Process and Machine for Production of Rice Analog from Broken Rice

Abstract

Depending upon the pre- and post-harvest operating conditions, cultivar of rice and the type of milling machinery used, the quantum of broken grains in the milled rice varies between 5 and 50 % in India. The broken rice is sold at a very low price. Considering the potential for value addition to this relatively cheaper byproduct of rice milling industry, the research work was undertaken to develop a process technology and machine for production of rice analog (whole rice grain shaped pasta product - artificial rice). Rice Analog was prepared from broken rice in conjunction with other protein materials (wheat gluten, blackgram flour, gelatin) as functional supplements. The optimum level of protein fortification was determined in relation to the cooking stability of the product. Based upon experimental data, a small capacity cold forming extruder type machine was designed and developed. The effects of different variables like extrusion speed, particle size of rice flour and type of feed ingredient on different machine parameters were studied and optimized in relation to the minimum leaching loss of the product found during cooking studies. Rice analog obtained at 60 rpm screw speed using rice flour particle size below 50 mesh (average particle size 133 µm), designated as composite flour, gave minimum leaching loss irrespective of the type of feed ingredients. Also, the drying characteristics of the rice analog were studied to decide the optimum drying parameters. The drying air temperature of 313 K at 0.5 m/s was found to be optimum to give desired quality parameters of the rice analogs containing either 12% gluten or 25% blackgram flour when they were compared with other control samples like raw rice and commercial wheat pasta in their cooking behaviour. Organoleptic evaluation of the cooked rice analog was carried out and compared with the cooked raw rice. The cooked product (rice analog) was found acceptable to the test panel. A process technology for the production of rice analog from broken rice was suggested along with the appropriate machine.