Physicochemical Properties of Wheat Gluten Proteins Modified by Protease From Sierra (Scomberomorus sierra) Fish

Figures & data

Table 2 Effect of various inhibitors on the trypsin activity of sierra gut enzyme extract

Inhibitor	Specificity	Substrate	Molar ration*	% Inhibition**
PMSF	Serine	BAPNA	4:1	64 ± 2.62
SBTI	Some serine	BAPNA	2:1	97 ± 2.29
TLCK	Trypsin (serine)	BAPNA	4:1	86 ± 1.23
EDTA	Metallo	BAPNA	1:1	59 ± 1.27
*Enzyme to inhibitor ratio. **Values are averages of triplicate determination with standard deviations.

Figure 1 Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of protease extracted from S. sierra viscera after affinity chromatography. Lane A: molecular weight standards; Lane B: S. sierra trypsin-like enzyme extract.

Table 1 Protein concentration, specific activity and purification level during extraction of trypsin from sierra (Scomberomorus sierra ) gut

Extraction steps	Protein content ^a (mg/ml)	Specific activity (U / mg of protein) ^b	Purification (fold)
Crude extract	4.70	0.04	1.0
Fractionation with ammonium sulfate	2.12	0.12	2.9
Dialyzed fraction	1.86	0.16	3.7
Affinity fraction	0.14	2.22	52.0
^aProtein concentration were determined by the Bradford assay using bovine serum albumin as the standard.
^bSpecific activity with BAPNA (Abs410nm), αMol of p-nitroaniline release/min/mg protein.

Table 3 DH of different protein fractions from gluten of both durum and bread wheat hydrolyzed by semipurified trypsin

Protein fraction	Degree of hydrolysis
Gluten
Durum wheat	1.27^a ± 0.03
Bread wheat	1.40^b ± 0.01
Gliadin
Durum wheat	1.16^a ± 0.02
Bread wheat	1.23^b ± 0.03
Glutenin
Durum wheat	1.36^a ± 0.01
Bread wheat	1.40^b ± 0.02
Data are presented as percentage ± SD of three replicates. ^a,bDifferent superscripts within the same protein fraction mean significant differences at p < 0.05.

Table 4 Variation of isoelectric point (zero zeta potential) between native and hydrolyzed gluten particles

Gluten source	Isoelectric point of native gluten particles	Isoelectric point of hydrolyzed gluten particles
Durum wheat flour	5.1	5.8
Bread wheat flour	5.7	5.8

Figure 2 Zeta potential (electrokinetic potential) of native and hydrolyzed gluten from wheat flours. (a) durum wheat and (b) bread wheat.

Figure 3 Gluten index in response to various enzyme doses at different incubation times. (a) Bread wheat flour and (b) durum wheat flour.

Table 5 Effect of enzyme over farinograms data of bread and durum wheat flour

	Durum wheat flour			Bread wheat flour
Enzyme addition (AU)**	0.00	0.023	0.046	0.00	0.023	0.046
Dough development time (min)	3.00	3.00	3.00	4.75	5.00	4.75
Stability (min)	12.50	11.00	10.50	10.00	10.75	7.75
Water absorption (%)	65	*	*	63	*	*
Consistency falling after 1.5 h incubation and 20 min of extra-mixing (BU)**	90	110	140	180	200	210
*Water absorption was not measured in flour containing enzyme. Water volume determined for 0.00 AU enzyme addition was used in the tests with 0.14 and 0.28 AU. **AU: activity units; and BU: Brabender units.

Figure 4 Effect of enzyme on consistency falling and net consistency falling (NCF) after 1.5 h of incubation.