Emulsi Pada Produk Susu

1. Emulsi Pada Produk Susu

3. Chocolate milk and infant formulae

4. Complete nutritional formula

7. Kasein Misel

9. Mengapa susu segar berwarna putih ? • Jawab : • Susu tersusun dari berbagai nutrien yang terlarut dalam air atau terdispersi sebagai koloid • Susu segar bukan hanya merupakan larutan dan dispersi koloid, namun juga merupakan emulsi • Warna putih pada susu segar disebabkan oleh koloid dan emulsi komponen susu (lemak dan protein) dalam fase air.

10. Mengapa susu segar berwarna putih ? • Protein susu - casein micelles • Bentuk, ukuran dan kenampakan misel kasein memberikan warna putih pada susu • Perbesaran 37,500x (garis: 1.2 µm).

11. Koagulasi Susu Segar The coagulation of milk by chymosin includes two separate steps: proteolysis and aggregation

12. Aggregation behavior of emulsifier molecules(a) Head group larger than the tail: micelle formation in water(b) Cylinder-shaped molecule: formation of parallel bilayers(c) Head group smaller than the tail: formation of inverted micelles, enclosing water.

13. A schematic drawing of a lamellar phase.The emulsifier molecules are arranged in parallel sheets in such way that the hydrophilic head groups of the molecules are in contact with water and that the hydrophobic chains are in contact with each other and excluded from water.

14. Misel Kasein Caseins exist in large spherical collodial micells with calcium phosphate. These micelles comprises 93% (w/w) caseins and range in size from 500 to 3000 A in diameter. The calcium and phosphate play a very important role in maintaining the integrity of the casein mucelles, and are commonly referred to as colloid calcium phosphate.

15. Emulsion formation, structure and stability • During homogenisation, fat globules with sub-micron size are formed • Milk proteins migrate to the newly formed fat globule surfaces • Capability to form a stable emulsion is determined by the ability of the protein to unfold at the fat-water interface • Protein load affects the stability of emulsion towards heating and storage

16. Fat globules in recombined milk Natural milk 10 mm

17. Fat globules in recombined milk Recombined (homogenized milk) Natural milk 10 mm 10 mm

18. Fat Globule Stabilization by Milk Proteins Protein at fat/aqueous interface

19. Emulsion destabilisation in recombined milk • Thermodynamically unstable • Mechanisms of destabilisation: aggregation, flocculation, coalescence and creaming

20. Oil droplet Casein micelle Flocculation and coalescence Aqueous phase Whey proteins

21. Oil droplet Casein micelle Flocculation Flocculation and coalescence Aqueous phase Whey proteins

22. Oil droplet Casein micelle Flocculation Flocculation and coalescence Aqueous phase Whey proteins Coalescence

23. Consequences of coalescence Oil Water Coalescence leads to an increase in the rate of separation

24. Particle size distribution – A stable recombined milk 20 18 16 14 12 Frequency (%) 10 8 6 4 2 0 0.01 0.1 1 10 100 Particlesize (um)

25. Particle size distribution – unstable recombined milks 20 16 12 Volume frequency (%) 8 4 0 0.01 0.1 1 10 100 Particle size (µm)