ISSN 2630-0583 (Print)

ISSN 2630-0656 (Online)

JCST

Journal of Current Science and Technology

http://jcst.rsu.ac.th

Rangsit Journal of Arts and Sciences. Vol.4 No.2 , July - December 2014.

A method for reducing rancidity in germinated brown rice flour

Narumon Loikaeo, Benjarak Vayupharp, and Varaporn Laksanalamai

Abstract

           Germinated parboiled brown rice (GPBR) is the rice that has been soaked, germinated, and steamed in the husk before drying and then dehusked.  The objective of this research was to study the effect of slightly acidic soaking water (pH 5.6) on the inactivation of lipase activity, hence, retarding the rancidity in GPBR.  The shelf life of germinated brown rice flour (GBF) was also determined.  Results were compared with GPBR produced by the process of the local community (soaking in tap water, pH 7.0).  We suggested soaking rough rice in slightly acidic water for 36 h followed by germinating, and steaming to 16 h, and 15 min, respectively.  This has been shown to decrease the lipase activity and retard the development of PV and TBA value as compared to the process of the local community.  Moreover, the process of soaking in the slightly acidic water for 36 hours promoted GABA content in GPBR to the highest value of 25.70 mg/100 g dry matter.  Shelf life of GBF produced from both processes was slightly different, varying between 64-67 days at 30°C.  When storage temperature increased, different shelf lives of GBF produced from such processes were documented.  Soaking rough rice in the slightly acidic water is therefore one method to prevent lipase activity.  Other strategies to improve GBF storage stability should focus on methods to inactivate lipoxygenase and lipase activity, thus halting or slowing the early stages of lipid degradation and retard rancidity.

Keywords: rancidity, germinated parboiled brown rice, shelf life

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