Production of milk foams by steam injection: The effects of steam pressure and nozzle design

Abstract

Please cite this article as: Jimenez-Junca, C., Sher, A., Gumy, J-C., Niranjan, K., Production of milk foams by steam injection: the effects of steam pressure and nozzle design, Journal of Food Engineering (2015), doi: http://dx. AbstractFoam properties depend on the physico-chemical characteristics of the continuous phase, the method of production and process conditions employed; however the preparation of barista-style milk foams in coffee shops by injection of steam uses milk as its main ingredient which limits the control of foam properties by changing the biochemical characteristics of the continuous phase. Therefore, the control of process conditions and nozzle design are the only ways available to produce foams with diverse properties. Milk foams were produced employing different steam pressures (100-280 kPa gauge) and nozzle designs (ejector, plunging-jet and confined-jet nozzles). The foamability of milk, and the stability, bubble size and texture of the foams were investigated. Variations in steam pressure and nozzle design changed the hydrodynamic conditions during foam production, resulting in foams having a range of properties. Steam pressure influenced foam characteristics, although the net effect depended on the nozzle design used. These results suggest that, in addition to the physicochemical determinants of milk, the foam properties can also be controlled by changing the steam pressure and nozzle design.

Peningkatan daya buih susu skim sebagian rekombinasi dengan penggunaan penstabil

“…Kondisi ini bisa terjadi dikarenakan semakin tinggi suhu frothing maka semakin lama proses injeksi uap dan semakin lama proses aerasi. Volume buih yang terbentuk dengan metode injeksi uap sangat berkaitan dengan jumlah udara yang diinjeksikan dan kemampuan protein di permukaan buih dalam menjaga udara yang terperangkap (Jimenez-Junca et al, 2015). Karena itu, semakin lama waktu frothing maka buih yang terbentuk akan semakin banyak.…”

Foaming properties of milk samples collected at various processing stages in a dairy processing factory across two seasons

“…Due to the nature of the steam injection foaming method, which is decided by the practical experience of a steaming operator, any changes in foaming conditions (e.g., initial milk temperature, position of steam wand, type of steam injector, foaming time, final foaming temperature, and way to handle the milk container) result in the production of foam with different properties. 4 The foaming properties of milk are also dependent on many other factors, ranging from source, quality, and composition of milk to milk processing and storage conditions. 5 Although a substantial number of studies on the foaming process of milk have been reported, controlling the foaming process of milk on demand is still a challenge to the dairy researchers and the industry.…”

Moderate Hydrogen Pressures in the Hydrogenation of Alkenes Using a Reactor with Hydrogen Gas Self-Inducing Impeller

“…In the former type, the mixture of liquid and hydrogen gas passes down a fixed bed of catalyst, where bubbles are generated by the collision between the fluids and catalyst particles, while in the latter type, hydrogen-rich recycled gas is delivered as bubbles through a mixture of oil and catalyst particles, where bubbles are generated due to the velocity gradient between the gas and liquid phase. In both types of reactors, it is difficult to generate small bubbles of hydrogen gas because the gas-liquid mixture or gas emerges from ejectors or channels that have a low pressure drop between 1 and 3 bar [7,8]. Measurement of the air bubble size ejected from a channel into water shows that it varies from 0.3 to 1.6 mm from channels [9] or 0.5 to 3 mm from ejectors [10].…”

“…Measurement of the air bubble size ejected from a channel into water shows that it varies from 0.3 to 1.6 mm from channels [9] or 0.5 to 3 mm from ejectors [10]. With such a low pressure drop, it is difficult to generate a high shear rate between gaseous and liquid phases to induce bubble breakup to form small gas bubbles [7,8]. Moreover, large-sized bubbles easily rise to the liquid surface, which consequently lowers the holdup of bubbles in the liquid phase [11], whereas high gas holdup or high gas dispersion in the liquid phase is of importance to improve the kinetics of the gas-liquid reactions [12].…”