Protein 1
Monday, 11 October 2021 10:32
Milk and egg - important of protein = nutrition, N and essential AA - add to flour (enhance
bread structure), also used to provide emulsifying properties, or foaming properties
(mayonnaise and meringues)
Vegetables and soy beans - alternatives to animal products, helps for allergic
Meat (gelatin) - melt at 37C & good gelling properties
Cereal - moisturizing property, water binding capacity = structure
Primary structure
- Functionality
= AA sequence
○ Nutritional = essential AA (primary structure, AA sequence)
Tertiary structure
○ Physiological =
= 3D form
bio-active peptides (gluten, allergic/intolerant),
anti-nutritional factors = protease inhibitor - inhibit the digestion of proteins
in the digestive tract
○ Physical technological = texture in bread, beer foam
- Different proteins are used for similar functions in different conditions (Foam)
○ Meringue (egg)
○ Cappuccino (milk) Egg white and whey protein, depends on the
○ Beer (wheat) final products property we like to achieve
○ Ice cream (milk)
- Why protein important in food industry
○ Increase flexibility
§ Make new product formulation (milk & fruit), same protein in different
conditions/products (e.g. avoid aggregation)
§ Avoid allergic responses (e.g. gluten free bread), same
product/conditions but different proteins
○ Reduce variability btw batches
○ What we know about protein --> what we want to know about the protein
Isolation of proteins (industrial perspective)
- Isolation --> purity of the protein
- General scheme
○ Plant or animal material --> grinding/extraction centrifugation
○ Soluble fraction --> precipitation/centrifugation
○ Protein enriched fractions --> chromatography (. price)
○ Purified protein fractions
- Principles of isolation
○ Based on particular properties of the protein or the non-protein compounds
○ 1st step = removal of other compound classes
§ Use difference in = solubility (precipitation); size (filtration, size-
, ○ Purified protein fractions
- Principles of isolation
○ Based on particular properties of the protein or the non-protein compounds
○ 1st step = removal of other compound classes
§ Use difference in = solubility (precipitation); size (filtration, size-
exclusion chromatography); charge (ion-exchange chromatography)
○ Separation by size = Micro - Ultra - Nano - Reverse osmosis (remove excess
water)
-
§ Whole milk [MF] --> skimmed milk and Cream [UF]--> Whey & Caseins
[NF] --> Whey protein in different types and different purities (WPC-35,
WPC-50, WPC-95, etc. )
○ Separation based on solubility
§ Uses acid / Rennet --> Caseins removed as solid
§ Caseins (random coil) -- precipitate @ 4-6 pH, *** at natural pH(6.7)
after removal of kappa-casein by rennet
§ Whey protein (globular) --> soluble at 4-6 pI (up to 30g/L)
§ Precipitation induced by Rennet = removal of kappa-casein [Rennet
Casein]
§ Acidification (pH 4-6) [Acid Casein] --> readjustment to pH 6.8 with
NaOH or KOH [Na/K- Caseinate - resolubilized]
§ Ultra or Microfiltration [Micellar casein]
Monday, 11 October 2021 10:32
Milk and egg - important of protein = nutrition, N and essential AA - add to flour (enhance
bread structure), also used to provide emulsifying properties, or foaming properties
(mayonnaise and meringues)
Vegetables and soy beans - alternatives to animal products, helps for allergic
Meat (gelatin) - melt at 37C & good gelling properties
Cereal - moisturizing property, water binding capacity = structure
Primary structure
- Functionality
= AA sequence
○ Nutritional = essential AA (primary structure, AA sequence)
Tertiary structure
○ Physiological =
= 3D form
bio-active peptides (gluten, allergic/intolerant),
anti-nutritional factors = protease inhibitor - inhibit the digestion of proteins
in the digestive tract
○ Physical technological = texture in bread, beer foam
- Different proteins are used for similar functions in different conditions (Foam)
○ Meringue (egg)
○ Cappuccino (milk) Egg white and whey protein, depends on the
○ Beer (wheat) final products property we like to achieve
○ Ice cream (milk)
- Why protein important in food industry
○ Increase flexibility
§ Make new product formulation (milk & fruit), same protein in different
conditions/products (e.g. avoid aggregation)
§ Avoid allergic responses (e.g. gluten free bread), same
product/conditions but different proteins
○ Reduce variability btw batches
○ What we know about protein --> what we want to know about the protein
Isolation of proteins (industrial perspective)
- Isolation --> purity of the protein
- General scheme
○ Plant or animal material --> grinding/extraction centrifugation
○ Soluble fraction --> precipitation/centrifugation
○ Protein enriched fractions --> chromatography (. price)
○ Purified protein fractions
- Principles of isolation
○ Based on particular properties of the protein or the non-protein compounds
○ 1st step = removal of other compound classes
§ Use difference in = solubility (precipitation); size (filtration, size-
, ○ Purified protein fractions
- Principles of isolation
○ Based on particular properties of the protein or the non-protein compounds
○ 1st step = removal of other compound classes
§ Use difference in = solubility (precipitation); size (filtration, size-
exclusion chromatography); charge (ion-exchange chromatography)
○ Separation by size = Micro - Ultra - Nano - Reverse osmosis (remove excess
water)
-
§ Whole milk [MF] --> skimmed milk and Cream [UF]--> Whey & Caseins
[NF] --> Whey protein in different types and different purities (WPC-35,
WPC-50, WPC-95, etc. )
○ Separation based on solubility
§ Uses acid / Rennet --> Caseins removed as solid
§ Caseins (random coil) -- precipitate @ 4-6 pH, *** at natural pH(6.7)
after removal of kappa-casein by rennet
§ Whey protein (globular) --> soluble at 4-6 pI (up to 30g/L)
§ Precipitation induced by Rennet = removal of kappa-casein [Rennet
Casein]
§ Acidification (pH 4-6) [Acid Casein] --> readjustment to pH 6.8 with
NaOH or KOH [Na/K- Caseinate - resolubilized]
§ Ultra or Microfiltration [Micellar casein]
