Effect of Comparative Flour of Purple Sweet Potato (Ipomea batatas)
and Wheat Flour of Nutrition Value on Brownies
Emma Zaidar
*
, Rumondang Bulan, Firman Sebayang, M. Zulham Efendi Sinaga and Rina Latipah
Departement of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Sumatera Utara, Medan, Indonesia
Keywords: Purple Sweet Potato Flour, Carbohydrates, Proteins, Fats and Antioxidants.
Abstract: Determination of protein, fat and carbohydrates of brownies with variations of purple sweet potato flour
comparison with wheat flour. Brownies flour made with variation ratio of purple sweet potato flour with
wheat flour that was (80:20), (60; 40), (40:60) and (20:80) with a total weight of 100 grams of flour. The
protein content was determined by the Kjeldahl method, fFat content was determined by continuous
extraction, carbohydrate content was determined by counting aliquots weight reduction as the results of
moisture, ash, protein and fat. The result showed the highest protein content in variation (40:60) which is
7.09% and the lowest (80:20), which is 3.23%. The more purple sweet potato flour added the protein in
brownies was increase. The highest fat content in variation (20:80) is 18.60% and the lowest (80:20) and
(60: 40), which is 0.63%. The more the flour was added the fat content of the brownies was increase. The
highest levels of carbohydrates obtained from the reduction of protein, fat, water and ash. Furthermore, the
antioxidant test on purple sweet potato flour which has antioxidants that are very good for consumption
which have IC50: 173.14 mg / L.
1 INTRODUCTION
Purple sweet potato is one type of sweet potato is
widely grown in Indonesia. Purple sweet potato
contains of nutrients are rich in vitamins (B1, B2, C
and E), minerals (Ca, Mg, K and Zn), dietary fiber
and carbohydrates. Also, purple sweet potato has a
fairly dense purple color for their anthocyanin
pigmen that has spread from skin to the meat section
of the yam. The protein content cultivars are mostly
between 1.5% and 2.5%, including low to moderate
when compared to other vegetables. Although the
quality of protein is rather balanced, there are very
few sulfur-containing amino acids. The sweet potato
is a good source of vitamin C and vitamin B.
(Rubatzky, 1998).
Besides having a great production, which is
about 15-20 tonnes / ha (Joseph et al., 2003) The
stability and a higher anthocyanin content in purple
sweet potato from another source, make it as an
alternative to natural dyes (Kano et al. 2005). Purple
sweet potato convert into flour is one way to save
and preserve the purple sweet potato. Sweet potato
starch is broken down from yams which eliminated
most of water content about 7% (Sarwono, 2005).
Brownies is one type of pound cake. Brownies has
two type which is brownies and baked brownies.
Cake brownies has a constant structure as when the
brownies was cut its looks uniform from pore
crumbs and eaten soft also moist texture.
2 MATERIALS AND METHODS
Brownies production was divided into several steps.
The first step, butter was heated. The second step, 3
eggs were whipped with 100 ml sugar. Then, second
step was mixed and was added with ½ tbsp Baking
powder, ¼ tbsp butter then mixed until homogeny
for 20 minutes. Next step added 100 g of flour with
variation of purple sweet potato flour with wheat
flour (20: 80; 40: 60; 80:20; 60:40). All component
was added mixed and stirred until distributed. Then
added 3 tbsp cocoa powder, chocolate bars, and
melted butter. Then stirred until evenly distributed
over 5 minutes and put into baking pan or for 35-40
minutes.
182
Zaidar, E., Bulan, R., Sebayang, F., Efendi Sinaga, M. and Latipah, R.
Effect of Comparative Flour of Purple Sweet Potato (Ipomea batatas) and Wheat Flour of Nutrition Value on Brownies.
DOI: 10.5220/0008865701820186
In Proceedings of the 1st International Conference on Chemical Science and Technology Innovation (ICOCSTI 2019), pages 182-186
ISBN: 978-989-758-415-2
Copyright
c
2020 by SCITEPRESS – Science and Technology Publications, Lda. All rights reserved
2.1 Determination of Protein
Brownies product was added into Kjeldahl about 0.1
g, then added 0.3 g of selenium and 15 ml of H
2
SO
4
.
The result was destructed with Kjeldahl method at
450
o
C until the solution becomes clear. Distillation
water then inserted into the system. accommodated
the result in a flask which contained of 25 ml of
H3BO3 3% and mixed with 3 drops of Tashiro
indicator. Then titrated with 0.1 N HCl to
determined % N.
2.2 Determination of Fat Content
Wrapped brownies which has dried with oven at
105
o
C with paper into soxhlet tool. Then extracted
with N-hexane for 6 hours at 80
o
C. Then N-hexane
solution was distilled from the extracted fat at 100-
105
o
C. Then put in the desiccator, determined the
constant weigh of sample. Fat content is then
calculated.
2.3 Determination of Water Content
Brownies about 2 g added into cup then inserted in
oven at 105
o
C for 30 minutes. Weigh it the dried
sample then, repeated until constant weight. Water
content is then calculated.
2.4 Determination of Ash Content
Brownies was added into porcelain cup of known
weight. Then inserted into a furnace at 400
o
C for 5
hours until a white ash ago, weighed and calculated
the ash content.
2.5 Determination of Carbohydrate
Calculated the percentage of moisture, ash, fat, and
protein. Then carbohydrate levels was calculated by
calculating the difference between 100% to the sum
of these percentages. Carbohydrate content (%) =
(100 - (protein + fat + water + ash)) (Fadilah, 2002).
2.6 The Antioxidant with DPPH Test
Method
DPPH solution about 5 ml was added into 2.5 ml of
100 ppm purple sweet potato flour, homogenized
and left for 30 minutes in a dark room. After that,
the measured absorbance at the maximum
wavelength of 516 nm. Do the same way to the
sweet potato Flour 200 ppm, 300 ppm and 400 ppm.
3 RESULTS AND DISCUSSION
3.1 Effect of Wheat Flour on A Purple
Sweet Potato Brownies to Protein
Content
The result of Protein content was showed in Figure 1
that increased of the protein value in comparison
brownies with purple sweet potato flour with wheat
flour 80:20, 60:40 and 40:60. This is because the
protein content of purple sweet potato is higher than
wheat flour. The more purple sweet potato flour was
added the highest levels of protein produced.
According to Susilawati & Medikasari (2008) levels
of protein in the purple ubi flour is 2.79 per 100
grams of purple ubi. According to Saragih (2011)
the quality standard is at 5.03. In other hand,
brownies at 20:80 variation was decreased this was
due to the comparison of sweet potato flour with
wheat flour used is not suitable. As the result, it was
decreased the levels of a protein slightly and already
meet the protein content which has been specified.
Table 1: Data nutritional value in comparison brownies
purple sweet potato flour with wheat flour.
Variation
Parameter (%)
Protein
Fat
Water
Ash
CHO
80:20
3.23
0.63
5.07
0.02
88.39
60:40
3.85
0.63
16.16
0.02
76.69
40:60
7.09
14.07
34.36
0.02
41.81
20:80
6.47
18.60
26.34
0.02
45.92
Figure 1: Diffractogram of limestone powder from the
Sidikalang mountains, Dairi, North Sumatra.
3.2 Effect of Wheat Flour on A Purple
Sweet Potato Brownies to Fat
Content
The result of fat content of comparative flour
brownies was showed in Figure 2 that fat content of
brownies was increase with a ratio of purple sweet
potato flour and wheat flour. This is because the fat
content of the flour is higher than the purple sweet
potato flour, the more of flour was added the fat
Effect of Comparative Flour of Purple Sweet Potato (Ipomea batatas) and Wheat Flour of Nutrition Value on Brownies
183
content of the brownies will increase. Acording to
Sudarmadji (1989), the fat content of wheat flour
was 11.3 g per 100 grams of flour while the fat
content in purple sweet potato flour was 0.81 g per
100 grams of purple sweet potato flour (Susilawati
and Medikasari 2011). Fat content of purple sweet
potato flour also will decrease with warming and
drying in the processing of flour so that more purple
sweet potato flour was added to the production of
the fat content of brownies will also be on the wane.
Figure 2: Effect of variation of purple sweet potato flour
with wheat flour on the fat content of brownies.
3.3 Effect of Variation of Purple Sweet
potato Flour with Wheat Flour on
the Water Content of Brownies
The result in Figure 3 was showed the increasing of
the water content of brownies with a ratio of purple
sweet potato flour with wheat flour in the ratio of
80:20, 60:40 and 40:60 and comparison purple sweet
potato flour with wheat flour was decreased 20:80.
This is because the water content in the purple sweet
potato flour over then in wheat flour which is
removes most of the moisture content of about 7%,
and still contained large enough water quantities. So,
the greater the number of purple sweet potato flour
is added in making brownies the water content
contained in these brownies will increase.
Figure 3: Effect of variation of purple sweet potato flour
with wheat flour on the water content of brownies.
3.4 Effect of Variation of Purple Sweet
potato Flour with Wheat Flour on
the Ash Content of Brownies
The result in Figure 4 shows that there was no
changes of ash content of brownies. This because the
same of the physical and chemical properties on the
food material. There was also no change in the
brownies batter.
Figure 4: Effect of variation of purple sweet potato flour
with wheat flour on the Ash content of brownies.
3.5 Effect of Variation of Purple Sweet
potato Flour with Wheat Flour on
the Carbohydrate Content of
Brownies
The result in Figure 5 where the carbohydrate
content was determined by calculating the difference
between 100% with the number of levels of protein,
fat, water and ash. Therefore, when the number of
carbohydrates levels obtained decreasing it will be
increased and if the levels are increasing the levels
of carbohydrates produced will decrease.
Figure 5: Effect of variation of purple sweet potato flour
with wheat flour on the carbohydrate content of brownies.
ICOCSTI 2019 - International Conference on Chemical Science and Technology Innovation
184
3.6 The Antioxidant Activity Test in
The Purple Sweet Potato Flour with
Wheat Flour
The result in Table 2 shows that the purple Sweet
potato flour is not much different from other sweet
potato flour. Based on the IC50 the potential of
purple sweet potato as a functional food ingredient
or food mainly for its antioxidant health. In this case,
the higher value of purple sweet potato the lower the
IC50 of antioxidant and otherwise. IC50 purple
sweet potato flour is 173.14 mg / L.
Table 2: Absorbance measurement result for purple sweet
potato flour.
Sample
Absorbance
Blank
0.801
100 ppm
0.321
200 ppm
0.272
300 ppm
0.225
400 ppm
0.212
Figure 6: Inhibition vs concentration of purple sweet
potato.
3.7 The Antioxidant Activity Test in the
Purple Sweet Potato Flour with
Wheat Flour
IC50 of wheat flour are: 299.49 mg / L.
Table 3: Absorbance measurement flour.
Sample
Absorbance
Blank
0.763
100 ppm
0.485
200 ppm
0.377
300 ppm
0.364
400 ppm
0.369
Figure 6: Inhibition vs concentration of purple sweet
potato.
4 CONCLUSIONS
The more purple sweet potato flour was added, the
higher protein levels produced in the brownies, the
more flour was added, the higher the fat content to
be generated at brownies. While on the carbohydrate
content results in a reduction of levels of protein, fat,
water and ash. However, variations of purple sweet
potato flour in the ratio (40:60) about 7.09% and
(20:80) about 6.47% still have a good protein
content and good yield brownies. Based on the
quality standards of brownies per 100 grams is
5.03%. Antioxidant generated by the purple sweet
potato flour is IC50 173.14 mg/L, while the wheat
flour has IC50 299.49 mg/L.
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