Proximate composition of injera
Moisture content: Significant difference (p < 0.05) was shown in moisture content of injera of potato barely composite products (Table 1). Within an increment in barley flour proportion from 50–100%, an increase in moisture content from 5.01–13.75% was observed in the injera product (Table 1). Perhaps, an increase in moisture content could be due to the high water-binding capacity of the starch in the barley flour. The low moisture content was obtained from a high proportion of potato flour. Similarly, Shevkani, Singh, Kaur, and Rana (2014) reported that amaranths flour has high water-absorption properties.
Ash content: The ash content indicates an estimate of the total mineral content in a given quantity of food substance (Mezgebo, Belachew, & Satheesh, 2018). The ash content of injera sample were statistically similar among the samples and this may be due to both barely and potato are rich in total ash content, but the number expressed in ash content of injera showed higher percentage (Table 1).
Organic matter content: Significant difference (p < 0.05) was shown in organic matter content of potato barely composite injera (Table 1). The highest organic matter content were recorded in whole barely (97.22%) which was followed by B1 (96.87%) but decreased as potato flour proportion increased and as the proportion of potato flour increased organic matter were decreased in general from this finding barely has higher organic matter than potato.
Crude protein: The protein content of injera was significantly affected by potato and barley mix (Table 1).The protein content of samples ranged from 12.87–15.22% (Table 1). Protein content of injera sample was increased with an increased proportion of potato flour till B3 [15.22%] and decreased as the blending ratio increased, which could be due to the high amount of protein in potato flour. This is important for Ethiopians where injera is the major staple food prepared mostly from sole teff flour unless it is not accessible and costly. Above and beyond, both barely and potato-based injera can be a good source of protein for those who are gluten-sensitive.
Crude fiber content: According to the Nutrient content of potato flour and Barley flour the Crude fiber content of potato flour is better compared to barely flour. Crude fiber content of injera from six different formulations of injera showed significantly different at (p < 0.05) and which was between 5.88% [B5] and 9.09% [B3] (Table 1). Relatively higher Crude fiber content was observed in a sample of injera prepared from B3 [9.09%] and which was followed by B2 [8.11%]. Therefore, the Crude fiber content of potato flour is better compared to barely flour. This is vital for many countries like Ethiopia, where potato and barely are produced in many parts of the country.
Table 1:- Shows effects of blending ratios on Proximate Composition of barely and potato composite injera
Treatments
|
MC%
|
ASH %
|
OM %
|
CP%
|
CF%
|
PO
|
11.01b
|
3.3a
|
87.7e
|
14.25abc
|
2.45cd
|
BA
|
13.75a
|
3.23a
|
97.22a
|
13.88abc
|
1.79d
|
B1
|
9.02c
|
3.23a
|
96.87ab
|
14.39abc
|
3.45bcd
|
B2
|
7.55cd
|
3.23a
|
95.45bc
|
14.85ab
|
3.99abc
|
B3
|
6.31de
|
3.25a
|
93.85c
|
15.22a
|
4.55ab
|
B4
|
5.23e
|
2.88a
|
91.22d
|
13.11bc
|
4.95a
|
B5
|
5.01e
|
2.79a
|
90.11d
|
12.87c
|
5.25a
|
CV%
|
12.09
|
31.95
|
1.07
|
7.10
|
26.48
|
LSD%
|
1.75
|
1.75
|
1.75
|
1.75
|
1.75
|
*Mean values followed by the same letter in the column are not significantly different at 5% probability level. According to LSD test; Where;-PO:- potato flour, BA (pure barely),B1 (10:90),B2 (20:80),B3 (30:70),B4 (40:60),B5 (50:50), DM (dry matter),OM(organic matter),ASH (ash ),CP (crude protein ) and CF (crude fiber) , LSD=least significant difference and CV (Coefficient of variation)
Iron, zinc, Calcium and magnesium content of potato barely composite injera and bread: Table 2 showed that, the highest iron content of injera were recorded in B3 (70.89ppm) which was followed by B2 (69.55ppm) and the least were recorded at B5 (50.99ppm), whereas highest zinc content were recorded at B4 (37.53ppm) and statistically similar with B3 (36.92ppm) and the least was recorded at B5 (25.54ppm). The highest calcium and magnesium content of injera were recorded at B4 (684.77 ppm and 517.74ppm) respectively and the least were recorded at B5 (557.99 ppm and 517.74ppm) respectively.
In general, the Magnesium, zinc, iron and calcium content of injera showed significant difference at (p < 0.05) in potato and barley composite blend (Table 2). In the samples from the different blends, Magnesium, zinc, iron and calcium contents of injera increased with the increment of potato proportion, which may be due to the higher amount of Magnesium, zinc, iron and calcium in the potato flour. Incorporation of underutilized crops like amaranthus and potato to different grains for improving mineral content was reported (Bultosa, 2007; Emire & Arega, 2012) to improve the mineral composition both for injera and bread of potato barely composite product.
Table 2:- Showed effects of blending ratios on Fe, Zn, Ca and Mg content of barely and potato composite injera
Treatments
|
Fe[ ppm]
|
Zn [ppm]
|
Ca [ppm]
|
Mg[ppm]
|
Po
|
33f
|
28d
|
648.99d
|
630.41f
|
BA
|
66.98c
|
22.86f
|
678.56d
|
622.99f
|
B1
|
68.99bc
|
30.99c
|
680.24c
|
635.41d
|
B2
|
69.55ab
|
34.6b
|
682.33b
|
642.82c
|
B3
|
70.89a
|
36.92a
|
683.65ab
|
655.84b
|
B4
|
60.55d
|
37.53a
|
684.77a
|
663.59a
|
B5
|
50.99e
|
25.54e
|
557.99e
|
517.74g
|
CV%
|
1.66
|
3.23
|
0.17
|
0.16
|
LSD%
|
1.75
|
1.75
|
1.75
|
1.75
|
*Mean values followed by the same letter in the column are not significantly different at 5% probability level. According to LSD test; Where;- PO:- potato flour BA (pure barely),B1 (10:90),B2 (20:80),B3 (30:70),B4 (40:60),B5 (50:50),CV (Coefficient of variation), Fe[iron],Zn[zinc],Ca [calcium] and Mg [magnesium]and ppm[parts per million] and LSD=least significant difference
Sensory analysis of Potato- barely composite injera
Potato- barely composite injera sensory result
Color: The color of bread and injera tells about the appearance of the bread, how it looks like, if it is appealing to eyes, inviting, and bright. The sensory scores for injera color are presented in Table 3 . The highest mean score of potato barely composite injera were recorded on whole barely (4.17) and this result was similar to that reported by Sanful (2011) where 100% of the panelists prefer the control (100% wheat) compared wheat–taro flour composite bread.
Taste: The results of the sensory taste scores are presented in Table 3. There was a significant difference (p < .05) in the taste of injera due to blending ratio. The highest score was 3.83 (close to extremely like) for whole barely and which was statistically similar with B1 and B2 (3.82) ,The least scores were for B5(2.67 ) . There was a general decrease in the taste score with increase in potato flour proportion. Similar studies reported a decrease in the taste scores of wheat–taro flour composite bread with increased proportion of taro flour (Ammar et al., 2009). This might be due to poor potato flour odor.
Flavor: The flavor of barely potato composite injera was significantly (p < .05) affected by the blending ratio (table 3). Composite injera from whole barely flour proportion of resulted in the highest score (4.08, moderately like) and the least were recorded at B5 (2.75 moderately dislike). The flavor scores decrease with increase in potato flour proportion which could be attributed to the high starch contents of potato flour with bland flavor. This result was in harmony with earlier studies (Ammar et al., 2009).
Appearance: Appearance is the surface characteristics of food materials which attracts the consumer perception. The appearance of potato barely injera was significantly (p < .05) affected by blending ratio .The appearance score for most of the treatment groups from whole barely , B1 and B2 was around moderately like(3.67) and had higher appearance score.
Texture : The texture of barely potato composite injera was significantly (p < .05) affected by the blending ratio (table 3). Composite injera from whole barely flour proportion of resulted in the highest score (4.33, moderately like) and the least were recorded at B5 (2.75 moderately dislike). The texture scores decrease with increase in potato flour proportion.
Roll ability : The roll ability of barely potato composite injera was significantly (p < .05) affected by the blending ratio (table 3). Composite injera from whole barely flour proportion of resulted in the highest score (4.33, moderately like) and the least were recorded at B5 (3, neither like nor dislike). The roll ability scores decrease with increase in potato flour proportion.
Sourness : The Sourness of barely potato composite injera was significantly (p < .05) affected by the blending ratio (table 3). Composite injera from whole barely flour proportion of resulted in the highest score (3.83, near to moderately like) and the least were recorded at B5 (2.92, near to moderately neither like nor dislike). The sourness scores decrease with increase in potato flour proportion and acceptable until B4.
Table.3 shows potato- barely composite injera sensory result
Treatments
|
Color
|
Taste
|
Appearance
|
Flavor
|
Texture
|
Roll ability
|
Sourness
|
A
|
4.17a
|
3.83a
|
3.67a
|
4.08a
|
4.33a
|
4.33a
|
3.83a
|
B1
|
4.08a
|
3.82a
|
3.67a
|
3.75b
|
3.83b
|
3.75b
|
3.5b
|
B2
|
3.92b
|
3.82a
|
3.67a
|
3.45c
|
3.75c
|
3.67b
|
3.42b
|
B3
|
3.56c
|
3.25b
|
3.58b
|
3.42c
|
3.75c
|
3.44c
|
3.25c
|
B4
|
2.67d
|
2.83c
|
2.67c
|
2.9d
|
3.33d
|
3.33d
|
3.17c
|
B5
|
2.5e
|
2.67d
|
2.58d
|
2.75e
|
2.75e
|
3e
|
2.92d
|
CV %
|
1.52
|
0.58
|
0.6
|
1.77
|
0.55
|
1.62 1.47
|
1.58
|
LSD
|
0.08
|
0.14
|
0.035
|
1.11
|
0.03
|
0.09
|
0.09
|
*Mean values followed by the same letter in the column are not significantly different at 5% probability level. According to LSD test; Where, A=Barely, B1=90:10, B2=80:20, B3=70:30, B4=60:40, B5 (50:50), CV= coefficient of variance and LSD=least significant difference