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Journal : KOVALEN: Jurnal Riset Kimia

Isolasi dan Pemurnian Protein dari Lembaga Jagung (Corn Germ) Menggunakan Metode Presipitasi dan Dialisis: Protein Isolation and Purification from Corn Germ Using Precipitation and Dialysis Methods Nancy Siti Djenar; Joko Suryadi
KOVALEN: Jurnal Riset Kimia Vol. 8 No. 1 (2022): April Edition
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/kovalen.2022.v8.i1.15790

Abstract

The protein contained in corn germ can be used as a raw material that has the potential to provide many benefits in the food, pharmaceutical, and plastic industries. Corn germ with the highest content of protein is around 12-18.4%. In this study, protein from corn germ was isolated and homogenized using tris buffer HCl at pH 7.2. To obtain the protein fraction, precipitation was carried out (salting-out) using a solution of (NH4)2SO4 with saturation levels of 25%, 50%, and 70% respectively. The purification process was carried out by dialysis for 24 hours. The dialysis produced pure protein with a concentration of 4.161%. Based on the identification of functional groups using an FT-IR spectrophotometer, it was shown that the isolated and purified corn germ protein contained four absorption bands, including amide A (3211.48 cm-1 and 3226.91 cm-1), amide I (1633 cm-1 and 1629.85 cm-1), amide II (1527 cm-1 and 1552.70 cm-1) and amide III (1296.16 cm-1). The four absorption bands correspond to the wavenumbers of corn protein stated in the literature and are estimated to contain albumin, globulin, glutelin, and zein.
Pengaruh Metode Hidrolisis Terhadap Karakteristik Kimia Senyawa Kalsium Hasil Ekstraksi dari Cangkang Telur Ayam: The Effect of Hydrolysis Methods on Chemical Characteristics of Extracted Calcium Compounds from Chicken Eggshells Yurikke Julieta Permata Putri Sunarya; Yuni Kustiar; Nancy Siti Djenar; Ayu Ratna Permanasari
KOVALEN: Jurnal Riset Kimia Vol. 8 No. 1 (2022): April Edition
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/kovalen.2022.v8.i1.15803

Abstract

Preparation of calcium compounds such as calcium hydroxide, calcium carbonate, and calcium oxide from chicken eggshells can be done through conventional methods that are cheaper and more practical, such as the sol-gel hydrolysis method and the coprecipitation method. In this study, the synthesis of calcium compounds from domestic chicken eggshells was carried out using two methods: the coprecipitation method and sol-gel method. Coprecipitation method consists of acid hydrolysis and alkaline hydrolysis. Sol-gel method consists of modification I and modification II. The AAS results showed that the calcium content from the hydrolysis of acids, alkaline, sol-gel modification I, and sol-gel modification II: 14.50%, 6.64%, 6.68%, and 9.93%, respectively. The FTIR showed that calcium compounds have four characteristic absorption bands, including O–H (3641.60 and 3448.72 cm-1) derived from Ca(OH)2 and H2O products, C=O (2981.95 - 1799 cm-1), and C–O (1448.54 – 874.68 cm-1) both of which from carbonate ions (CO3-) in CaCO3 both from eggshell and from the resulting calcium compounds, and Ca-O (711.73 cm-1) derived from CaO products. The results showed that the modification ll sol-gel method was the best because calcium compounds consisting of CaCO3, Ca(OH)2, and CaO were produced in a smooth texture, white color, and with the highest calcium content compared to other methods.
Pengaruh Penambahan Minyak Zaitun Terhadap Karakteristik dan Reologi Edible Film Berbahan Dasar Gluten: The Effect of Addition of Olive Oil on The Properties and Rheology of Gluten-Based Edible Films Nancy Siti Djenar; Joko Suryadi; Nisa Siti Nursaadah; Erina Putri
KOVALEN: Jurnal Riset Kimia Vol. 8 No. 2 (2022): August Edition
Publisher : Chemistry Department, Mathematics and Natural Science Faculty, Tadulako University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/kovalen.2022.v8.i2.15948

Abstract

Gluten vegetable protein can be used as an alternative source of biopolymer as the basic material for edible film other than polysaccharides. Gluten-based edible films have a poor water vapor barrier and high cohesive and viscoelastic properties, therefore the addition of lipids and plasticizers is required. In this study, olive oil was added to reduce its permeability to water vapor, while glycerin was added to produce a more flexible edible film. The results showed that the addition of 1% olive oil could reduce the lowest water vapor transmission rate of 9.14 g/m2/24 hours with a thickness of 0.248 mm, tensile strength of 16.64 mPa, and elongation of 419.5%. The four characteristics are in accordance with the Japanese Industrial Standard. The antimicrobial testing on edible films showed that the addition of 0-2% olive oil could inhibit the growth of E. coli, while A. niger and R. oryzae 0-2% olive oil could not inhibit the growth of the two fungi. The measurement of optical properties showed that the transparency of the edible film was highest at the addition of 0% olive oil at 55%. The highest opacity value was with the addition of 1% olive oil, which is 2.96. The Fourier Transform Infrared (FTIR) identification showed that the edible film added with 1% olive oil had three characteristic absorption bands from gluten, olive oil, and an absorption band from glycerin. These bands indicate that olive oil, glycerin, and gluten do not react but only physically interact. The measurement using Scanning Electron Microscopy (SEM) and Energy Dispersive Spectrometer (EDS) showed that the microstructure of gluten-based edible film produces a varied structure where the gluten structure network can be clearly observed and contains elements of C, O, N where the intensity of C and O elements of 160-400 cps and 30-100 cps, respectively.