Table 2.

Mechanized approaches for production of raw materials (mainly cream) containing size based fractioned native fat globules

Mechanized approach	Process of separation	Average size (diameter) of native MFG	Advantages	Disadvantages	References
Centrifugal separation	1. Two-stage centrifugal separation process was conducted at different temperature (7, 15, 25, and 35 °C), feed flow rate (600, 1200, and 1800 mL/min). First stage it separates whole milk (4% fat) into two fractions and separator did not contain any separating disc (i.e., a modified centrifugal cream separator). Second stage two fractions generated from first stage were concentrated using normal separator	Volume mean particle size at D[4,3] for the cream obtained from one fraction was in the range of 1.35 to 3.28 µm and cream obtained from another fraction was in the range of 4.20–26.70 µm	Operate well at 35 °C without coalescence of fat. Separation efficiency is good	Does not operate well at low temperatures such as below 35 °C	Dhungana et al. (2017)
	2. Two-stage centrifugal separation process was conducted at 55 °C. In first stage milk (standardized to 4% fat) was separated in a modified separator (i.e., separator contained four separating cones and was able to operate at 1200 X g or 4800 rpm) into two fractions. Second stage two fractions generated from first stage were diluted and again concentrated to 36% (w/w) fat using normal separator at 5300 X g. In second stage standardized milk containing 4% (w/w) fat was also concentrated to 36% (w/w) fat using normal separator at 5300 X g	From the experiments three fractions were obtained. A. Centrifuged large MFG with mean size of 4.9 ± 0.1 µm, B. Centrifuged small MFG with mean size of 4.1 ± 0.1 µm, and C. Centrifuged medium size MFG with mean size of 4.4 ± 0.0 µm	By combining a lower number of discs with lower rpm fractionation was possible	Only decrease in rotation speed or decreasing number of discs cannot do fractionation	Edén et al. (2016)
Ultrasonic assisted creaming	Multistage ultrasonic fractionation technique was employed at different frequencies (1 and 2 MHz)	At the last stage of the process dual 1 and 2 MHz was able to produce smallest size fraction (i.e. D [4,3] 3.38 ± 0.03 µm) and at that condition size of largest globule was D [4,3] 4.15 ± 0.05 µm, whereas average fat globule size was 4.28 ± 0.01 µm	Successful to enhance cream separation	Not suitable for specific size based fractionation	Leong et al. (2016)
Membrane microfiltration	A cross flow microfiltration process was applied several times to separate milk to obtain different size fat globules based on membrane pore size	Able to fractionate whole milk into two fractions such as smaller fat globules fraction (i.e. 0.9–3.3 µm) larger fat globules fraction (i.e., 5–7.5 µm)	Is able to separate milk into any fraction	Not commercially viable to obtain milk stream with D [4,3] less than 3.26 µm and fouling is a serious problem	Goudédranche et al. (2000), Briard et al. (2003), Michalski et al. (2004), (2006)