Food Biochemistry and Food Processing (2 edition)

BLBS102-c20 BLBS102-Simpson March 21, 2012 13:35 Trim: 276mm X 219mm Printer Name: Yet to Come

370 Part 3: Meat, Poultry and Seafoods

(A)

(B)

(C)

Raw material

Clean and size reduction

Remove

noncollagenous proteins

Remove fats and pigments

1. Alkaline treatment using 0.1 N NaOH at a ratio of
   1:10 (w/v).


2. Wash thoroughly with distilled water until neutral pH
   is obtained.


3. Stir in 10% butyl alcohol at a ratio of 1:10 (w/v).


4. Wash with distilled water.

Soak in 0.5 M acetic acid

Centrifuge/filter

Supernatant(A)

Residue

Soak in 0.5 M acetic acid

in presence of pepsin

Supernatant(P) Centrifuge Residue

Discard

Supernatant (A)and (P)

Add NaCl to final conc. 2.6 M

in 0.05 M Tri-HCl, pH 7.5

Supernatant Centrifuge

Discard

Pellet

Dissolve in

0.5 M acetic acid

Dialyze against

0.1 M acetic acid

Dialyze against

distilled water

Freeze-dry

ASC ASCor PSCPSC

Figure 20.3.Flow chart for the preparation of acid soluble collagen (ASC) and pepsin soluble collagen (PSC). All procedures are performed

at 4◦C. (A) Preparation of raw material. (B) Extraction. (C) Recovery.

(Duan et al. 2009, Nalinanon et al. 2010, Kittiphattanabawon

et al. 2010a). Collagen from total tissue can be isolated by direct

extraction with organic acids (acetic, chloracetic, citric, lactic)

or inorganic acid (hydrochloric). The yield of extracted collagen

depends on the animal species used and the age and parameters

of extraction (Skierka and Sadowska 2007). Collagen extraction

from different species has been performed using acetic acid.

Collagen extraction is generally achieved by 0.5 M acetic acid

treatment at 4◦C for 24–48 hours. Compared to simply prolong-

ing the extraction time, the use of several consecutive extraction

may get better ASC yield (Sadowska et al. 2003, Regenstein

and Zhou 2007, Skierka and Sadowska 2007). Nalinanon et al.

(2008) found that ASC yield from the skin of threadfin bream

was increased from 12.32% to 34.90% (based on hydroxypro-

line content), when extended the extraction time from 6 to 48

hours. The similar result was observed in collagen extraction

from bigeye snapper skin, in which the yield increased from

7.3% to 9.3% (based on hydroxyproline content) with increas-

ing extraction time from 24 to 48 hours (Nalinanon et al. 2007).

Increasing the concentration of acetic acid used from 0.1 to

0.5 M resulted in the increased yield of collagen extracted from

minced cod skin, from 52% to 59% (dry weight). Re-extraction

of residual matter with 0.5 M acetic acid can be performed to

increase the yield of ASC, particularly in carp bone (Duan et al.

2009), bigeye snapper skin and bone (Kittiphattanabawon et al.

2005).

Skierka and Sadowska (2007) studied the influence of differ-

ent acids on the extractability of collagen from the skin of Baltic

cod (Gadus morhua). The maximal yield of collagen extracted

with 0.5 M citric acid and acetic or lactic acids was 60% and 90%