Flashcards in Pigments Deck (169)
5 important food quality attributes?
trapping light energy from sunlight and using it to syntheisze food
what are the major types of chlorophyll?
a and b
ratio of a and b chlorophyll in nature?
what colors of chlorophyll a and b?
a: bright green bluish color
b: dull green color
solubility of chlorophyll?
where are myoglobin and hemoglobin mostly found? what does color intensity depend on?
in red meats
intensity depends on myoglobin concentration
difference between heme pigments and chlrophyll?
heme has iron instead of Mg
what kind of structure does chlorophyll have?
how many carbons are in phytol
it is a 20 C unit
why is phytol fat soluble and not water soluble?
it is a 20 C unit structure, making it mostly hydrocarbon (hydrophobic). Thus it is unable to dissolve in water and highly soluble in fats
describe the structure of a pyrol ring
-N-containing 5 membered hytrocyclic ring
what are pyrol rings linked together by?
how many pyrole rings are in one chlorophyll?
difference between chloro b and a?
b has a methyl group with the pyrole ring
what is in the center of chlorophyll?
molecular weight of chloro?
how many absorption optima do chloro a and b have? which are high or low?
a: has 2 around the same absorbance
b: has 1 high optima, and one low one
4 forms/structures of chlorophyll?
what is the part of the chlorophyll structure that causes water insolublilty?
what happens when it is removed?
what molecule does it become?
the phytol group
removal causes molecule to not be insoluble
chlorophyll becomes chlorophyllide (still has Mg but no phytol)
what happens to chlorophyll during canning?
high temp causes removal of Mg
how do you form pheophorbide from chlorophyllide?
from chlorophyllide: lose Mg
from pheophytin: lose phytol
what enzyme causes loss of phytol?
what happens to chlorophyll with moist cooking methods?
-destruction of tissues
-H ions form acids
-temperature causes breakdown of chlorophyll
what happens to chorophyll during dry cooking?
dry heat will destroy enzyme that breaks down phytol (chlorophyllase)
thus, no destruction of color b/c Mg is not removed
what happens to chlorophyll during fermentation?
acid production, causes color loss
what happens to chlorophyll with exposure to light and air
leads to color loss
what is responsible for red color of muscle foods?
what is globin and heme?
globin: protein part
heme: non-protein part