Assessment of Flavor Volatiles of Iranian Rice Cultivars during Gelatinization Process

A combined gas chromatography-mass spectrometry (GC-MS) with headspace solid-phase micro extraction (SPME) method has been employed for the analysis of the flavor volatiles of three different rice cultivar, including two modified Iranian rice cultivars and Hashemi rice cultivar during gelatinization. The proposed combination provided a powerful system for easy and rapid screening of a wide range of flavors in fragrant rice samples. In order to optimize the different experimental parameters, the effect of fiber composition, water content of rice samples and equilibrium time were investigated. As a result, while the gelatinization was in progress, the amount of the volatile compounds was increased as well. All of the free flavor volatiles, the bound flavor components and the compounds formed by the thermal decomposition of the non-volatile constituents existing in rice could be liberated during the gelatinization process. Therefore, a broad range of the flavor volatiles of rice could be extracted, concentrated and identified. Altogether, 75, 55 and 66 components were identified for Hashemi, HD5 and HD6 rice samples, respectively, which 58 unique compounds were not detected previously. The identified volatile components in the three Iranian rice cultivars belong to the chemical classes of aldehydes, ketones, alcohols and heterocyclic compounds, as well as fatty acids and esters, phenolic compounds and hydrocarbons.