2.1.8.2. Absorbency Under Load (AUL) - BADA

The yellow solution which is containing of ε −TNP lysine was measured by UV-
spectrophotometer at 415 nm. The quantity of reacted lysyl residues in the acylated and unacylated
of albumin / zygomycetes protein by EDTAD was determined to Lysine standard curve [23-36] .
2.1.4. Preparation of Superabsorbent
After acylation, the modified albumin / zygomycetes protein isolate was crosslinked by using
bifunctional crosslinking reagent. A wide type of suitable bifunctional crosslinking agents are
known in the art. Dialdehydes will react with lysine residues to form crosslinks between
polypeptide chains as a backbone structure.
Bifunctional aldehydes are superior crosslinking reagents. In the present research, any type of
dialdehyde can act as a crosslinking reagent but the preferable bifunctional crosslinking reagent is
bifunctional aldehyde which has this structure:
OCH−(CH2) x−CHO
In which X is a numeral of from 2 to 8.The suitable bifunctional dialdehyde is glutaraldehyde
wherein X=3 [21] .
As follow, acylated protein solution 10% (w/w) was made of deionized water and pH was adjusted
at 9 by pH meter (Model 3505, Jenway analytical instruments). To 10 ml of this solution was
added suitable amount of 25% aqueous solution of glutaraldehyde to crosslink the modified
protein. After the addition of glutaraldehyde to solution, the mixture was roughly stirred and
allowed to cure overnight at room temperature. The cured gel was dried in oven (Termaks) at
40 o C and it was milled in mortar. Flow charts of albumin and zygomycetes protein-based
superabsorbent production are presented in Figure 19, 20.
2.1.5. Determination of Water Uptake
The water uptake of protein-based hydregel was determined in the following procedure, for
determination of the water absorbency of the hydrogels; the particles were used with 40-60 meshes
of amorphous shape.
36