An experimental study was performed to determine the drying characteristics of dried papaya using different drying methods. They were dried using several methods, such as sun drying, solar drying, oven drying, and microwave drying. The effects of different operating conditions on physical quality attributes were investigated. The papaya were cut into different thicknesses and cooked in sugar syrup with different sugar concentration for 24 hours. Three different temperature settings were used in oven and microwave drying. The drying curve and drying rate of each method, temperature, sample
thickness and sugar concentration were studied. The drying times were found as in 6-15 minutes, 5 to 11 h, 10 to 18 h, and 14 to 23 h for the microwave, oven, sun and solar drying, respectively. The drying time increased with the increase of sample thickness and sugar concentration, as well as with the decrease of the drying temperature. In this study, quality attributes like colours and textural property of dried papaya were explored. Among the various methods of the drying characteristics
of papaya halwa, oven drying was preferred with the optimum sample in 5 mm thickness and at the air temperature of 70ºC as it saved up to 40% of the drying time as compared to other methods, except microwave, and produced acceptable physical quality of product.
This study was conducted to determine the influence of raw material variation, equipment
process variables and device stability on the drying process of rambutan seed using oven and
microwave drying equipments. The raw material variations studied were skin colour (yellow
and fully red), storage period (fresh and stored) and seed mass (5 and 10 g). The important
equipment process variables studied were oven temperature (40 and 60°C) and microwave
power (250 and 1000 W).The output power and drying distribution in the drying chamber were
studied to examine the device stability. Results indicated that the seed mass, oven temperature
and microwave power influenced the drying time. The skin colour and storage period were
negatively correlated with drying time due to drying time speculate to relay on time required for
moisture removal that associated to initial moisture content and seed mass. It is also observed
that the drying time will be shorten if the sample was located at the central of the microwave
drying chamber. In contrast, the oven exhibited higher stability compared to microwave due
to its ability to provide similar level of heating at each location in the drying chamber. This
information will aid researchers and industrial operators to design an effective drying process
using microwave and oven thus reducing cost and time.
A study has been conducted on pink guava juice (PGJ) fouling deposit. Several ex-situ experimental rigs were set-up to obtain PGJ fouling deposit, while the best ex-situ experimental rig was also selected. PGJ was heated at 93°C and its fouling deposit was obtained after 1 hour of heating. Then, it was used for the ex-situ cleaning study at 1 litre min-1, at several temperatures (70, 80 and 90°C), and in some chemical concentrations (1.6 v/v% of Maxiclean CP6 or 0.325 % OH-; 1.8 v/v% of Maxiclean CP6 or 0.369 % OH-; 2.0 v/v% of Maxiclean CP6 or 0.44 % OH-). The best cleaning combinations were investigated. Carbohydrate is the main content in the fouling deposit. The morphology of the deposit was studied using SEM and it showed an aggregated structure. The cleaning process improved as the temperature increased with the increasing of the chemical solution concentration. The shortest cleaning time was 40 minutes, for cleaning using 2.0 v/v % of Maxiclean CP6 (0.44 % OH-) at 90°C.
Implication of drying techniques in preservation of fruit juice has huge advantage in quality control and packaging sector. The objective of this research was to investigate the effect of drying techniques and maltodextrin concentrations on physicochemical attributes of pink guava powder. Pink guava puree was dried at -110ºC and 0.001 mbar by freeze drying and at 170ºCinlet air temperature and 350 ml/hr feed flow rate by spray drying with 10-20% maltodextrin concentration (MDC). The drying methods (DM) and MDC had significant effect on powder properties. Spray drying was more effective reducing the moisture content and water activity to 2.86% and 0.377, respectively, whereas, freeze drying was more suitablein the retention of color, lycopene and vitamin C. Spray drying was more economic method compared to freeze drying. Overall, spray-dried pink guava powder produced with 20% MDC had better quality than that of freeze-dried powder in terms of lowest moisture content (2.17%), lowest water activity (0.33), highest glass transition temperature (215ºC), less electricity and time consumption, anda moderate retention of lycopene and vitamin C.
Aquaculture is a growing industry with a great potential towards the contribution of the country’s total
fish requirement. Serious efforts have been done to develop and improve the production of fish by rearing high value fish in tanks or ponds. Under the Third National Agricultural Policy (1998-2010), the target is to annually produce 1.93 million tonnes of fish worth approximately RM8.3 billion by the year 2010. Consequently, the development of an automatic fish feeding machine can be very beneficial to the growth of the aquaculture industry. This device was developed to overcome labour problems in the industry and introduce a semi-automatic process in the aquaculture industry. It has the ability to dispense dried fish food in various forms such as pellets, sticks, tablets or granules into fish tanks or ponds in a controlled manner for a stipulated time. The automatic fish feeder is controlled by a digital timer and it is capable of feeding the fish in accordance with a pre-determined time schedule without the presence of an operator, and at a feeding rate of 250g/min. The feeder can be adjusted to the desired height and conveniently moved around to be positioned adjacent to the pond or tank. Meanwhile, its hopper can be covered and easily dissembled to change the size of the hopper to accommodate different capacities of feed. This automatic fish feeder can be implemented in aquaculture system to convenience to fish culturists.
Dadih is a favourable dessert in South East Asia due to its appealing sweet taste and jellies
appearance. The sweet taste is from sugar (sucrose) content, and in order to reduce the sucrose,
it was substituted with xylitol. Xylitol can provides intense sweetness with less calories and
lower water activity, which potentially contribute to higher microbial stability thus giving
longer shelf life. The objective of this study was to evaluate the effect of xylitol substituted
on dadih safety and sensory qualities. Dadih was prepared by replacing sucrose with xylitol
composition in the range of 0 – 100% and at two levels of cooking times (15 and 20 minutes).
Safety analysis were performed using total plate count (TPC) and water activity (aw) analysis.
For sensory analysis, seven attributes were evaluated (appearance, colour, hardness, elasticity,
taste, sweetness, and overall acceptability) based on the 9-hedonic scale. From the findings,
dadih samples with total sucrose (0%) were observed to be contaminated faster compared to
total xylitol (100%). Dadih with xylitol is more stable with prolonged shelf life. From sensory
analysis, dadih sample prepared with shorter cooking time (15 minutes) was selected as more
favourable with overall acceptability score between 72 - 85%. More than 70% of the score for
dadih with xylitol substitute was above ‘slightly like’, which indicates a promising future to
produce xylitol substitute dadih. The outcome of this study has shown that xylitol is potentially
to be utilize as sugar substitute for dadih production.