以靜電紡絲技術包埋檸檬烯於β環狀糊精及聚乙烯醇奈米纖維之新穎活性包材開發

Electrospinning Encapsulation of D-limonene into Nanofiber of β-cyclodextrin and Polyvinyl Alcohol for Developing a Novel Active Packaging Material

蘇昱穎(Yu-Ying Su)

指導教授 ： 丁俞文

國立臺灣大學/生物資源暨農學院/食品科技研究所/碩士(2019年)

https://doi.org/10.6342/NTU201901619

摘要

抗菌包裝能減緩食品腐敗以延長貨架期及減少食品中毒風險，將奈米技術應用於抗菌包材可提高成品機械強度，並提升單位體積下反應表面積，使活性物質作用效果更迅速。靜電紡絲是一種新興生產奈米纖維之技術，生產程序簡單且為非熱加工，有效提升活性物質之包覆效率，從而增加其適用性。植物合成之精油，因有許多正面功效而被廣泛運用於製藥及食品領域，D-檸檬烯是柑橘精油主成分，具抗菌，抗氧化和抗癌活性，然而，檸檬烯的使用受其本身高度揮發性而受限制，且暴露於空氣後會迅速氧化。因此，運用具減緩物質揮發性及氧化性之β-環狀糊精（βCD）以改善，βCD具前述優點是因其可將疏水性化合物包埋到內腔。
本研究以βCD作為包覆檸檬烯的核心材料，聚乙烯醇（PVA）用於形成纖維基質。為了生產具有最佳性能的纖維，研究了包括電壓，流速，收集距離在內的操作參數。掃描電子顯微鏡（SEM）用於研究形態和直徑。熱重分析（TGA）用於檢測熱穩定性。ISO 20743評估薄膜對大腸桿菌及金黃色葡萄球菌之抗菌能力。X-光繞射儀（XRD）用於觀測βCD是否為有效包埋活性物質的通道型。最後，使用氣相層析火焰離子化偵檢器（GC-FID）分析承載效率。在SEM觀察中，優化纖維的表面是光滑且其直徑約180 nm，這表明大的表面積與體積比。於TGA結果，游離檸檬烯於環境溫度下開始釋放並在160℃釋放完畢，而固定在PVA膜內的檸檬烯/βCD複合物則顯示116°C~180°C都有檸檬烯質量損失，這表明包埋後檸檬烯熱穩定性顯著增加。XRD結果確認成品中的βCD為有效包埋物質的通道型。檸檬烯承載效率約為93％。 PVA /檸檬烯/βCD 奈米薄膜對大腸桿菌及金黃色葡萄球菌的抗菌能力為95.23%及97.84%。總結，新開發的PVA/檸檬烯/βCD 具有高的承載效率、穩定性及抗菌活性，具有應用於食品包裝和生物醫學領域的潛力。

關鍵字

靜電紡絲 ； β環狀糊精 ； R-（+）-檸檬烯 ； 聚乙烯醇 ； 抗菌包裝

並列摘要

Active packaging used to eliminate food born spoilage has been a promising investigation in the field of food packaging. D-limonene, a main component of citrus essential oil, was reported to have antimicrobial, antioxidant and anticarcinogenic Activity. However, the use of limonene is constrained due to their highly volatile nature and would be rapidly oxidized when exposed to air. Hence, β-cyclodextrin with ability of entrapping hydrophobic compound into its inner cavity was used to improve aqueous solubility and stability of essential oil. Recently, nanotechnology that is capable of improving mechanical strength and exhibiting a larger surface to volume ratio has been applied to upgrade efficacy of active packaging system. Among various approaches to produce nanomaterials, electrospinning is an emerging technique with simple operating process and high encapsulation efficiency could be used to fix substances into fiber mat increasing its applicability. In this work, β-cyclodextrin(βCD) was used as core material to encapsulate limonene. Additionally, 8 wt% polyvinyl alcohol(PVA) was used to form fiber matrix. To produce fiber mat with optimum properties, operation parameter including voltage, flow speed, collection distance was researched. Scanning electron microscopy(SEM) was used to study morphology and diameter. Thermogravimetric analysis(TGA) was used to detect the thermal stability. The crystalline structure of fiber mat was recorded by X-Ray powder Diffraction(XRD). Antibacterial ability was accessed by ISO 20743 against E. coli and S.aureus. Finally, the loading efficiency were analyzed using gas chromatography - flame ionization detector(GC-FID). In SEM observation, the surface of the optimized fiber was smooth and its diameter was around 180 nm indicating a large surface area to volume ratio. From the TGA result, it shows release of free-form limonene started at ambient temperature and reached its maximum rate at 160°C, whereas limonene/β-CD complexes fixed within the PVA membrane show limonene mass lost at 116°C~180°C. This phenomenon indicated a significant increase of limonene stability after being encapsulated. Through XRD result, the present of inclusion between βCD and limonene can be confirmed. The loading efficiency of limonene was around 93%. PVA/ limonene/βCD nanaofibers exhibited 97.84% and 95.23% antibacterial ability against S.aureus and E.coli. In conclusion, newly developed PVA/ limonene/βCD with high loading efficiency, antibacterial activity may have great potentials for applications in food packaging and biomedical field.

並列關鍵字

electrospinning ； β-cyclodextrin ； R-(+)-limonene ； active packaging ； antibacterial food packaging

參考文獻

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