Effect of Thermal and High Electric Fields on Secondary Structure of Peanut Protein

Figures & data

FIGURE 1 FTIR spectrum of raw and microwave processed (100-15) peanut samples.

TABLE 1 Notations for representing (a) the hot air roasting of peanut samples (b) the microwave roasting of peanut samples (c) the high electric field processing of peanut samples

(a)	Temperature (°C)
Time (min)	50	75	100
15	50–15	75–15	100–15
30	50–30	75–30	100–30
45	50–45	75–45	100–45
(b)
Time (min)	50	75	100
5	50–5	75–5	100–5
10	50–10	75–10	100–10
15	50–15	75–15	100–15
20	50–20	75–20	100–20
(c)	Voltage (kV)
Time (min)	10	15	20
60	10–60	15–60	20–60
120	10–120	15–120	20–120
180	10–180	15–180	20–180

TABLE 2 Amide I band frequencies and corresponding protein secondary structure correlations (Adapted from [Carbonaro et al., 2008; Georget & Belton, 2006; Jackson & Mantsch, 1995; Kong & Yu, 2007; Menéndez et al., 1995])

S. No	Structure	Amide I frequency (cm^–1)
1	Aggregated strands (Intra molecular)	1610–1628
2	α helix turns	1630
3	β sheets	1640–1626, 1670–1690
4	α helix	1660–1648
5	3/10 helix (310 helix)	1663–1666
6	Antiparallel β sheets/aggregated strands (Inter molecular)	1675–1695
7	Random coils/Unordered	1640–1650
8	Turns	1662–1672, 1673

FIGURE 2 Variations in relative areas of the bands fitted to the normalized FTIR spectra of the Amide I region (1700–1600 cm^–1) of hot air roasted peanuts.

FIGURE 3 Variations in relative areas of the bands fitted to the normalized FTIR spectra of the amide I region (1700–1600 cm^–1) of microwave roasted peanuts.

FIGURE 4 Variations in relative areas of the bands fitted to the normalized FTIR spectra of amide I region (1700–1600 cm^–1) of high electric field processed peanuts.

TABLE 3 Effect of hot air roasting on protein digestibility (IVPD%) of peanut protein

Time (min)	Temperature (°C)
		50	75	100	Mean
	15	83.58 e	87.84 bcd	90.73 a	87.38 b
	30	86.11 d	88.47 bc	91.00 a	88.52 a
	45	87.02 cd	89.46 ab	91.36 a	89.28 a
	Mean	85.57 c	88.59 b	91.03 a

Common letters types indicate the lack of a significant difference (p > 0.05) based on ANOVA and Tukey’s HSD;

The “mean” represent the mean data independent of the other parmeter.

TABLE 4 Effect of microwave roasting on protein digestibility (IVPD%) of peanut protein

Time (min)	Temperature (°C)
		50	75	100	Mean
	5	85.84 h	88.10 ef	89 cd	87.71 d
	10	87.02 g	89.28 bcd	89.91 abcd	88.74 c
	15	87.56 gf	89.91 abcd	90.28 ab	89.25 b
	20	89.10 de	90.19 abc	90.82 a	90.03 a
	Mean	87.38 c	89.37 b	90.05 a

Common letters types indicate the lack of a significant difference (p > 0.05) based on ANOVA and Tukey’s HSD;

The “mean” represent the mean data independent of the other parmeter.

TABLE 5 Effect of high electric field roasting on protein digestibility (IVPD %) of peanut protein

Time (min)	Voltage (kV)
		10	15	20	Mean
	60	86.56 e	87.56 d	88.47 c	87.53 c
	120	88.38 cd	88.47 c	90.10 b	88.97 b
	180	89.10 c	90.73 ab	91.54 a	90.46 a
	Mean	88.01 c	88.91 b	90.03 a

Common letters types indicate the lack of a significant difference (p > 0.05) based on ANOVA and Tukey’s HSD;

The “mean” represent the mean data independent of the other parmeter.