Learning Institute, King Mongkut's University of Technology Thonburi, Bangkok, 10140, Thailand.
Cellulose and Bio-Based Nanomaterials Research Group, King Mongkut's University of Technology Thonburi, Bangkok, 10140, Thailand.
Sci Rep. 2023 Aug 14;13(1):13195. doi: 10.1038/s41598-023-39739-6.
The widespread usage of petroleum-based polymers as single-use packaging has had harmful effects on the environment. Herein, we developed sustainable chitin nanofiber (ChNF) coatings that prolong the shelf life of fresh cucumbers and delay the growth of pathogenic bacteria on their surfaces. ChNFs with varying degrees of acetylation were successfully prepared via deacetylation using NaOH with treatment times of 0-480 min and defibrillated using mechanical blending. With longer deacetylation reaction times, more acetamido groups (-NHCOCH) in chitin molecules were converted to amino groups (-NH), which imparted antibacterial properties to the ChNFs. The ChNF morphologies were affected by deacetylation reaction time. ChNFs deacetylated for 240 min had an average width of 9.0 nm and lengths of up to several μm, whereas rod-like structured ChNFs with a mean width of 7.3 nm and an average length of 222.3 nm were obtained with the reaction time of 480 min. Furthermore, we demonstrated a standalone ChNF coating to extend the shelf life of cucumbers. In comparison to the rod-like structured ChNFs, the 120 and 240-min deacetylated ChNFs exhibited a fibril-like structure, which considerably retarded the moisture loss of cucumbers and the growth rate of bacteria on their outer surfaces during storage. Cucumbers coated with these 120 and 240-min deacetylated ChNFs demonstrated a lower weight loss rate of ⁓ 3.9% day compared to the uncoated cucumbers, which exhibited a weight loss rate of 4.6% day. This protective effect provided by these renewable ChNFs holds promising potential to reduce food waste and the use of petroleum-based packaging materials.
作为一次性包装的石油基聚合物的广泛使用对环境造成了有害影响。在此，我们开发了可持续的壳聚糖纳米纤维（ChNF）涂层，可延长新鲜黄瓜的保质期并延缓其表面上致病菌的生长。通过使用 NaOH 在 0-480 分钟的处理时间进行脱乙酰化，成功制备了具有不同乙酰化程度的 ChNF，并通过机械共混进行了纤维细化。随着脱乙酰化反应时间的延长，壳聚糖分子中的更多乙酰氨基（-NHCOCH）转化为氨基（-NH），从而赋予 ChNF 抗菌性能。ChNF 的形态受脱乙酰化反应时间的影响。脱乙酰化 240 分钟的 ChNF 的平均宽度为 9.0nm，长度可达数 μm，而在反应时间为 480 分钟时，得到的是具有 7.3nm 平均宽度和 222.3nm 平均长度的棒状结构的 ChNF。此外，我们展示了一种独立的 ChNF 涂层，可延长黄瓜的保质期。与棒状结构的 ChNF 相比，120 和 240 分钟脱乙酰化的 ChNF 表现出纤维状结构，这大大减缓了黄瓜的水分流失和储存过程中其外表面上细菌的生长速度。与未涂层的黄瓜相比，用这些 120 和 240 分钟脱乙酰化的 ChNF 涂层处理的黄瓜的重量损失率较低，约为 3.9%/天，而未涂层的黄瓜的重量损失率为 4.6%/天。这些可再生 ChNF 提供的这种保护作用具有减少食物浪费和减少石油基包装材料使用的巨大潜力。
