BACKGROUND Salted duck egg white (SDEW) is a major by-product during salted egg yolk manufacturing. Due to high salt concentration, SDEW has not been efficiently utilized. Moreover, functional properties of SDEW are altered by salt during pickling. To improve the functional properties, the effect of κ-carrageenan (κ-CAR) addition on the protein structure and gel properties of SDEW was investigated in this study. RESULTS The surface hydrophobicity and free sulfhydryl content of SDEW protein increased, while total sulfhydryl content decreased significantly with the addition of κ-CAR (0.02-0.10%). Fourier transform infrared spectroscopy analysis revealed that the relative content of α-helix and β-turn decreased, β-sheet and random coil increased, indicating the variation tendency of protein structure from order to disorder. As κ-CAR addition increased, the texture profiles including hardness, gumminess, chewiness, springiness, cohesiveness and resilience of SDEW gel were all improved. Water holding capacity increased significantly by 32.33% in the presence of 0.10% κ-CAR addition. The scanning electron microscopy indicated that the microstructure of SDEW/κ-CAR mixed gel was more smooth and compact. CONCLUSION The results suggested that adding κ-CAR can be an effective method to improve gel quality of SDEW. This study is expected to provide theoretical basis for modification of SDEW protein, as well as preparation of food ingredients with better gel properties from SDEW. This article is protected by copyright. All rights reserved.

中文翻译：

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添加κ-角叉菜胶对咸鸭蛋清蛋白质结构和凝胶特性的影响

背景咸鸭蛋清(SDEW)是咸蛋黄制造过程中的主要副产品。由于高盐浓度，SDEW 没有得到有效利用。此外，酸洗过程中盐会改变 SDEW 的功能特性。为了改善功能特性，本研究研究了 κ-角叉菜胶 (κ-CAR) 添加对 SDEW 蛋白质结构和凝胶特性的影响。结果随着κ-CAR（0.02-0.10%）的加入，SDEW蛋白的表面疏水性和游离巯基含量增加，而总巯基含量显着降低。傅里叶变换红外光谱分析表明，α-螺旋和β-转角的相对含量减少，β-折叠和无规卷曲增加，表明蛋白质结构有由有序到无序的变化趋势。随着κ-CAR添加量的增加，SDEW凝胶的质地特征包括硬度、粘性、咀嚼性、弹性、内聚性和回弹性均得到改善。在 0.10% κ-CAR 添加的情况下，持水能力显着提高了 32.33%。扫描电镜表明SDEW/κ-CAR混合凝胶的微观结构更加光滑致密。结论结果表明，添加κ-CAR是提高SDEW凝胶质量的有效方法。该研究有望为SDEW蛋白的修饰以及从SDEW制备具有更好凝胶特性的食品成分提供理论依据。本文受版权保护。版权所有。在 0.10% κ-CAR 添加的情况下，持水能力显着提高了 32.33%。扫描电镜表明SDEW/κ-CAR混合凝胶的微观结构更加光滑致密。结论结果表明，添加κ-CAR是提高SDEW凝胶质量的有效方法。该研究有望为SDEW蛋白的修饰以及从SDEW制备具有更好凝胶特性的食品成分提供理论依据。本文受版权保护。版权所有。在 0.10% κ-CAR 添加的情况下，持水能力显着提高了 32.33%。扫描电镜表明SDEW/κ-CAR混合凝胶的微观结构更加光滑致密。结论结果表明，添加κ-CAR是提高SDEW凝胶质量的有效方法。该研究有望为SDEW蛋白的修饰以及从SDEW制备具有更好凝胶特性的食品成分提供理论依据。本文受版权保护。版权所有。结论结果表明，添加κ-CAR是提高SDEW凝胶质量的有效方法。该研究有望为SDEW蛋白的修饰以及从SDEW制备具有更好凝胶特性的食品成分提供理论依据。本文受版权保护。版权所有。结论结果表明，添加κ-CAR是提高SDEW凝胶质量的有效方法。该研究有望为SDEW蛋白的修饰以及从SDEW制备具有更好凝胶特性的食品成分提供理论依据。本文受版权保护。版权所有。