Summary
Summary Food ingredient Functionality - food proteins
- Course
- Institution
Summary lectures and reader Food Proteins of course Food Ingredient Functionality (FIF) at wur
[Show more]
Seller
FollowxLianne17
Reviews received
Content preview
Food proteins• Introduction to proteins
- Sources of proteins
o Animal proteins
▪ Milk proteins
▪ Egg (white) proteins
▪ Animal by-products (blood/ gelatin)
o Plant proteins (legumins)
▪ Soy proteins
▪ Lupine proteins
▪ Sunflower proteins
o Novel (plant) proteins • Potato proteins • Algae proteins • ‘Leafy’ proteins
- Function of proteins in nature
o Nutrition (milk, soybeans, amino acids)
▪ Source of nitrogen (N) and essential amino acids
o Structure (collagen gelatine)
o Metabolism (homeostasis, enzymes, antibodies)
- Functions of proteins in food
o Nutrition (meat, cheese, nuts)
o Texture (gluten in bread)
o Taste (maillard reaction)
- Proteins, peptides and amino acids
- Occurrence of proteins, peptides and amino acids
o Plant/animal raw materials
▪ Proteins: nutrition, structure, metabolism
▪ Peptides: dipeptides in meat products; glutathione in flour
▪ Amino acids & peptides: hormones
o In food products: formed during production
▪ Amino acids and peptides: Fermentation products (cheese)
o In food products: added as ingredients
▪ Proteins: whey proteins in ice-cream
▪ Peptides: hydrolysates in sport nutrition
▪ Amino acids: non-allergenic infant formula
- Questions:
o How is the function of meat (muscle) proteins in the body related to the solubility of
these proteins? The function of muscle tissue is to give structure to the body.
Therefore these proteins are not soluble.
o How is the function of milk proteins related to the solubility of these proteins The
function of milk proteins is to give nutrition, since the calf will drink the milk, the
proteins should be soluble.
• Amino acids
- Structure of amino acids
o Occurrence:
▪ In nature > 200 different amino acids
▪ In proteins ± 20 amino acids (α -L-amino
acids)
80
,- Stereo-isomers of amino acids
o Occurrence:
▪ In nature (α-)L amino acids
▪ After processing (α -)D amino acids (non-digestible)
- Structure of amino acids
o Occurrence:
▪ In proteins only (α -)L amino acids
▪ In certain peptides also (β-)L amino acids
- Amino acid side chains
o Examples
- Classification of amino acids:
o Side-chain
o Nutritional value
- Questions
o Indicate whether these amino
acids are:
▪ Non-polar, non-
charged
▪ Polar, non-charged
▪ Polar, charged
81
,• Peptides
- Occurrence of peptides
o In nature:
▪ blood (buffering function)
▪ plants (hormones)
o In foods:
▪ bread (glutathion)
o In foods after hydrolysis:
▪ Microbial: fermentation products (cheese, ham)
▪ Enzymatic: protein hydrolysates (infant formula)
- Function of peptides
o Peptides:
▪ Are more reactive than proteins
▪ Can have taste
▪ Are more easily taken up by the body
▪ Are studied for their bio-functional properties
- Peptides: oligomers of amino acids
- Nomenclature:
o peptides
o iso-peptides
- Peptide bond
o Occurrence:
▪ In nature Trans
▪ After processing Cis
82
, - Question
o What is the molecular weight (MW) of the tetrapeptide formed out of these 4 amino
acids?
• Effect of pH on charge
- Charge of proteins
o is affected by pH
o can result in repulsion, or attraction between proteins
o has strong effects on
▪ Solubility Aggregation of protein
▪ Foaming and emulsifying properties
- Protonation equilibria
- Amino acids: basic and acidic character
o pH << pKa: the acid or base is mostly protonated (COOH/NH3+)
o pH >> pKa: the acid or base is mostly deprotonated (COO-/NH2)
- Amino acids: multiple charged groups
o Isoelectric point: the net-charge of the acidic and basic groups of a amino
acid/peptide is zero
83
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller xLianne17. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $4.82. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
65507 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 15 years now