A promising natural blue colorant was obtained from the cross-linking between genipin and milk proteins. Milk was simultaneously used to extract genipin from the unripe genipap (Genipa americana L.) and evaluated as a reaction medium and carrier for the novel blue colorant. The effects of the milk composition (skimmed, semi-skimmed, and whole) on the kinetic of blue color formation in the colorant-loaded milk samples during their cold storage time for 96 h were evaluated using their color parameters and free-genipin content. The reaction between milk proteins and genipin were evaluated by FTIR spectroscopy. In addition, the blue colorant-loaded milk samples were characterized according to their droplet size distribution, microstructure, and phase separation kinetics. The milk fat content influenced the genipin recovery while the milk with higher protein content contributed to obtaining a more intense blue color. Using whole milk with 3.0 g/100 g fat content favored the light scattering and, thus, a blue colorant with a more intense −b^∗ and L^∗ values was obtained. On the other hand, the use of skimmed milk with 0.5 g/100 g fat content resulted in more consumption of genipin due to its more protein content for the reaction of blue color compounds formation. Thus, a more intense and darker blue coloration was observed with lower light scattering. The milk composition did not modify the phase separation kinetics of the blue colorant-loaded milk. Therefore, our results have demonstrated that the milk was a suitable medium for the reaction of blue color formation and also a good blue compounds carrier.

Industrial relevance

Consumer demands for natural colorants have increased in the last years.

Thus, the new food industry challenge is to develop novel healthy, safe and high-quality food products based on natural colorants. Currently, the colorant market does not have still available a natural blue colorant. Therefore, the development of a novel natural blue colorant from plant material could meet this worldwide demand increasing the added value of many products such as ice cream, dairy beverages, and candies.

中文翻译：

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乳胶体系统作为反应介质和天然染料的天然载体，是通过京尼平与乳蛋白之间的交联而获得的

从genipin和牛奶蛋白之间的交联获得了一种有希望的天然蓝色着色剂。同时使用牛奶从未成熟的genipap（美国GenipaL.），并作为新型蓝色着色剂的反应介质和载体进行了评估。使用牛奶的颜色参数和游离京尼平含量，评估了牛奶成分（脱脂，半脱脂和全脂）对着色剂加载的牛奶样品在冷藏96小时后蓝色形成动力学的影响。牛奶蛋白和京尼平之间的反应通过FTIR光谱进行了评估。此外，根据蓝色液滴负载的牛奶样品的液滴尺寸分布，微结构和相分离动力学对其进行了表征。牛奶中的脂肪含量影响了Genipin的回收率，而蛋白质含量较高的牛奶则有助于获得更深的蓝色。使用脂肪含量为3.0 g / 100 g的全脂牛奶有利于光散射，因此，蓝色着色剂的色泽更浓-获得b ^＊和L ^＊值。另一方面，使用脂肪含量为0.5 g / 100 g的脱脂牛奶会导致Genipin的消耗量增加，这是因为其含有更多的蛋白质，用于形成蓝色化合物。因此，在较低的光散射下观察到更强烈和更深的蓝色。牛奶组合物未改变装载蓝色着色剂的牛奶的相分离动力学。因此，我们的结果表明，牛奶是形成蓝色反应的合适介质，也是良好的蓝色化合物载体。

行业相关性

近年来，消费者对天然着色剂的需求增加了。

因此，食品工业的新挑战是开发基于天然着色剂的新型健康，安全和优质食品。当前，着色剂市场上还没有天然蓝色着色剂。因此，由植物材料开发出一种新颖的天然蓝色着色剂可以满足世界范围的需求，从而提高许多产品（如冰淇淋，乳制饮料和糖果）的附加值。