Thirty-three years of 2-acetyl-1-pyrroline, a principal basmati aroma compound in scented rice (Oryza sativaL.): a status review

Abstract

Rice is the staple food of around 3 billion people, most of them in Asia which accounts for 90% of global rice consumption. Aromatic rices have been preferred over non-aromatic rice for hundreds of years. They have a premium value in national as well as international market owing to their unique aroma and quality. Many researchers were involved in identifying the compound responsible for the pleasant aroma in aromatic rice in the 20th century. However, due to its unstable nature, 2-acetyl-1-pyrroline (2AP) was discovered very late, in 1982. Buttery and co-workers found 2AP to be the principal compound imparting the pleasant aroma to basmati and other scented rice varieties. Since then, 2AP has been identified in all fragrant rice (Oryza sativa L.) varieties and a wide range of plants, animals, fungi, bacteria and various food products. The present article reviews in detail biochemical and genetic aspects of 2AP in living systems. The site of synthesis, site of storage and stability in plant systems in vivo is of interest. This compound requires more research on stability to facilitate use as a food additive. © 2016 Society of Chemical Industry.

The Correlation between 2-Acetyl-1-pyrroline Content, Biological Compounds and Molecular Characterization to the Aroma Intensities of Thai Local Rice

“…The proline content ranged from 1.52 0.09 to 4.64 0.34 μg/g. Proline is the precursor for the 2AP synthesis pathway 4,10,18 .…”

“…An 8-base pair bp deletion has been reported in exon 7 of badh2 gene, which encodes the inactive betaine aldehyde dehydrogenase enzyme and is only found in fragrant rice 10,12 . Based molecule in the 2AP synthesis biochemical pathway 4,10,18 . Previous reports suggest that the level of 2AP is related to the level of proline.…”

Comparison of grain yield and 2-acetyl-1-pyrroline (2AP) content in leaves and grain of two Thai fragrant rice cultivars cultivated at greenhouse and open-air conditions

“…The aroma quality of fragrant rice is related to the content of an impact aroma compound, 2-acetyle-1-pyrroline, 2AP (Buttery et al, 1983;Widjaja et al, 1996;Maraval et al, 2008). This compound was firstly identified as a product of Maillard degradation in cooked rice and was found later in many processed and cooked foods (Wakte K et al, 2017). In contrast, our research group believes that 2AP is a naturally occurring compound and it is present in uncooked Jasmine rice (Mahatheeranont et al, 2001), soybeans (Juwattanasomran et al, 2011), sorghum (Yundaeng et al, 2013), coconuts (Saensuk et al, 2016) and winter melon (Ruangnam et al, 2017).…”

Quantitation of 2‐acetyl‐1‐pyrroline in aseptic‐packaged cooked fragrant rice by HS‐SPME/GC‐MS

“…Wide variation in the 2AP content of FR has been reported as a function of cooking status, variety, rice cultivation practices, environmental factors during cultivation, and postharvest processing (Itani, Tamaki, Hayata, Fushimi, & Hashizume, ; Mahmud, Oh, Kim, Cho, & Lee, ; Routray & Rayaguru, ; Wakte et al., ; Yoshihashi, Huong, Surojanametakul, Tungtrakul, & Varanyanond, ). Analysis protocols can also be a source of variations in 2AP content.…”

“…Interest in FR is increasing rapidly in Korea, with new varieties being optimized for the Korean climate and consumer palate. The flavor profiles of FR are produced by over 300 volatile compounds, among which 2-acetyl-1-pyrroline (2AP) is considered to be the most important in determining overall aroma (Buttery, Ling, Juliano, & Turnbaugh, 1983;Wakte et al, 2017;Wei, Handoko, Pather, Methven, & Elmore, 2017). Due to its importance, intensive research has been conducted on 2AP over the last 30 years since its identification in rice.…”