Effects of Annealing and Additives on the Gelatinization, Structure, and Textural Characteristics of Corn Starch

Figures & data

TABLE 1 Gelatinization characteristics of native and annealed corn starches

Sample	TO (°C)	TP (°C)	TC (°C)	ΔT (Tc – T0) (°C)	ΔH (J/g)
NC	66.4 ± 0.5^a	70.3 ± 0.5^a	74.8 ± 0.3^a	8.4 ± 0.3^c	4.25 ± 0.13^c
CA45	67.8 ± 0.5^b	71.0 ± 0.3^a	74.5 ± 0.6^a	6.7 ± 0.2^b	2.85 ± 0.12^b
CA55	74.4 ± 0.5^c	76.6 ± 0.6^b	78.4 ± 0.7^b	4.0 ± 0.4^a	0.87 ± 0.08^a

Onset temperature (T_o), peak temperature (T_p), gelatinization conclusion temperature (T_c), enthalpy (ΔH);

Values are the average values ± standard deviation (n = 3);

^a,b,cValues in the same column followed by different letters differed significantly (p < 0.05).

FIGURE 1 DSC thermograms of native corn starch (NC) and corn starches annealed for 72 h at 45°C (CA45) and at 55°C (CA55).

FIGURE 2 Scanning electron micrographs of native corn starch (A, NC), corn starch annealed at 45°C (B, CA45), and corn starch annealed at 55°C (C, CA55) at 1500× magnification.

FIGURE 3 X-ray diffraction (XRD) patterns, from bottom to top, of native corn starch (NC), corn starch annealed at 45°C (CA45), and corn starch annealed at 55°C (CA55).

FIGURE 4 (A) Textural characteristics of different concentrations of NC gels; (B) Textural characteristics of NC gels with different concentrations of sucrose; (C) Textural characteristics of NC gels with different concentrations of glucose; (D) Textural characteristics of NC gels with different concentrations of NaCl; (E) Textural characteristics of NC gels with different pH; (F) Textural characteristics of NC, CA45 and CA55 gels without additives.

TABLE 2 Experimental conditions for texture comparison between native and annealed corn starches

Additive	Glucose	Sucrose	NaCl	pH
Concentration	5%	1%	2%	5
		10%		9

TABLE 3 Texture characteristics of native and annealed starches with different additives and solution pH

Additive	Item	Firmness	Consistency	Cohesiveness	Index of viscosity
		(g)	(g/sec)	(g)	(g/sec)
No additives	NC	34.85 ± 0.46^b	314.92 ± 1.61^b	–18.65 ± 0.70^b	–56.89 ± 0.89^b
	CA45	36.61 ± 0.12^c	339.35 ± 0.78^c	–22.09 ± 0.35^a	–92.28 ± 0.70^a
	CA55	24.90 ± 0.07^a	218.78 ± 0.42^a	–16.06 ± 0.04^c	–10.07 ± 0.27^c
1% sucrose	NC	22.02 ± 0.15^a	218.93 ± 0.49^a	–16.00 ± 0.26^b	–7.00 ± 0.27^c
	CA45	34.36 ± 0.21^b	307.18 ± 0.11^b	–21.04 ± 0.06^a	–74.78 ± 0.00^b
	CA55	35.98 ± 0.80^c	324.71 ± 0.57^c	–20.62 ± 0.55^a	–77.14 ± 0.05^a
10% sucrose	NC	36.19 ± 0.10^a	321.93 ± 0.74^a	–21.46 ± 0.10^c	–83.89 ± 0.40^a
	CA45	37.45 ± 0.10^b	338.76 ± 0.12^b	–22.30 ± 0.18^b	–92.03 ± 0.13^b
	CA55	38.57 ± 0.18^c	343.78 ± 0.48^c	–22.86 ± 0.24^a	–98.63 ± 0.16^c
5% glucose	NC	36.19 ± 0.39^b	322.47 ± 0.86^b	–19.78 ± 0.46^b	–65.34 ± 0.67^b
	CA45	30.15 ± 0.14^a	257.44 ± 0.56^a	–18.02 ± 0.63^c	–29.12 ± 0.25^c
	CA55	36.55 ± 0.98^b	335.21 ± 0.20^c	–21.39 ± 0.22^a	–83.76 ± 0.97^a
2% NaCl	NC	26.86 ± 0.88^a	229.32 ± 0.84^a	–17.46 ± 0.32^b	–12.49 ± 0.72^c
	CA45	39.48 ± 0.24^c	366.35 ± 0.63^c	–21.67 ± 0.46^a	–104.21 ± 0.37^a
	CA55	35.98 ± 0.55^b	330.33 ± 0.92^b	–21.39 ± 0.15^a	–88.54 ± 0.48^b
pH 5	NC	22.58 ± 0.49^a	217.80 ± 0.64^a	–15.50 ± 0.60^c	–8.54 ± 0.12^c
	CA45	35.76 ± 0.18^b	319.34 ± 0.75^b	–20.00 ± 0.43^b	–76.79 ± 0.47^b
	CA55	43.70 ± 0.39^c	412.00 ± 0.70^c	–25.81 ± 0.10^a	–144.05 ± 0.53^a
pH 9	NC	35.27 ± 0.10^c	322.74 ± 0.85^c	–22.72 ± 0.32^a	–94.53 ± 0.22^a
	CA45	20.55 ± 0.54^a	213.67 ± 0.48^a	–15.22 ± 0.24^c	–6.73 ± 0.03^c
	CA55	31.35 ± 0.94^b	270.14 ± 0.21^b	–18.79 ± 0.20^b	–44.31 ± 0.10^b

Values are the average values ± standard deviation (n = 3);

^a,b,cValues in the same column followed by different letters differed significantly (p < 0.05).