Rheological and textural characteristic of restructured fruit puree

Sago starch is a cheap form of starch which is isolated from sago palm (Metroxylon spp.) and is available in abundance in South East Asian countries. Given its low cost, Sago starch has great potential to be used as a substitute for other forms of starch. The objectives of this work were to study the effects of paste concentration on the rheological behaviour of sago starch paste, their texture properties and their freeze thaw stability compared to other types of starch. The rheological properties of sago starch were investigated at different paste concentrations (3-8 wt %). The textural properties of the samples were investigated by examining the gel strength of the samples. The percent syneresis of sago starch was also studied to examine the freeze-thaw stability of the material. The freeze thaw stability of sago starch with the addition of certain biopolymers were also characterized

Rheological Behaviour Of Coconut Milk: Effects Of Concentration And Temperature

The rheological behaviour of coconut milk was studied using a Haake rotational viscometer having a concentric cylinder geometry sensing system. The rheological model of coconut milk, incorporating the effects of concentration and temperature was developed. Experiments were conducted at 4 levels of temperatures in the range of 5°C to 65°C and 6 levels of concentrations ranging from 10 % to 50 % total solid (TS) . The hysteresis effect was examined by varying the shear rate in an ascending order from IS-I to 1000 S-1 followed by a descending order (1000 s-1 to Is- 1 ) . The coconut milk, within the ranges of concentration and temperature studied, exhibited different rheological behaviours. Two rheological models, namely the Newtonian and Power Law model were applied to fit the experimental data. The coconut milk with concentrations of lower than 2 5% TS exhibits Newtonian behaviour. For TS of between 2 5% to 50 %, coconut milk behaves more like a Power L aw fluid. Coconut milk that exhibits Newtonian behaviour was of low concentration while coconut milk that follows the Power Law model was of high concentration. The apparent viscosity for low concentration coconut milk showed an exponential type dependence on the concentration while the effect of temperature on the apparent viscosity obeyed the Arrhenius type relations hip. The high concentration coconut milk was of a s hear thinning fluid with a flow behaviour index , n = 0.567. The flow behaviour index was not significantly affected by the concentration and the temperature in the study. The effect of temperature on the consistency coefficient in Power Law model obeyed the Arrhenius type equation. The effect of concentration on the consistency coefficient obeyed an exponential type equation. The general mathematical models were developed to represent the combined effects of concentration and temperature for low concentration as well as for high concentration coconut milk . Each model developed showed accurate prediction of shear rate. The magnitude of the activation energy, Ea for low concentration coconut milk was 3 720.03 cal/mol which was lower than that of high concentration coconut milk (4236.63 cal/mol). An F-tes t was carried out on the magnitude of s hear s tress for ascending and descending order s hear rates for high concentration coconut milk irrespective of concentration, temperature and shear s tress . The test showed that there was no significant difference in the magnitude of shear stress . This indicates that there is no significant effect of time on the rheological behaviour of coconut milk

Chemical composition changes of two water apple (Syzygium samaragense)

Changes in physical properties (weight, size, colour and weight loss) and chemical properties (proximate analysis, TSS, pH, freezing point, total acidity and sugar content) of two water apple (Syzgium samaragense) cultivars, Semarang Rose and Kristal Taiwan were evaluated during ripening at 10°C and 50% RH. The results showed that the Kristal Taiwan cultivar was larger in size and weight but smaller in length compared to Semarang Rose. The Semarang Rose cultivar was sweeter than Kristal Taiwan. In this study, data obtained suggests that the water apple fruit can be stored at cold storage until 19 days

Physico-chemical compositions of the red seedless watermelons (Citrullus Lanatus)

Changes of physico-chemical properties such as size, weight, moisture content, total soluble solid (TSS), colour, pH, total acidity and sugar content of red seedless watermelon during storage at room temperature (± 28°C; 70-80% RH) were investigated. The average weight, diameter and length of red seedless watermelon were 5.94 kg, 22.0 cm and 21.8 cm respectively. The length to diameter ratio was 1.02. The statistical analysis indicated that total soluble solids of fruit decreased significantly (p<0.01), but no significant changes were found in pH and total acidity during ripening. Weight loss, moisture content and freezing point was found to be increased significantly (p<0.01) during ripening. Colour L* was found no significant changes but colour a* and b* increased significantly (p<0.1) throughout the ripening process. For sugar analysis, significant changes (p<0.1) in fructose and glucose were obtained, but no significant changes were observed in sucrose content during storage time. From the observation, the optimum eating quality of watermelon stored in room temperature (± 28°C; 70-80% RH) was within one week after harvest, although they can be stored up to 2 weeks. The data obtained is vital in order to apply in different field, purpose and application

Chemical compositions of the jackfruit juice (Artocarpus) cultivar J33 during storage

Chemical properties such as pH, total acidity, Total Soluble Solid (TSS) and sugar content changes during ripening of jackfruit cultivar J33 were evaluated at ambient temperature (±27°C; 70-80% RH). There are significant changes pH, total soluble solids, total acidity and sugar content at different ripening days. In this study, data obtained suggests that the ripening process of jackfruit cultivar J33 was at its optimum at day 9 after harvest at ambient temperature. The results will help to make the best use of jackfruit for different purposes and applications

Preliminary work on coconut milk fouling deposits study

The characterizations of coconut milk fouling deposits formed during pasteurization process at temperature from 70 to 80ºC were investigated. Both in-situ (using lab-scale plate heat exchanger) and ex-situ methods (using shakable water bath) were applied in preparing the fouling sample and for cleaning study. A few microanalyses such as proximate analysis, texture analysis and microstructure analysis were carried out to examine the characteristics of the coconut milk fouling deposits. Selection of raw material and determination of the optimal process parameters for pasteurization process were done to obtain a typical pasteurization condition as applied in the coconut milk product industry in Malaysia. The changes of the overall heat transfer coefficient (U) during the process were studied. The removal/cleaning of coconut milk fouling deposit was also studied at 80°C, 2 LPM and with 2 %V/V hydroxide of alkaline solution (optimal condition obtained from ex-situ method). The results indicate that fouling period was occurred during coconut milk pasteurization and it caused a resistance to heat transfer. Coconut milk fouling deposit which contains of high fat content (29.25%) can be removed by applying single stage clean-in-place (CIP) method with alkaline solution. The factors causing fouling were studied

Carbon dioxide adsorption on activated carbon hydrothermally treated and impregnated with metal oxides

Activated carbon (AC) has been used widely as an agent for carbon dioxide (CO2) adsorption due to its environmentally friendly nature, low cost, high porous structure, high surface area and good mechanical properties. Modifications have been made to AC in order to enhance its adsorptive properties. In this study, the performance of activated carbon modified by hydrothermal treatment and impregnation techniques was compared using metal oxides. The prepared samples were characterized by different techniques using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The adsorption of CO2 was investigated using a CO2 adsorption unit, whereby 20% of CO2 gas was passed through the samples until a breakthrough point was achieved. During the adsorption study, it was found that AC that had been hydrothermally treated with cerium oxide (CeO2) had the highest adsorption capacity of 0.856 mmol/g with a breakthrough time of 19.33 min