1、Manufacture, Structure and Properties of Dairy Products,Milk Processing, Milk Powders, and Recombined Milk,Summary,Common unit processes in milk processing Separation Clarification Homogenization Heat-treatment Milk powder drying Protein separation,Milk Processing,Full-fat Semi-skimmed (half fat) Sk
2、im (low or non-fat),Raw Milk Processing,Raw Milk,Separated,Clarified,Heat-treated,Packed,Standardised,Skim-milk,Full-Cream,Cream,Clarification and Separation,Clarification removal of solid impurities Separation skimming, separation of fat from skim milk,Stokes Law (Creaming),vs = 2a2Drg/9h0 a = part
3、icle radius Dr = density difference between particle and aqueous phase g = gravitational constant h0 = aqueous phase viscosity,Centrifugal Clarifier,Milk in,Milk Out,Centrifugal Separator,Milk in,Skim milk,Cream,Heat Treatments,Sterilisation Pasteurisation Ultra-heat treated (UHT),In-Can/Bottle Ster
4、ilisation,High-temperature long time process Typically 105 oC for 20 min Gives long shelf-life Caramelised or cooked flavours Extensive protein damage,In-Can/Bottle Sterilisation,Used for paediatric formulations and enteral formulations where sterility is essential,Rotary Retort,Rotary Retort,Pasteu
5、rization,Least intensive heat-treatment Typically 62-65 oC for 30 minutes, 71-74 oC for 15 s, or 88.3 oC for 1s Kills pathogens Short shelf-life,Plate Heat Exchanger,Plate Heat Exchanger Simulation,http:/ oC for 4-15 s, combined with aseptic packing kills thermophiles long shelf life ( 6 months) sho
6、rt time = less heat damage,UHT,Two types of heating direct e.g. injection of steam into product indirect using heat exchanger (e.g. plate),UHT,Direct,Indirect,T (oC),Time (s), 70 oC,Product damage range,Milk Powder,Standardised milk,Heat treated,Evaporated,Dried,Types of Milk Powder,Whole milk powde
7、r (WMP) Skim milk powder (SMP or NFDM),Types of Milk Powder,WMP Spray dried roller dried SMPlow heat SMP medium heat SMP high heat SMP,Spray Drying,Co-current air flow,Counter -current air flow,Low T,Low T,High T,High T,Spray Drier Demonstration,http:/ Protein Products,Functional properties emulsifi
8、cation gelation thickening nutrition,Milk Protein Products,Precipitated caseins Membrane concentrated whey proteins milk protein concentrates,Precipitation of Milk Protein,pH 4.6,Or Chymosin,Casein Manufacture,Milk,Skim milk,De-fatting,Acid casein,Rennet casein,Lactic casein,Precipitation,Mineral ac
9、id,chymosin,Lactic acid bacteria,Whey stream,Caseinate Manufacture,Acid casein,Sodium caseinate,Calcium casenate,NaOH+heat,Ca(OH)2+heat,Total Milk Proteinate,Skim Milk,Form whey/k-cn complex,Heat + Slightly alkaline,Precipitation,Acid casein,caseinating,NaOH,Ca(OH)2,Ca TMPate,Na TMPate,-lactoglobuli
10、n/-casein complex,Heat +,alkali,Membrane Concentration,Whey proteins only precipitate in high salt alternative is ultrafiltration,Ultrafiltration,Protein,Lactose + minerals,Water,High pressure,Whey Protein Concentrate,Whey stream,Ultrafiltration+drying,Lactic WPC,Acid WPC,Rennet WPC,Cheese WPC,Lacto
11、se + minerals,Milk Protein Concentrate,Skim Milk,Concentrated milk,MPC 70,ultrafiltration,drying,MPC 85,MPC 56,Micellar Casein,Skim Milk,Concentrated milk,Micellar casein,microfiltration,drying,Recombined/Reconstituted Milk,Manufactured where fresh milk not available Middle East South East Asia,Reco
12、nstituted Milk,WMP is shipped to dairy plant reconstituted with water to same total solids as milk heat-treated and packed,Recombined Milk,SMP and anhydrous milk fat (AMF) shipped to recombining plant fat is homogenised with SMP to same fat content and total solids as fresh milk,Recombined Milk,SMP,
13、AMF,Homogenise,Heat-treat,Pack,Principles of Homogenization,Effect of Homogenization,Formation of small, stable fat droplets recreates artificial milk fat globule membrane not same as in fresh milk properties different,Homogenization,Also used to reduce particle size in fresh milk fat droplets more
14、stable to creaming (Stokes Equation) vs = 2a2Drg/9h0,Task,Milk proteins are used as ingredients in a wide range of manufactured food products. Summarize the main products that milk proteins are found in. Choose one particular food product where milk protein is an important ingredient and describe the function of the protein is this particular food.,
