Purdue University, Department of Food Science, West Lafayette, IN, USA; Whistler Center for Carbohydrate Research, West Lafayette, IN, USA.
Purdue University, Department of Food Science, West Lafayette, IN, USA.
J Colloid Interface Sci. 2017 Nov 1;505:736-744. doi: 10.1016/j.jcis.2017.06.061. Epub 2017 Jun 23.
Microgels assembled from the protein β-lactoglobulin are colloidal structures with potential applications in food materials. Modifying the internal crosslinking within these microgels using enzymatic or chemical treatments should affect dissolution, swelling, and viscous attributes under strongly solvating conditions.
Microgels were treated with citric acid, glutaraldehyde and transglutaminase to induce cross-linking or with tris(2-carboxyethyl)phosphine to reduce disulfide linkages. Change in hydrodynamic particle size due to acidic pH, alkaline pH, ionic strength, osmolyte concentration, ethanol, urea, sodium dodecyl sulfate, and reducing agents was evaluated by light scattering measurements. Changes in microgel nanomechanical properties were evaluated via force spectroscopic measurements in water.
Average microgel size increased ∼20% in alkaline pH and with ethanol contents above 10%, and decreased ∼20% with sucrose contents above 10%. Cross-linking by glutaraldehyde and transglutaminase prevented size increases in alkaline pH. Microgel plasticity and elastic modulus were unaffected by treatments. Microgels treated with glutaraldehyde were found to have much greater stability to urea, sodium dodecyl sulfate, and reducing agents when compared to other samples. Even without cross-linking, microgels remained stable against precipitation and dissolution over a wide range conditions, indicating their broad utility as colloidal stabilizers, texture modifiers or controlled release agents in food or other applications.
由β-乳球蛋白组成的微凝胶是具有潜在应用于食品材料的胶体结构。使用酶或化学处理对内部分交联进行修饰，应会影响在强溶剂化条件下的溶解、溶胀和粘性特性。
使用柠檬酸、戊二醛和转谷氨酰胺酶处理微凝胶以诱导交联，或使用三（2-羧乙基）膦还原二硫键。通过光散射测量评估由于酸性 pH、碱性 pH、离子强度、渗透压剂浓度、乙醇、尿素、十二烷基硫酸钠和还原剂引起的水动力颗粒尺寸的变化。通过在水中进行力谱测量评估微凝胶纳米力学性能的变化。
在碱性 pH 下和乙醇含量高于 10%时，平均微凝胶尺寸增加了约 20%，而在蔗糖含量高于 10%时，尺寸减小了约 20%。戊二醛和转谷氨酰胺酶交联可防止碱性 pH 下的尺寸增加。处理对微凝胶的塑性和弹性模量没有影响。与其他样品相比，用戊二醛处理的微凝胶发现对尿素、十二烷基硫酸钠和还原剂具有更高的稳定性。即使没有交联，微凝胶在广泛的条件下仍能保持稳定，不会沉淀和溶解，这表明它们在食品或其他应用中作为胶体稳定剂、质地改良剂或控制释放剂具有广泛的用途。
