACE) inhibitory, DPP-IV inhibitory etc., with beta-CN contributing the most to these bioactive peptides. Despite the potential of in silico methods, there was limited overlap with in vitro findings. While in silico analysis predicted a broader range of bioactive peptides, including 17 ACE-inhibitory peptides, only ten peptides and also only three bioactive peptides were identified by both approaches. While in silico tools are valuable for prediction, they may not fully replicate the complex dynamics of actual enzymatic digestion. This highlights the need to improve results by using more combined in vitro and in silico approaches in studies on the prediction of bioactive peptides in food products.
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    Protective culture: Is it a solution to improve the quality of culture-free white cheese?
    (Wiley, 2022) Eren-Vapur, Ufuk; Cinar, Aycan; Altuntas, Seda
    The biggest problem faced by cheese producers is the textural and microbiological quality of culture-free white cheese types, known as shepherd's cheese or cottage cheese among local people and produced widely throughout Turkey with high heat treatment. In the present study, commercial protective cultures containing two different subspecies of Lactobacillus rhamnosus and Lactobacillus plantarum were added separately to pasteurized milk. Physicochemical, textural, and microbiological properties were analyzed during the processing of cheese and 2 months of ripening. The results showed that L. plantarum was effective on yeast (1.29 log(10) cfu/g reduction) and Staphylococcus aureus growth (1.61 log(10) cfu/g reduction) and L. rhamnosus (one of the commercial cultures) was effective on coliform bacteria (1.70 log(10) cfu/g reduction) compared with the control. Also, the Enterobacteriaceae count was lower than in other protective cultures that used cheese. Overall, the use of L. rhamnosus can be recommended for culture-free white cheese production in this study. Novelty impact statementProtective culture could be a novel approach to inhibit undesirable flora for white brined cheese. In this study, Danisco Holdbac LC culture limited the growth of Enterobacteriaceae and coliform bacteria. Moreover, the addition of Danisco Holdbac LC allowed the textural properties of this type of cheese to be preserved until the end of the ripening period.
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    The role of microencapsulation in maintaining biological activity of royal jelly: comparison with biological activity and bioaccessibility of microencapsulated, fresh and lyophilized forms during storage
    (Wiley, 2022) Dundar, Ayse Neslihan; Cinar, Aycan; Altuntas, Seda; Ulubayram, Neslihan; Taner, Gokce; Dagdelen, Adnan Fatih; Oral, Rasim Alper
    BACKGROUND Royal jelly (RJ) is a unique beehive product and has been recommended for human health since ancient times because of its antioxidant, antimicrobial, antiproliferative, neuroprotective, anti-lipidemic and anti-aging features. However, the biggest obstacle in the use of RJ is the need for cold storage and the instability of bioactive components over time. In the present study, 10-hydroxy-2-decenoic acid (10-HDA) content, as well as antioxidant [using 1,1-diphenyl-2-picrylhydrazy and 2,2 '-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) methods] and antimicrobial activity (five Gram-positive, five Gram-negative and three yeasts), were comparatively evaluated for three RJ forms, two of which can be stored at 24 +/- 1 degrees C during storage. RESULTS Microencapsulated royal jelly (MRJ) stored at room temperature succeeded in preserving its 10-HDA content, a major bioactive compound, during the 6 months, with respect to lyophilized royal jelly (LRJ) and fresh RJ stored at 4 degrees C. The initial 10-HDA contents of RJ, LRJ and MRJ were determined as 1.90%, 5.26% and 2.75%, respectively. Moreover, the total phenolic content, antioxidant capacity and antimicrobial activity mostly remained constant throughout the storage period (P >= 0.05). Gram-positive strains were generally more sensitive than Gram-negative strains. In the present study, the in vitro simulated digestion analysis showed that MRJ can tolerate the digestion process. CONCLUSION Overall, the encapsulation process was considered as one preservative technique for RJ. The microencapsulation of RJ as shown in the results of the present study are encouraging in terms of enabling the local beekeeping sector to achieve ease of production and increased product diversity. MRJ shows promise as a commercial product with a high export value for producers. (c) 2022 Society of Chemical Industry.