Changes to the physicochemical properties of wheat, sago and tapioca starches subjected to gamma ray, electron beam and microwave irradiations and the conditions that lead to wheat starch having leaching behaviour similar to sago or tapioca starch were studied. The properties were characterised through swelling and leaching behaviours of the starch granules and retrogradation following pasting. The leaching of wheat starch increased tremendously and resulted in amylose to amylopectin ratios in the leachate similar to that of native sago and tapioca starches. This observation is significant as wheat starch is known to have a leachate composition of mostly amylose. This opens up the possibility of utilising wheat starch in snacks where tapioca and sago starch are commonly used. It was observed that the required conditions for such changes were exposure to microwave for 8 and 10 minutes, electron beam at 5 and 10 kGy and gamma ray at 5 kGy.
The impacts on both rheological parameters; Casson yield stress and Casson viscosity were determined. The interactions among blend’s components; xanthan gum (XG), corn starch (CS), glycerin (GL) and their relationship with both flow parameters were also investigated by using D-Optimal mixture design. Three levels of cocoa butter substitution assigned in chocolate production were at 5%, 10% and 15% level with random proportions of each component generated by Design Expert software. An appropriate mathematical model was applied to evaluate each response as a function of the proportions of the components enabling in prediction of future response by using any blend of components. As the incorporation of the blends (XG/CS/GL) in chocolate production was elevated from 5% to 15%, both parameters; viscosity and yield stress of chocolate were gradually increased, as in range 7.819 to 10.529 Pa, and 2.372 to 3.727 Pa.s, respectively. Neither binary nor ternary component-component interaction exhibited synergistic effect. Nevertheless, strongest antagonistic effect on both rheological parameters of substituted chocolate at 5% level and 10% level were respectively observed at ternary interaction region for the former, and at binary interaction area of CS:GL, closer to CS corner as for the latter. This study somehow provides ideas on how component-component interactions influence experimented response.
Starch is a biodegradable polymer produced in abundance from many renewable resources. This study examined the influence of citric acid (0-40% w/wt%) ) and water (0-40% w/wt%) as secondary additive and glycerol as plasticizer on the mechanical properties of bio-plastic starch (BPS) from Malaysian sago. The CA content varies from 0 to 40 w/wt% while water was also varied from 0 to 40 w/wt%. FT-IR spectroscopy showed that acid citric improve the properties of BPS and water give negative effects to the carbon hydrogenbond. It is obvious that the addition of the CA at 30 wt/wt% improve the mechanical property of BPS to more than 40% compare to the addition of water.
This study was carried out to determine the proximate, functional and pasting properties of breadfruit starch. Breadfruit starch was isolated from matured breadfruit (Artocarpus altilis) and was analyzed for its fuctional, proximate and pasting properties. The starch contains 10.83%, 0.53%, 0.39%, 22.52%, 77.48% and 1.77% moisture, crude protein, fat, amylose, amylopectin and ash contents respectively. The average particle size, pH, bulk density and dispersibility of the breadfruit starch were 18 μm, 6.5, 0.673 g/mls, and 40.67% respectively. The swelling power of the breadfruit starch increases with increase in temperature, but there was a rapid increase in the swelling power from 70 to 80 0C. The pasting temperature of the starch paste was 84.05 0C, setback and breakdown values were 40.08 and 7.92 RVU respectively. The peak viscosity value was 121.25 RVU while final viscosity value was 153.42 RVU. This study concluded that breadfruit starch has an array of functional, pasting and proximate properties that can facilitate its use in so many areas where the properties of other starches are acceptable.
The native sago starch exists as a compact crystalline structure and is not efficiently hydrolyzed by Raw Starch Degrading Enzyme (RSDE). In order to enhance its hydrolysability, the starch was treated with acid and heated below its gelatinization temperature, thus increasing the accessibility of the sago starch granule to enzymatic attack. Results showed that treatment of sago starch with acid at pH 2.0 and temperature 65oC for 2 hours greatly enhanced its conversion rate to glucose from 53.3% to 71.9%. It is clearly shown that high yield of glucose is produced during hydrolysis of acid-treated sago starch using the Raw Starch Degrading Enzyme from Acremonium sp. The difference between the acid-treated and untreated sago starch in this study could be due to the differences on the surface of the sago starch granule which may influence the accessibility and diffusion of enzyme into the starch during hydrolysis.
Tapioca starch, poly(lactic acid) and Cloisite 10A nanocomposite foams were prepared by twin screw extrusion. Residence time distribution (RTD) in an extruder is a useful means of determining optimal processing conditions for mixing, cooking and shearing reactions during the process. RTD was obtained by inputting a pulse-like stimulus and measuring its profile at the exit or other point in the extruder. During processing, after the steady state had been reached, a fixed amount of tracer was instantaneously fed into the extruder and its concentration was measured from the samples collected at fixed time intervals in the extruder exit. The tracer concentration was the value of the redness, a* was used as a measure of red colour intensity of the concentration of tracer in the extrudate. Meanwhile, the effects of two screw configurations (compression and mixing screws) and two barrel temperatures (150 and 160ºC) on RTD of nanocomposite foams were also studied. The influences of screw configurations and barrel temperatures on RTD were analyzed using the mean residence time (MRT) and variance. Screw configurations and temperatures had significant effects (P
Linear density polyethylene (LDPE)/thermoplastic sago starch (TPSS), blended with and without the addition of compatibilizer [Polyethylene-grafted-Maleic Anhydride, (PE-g-MA)] were prepared for soil burial test. The test was conducted in the natural soil environment for 3 and 6 months. Different loading of TPSS (10, 20, 30, 40, and 50 wt. %) were used in this study. After soil burial, the blends were evaluated for their tensile properties and scanning electron microscopy (SEM) to observe the surface morphology properties after the test. For LDPE/TPSS, it was observed that the tensile strength decreased with the increase of soil burial time, as well as Young modulus and elongation at break (EB). The LDPE/TPSS/PE-g-MA also showed the same trend for the tensile properties, but with higher properties as compared to uncompatibilized blends. The tensile properties also decreased with the increase in the TPSS loading for both the LDPE/TPSS and LDPE/TPSS/PE-g-MA. Meanwhile,
the scanning electron microscopy (SEM) on the blend surfaces after the soil burial test showed that degradability increased with the increase in the exposure time as well as the TPSS loading.
This paper presents a comparison on the effects of blending chitin and/or starch with poly(lactic acid) (PLA). Three sets of composites (PLA-chitin, PLA-starch and PLA-chitin-starch) with 92%, 94%, 96% and 98% PLA by weight were prepared. The percentage weight (wt.%) amount of the chitin and starch incorporated ranges from 2% to 8%. The mechanical, dynamic mechanical, thermal and microstructural properties were analyzed. The results from the tensile strength, yield strength, Young's modulus, and impact showed that the PLA-chitin-starch blend has the best mechanical properties compared to PLA-chitin and PLA-starch blends. The dynamic mechanical analysis result shows a better damping property for PLA-chitin than PLA-chitin-starch and PLA-starch. On the other hand, the thermal property analysis from thermogravimetry analysis (TGA) shows no significant improvement in a specific order, but the glass transition temperature of the composite increased compared to that of neat PLA. However, the degradation process was found to start with PLA-chitin for all composites, which suggests an improvement in PLA degradation. Significantly, the morphological analysis revealed a uniform mix with an obvious blend network in the three composites. Interestingly, the network was more significant in the PLA-chitin-starch blend, which may be responsible for its significantly enhanced mechanical properties compared with PLA-chitin and PLA-starch samples.
Synthetic plastics are severely detrimental to the environment because non-biodegradable plastics do not degrade for hundreds of years. Nowadays, these plastics are very commonly used for food packaging. To overcome this problem, food packaging materials should be substituted with "green" or environmentally friendly materials, normally in the form of natural fiber reinforced biopolymer composites. Thermoplastic starch (TPS), polylactic acid (PLA) and polybutylene succinate (PBS) were chosen for the substitution, because of their availability, biodegradability, and good food contact properties. Plasticizer (glycerol) was used to modify the starch, such as TPS under a heating condition, which improved its processability. TPS films are sensitive to moisture and their mechanical properties are generally not suitable for food packaging if used alone, while PLA and PBS have a low oxygen barrier but good mechanical properties and processability. In general, TPS, PLA, and PBS need to be modified for food packaging requirements. Natural fibers are often incorporated as reinforcements into TPS, PLA, and PBS to overcome their weaknesses. Natural fibers are normally used in the form of fibers, fillers, celluloses, and nanocelluloses, but the focus of this paper is on nanocellulose. Nanocellulose reinforced polymer composites demonstrate an improvement in mechanical, barrier, and thermal properties. The addition of compatibilizer as a coupling agent promotes a fine dispersion of nanocelluloses in polymer. Additionally, nanocellulose and TPS are also mixed with PLA and PBS because they are costly, despite having commendable properties. Starch and natural fibers are utilized as fillers because they are abundant, cheap and biodegradable.
Starch-based hydrogels are promising smart materials for biomedical and pharmaceutical applications, which offer exciting perspectives in biophysical research at molecular level. This work was intended to develop, characterize and explore the properties of hydrogel from starch extracted from new source, Dioscorea hispida Dennst. Starch-mediated hydrogels were successfully synthesized via free radical polymerization method with varying concentrations of acrylic acid (AA),N,N'-methylenebisacrylamide (MBA) and sodium hydroxide (NaOH) in aqueous system. The grafting reaction between starch and AA was examined by observing the decline in intensity peak of hydrogel FTIR spectrum at 3291cm-1 and peak around 1600-1680cm-1, indicating the stretching of hydroxyl group (OH) and stretching of carbon-carbon double bond (CC) respectively. The effects of cross-linker, monomer and NaOH concentration on swelling ratio and gel content in different medium and conditions were also evaluated. The thermal stability and structural morphology of as-synthesized hydrogels were studied by thermogravimetry analysis (TGA) and scanning electron microscopy (SEM). In-vitro cytotoxicity study using small intestine cell line (FHS-74 Int) revealed that the as-formulated eco-friendly-hydrogel was free from any harmful material and safe to use for future product development.
The advancements in material science and technology have made polyurethane (PU) one of the most important renewable polymers. Enhancing the physio-chemical and mechanical properties of PU has become the theme of this and many other studies. One of these enhancements was carried out by adding starch to PU to form new renewable materials called polyurethane-starch composites (PUS). In this study, PUS composites are prepared by adding starch at 0.5, 1.0, 1.5, and 2.0 wt.% to a PU matrix. The mechanical, thermal, and morphological properties of PU and PUS composites were investigated. Scanning electron microscope (SEM) images of PU and PUS fractured surfaces show cracks and agglomeration in PUS at 1.5 wt.% starch. The thermo-mechanical properties of the PUS composites were improved as starch content increased to 1.5 wt.% and declined by more starch loading. Despite this reduction, the mechanical properties were still better than that of neat PU. The mechanical strength increased as starch content increased to 1.5 wt.%. The tensile, flexural, and impact strengths of the PUS composites were found to be 9.62 MPa, 126.04 MPa, and 12.87 × 10(-3) J/mm², respectively, at 1.5 wt.% starch. Thermal studies showed that the thermal stability and crystallization temperature of the PUS composites increased compared to that of PU. The loss modulus curves showed that neat PU crystallizes at 124 °C and at 127 °C for PUS-0.5 wt.% and rises with increasing loading from 0.5 to 2 wt.%.
Two different ionic liquid-based biopolymer electrolyte systems were prepared using a solution casting technique. Corn starch and lithium hexafluorophosphate (LiPF₆) were employed as polymer and salt, respectively. Additionally, two different counteranions of ionic liquids, viz. 1-butyl-3-methylimidazolium hexafluorophosphate (BmImPF₆) and 1-butyl-3-methylimidazolium trifluoromethanesulfonate (also known as 1-butyl-3-methylimidazolium triflate) (BmImTf) were used and studied in this present work. The maximum ionic conductivities of (1.47 ± 0.02) × 10(-4) and (3.21 ± 0.01) × 10(-4) S∙cm(-1) were achieved with adulteration of 50 wt% of BmImPF₆ and 80 wt% of BmImTf, respectively at ambient temperature. Activated carbon-based electrodes were prepared and used in supercapacitor fabrication. Supercapacitors were then assembled using the most conducting polymer electrolyte from each system. The electrochemical properties of the supercapacitors were then analyzed. The supercapacitor containing the triflate-based biopolymer electrolyte depicted a higher specific capacitance with a wider electrochemical stability window compared to that of the hexafluorophosphate system.
In this work, polymer electrolytes have been prepared by doping starch with Sodium Phosphate (Na3PO4). The incorporation of 25% Na3PO4 optimizes the room temperature conductivity of the electrolyte at 7.27 x 10-6 Scm-1. The temperature dependence of conductivity for the electrolyte is Arrhenius and the activation energy, Ea, of 75% corn starch-25% Na3PO4 electrolyte is 0.26eV. The dielectric studies reveal the non-Debye nature of the electrolyte. The complexation of Na3PO4 with the polymer host was studied using Fourier transform infrared (FTIR) spectroscopy.
The aim of this study was to evaluate the effect of barrel temperature and flour types on the residence time and physical properties of various flour extrudates. Corn flour, rice flour, corn flour with potato starch (30% w/w, d.b), and rice flour with potato starch (30%w/w, d.b) were extruded at screw speed of 75rpm, feed moisture at 25% (w/w, w.b.), barrel temperature ranging from 80°C to 140°C and die size of 1.88mm. The extrudates were dried at 50°C overnight and further analysed. Results showed that an increase in extruder barrel temperature decreased the residence time of the flours in the extruder (from 4.11-11.32min to 2.24-6.76min), but increased the expansion ratio, rehydration ratio, water absorption index, water solubility index and b value of the extrudate (p≤0.05). The extrudates had the mean residence time and physical properties of rice flour
Coating fertilizer particles with thin films is a possibility to control fertilizer release rates. It is observed that novel urea cross-linked starch-lignin composite thin films, prepared by solution casting, swell on coming into contact with water due to the increase in volume by water uptake by diffusion. The effect of lignin content, varied from 0% to 20% in steps of 5% at three different temperatures (25°C, 35°C and 45°C), on swelling of the film was investigated. By gravimetric analysis, the equilibrium water uptake and diffusion coefficient decrease with lignin content, indicating that the addition of lignin increases the hydrophobicity of the films. When temperature increases, the diffusion coefficient and the amount of water absorbed tend to increase. Assuming that swelling of the thin film is by water uptake by diffusion, the diffusion coefficient is estimated. The estimated diffusion coefficient decreases from 4.3 to 2.1 × 10-7 cm2/s at 25°C, from 5.3 to 2.9 × 10-7 cm2/s at 35°C and from 6.2 to 3.8 × 10-7 cm2/s at 45°C depending on the lignin content. Activation energy for the increase in diffusion coefficient with temperature is observed to be 16.55 kJ/mol. An empirical model of water uptake as a function of percentage of lignin and temperature was also developed based on Fick's law.
Starch and hydrocolloids were often used together in food industry to modify the rheological properties with the aim to enhance the starch tolerance to processing conditions. As such, the rheological properties of xanthan gum (XG), carrageenan, high (HMP) and low methoxyl pectin (LMP), with native corn starch (NCS) and modified corn starch (MCS) at different temperature were evaluated in this study. The flow behavior index (n) of corn starch-hydrocolloid mixtures were observed in the range from 0.160 to 0.604 where indicated the shear thinning behavior. The addition of hydrocolloids increased the apparent viscosity of the starch system. NCS mixtures showed consistency index (K) and apparent viscosities (na,100) decreased with increase in the temperature. The addition of XG and carrageenan increased the storage (G’) and loss (G”) moduli. Among the hydrocolloids, the XG addition to the NCS exhibited superior viscoelastic properties as evidenced by the highest G’ and lowest tan δ values. XG was observed capable to increase while pectin reduced the solid-like starch system. This result provides pragmatic data for food engineer in process design and food product development by minimizing the cost of trial and error.
This study investigated the behavior and mechanisms of cross-linked Durio zibethinus seed starch (CDSS) flocculants for landfill leachate treatment. A physical-chemical treatment method of coagulation-flocculation process and starch modification were implemented in treating stabilized leachate from Matang Landfill, Perak, Malaysia. In practical, the removal performance of color, COD, suspended solid and turbidity for CDSS flocculants were evaluated by combining with primary coagulant of polyaluminium chloride (PAC). In this study, the application of crosslinking modification for Durio zibethinus seed waste starch flocculants showed good improvement. The impurities removal for colour, COD, suspended solid and turbidity were increased by the addition of CDSS flocculants. Furthermore, the average size of the floc was also increased from 60.24 µm to 89.5 µm. Despite, the addition of CDSS flocculants produced a reduction of PAC coagulant from 2700 mg/L to 2200 mg/L, with 500 mg/L reduction on the PAC dosage dependency. Therefore, these results affirmed the potentials of crosslinked modification for Durio zibethinus seed waste starch flocculants in landfill leachate treatment.
To study the wound healing efficacy of breadfruit starch hydrolysate, an in vitro wound scratch assay was conducted, in which the migration rate of wounded NIH 3T3 fibroblasts was determined. Wounds treated with lower dextrose equivalent (DE), (DE 10-14) starch hydrolysate were found capable to improve the wound healing of NIH 3T3 fibroblast cell with the percentage of wound closure improvement of 77%, respectively when compared with higher DE range (DE 15-19 and DE 20-24). The findings obtained in the BrdU uptake and MTT viability assays confirmed the wound healing properties of breadfruit starch hydrolysate as the starch hydrolysate-treated wounded NIH 3T3 fibroblasts were able to proliferate well and no cytotoxicity was observed. Together, these findings indicated that the newly developed breadfruit starch hydrolysate performed better than commercial (COM) starch hydrolysate of the same DE ranges. In conclusion, breadfruit starch hydrolysate had better functional properties than did starch hydrolysates derived from other sources and that they could play a beneficial role in wound healing applications.
Starch biopolymer films incorporated with chitosan nanoparticles (CNP) or starch/CNP films are promising alternatives to non-degradable food packaging materials. The films can be utilized for active food packaging applications because CNP exhibits antimicrobial and antioxidant properties, which can improve food shelf-life. Nonetheless, knowledge of the effects of CNP inclusion on the properties of starch films is not fully elucidated. This paper reviews the influences of various concentrations of CNP, sizes of CNP, and other additives on the mechanical, thermal, barrier, antimicrobial, antioxidant, biodegradability, and cytotoxicity properties of starch/CNP films as well as the mechanisms involved in relation to food packaging applications. The usage of starch/CNP films for active food packaging can help to reduce environmental issues and contribute to food safety and security.
Nutrient leaching and volatilization cause environmental pollution, thus the pursuit of developing controlled-release fertilizer formulation is necessary. Biochar-based fertilizer exhibits slow-release characteristic, however the nutrient release mechanism needs to be improved. To overcome this limitation, the approach of applying encapsulation technology with biochar-based fertilizer has been implemented in this study. Black peppercorn waste was used to synthesize urea-impregnated biochar (UIB). Central composite design was used to investigate the effects of pyrolysis temperature, residence time and urea:biochar ratio on nitrogen content of UIB. The optimum condition to synthesize UIB was at 400 °C pyrolysis temperature, 120 min residence time and 0.6:1 urea:biochar ratio, which resulted in 16.07% nitrogen content. The tapioca starch/palm oil (PO) biofilm formulated using 8 g of tapioca starch and 0.12 µL of PO was coated on the UIB to produce encapsulated urea-impregnated biochar (EUIB). The UIB and EUIB pellets achieved complete release of nitrogen in water after 90 min and 330 min, respectively. The nutrient release mechanism of UIB and EUIB was best described by the Higuchi model and Korsmeyer-Peppas model, respectively. The improvement of water retention ratio of UIB and EUIB pellets was more significant in sandy-textural soil as compared to clayey-textural soil. The EUIB derived from peppercorn waste has the potential to be utilized as a sustainable controlled-release fertilizer for agriculture.