PDF(Pubmed)
Abstract：
Edible hydrogel coatings or films in comparison to conventional food packaging materials are characterized as thin layers obtained from biopolymers that can be applied or enveloped onto the surface of food products. The use of lipid-containing hydrogel packaging materials, primarily as edible protective coatings for food applications, is recognized for their excellent barrier capacity against water vapor during storage. With the high brittleness of waxes and the oxidation of different fats or oils, highly stable agents are desirable. Jojoba oil obtained from the jojoba shrub is an ester of long-chain fatty acids and monovalent, long-chain alcohols, which contains natural oxidants α, β, and δ tocopherols; therefore, it is resistant to oxidation and shows high thermal stability. The production of hydrogel films and coatings involves solvent evaporation, which may occur in ambient or controlled drying conditions. The study aimed to determine the effect of drying conditions (temperature from 20 to 70 °C and relative humidity from 30 to 70%) and jojoba oil addition at the concentrations of 0, 0.5, 1.0, 1.5, and 2.0% on the selected physical properties of hydrogel edible films based on whey protein isolate. Homogenization resulted in stable, film-forming emulsions with bimodal lipid droplet distribution and a particle size close to 3 and 45 µm. When higher drying temperatures were used, the drying time was much shorter (minimum 2 h for temperature of 70 °C and relative humidity of 30%) and a more compact structure, lower water content (12.00-13.68%), and better mechanical resistance (3.48-3.93 MPa) of hydrogel whey protein films were observed. The optimal conditions for drying hydrogel whey protein films are a temperature of 50 °C and an air humidity of 30% over 3 h. Increasing the content of jojoba oil caused noticeable color changes (total color difference increased from 2.00 to 2.43 at 20 °C and from 2.58 to 3.04 at 70 °C), improved mechanical elasticity (the highest at 60 °C from 48.4 to 101.1%), and reduced water vapor permeability (the highest at 70 °C from 9.00·10-10 to 6.35·10-10 g/m·s·Pa) of the analyzed films. The observations of scanning electron micrographs showed the heterogeneity of the film surface and irregular distribution of lipid droplets in the film matrix.
摘要：
与常规食品包装材料相比,可食用水凝胶涂层或膜的特征在于由生物聚合物获得的薄层,其可以被施加或包封到食品表面上。使用含脂质的水凝胶包装材料，主要作为食品应用的可食用保护涂层，因其在储存过程中对水蒸气的优异阻隔能力而得到认可。随着蜡的高脆性和不同脂肪或油的氧化，高度稳定的试剂是理想的。从荷荷巴灌木中获得的荷荷巴油是长链脂肪酸和单价的酯，长链醇，其中含有天然氧化剂α，β,和δ生育酚；因此，它是耐氧化和显示高热稳定性。水凝胶薄膜和涂层的生产涉及溶剂蒸发，这可能发生在环境或受控干燥条件。该研究旨在确定干燥条件（温度为20至70°C，相对湿度为30至70％）和添加浓度为0、0.5、1.0、1.5和2.0％的荷荷巴油对所选物理性质的影响基于乳清蛋白分离物的水凝胶可食用膜。均质化导致稳定，具有双峰脂质液滴分布且粒径接近3和45µm的成膜乳液。当使用较高的干燥温度时，干燥时间短得多（温度为70°C，相对湿度为30％时最少2小时），结构更紧凑，含水率较低（12.00-13.68%），并且观察到水凝胶乳清蛋白膜的更好的机械抗性（3.48-3.93MPa）。干燥水凝胶乳清蛋白膜的最佳条件是温度为50°C，空气湿度为30％超过3小时。增加荷荷巴油的含量会引起明显的颜色变化（总色差在20°C时从2.00增加到2.43，在70°C时从2.58增加到3.04），提高了机械弹性（在60°C时最高，从48.4％提高到101.1％），并降低了所分析薄膜的水蒸气渗透率（在70°C时从9.00·10-10至6.35·10-10g/m·s·Pa最高）。扫描电子显微照片的观察显示膜表面的异质性和膜基质中脂质滴的不规则分布。
