No abstract

This study was undertaken to compare the chemical properties and yields of pineapple leaf residue (PLR) char produced by field burning (CF) with that produced by a partial combustion of air-dried PLR at 340 °C for 3 h in a furnace (CL). Higher total C, lignin content, and yield from CL as well as the presence of aromatic compounds in the Fourier Transform Infrared spectra of the char produced from CL suggest that the CL process was better in sequestering C than was the CF process. Although the C/N ratio of char produced from CL was low indicating a high N content of the char, the C in the char produced from CL was dominated by lignin suggesting that the decomposition of char produced from CL would be slow. To sequester C by char application, the PLR should be combusted in a controlled process rather than by burning in the field.

The aim of this study was to compare the antioxidant capacity and total phenolic content as well as the chemical groups of fresh, oven-dried and stir-fried tamarind (Tamarindus indica L.) leaves. Methanol was used for extraction of fresh, oven-dried and stir-fried tamarind leaves. The stir-fried leaves were prepared using medium heat for 10 minutes prior to extraction and chemical analysis while dried leaves were obtained by oven drying at 60°C for 3 hours. The stir-fried leaves had significantly highest total phenolic content (TPC) (139.87 mg/g) and percentage DPPH radical-scavenging inhibition (69.92%) while the fresh leaves had the lowest TPC (39.31 mg/g) and antioxidant capacity (16.46%). The FTIR spectral data suggest that the heat treatment increased the amine groups as well as the antioxidant capacity of the tamarind leaves. To increase the antioxidant capacity, the tamarind leaves should be prepared in a stir-frying process.

This work aims to determine antioxidant, total phenolic content and Fourier transform infrared spectroscopy (FTIR) analysis of breadfruit leaves which are essential in management of diabetes. The methanolic extracts of breadfruit leaves was used to analyze for total phenolic content and antioxidant. Total phenolic content of the extracts was measured using the Folin–Ciocalteu assay while the antioxidant activity of plant extracts was measured by the 1, 1-diphenyl-2-picryhyradrazyl (DPPH) radical scavenging assay. FTIR analysis was used to determine the chemical components in the leaves. Total phenolic content in fresh breadfruit leaves (144.16 mg/g ± 17.98) was comparable to those of green tea. The results showed the breadfruit leaves extracts exhibited potent antioxidant activity. The presence of OH group also suggests antioxidant capacity of breadfruit leaves to deactivate free radicals as glucose itself could react with hydrogen peroxide in the presence of iron and copper ions to form hydroxyl radical.

Problem Statement: Tropical rainforests cover about 19.37 million ha (60%) of Malaysia's total area and about 8.71 million ha can be found in Sarawak, Malaysia. Excessive logging, mining and shifting cultivation contribute to deforestation in Sarawak. The objectives of this study were to: (i) Quantify soil Organic Matter (SOM), Soil Organic Carbon (SOC) and Humic Acids (HA) in rehabilitated and secondary forest soils and (ii) Compare SOM, SOC and HA sequestrations of both forests. Approach: Soil samples were collected from a 16 year old rehabilitated forest and a secondary forest at Universiti Putra Malaysia, Bintulu Campus. Fifteen samples were taken at random with a soil auger at 0-20 cm and 20-40 cm depths. The bulk densities at these depths were determined by the coring method. The bulk density method was used to quantify the total C (TC), Total Organic Carbon (TOC), Organic Matter (OM), Humic Acids (HA) and total N at the stated sampling depths. Results: Regardless of forest soil type and depth, the amount of SOM of the two forests was similar. Except for 20-40 cm of the secondary forest soil whereby the quantity of total C sequestered was significantly lower than that of the rehabilitated forest soil, C sequestration was similar irrespective of forest type and depth. Nevertheless, stable C (organic carbon) sequestered in HA was generally higher in the rehabilitated forest soil compared with the secondary forest soil. This was attributed to higher yield of HA in the rehabilitated forest soil partly due to better humification at 20-40 cm in the rehabilitated forest soil. Conclusion: Hence, the findings suggest that organic C in HA realistically reflects C sequestration in the soils of the two forests investigated.