Abstract:
The objective of this research was to develop the carrot added rice cracker for baking with microwave. The first part was a consumer study for testing the product concept. From 100 respondents, 71 percent accepted the product concept and were interested in purchasing. The second part was to study the effects of amylose content in the formulas and the moisture content in pellets on the physical properties. Four formulas with different levels of amylose contents were prepared by varying ratio of glutinous rice flour to rice flour (40:0, 35:5, 30:10, and 25:15). The pellets were dried at 55 °C for 10, 12 or 14 hours.The results showed interactions between the 2 factors on moisture content, aw and physical properties of products. Products with higher amylose content and dried at longer time had lower puffing ratios, but had higher hardness and fracturability. Therefore, 2 formulas with glutinous rice flour: rice flour of 40:0 and 35:5 dried for 12 hr. were selected for the study on reduction of moisture content and aw of pellets, maltodextrin or guar gum were added at 0%, 0.1% or 0.2%. The results showed that adding maltodextrin or guar gum at higher percentage resulted in lower moisture content, aw and the puffing ratio, higher hardness and fracturability of the products. Products adding maltodextrin were harder and higher in fracturability when compare to the products adding guar gum at the same level. The products from the formulas with rice flour (35:5) were significantly harder and had less puffing ratio than the products from formulas without rice flour added (40:0) (p ≤ 0.05). Therefore, 2 formulas without rice flour (40:0) adding 0.1% maltodextrin or guar gum were selected. The third part was to study the puffing conditions by baking in microwave oven at 800, 900 and 1100 watt for 30, 35 and 40 sec. The results showed that electric power of the microwave oven did not significantly affect physical properties of the products. However, the product baked for longer time had lower moisture content and aw, but had higher puffing ratio. The selected formula was the one without rice flour (40:0) adding 0.1% guar gum, dried at 55 °C for 12 hr. Giving the pellet with low aw (0.689). It could be baked in microwave oven at 800- 1100 watt for 35± 5 sec. The 100 grams of the product contained 9.53 grams fat, 10.57 grams fiber and provided 375.37 calories, Fat content was under the industrial standard of cereal snack (TIS 1534-2541) and was similar to that of the commercial product. However the developed product had higher dietary fiber. From the Home Use Test, 94.3% of the respondents accepted the product . Shelf life study showed that the pellets could be kepted in metallized aluminum pouches and stored at room temperature for at least 3 month.