Summary Food Chemistry

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This is the summary of the book "Food Chemistry". The author(s) of the book is/are Diederen. This summary is written by students who study efficient with the Study Tool of Study Smart With Chris.

Summary - Food Chemistry

  • Aldose and ketose

  • Draw the structure of the characteristic group of an aldose. Give after the C-atom his number.
  • Draw the structure of the characteristic group of a ketose. Give after the C-atom his number.
  • Hexose and pentose

  • How many carbon atoms do respectively hexose and pentose have?
    6 and 5
  • D- and L-enantiomer

  • What is a chiral carbon atom?
    A carbon atom with 4 different groups of atoms connected.
  • Pyranose and furanose

  • How many atoms are in the ring structure of respectively a pyranose and a furanose?
    6 and 5.
  • Alpha- and beta-anomer

  • What is the anomeric carbon in saccharides?
    The carbon atom between the double bonded oxygen atom and the OH-group.
  • Which ways point the OH-group at the anomeric carbon of respectively alpha and beta anomers?
    Down and up.
  • Reducing sugar and mutarotation

  • What is a reducing sugar?
    A saccharide with the possibility of an open ring.
  • When is it possible to form an open ring for a saccharide?
    When the OH-group at the anomeric atom is still intact.
  • What is mutarotation?
    The change from an alpha to a beta anomer via the open ring structure.
  • How to measure the change in anomers (when mutarotation takes place)?
    With the optical activity by measuring the rotation of polarization.
  • What is positive dependent on the reactivity of reducting sugars and also of the rate of mutarotation?
  • glucose

  • Glucose most often occurs in the pyranose form.
  • D(+)-glucose is also called dextrose.
  • fructose

  • What are the two main advantages of Fructose?
    The high sweetening capacity and that it causes less dental care.
  • uronic acids

  • Which group is connected to the 6th carbon atom of an uronic acid? (Give the structure from the C6-)
  • Which charge does an uronic acid have above a pH of ~4.
    Negatively charged.
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What are the other 4 main groups of enzymes next to hydrolases and lyases?

  1. Oxidoreductases
  2. Transferases
  3. Isomerases
  4. Ligases
A phenolic compound always contains a benzene ring. How many benzene rings have oligo/polymeric phenolic compounds?
Three or more.
What are the 5 most important properties of phenolic compounds?

Causing browning reactions,
Form complexes with proteins, which gives turbidity and diminished digestibility.
Formation of aroma.
Anti-oxidative effects.
In which three ways the the covalent bonds of the primary structure can be broken?
By proteases (enzymes), using high temperature or high concentrations of acid or alkali.
Depending on the sufficiency of hydrogen, what products can alle be formed during hydrogenation?

Cis can go to trans form and vice versa
saturated acid
double bond shifted to right or to the left
What happens with hydrogenation?
The catalyst (Ni) and in the presence of hydrogen, the unsaturated fatty acids will become more saturated.
Why is water activity important in the rate of fat oxidation?

Because the water surrounds catalysts like metal ions and they form bonds with the hydroperoxides. (between Aw of 0.2 and 0.4)
But <0.2 this is not and the oxygen migrates faster, so then the fat oxidation will be very fast.
And above 0.4 the fat oxidation will also go faster because of the better mobility of catalysts in water.
Lipoxygenase only works on certain 1,4 - cis, cis- pentadiene system. Is C18:1 also affected by this enzyme?
No, because it only has 1 double bond and not 2.
The secondary reaction products of auto-oxidation or photo-oxidation type 2 are aldehydes and ketones. What is different with them in comparison to the hydroperoxides before?
They are volatile carbonyl compounds, which can have "bad" odour or taste.
What does influence the induction time of fatty acids (i.e. The time it takes before peroxydes are formed).
(Natural) antioxidants.