Utilization of waste spent coffee grounds (SCG) remains limited and requires pre-treatment before being discarded to avoid pollution to the environment. Lipids contained in SCG could be converted to biodiesel through an in situ transesterification method. Current in situ transesterification of wet SCG biomass, conducted at high reaction temperature to reduce the water effect and reduce reaction time, is energy intensive. A new approach, which combines simultaneous extraction-transesterification in a single step using soxhlet apparatus, was developed to produce biodiesel directly from wet SCG biomass. A homogeneous base catalyst at a concentration of 0.75 M showed better catalytic activity than acid, with hexane as a co-solvent on fatty acid (FA) extraction efficiency and FA to fatty acid methyl ester (FAME) conversion efficiency. Studying the factorial effect of ratio of methanol to hexane and reaction time led to the highest FA to FAME conversion efficiency of 97% at a ratio of 1 : 2 and 30 min reaction time. In addition, the catalyst could be used five times without losing its activity. In term of energy consumption, the reactive extraction soxhlet (RES) method could save 38-99% of energy compared to existing methods.

The using of carboxymethyl cellulose (CMC) from palm midrib as stabilizer on ice-cream making is done in three steps. First step is isolation process of á-cellulose from palm midrib powder, FTIR analysis shows that the compound is a cellulose molecule. The second step is alkalization with isopropanol as the solvent, carboxymethylation with monochloroacetic acid, and neutralization with CH 3 COOH 90% then ethanol, methanol and aquadest are used for purification followed with centrifugation process and adding in acetone which gives carboxymethyl cellulose a positive result in qualitative analysis. FTIR peak obtained is similar to that of commercial CMC, with the degree of substitution 0.82 and viscosity 0.076 ml/g. The last step is ice cream making process. In this step, CMC is added into the ice-cream batter with variated concentration of CMC starting from 0 to 0.5%. Ice-cream produced is then given melting time test and the overrun value is determined. Based on the research, 0.5% addition of CMC shows the most optimum melting time which is 31.02 minutes and overrun value of 42.34%. Organoleptic test given to 15 respondents also show that ice-cream with addition of 0.5% CMC gives the best result for the soft texture, sweet taste, fragrance aroma and light brown colour. CMC for thickening agent in syrup is measured with Ostwald viscometer. It shows that syrup is thicker with the addition of CMC. The highest vitamin-C content in passion fruit syrup is in addition of 0.3% which is 330.20.

Cellulose and chitosan are natural polymers that have been used as biocomposite. The aim of this research is to obtain biofilms from chitosan and oxidized cellulose crosslinks. This research is divided into three steps, i.e., isolation of cellulose from oil palm trunk and oxidation of cellulose using NaIO4 (0.2; 0.4; 0.6; 0.8; 1.0 mg/mL) to obtain dialdehyde cellulose (DAC), crosslink of oxidized cellulose with chitosan (DD = 72.85%) to obtain biofilm of chitosan/DAC (CDAC), and characterization of biofilms. The crosslinked reaction was confirmed by FT-IR analysis that showed the spectrum of Schiff base C=N group at 1651 cm–1. Tensile strength increased gradually when the NaIO4 concentration used was 0.2–0.6 mg/mL, but after those concentrations, the tensile strength slightly decreased. The morphology analysis showed that CDAC had smoother morphology than DAC, which was shown rough and showed some particle indicated the presence of unreacted cellulose. CDAC biofilms that prepared with 1.0 mg/mL NaIO4 showed the greatest antibacterial activity.

Gracilaria sp. is well known as one kind of species of red algae. The major component of polysaccharide in this alga is agar that mostly used for making thin film. In this study, the Gracilaria sp.-based thin film had been prepared using two plasticizers (glycerol and sorbitol, 0.1, 0.2, and 0.3 wt %), and chitosan (1, 2, and 3 wt %). The FT-IR analysis confirmed the interaction that happened among the component of the mixture of Gracilaria sp., plasticizers, and chitosan was based on hydrogen bonding due to the presence of -OH and -NH2 groups. The plasticizers and chitosan concentration have significant role to the mechanical properties of Gracilaria sp.-based thin film. The optimum concentration of plasticizers and chitosan based on mechanical testing result was found at 0.2 and 3.0 wt %, respectively. At those concentrations, the thin film that prepared with sorbitol showed the highest mechanical properties. Other characterizations, i.e. TGA (Thermogravimetric Analysis), SEM (Scanning Electron Microscopy), and WVP (Water Vapor Permeability) also brought the same result. The antimicrobial properties of the as prepared thin film in the presence of chitosan on agar medium and as a packaging on selected bread showed the Gracilaria sp.-based thin films was able to inhibit the growth of microbes. This antimicrobial activity can be used to declare the potential of Gracilaria sp.-based thin film as a new active food packaging.