College of Food Science and Engineering, JiangXi Agricultural University, Nanchang 330045, China.
J Sci Food Agric. 2011 May;91(7):1222-9. doi: 10.1002/jsfa.4303. Epub 2011 Feb 15.
Zein, the predominant protein in corn, has been extensively studied as an alternative packaging material in edible and biodegradable films. However, films made from 100% zein are brittle under normal conditions. The aim of this investigation was to improve the film-forming properties of zein by chemical phosphorylation. The surface hydrophobicity, surface microstructure and mechanical properties of films based on untreated and phosphorus oxychloride (POCl(3))-treated zein were evaluated and compared. The effect of POCl(3) treatment on the rheological properties of zein solutions was also studied.
POCl(3) treatment, especially at pH 7 and 9, led to an increase in the apparent viscosity of zein solutions. Atomic force microscopy (AFM) analysis showed that the film based on POCl(3) -treated zein at pH 7 had a stone-like surface microstructure with a higher roughness (R(q)) than the untreated zein film. The AFM data may partially account for the phenomenon that this film exhibited high surface hydrophobicity (H(0) ). POCl(3) treatment diminished the tensile strength (TS) of zein films from 4.83-6.67 to 1.3-2.29 MPa. However, the elongation at break (EAB) of the films at pH 7 and 9 increased from 3.0-4.5% (control film) to 150.1-122.7% (POCl(3) -treated film), indicating the potential application of zein films in wrapping foods or in non-food industries such as sugar, fruit or troche that need good extension packing materials.
The data presented suggest that the properties of zein films could be modulated by chemical phosphorylation treatment with POCl(3) at an appropriate pH value.
玉米中的主要蛋白质玉米醇溶蛋白已被广泛研究作为可食用和可生物降解薄膜的替代包装材料。然而，在正常条件下，由 100%玉米醇溶蛋白制成的薄膜是脆性的。本研究的目的是通过化学磷酸化来改善玉米醇溶蛋白的成膜性能。评估和比较了未经处理和三氯氧磷（POCl(3)）处理的玉米醇溶蛋白基膜的表面疏水性、表面微观结构和机械性能。还研究了 POCl(3)处理对玉米醇溶蛋白溶液流变性能的影响。
POCl(3)处理，特别是在 pH 值为 7 和 9 时，导致玉米醇溶蛋白溶液的表观粘度增加。原子力显微镜（AFM）分析表明，在 pH 值为 7 的 POCl(3)处理的玉米醇溶蛋白基膜具有石状表面微观结构，其粗糙度（R(q)）高于未经处理的玉米醇溶蛋白膜。AFM 数据可能部分解释了该膜表现出高表面疏水性（H(0)）的现象。POCl(3)处理使玉米醇溶蛋白膜的拉伸强度（TS）从 4.83-6.67 降至 1.3-2.29 MPa。然而，在 pH 值为 7 和 9 的膜的断裂伸长率（EAB）从 3.0-4.5%（对照膜）增加到 150.1-122.7%（POCl(3)处理膜），表明玉米醇溶蛋白膜在包装食品或在非食品行业（如需要良好延伸包装材料的糖、水果或锭剂）中的潜在应用。
所提供的数据表明，玉米醇溶蛋白膜的性能可以通过在适当的 pH 值下用 POCl(3)进行化学磷酸化处理来调节。
