Stability, temperature dependence, and microstructure of high pressure jet-treated dairy foams
Stability, temperature dependence, and microstructure of high pressure jet-treated dairy foams
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DOI：
10.1016/j.foodhyd.2021.106621
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发表时间：
2021-01
影响因子：
10.7
通讯作者：
G. L. Voronin;J. Coupland;F. Harte
中科院分区：
文献类型：
--
作者：
G. L. Voronin;J. Coupland;F. Harte
研究了不同温度下高压射流对全脂牛奶起泡的影响。使用定制的空气注入装置在5 ° C、20 ° C、40 ° C和50 °C下使高压喷射处理的全脂乳（200和400 MPa）发泡，并将泡沫膨胀和泡沫稳定性与未经HPJ处理的对照进行比较。提取泡沫的等分试样（在5 ° C和50 °C下形成）用于近似分析和使用共聚焦扫描激光显微镜（CSLM）可视化。未经HPJ处理的样品在5、20、40和50 °C下的相对泡沫膨胀值分别为45.5 ± 11.3%、0 ± 0%、79.6 ± 9.7%和88.2 ± 2.8%，而经400 MPa处理的样品的泡沫膨胀值分别为36.4 ± 10.8%、60.8 ± 5.7%、50.0 ± 5.3%、60.8 ± 5.7%和60.8 ± 5.7%。71.7 ± 3.0%。值得注意的是，HPJ处理的样品在20 °C下发泡，而对照乳根本不发泡。此外，400 MPa处理的泡沫在所有发泡温度下稳定>2 h，这与未HPJ处理的全脂奶泡沫不同，未HPJ处理的全脂奶泡沫分别在5 °C和40 °C下发泡后在60 s和1490 s内完全塌陷。未HPJ处理的样品的CSLM和近似分析揭示了基于发泡温度的泡沫组成的差异，其中在50 °C下形成的泡沫中存在的脂肪（3.2 ± 0.3%）比在5 °C下形成的泡沫中存在的脂肪（2.5 ± 0.1%）更多，这可能是由于在空气掺入期间液体油（在50 °C下）迁移到空气-水界面的能力。相比之下，基于发泡温度，来自400 MPa处理的乳的泡沫中没有组成差异，反映了与非HPJ处理的泡沫相比存在结构差异，特别是脂肪。400 MPa处理泡沫的CSLM图像中脂肪-蛋白质复合和微米级气泡的证据支持了这一点。
The objective of this work was to study the effects of high pressure jet (HPJ) processing on the foaming of whole milk at different temperatures. High pressure jet-treated whole milk (200 and 400 MPa) was foamed at 5, 20, 40, and 50 °C using a custom-made air injection device and the foam expansion and foam stability was compared to a non-HPJ-treated control. Aliquots of the foams (formed at 5 and 50 °C) were extracted for proximate analysis and visualization using confocal scanning laser microscopy (CSLM). The relative foam expansion values for the non-HPJ-treated sample at 5, 20, 40, and 50 °C were 45.5 ± 11.3%, 0 ± 0%, 79.6 ± 9.7%, and 88.2 ± 2.8%, respectively while the 400 MPa-treated sample foam expansion values were 36.4 ± 10.8%, 60.8 ± 5.7%, 50.0 ± 5.3%, and 71.7 ± 3.0%. Notably the HPJ-treated sample foamed at 20 °C while the control milk did not foam at all. Furthermore, the 400 MPa-treated foam was stable for >2 h at all foaming temperatures, unlike the non-HPJ-treated whole milk foam, which completely collapsed in 60 s and 1490 s after being foamed at 5 °C and 40 °C, respectively. CSLM and proximate analysis of the non-HPJ-treated sample revealed differences in foam composition based on foaming temperature with more fat present in the foam formed at 50 °C (3.2 ± 0.3%) than at 5 °C (2.5 ± 0.1%), likely due to the ability of liquid oil (at 50 °C) to migrate to the air-water interface during air incorporation. In contrast, there were no compositional differences in the foams from 400 MPa-treated milk based on foaming temperature, reflecting that there are structural differences, particularly in the fat, compared to the non-HPJ-treated foams. This was supported by evidence of fat-protein complexation and micron-size bubbles in CSLM images of the 400 MPa-treated foam.