Optimization of Process Parameters of Parboiled Black Rice Using Response Surface Methodology

Reza Widyasaputra^1,2, Elvira Syamsir^1*, Slamet Budijanto¹

¹Department of Food Science and Technology, IPB University, Bogor, West Java, Indonesia
²Department of Agricultural Technology, Institute of Agricultural Stiper Yogyakarta, Sleman, Yogyakarta, Indonesia

Corresponding Author Email: elvira_tpg@yahoo.com

Black rice is well known as healthy food. Nowadays, some people try to change their diet with this rice. However, it still has a problem with long preparation time and hard texture. Parboiling is a hydrothermal process that changes rice starch from crystalline to amorphous. The parboiling process of rice consists of soaking in sodium citrate solution, high-pressure cooking, freezing-thawing and drying. The aim of this research was to find the optimum condition from three processing variables: concentration of sodium citrate (0, 2, 5 and 5%, w/v), cooking period in an autoclave (5, 10 and 15 min) and a number of freeze-thaw cycles (1, 2.5 and 4). The optimum condition was achieved with 3.8% sodium citrate concentration, 5 min cooking in an autoclave, and 3.8 freeze-thaw cycles. This optimum condition resulted in parboiled black rice with 25.84 min cooking time, 4.93 total colour difference 101.80 N hardness of cooked rice, 49.04 N chewiness of cooked rice, 5.32 kg rice grain hardness.

Black Rice; Cooking Time; Parboiled Rice; Process Optimization

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