Quality Improvement of Cassava Flour of Local Variety of Ternate Through Fermentation Method (Application on Traditional Food of North Maluku

Cassava is utilized as one of the main food substances in North Maluku society and it has potential for food diversification due to its special quality compare to other products. Cassava commodity can be processed into composite flours with fermentation methods and it is as prominent of food resources and has low of Cyanide content (HCN). This research used two phases of Program Random Completes; it used fermentation period of cassava with 5 levels: 24,36,48,60, and 72 hours. And the utilization phases of composite flours the making of sagu lempeng. The result of this research showed that with long period of fermentation had produce cassava flours with cyanide content of 16, 41–56, 93 ppm with initial content of cyanide as big as 109,02 ppm. The highest cyanide content was found with fermentation period of 24 hours and lower fermentation of 72 hours. The characteristic of sagu lempeng with chocolate and orange taste has 0.72 and 0.55 g total fats, 1.05 and 0.57 g protein, 86.9 and 86.28 g total carbohydrate, 2.86 and 1.35 g rough standard fiber. Keywords— cassava, fermentation, HCN, composite flours, sagu lempeng


I. INTRODUCTION
The utilization of cassava in North Maluku is considered high. It is indicated by the harvest area and production of crops by regency or municipality, especially for cassava, is 11,770 ha with average of production 34,621 ton/year, which is consumed directly by the society. Cassava is one of main food for North Maluku societies and is a potential food as food diversification in general [2].
Cassava plant contains gluco-cyanide in form of toxic aglicon that releasable through hydrolysis process by linamarase enzyme and resulting in hydrogen cyanide [1]. Direct consume of cassava can cause cyanogenesis that give dangerous toxic effect. 50 mg/kg (ppm) of cyanide content in the material is considered safe for consumption [3].
Traditional processing of cassava has proven to be able to reduce cyanide level by washing, submerging, cooking and drying the product to be processed as gaplek. Repeating washing and submerging processes can reduce cyanide content for 50% and level of starch in the cassava. Through drying process, the cyanide content in cassava can reduce until 1/16 of total cyanide [4].
The utilization of cassava material through fermentation technique to decrease the level of cyanide is needed. The result of the fermentation process will be further processed into cassava flour as the main raw material in the making of sagu lempeng, which is the traditional food of North Maluku society. The process can give value added to the local food in term of food security and diversification aspects. Sagu lempeng has comparative advantage than other foods due to its easy process and it can be keep for a long period.

II. MATERIAL AND METHOD
The main material used was cassava variety of Ternate 50 kg. The material was obtained from crops farmers in Jaya Tidore Village. The method in making cassava flour resulting from fermentation process is started with peeling, washing, and fermentation with different time, grated, pressing, and drying processes.
Experiment design used in the research was completely randomized design arranged in factorial with two steps. The first step was the length of cassava fermentation with single factor consisted of 5 levels: 24, 36, 48, 60 and 72 hours of fermentation time. Every treatment was repeated 4 times; therefore there were 20 experimental unites. The second step was the utilization of the best cassava flour resulted from fermentation in the making of sagu lempeng.

A. The Experiment
In the first step of experiment, cassava was sorted, peeled, washed, packed in a plastic bag for the period of fermentation, grated, pressing and dried. The second step was the making of flat sagu using flour resulted from the best result of cassava fermentation. The process was started with filtering, mixing, molding, and cooking to create sagu lempeng sheet. The next process was shortening the size and packing. Observation was conducted on the characteristics of cassava from local variety of Ternate before and after the fermentation. It consisted of cyanide level, degree of acidity and starch level. Observation on sagu lempeng product was conducted on starch level, protein level, rough fiber, total fat and texture.

III. RESULT AND DISCUSSION
Result from the analysis of material used in the making of cassava flour, which is local variety of cassava of Tidore is presented in Table 1 and 2.

A. Characteristics of Cassava after Fermentation
Decrease in cyanide content after fermentation process of cassava. The average of highest cyanide level was found in a treatment of fermentation period of 24 hours of 222.37 ppm/bk. The lowest cyanide level was found in a treatment of period fermentation of 72 hours of 59.45 ppm/bk (Fig. 1).   Sagu lempeng is made from cassava flour resulted from fermentation of half wet or half dry cassava (Fig. 4) The tuber of local variety cassava of Tidore has dark brown color and its tuber flesh is white. The average cyanide level of the cassava is 266.29 ppm/bk, which is more than > 100 pm; therefore, it belongs to bitter cassava group. The level of cyanide in the cassava is considered high and exceeds the safe level for consumption; therefore direct consumption can be toxic. Fermentation process in the research was expected to be able to reduce the level of cyanide in the raw material up to safe level.

Fig. 4. Product Sagu Lempeng, Food Traditional North Maluku
The smaller the size of raw material the lower is the level of cyanide in the cassava after the fermentation. The reason is the smaller the size the bigger is the surface area; thus, the contact of linamarase with linamarin is faster. With faster enzyme activity in the breakdown of linamarin, the number of cyanide acid (HCN) released is bigger; therefore the number of cyanide in the raw material is low [3].
Longer fermentation shows decrease in cyanide level. It is means that pressing and drying processes can reduce cyanide level in cassava. Decrease in cyanide level due to those processes can be related to the dissolved of cyanide formed during the fermentation with water during pressing process, in which it is related to the property of cyanide that water soluble [7].
Drying process is also has influence in decreasing the level of cyanide in raw material for cyanide will evaporate during the process. Cyanide is chemical solution containing CN group with triple carbon atom bound to nitrogen atom. Cyanide is non-colorful solution, very toxic and easy to evaporate in room temperature of 26 0 C. Hydrogen cyanide is a weak acid and it turns into CNion in a solution containing water. Drying process was conducted using cabinet with temperature of 60 0 C for approximately 6 hours. Therefore, using high temperature for drying, cyanide formed during fermentation process will evaporate since the temperature is higher than the boiling point of cyanide [4].
Cassava flour resulted from 72 hours fermentation process of 17.64 ppm/bk is within the safe limit for consumption based on quality requirement of SNI 01-2997-1992 for cassava flour since the cyanide acid level is under 40 ppm/bk. The level of cyanide in a body that exceeds the safe limit can have dangerous toxic effect. When consuming cassava without removing linamarin residue and its fractions, inside a body, linamarin can be dissolved by linamarase resulted in by bacteria in digestive tract and releasing cyanide [3]. Compare to its precursor, the toxicity of cyanide is stronger [7]. The decrease percentage of cyanide level in cassava after fermentation is increasing with the increasing period of fermentation. It is related to the breakdown of cyanogenicglucoside during fermentation by linamarase enzyme and βglucosidase either in cassava tuber or resulted by microorganism. Total mold is increasing along with the decrease in cyanide level in cassava [6]. With the increasing of total mold, the number of β-glucosidase enzyme resulted by mold is increasing; therefore, process of cyanide breakdown into cyanide acid (HCN) will be increasing. Higher HCN released causes lower cyanide level in cassava. The decrease percentage of cyanide level in cassava flour is fluctuate due to the influence of pressing and drying processes and it is related to water level in material after fermentation in which cyanide is water soluble and easy to decompose in higher temperature [6]. HCN level contained in gaplek and cassava flour is under 50 mg/kg. It indicates that submerging and drying are efficient in decreasing the level of HCN. In addition, peeling the cassava tuber and pressing it using mechanic press has able to decrease cyanide level up to 33% [5].
Sagu lempeng is made from cassava flour resulted from fermentation of half wet or half dry cassava. The resulted sagu lempeng contains carbohydrate total of 86.9 g but low protein level. Societies in North Maluku, in general, consume sagu lempeng as their main food, a substitution to rice. Sagu lempeng is chosen more to the texture value of the product. The use of good fermentation method can determine whether or not sagu lempeng is safe to consume as a main food or snack.

IV. CONCLUSIONS
Cassava flour resulted from 72 hours fermentation process of 17.64 ppm/bk is within the safe limit for consumption based on quality requirement of SNI 01-2997-1992 for cassava flour since the cyanide acid level is under 40 ppm/bk. Sagu lempeng is made from cassava flour resulted from fermentation of half wet or half dry cassava. The resulted sagu lempeng contains carbohydrate total of 86.9 g but low protein level.

ACKNOWLEDGMENT
Many thanks to BPTP North Maluku Province as the provider of basic material has developed the loccal variety of Ternate cassava. Dirjen DIKTI that has given fund during the time of education and research. The Regency Government of Sula Archipelago that has also given the fund to smoothen the process of accomplishing the research.