Development of nanofiber based active packaging material by electrospinning technique and food validation

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Tezin Türü: Doktora

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Fen Bilimleri Enstitüsü, Türkiye

Tezin Onay Tarihi: 2019

Tezin Dili: İngilizce

Öğrenci: AYÇA AYDOĞDU

Asıl Danışman (Eş Danışmanlı Tezler İçin): Servet Gülüm Şümnü

Eş Danışman: Serpil Şahin

Özet:

The main objective of this study was to encapsulate gallic acid in Hydroxypropyl methylcellulose (HPMC) and legume flours (lentil and pea) based nanofiber by electrospinning and to examine the usage of nanofibers as active packaging materials. Firstly, HPMC based homogenous nanofibers were fabricated and it was observed that the morphology of the fibers changed from the beaded structure to the uniform fiber structure by increasing the concentrations of the solutions. By choosing optimum HPMC concentration, gallic acid was encapsulated successfully in HPMC based nanofibers by electrospinning and the antioxidant activity of gallic acid were preserved in the nanofibers. When gallic acid loaded HPMC nanofiber was used as active package material to pack walnut, it reduced the oxidation of walnut during storage. Then, gallic acid was encapsulated into lentil flour/polyethylene oxide (PEO) nanofibers. To promote the solubility of lentil proteins, pH of solutions was adjusted to pH 1 and pH 10. It should be noted that alkaline nanofibers showed homogenous structure and antioxidant activity after electrospinning. Therefore, alkaline nanofibers were used to pack walnuts and active packages provided stability to walnuts against oxidation. Moreover, gallic acid was also incorporated into pea flour nanofiber successfully. To prove incorporation of gallic acid into nanofibers, physical and thermal properties of gallic acid encapsulated nanofibers were examined by Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA) and differential scanning calorimeter (DSC) analyses. Finally, bilayer nanofiber sheets composed of Poly (lactic acid) (PLA) and soy protein/HPMC were produced to be suggested to pack of light sensitive foods.