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In Thailand, the roselle seeds have a few utilizations other than seeds for planting propagation. Consequently, this study aimed to evaluate the nutritional and mineral profile of roselle seeds in the Northeast region of Thailand. The obtained results proved that roselle seeds were found to be a good source of carbohydrates (41.48 ± 0.31 %), protein (30.40 ± 0.09 %), and fat (19.70 ± 0.04 %). Additionally, the results indicated that roselle seeds were a rich source of fiber (40.61 ± 0.26 %) and had a high energy content (1945.03 ± 12.31 KJ/100 g of sample).  The macronutrients and micronutrients of the roselle seeds, such as K, P, Mg, Zn, Fe, Mn, and Cu, were found to be 2092.50 ± 1.89, 891.22 ± 3.71, 366.00 ± 1.34, 7.17 ± 0.13, 6.81 ± 0.20, 5.88 ± 0.14 and 4.22 ± 0.11 mg/g of sample, respectively. Furthermore, the total phenolic compounds as bioactive components and DPPH radical scavenging capacity were equal to 21.22 ± 0.24 mg GAE/100 g of sample and 46.28 ± 1.35 %, respectively. Thus, the roselle seeds were considered a cheap nutrient source and could be a good source of potential food ingredients. HIGHLIGHTS The roselle (Hibiscus sabdariffa) seeds derived from Roi Et Province in the Northeast region of Thailand have a highly rich source of nutrients, bioactive compounds, and minerals The roselle seeds were considered a cheap nutrient source and could be a good source of potential food ingredients GRAPHICAL ABSTRACT

The objective of this study was to determine the nutritional value, total phenolic and flavonoid contents, and antioxidant activities of the roasted broken brown rice powder. The roasted broken brown rice powder was dried at 60 °C for 3 h in a hot air oven and extracted with absolute ethanol by using ultrasonic technique. Then, the sample was filtered to separate the residue and mixture solution and dried to remove the solvent by rotary evaporator for obtaining the ethanolic crude extract. Finally, the crude extract was collected and determined proximate composition, total phenolic content (TPC), total flavonoid content (TFC), and antioxidant capacity. The results revealed that the percentage crude extract of the extraction yield was 0.47% by weight with crude carbohydrate (74.47% w w−1), crude protein (8.11% w w−1), and fat (0.05% w w−1), respectively. The TPC and TFC were found at an average of 20.40 ± 0.37 mg GAE g−1 crude extract and 4.58 ± 0.19 mg QE g−1 crude extract, respectively. Moreover, the sample has highly efficient antioxidants activity similar to a standard Trolox solution. Therefore, it was reasonably concluded that the roasted broken brown rice powder product was rich in beneficial nutrients for the health effects and represented adding value to a by–product of rice production.

In the present work, the catalytic activity and stability of the Fresh-water Clamshells-derived CaO catalyst were investigated by the transesterification reaction of lard oil. The physicochemical properties of lard oil as a raw material for biodiesel production compared with palm oil were also studied. The obtained CaO_FWC was characterized by various analytical techniques to evaluate the physicochemical properties consisting of TGA, SEM, XRD, XRF, BET surface area, FT-IR, Hammett indicator method, and CO2-TPD. The results found that the fresh CaO_FWC showed the specific surface area, percentage of Ca element, total basic site, and basic strength of 8.293 m2g−1, 98.6 wt.%, 8.450 mmol g−1, and 15 < H_< 18.4, respectively which similar to CaO commercial grade. In addition, the fresh CaO_FWC catalyst also presented high catalytic activity that gave %FAME of lard oil more than 96.5 %. However, the CaO_FWC catalyst could only reuse 3 times with the catalytic activity slightly decreased, and %FAME remained higher than 95 %. While the stability of the CaO_FWC catalyst was tested by storage for a long time to 180 days, this experimental data suggested that the CaO_FWC catalyst could preserve for only 30 days, with the catalytic efficiency remaining similar to the fresh CaO_FWC. Furthermore, the preservation and reusability of the catalyst were also studied in terms of the kinetic rate of reaction for use as a database to optimize the reaction conditions. Finally, the fuel properties of biodiesel products derived from lard oil and palm oil as raw materials and catalyzed by CaO_FWC catalyst met the specified standards both of EN-14214 and ASTM-D6751. Therefore, all the results of this work were excellent databases for utilizing and adding value to the Fresh-water Clamshells and lard oil as biomass sources for further development and development as renewable and alternative energy in Thailand. HIGHLIGHTS The CaO catalyst obtained after calcination of the Fresh-water Clamshells has displayed excellent catalytic activity for the transesterification of lard oil with biodiesel conversion and FAME yield obtained under optimal conditions up to 96.86 % The Fresh-water Clamshells could stand promising resource for low-cost catalysts to lead the way for low-cost biodiesel The kinetic data can be used to optimize the biodiesel production process GRAPHICAL ABSTRACT