Comparative Profiling of Volatile Compounds in Popular South Indian Traditional and Modern Rice Varieties by Gas Chromatography-Mass Spectrometry Analysis

Kaliyaperumal Ashokkumar; Mahalingam Govindaraj; Sampathrajan Vellaikumar; V G Shobhana; Adhimoolam Karthikeyan; Manoharan Akilan; Jeyaraman Sathishkumar

doi:10.3389/fnut.2020.599119

Comparative Profiling of Volatile Compounds in Popular South Indian Traditional and Modern Rice Varieties by Gas Chromatography-Mass Spectrometry Analysis

Front Nutr. 2020 Dec 9:7:599119. doi: 10.3389/fnut.2020.599119. eCollection 2020.

Authors

Kaliyaperumal Ashokkumar^{1

2}, Mahalingam Govindaraj³, Sampathrajan Vellaikumar⁴, V G Shobhana³, Adhimoolam Karthikeyan⁵, Manoharan Akilan⁶, Jeyaraman Sathishkumar²

Affiliations

¹ Crop Improvement, Cardamom Research Station, Kerala Agricultural University, Pampadumpara, India.
² School of Agriculture, PRIST Deemed University, Thanjavur, India.
³ Crop Improvement Program, International Crops Research Institute for the Semi-Arid Tropics, Hyderabad, India.
⁴ Agricultural College and Research Institute, Tamil Nadu Agricultural University, Madurai, India.
⁵ Subtropical Horticulture Research Institute, Jeju National University, Jeju, South Korea.
⁶ Department of Plant Breeding and Genetics, Agricultural College and Research Institute, Tamil Nadu Agricultural University, Madurai, India.

Abstract

Rice (Oryza sativa L.) is one of the major cereal crops cultivated across the world, particularly in Southeast Asia with 95% of global production. The present study was aimed to evaluate the total phenolic content (TPC) and to profile all the volatile organic compounds (VOCs) of eight popular traditional and two modern rice varieties cultivated in South India. Thirty-one VOCs were estimated by gas chromatography-mass spectrometry (GC-MS). The identified volatile compounds in the 10 rice varieties belong to the chemical classes of fatty acids, terpenes, alkanes, alkenes, alcohols, phenols, esters, amides, and others. Interestingly, most of the identified predominant components were not identical, which indicate the latent variation among the rice varieties. Significant variations exist for fatty acids (46.9-76.2%), total terpenes (12.6-30.7%), total phenols (0.9-10.0%), total aliphatic alcohols (0.8-5.9%), total alkanes (0.5-5.1%), and total alkenes (1.0-4.9%) among the rice varieties. Of all the fatty acid compounds, palmitic acid, elaidic acid, linoleic acid, and oleic acid predominantly varied in the range of 11.1-33.7, 6.1-31.1, 6.0-28.0, and 0.7-15.1%, respectively. The modern varieties recorded the highest palmitic acid contents (28.7-33.7%) than the traditional varieties (11.1-20.6%). However, all the traditional varieties had higher linoleic acid (10.0-28.0%) than the modern varieties (6.0-8.5%). Traditional varieties had key phenolic compounds, stearic acid, butyric acid, and glycidyl oleate, which are absent in the modern varieties. The traditional varieties Seeraga samba and Kichilli samba had the highest azulene and oleic acid, respectively. All these indicate the higher variability for nutrients and aroma in traditional varieties. These varieties can be used as potential parents to improve the largely cultivated high-yielding varieties for the evolving nutritional market. The hierarchical cluster analysis showed three different clusters implying the distinctness of the traditional and modern varieties. This study provided a comprehensive volatile profile of traditional and modern rice as a staple food for energy as well as for aroma with nutrition.

Keywords: GC-MS analysis; Oryza sativa L.; total phenol; traditional aromatic rice; volatile organic compounds.