Babu K S, Amamcharla J K
Department of Animal Sciences and Industry/Food Science Institute, Kansas State University, Manhattan 66506.
Department of Animal Sciences and Industry/Food Science Institute, Kansas State University, Manhattan 66506.
J Dairy Sci. 2022 May;105(5):3911-3925. doi: 10.3168/jds.2021-21341. Epub 2022 Mar 10.
Micro- and nano-bubbles (MNB) have unique properties and have attracted great attention in the past 2 decades, offering prospective applications in various disciplines. The first objective of this study was to investigate whether venturi-style MNB generation is capable of producing sufficient bulk MNB. A nanoparticle tracking system was used to measure the bubble concentration and particle size of MNB-treated deionized water. The MNB-treated deionized water had a bubble concentration of 3.76 × 10 particles/mL (∼350 million bubbles/mL more compared with control) and a mean particle size of 249.8 nm. The second objective of this study was to investigate the effects of MNB treatment on the microstructure and functional properties of milk protein concentrate (MPC) dispersions. Reconstituted MPC dispersions (21%, wt/wt) without air injection were considered as control (C-MPC), and MPC dispersions passed through the MNB system were considered as MNB-treated (MNB-MPC) dispersions. Control and MNB-MPC dispersions were evaluated in terms of rheological behavior and microstructure. The microscopic observations of MNB-MPC dispersions showed less aggregated microstructures and greater structural differences compared with C-MPC dispersions, therefore lowering the viscosity. The viscosity of MNB-MPC at a shear rate of 100 s significantly decreased to 57.58 mPa·s (C-MPC: 162.40 mPa·s), a net decrease in viscosity by ∼65% after MNB treatment. Additionally, MPC dispersions were spray dried after the MNB treatment, and the resultant MNB-MPC powders were characterized and compared with the control MPC in terms of rehydration characteristics and microstructure. Focused beam reflectance measurement of the MNB-MPC powders indicated lower counts of large particles (150-300 μm) during dissolution, signifying that MNB-MPC powders exhibited better rehydration properties than the C-MPC powders. This study, therefore, recommends the possibility of using MNB treatment for more efficient drying while improving the functional properties of the resultant MPC powders.
微纳气泡（MNB）具有独特的性质，在过去20年中备受关注，在各个学科领域都有潜在应用。本研究的首要目标是探究文丘里式微纳气泡生成方式是否能够产生足够数量的微纳气泡。使用纳米颗粒跟踪系统来测量经微纳气泡处理的去离子水的气泡浓度和粒径。经微纳气泡处理的去离子水的气泡浓度为3.76×10个颗粒/毫升（与对照组相比，多出约3.5亿个气泡/毫升），平均粒径为249.8纳米。本研究的第二个目标是探究微纳气泡处理对浓缩乳清蛋白（MPC）分散液微观结构和功能特性的影响。未注入空气的重构MPC分散液（21%，重量/重量）被视为对照组（C-MPC），通过微纳气泡系统的MPC分散液被视为经微纳气泡处理的（MNB-MPC）分散液。从流变行为和微观结构方面对对照组和MNB-MPC分散液进行了评估。与C-MPC分散液相比，MNB-MPC分散液的微观观察结果显示出聚集程度更低的微观结构和更大的结构差异，因此粘度降低。在剪切速率为100 s时，MNB-MPC的粘度显著降至57.58毫帕·秒（C-MPC：162.40毫帕·秒），微纳气泡处理后粘度净降低约65%。此外，在微纳气泡处理后对MPC分散液进行喷雾干燥，并对所得的MNB-MPC粉末进行表征，并在复水特性和微观结构方面与对照MPC进行比较。对MNB-MPC粉末的聚焦光束反射测量表明，溶解过程中较大颗粒（150 - 300微米）的数量较少，这表明MNB-MPC粉末比C-MPC粉末具有更好的复水性能。因此，本研究建议使用微纳气泡处理有可能实现更高效的干燥，同时改善所得MPC粉末的功能特性。
