Yazar "Hosoglu, Muge Isleten" seçeneğine göre listele

Listeleniyor 1 - 8 / 8
  • [ X ]
    Öğe
    Aroma characterization of five microalgae species using solid-phase microextraction and gas chromatography-mass spectrometry/olfactometry
    (Elsevier Sci Ltd, 2018) Hosoglu, Muge Isleten
    In this study, aroma compounds produced by three marine microalgae species (Crypthecodinium cohnii, Schizochytrium limacinum and Tetraselmis chuii) and two fresh water microalgae (Chlorella vulgaris and Chlorella protothecoides) important for nutritional applications were identified by means of solid-phase microextraction followed by gas chromatography-mass spectrometry (GC-MS), GC-olfactometry (GCO) and a sensory panel. Principal components analysis (PCA) was applied to the instrumental and sensory analysis data to visualize differences between the samples in terms of descriptive attributes and volatile compounds. Accordingly, C. cohnii was characterised by a high level of sulfur compounds (dimethyl sulfide, ethanethiol), and ester and alcohol compounds associated with distinct 'sulfur-cabbage', 'fruity', 'rosy', and 'boiled potato' aroma notes. While S. limacinum was characterised more by aldehydes and alcohol compounds associated with 'mushroom', 'cucumber', and 'fatty-grassy' aroma characteristics, the other three samples showed relatively higher levels of ketone and terpene compounds with 'woody' and 'cereal-like' sensory characteristics.
  • [ X ]
    Öğe
  • [ X ]
    Öğe
    Bioflavour production from tomato and pepper pomaces by Kluyveromyces marxianus and Debaryomyces hansenii
    (Springer, 2015) Guneser, Onur; Demirkol, Asli; Yuceer, Yonca Karagul; Togay, Sine Ozmen; Hosoglu, Muge Isleten; Elibol, Murat
    Bioflavours are called natural flavour and/or fragrance compounds which are produced using metabolic pathway of the microorganism and/or plant cells or their enzyme systems with bioengineering approaches. The aim of this study was to investigate bioflavour production from tomato and red pepper pomaces by Kluyveromyces marxianus and Debaryomyces hansenii. Obtained specific growth rates of K. marxianus and D. hansenii in tomato pomace were 0.081/h and 0.177/h, respectively. The bioflavour profile differed between the yeasts. Both yeasts can produce esters and alcohols such as phenyl ethyl alcohol, isoamyl alcohol, isoamyl acetate, phenyl ethyl acetate and isovaleric acid. Tarhana and rose were descriptive flavour terms for tomato and pepper pomaces fermented by K. marxianus, respectively. Tomato pomace fermented by D. hansenii had the most intense green bean flavour while fermented vegetable and storage/yeast were defined as characteristic flavour terms for pepper pomaces fermented by D. hansenii.
  • [ X ]
    Öğe
    ENGINEERING OF MILK-BASED BEVERAGES: CURRENT STATUS, DEVELOPMENTS, AND CONSUMER TRENDS
    (Woodhead Publ Ltd, 2019) Guneser, Onur; Hosoglu, Muge Isleten; Guneser, Buket Aydeniz; Yuceer, Yonca Karagul
    [Anstract Not Available]
  • [ X ]
    Öğe
    Fermented Spirulina products with Saccharomyces and non- Saccharomyces yeasts: Special reference to their microbial, physico-chemical and sensory characterizations
    (Elsevier, 2022) Sahin, Busra; Hosoglu, Muge Isleten; Guneser, Onur; Karagul-Yuceer, Yonca
    Innovative products produced from various sources through fermentation processes have been a resurgence of interest. This study was designed to determine the performance of fermented Spirulina (FS) products by three different yeast species including Debaryomyces hansenii, Kluyveromyces marxianus and Saccharomyces cerevisiae and investigate the microbial, physicochemical and sensory characteristics of products. The results showed that the increase in yeast cell number was around 3 log after 48 h fermentation in Spirulina medium without additional carbon source. Protein bands with a molecular weight of-51 kDa seemed less visible and bands 14-22 kDa disappeared after 48 h fermentation by K. marxianus showed strong hydrolysis of proteins during fermentation. The amino acid compositions of the three kinds of FS were different also compared to unfermented Spirulina (unFS). Glutamic acid, methionine, lysine, isoleucine and valine became more dominant in FS samples. According to GC-MS analysis, there was a decrease in the concentration of pyrazine, ketone and aldehyde compounds of FS compared to unFS. The flavor notes of seaweed, cardboard, earthy/muddy and cereal/ straw were found to be the highest in unFS than in FS detected by panelists during sensory evaluations. FS by K. marxianus is highly characterized as having the lowest seaweed and umami flavor attributes and higher fermented and rose attributes. Finally, the current study revealed that the potential of Spirulina biomass to be a suitable substrate for yeasts and fermentation of Spirulina with different yeast species led to different kinds of products.
  • [ X ]
    Öğe
    Optimizing bioreactor conditions for Spirulina fermentation by Lactobacillus helveticus and Kluyveromyces marxianus: Impact on chemical & bioactive properties
    (Elsevier Sci Ltd, 2024) Yay, Cansu; Cinar, Zeynep Ozlem; Donmez, Serhat; Tumer, Tugba Boyunegmez; Guneser, Onur; Hosoglu, Muge Isleten
    This study focused on optimizing the production of fermented Spirulina (FS) products using a bioactivity-guided strategy with Lactobacillus helveticus B-4526 and Kluyveromyces marxianus Y-329 in a 3-L bioreactor. Various operating conditions, including aeration rates and pH modes, were tested. While both microorganisms thrived under all conditions, the cascade mode, controlling dissolved oxygen, enhanced protein hydrolysis and antioxidant activity, as confirmed by SDS-PAGE and DPPH/TEAC assays, respectively. Screening revealed that cascade FS significantly decreased viability of colon cancer cells (HT-29) in a dose-dependent manner, with up to a 72 % reduction. Doses <= 500 mu g mL- 1 of cascade FS proved safe and effective in suppressing NO release without compromising cellular viability. Additionally, cascade FS exhibited diverse volatile organic compounds and reducing the characteristic seaweed aroma. These findings highlight cascade FS as a promising alternative food source with improved bioactive properties, urging further exploration of its bioactive compounds, particularly bioactive peptides.
  • [ X ]
    Öğe
    Production of flavor compounds from olive mill waste by Rhizopus oryzae and Candida tropicalis
    (Soc Brasileira Microbiologia, 2017) Guneser, Onur; Demirkol, Asli; Yuceer, Yonca Karagul; Togay, Sine Ozmen; Hosoglu, Muge Isleten; Elibol, Murat
    The purpose of this study was to investigate the production of flavor compounds from olive mill waste by microbial fermentation of Rhizopus oryzae and Candida tropicalis. Olive mill waste fermentations were performed in shake and bioreactor cultures. Production of flavor compounds from olive mill waste was followed by Gas Chromatography Mass spectrometry, Gas chromatography- olfactometry and Spectrum Sensory Analysis. As a result, 1.73-log and 3.23-log cfu/mL increases were observed in the microbial populations of R. oryzae and C. tropicalis during shake cultures, respectively. C. tropicalis can produce a higher concentration of n-limonene from olive mill waste than R. oryzae in shake cultures. The concentration of n-limonene was determined as 185.56 and 249.54 mu g/kg in the fermented olive mill waste by R. oryzae and C. tropicalis in shake cultures respectively. In contrast, R. oryzae can produce a higher concentration of n-limonene (87.73 mu g/kg) n-limonene than C. tropicalis (11.95 mu g/kg) in bioreactor cultures. Based on sensory analysis, unripe olive, wet towel, sweet aromatic, fermented aromas were determined at high intensity in olive mill waste fermented with R. oryzae meanwhile olive mill waste fermented with C. tropicalis had only a high intensity of unripe olive and oily aroma. (C) 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda.
  • [ X ]
    Öğe
    Production of flavor compounds from rice bran by yeasts metabolisms of Kluyveromyces marxianus and Debaryomyces hansenii
    (Springer, 2022) Guneser, Onur; Yuceer, Yonca Karagul; Hosoglu, Muge Isleten; Togay, Sine Ozmen; Elibol, Murat
    The aim of this study was to evaluate the biosynthesis of flavor compounds from rice bran by fermentation facilitated by Kluyveromyces marxianus and Debaryomyces hansenii. The growth of both yeasts was assessed by specific growth rates and doubling time. The biosynthesis of flavor compounds was evaluated by gas chromatography-olfactometry (GC-O), gas chromatography-mass spectrometry (GC-MS), and Spectrum (TM) sensory analysis. The specific growth rate (mu) and doubling time (t(d)) of K. marxianus was calculated as 0.16/h and 4.21h, respectively, whereas that of D. hansenii was determined as 0.13/h and 5.33h, respectively. K. marxianus and D. hansenii produced significant levels of higher alcohols and acetate esters from rice bran. Results showed that K. marxianus can produce 827.27 mu g/kg of isoamyl alcohol, 169.77 mu g/kg of phenyl ethyl alcohol, and 216.08 mu g/kg of phenyl ethyl acetate after 24-h batch fermentation. A significant amount of isovaleric acid was also synthesized by K. marxianus (4013 mu g/kg) after the batch fermentation of 96 h. 415.64 mu g/kg of isoamyl alcohol and 135.77 mu g/kg of phenyl ethyl acetate was determined in rice bran fermented by D. hansenii after 24-h fermentation. Fermented cereals and rose were the characteristic flavor descriptors of the fermented rice bran samples. Rose flavor in fermented rice bran samples was found to be associated with phenyl ethyl alcohol, phenyl ethyl acetate, isoamyl acetate, and guaiacol. Thus, the findings of this study demonstrate that the valorization of rice bran can be achieved with the production of natural flavor compounds by yeast metabolism.