Reviews in Analytical Chemistry 2021; 40: 272–292 Review Article Vinita Ramtekey*, Susmita Cherukuri, Kaushalkumar Gunvantray Modha, Ashutosh Kumar*, Udaya Bhaskar Kethineni, Govind Pal, Arvind Nath Singh, and Sanjay Kumar Extraction, characterization, quantification, and application of volatile aromatic compounds from Asian rice cultivars https://doi.org/10.1515/revac-2021-0137 crop and deposits during seed maturation. So far, litera- received December 31, 2020; accepted May 30, 2021 ture has been focused on reporting about aromatic com- Abstract: Rice is the main staple food after wheat for pounds in rice but its extraction, characterization, and fi more than half of the world’s population in Asia. Apart quanti cation using analytical techniques are limited. from carbohydrate source, rice is gaining significant Hence, in the present review, extraction, characterization, - interest in terms of functional foods owing to the presence and application of aromatic compound have been eluci of aromatic compounds that impart health benefits by dated. These VACs can give a new way to food processing fl - lowering glycemic index and rich availability of dietary and beverage industry as bio avor and bioaroma com fibers. The demand for aromatic rice especially basmati pounds that enhance value addition of beverages, food, - rice is expanding in local and global markets as aroma is and fermented products such as gluten free rice breads. considered as the best quality and desirable trait among Furthermore, owing to their nutritional values these VACs fi consumers. There are more than 500 volatile aromatic com- can be used in bioforti cation that ultimately addresses the pounds (VACs) vouched for excellent aroma and flavor in food nutrition security. cooked aromatic rice due to the presence of aromatic hydro- Keywords: VACs, 2-AP, biofortification, Oryza sativa,nutra- carbons, aldehydes, phenols, alcohols, ketones, and esters. ceuticals, bioflavor The predominant VAC contributing to aroma is 2 acetyl-1- pyrroline, which is commonly found in aerial parts of the 1 Introduction Rice is the main staple food commodity after wheat and maize in many parts of the Asian countries, which is more * Corresponding author: Vinita Ramtekey, Department of Genetics than 90% global rice consumption rate [1]. Being an and Plant Breeding, ICAR-Indian Institute of Seed Science, important energy and nutrient source in the form of car- Kushmaur, Mau, Uttar Pradesh, 275103, India, bohydrate, rice is additionally known for its excellent e-mail: [email protected] * Corresponding author: Ashutosh Kumar, Department of sweet aroma. Among the various rice types, aromatic Microbiology, ICAR-Indian Institute of Seed Science, Kushmaur, rice received wider popularity in Asia and maximum Mau, Uttar Pradesh, 275103, India, e-mail: [email protected] acceptance in the East Asia, European countries, and Susmita Cherukuri, Sanjay Kumar: Department of Genetics and USA [2–4]. Aromatic rice cultivars have secured the prime - Plant Breeding, ICAR Indian Institute of Seed Science, Kushmaur, position in Indian and global market [5]. Its characteristics Mau, Uttar Pradesh, 275103, India such as pleasant, sweet aroma and superior grain quality Kaushalkumar Gunvantray Modha: Department of Genetics and ( ) - Plant Breeding, Navsari Agricultural University, Navsari, Gujarat, chemical and physical properties are the reasons for con 396450, India sumer preference, higher market value, and export rev- Udaya Bhaskar Kethineni: Department of Seed Science and enues [6–8]. The standard market price can improve the Technology, ICAR-Indian Institute of Seed Science, Regional Station, socioeconomic condition of farmers in developing countries GKVK Campus, Bengaluru, Karnataka, 560065, India such as India and Pakistan, which are involved in growing Govind Pal: Department of Economics, ICAR-Indian Institute of Seed Science, Kushmaur, Mau, Uttar Pradesh, 275103, India quality aromatic rice. There are a number of locally adapted Arvind Nath Singh: Department of Entomology, ICAR-Indian Institute small to medium size quality aromatic rice cultivars in Asian of Seed Science, Kushmaur, Mau, Uttar Pradesh, 275103, India countries with mild to strong flavor and fragrance [9–12] Open Access. © 2021 Vinita Ramtekey et al., published by De Gruyter. This work is licensed under the Creative Commons Attribution 4.0 International License. Extraction, characterization, and application of VACs from rice 273 due to the presence of volatile aromatic compounds (VACs). application of aromatic compounds. In the present review, These VACs were synthesized by different biochemical and we briefly discuss the aforementioned analytical techni- metabolic pathways [5,13,14]. ques for better understanding of aromatic compounds. In the literature, more than 500 aromatic compounds In the global market, prime role is played by aromatic have been reported and identified till date [15] in Asian aro- rice such as basmati and brown rice. This aromatic rice matic rice such as hydrocarbons, aldehydes, ketones, alco- has lesser glycemic index compared to white plain rice, hols, heterocyclic compounds, phenols, esters, and other which means slow release of energy that maintains the blood miscellaneous [5,16]. The principal compound for its sweet sugar level stable, thereby it can be utilized in diabetic diet fragrance is 2-acetyl-1-pyrroline (2-AP) heterocyclic chemical [40]. The studies on aromatic rice such as Kalanamak (black compound [17–19], which has close association with aro- rice) and brown rice show nutraceutical effects on human matic rice particularly Basmati and Jasmine rice varieties health in the form of richer source of dietary fibers, phenolics, from India and Thailand [20–23].The2-AP produces unique antioxidant property, proteins, vitamins, and minerals such “nutty-popcorn” aroma [5] and has shown the maximum as Fe and Zn [41–43].Theayurvedicmedicinalpropertyof flavor dilution factor among cultivated Asian rice varieties aromatic red rice includes higher polyphenols, anthocyanins, after quantification [24,25]. Previous studies suggested and antioxidant property [44]. This aromatic rice can be that there is a difference in the occurrence and quantity further improved to develop biofortified rice rich in Fe and of VACs contents concerning rice cultivars [12,26]. Zn to achieve food security and zero hunger [45].Thebypro- Different methods are available for extraction, character- duct of rice can be processed by value addition in terms of ization, and quantification of VACs. Traditionally purge and rice cake and rice bread (gluten free) are preferred more by trap [26], steam distillation (SD) using the Likens and Nick- northern India, and fermented products such as idli and dosa erson apparatus, solvent extraction (SE) method, SD coupled are preferred more by southern India, and Khanom jeen a with SE, and simultaneous distillation extraction (SDE) type of noodles has gained more attention in Korea [5]. method [18,21,26–28] were used for the extraction of VACs The VACs can be preferentially used by beverage from aromatic rice. Moreover, the main drawback of these industry to add aroma in the beverages such as rice wine, methodsisnon-automate and time-consuming processes which is preferred by the major part of China as traditional starting from sample preparation to final step for analysis alcohol drink. In germinated brown rice (GBR), higher as it depends on various organic solvents that affect the quantity of vitamins and gamma aminobutyric acid (GABA) aroma quantity and quality. Liyanaarachchi et al. [12] iden- is present [46]. This GABA helps in the reduction of hyper- tified different groups of VACs by performing SD and SE tension as well as neurotransmitter inhibitor in the central extraction protocol and suggested that SE is a more effi- nervous system [47]. So, the research can dig into more cient method for the extraction of aromatic compounds nutraceutical potential to develop GABA aromatic rice because it requires relatively lesser sample size and time. [48]. The consumption of GABA rice for a longer period To overcome the issues faced by conventional methods, of time can be useful in reduction of hypertension, pre- recently, analytical techniques such as solid-phase micro- venting high blood pressure and cardiovascular diseases extraction (SPME) with the advantage of gas chromato- [49]. The medicinal and nutrigenomic importance of graphy (GC) coupled with mass spectrometry (GC-MS) brown rice is due to the presence of phytochemicals, bioac- [29], flame ionization detector (GC-FID), nitrogen phos- tive compounds, and antioxidants that function as anti-dia- phorus detection (GC-NPD)[30,31], olfactory (GC-O), betic, anti-cholesterol, and cardio-vascular remission agents pulsed flame photometric detector (GC-PFPD)[32],head- [40]. By looking into the importance of GBR in nutritional space solid-phase micro extraction (HS-SPME) coupled and health benefits, the quality of GBR has been improved with GC-MS [33–35], and nuclear magnetic resonance using autoclave facility to maintain taste, aroma, grain tex- (NMR)[36] were adopted for rapid and efficient identifica- ture, and physiological ingredients [50]. There are reports on tion, extraction, characterization, and quantification of genetic and molecular markers linked to 2-AP and other VACs [24]. Turbo Matrix Headspace Trap coupled with volatile compounds related to BADH2 gene. This information GC-NPD and GC-MS analytical techniques is used for the can be harnessed to develop biofortified