Evaluation of Air Oven Moisture Content Determination Procedures for Pearl Millet (Pennisetum glaucum L.)

Figures & data

TABLE 1 Characteristics of moisture determination methods

S/N	Moisture content determination method	Source
1	Air oven, 130 ± 3°C for 2 h, 5 g ground sample denoted as M130t2	ISO R712 (1979)
2	Air oven, 130 ± 3°C for 1 h, 2 g ground sample, denoted as M130t1	AOAC (1980)
3	Air oven, 105°C for 5 h, 15 g ground grains, denoted asM105t5	Chen (2003)
4	105°C for 72 h, 15 g whole grains denoted as M105t72;	ASAE (1982)
5	Air oven, 130°C for 20 h, 15 g whole grains denoted as M130t20;	Jindal and Siebenmorgen (1987)
6	105°C for 48 h, 15 g whole grains, denoted asM105t48	Chen (2003)
7	130°C for 16 h, 15 g whole grains, denoted as M130t16	Noomhorm and Verma (1982); NIAE 16 h

TABLE 2 Moisture contents and standard deviations of pearl millet using different air oven procedures

Moisture contents of air oven procedures, w.b., %
	Ground grain			Whole grain
CM	M130t1	M130t2	M105t5	M105t48	M105t72	M130t16	M130t20	LSD
11	10.10 ± 1.35a	10.97 ± 0.06a,b	10.93 ± 0.05a,b	10.90 ± 0.02a,b	11.01 ± 0.07b	10.85 ± 0.02a,b	10.88 ± 0.01a,b	0.898
19	17.05 ± 0.10a	18.60 ± 0.02b	18.20 ± 0.01c	18.89 ± 0.02a,b	19.00 ± 0.00e	18.87 ± 0.03d	18.90 ± 0.03d	0.075
27	27.00 ± 0.15a	27.00 ± 0.00a	26.60 ± 0.02b	27.00 ± 0.03a	27.01 ± 0.05a	26.82 ± 0.01c	26.99 ± 0.01a	0.106
35	34.00 ± 0.46a	35.00 ± 0.16b	34.93 ± 0.06b	34.86 ± 0.02b	35.00 ± 0.06b	34.73 ± 0.01b	34.80 ± 0.01b	0.327
14	40.00 ± 0.44a	40.40 ± 1.78a	40.60 ± 0.01a	40.20 ± 0.02a	41.00 ± 0.03a	40.43 ± 0.00a	40.53 ± 0.02a	1.215

Means with the same letter on the same row are not significantly different at 5% (p < 0.05) using least significant difference (LSD);

M_130t1: 130°C for 1 h; M_130t2: 130°C for 2 h; M_105t5: 105°C for 5 h; M_105t48: 105°C for 48 h; M_105t72: 105°C for 72 h; M_130t16: 130°C for 16 h; M_130t20: 130°C for 20 h;

C M– Pearl millet conditioned moisture levels, % w.b. Data were mean values of three replicates.

FIGURE 1 Percentage error differences between the 130°C for 1 h. Method versus moisture contents based on 105°C for 72 h.

FIGURE 2 Percentage error differences between the 130°C for 2 h. Method versus moisture contents based on 105°C for 72 h.

FIGURE 3 Percentage error differences between the 105°C for 5 h. Method versus moisture contents based on 105°C for 72 h.

FIGURE 4 Percentage error differences between the 105°C for 48 h. Method versus moisture contents based on 105°C for 72 h.

FIGURE 5 Percentage error differences between the 130°C for 16 h. Method versus moisture contents based on 105°C for 72 h.

FIGURE 6 Percentage error differences between the 130°C for 20 h. Method versus moisture contents based on 105°C for 72 h.

FIGURE 7 Standard deviations based on moisture content determined using 105°C for 72 h (M105t72) and the three methods for ground grain sample: 130°C for 1 h (M130t1), 130°C for 2 h (M130t2), and 105°C for 5 h (M105t5).

FIGURE 8 Standard deviations based on moisture content determined using 105°C for 72 h (M105t72) and the three methods for whole grain samples: 105°C for 48 h (M105t48), 130°C for 16 h (M130t16), and 130°C for 20 h (M105t20).

TABLE 3 Regression models for the 105°C for 72 h method as a function of other air oven moisture determination methods

Air oven method	Regression model	R^2
M130t1		R^2 = 0.9952
M130t2		R^2 = 0.9958
M105t5		R^2 = 0.9993
M105t48		R^2 = 0.9995
M130t16		R^2 = 0.9996
M130t20		R^2 = 0.9995

: Moisture content using the 105°C for 72 h method, % (w.b.);

 , , , , , and represent moisture content (%, w.b.) determined using the 130°C for 1 h (M130t1), 130°C for 2 h (M130t2), 105°C for 5 h (M105t5), 105°C for 48 h (M105t48), 130°C for 16 h (M130t16), and 130°C for 20 h (M105t20) methods, respectively.

FIGURE 9 Residual plot of the relationship between moisture content based on 130°C for 1 h and 105°C for 72 h.

FIGURE 10 Residual plot of the relationship between moisture content based on 130°C for 2 h and 105°C for 72 h.

FIGURE 11 Residual plot of the relationship between moisture content based on 105°C for 5 h and 105°C for 72 h.

FIGURE 12 Residual plot of the relationship between moisture contents based on 105°C for 48 h and 105°C for 72 h.

FIGURE 13 Residual plot of the relationship between moisture content based on 130°C for 16 h and 105°C for 72 h.

FIGURE 14 Residual plot of the relationship between moisture content based on 130°C for 20 h and 105°C for 72 h.