Department of Biotechnology and Food Science, Durban University of Technology, P.O. Box 1334, Durban 4000, South Africa.
Department of Biotechnology and Food Science, Durban University of Technology, P.O. Box 1334, Durban 4000, South Africa.
Food Res Int. 2023 Jan;163:112171. doi: 10.1016/j.foodres.2022.112171. Epub 2022 Nov 19.
Enzymatic crosslinking has gained attention in improving plant protein heat-induced gels, which are composed of weak network structures. The aim of the study was to investigate the effect of laccase crosslinking on the rheological and microstructural properties of heat-induced Bambara groundnut protein gels. The rheological properties of laccase-modified Bambara groundnut protein isolate (BPI) gel formed in situ were investigated. Changes in viscoelastic properties were monitored during heating and cooling ramps and gel structure fingerprints were analyzed by frequency sweep. Laccase addition induced an initial protein structure breakdown (G″>G') at an enzyme dose-dependent (1-3 U/g) before gel formation and stabilization. Gel point temperatures were significantly decreased from 85°C to 29°C (∼3 folds) with increasing laccase activity (0 to 3 U/g protein, respectively). For laccase crosslinked gels, G' was substantially greater than G" (>1 log) with no dependency on angular frequency, which suggests the formation of relatively well-structured gels. The highest gel strength (tan δ of 0.09, G* of 555.51 kPa & An of 468.04 kPa) was recorded at a laccase activity of 2 U/g protein and the gels formed at this activity appeared homogeneous with compact lath sheet-like structure. The crosslinking effects of laccase were corroborated by the decrease in thiol and phenolic contents as well as the crosslinking of amino acids in model reactions. Overall, the use of laccase improved gel properties and significantly altered the gelation profile of BPI. Laccase-modified Bambara groundnut protein gels have potential to be used in food texture improvement and development of new food products. For instance, they can be used in plant-based milk products such as yoghurt and cheese.
酶交联在改善植物蛋白热诱导凝胶方面引起了关注，这些凝胶由弱网络结构组成。本研究旨在研究漆酶交联对热诱导斑豆蛋白凝胶的流变学和微观结构特性的影响。研究了原位形成的漆酶改性斑豆蛋白分离物（BPI）凝胶的流变学性质。在加热和冷却斜坡过程中监测了粘弹性性质的变化，并通过频率扫描分析了凝胶结构指纹。在酶剂量依赖性（1-3 U/g）的情况下，漆酶的添加会导致初始蛋白质结构的破坏（G″>G'），然后再形成凝胶并稳定下来。随着漆酶活性（分别为 0 至 3 U/g 蛋白）的增加，凝胶点温度从 85°C 显著降低至 29°C（约 3 倍）。对于漆酶交联的凝胶，G'明显大于 G"（>1 对数），与角频率无关，这表明形成了相对结构良好的凝胶。在漆酶活性为 2 U/g 蛋白时，记录到最高的凝胶强度（tan δ为 0.09，G*为 555.51 kPa 和 An 为 468.04 kPa），并且在该活性下形成的凝胶看起来均匀，具有紧凑的薄片状结构。漆酶的交联效应通过模型反应中巯基和酚类含量的减少以及氨基酸的交联得到了证实。总体而言，漆酶的使用改善了凝胶性能，并显著改变了 BPI 的胶凝特性。漆酶改性斑豆蛋白凝胶具有改善食品质地和开发新型食品产品的潜力。例如，它们可用于植物性乳制品，如酸奶和奶酪。
