This work describes the effects of different cooking temperatures in repetitive cooking-chilling (RCC) process on resistant starch (RS) content in fish crackers prepared in a ratio of 1:1 fish to sago starch formulation. In this work, three sets of four RCC cycles were performed on fish crackers, in which each set was cooked at fixed temperatures of 100, 115 and 121°C, respectively. The chilling temperature was fixed at 4°C in all cases. Subjecting the fish crackers to a higher cooking temperature for up to 4 cycles of RCC can increase the RS content. However, quality degradation was observed in the characteristics of the fish crackers. During the first RCC cycle, cooking at a higher temperature had caused the crackers to crack and burst. Besides, defragmentation to the shape of the fish cracker gels was also observed during the first RCC cycle, coupled with softer texture and high moisture content. When the products were subjected to frying, their linear expansion decreased, the texture became harder and the colour turned darker. This work demonstrated that the application of higher cooking temperature up to 4 RCC cycles was able to enhance the RS content in the fish crackers, but it was less able to attain the product's perfect shape. On the contrary, fish crackers that were exposed to lower cooking temperatures contained lower RS but with less shape damage.
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.