Effect of seed processing treatments on oil quality of Ethiopian sesame varieties

Figures & data

Figure 1. Map showing sesame sample collection areas.

Table 1. Description of sesame varieties used in the experiment.

No	Name of the variety/cultivar	Year of release	Altitude (m)	Rainfall (mm)	Days to maturity	Production (kg/ha)	Seed color
1	Abasena	1990	500-1200	>700	110-120	500-1200	gray
2	Gojam azene	Local cultivar	550-1600	650-1100	100-120	-	gray
3	Humera-1	2011	600-1100	400-650	80-90	800-1000	white
4	Setit-1	2011	600-800	400-650	90-100	700-1000	white
5	Wollega	Local cultivar	1250–1650	700-1100	100-120	-	gray

Figure 2. Flow diagram showing oil extraction process steps from sesame seeds.

Figure 3. Assembled oil pressing machine (a) with perforated barrel and nozzle (b).

Table 2. Mean values of oil content, RI, color, and IV of oils obtained from pre-oil extraction processing treatments of five sesame varieties.

Var	Seed treatments	Oil content (%)	Color	RI	IV (g I2/100 g)
			Red units
AB	Raw	47.1 ± 0.21^j	2.63 ± 0.06^f-^h	1.4700 ± 0.00^b	108 ± 0.04^j
	Roast	50.0 ± 0.23^hi	2.90 ± 0.10^d-^f	1.4701 ± 0.00^ab	111 ± 0.04^d
	Dehull	51.1 ± 0.44^h	5.10 ± 0.44^b	1.4700 ± 0.00^b	106 ± 0.05^n
	Cook	48.9 ± 0.06^ij	2.73 ± 0.12^e-^g	1.4701 ± 0.00^a	109 ± 0.08^h
GA	Raw	53.1 ± 0.99^e-^g	2.53 ± 0.15^f-^h	1.4700 ± 0.00^b	110 ± 0.01^e
	Roast	55.0 ± 0.30^b-^e	3.33 ± 0.06^d	1.4701 ± 0.00^a	112 ± 0.03^b
	Dehull	56.7 ± 0.65^ab	5.10 ± 0.10^b	1.4701 ± 0.00^a	110 ± 0.04^f
	Cook	54.6 ± 0.09^c-^f	3.23 ± 0.06^d	1.4701 ± 0.00^a	110 ± 0.06^e
HU	Raw	53.9 ± 0.31^d-^f	2.27 ± 0.21^hi	1.4699 ± 0.00^c	109 ± 0.02^g
	Roast	55.8 ± 0.11^a-^c	3.27 ± 0.15^d	1.4700 ± 0.00^b	109 ± 0.03^gh
	Dehull	57.5 ± 2.11^a	6.20 ± 0.00^a	1.4699 ± 0.00^c	107 ± 0.05^m
	Cook	54.2 ± 0.40^c-^f	2.63 ± 0.15^f-^h	1.4700 ± 0.00^b	108 ± 0.05^l
SE	Raw	51.4 ± 0.28^gh	2.07 ± 0.06^i	1.4698 ± 0.00^d	111 ± 0.02^c
	Roast	53.0 ± 0.44^fg	2.73 ± 0.12^e-^g	1.4699 ± 0.00^c	109 ± 0.04^i
	Dehull	55.8 ± 0.45^a-^c	3.13 ± 0.06^de	1.4700 ± 0.00^b	108 ± 0.05^k
	Cook	51.7 ± 0.38^gh	2.60 ± 0.20^f-^h	1.4700 ± 0.00^b	108 ± 0.04^j
WO	Raw	53.9 ± 0.35^c-^f	2.37 ± 0.12^g-^i	1.4701 ± 0.00^a	113 ± 0.11^a
	Roast	55.8 ± 0.36^a-^d	2.43 ± 0.06^g-^i	1.4700 ± 0.00^b	113 ± 0.04^a
	Dehull	57.2 ± 0.28^a	4.47 ± 0.06^c	1.4701 ± 0.00^a	111 ± 0.05^d
	Cook	54.1 ± 0.44^c-^f	2.50 ± 0.10^f-^i	1.4701 ± 0.00^a	112 ± 0.02^b

Var.= Variety, SE= Setit-1, HU= Humera-1, AB= Abasena, GA= Gojam Azene, WO= Wollega. Within each column, means sharing the same letter are not significantly different at α = 0.05 level of significance.

Figure 4. Changes in free fatty acid (FFA) value of oil from five sesame varieties due to roasting, cooking and dehulling as compared to the raw (unprocessed).

Note: The results were expressed in mean ± std error. AB = Abasena, GA = Gojam Azene, SE = Setit-1, HU = Humera-1, WO = Wollega.

Figure 5. Changes in peroxide value of oil from five sesame varieties due to roasting, cooking and dehulling as compared to the raw (unprocessed).

Note: The results were expressed in mean ± std error. Variety, AB = Abasena, GA = Gojam Azene, SE = Setit-1, HU = Humera-1, WO = Wollega.

Table 3. Mean values of fatty acid composition (%) of oils obtained from pre-oil extraction processing treatments of three sesame varieties.

atty Acid Comp.	Sesame varieties
	Abasena				Gojam Azene				Humera-1
	Raw	Roasted	Cooked	Dehulled	Raw	Roasted	Cooked	Dehulled	Raw	Roasted	Cooked	Dehulled
C16:0	9.63 ± 0.01^e	9.37 ± 0.02^f	9.21 ± 0.00^g	9.40 ± 0.03f	9.67 ± 0.03^e	9.43 ± 0.03^f	9.41 ± 0.02^f	9.63 ± 0.01^e	10.55 ± 0.03^b	10.52 ± 0.01^b	10.08 ± 0.04^d	10.52 ± 0.00^b
C18:0	5.71 ± 0.01^k	5.40 ± 0.01^l	5.96 ± 0.08^g	5.86 ± 0.01^h-^j	5.77 ± 0.02^jk	5.43 ± 0.04^l	5.98 ± 0.01^g	5.93 ± 0.01^gh	7.25 ± 0.02^d	7.21 ± 0.01^d	7.79 ± 0.01^a	7.37 ± 0.01^c
C20:0	0.65 ± 0.01^g-^i	0.62 ± 0.01^i	0.77 ± 0.01^c-^e	0.68 ± 0.01^gh	0.64 ± 0.00^hi	0.61 ± 0.01^i	0.78 ± 0.00^c-^e	0.70 ± 0.01^fg	0.76 ± 0.00^de	0.75 ± 0.01^ef	0.92 ± 0.01^a	0.86 ± 0.01^ab
C22:0	0.15 ± 0.00^f	0.15 ± 0.00^f	0.16 ± 0.00^d-^f	0.15 ± 0.01^ef	0.15 ± 0.01^f	0.15 ± 0.01^f	0.16 ± 0.00^d-^f	0.17 ± 0.00^b-^f	0.19 ± 0.01^a-^d	0.18 ± 0.00^a-^e	0.19 ± 0.01^a-^d	0.20 ± 0.01^a
ΣSFA	16.1	15.5	16.1	16.1	16.2	15.6	16.3	16.4	18.8	18.7	19.0	19.0
C16:1	0.12 ± 0.00^d-^f	0.18 ± 0.01^a	0.13 ± 0.01^d-^f	0.12 ± 0.00^d-^f	0.14 ± 0.01^c-^e	0.17 ± 0.01^ab	0.13 ± 0.01^d-^f	0.13 ± 0.01^d-^f	0.14 ± 0.01^c-^e	0.16 ± 0.01^a-^c	0.14 ± 0.00^b-^d	0.14 ± 0.00^b-^d
C18:1	41.61 ± 0.01^a	40.18 ± 0.01^d	40.97 ± 0.01^b	40.35 ± 0.02^c	39.76 ± 0.01^e	38.30 ± 0.01^k	39.28 ± 0.00^g	39.48 ± 0.01^f	36.73 ± 0.01^m	35.52 ± 0.02^r	36.15 ± 0.01^p	36.31 ± 0.01°
C20:1	0.32 ± 0.00^c	0.37 ± 0.00^b	0.31 ± 0.00^cd	0.23 ± 0.01^fg	0.37 ± 0.01^b	0.43 ± 0.02^a	0.28 ± 0.01^de	0.25 ± 0.01^ef	0.31 ± 0.01^cd	0.32 ± 0.01^c	0.26 ± 0.02^ef	0.20 ± 0.01^g
ΣMUFA	42.1	40.7	41.4	40.7	40.3	38.9	39.7	39.9	37.2	36.0	36.6	36.7
C18:2n6	41.46 ± 0.01°	43.45 ± 0.00^j	41.90 ± 0.02^n	40.25 ± 0.01^p	43.24 ± 0.01^l	45.16 ± 0.01^b	43.32 ± 0.02^k	42.96 ± 0.01^m	44.38 ± 0.01^e	44.85 ± 0.03^c	43.53 ± 0.02^i	43.17 ± 0.03^l
C18:3n3	0.18 ± 0.01^ij	0.19 ± 0.01^h-^j	0.34 ± 0.01^cd	0.32 ± 0.01^d-^f	0.19 ± 0.01^h-^j	0.21 ± 0.01^hi	0.36 ± 0.01^bc	0.34 ± 0.00^cd	0.16 ± 0.00^j	0.17 ± 0.01^j	0.29 ± 0.00^e-^g	0.27 ± 0.01^g
ΣPUFA	41.6	43.6	42.2	40.6	43.4	45.4	43.7	43.3	44.5	45.0	43.8	43.4
ΣUFA	83.7	84.4	83.7	81.3	83.7	84.3	83.4	83.2	81.7	81.0	80.4	80.1
SFA/UFA	0.19	0.18	0.19	0.20	0.19	0.19	0.20	0.20	0.23	0.23	0.24	0.24
Omega6/Omega3	230.33	228.68	123.24	125.78	227.58	215.05	120.33	126.35	277.37	263.82	150.10	159.89

Within each column, means sharing the same letter are not significantly different at α = 0.05 level of significance.

Table 4. Mean values of fatty acid composition (%) of oils obtained from pre-oil extraction processing treatments of two sesame varieties.

Fatty Acid Compos.	Sesame varieties
	Setit-1				Wollega
	Raw	Roasted	Cooked	Dehulled	Raw	Roasted	Cooked	Dehulled
C16:0	11.04 ± 0.06^a	10.31 ± 0.01^c	10.12 ± 0.02^d	10.22 ± 0.01^c	8.72 ± 0.01^h	8.53 ± 0.01^i	8.36 ± 0.01^j	8.30 ± 0.01^j
C18:0	7.51 ± 0.01^b	7.37 ± 0.02^c	7.57 ± 0.01^b	7.52 ± 0.00^c	5.90 ± 0.01^h-^g	5.83 ± 0.01^ij	6.10 ± 0.02^f	6.26 ± 0.01^e
C20:0	0.81 ± 0.01^b-^d	0.76 ± 0.01^d-^f	0.82 ± 0.01^bc	0.82 ± 0.03^bc	0.76 ± 0.02^d-^f	0.66 ± 0.03^g-^i	0.78 ± 0.00^c-^e	0.77 ± 0.03^c-^e
C22:0	0.18 ± 0.00^a-^e	0.18 ± 0.00^a-^e	0.20 ± 0.01^ab	0.19 ± 0.00^a-^c	0.16 ± 0.01^ef	0.16 ± 0.01^ef	0.17 ± 0.01^c-^f	0.17 ± 0.01^b-^f
ΣSFA	19.5	18.6	18.7	18.8	15.5	15.2	15.4	15.5
C16:1	0.15 ± 0.01^b-^d	0.17 ± 0.01^ab	0.14 ± 0.01^c-^e	0.13 ± 0.01^d-^f	0.11 ± 0.01^gf	0.12 ± 0.00^d-^f	0.11 ± 0.01^e-^g	0.09 ± 0.01^g
C18:1	38.98 ± 0.0^1 h	35.70 ± 0.02^q	36.67 ± 0.01^n	36.99 ± 0.01^l	39.48 ± 0.01^f	38.42 ± 0.01^j	38.86 ± 0.01^i	38.88 ± 0.01^i
C20:1	0.22 ± 0.00^fg	0.32 ± 0.01^c	0.20 ± 0.00^g	0.21 ± 0.01^g	0.40 ± 0.01^ab	0.42 ± 0.01^a	0.32 ± 0.01^c	0.29 ± 0.01^c-^e
ΣMUFA	39.4	36.2	37.0	37.3	40.0	39.0	39.3	39.3
C18:2n6	44.24± .02^f	44.43 ± 0.01^e	43.76 ± 0.01^h	43.33 ± 0.01^k	44.82 ± 0.03^c	45.23 ± 0.00^a	44.53 ± 0.02^d	43.84 ± 0.01^g
C18:3n3	0.21 ± 0.01^hi	0.22 ± 0.01^h	0.29 ± 0.01^fg	0.33 ± 0.01^c-^e	0.20 ± 0.02^h-^j	0.31 ± 0.01^d-^f	0.46 ± 0.01^a	0.39 ± 0.01^b
ΣPUFA	44.5	44.7	44.1	43.7	45.0	45.5	45.0	44.2
ΣUFA	83.8	80.8	81.1	81.0	85.0	84.5	84.3	83.5
SFA/UFA	0.23	0.23	0.23	0.23	0.18	0.18	0.18	0.19
Omega6/Omega3	210.67	201.95	150.90	131.30	224.10	145.90	96.80	112.41

Within each column, means sharing the same letter are not significantly different at α = 0.05 level of significance.