Key-Marker Volatile Compounds in Aromatic Rice (Oryza sativa) Grains: An HS-SPME Extraction Method Combined with GC×GC-TOFMS

Abstract

The aroma of rice essentially contributes to the quality of rice grains. For some varieties, their aroma properties really drive consumer preferences. In this paper, using a dynamic headspace solid-phase microextraction (HS-SPME) system coupled to a two-dimensional gas chromatography (GC×GC) using a time-of-flight mass spectrometric detector (TOFMS) and multivariate analysis, the volatile compounds of aromatic and non-aromatic rice grains were contrasted to define some chemical markers. Fifty-one volatile compounds were selected for principal component analysis resulting in eight key-marker volatile compounds (i.e., pentanal, hexanal, 2-pentyl-furan, 2,4-nonadienal, pyridine, 1-octen-3-ol and (E)-2-octenal) as responsible for the differences between aromatic and non-aromatic rice varieties. The factors that are most likely to affect the HS-SPME efficiency for the aforementioned key-marker compounds were evaluated using a 2III5−2 fractional factorial design in conjunction with multi-response optimisation. The method precision values, expressed as % of coefficient of variation (CV), were ranging from 1.91% to 26.90% for repeatability (n = 9) and 7.32% to 37.36% for intermediate precision (n = 3 × 3). Furthermore, the method was successfully applied to evaluate the volatile compounds of rice varieties from some Asian countries.

Volatile Organic Compound Based Markers for the Aroma Trait of Rice Grain

“…This could possibly be construed to imply that not all volatile biochemical markers are aroma active compounds. This would be in contrast to the study by Setyaningsih et al (2019) in which all the seven volatile biochemical markers were aroma active compounds. Hence, the present study deemed it necessary to further refine the list of possible volatile biochemical markers by subjecting the VOCs to correlation and regression analyses.…”

“…Further multivariate analyses revealed; toluene; 2,3-dioxabicyclo[2.2.1]heptane, 1-methyl-; hydroxylamine, O-decyl-; ethanol, 2-butoxy; undecane, 2,6-dimethyl; methyl acetoacetate; 1-hexanol, 2-ethyl; benzene, 1,2,3-trimethyl-; heptane, 2,2,4,6,6-pentamethyl-and benzene, 1,2,4,5-tetramethyl-as candidates for volatile biochemical markers of the rice aroma trait. With the exception of 2-ethyl hexanol, all identified volatile markers in the three studies were not similar (Griglione et al, 2015;Setyaningsih et al, 2019). Importantly, careful examination of all earlier reported volatile markers indicated that the compounds were aroma active.…”

“…With regards to identifying possible volatile biochemical markers for the aroma trait in rice, earlier studies have established the reliability of GC-MS techniques coupled with multivariate analyses. Setyaningsih et al (2019) reported that out of 51 volatile organic compounds subjected to principal component analysis, seven key-marker volatile compounds namely; pentanal, hexanal, 2-pentyl-furan, 2,4-nonadienal, pyridine, 1-octen-3-ol and (E)-2-octenal were able to differentiate between non-aromatic and aromatic rice. The authors postulated that these volatile compounds were key-markers for the rice aroma trait.…”

Identifikasi Komponen Volatile Kulit Ari Biji Kopi (Coffea robusta) Guna Optimalisasi Kebermanfaatan

“…Maka dari itu, penelitian ini bertujuan mencari senyawa marker (penanda) dari kulit ari biji kopi robusta (C. robusta) yang mampu menjadi standar kualitas senyawa yang dicari untuk bahan baku produk absorbent dengan metode GC-MS. Kedepannya, senyawa marker (penanda) akan mampu digunakan oleh berbagai produsen yang menggunakan kulit ari biji kopi robusta sebagai bahan baku produk absorbent sekaligus pengharum natural sebagai bentuk quality control produk yang dihasilkan [6]. Komponen volatile yang ditemukan melalui GC-MS tergolong sebagai prediksi komponen dan ke depannya akan dipelajari lebih lanjut.…”

Identification of Key Volatiles Differentiating Aromatic Rice Cultivars Using an Untargeted Metabolomics Approach

“…Furthermore, hexanal, octanal, nonanal, ( E )-2-octenal, decanal, 1-heptanol, and 1-octanol were identified as major aroma-active compounds in Jasmine rice [ 11 ]. Widiastuti et al [ 12 ] using a dynamic headspace solid-phase extraction system coupled to a two-dimensional gas chromatography (GC × GC) coupled with a time-of-flight mass spectrometric detector (TOFMS) to distinguish the aromatic from non-aromatic rice grains. Fifty one kinds of volatile compounds were detected by this methods, and eight key-marker volatile compounds (i.e., pentanal, hexanal, 2-pentylfuran, 2,4-nonadienal, pyridine, 1-octen-3-ol and ( E )-2-octenal) were selected for identifying the aromatic rice of Indonesia.…”