Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

PCog LAB > (MIDTERM) Extraction of Tannins > Flashcards

(MIDTERM) Extraction of Tannins Flashcards

1
Q

The term _______________________ to denote substances present in plant extracts which were able to combine with protein of animal
hides, prevent their putrefaction and convert them into leather

A

‘tannin’ was first applied by Seguin in 1796

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Comprise a large group of complex substances that are widely distributed in the plant kingdom

A

Tannins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

When tannins occur in appreciable quantities, they are usually localized in
specific plant parts, such as ______________________

A

leaves, fruits, barks or stems

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Usually occur as ___________________ that are difficult to separate because
they do not crystallize

A

MIXTURES OF POLYPHENOLS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Contribute a protective function in ________________

A

barks and heartwoods

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

The characteristic properties of tannins derive from the accumulation within a
moderately sized molecule of a substantial number of phenolic groups many of which are associated with o-dihydroxy and o-trihydroxy orientation within a phenyl ring.

A

Tannins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Non-crystallizable compounds that form colloidal solutions with water

A

Tannins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Possess an acid reaction

A

Tannins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Has a sharp “_______________” taste.

A

puckering

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Soluble in alcohol, glycerin, dilute alkalis

A

Tannins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Insoluble in organic solvents except alcohol

A

Tannins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

4 Classification of Tannins

A
  1. Hydrolyzable Tannins
  2. Condensed Tannins
  3. Complex Tannins
  4. Phlorotannins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

“PYROGALLOL TANNINS”

A

Hydrolyzable Tannins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

May be hydrolyzed by acids or enzymes such as tannase.

A

Hydrolyzable Tannins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

They are formed from several molecules of phenolic acids such as gallic and hexahydroxydiphenic acids which are united by ester linkages to a central glucose molecule

A

Hydrolyzable Tannins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

composed of gallic acid units

A

GALLITANNINS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Hydrolyzable Tannins
Two principal types:

A
  1. GALLITANNINS
  2. ELLAGITANNINS
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

composed of hexahydroxydiphenic acid units

A

ELLAGITANNINS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

“CONDENSED TANNINS; PROANTHOCYANIDINS”

A

Nonhydrolyzable Tannins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Not readily hydrolysed to simpler molecules and they do not contain a sugar moiety

A

Nonhydrolyzable Tannins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Contain only phenolic nuclei but frequently are linked to carbohydrates or proteins.

A

Nonhydrolyzable Tannins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Tend to polymerize when treated with hydrolytic agents, yielding insoluble,
usually red-colored products, known as phlobaphenes

A

Nonhydrolyzable Tannins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Tend to polymerize when treated with hydrolytic agents, yielding insoluble,
usually red-colored products, known as ___________________

A

phlobaphenes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

On dry distillation: yield catechol; these tannins are therefore sometimes called
_________________

A

CATECHOL TANNINS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
On dry distillation: yield catechol; these tannins are therefore sometimes called CATECHOL TANNINS
Nonhydrolyzable Tannins
22
Both hydrolysable and condensed tannins are highly soluble in _________________ but insoluble in organic solvents such as solvent ether, chloroform, and benzene
water and alcohol
23
The general method for the extraction of tannic acid is either with ______________________, or with mixture of water, alcohol, and ether
water- saturated ether
24
If the drug consists of __________________, it may be removed by ether
chlorophyll or pigment
24
In such cases, free acids such as __________________ go along with ether, whereas true tannin gets extracted in water
Gallic and ellagic acid
25
STEPS OF Extraction of Tannins
1. Solid-liquid extraction 2. Vacuum filtration 3. Extract recovery 4. Rotary evaporation 5. Pulverizing
26
Precipitates ____________________
GELATIN AND ALKALOIDS
27
Precipitates ___________________ (and can combine with proteins)
proteins from solutions
28
Precipitated by salts of _______, ___ and _____.
COPPER, TIN, & LEAD
29
Precipitated by strong ________________________ solutions.
potassium dichromate solution or 1% chromic acid
30
Form dark blue or greenish black soluble compounds with _________ salts.
FERRIC
31
Chemical Tests:
* Goldbeater’s Skin Test * Gelatin Test * Phenazone Test * Match Stick Test * Test for Chlorogenic Acid
31
Produce a deep red color with ____________________________
POTASSIUM FERRICYANIDE AND AMMONIA
32
Exposure to tannin solution to Goldbeater's skin (membrane from an Ox intestine)
Goldbeater’s Skin Test
33
Goldbeater’s Skin Test Positive result:
BROWN OR BLACK COLOR ON THE SKIN
34
Gallic acid and other pseudotannins are able to precipitate ________________
Gelatin Test
35
Solutions are sufficiently concentrated to produce precipitation
Gelatin Test
36
All tannins are precipitated
Phenazone Test
37
Phenazone Test Positive Result:
BULKY AND OFTEN COLORED PPT.
38
General test for condensed tannins (cathecins)
Match Stick Test
39
A _______________ is dipped in tannin extract followed by hydrochloric acid and warmed near a flame
match stick
40
Match Stick Test Positive result:
PINK OR RED COLORATION OF WOOD
41
Attributed to __________________________ in the wood yieldin the color
Phlorogloucinol reacting with the lignin
42
A type of pseudotannin
Test for Chlorogenic Acid
43
Extract is treated with aqueous ammonia and exposed to air
Test for Chlorogenic Acid
44
Test for Chlorogenic Acid Positive result:
DEVELOPMENT OF A GREEN COLOR
45
Tannic acid with ferric salts are invariably used in the _____________________
manufacture of inks
46
* Tannic acid with ferric salts are invariably used in the manufacture of inks. * Used for tanning – treating animal hides to produce leather * Employed as a pharmaceutical aid * Used as a mordant. * Invariably employed as clarifying agent * Employed as a coagulant * Used in the large-scale production of gallic acid and pyrogallol. * Employed as a reagent * Precipitating agen
Uses of Tannins
47
Used for tanning – treating animal hides to produce _____________
leather
48
Employed as a _______________
pharmaceutical aid
49
Used as a ____________
mordant
50
Invariably employed as ________________
clarifying agent
51
Employed as a ________________
coagulant
52
Used in the large-scale production of __________________
gallic acid and pyrogallol
53
Employed as a _______________
reagent
54
Precipitating agent
Uses of Tannins

PCog LAB (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions