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Flashcards in Pigments Deck (169)
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1

5 important food quality attributes?

flavor
texture
nutritive value
microbial load
color/appearance

2

describe photosynthesis

trapping light energy from sunlight and using it to syntheisze food

3

what are the major types of chlorophyll?

a and b

4

ratio of a and b chlorophyll in nature?

3:1 (a:b)

5

what colors of chlorophyll a and b?

a: bright green bluish color
b: dull green color

6

solubility of chlorophyll?

fat soluble

7

where are myoglobin and hemoglobin mostly found? what does color intensity depend on?

in red meats

intensity depends on myoglobin concentration

8

difference between heme pigments and chlrophyll?

heme has iron instead of Mg

9

what kind of structure does chlorophyll have?

tetrapyrrole structure

10

how many carbons are in phytol

it is a 20 C unit

11

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

12

describe the structure of a pyrol ring

-N-containing 5 membered hytrocyclic ring

13

what are pyrol rings linked together by?

methylene bridges

14

how many pyrole rings are in one chlorophyll?

4

15

difference between chloro b and a?

b has a methyl group with the pyrole ring

16

what is in the center of chlorophyll?

magnesium

17

molecular weight of chloro?

296g/mol

18

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

19

4 forms/structures of chlorophyll?

1. chlorophyll
2. pheophytin
3. chlorophyllide
4. pheophorbide

20

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)

21

what happens to chlorophyll during canning?

high temp causes removal of Mg

becomes pheophytin

22

how do you form pheophorbide from chlorophyllide?

from pheophytin?

from chlorophyllide: lose Mg

from pheophytin: lose phytol

23

what enzyme causes loss of phytol?

chlorophyllase

24

what happens to chlorophyll with moist cooking methods?

-destruction of tissues
-H ions form acids
-temperature causes breakdown of chlorophyll

25

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

26

what happens to chlorophyll during fermentation?

acid production, causes color loss

27

what happens to chlorophyll with exposure to light and air

oxidation
leads to color loss

28

what is responsible for red color of muscle foods?

heme pigments

29

what is globin and heme?

globin: protein part
heme: non-protein part

30

what kind of structure do myoglobin and hemoglobin have?

tetrapyrrole structure

(4 pyrol rings attached to a central Fe atom)