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2013, the inoculum concentration and thickness variation of cassava chips, best mocaf produced is at a concentration of 5 V inoculum and cassava chip thickness of 2 mm, mocaf
produced has a protein content of 3.68 and amounted to 1.63 solubiliti. The process of making mocaf made from cassava chips using Lactobacillus plantarum inoculum produces
the best mocaf on fermentation for 5 days by looking at the levels of protein and fat by 8.5 and 2.8 Lina et al., 2012.
Several parameters commonly used to define the characteristics of mocaf, are degree of whiteness, viscosity using a Brabender, protein content, fat content, swelling power,
solubility and HCN levels Subagio et al., 2012; Misgiyarta et al., 2009; Lina et al., 2012; Darmawan et al., 2013. In this research, the characteristic of mocaf measured were amylose
and amylopectin contents, and the mass loss using Thermogravimetric Analysis TGA.
2. Materials and methods
2.1 Materials
Materials used in this study were white cassava tubers, sodium citrate, Lactobacillus plantarum inoculum, skim milk powder, HCl, NaOH, H
2
SO
4
, amylose potato, distilled water, tapioca flour sagu tani, and wheat four segitiga biru. Inoculum of Lactobacillus plantarum
strains was obtained from the Center for the Study of Food and Nutrition, University of Gadjah Mada. Cassava tubers used were those harvested three days before used for the
experiments.
2.2 Methods Preparation of mocaf consists of three main processes of raw material preparation,
fermentation, and flouring. As a raw material, 500 g of cassava was cleaned and shredded, then mixed with 15 mL of inoculum and 500 ml of water. The fermentation process was
carried out for 48 hours and pH 4 at 28 °C. Flouring process was performed after the fermented cassava pulp was dried, and then ground into flour passes through 80 mesh sieve.
The mocaf was characterized and compared with wheat flour, cassava flour, and tapioca flour, in terms of amylose and amylopectin contents, and mass reduction using TGA
measurement.
2.3 Characterization of mocaf, wheat flour, tapioca, and cassava flour
Measurements of starch content used Luff Schoorl method AOAC International, 1997, amylose content used iodometry method Yuan et al., 2007 and the levels of
amylopectin is calculated by deducting starch content with amylose content. The thermal analysis of all samples were carried out with TGA SSI TGDTA 7300 thermal analyser in a
platinum measuring cell, with the use of Muse Jobs programme for data handling. Measurements were performed in a nitrogen atmosphere gas flow 50 cm
3
min
-1
with the heating rate 15
o
C min
-1
. The samples about 5 mg were heated up to 650
o
C, starting from room temperature. All measurements were repeated at least three times.
3. Results and discussion
The content of amylose and amylopectin of mocaf in starch by weight is almost the same as with wheat Table 1. This shows that the characteristic mocaf almost the same as
wheat. Amylose content in mocaf, tapioca and cassava flour are different due to
Mocaf characterization using thermogravimetric analysis TGA
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fermentation process, because amylose and amylopectin undergo changes during the fermentation process. Changes of amylose and amylopectin content occurs because bond
termination by amylase enzyme produced by the bacterium Lactobacillus plantarum Giraud, 1991. Comparison of the composition of amylopectin and amylose in the starch will affect
the level of viscosity, solubility and degree of starch gelatinization Flach, 2003.
Table 1. Content of amylose and amylopectin based on the weight of the starch. Sample
Starch mg
Amylosa mg
Amylopektin mg
Amylosa Amylopektin
Tapioca 97.87
21.08 76.79
21.54 78.46
Cassava flour 55.13
21.18 33.94
38.43 61.57
Mocaf 50.91
21.69 29.21
42.62 57.38
Wheat flour 42.75
19.33 23.41
45.22 54.78
The pattern of mass reduction of various types of flour containing starch showed a similar pattern Figure 1, but each possess differences of mass reduction which showed that
the levels of amylose and amylopectin different Figure 2. Mass reduction of mocaf almost similar when compared to wheat flour, this suggests that the two types of flour have similar
characteristics. This difference is due to the levels of amylose and amylopectin are different on each flour undergo thermal decomposition Zhang, 2002; Liu, 2009. Thermal
decomposition started to occur at a temperature of 290 °C and there was a decrease in weight percent at temperature of 300 °C with the termination of carbon-carbon bond Liu et
al., 2010.
Figure 1. Representative thermogravimetric curves of tapioca a, cassava flourb, mocafc, and wheat flourd, in analysed range 150 to 450
o
C.
The main results obtained are compiled in Table 2. The higher the amylose contents in starch, then smaller the mass reduction. By looking at the content of amylose and mass
reduction at 300 oC, mocaf almost similar when compare to wheat flour, suggesting that mocaf is the potential flour to be used as a substitute for wheat flour.
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Table 2. content of amylose, amylopectin and mass reduction. Sample
Amylose Amylopektin
Mass reduction
Tapioca 21.54
78.46 91.58
Cassava flour 38.43
61.57 89.24
Mocaf 42.62
57.38 86.91
Wheat flour 45.22
54.78 85.72
4. Conclusion and remarks
