Development of Low Calorie, Unpolished Rice Snacks using Laboratory Twin Screw Extruder

Abstract

High fiber, low calorie snack products from unpolished rice, processed by Hermann Berstorff Laboratory Co-rotating Twin Screw Extruder ZE 25x33D was studied. Puffed unpolished rice was mixed with roasted peanut, sesame seed or sunflower seed, or pumpkin, corn or mungbean flake, and shaped using gel binder. The result of 9-hedonic evaluation showed that puffed unpolished rice mixed with corn flake, had higher scores of appearance, odor, taste and acceptability than other formulas. However, scores of all formulas were rather low according to hard crispy texture of 100% unpolished rice. To obtain better characteristics, 25% polished rice was added to unpolished rice and the texture became soft crispyness with acceptability more than other proportions. Chemical analysis showed that puffed rice mixed with mungbean flake contained the lowest calorie contents of 56.9 kcal/ 15 gram serving size and fiber content at 6 percent while sesame seed mixed with unpolished rice had the highest fiber content of 8.5 percent. For shelf life study, it was indicated that during 4 to 6 months storage at 26-27°C, 65%RH, peroxide value (PV) of hulled rice mixed with peanut or corn flake, packed in four layers laminating bags were not changed. But PV of sample with peanut packed in two plastic bags (polypropylene, PP) for 4 months was increased from 2.38 to 13.7 meq/kg, when kept until 6 months it was increased to 19.07 meq/kg. At the period of 6 months, corn flake mixed with unpolished rice showed lower changes of PV than peanut formula in either type of packagings. Moreover those formulas packed in laminated bags had PV and moisture contents lower than packed in PP bags.