Physicochemical characterization of resistant starch type V (RS5) from manggu cassava starch (Manihot esculenta)

Resistant starch has been well known to have beneficial health effects, mainly for digestive tracts. Starch isolated from cassava showed characteristics required to produce resistant starch type 5 (RS5). In this study, we modified tapioca starch through the gelatinization process with the addition of palm oil, coconut oil, stearic acid and lauric acid with 3 treatments, i.e. concentration (1) 10%, (2) 20% and (3) 30%. The result of study showed that modification of starch can decrease starch digestibility, increase levels of resistant starch and lower amylose levels. The analysis using X-Ray diffraction, strearic acid 30% had the peak at 7.5°, 22° and 24°. Peak 7.5° was a amylose-lipid complex as RS5. The profile of starch gelatinization using Rapid Visco Analyzer (RVA) showed that the addition of fatty acid can decrease the value of breakdown, setback, and peak viscosity. These results indicates modification of tapioca starch with fatty acid (stearic acid or lauric acid) can form amylose-lipid complex (RS5).

Effect of acetylation treatment on surface modified tapioca starches

Surface modified tapioca starch was developed by enzyme treatment (using STARGEN™ 002 enzyme) and alcohol-enzyme treatment. The effects of acetylation treatment on surface modified tapioca starches were evaluated for acetyl content (Ac%), degree of substitution (DS), morphology using scanning electron microscopy (SEM), Fourier Transform Infrared spectroscopy (FTIR), thermal properties, and X-ray diffraction (XRD) patterns. After acetylation treatment, Ac% and DS value of the samples were significantly increased for acetylated (0.67% and 0.03), enzyme-acetylated (1.13% and 0.04), and alcohol-enzyme acetylated (1.76% and 0.07). The acetylation treatment led to the formation of a few starch granules due to the introduction of hydrophilic groups of acetyl molecules into starch granules. The incorporation of acetyl groups into starch molecules also was shown at peak 1750 cm-1 , 1369 cm-1 , and 1230 cm-1 in the FTIR spectra. The enzyme-acetylated and alcohol-enzyme acetylated starch granules retained the A-type crystalline structure with decreased in the gelatinization enthalpy (ΔH) after acetylation.

Surface Treatment of Carbon Nanotubes Using Modified Tapioca Starch for Improved Force Detection Consistency in Smart Cementitious Materials

The remarkable mechanical properties and piezo-responses of carbon nanotubes (CNT) makes this group of nanomaterials an ideal candidate for use in smart cementitious materials to monitor forces and the corresponding structural health conditions of civil structures. However, the inconsistency in measurements is the major challenge of CNT-enabled smart cementitious materials to be widely applied for force detection. In this study, the modified tapioca starch co-polymer is introduced to surface treat the CNTs for a better dispersion of CNTs; thus, to reduce the inconsistency of force measurements of the CNTs modified smart cementitious materials. Cement mortar with bare (unmodified) CNTs (direct mixing method) and surfactant surface treated CNTs using sodium dodecyl benzenesulfonate (NaDDBS) were used as the control. The experimental results showed that when compared with samples made from bare CNTs, the samples made by modified tapioca starch co-polymer coated CNTs (CCNTs) showed higher dynamic load induced piezo-responses with significantly improved consistency and less hysteresis in the cementitious materials. When compared with the samples prepared with the surfactant method, the samples made by the developed CCNTs showed slightly increased force detection sensitivity with significantly improved consistency in piezo-response and only minor hysteresis, indicating enhanced dispersion effectiveness. The new CNT surface coating method can be scaled up easily to cater the potential industry needs for future wide application of smart cementitious materials.

Karakterisasi Fisik Pati Tapioka Modifikasi Gabungan Hidroksipropilasi dengan Fosfat-Ikat Silang

Native tapioca starch has limited application in food industry due to its physicochemical characteristics that are not suitable for processing conditions, such as unstable at high temperature heating, acidic conditions, stirring, and undergoing syneresis. This deficiency can be overcome by applying a dual modification involving hydroxypropylation and cross-linking with phosphates. In this study, modification was carried out by hydroxypropylation using propylene oxide (8, 10, and 12%), followed by cross-linking with a combination of sodium tripolyphosphate (STPP) and sodium phosphate (STMP) with a ratio of 2%: 5%. The modified tapioca starch had water content of 7.82-8.19% with a pH value of 7.04-7.26, and phosphorus resiude of <0.4%. There were no change in starch granules and type of cristallline (A-tyype) of starch modifications. The dual modified starch with the addition of 10% propylene oxide concentration with a mixture of STMP : STTP ratio (2%:5% was selected to have acceptable physicochemical properties. It showed lowered pasting temperature, minimum break down viscosity, increased peak and setback viscosity compared to that of native starch. The modified tapioca starch also showed more heat stable and stirring resistant than that of native tapioca starch.