Recently, the uses of dyes are increasingly widespread especially in foods and beverages as food colors to attract the consumers. The dye that currently attracts is indigo. Indigo is a group of carbonyl compounds, one of the oldest known dyes in terms of natural blue dye derived from the Indigofera tinctoria plant. The use of indigo as a natural food dye intended to reduce the use of synthetic dyes are carcinogenic impact. The method used in this study includes the analysis of indigo using UV-Vis spectrophotometry and FTIR analysis. Based on the UV-Vis Spectrophotometer analysis results with the various concentrations of 0.002 mg/mL; 0.004 mg/mL; 0.006 mg/mL and 0.008 mg/mL were obtained maximum absorption peak at wavelength of 550-700 nm. The indigo dyes in various concentrations produce a stable pH at an average pH 9, therefore it can make the colors not easily fade (strong staining). Based on infrared spectrophotometer measurement were obtained absorption spectrum at 3100-3500 cm^-1 as primary N-H and secondary amine, 1600 cm^-1 as aromatic C=C, 1000-1350 cm^-1 as aromatic C-N, 690-900 cm^-1 as aromatic C-H.

Al doped ZnO (AZO) nanoparticles have been successfully synthesized by the simple sol-gel method. The starting materials of Al doped ZnO were Zn(CH₃COO)₂2H₂O and Al(OH)(CH₃COO)₂. Preparation of AZO using polyethylene glycol as a surfactant. The solution of precursors was stirred at 60 °C for 2 hour in the conditions of Al contents are 0%, 2%, 3% and 4% (g/mL), respectivelly. In the last step reaction, gelation occurred from solution to sol gel. The sol gel then were dried at 60 °C following by annealing process for crystalization. By this simple sol gel method, the nanoparticles have been produced. The characterizations were conducted X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Fourrier Transform Infra-Red (FTIR) and X-Ray Fluorescence (XRF). XRD analysis reveals that all samples has crystallizes in polycrystalline nature and exhibit no other impurity phase. The variation of Al doped ZnO slighly affect the crystallinity and crystal size. Both crystallinity and crystal size decrease with increasing of Al content in AZO. Morphology of AZO shown the particle distribution more equitable with increased Al content. The synthesized AZO gaved shift peak absorption of asymetric and symetric vibrations of Zn-O-Zn around wavelengths of 680 cm^-1 and 1630 cm^-1 atributed of the uptake of the Al-O-Al bond instead Zn-O-Zn. XRF analysis shown that the increase ratio of Al entering into Zn influenced the Al dopant concentration.

Palm fresh fruit bunches (FFBs) are raw materials used in CPO mills and produced by palm oil plants. The nature and quality of these raw materials considerably affect the characteristics of the crude palm oil (CPO). The characteristic of crude palm oil (CPO) can be affected by freshness level, ripening of palm fruit bunches, growing sites, poor transportation and harvest and postharvest systems. Amongst the aforementioned factors, the major problems that occur frequently are the ripening level and processing delay of palm fresh fruit bunches (FFBs) and also brondolan (loose fruits from bunches). Harvested FFBs must be optimally ripened to achieve high oil content and must be immediately taken to the factory for processing. Accordingly, the present study aims to evaluate the characteristics of palm oil produced at different ripening levels and processing delay times of palm fruit bunches from oil palm plantations in Ungaran, Central Java, Indonesia. The objects of this research are ripening level (underripe, ripe, overripe and brondolan) and processing delay time (12, 36 and 60 h). Results show that the ripening level and length of processing delay of palm fruit bunches can affect the deterioration of bleachability index (DOBI) value, free fatty acid (FFA) content, oil content, peroxide value (α = 0.05) and profile of fatty acid composition. A long processing delay increases FFA content and peroxide value, but decreases DOBI value and oil content. From the observed parameters, the best results are found on ripe FFBs with a processing delay time of 12 h. The results are still good at 36 h but deteriorated after 60 h.