Rheological and Stability Properties of Citrullus Lanatus Mucosospermus, Lanatus Citroides and Moringa Oleifera Seed Hydrocolloids in Oil-in-Water Emulsion

This study investigates the development, characterisation, and functional application of plant-based hydrocolloids extracted from Citrullus lanatus mucosospermus (egusi), Citrullus lanatus citroides (makataan), and Moringa oleifera seeds for use as natural emulsifiers in oil-in-water food systems. The research responds to the global demand for sustainable, clean-label ingredients by exploring underutilised African oilseeds as alternative sources of high-protein hydrocolloids capable of replacing synthetic stabilisers in food formulations.The study involves the extraction of hydrocolloids using an optimised hot-water treatment process followed by detailed compositional, functional, and rheological evaluation. Key analyses include protein and fat quantification, particle size analysis, viscosity behaviour under varying shear conditions, viscoelastic properties, and gelation mechanisms at different concentrations. Emulsion stability trials are conducted to determine droplet size distribution, creaming index, and formulation ratios that yield optimum stability.Findings demonstrate pseudoplastic flow behaviour and distinct structural formation patterns at critical concentration thresholds. Moringa hydrocolloids form weaker elastic gels through hydrophobic interactions, while egusi and makataan develop stronger elastic networks driven by hydrophilic cross-linking. Emulsion optimisation further reveals that hydrocolloid concentrations between 20–30% combined with 37–40% oil and 25–45% water promote the most stable formulations.Overall, the study contributes to food science by providing mechanistic insight into the behaviour of indigenous seed hydrocolloids and validating their potential as sustainable emulsifiers for food product development. The work expands scientific knowledge on under-utilised crops, supports food security objectives, and promotes the valorisation of natural plant resources in clean-label and climate-smart processing systems.

本研究针对从籽用西瓜（Citrullus lanatus mucosospermus，egusi）、刺西瓜（Citrullus lanatus citroides，makataan）以及辣木（Moringa oleifera）种子中提取的植物基亲水胶体（plant-based hydrocolloids）的制备、表征及功能应用展开探究，旨在将其作为天然乳化剂应用于水包油（oil-in-water）食品体系中。本研究响应了全球对可持续清洁标签（clean-label）配料的需求，通过挖掘未充分利用的非洲油料种子，开发可替代食品配方中合成稳定剂的高蛋白亲水胶体替代来源。研究采用优化后的热水提取工艺获取亲水胶体，随后开展全面的成分、功能及流变学表征分析。关键分析内容包括蛋白质与脂肪定量、粒径分布分析、不同剪切条件下的黏度行为、粘弹性特性，以及不同浓度下的凝胶形成机制。此外，本研究开展乳液稳定性试验，以测定液滴粒径分布、乳析指数（creaming index）及可实现最优稳定性的配方比例。研究结果表明，三种亲水胶体均表现出假塑性流变行为（pseudoplastic flow behaviour），且在临界浓度阈值下呈现独特的结构形成模式：辣木亲水胶体通过疏水相互作用（hydrophobic interactions）形成较弱的弹性凝胶，而籽用西瓜与刺西瓜则通过亲水交联（hydrophilic cross-linking）作用形成更强的弹性网络结构。乳液优化试验进一步显示，当亲水胶体浓度处于20%~30%、油脂占比37%~40%、水相占比25%~45%时，可获得最稳定的水包油乳液配方。总体而言，本研究通过揭示本土种子亲水胶体的行为机制，验证了其作为可持续乳化剂用于食品产品开发的潜力，为食品科学领域作出了贡献。本研究拓展了关于未充分利用作物的科学认知，助力粮食安全目标的实现，并推动了清洁标签与气候智能型（climate-smart）加工体系中天然植物资源的增值利用。