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Prebiotic Oligosaccharide Production From Hazelnut Wastes
(Izmir Institute of Technology, 2017) Sürek, Ece; Büyükkileci, Ali Oğuz; Büyükkileci, Ali Oğuz; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Turkey is the world leader in hazelnut production and a large amount of wastes is produced during its harvesting and processing. Obtaining valuable products from hazelnut by-products can add value to those. In this study, xylooligosaccharide (XOS), which has prebiotic potential and not manufactured in Turkey, was selected as the target product. Hazelnut wastes (shell, green leafy cover and pruning wastes) are suitable sources for production of XOS. Although there are some studies on valorization of hazelnut wastes, there is no study about XOS production. In this study, xylan in the shell was hydrolyzed to XOS by autohydrolysis and enzymatic hydrolysis at different conditions. The highest XOS yield was obtained as 62.93% after autohydrolysis at 190 oC for 5 min. The content of XOS with low degree of polymerization (DP<6) increased from 10.13 to 32.74% after hydrolysis with xylanase. XOS from enzymatic hydrolysis was purified by ultrafiltration through 10 and 2 kDa size membranes. The percent of low DP-XOS in liquor was increased after ultrafiltration; however monomers could not be separated. Prebiotic activity and stability of XOS were determined under different conditions. The growth of probiotic bacteria was observed after in vitro fermentation of XOS. XOS showed a good stability to food production and gastrointestinal digestion conditions. The objective of this study was to produce of a high value product such as XOS with prebiotic potential from hazelnut wastes by autohydrolysis and enzymatic hydrolysis. This study was highly original since XOS has been produced from hazelnut wastes for the first time.
Polysaccharide Based Packaging Film for Fresh Cut Produce
(Izmir Institute of Technology, 2017) Şamlı, Merve; Harsa, Hayriye Şebnem; Büyükkileci, Ali Oğuz; Harsa, Hayriye Şebnem; Büyükkileci, Ali Oğuz; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
In this thesis, agro industrial wastes such as bracts and leaves of artichoke were used to develop biodegradable packaging materials for fresh-cut artichokes. As flim forming materials; cellulose, hemicellulose, lignin and wax fractions were extracted by using mild alkaline treatment applied to artichoke wastes. Carboxy methyl cellulose was chemically synthesized from extracted cellulose fiber. A mechanical process (Masuko Supermasscolloider, at-100 um grind size via 5 times feeding) with minimum environmental impact was selected to obtain cellulose micro fibrils with micro sized dimensions (50-200 um in length and 10-30 um in width).These fractions used as polysaccharide sources in film forming solutions. Different combinations of these polysaccharide based film materials were optimized using General Factorial Design and four film combinations were selected among the films produced.elected films were MFC and CMC based having good elasticity (16 % strain), tensile strength and low gas permeability properties (150mlO2/m2.day).Different concentrations of additives such as wax, stearic acid, chitosan were used with the glycerol addition of plasticizer. SEM analyses of selected films showed films showed films having smooth surface and dense structure by looking their cross sectional area. Thermal analyses proved sealabilitiy of films obtained by extracted fractions from artichoke at 200-250 oC temperature intervals. But, presence of MFC in films hindered the heat sealing ability. Therefore, MFC and CMC based films successfully showed optimal properties when they were combined with glycerol, stearic acid and wax.

Phd Degree / Doktora

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