100% tevredenheidsgarantie Direct beschikbaar na betaling Zowel online als in PDF Je zit nergens aan vast
logo-home
Summary Food ingredient Functionality - interactions in food €2,99   In winkelwagen

Samenvatting

Summary Food ingredient Functionality - interactions in food

 62 keer bekeken  0 keer verkocht

Summary lectures and reader interactions in food of course Food Ingredient Functionality (FIF) at wur

Voorbeeld 3 van de 22  pagina's

  • 17 november 2018
  • 22
  • 2018/2019
  • Samenvatting
Alle documenten voor dit vak (8)
avatar-seller
xLianne17
Interactions in food
• Scope of physical functionality lectures
- Combine ingredients (water, proteins, fats, polysaccharides), structure and stability
(emulsions, gels, dispersions, foams) and macroscopic properties (viscosity, elasticity, yield
stress) together
o Stability depends on interaction between particles
• Interactions in food  many types  on different levels
- Molecular  electrons, atoms, ions, dipoles
- Colloidal  colloidal particles  focus during this course
• Different interactions:  all different strength, range, and properties (dependence on T, pH, salt
concentration)
- Electrostatic repulsion and attraction
- Van der Waals interaction
- Hydrogen bonds
- Hydrophobic interaction
- Salt bridges
- Steric repulsion and bridging interactions
- Depletion interaction
• Strength of an interaction:
- The strength of an interaction is related to the interaction force, which is also called the
interaction potential
- Interaction potential: how easy it is for particles (protein, fat, polysaccharide etc.) to come
together
o Negative: repulsive
o Positive: attractive
- The interaction potential V(r) is by definition equal to the amount of work that has to be
performed in order to bring two particles, that are initially infinitely far apart, to a distance r
- Often: different interactions  determine which one is the most dominant




- Different types of interactions contribute to the total interactions:




1. Electrostatic repulsion and attraction
- Within food, the interactions between charged molecules are
very important
- Electrostatic interactions occur between particles, molecules
or groups of molecules that contain a charge (+ or -)
- Repulsive when charged are the same (- and – or + and +)



10

,- Attractive when the charges are opposite (- and
+)
- How do particles get charged in solution? 
Mainly through the presence of acid/base groups
on the surface (pH dependent)  have a charge
o pH  affects the charge of the particles in
food
o pH of common foods  most foods acidic
- Charge of proteins
o Dissociation/association of acid/base
groups:
▪ Amide groups (acid) and carboxyl groups (basic)




o Proteins have both groups: Can be positively or
negatively charged depending on pH
▪ IEP: the pH at which the net charge on the
amino acid is 0  average/total charge is
neutral/0
➢ Affects how many positive and
negative groups are available 
affects charge of protein
➢ pH above IEP = negative
➢ pH below IEP = positive
▪ Low IEP in higher pH → negatively charged
▪ High IEP in lower pH → positively charged
▪ Protein the same load  reject  no
clumping
▪ Proteins no charge  binding  coagulation
(agglomeration)




o pH 7  some proteins positive charge, and some proteins
negative charge  pH in food really important  determines
the sign of the charge and amount of charge
- Charge of polysaccharides
o Mostly carboxyl groups  can only become negatively charged
o Basic pH  negative charge
o Not the ability to have a positive charge
o How much groups become charged and at which pH depends on the type of groups




o Other groups  come from stronger acids  dissociate easier into charged group 
at low and basic pH
▪ SO42- (sulphates groups) (carrageenan)
▪ PO43- (phosphate groups)
o Example
▪ Pectin: has a lot of carboxyl groups that can be negatively charged


11

, ▪ So pectins are in general negatively charged  pectin is an exception  has
amide and carboxyl group  possibility for positive and negative charge 
act as polysaccharide




- Amount of charged groups
o Possible to calculate amount of
negative/positive charge
o Amount of charged groups can be calculated for each pH value and are related by the
pKa of the polysaccharide
▪ At pKa: amount of charged (+ or -) groups (A-) and neutral groups (HA) are
equal
o Depends on type protein/polysaccharides/available groups and available amount of
those groups
▪ Polysaccharides with low pKa have a lot of negative charges at low pH
▪ Polysaccharides with high pKa have a little negative charges at a low pH
- Summary
o pH and chemical composition are very dependent on the charge and therefore have
an effect on electrostatic interactions
o Proteins
▪ NH2 and COOH groups
▪ Charge depends on pI
▪ Positive below pI
▪ Negative above pI
o Polysaccharides
▪ COOH, SO42-, PO43- groups
▪ Charge depends on pKa
▪ Low charge close to pKa
▪ High charge above pKa
- Electrostatic interaction
o In this case: repulsion  Attraction just the opposite
o The amount of charge will depend how much repulsion will be present and will
therefore determine the distance between particles




12

Voordelen van het kopen van samenvattingen bij Stuvia op een rij:

Verzekerd van kwaliteit door reviews

Verzekerd van kwaliteit door reviews

Stuvia-klanten hebben meer dan 700.000 samenvattingen beoordeeld. Zo weet je zeker dat je de beste documenten koopt!

Snel en makkelijk kopen

Snel en makkelijk kopen

Je betaalt supersnel en eenmalig met iDeal, creditcard of Stuvia-tegoed voor de samenvatting. Zonder lidmaatschap.

Focus op de essentie

Focus op de essentie

Samenvattingen worden geschreven voor en door anderen. Daarom zijn de samenvattingen altijd betrouwbaar en actueel. Zo kom je snel tot de kern!

Veelgestelde vragen

Wat krijg ik als ik dit document koop?

Je krijgt een PDF, die direct beschikbaar is na je aankoop. Het gekochte document is altijd, overal en oneindig toegankelijk via je profiel.

Tevredenheidsgarantie: hoe werkt dat?

Onze tevredenheidsgarantie zorgt ervoor dat je altijd een studiedocument vindt dat goed bij je past. Je vult een formulier in en onze klantenservice regelt de rest.

Van wie koop ik deze samenvatting?

Stuvia is een marktplaats, je koop dit document dus niet van ons, maar van verkoper xLianne17. Stuvia faciliteert de betaling aan de verkoper.

Zit ik meteen vast aan een abonnement?

Nee, je koopt alleen deze samenvatting voor €2,99. Je zit daarna nergens aan vast.

Is Stuvia te vertrouwen?

4,6 sterren op Google & Trustpilot (+1000 reviews)

Afgelopen 30 dagen zijn er 83662 samenvattingen verkocht

Opgericht in 2010, al 14 jaar dé plek om samenvattingen te kopen

Start met verkopen
€2,99
  • (0)
  Kopen