School of Food Science and Bioengineering, Xihua University, Chengdu, Sichuan Province 610039, China; Chongqing Key Laboratory of Specialty Food Co-Built by Sichuan and Chongqing, Chongqing 400715, China.
School of Food Science and Bioengineering, Xihua University, Chengdu, Sichuan Province 610039, China; Chongqing Key Laboratory of Specialty Food Co-Built by Sichuan and Chongqing, Chongqing 400715, China.
Food Res Int. 2024 Dec;197(Pt 1):115258. doi: 10.1016/j.foodres.2024.115258. Epub 2024 Oct 28.
While heat treatment is a conventional method for the gelation of alkaline-extracted walnut protein isolates (AWPI), it can limit the incorporation of heat-sensitive ingredients. This study explored a novel approach to fabricate cold-set gels from epigallocatechin-3-gallate (EGCG) conjugated AWPI (AWPI-EGCG). EGCG conjugation effectively inhibited the thermal gelation of AWPI while promoting the formation of soluble aggregates upon heat treatment. AWPI-EGCG cold-set gels were then successfully fabricated through acidification with glucono-δ-lactone (GDL). The rheological study revealed that the storage modulus and yield stress of the cold-set gels were positively correlated with the GDL concentration and the EGCG conjugation degree. However, higher concentrations of GDL were associated with the reduced yield strain of the gels. Texture analysis indicated an increase in gel hardness with increasing GDL concentration, accompanied by a decrease in springiness. Microstructural examination by scanning electron microscopy revealed that the AWPI-EGCG cold-set gels with 0.3 % GDL exhibited smaller pores with thinner and smoother internal walls, while those with 0.9 % GDL exhibited relatively larger pores with thicker and denser walls. In addition, the AWPI-EGCG cold-set gels showed promising quercetin encapsulation capacities and controlled release properties.
虽然热处理是碱提核桃蛋白分离物（AWPI）胶凝的常规方法，但它会限制对热敏成分的掺入。本研究探索了一种从表没食子儿茶素没食子酸酯（EGCG）共轭 AWPI（AWPI-EGCG）制备冷胶的新方法。EGCG 共轭有效地抑制了 AWPI 的热凝胶化，同时促进了热处理时可溶性聚集体的形成。然后通过用葡萄糖酸-δ-内酯（GDL）酸化成功制备了 AWPI-EGCG 冷胶。流变学研究表明，冷胶的储能模量和屈服应力与 GDL 浓度和 EGCG 共轭度呈正相关。然而，更高浓度的 GDL 与凝胶的屈服应变降低有关。质构分析表明，随着 GDL 浓度的增加，凝胶硬度增加，弹性降低。扫描电子显微镜的微观结构分析表明，含有 0.3%GDL 的 AWPI-EGCG 冷胶具有较小的孔，内部壁较薄且较光滑，而含有 0.9%GDL 的冷胶具有相对较大的孔，壁较厚且较密集。此外，AWPI-EGCG 冷胶表现出良好的槲皮素包封能力和控制释放性能。
