Nişasta Bazlı Köpük Tabakların Hidrofobik Malzemelerle Kaplanması

Hafif ve ucuz olması nedeniyle genleştirilmiş polistiren (EPS) tabaklar gıdaların ambalajlanması ve servisinde yaygın olarak kullanılmaktadır. Fakat çevre üzerindeki olumsuz etkilerinden dolayı dünyanın pek çok yerinde kullanımı yasaklanmaya veya kısıtlanmaya başlanmıştır. Son yıllarda biyobozunur köpük tabak üretimi üzerine pek çok çalışma yapılmaktadır. Nişasta bazlı köpük tabaklar biyobozunur olması ve yeterince mekanik dirence sahip olması açısından büyük umut vadetse de suya karşı yeterince direnç gösterememesi, ticari olarak kullanımının yaygınlaşmasındaki en önemli engeldir. Bu çalışmada buğday nişastası, buğday-patates nişastası karışımı glioksal ile çapraz bağlandıktan sonra nişastanın %7’si kadar buğday lifi eklenerek köpük tabaklar üretilmiştir. Köpük tabaklar polilaktik asit (PLA), polikaprolakton (PKL) ve polimetil metakrilat (PMMA) çözeltileri kullanılarak kaplanmıştır. Taramalı elektron mikroskobu görüntüleri, kaplama malzemelerinin köpük tabakların yüzeyinde 30-40 µm kalınlığında bir katman oluşturduğunu ve tabak yüzeyini daha pürüzsüz bir hale getirdiğini göstermiştir. Buğday-patates nişastasından üretilen köpük tabakların ortalama yoğunluğu 0.120±0.01 g/cm3 olup buğday nişastasından üretilen tabaklarınkinden (0.157±0.02 g/cm3) daha düşük olduğu bulunmuştur. PKL ve PLA ile buğday nişastasından, PLA ve PMMA ile buğday-patates nişastasında üretilen tabakların kaplanması, tabakların yoğunluğunu değiştirmemiştir. PLA ve PMMA ile kaplanan köpük tabakların kontrole göre sırasıyla 12 ve 18 kat daha az su emdiği bulunmuştur. PMMA ile kaplanan, buğday-patates nişastasından üretilen tabakların 300 dakika sonra sadece %2.3 oranında su emmesi özellikle su içeriği yüksek gıdaların ambalajlanması için uygun olduğunu göstermiştir. Simüle toprak altında PKL ile kaplanan tabaklar 42. günde, PLA ile kaplananlar 84. günde parçalanarak toprağa karıştığı bulunmuştur. PMMA ile kaplan tabakların 84. günde başlangıçtaki tabak ağırlığının %12.2’sinin parçalanmadan kaldığı tespit edilmiştir.

Anahtar Kelimeler:

Köpük tabak, Nişasta, Polikaprolakton, Polilaktik Asit, Polimetil metakrilat, Foam tray, Starch, Polycaprolactone, Polylactic Acid, Polymethyl methacrylate

Coating Starch-Based Foam Trays with Hydrophobic Materials

Expanded polystyrene (EPS) trays are widely used for food packaging and serving because they are light and inexpensive. However, their use has been banned or restricted in many parts of the world due to its negative effects on the environment. In recent years, many studies have been carried out on the production of biodegradable foam trays. Although starch-based foam trays are promising in terms of being biodegradable and having sufficient mechanical resistance, the most important obstacle in their commercial use is that they are not sufficiently resistant to water. In this study, foam trays were produced by adding wheat fiber at a ratio of 7% of starch after wheat starch or mixture of wheat-potato starch was cross-linked with glyoxal. Foam trays were coated by using solutions of polylactic acid (PLA), polycaprolactone (PKL), and polymethyl methacrylate (PMMA). Scanning electron microscope images showed that coating materials formed a 30-40 µm thick layer on the surface of foam trays and making the surface of trays smoother. The average density of foam trays produced from wheat potato starch was 0.120±0.01 g/cm3, which was lower than that of trays produced from wheat starch (0.157±0.02 g/cm3). The coating of trays produced from wheat starch with PKL and PLA, and wheat-potato starch with PLA and PMMA did not change the density of trays. Foam trays coated with PLA and PMMA absorbed 12 and 18 times less water than control trays, respectively. The trays made of wheat-potato starch coated with PMMA absorbed only 2.3% of water after 300 minutes, showing that they could be particularly suitable for packaging foods with a high water content. Trays coated with PCL under simulated soil were found to break down on the day 42, and those coated with PLA on the day 84. It was determined that 12.2% of the initial tray weight of trays coated with PMMA remained intact on the 84th day.

Keywords:

Foam tray, Starch, Polycaprolactone, Polylactic Acid, Polymethyl methacrylate,

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