Kowalonek Jolanta, Łukomska Bogna, Szydłowska-Czerniak Aleksandra
Department of Biomedical and Polymer Chemistry, Faculty of Chemistry, Nicolaus Copernicus University in Toruń, Gagarina 7, 87-100 Toruń, Poland.
Department of Analytical Chemistry and Applied Spectroscopy, Faculty of Chemistry, Nicolaus Copernicus University in Toruń, Gagarina 7, 87-100 Toruń, Poland.
Molecules. 2025 Jan 9;30(2):245. doi: 10.3390/molecules30020245.
In this study, biodegradable and active films based on sodium alginate incorporated with different concentrations of oils (25% and 50%) from fruit seeds were developed for potential applications in food packaging. The ultraviolet and visible (UV-VIS) spectra of raspberry seed oil (RSO) and black currant seed oil (BCSO) indicated differences in bioactive compounds, such as tocopherols, phenolic compounds, carotenoids, chlorophyll, and oxidative status (amounts of dienes, trienes, and tetraenes) of active components added to alginate films. The study encompassed the color, structure, and thermal stability analysis of sodium alginate films incorporated with RSO and BCSO and their mixtures. The color of alginate films before and after the addition of oils from both fruit seeds was evaluated by measuring color coordinates in the CIELab color space: L* (lightness), a* (red-green), and b* (yellow-blue). The lightness values ranged between 94.21 and 95.08, and the redness values varied from -2.20 to -2.65, slightly decreasing for the films enriched with oils. In contrast, yellowness values ranged between 2.93 and 5.80 for the obtained active materials, significantly increasing compared to the control alginate film (L* = 95.48, a* = -1.92, and b* = -0.14). Changes in the structure and morphology of the alginate films after incorporating bioactive-rich oils were observed using scanning electron microscopy (SEM). Films with RSO and oil mixtures had more developed surfaces than films with BCSO. Moreover, the cross-sections of the films with RSO showed holes evenly distributed inside the films, indicating traces of volatile compounds. Thermal decomposition of the alginate films loaded with oils showed five separate stages (to 125 °C, 125-300 °C, 310-410 °C, 410-510 °C, and 750-1000 °C, respectively) related to the oil and surfactant decomposition. The shape of the thermogravimetric curves did not depend on the oil type. The added oils reduced the efficiency of alginate decomposition in the first stage. The obtained results showed that new functional and thermally stable food packaging films based on sodium alginate with a visual appearance acceptable to consumers could be produced by utilizing oils from fruit seed residues.
在本研究中，开发了基于海藻酸钠并掺入不同浓度（25%和50%）水果籽精油的可生物降解活性薄膜，用于食品包装的潜在应用。树莓籽油（RSO）和黑加仑籽油（BCSO）的紫外可见（UV-VIS）光谱表明，添加到海藻酸盐薄膜中的生物活性化合物存在差异，如生育酚、酚类化合物、类胡萝卜素、叶绿素以及活性成分的氧化状态（二烯、三烯和四烯的含量）。该研究包括对掺入RSO和BCSO及其混合物的海藻酸钠薄膜的颜色、结构和热稳定性分析。通过在CIELab颜色空间中测量颜色坐标：L*（明度）、a*（红-绿）和b*（黄-蓝），评估添加两种水果籽精油前后海藻酸盐薄膜的颜色。明度值在94.21至95.08之间，红色度值在-2.20至-2.65之间，富含精油的薄膜略有下降。相比之下，所得活性材料的黄色度值在2.93至5.80之间，与对照海藻酸盐薄膜（L* = 95.48，a* = -1.92，b* = -0.14）相比显著增加。使用扫描电子显微镜（SEM）观察掺入富含生物活性精油后海藻酸盐薄膜的结构和形态变化。含有RSO和油混合物的薄膜比含有BCSO的薄膜具有更发达的表面。此外，含有RSO的薄膜横截面显示薄膜内部有均匀分布的孔洞，表明有挥发性化合物的痕迹。负载精油的海藻酸盐薄膜的热分解显示出五个不同阶段（分别至125℃、125 - 300℃、310 - 410℃、410 - 510℃和750 - 1000℃），与油和表面活性剂的分解有关。热重曲线的形状不取决于油的类型。添加的油降低了海藻酸盐在第一阶段的分解效率。所得结果表明，利用水果籽残渣中的油可以生产出基于海藻酸钠的新型功能性和热稳定的食品包装薄膜，其外观在消费者可接受范围内。
