State Key Laboratory of Food Science & Technology, School of Food Science & Technology, Jiangnan University, Wuxi, Jiangsu 214122, China.
Department of Food Science, Cornell University, Ithaca, NY 14850, USA.
Food Funct. 2017 Aug 1;8(8):2897-2904. doi: 10.1039/c7fo00570a. Epub 2017 Jul 25.
High-protein intermediate moisture food (HPIMF) containing sodium caseinate (NaCN) often gave a harder texture compared with that made from whey proteins or soy proteins, due to the aggregation of protein particles. The objectives of this study were to explore whether the addition of hydrocolloids could soften the texture and illustrate the possible mechanism. Three kinds of hydrocolloids, xanthan gum, κ-carrageenan, and gum arabic were chosen, and samples including of these three kinds of hydrocolloids were studied through texture analysis using a TPA test and microstructure observation by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). The texture analysis results showed that xanthan gum was more effective at softening the HPIMF containing NaCN compared to κ-carrageenan and gum arabic. In addition, with the increase of xanthan gum concentration from 0.2 to 2%, the HPIMF matrix became softer, and fractures were observed during the compression for samples with xanthan gum added at low concentrations but not 2%. Microstructure observation suggested that the matrix originally dominated by the network formed through the aggregation of swollen protein particles was inhibited by the addition of xanthan gum, resulting in the softening of the texture and also contributing to the fracture during compression. With the increase of xanthan gum concentration up to 2%, the protein dominating network would be gradually replaced with a matrix dominated by the newly formed network of xanthan gum with protein particles as fillers. Furthermore, this formation of a xanthan gum dominating network structure also resulted in changes in small molecule distribution, as observed using low-field NMR.
高蛋白质中间水分食品（HPIMF）含有酪蛋白酸钠（NaCN）时，与乳清蛋白或大豆蛋白相比，由于蛋白质颗粒的聚集，质地通常更硬。本研究的目的是探索添加水胶体是否可以使质地变软，并阐明可能的机制。选择了三种水胶体：黄原胶、κ-卡拉胶和阿拉伯胶，并通过质构分析（TPA 测试）和共聚焦激光扫描显微镜（CLSM）和扫描电子显微镜（SEM）观察微观结构来研究这些三种水胶体的样品。质构分析结果表明，与κ-卡拉胶和阿拉伯胶相比，黄原胶更有效地使含有 NaCN 的 HPIMF 质地变软。此外，随着黄原胶浓度从 0.2%增加到 2%，HPIMF 基质变得更软，并且在添加低浓度黄原胶的样品中观察到压缩过程中的断裂，但在添加 2%黄原胶的样品中没有观察到。微观结构观察表明，原本由膨胀的蛋白质颗粒聚集形成的网络主导的基质，由于添加了黄原胶而受到抑制，从而使质地变软，并且在压缩过程中导致断裂。随着黄原胶浓度的增加至 2%，以蛋白质为主导的网络将逐渐被以新形成的黄原胶网络为主导的基质所取代，其中蛋白质颗粒作为填充物。此外，这种黄原胶主导的网络结构的形成也导致了小分子分布的变化，如低场 NMR 观察到的那样。
