The research aims to investigate the difference in rice bran compositions of three major paddy varieties in Malaysia, which are MR 220 CL2, MR 219 and MR 297. The proximate compositions, antioxidative properties and fatty acid profile of the rice bran were compared. Stabilization of rice bran of all varieties was conducted in prior to the extraction of rice bran oil (RBO) by using the Soxhlet extraction. Fatty acid compositions consisted in RBO of each variety were analysed by using gas chromatography-mass spectrometry (GC-MS). Results on proximate compositions showed that MR 297 was the highest in the content of moisture (3.90 ± 0.29 %), fat (22.52 ± 0.09 %), protein (12.70 ± 0.53 %) and crude fiber (3.65 ± 0.26 %). MR 297 variety also exhibited the highest antioxidant activity, which indicated by the highest amount of total phenolic content (TPC) and ferric reducing antioxidant power (FRAP) compared to the other two varieties. Three components of fatty acids: palmitic acid; oleic acid; alinoleic acid have made up around 90% of the total fatty acids of the RBO for all varieties. The RBO also contains ideal fatty acid compositions with more unsaturated compared to saturated fatty acid, which makes it suitable to be used as a healthy edible oil. Results of this study can provide significant nutritional information for future investigations on the conversion of this agro-waste into valuable products for animals and human benefits.
Nanocellulose (NC) was isolated from an underutilized agricultural residue, defatted rice bran (DRB), obtained from three major paddy varieties in Malaysia, MARDI Rice (MR): MR 220, MR 219, and MR 297. The DRB was subjected to alkali (NaOH) and bleaching treatments prior to the isolation of NC. The NC from DRB was produced through the acid hydrolysis technique using 55%wt sulphuric acid (H2SO4) with the assistance of ultrasonication. The morphological structure of NC was analyzed through transmission electron microscopy (TEM). Based on the observation, a needle-like structure was observed for NC 219 while NC 220 and NC 297 showed nano-web structures. All obtained NC dimensions ranged from 183 to 263 nm long and 4.70 to 4.97 nm wide. Fourier transform infrared (FTIR) spectroscopy revealed the presence of all important compositions for the cellulose of each variety, indicating that the chemical structure of DRB cellulose has not been altered by acid hydrolysis. Particle size distributions portrayed a unimodal graph for NC 220 and NC 219. This comparative study provides an insight into the possibility of using DRB as a potential source of NC. The promising characteristics of NC from MR 219 allowed its application as an emulsifier for stabilizing a solid particle-based emulsion.
Defatted rice bran (DRB), an underutilized agricultural waste, was subjected to sequential pretreatment steps to isolate the cellulose from the lignocellulosic materials. Further extraction by using 55 wt % sulfuric acid combined with ultrasonication was able to produce nanocellulose (NC so ). Ultrasonication effectively reduced the particle size and increased the crystallinity of NC so compared to the control (NC cont ). Unchanged functional groups and an insignificant decrease of the degradation temperature of NC so demonstrated the negligible impact of ultrasound on the chemical structure and thermal stability of the extracted nanocellulose. Nanocellulose isolated by the described technique has potential applications as biocomposite material and emulsifier in stabilizing emulsions.
The rice bran oil (RBO) can form its semisolid spread through solvent fractionation. The rice bran oil spread (RBOS) is proposed to be included in the production of bakery products. The aim of this is study is to compare the physicochemical, textural properties and thermal properties of RBOS with commercial shortening (CS). Spreadability analysis was conducted using a texture analyzer. There was no significant difference (p > 0.05) in firmness and work of shear between CS and RBOS. The fatty acid compositions were determined through GC-MS. The major fatty acids in RBOS were palmitic acid, oleic acid and linoleic acid which is similar to those in RBO but significantly (p < 0.05) higher in saturated fatty acid content. RBO contains a high amount of γ-oryzanol and phytosterols which is beneficial in solid fat structuring. The quantitation of γ-oryzanol was performed by using UV-Vis spectrophotometer while the phytosterol content was analyzed by using HPLC. There was no significant difference (p > 0.05) in γ-oryzanol between RBO (1,299.88 ± 50.97 mg/ 100 g sample) and RBOS (1,201.86 ± 84.37 mg/ 100 g sample). However, there was a significant difference (p < 0.05) in phytosterols between CS (4.17 ± 0.26 mg/ 100 g sample), RBO (247.00 ± 0.89 mg/ 100 g sample) and RBOS (184.16 ± 0.56 mg/ 100 g sample). Besides, thermal analysis of CS and RBOS were carried out using DSC and TGA. The similar textural properties but better physicochemical properties make RBOS becomes a suitable choice as alternate shortening for bakery product.
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