OPTIMISATION OF GERMINATION TEMPERATURE AND TIME TO IMPROVE γ-AMINOBUTYRIC ACID, POLYPHENOLS AND ANTIOXIDANT ACTIVITY IN BROWN RICE 1 Escuela Superior Politecnica del Litoral (ESPOL), Guayaquil, Ecuador 2 Institute of Food Science Technology and Nutrition (ICTAN-CSIC), Madrid, Spain 3 Institute of Food Science Research (CIAL-CSIC/UAM), Madrid, Spain Rice (Oryza sativa L.) is a staple food for over half of the world's population. From a nutritional point of view, brown rice is preferred since contains higher dietary fiber, B-vitamins and minerals than white rice as well as healthy phytochemicals such as γ- oryzanol, γ-aminobutyric acid (GABA) and polyphenols 1. Germination is an effective and cheap process that improves not only the nutritional quality of cereals but also GABA, polyphenols and antioxidant activity are accumulated in sprouts 2. During germination, the synthesis and accumulation of phytochemicals are highly affected by operating parameters such as time and temperature. This research was aimed to maximise antioxidant activity (ORAC), total phenolic compounds (TPC) and GABA optimizing temperature and time during the germination of two varieties of brown rice using the response surface methodology (RSM). INTRODUCTION OBJECTIVE MATERIAL AND METHODS Long-grain brown rice varieties 15 and 17 were provided by the National Institute of Agricultural Research from Ecuador -INIAP-. GABA content was determined by HPLC and confirmed by HPLC-MS 3. Total phenolic compound content (TPC) was determined by the Folin-Ciocalteau 4. Antioxidant capacity was evaluated by the oxygen radical absorbance capacity method (ORAC) 5. Response surface methodology (RSM) was constructed using Statgraphic 5.0 program for Windows. RESULTS Patricio Cáceres-Costales 1, Cristina Martínez-Villaluenga 2, Lourdes Amigo 3, Juana Frias 2 Variety 17 RSM diagrams for GABA (mg/ 100g dm), antioxidant activity (ORAC, µmol Trolox Equiv/g dm) and total phenolic compounds (TPC, mg GAE/g dm) of brown rice varieties germinated at different conditions. CONCLUSIONS Variety 15 ORAC TPC GABA  RSM plots showed that germination time and temperature influenced GABA, TPC and ORAC (P<0.05).  Higher germination time conducted to larger GABA content and slight differences between varieties were found (Figure 1).  Lower temperature and longer germination time brought about the highest TPC; and significant differences between varieties were found. (Figure 2).  Higher temperature throughout germination time let to larger antioxidant activity and sharp differences between varieties were found (Figure 3).  Germination of variety 15 led to larger bioactive compound retention than variety 17.  Germination of brown rice variety 15 should be selected for germination at 28 ºC for 96 h to achieve the optimum GABA, TPC and antioxidant activity.  The RSM proved to be useful for optimization of germination process. REFERENCES 1 Min B, Gu L, McClung AM, Berman CJ, Chen ML (2012) Food Chem 133, Kim H-Y, Hwang IG, Kim TM, Woo KS, et al. (2012) Food Chem 134, Torino MI, limon, RI, Martinez-Villaluenga, C., Mäkinen et al. (2013). Food Chem 136: Singleton VL, Orthofer R, Lamuela-Raventos RM. (1999). Methods of Enzymology, 299, 152– Martinez-Villaluenga C, Peñas E, Sidro B, Frias J, Vidal-Valverde C. (2012) LWT - Food Sci. Technol. 2012, 46: