Biological and Agricultural Engineering, Louisiana State University Agricultural Center, Baton Rouge, Louisiana 70803, USA.
J Agric Food Chem. 2009 Aug 26;57(16):7505-12. doi: 10.1021/jf900563a.
The increased tendency toward healthy lifestyles has promoted natural food ingredients to the detriment of synthetic components of food products. The trend followed into the colorant arena, with consumers worried about potential health problems associated with synthetic colorants and demanding food products that use natural pigments. The goal of this study was to entrap a lipophilic natural pigment (beta-carotene) in a water-soluble matrix made of Ca(2+) cross-linked alginic acid, to allow its use as a colorant in water-based foods. The effects of different synthesis parameters such as type of solvent, alginic acid concentration, and calcium chloride concentration on nanoparticle characteristics (i.e., size, zeta potential, and morphology) were evaluated. The particle stability was assessed by measuring aggregation against pH, oxidation, and particle precipitation as a function of time. The particle synthesized measured 120-180 nm when formed with chloroform and 500-950 nm when synthesized with ethyl acetate. The particles were negatively charged (-70 to -80 mV zeta potential) and were stable at pH values ranging from 3 to 7. The presence of calcium was prevalent on the particles, indicating that the divalent ions were responsible for cross-linking lecithin with alginic acid and forming the matrix around the beta-carotene pockets. The addition of calcium increased nanoparticle density and improved beta-carotene protection against oxidation. It is concluded that the method proposed herein was capable of forming water-soluble nanoparticles with entrapped beta-carotene of controlled functionality, as a result of the type of solvent and the amounts of alginate and Ca(2+) used.
健康生活方式的日益普及促使天然食品成分逐渐取代了食品产品中的合成成分。这种趋势也在食品着色剂领域得到了体现，消费者担心与合成着色剂相关的潜在健康问题，因此要求使用天然色素的食品。本研究的目的是将亲脂性天然色素（β-胡萝卜素）包埋在由 Ca(2+)交联的海藻酸组成的水溶性基质中，以便将其用作水基食品的着色剂。研究了不同合成参数（如溶剂类型、海藻酸钠浓度和氯化钙浓度）对纳米颗粒特性（如粒径、zeta 电位和形态）的影响。通过测量粒子在不同 pH 值、氧化和沉淀条件下的聚集情况来评估粒子的稳定性。合成的粒子在氯仿中形成时粒径为 120-180nm，在乙酸乙酯中形成时粒径为 500-950nm。粒子带负电荷（-70 至-80mV 的 zeta 电位），在 pH 值为 3 至 7 的范围内稳定。粒子上存在大量的钙，表明二价离子负责将卵磷脂与海藻酸交联，并在β-胡萝卜素口袋周围形成基质。添加钙可以增加纳米粒子的密度，并提高β-胡萝卜素对氧化的保护作用。综上所述，本文提出的方法能够形成具有可控功能的水溶性纳米粒子，这是由于所使用的溶剂类型、海藻酸钠和 Ca(2+)的用量不同所致。
