School of Science, RMIT University, Melbourne, VIC 3083, Australia.
School of Science, RMIT University, Melbourne, VIC 3083, Australia; CSIRO Manufacturing Flagship, Clayton South, VIC 3169, Australia.
Int J Biol Macromol. 2017 Feb;95:985-994. doi: 10.1016/j.ijbiomac.2016.10.087. Epub 2016 Oct 29.
Bovine lactoferrin (LF) powders were produced using spray drying and freeze drying. Industrially obtained fresh liquid-LF was used as starting material. The antioxidant capacity, solubility in water, moisture sorption behaviour, the extent of denaturation and changes in the secondary structural features of spray-dried (SDLF) and freeze-dried bovine lactoferrin (FDLF) powders were determined. The residual moisture content, water activity, particle size and amorphous/crystalline nature of the SDLF and FDLF were also measured. Results showed that both SDLF and FDLF powders had negligible denaturation and conformation changes compared to the liquid-LF. Both SDLF and FDLF showed type II sorption behaviour with almost identical monolayer moisture content. The SDLF powders were amorphous in nature with >98% solubility in water. The antioxidant activity of SDLF was similar to that of the liquid-LF while it was ∼6% less in FDLF. Based on the residual moisture content, water activity, solubility and preservation of secondary structure of LF in resultant powders, a spray drying process with 180°C inlet and 95°C outlet temperature was found to produce similar or better quality LF powders compared to the ones produced through a freeze drying process.
牛乳铁蛋白 (LF) 粉末通过喷雾干燥和冷冻干燥生产。工业上获得的新鲜液态-LF 用作起始原料。测定了喷雾干燥牛乳铁蛋白 (SDLF) 和冷冻干燥牛乳铁蛋白 (FDLF) 粉末的抗氧化能力、水溶解度、水分吸附行为、变性程度和二级结构特征的变化。还测量了 SDLF 和 FDLF 的残余水分含量、水分活度、粒径和无定形/结晶性质。结果表明，与液态-LF 相比，SDLF 和 FDLF 粉末的变性和构象变化可忽略不计。SDLF 和 FDLF 均表现出 II 型吸附行为，具有几乎相同的单层水分含量。SDLF 粉末为无定形，在水中的溶解度超过 98%。SDLF 的抗氧化活性与液态-LF 相似，而在 FDLF 中则降低了约 6%。基于残余水分含量、水分活度、溶解度和LF 在所得粉末中二级结构的保留，发现与冷冻干燥工艺相比，入口温度为 180°C、出口温度为 95°C 的喷雾干燥工艺可生产出质量相似或更好的 LF 粉末。
