Setia Budi Sasongko

Carrageenan drying with dehumidified air: drying characteristics and product quality

Abstract Applying dehumidified air is considered as an option to retain quality in carrageenan drying. This work concerns the effects of operational temperature, air velocity, and carrageenan thickness on the progress of drying and product quality when using dehumidified air. Final product quality and progress of drying were measured by experiments, and a two dimensional model was developed to analyze progress of drying for the different operational conditions. The experimental and modeling results showed that air dehumidification with zeolite reduces the drying time the most at low temperatures. Under these conditions the carrageenan qualities whiteness and gel strength are the least affected by the exposure to the drying temperature. The drying time is the shortest at 120°C, but at this temperature the carrageenan quality degrades the most and is not be improved by air dehumidification. Moreover, the quality is improved by increasing the air velocity and by drying thin carrageenan sheets.

Synthesis of Ca/MgO catalyst using sol gel method for monoglycerides production

This paper discusses Ca-doped MgO catalysts using Sol-Gel method. The doping of Ca is expected to increase the basicity of the catalyst. The basicity of catalyst has effect on the monoglycerides production by glycerolysis reaction. The Ca/MgO catalyst was prepared by sol gel method by using solution as a precursor. This method was expected to produce a more homogeneous mixture of Mg and Ca. The catalyst was characterized using X-Ray Diffraction (XRD) and the basicity was analyzed using Hammett titration method. The monoglycerides yield was analyzed using Gas Chromatography Mass Spectrometry (GC/MS). Based on Hammett’s titration method, the basicity value was calculated in which the largest value was obtained by the dopant concentration of 2% Ca and calcination temperature of 800°C. The 2% Ca/MgO catalyst that has the highest basicity value was tested for the production of monoglycerides through glycerolysis reaction. This reaction carried on the conditions of 200°C, the catalyst amount of 0.1% weight of oil, the ratio of glycerol : oil = 3 : 1, reaction time of 3 hours, and stirring speed of 700 rpm. The composition of monoglyceride on oil phase product was 100%, while without catalysts composition was 7.43%.This paper discusses Ca-doped MgO catalysts using Sol-Gel method. The doping of Ca is expected to increase the basicity of the catalyst. The basicity of catalyst has effect on the monoglycerides production by glycerolysis reaction. The Ca/MgO catalyst was prepared by sol gel method by using solution as a precursor. This method was expected to produce a more homogeneous mixture of Mg and Ca. The catalyst was characterized using X-Ray Diffraction (XRD) and the basicity was analyzed using Hammett titration method. The monoglycerides yield was analyzed using Gas Chromatography Mass Spectrometry (GC/MS). Based on Hammett’s titration method, the basicity value was calculated in which the largest value was obtained by the dopant concentration of 2% Ca and calcination temperature of 800°C. The 2% Ca/MgO catalyst that has the highest basicity value was tested for the production of monoglycerides through glycerolysis reaction. This reaction carried on the conditions of 200°C, the catalyst amount of 0.1% weight of o...

Drying Rate and Product Quality Evaluation of Roselle (Hibiscus sabdariffa L.) Calyces Extract Dried with Foaming Agent under Different Temperatures

The utilisation of roselle (Hibiscus sabdariffa L.) calyx as a source of anthocyanins has been explored through intensive investigations. Due to its perishable property, the transformation of roselle calyces into dried extract without reducing their quality is highly challenging. The aim of this work was to study the effect of air temperatures and relative humidity on the kinetics and product quality during drying of roselle extract foamed with ovalbumin and glycerol monostearate (GMS). The results showed that foam mat drying increased the drying rate significantly and retained the antioxidant activity and colour of roselle calyces extract. Shorter drying time was achieved when higher air temperature and/or lower relative humidity was used. Foam mat drying produced dried brilliant red roselle calyces extract with better antioxidant activity and colour qualities when compared with nonfoam mat drying. The results showed the potential for retaining the roselle calyces extract quality under suggested drying conditions.