A study was designed to observe the effect of bubbles created from dissolved CO₂ (0–2000 ppm) on crystallization and melting behavior, fat polymorphs, microstructure, and hardness of anhydrous milk fat (AMF) under nonisothermal crystallization conditions. Calculated amounts of dry ice were added to generate 2000 ppm CO₂ at low partial pressure, and an ultrasound (205 kHz, 10 s; US) treatment was delivered at 35 °C through a noncontact metal transducer on the molten AMF to generate bubbles (~500 nm) of CO₂. The generated CO₂ bubbles were found to induce a higher onset of crystallization temperature during cooling from 35 to 5°C at the rate of 0.5°C min⁻¹. The changes in crystallization behavior owing to the generation of a smaller and significant number of TAG crystals also increased the hardness of the AMF at room temperature and refrigerated conditions. The work suggested the potential use of CO₂ nanobubbles derived from the dry ice with the emission of low power US to control the crystallization behavior and thereby the physical properties of milk fat‐containing dairy products.

中文翻译：

---

CO2气泡对无水乳脂结晶行为的影响

设计了一项研究，以观察在非等温结晶条件下，溶解的CO ₂（0-2000 ppm）产生的气泡对结晶和熔融行为，脂肪多晶型物，微观结构和无水乳脂（AMF）硬度的影响。添加计算量的干冰以在低分压下生成2000 ppm CO ₂，并在35°C下通过非接触式金属换能器在熔融AMF上进行超声处理（205 kHz，10 s； US），以产生气泡（ 〜500 nm）的CO ₂。发现以0.5°C min ^-1的速率从35°C冷却至5°C期间，生成的CO ₂气泡会引发更高的结晶温度开始。。由于生成了较小数量的TAG晶体而导致的结晶行为变化，也提高了室温和冷藏条件下AMF的硬度。这项工作表明，可以利用干冰中产生的CO ₂纳米气泡并以低功率US排放来控制其结晶行为，从而控制含乳脂乳制品的物理性能。