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 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: 15Citation - Scopus: 21Development of Pectin-Eugenol Emulsion Coatings for Inhibition of Listeria on Webbed-Rind Melons: a Comparative Study With Fig and Citrus Pectins(John Wiley and Sons Inc., 2020) Çavdaroğlu, Elif; Farris, Stefano; Yemenicioğlu, AhmetThe objective of this study was to employ pectin-based antimicrobial coatings for inhibition of Listeria on surfaces of whole webbed-rind melons that cause frequent outbreaks of listeriosis. For this purpose, emulsion-based coatings were developed using citrus pectin (CPEC) or pectin extracted from processing wastes of sun-dried figs (FPEC) and eugenol (EUG). The emulsions of FPEC and CPEC with EUG (droplet size range: 1.99-11.22 mu m) were highly stable for minimum 10 days at 10 degrees C. The FPEC-EUG films showed higher flexibility and degree of wettability than CPEC-EUG films. In contrast, CPEC-EUG films had a higher gas barrier performance against oxygen at 50% relative humidity than FPEC-EUG films. The zone inhibition tests showed that FPEC-EUG films are more effective against Listeria innocua than CPEC-EUG films. However, FPEC and CPEC coatings with 2% EUG caused 2.2 and 2.7 decimal inactivation of Listeria on Galia melons within 1 week, respectively. The pectin coatings with EUG could reduce the risk of listeriosis from webbed-rind melons.