Judul: Rheology and Physicochemical Properties of Spray Dried Glucomannan Extracted From Elephant Foot Yam (Amorphophallus oncophyllus) Tuber
Abstrak: Indonesia has many kinds of cereals and tubers which are rich in carbohydrates. One of the potential tubers in Indonesia is elephant foot yam, also known as iles-iles. Elephant foot yam has two important compounds, glucomannan and calcium oxalate. Mannan flour is made from elephant foot yam tuber and has more glucomannan content than the other component in that flour. Glucomannan has many special characteristics, such as capable to form thick solution in water, capable to form gel and capable to form thin and water impermeable film by adding sodium hydroxide or glycerin. First stage in this research was glucomannan extraction in water, then the glucomannan extract (also called slurry) was dried using spray dryer. During drying process, the solid compounds including glucomannan became flour. Then, some analysis were performed to evaluate the physicochemical and rheological characteristics of the mannan flour. Based on result of the research, grating was the chosen treatment used for tuber size reduction. Meanwhile, gradual water changing for 4 times (ratio of tuber: water was 1:5 for one time water changing, thus the total ratio of tuber : water was 1:20) was the chosen treatment for glucomannan extraction. Browning prevention was performed by soaked the size reduced tuber in 1000 ppm sodium metabisulfite solution for 10 minutes. The highest yield and lightness value on mannan flour obtained from laboratory scale production is from slurry which came from the grating treatment and gradual water changing. The yield and lightness value are 3.10% and 98.74, respectively. Output of mannan flour obtained from pilot plant scale production is 3.15%. Based on result of proximate analysis, mannan flour obtained from pilot plant scale production has 9.96% of water content, 6.70% of ash content, 5.64% of protein content, 1.16% of fat content, and 86.49% of carbohydrate content (by difference). The lightness value of mannan flour obtained from pilot plant scale production is 90.37, while the whiteness value is 87.64. The lightness and whiteness value of mannan flour, both from laboratory scale and pilot plant scale production, are higher than the lightness and whiteness value of commercial mannan flour. Glucomannan content and glucomannan yield of mannan flour are 42.99% and 21.39%, respectively. The elephant foot yam tuber which is used as raw material has 6.29% glucomannan content. Mannan flour obtained from spray drying process has good solubility when rehydrated in water. According to rheology characteristics, viscosity of 10% (b/v) mannan flour solution showed no dependency to shear rate and time while viscosity of 11% (b/v) mannan flour solution showed pseudoplastic and thixotropic behavior. Viscosity of 10% (b/v) and 11% (b/v) mannan flour solution decreased due to the heating process until it reached temperature 90OC. Due to the low measured viscosity, mannan flour obtained from spray drying process cannot be used as thickener and gelling agent. Same rheology measurements were also done to 7 mannan flour obtained from different sources, such as drum drying method, conventional (oven drying) method, and commercial mannan flour.
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Judul: Kajian Proses Pemurnian Tepung Glukomanan dari Umbi Iles- Iles Kuning (Amorphophallus Oncophyllus) dengan Menggunakan Enzim α-Amilase
Abstrak: Elephant foot yam (Amorphophallus oncophyllus) as tuber crops which grows wildly at subtropical and tropical forest in Indonesia, apparently is one of the potential exports commodity. The export of this yam tubers to Japan is usually in the form of chips or flour, which then processed to be a kind of traditional food, “shirataki” noodle and “konyakku” tofu. Elephant foot yam tubers can be purified into a glucomannan flour that has special characteristics. The special characteristics of glucomannan flour among other hydrocolloid is its capability to form thick solution in water, swell by a high swelling power, form gel, form thin film in sodium hydroxide solution or form impermeable thin layer with glycerin. It also has a melting characteristics like agar-agar, so it can be used for microbial growth media. In industry, glucomannan is used as raw material of paper, textile and glue, celluloid material, blasting material, foodstuff, cosmetics and cleaner. The conventional method for preparation of glucomannan flour is by mechanical, like sieving, blowing, and polishing. High purified glucomannan flour is produced by separating starch from yam flour. This study has done in other approach that the utilization of α-amylase as starch digesting enzyme will release the starch from cell glucomannan so it resulted to the high purified glucomanna. This research will examine the effects of t temperature (65 oC, 80 oC, and 95 oC) and enzyme dose (1 Unit/g flour, 2 Unit/ g flour dan 3 Unit/ g flour) to the characteristics of glucomannan flours. The result from preliminary research showed that carbohydrate is the main components in fresh tuber and flour. The α-amylase shows the highest activity in pH 5 and has activity on 1.764,71 U/ml, 3.363,29 U/ml and 13.545,75 U/ml for temperature 65 oC, 80 oC, and 95 oC, respectively Starch content in glucomannan flour after α–amylolysis declined from 10.63 % to 4.76 - 0.40 %, while glucomannan content increased from 28.75 % to 42.35 - 80.53 %. The value of whiteness degree changed from 21.26 % of glucomannan flour before hydrolysis into 19.48 % until 28.37 %. The viscosity of glucomannan declined from 16,833.33 cPs to 1500 - 3925 cPs. The water absorption capability of glucomannan flour changed from 1464.75 % to 1288.78 – 1696.29 %. Bulk density of glucomannan flour before hydrolysis is 741.65 kg/m3 then changed to 641.48 - 776.01 kg/m3 after hydrolysis. Value of pH flour glucomannan before and after hydrolysis had changed from pH 6.58 to around pH 4.90 - 5.21. Hydrolysis temperature, enzyme dose treatment and interaction both of them obviously influenced to the starch content, glucomannan content, and whiteness degree of flour, while the yield and viscosity are only influenced by temperature (p<0,05). Glucomannan flour after hydrolysis and extracted by using ethanol 95 % gives high glucomannan content but has lower value of viscosity. The best treatment for preparing the glucomannan flour by α–amylolysis can be obtained from 65 oC of hydrolysis temperature, 3 U/g flour of enzyme dose for 30 minutes
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Judul: Identifikasi jenis-jenis ordo coleoptera koleksi laboratorium hama hutan fakultas kehutanan
Abstrak: Salah satu ordo yang termasuk ke dalam kelas insekta adalah Coleptera. Coleoptera berasal dari kata coleo yang berarti selubung dan petra yang berarti sayap. Nama daerah ordo coleoptera di Indonesia adalah kumbang. Ordo Coleoptera sebagai komponen penyusun ekosistem mempunyai peranan yang penting dalam kehidupan manusia baik merugikan maupun menguntungkan, tergantung pada cara mengelola potensi ordo Coleptera.
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