Izdelava bio osnovanih embalaž za sadje

Ružič, Tina (author), Vrabič Brodnjak, Urška (mentor)

Namen magistrskega dela je bil pokazati uporabnost in obstojnost bio osnovanih materialov,in sicer bakterijske nanoceluloze in natrijevega alginata, za izdelavo embalaže (folije in lončki)za pakiranje sadja – borovnic. Izdelani sta bili dve različici folije na osnovi natrijevega alginata, ena z dodatkom bakterijske nanoceluloze in ena brez. Iz istih mešanic je bil izveden poskus izdelave lončkov, ki ni uspel zaradi nezmožnosti izhlapevanja vode in je bil opuščen zaradi neuspešnega iskanja primernejših kalupov. Folije so bile naprej analizirane (debelina, poroznost, hrapavost, utržna jakost in test propustnosti vodne pare), kasneje pa so bile za obdobje štirih tednov vanje zapakirane borovnice in hranjene v hladilniku. Stanje borovnic je bilo dokumentirano vsak teden, prav tako so bile zabeležene tudi opazne spremembe. Folija iz natrijevega alginata je bila na obeh straneh gladka in prosojna, medtem ko je bila folija iz natrijevega alginata, z dodatkom bakterijske nanoceluloze (BNC), na spodnji strani gladka, na zgornji strani pa hrapava ter je imela rumenkast podton in bila manj prosojna. Rezultati meritev poroznosti obeh izdelanih folij so bili odlični, saj je bilo pri vseh, razen pri eni meritvi, zaznano ničelno prehajanje zraka, kar pomeni da sta obe foliji dobro tesnili. Debelina obeh folij je bila dokaj neenakomerna in je vplivala na mehanske lastnosti folije, v našem primeru na utržno jakost. Hrapavost folije je vplivala na varjenje stranic pri pakiranju – hrapava stran folije se ni zavarila, gladka se je zavarila brez težav. Folija iz natrijevega alginata je pri testiranju obstojnosti borovnic dosegla najboljše rezultate, saj so borovnice brez vidnih sprememb ostale v zelo dobrem stanju 3 tedne, nato se je začel proces sušenja in izgube volumna. Spoji so do konca dobro tesnili, opaziti ni bilo plesni, kondenza ali kakršnih koli drugih sprememb na foliji. Tudi pri borovnicah, zapakiranih v folijo iz natrijevega alginata in BNC-ja, ni bilo vidnih sprememb, vendar so se borovnice precej izsušile.

• Language: Slovenian
• Keywords: natrijev alginat, bakterijska nanoceluloza, folija, biopolimeri, obstojnost
• Work type: Master's thesis/paper
• Organization: NTF - Faculty of Natural Sciences and Engineering
• Year: 2025
• PID: 20.500.12556/RUL-170163
• Publication date in RUL: 02.07.2025

Secondary language

• Language: English
• Title: Production of bio based fruit packaging

Abstract

The aim of the master's thesis was to demonstrate the applicability and durability of bio-based materials, namely bacterial nanocellulose and sodium alginate, for the production of packaging (films and containers) for fruit packaging - blueberries. Two versions of sodium alginate-based films were produced, one with and one without the addition of bacterial nanocellulose. An attempt was made to produce containers from the same mixtures, which failed due to the inability of the water to evaporate and was abandoned due to the failure to find more suitable moulds. The films were further analysed (thickness, porosity, roughness, tensile strength and water vapour permeability test) and then the blueberries were packed in them and stored in a refrigerator for a period of four weeks. The condition of the blueberries was documented on a weekly basis and changes were also noted. The film made of Sodium Alginate was smooth and translucent on both sides, while the one with the addition of bacterial nanocellulose (BNC) was smooth on the underside and rough on the upper side, with a yellowish undertone and less translucent. The results of the porosity measurements of both films were excellent, with all but one measurement showing zero air leakage, meaning that both films have no air permeability. The thickness of the two films was quite uneven and affected the mechanical properties of the film, in this case, the tensile strength. The roughness of the foil affected the welding of the joints during packaging - the rough side of the foil could not be welded, the smooth side welded without problems. The sodium alginate film gave the best results in the blueberry shelf-life test, as the blueberries remained in very good condition for three weeks without any visible changes, after which the drying process and loss of volume started. The joints sealed well until the end, and there was no mold, condensation or any other changes to the foil. The blueberries packed in the film which BNC was added to also showed no visible changes, but the blueberries dried out considerably.

• Keywords: sodium alginate, bacterial nanocellulose, film, biopolymer, durability