Food Engineering / Gıda Mühendisliği

Permanent URI for this collectionhttps://hdl.handle.net/11147/12

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  • Article
    Citation - WoS: 22
    Citation - Scopus: 27
    Layer-By Assembly of Lysozyme With Iota-Carrageenan and Gum Arabic for Surface Modification of Food Packaging Materials With Improved Barrier Properties
    (Elsevier, 2022) Koca, Nazan; Bayramoğlu, Beste
    The study aimed to investigate the surface modification of biaxially oriented polypropylene (BOPP) by layer-by-layer (LbL) assembly of lysozyme (LZ) with two different polysaccharides, iota-carrageenan (IC) and gum arabic (GA), for food packaging applications. The effects of solution pH, adsorption time, elimination of intermediate drying steps were investigated. The LbL film growth was monitored up to 10 deposition steps by UV–Vis spectroscopy and in situ surface plasmon resonance (SPR). The most successful processing conditions for both types of coatings were pH 7–7 combination with intermediate drying and 20 min adsorption time. SPR pointed out a ‘dissolution/reconstruction’ mechanism in film formation. The thickness and surface morphology of the coatings were characterized by Atomic force microscopy (AFM). The surface roughnesses of LZ/IC coatings were higher than that of LZ/GA coatings indicating a denser matrix in the latter. Deposition of 5 bilayers of LZ/IC and LZ/GA on BOPP resulted in 66.15% and 56.89% reduction in oxygen transmission rate (OTR) of the film, respectively. The corresponding reductions in water vapor transmission rate (WVTR) were 28% and 33.52%, respectively. Elimination of intermediate drying steps resulted in less overall deposition, rougher surfaces, diminished oxygen and water barrier properties. The edible LbL coatings obtained in this study possess good gas barrier properties, which is very promising for their use in the preservation of fresh/fresh-cut produce in combination with modified atmosphere packaging applications. The results promise reduced use of plastic films in food packaging.
  • Article
    Citation - WoS: 9
    Citation - Scopus: 10
    Decontamination of Seeds Destined for Edible Sprout Production From Listeria by Using Chitosan Coating With Synergetic Lysozyme-Nisin Mixture
    (Elsevier, 2020) Sözbilen, Gözde Seval; Yemenicioğlu, Ahmet
    This study aimed at decontamination of seeds destined for edible sprout production from Listeria using chitosan (CS) coatings incorporated with synergetic lysozyme-nisin (LYS-NIS) mixtures. Low molecular weight (LMW) CS coating showed the highest potency against Listeria innocua, followed by medium molecular weight (MMW) and high molecular weight (HMW) CSs. The LMW CS film with LYS-NIS also caused almost 1.5-fold greater log reduction (similar to 5 log) in initial L. innocua load of broth culture than MMW and HMW CS films with LYS-NIS within 6 days. Moreover, LMW CS coating with LYS-NIS reduced the initial Listeria loads of inoculated mung beans, lentils, and wheats by 3.3, 3.4 and 4.1 log, respectively. Antimicrobial coating did not affect seed germination rates considerably. The LYS-NIS addition increased yellowness and opacity of films, and caused limited changes in their mechanical and morphological properties. LMW CS coating with LYS-NIS reduces risk of listeriosis from sprouted seeds.
  • Article
    Citation - WoS: 6
    Citation - Scopus: 7
    An Innovative Design and Application of Natural Antimicrobial Gelatin Based Filling To Control Risk of Listeriosis From Caramel Apples
    (Elsevier, 2020) Kavur, Pelin Barış; Yemenicioğlu, Ahmet
    The aim of this study is to design and apply antimicrobial gelatin based filling with an innovative method in production of safe caramel apples that caused deadly listeriosis cases. For this purpose, water holding capacity and mechanical stability of gelatin (GEL) gels were improved by incorporation of soy proteins (SP) and inulin (IN), respectively. The water activity (a(w)) of gels were also reduced < 0.9 by addition of sucrose (SUC). The application was conducted by coring of apples, filling void core with GEL-SP-IN-SUC blend gel solution containing synergetic antimicrobials, nisin and lysozyme, and antibrowning agent ascorbic acid (each at 1% in gel). Candy sticks were then placed into gel-filled void cores of apples, and apples were kept at 4 degrees C for 20 h for gelation of filling before they were dip-coated with caramel. The inoculated caramel apples with antimicrobial GEL-SP-IN-SUC filling showed 2.4-2.9 D lower Listeria count than traditional inoculated caramel apples during 7-day cold storage. The active blend gel-filling also successfully prevented the discoloration of apple core and accumulation of apple juice between apple surface-caramel coating interface. Mechanical tests showed strong binding of candy sticks by GEL-SP-IN-SUC gel-filling. Active blend gel-filling applied in an innovative way showed good potential to improve safety of candied apples.