Technical Challenges (9) Flashcards
what are reasons for low predictability of structural contributions of individual food components?
- integration of proteins w/ polysaccharides
- proteins and polysaccharides change functionality during formulation and processing
- functionality depends on kinetic factors and processing conditions
describe protein-sweetener interactions
- proceeds through maillard rxn or strecker degradation
- requires proper rxn conditions for pH, Aw, temp
- rxns can be controlled by acid, Aw, sulfites
how do sweeteners influence gelatinization point of starch?
they raise temp where gelatinization occurs
describe the interactions of sweeteners w/ fats and oils
they don’t chemically react w/ fats and oils. Instead, they interact physically to impact rheological characteristics via:
- particle size distribution
- moisture released from amorphous sugars
how does the particle size of a sweetener affect the amount of fat needed?
decrease sweetener particle size = increase in surface area = increase need for more fat to maintain the same rheological characteristics
what are the two mechanisms/interactions in which surfactant-biopolymer interactions occur through?
- electrostatic
2. hydrophobic interactions
the binding of surfactants to biopolymers has an influence on what?
bulk physicochemical properties of biopolymer solutions (eg. appearance, rheology, phase behaviour)
describe the critical aggregation concentration
the conc at which the interaction between the surfactant and the biopolymer first occurs
describe what happens as surfactant concentration increases from the critical aggregation concentration
surfactant conc increases until polymer is saturated w/ surfactant
Then micelles start to form
describe interactions b/w emulsifiers and polysaccharides. What are the effects of this?
- surfactants form inclusion complexes w/ starch by inserting their hydrocarbon tails into helical coils formed by amylose or linear regions of amylopectin
- this increases loaf volume, reduced crumb firmness and delays staling (slower retrogradation of starch)
describe direct interactions between emulsifiers and proteins
binding of surfactants to proteins which causes changes in conformation, stability or interactions of protein molecules
describe indirect interactions b/w emulsifiers and proteins
surfactants can compete or displace proteins
describe interactions b/w emulsions and lipids
transitions from one crystal form to another during storage of fat based pdts can cause undesired effects (fat crystallization)
what are 2 main contributors to phospholipid-protein binding?
- electrostatic interactions
2. hydrophobic interactions
how does soy lecithin affect soy proteins?
- lecithin has strong affinity to soy proteins
- emulsifying property of the complex increases by ethanol heat treatment
how does sonicating proteins with egg yolk phosphatidylcholine affect emulsifying properties of proteins?
enhances the emulsifying properties
how do phospholipids affect protein functionality?
improves functionality by forming a conjugate w/ low emulsifying globular proteins
what is LPC?
how does it affect interfacial absorptivity of ovalbumin?
lysophosphatidylcholine
promotes interfacial absorptivity of ovalbumin
which is better at producing emulsion droplets?
a) proteins
b) polysaccharides
proteins are better when used at low conc
which is better at producing emlsions that are stable to a wider range of environmental conditions?
a) proteins
b) polysaccharides
polysaccharides are better
describe how protein polysaccharide complexes are held together.
when are they formed?
by physical or covalent interactions
formed before or after homogenization
how does the addition of lipids affect starch properties?
- reduces swelling and gelatinization
- prevents leaching of amylose from starch when heated
- slows retrogradation
- increases resistance of starch to amylase (forms resistant starches)
what type of protein-starch complexes are most effective stabilizers and emulsifiers?
neutral complexes
what happens when you add starch to a protein gel?
- increases stiffness of resulting gel
- increases temp of peak viscosity of amylopectin starch
- overall influence on rheological properties of dough pdts
