Modifikasi pati dilakukan untuk memperbaiki sifat fungsional pati dan memperluas penggunaan pati dalam produk pangan. Modifikasi pati menjadi dekstin dapat dilakukan baik secara fisik, kimiawi, atau kombinasi fisiko-kimia. Pada penelitian ini dilakukan modifikasi pati dengan kombinasi pregelatinisasi-steam explosion (Pregel-SE), dan kombinasi pregelatinisasi-asam sitrat-steam explosion pada pH 4 (pregel-pH-SE4) dan pH 3 (pregel-pH-SE3) untuk produksi dekstrin. Tujuan dari penelitian ini adalah untuk memperoleh metode hidrolisis terbaik dalam pembuatan dekstrin. Produk yang dihasilkan diamati tingkat kelarutan, berat molekul (Mw), dextrose equivalent (DE), Spectra Fourier Transform Infrared (FTIR), SEM, dan viskositas pasta. Hasil menunjukkan bahwa kondisi terbaik modifikasi pati menjadi dekstrin diperoleh pada perlakuan pregel-pH3-SE. Pada perlakuan ini diperoleh kelarutan 75,94 %, berat molekul 60100 g/mol dan DE 15,92%. Pita vibrasi baru terlihat di wilayah bilangan gelombang 1717 cm-1 pada analisis FTIR. Hasil SEM menunjukkan bahwa bentuk granula pati yang bulat sudah tidak terlihat setelah kombinasi perlakuan. Pengujian RVA menunjukkan penurunan viskositas berkorelasi positif terhadap penurunan berat molekul, peningkatan kelarutan dan DE setelah kombinasi perlakuan ditingkatkan. Starch modification is performed to improve the functional properties of starch and starch utilization in food products. Modification of starch, such as dextrin, can be performed by physical and chemical methods, or a combination method, such as physico-chemical. In this research, starch modification was carried out by a combination between pregelatinization and steam explosion (Pregel-SE), a combination between pregelatinization, citric acid and steam explosion at pH 4 (Pregel-pH-SE4) and at pH 3 (Pregel-pH-SE3) for the production of dextrin. The objective of this research was to obtain the best method for dextrin production. The results were observed, such as levels of solubility, molecular weight (Mw), dextrose equivalent (DE), Spectra Fourier Transform Infrared (FTIR), SEM, and pasting properties (RVA). The results showed that the best condition of starch modification for dextrin production was obtained by Pregel-pH3-SE. Solubility, molecular weight, and DE of dextrin were 75.94%, 60100 g/mol, and 15.92%, respectively. A new peak was observed in the region of the wavenumber 1.717 cm-1 at FTIR analysis. SEM analysis indicated that the round form of starch granules did not observed after the treatments. RVA analysis showed that the decrease in viscosity was correlated with a decrease in molecular weight, an increase in solubility, and DE after the treatments.

Abstract. Yusra S, Hidayat C, Pranoto Y, Anwar C. 2020. Physical and chemical characteristics of stem starch and sheath flour from oil palm tree (Elaeis guineensis). Biodiversitas 21: 896-902. Replanting old oil palm plantation with a new plant produces a large volume of cleared trees. Yet, the utilization of these by-products is still limited. The objective of this research was to explore and characterize the physicochemical properties of the oil palm stem starch (SS) and sheath flour (SF). SF and SS were extracted by a wet extraction method. Results showed that starch contents of SS and SF (after three times of washing) were 95.56±0.01% and 37.03 ± 0.72%, respectively. Amylose and amylopectin contents of SS were higher than that of sheath starch. Besides, SF contained high protein (19.28% db) and lipid (9.27% db). Protein was also confirmed by FTIR analysis. SF also contained polyphenol. The starch granular was smooth with a clean surface. The granules of SF are classified as very small granules (2-5 µm) while those of SS as small to medium granules (5-25 µm). Polymorph analysis showed that SF and SS had a type-C and B-type, respectively. SF did not have pasting temperature due to the presence of lipid, protein, and polyphenol. Washing of the flour with water decreased protein, lipid and ash contents. It resulted in a decrease in yield about 1.8 times. SS has a pasting temperature of about 71.55°C. Paste viscosity reached a maximum of about 5707 cps. In conclusion, SS that had high viscosity may be used as a thickener and SF may be used for a source of the modified starch to produce such as dextrin and glucose syrup.

Modification of flour was carried out to improve the functional properties of starch and to expand the use of starch in food products. Local red varieties of sorghum (Sorghum bicolor L.) were modified by spontaneous fermentation to increase protein digestibility and carbohydrate digestibility. In this study, 2 stages were carried out, i.e. natural sorghum flour (TSA), and spontaneously fermented sorghum flour (TSFS) with 3 levels of fermentation times (12, 48, and 72 hours TSFS). The purpose of this study was to determine the physicochemical characteristics of local red sorghum flour using the spontaneous fermentation method. The resulting product was observed for amylose content, tannin content, color, and amylograph profile with a rapid visco analyzer (RVA). The results showed that the fermentation conditions with 72 hours of TSFS increased the highest amylose content (6.43% wb) followed by the greatest change in the amylograph profile of the peak viscosity (2621 cP) compared to the 12 hours of TSFS and 48 hours of TFSF. This correlated positively with a significant decrease in tannin content in the 72-hour TSFS treatment (7.53 mg as.tannat/g). The tannin content lost by this method reached 60% of sorghum flour without treatment (16.69 mg as.tannat/g). However, in the analysis of the brightness level of sorghum flour, it was shown that the brightest color was obtained in the 48 h TSFS treatment. Modification of sorghum flour by spontaneous fermentation (using aquades immersion) can increase starch degradation and effectively improve the physicochemical properties of local varieties of red sorghum flour. Keywords: fermentation, flour, modification, sorghum

This research aimed to modify a starch obtained from palm oil production waste to produce dextrin through steam explosion (SE). The SE process was performed at different temperatures (120, 130, 140, 150, and 160 °C), and the physicochemical characteristics of the dextrin products – including the dextrin solubility, moisture content, and ash content – were analyzed. Besides, SEM image, XRD profile, FTIR profile, DSC profile, dextrose equivalent (DE) and molecular weights (MWs) were examined. The results showed that the SE process at 120 °C gave the best characteristics of dextrin, which was comparable to the commercial dextrin (CD). This dextrin had the best solubility among other products. The SEM image showed that the starch completely hydrolyzed into dextrin after SE treatment, and the dextrin crystal was mostly in irregular form. The XRD profile of the dextrin exhibited the same diffractogram patterns with a peak at 2-theta = 19.4. The FTIR profiles of the products exhibited main peaks at 1148, 1077, 994, and 928 cm–1, which were almost similar to the CD. The transition enthalpy (ΔH) of the dextrin (8.59 J/g) was greater than that of the CD (6.18 J/g), exhibiting a better hydrolysis process on the starch. Among the temperature treatments, the highest DE value was obtained for the SE treatment at 120 °C (10.33), which was still less than that of CD (18.46). The MW of the product was 102000 g/mol, which was higher than that of CD (44000 g/mol).