Iron deficiency is a major global human health concern. Encapsulation of iron in functional food products may help to solve this problem. However, iron is highly reactive and may promote rapid lipid oxidation in fatty foods. In this study, the effect of ferrous sulfate (0.1 to 0.5 wt%) and rice bran stearin (0 or 30 wt%) on the physical properties, oxidative stability, and encapsulation efficiency of 20 wt% water-in-oil (W/O) emulsions stabilized with polyglycerol polyricinoleate was investigated. In the presence of rice bran stearin crystals in the continuous oil phase, W/O emulsions had smaller mean droplet diameters (d ∼ 250 nm) and better physical stability than its absence (d ∼ 330 nm). An increase in the ferrous sulfate concentration in the water droplets led to a decrease in the oxidative stability of the W/O emulsions. However, the presence of rice bran stearin significantly (P ≤ 0.05) improved their oxidative stability. Moreover, addition of rice bran stearin also significantly (P ≤ 0.05) improved the encapsulation efficiency and delayed ferrous sulfate release from the W/O emulsions. The impact of pH and ionic strength on the encapsulation efficiency of the W/O emulsion was also investigated. Ionic strength affected the encapsulation efficiency much more than pH. The W/O emulsions created in the present study may be useful for the encapsulation and delivery of iron and other water-soluble nutrients into food products. PRACTICAL APPLICATION Water-in-oil (W/O) emulsions may be used to encapsulate, protect, and deliver water-soluble bioactive compounds or nutrients into food products. In this study, W/O emulsions stabilized using an oil-soluble surfactant (polyglycerol polyricinoleate, PGPR) and fat crystal network (rice bran stearin) were shown to be useful for encapsulation and delivery of iron into foods. This strategy may be a promising approach to reduce iron deficiency, a major nutritional deficiency for people with inadequate food supplies.

中文翻译：

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油包水乳液中的铁包封：硫酸亚铁浓度和脂肪晶体形成对氧化稳定性的影响

缺铁是一个主要的全球人类健康问题。在功能性食品中包裹铁可能有助于解决这个问题。然而，铁具有高反应性，可能会促进脂肪食物中的快速脂质氧化。在本研究中，硫酸亚铁（0.1 至 0.5 wt%）和米糠硬脂（0 或 30 wt%）对 20 wt% 油包水（W/ O) 研究了用聚甘油聚蓖麻油酸酯稳定的乳液。在连续油相中存在米糠硬脂晶体的情况下，W/O 乳液具有更小的平均液滴直径（d ~ 250 nm）和比不存在时更好的物理稳定性（d ~ 330 nm）。水滴中硫酸亚铁浓度的增加导致 W/O 乳液的氧化稳定性降低。然而，米糠硬脂的存在显着（P≤0.05）提高了它们的氧化稳定性。此外，添加米糠硬脂也显着（P ≤ 0.05）提高了包封效率并延迟了 W/O 乳液中硫酸亚铁的释放。还研究了 pH 值和离子强度对 W/O 乳液包封效率的影响。离子强度对封装效率的影响远大于 pH。本研究中产生的 W/O 乳液可能有助于将铁和其他水溶性营养物质包裹和输送到食品中。实际应用 油包水 (W/O) 乳液可用于封装、保护水溶性生物活性化合物或营养素并将其输送到食品中。在这项研究中，使用油溶性表面活性剂（聚蓖麻油酸甘油酯，PGPR）和脂肪晶体网络（米糠硬脂）稳定的 W/O 乳液被证明可用于将铁包封和输送到食物中。这种策略可能是减少缺铁的一种有前途的方法，缺铁是食物供应不足的人的主要营养缺乏症。