Abstract Syringodium isoetifolium was seagrass widely grown on the coast of Indonesia, and was the phytochemical source. This research was conducted to maximalize the extraction of their phytochemicals and bioactive compounds. Firstly, seagrass powder was extracted with different solvent polarities i.e. water, 50% ethanol, and 100% ethanol. Secondly, extraction was continued using different extraction techniques i.e. microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE-Bath system and UAE-Probe system), and conventional with the best solvent. Phytochemicals, bioactive compounds, antioxidant activity, and scanning electron microscope (SEM) were analyzed on the seagrass extracts. As result, the total phytochemical kind (i.e. terpene, polyphenols, alkaloid, and amino acid derivative groups) in the most dominant was had by 50% ethanol extract. Accordingly, extraction using the UAE-Probe with 50% ethanol as solvent able to obtain the richest bioactive compound, the most damaged cell microstructure, and the strongest antioxidant activity. Interestingly, quercetin was only detected dominant in UAE-Probe extract. Therefore, UAE-Probe with 50% ethanol solvent was the best method for recovering the valuable components in seagrass.

Abstract: Plant biomass is a potential lignocellulose material for the synthesis of carbon nanostructures. Its characteristics as adsorbent and its particle size make it a good additive for liquid fertilizers. In this research, we study the influence of different sequential pyrolysis methods (the hydrothermal-microwave method and the reflux-microwave method) on the characteristics of carbon nanostructures from sugarcane leaf biomass. Both the reflux and hydrothermal methods were adjusted at 200 oC, then followed by microwave treatment at 800 W. Characterization using X-ray diffraction showed that the hydrothermal - microwave method indicated the diffractogram patterns of both carbon nanostructures and cellulose. SEM micrographs show sphere and block shapes. The FTIR spectra indicates different concentrations of oxy surface functional groups. The UV spectra of the dispersed product in water indicates the presence of aromatics C=C groups. The hydrothermal-microwave method resulted the product in which lower crystalinity index of cellulose, smaller particles, lower concentration of the oxy surface groups than the reflux - microwave one. The correlation of the chemical properties (aromaticity and fraction of polar groups) was more linier than of physical - chemical properties (index of cellulose crystalinity and fraction of polar groups). The test of dispersion stability showed that qualitatively sonication gave the most transparent brown colloid and after keeping for 11 h, the sonication gave the highest TDS.

Abstract Lemon (Citrus limon B.) is one of the local fruits abundant in Indonesia. The dried lemon fruit was required for storage, extended shelf-life, minimizing decay, and simple distribution. This research applied vacuum drying to lemon slice dehydration in order to achieve quick times and preserve product quality. Vacuum drying with combinations of temperature (40, 50, 60 oC) and vacuum pressure (-38 and -69 cmHg) was applied to drying lemon slices until the final moisture content (9-11% w.b) was reached. The color, hardness value, and vitamin C content were analyzed on dried lemon slices. As a result, 60 °C with -38 cmHg indicates the fastest time to achieve a dry lemon slice and the highest hardness value. The 40 °C with -69 cmHg indicated the best vitamin C content of 76.40 (mg/100 g dw) and color value of L* (64.35 ± 0.57), H (77.0 ± 0.78), a*(6.43 ± 0.55), b*(27.92 ± 1.87), and c* (28.65 ± 1.91). The higher vacuum pressure accelerated the drying time and preserved the quality of the dried lemon slice. The higher temperatures led to the quality deterioration though also accelerate drying time. Experiment with more enhanced vacuum pressure and decreased temperature on lemon drying was required.