Food Engineering / Gıda Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/12
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Article Citation - WoS: 17Citation - Scopus: 18Incorporation of Organic Acids Turns Classically Brittle Zein Films into Flexible Antimicrobial Packaging Materials(Wiley, 2022) Sozbilen, G.S.; Çavdaroğlu, E.; Yemenicioglu, A.This study aimed to turn classically brittle zein films into flexible antimicrobial ones by the use of lactic (LA), malic (MA) and tartaric acids (TA). The most effective plasticizer was LA (400% elongation at break [EB] at 4%), while MA (189% EB at 4.5%) and TA (68% EB at 5%) showed moderate and limited plasticizing effects, respectively. The LA- and MA-loaded films maintained their flexibility during 30-day storage at 4°C or 25°C. Fourier transform infrared (FTIR) analysis suggested that the plasticization of LA and MA could be related to secondary structural changes in zein such as increased α-helix and random coils (mainly by MA) and spaced/modified intermolecular (only by LA) and intramolecular (mainly by MA) β-sheets. Atomic force and scanning electron microscopy showed that LA and MA gave more homogenous and smoother films than TA. Films with LA showed the highest water vapour permeability followed by those of control, MA- and TA-loaded films. Films with 3%–4% LA or MA formed clear zones on Listeria innocua and Klebsiella pneumonia, but only films with LA formed clear zones on Escherichia coli. All OA-loaded films gave unclear zones on Staphylococcus aureus in disc-diffusion tests, but this bacterium was inactivated rapidly in antimicrobial tests based on surface inoculation tests. LA is the best OA to develop flexible antimicrobial films from zein, an industrial by-product that films could not have been utilized as a widespread packaging material due to their brittleness. © 2021 John Wiley & Sons, Ltd.Article Citation - WoS: 39Citation - Scopus: 41Novel Edible Films of Pectins Extracted From Low-Grade Fruits and Stalk Wastes of Sun-Dried Figs: Effects of Pectin Composition and Molecular Properties on Film Characteristics(Elsevier, 2023) Çavdaroğlu, Elif; Büyüktaş, Duygu; Farris, Stefano; Yemenicioğlu, AhmetThis study aimed to explore the characteristics of novel fig pectin films. For this purpose, films of crude fig pectin (CFP) extracted from low-grade sun-dried fruits and films of crude (CSP) and purified (PSP) stalk pectins extracted from stalk waste of processed high-quality sun-dried figs were evaluated for their physicochemical properties. The properties of pristine (CFP, CSP, and PSP films) and CaCl2 cross-linked films (CFP–Ca++, CSP-Ca++and PSP-Ca++ films) of fig pectins were also compared with films of commercial citrus (CP and CP-Ca++) and apple (AP, AP-Ca++) pectins. The cross-linking improved the mechanical strength and barrier properties of most films. CP, CP-Ca++, PSP, and PSP-Ca++ films showed greater mechanical strength and stiffness than other films. PSP-Ca++, PSP and CP-Ca++ films showed the lowest water vapor permeability (6.28, 12.85, 14.96 g.mm.m−2.day−1.kPa−1, respectively) while CSP-Ca++, CP-Ca++, CP, PSP-Ca++ films showed the lowest oxygen permeability coefficients (5403, 8265, 10776, 11124 mL.μm.m−2.24h−1.atm−1, respectively). All cross-linked fig pectin films showed 2–3 fold lower degree of swelling than CP-Ca++ film. The CFP-Ca++ film showed the highest surface hydrophobicity (contact angle = 101.8°) but the lowest water solubility (32.8%) and degree of swelling. Analysis of Pearson's correlations between pectin properties and film characteristics revealed that galacturonic acid (GA) content affects the mechanical properties, while GA content, degree of esterification (DE), and acetylation affect the moisture barrier performance; finally, GA content and DE affect the oxygen barrier performance of pectin films. Films of stalk waste pectins showed some properties beyond the limits of those obtained from commercial pectins.Article The Use of Organic Sun-Dried Fruits for Delivery of Phenolic Compounds(İzzet KARA, 2022) Dervişoğlu, Gökhan; Yemenicioğlu, AhmetThe aim of this study is to characterize and increase the total soluble (water soluble + alcohol soluble) phenolic (SPCT) and flavonoid content (SFCT) and total soluble free radical scavenging based antioxidant capacity (SACT) of major sun-dried fruits such as raisins, figs, prunes and apricots. Due to their high insoluble dietary fiber content, the bound antioxidant capacity formed 61 to 67% of the overall antioxidant capacity (water soluble + alcohol soluble + bound) of sun-dried fruits. The SPCT, SFCT and SACT of sun-dried fruits changed between 1675 and 3860 μg catechin/g (d.w.), 161 and 495 μg catechin/g (d.w.) and 13 and 28.5 μmol Trolox/kg (d.w.), respectively. The incorporation of green tea polyphenols into sun-dried raisins, figs and apricots by controlled rehydration conducted in green tea extracts increased their SPCT, SFCT and SACT 1.5 to 1.8 fold, 1.3 to 1.6 fold, and 1.5 to 2.6 fold, respectively. The method applied caused limited increases in SPCT (1.1 fold) and SFCT (1.2 fold) of prunes, but it increased SACT of these fruits 1.6 fold. This study showed the possibility of using sun-dried fruits not only as source of dietary fiber, but also for delivery of phenolic compounds. The methods used in this study for delivery of green tea phenolic compounds to selected organic sun-dried fruits could be an alternative method to increase intake of these invaluable antioxidant compounds and increase functionality of sun-dried fruits which are already accepted as good source of dietary fiber.Article Citation - WoS: 17Citation - Scopus: 21Utilization of Stalk Waste Separated During Processing of Sun-Dried Figs (ficus Carica) as a Source of Pectin: Extraction and Determination of Molecular and Functional Properties(Academic Press Inc., 2022) Çavdaroğlu, Elif; Yemenicioğlu, AhmetThis study aimed the utilization of fig stalk waste as an alternative pectin source. For this purpose, the characteristics of extracted stalk waste pectin (SP) were compared with those of citrus pectin (CP) and pectin extracted from defected substandard whole sun-dried figs (FP). The SP had a higher extraction yield (11.7%) than FP (9.4%). The galacturonic acid content and degree of esterification of SP (32.3 and 50.1%) were higher than those of FP (19.9 and 38.8%), but lower than those of CP (79.3 and 56.2%), respectively. The SP and CP had different sugar compositions (D-glucose, L-rhamnose, D-galactose and L-arabinose) and weight average molecular weights, but similar FTIR profiles. The SP showed almost 1.9 and 1.6-fold higher Trolox equivalent antioxidant capacity (TEAC), and 2.7 and 2.0-fold higher water absorption capacity than CP and FP, respectively. SP at 3% (w/w) showed the second highest viscosity after CP and the highest emulsion stability. Gels of SP and CP at 1.75–3% range had similar firmness, but SP formed more fracturable gels than CP. Sun-dried fig stalk waste is a better source of pectin than defected substandard whole sun-dried figs. The SP could be utilized to develop functional food with alternative textural and rheological properties.Article Citation - WoS: 1Orta Nemli İncirlerde Depolama Sonrasında Pektin Metil Esteraz Aktivitesi Değişimi(Pamukkale Üniversitesi, 2015) Demirbüker Kavak, Dilek; Yemenicioğlu, AhmetOrta nemli meyveler, kurutulmuş meyvelerin rehidre edilmesiyle elde edilebilmektedirler. Kuru meyvelere kıyasla doğrudan tüketime daha uygun olan orta nemli meyveler, sanayide unlu mamüller, süt ürünleri, şekerlemeler kullanılabilmektedirler. Bu çalışmanın amacı orta nemli hale getirilmiş incirlerin 3 aylık depolama süresi sonucunda mikrobiyal stabilitelerinin ve dokuda yumuşamaya neden olan pektin metil esteraz enzimi (PME) aktivitelerinin kıyaslanmasıdır. Bu amaçla kuru incirler 30°C ve 80°C'de suyla %30 nem içeriğine ulaşana kadar rehidre edilmişlerdir. Rehidre edilmiş örnekler, 3 ay süreyle +4°C'de depolanmışlardır. Depolama süresi sonunda toplam canlı sayımı sonuçlarına göre 30°C kontrol örnekleri ile 80°C'de rehidre edilmiş örnekler arasında istatistiksel olarak anlamlı bir fark bulunmamıştır. Depolama süresi sonucunda PME aktivitesi, kontrol örnekleri için 24.1 ?mol COOH dk-1g-1 iken, 80°C'de rehidre edilmiş orta nemli incirlerde 17.4 ?mol COOH dk-1g-1bulunmuştur. Sonuç olarak incirleri orta nemli hale getirmek için 80°C'de gerçekleşen rehidrasyon işlemi, depolama sonrası mikrobiyal yükü belirgin şekilde etkilememesine karşın, yumuşamaya neden olan PME aktivitesini 30°C'de rehidre edilmiş kontrol örneklerine kıyasla %28 oranında azaltmaktadır.Article Siyah Meyveli İncir Çeşitlerinin Kurutularak Değerlendirilmesi(Pamukkale Üniversitesi, 2015) Konak, Ramazan; Kösoğlu, İlknur; Tan, Nilgün; Kocataş, Hilmi; Yemenicioğlu, Ahmetİncir, yüksek oranda diyet lif, fenolik madde ve mineralleri içeren bir meyvedir. Ülkemizin sahip olduğu zengin incir mirası göz önüne alındığında antioksidan kapasitesi çok yüksek, renkli çeşitler mevcut olmasına rağmen bunların kurutularak değerlendirilme uygulamaları yok denecek kadar azdır. Bu çalışma ile İncir Araştırma Enstitüsü genetik kaynaklar parselinde bulunan siyah renkli çeşitlerden 9 tanesi ve standart kurutmalık çeşitler olan Sarılop ve Sarızeybek çeşitleri kullanılmıştır. Meyveler geleneksel yönteme göre kerevetler ile güneş altında kurutulup çeşitlerin kuruma kapasiteleri ve kuru meyve kaliteleri tespit edilmiştir. Standart kurutmalık çeşitlerin yanı sıra 1101, 1102 ve 1012 kod numaralı siyah renkli çeşitlerin kurutmaya uygun olduğu sonucuna varılmıştır.Other Sıcaklık ve Sürenin Havuç ve Yeşil Fasulyelerde Bulunan Pektin Metilesteraz Enzimi Üzerindeki Etkisinin Belirlenmesi(Gıda Teknolojisi Derneği, 2003) Yemenicioğlu, Ahmet; Cemeroğlu, BekirHavuç ve yeşil fasulyelerden elde edilmiş ekstrakte ve homojenatlarda PME enziminin aktivite düzeyi ve termal karakteristikleri belirlenmiştir. Yeşil fasulyelerden elde edilmiş homojenatlarda havuçlara kıyasla 2.6 kat daha fazla PME aktivitesi bulunduğu saptanmıştır. Çözünür, iyonik ve kovalent bağlı PME fraksiyonlarının yüzde dağılımı y. fasulyelerde sırasıyla; 3, 88,9 ve havuçlarda 0,81, 19 düzeyinde olduğu belirlenmiştir. Homojenatlarda bulunan PME enzimlerinin optimum sıcaklıkları y. fasulylerde; 40$^circ$C, buna karşın havuçlarda; 50$^circ$C'dır. Her iki sebzede de iyonik olarak bağlı PME enzimleri, benzer termal karakteristiklere sahip olup 40$^circ$C'de optimum aktivite göstermektedir. Buna karşın kovalent bağlı enzim fraksiyonunun optimum sıcaklığı, havuçlarda 55$^circ$C, y. fasulyelerde 50$^circ$C dır.Article Citation - WoS: 64Citation - Scopus: 77Development of Flexible Antimicrobial Zein Coatings With Essential Oils for the Inhibition of Critical Pathogens on the Surface of Whole Fruits: Test of Coatings on Inoculated Melons(Elsevier, 2019) Boyacı, Derya; Iorio, Gianmarco; Sözbilen, Gözde Seval; Alkan, Derya; Trabattoni, Silvia; Pucillo, Flavia; Yemenicioğlu, AhmetThis study aimed to develop essential oil (EO)-containing antimicrobial coatings for the inhibition of pathogenic bacteria contamination on fruit peels. Incorporation of eugenol (EUG), carvacrol (CAR), and thymol (THY) into films at > 1% (w/w) eliminated the typical brittleness of zein films. However, EUG outperformed CAR and THY in terms of mechanical properties. Films with >= 2% (w/w) CAR and THY and >= 3% EUG showed clear zones against L. innocua and E. coli in agar medium at 37 degrees C. All EO-containing films also inhibited L. innocua and E. coli inoculated at their surfaces by minimum 3.9 and 2.7 decimal (D) within 1 day at 10 degrees C. Moreover, 2% EUG-containing zein coatings caused 2-3 decimal reduction in L. innocua and E. coli counts of inoculated melon surfaces at 10 degrees C. Unlike the bare zein coatings, flexible EUG-containing films on melons did not show cracking or detachment. Zein films loaded with EUG showed a highly hydrophilic surface. The best oxygen barrier performance was observed for the EUG-richest formulation (i.e., EUG at 3%), and this was attributed to a homogenizing effect of the EO that eventually led to a denser and hole-free network. This work suggested that flexible coatings of zein containing EOs could inhibit pathogens embedded in the rough peel surface of melons.Editorial Citation - WoS: 5Citation - Scopus: 7Natural Hydrocolloids in the Food Sector - Recent Applications Beyond Conventional Uses(Wiley, 2020) Yemenicioğlu, Ahmet; Farris, Stefano; Türkyılmaz, Meltem; Güleç, ŞükrüIn food industry, natural hydrocolloids have been extensively used to increase the functionality of different food products such as beverages, bakery and confectionery, sauces and dressings, and meat and poultry. Conventional applications of hydrocolloids in the food industry are still based on their rheological and surface‐active properties (Dickinson, 2018; Nishinari et al., 2018; Yousefi & Jafari, 2019). However, recent developments in the hydrocolloids sector fuelled by sophisticated market demands and emerging new technologies expanded the applications of hydrocolloids beyond their conventional uses.Book Part Strategies for Controlling Major Enzymatic Reactions in Fresh and Processed Vegetables(Taylor & Francis, 2016) Yemenicioğlu, Ahmet[No abstract available]