Volatile oil profiling using GC‐MS of
Abstract
Specialty rice varieties with unique properties such as unique color, flavor, aroma and nutraceutical qualities are increasingly in demand other than the traditional white rice varieties. Black rice has various nutraceutical properties with high anthocyanin content and the anthocyanin antioxidants are very important in preventing various diseases. Black scented rice of Manipur, which are commonly known as Chakhao, are deep purple colored and scented, and are very glutinous, as well. Two Chakhao cultivars, Chakhao Poireiton and Chakhao Amubi, were shown to have high anthocyanin and phenolics content and strong antioxidant activity. The main anthocyanins of Chakhao Poireiton are delphinidin 3‐galactoside, delphinidin 3‐arabinoside, cyanidin 3‐galactoside and cyanidin 3‐glucoside and that of Chakhao Amubi are delphinidin 3‐galactoside, delphinidin 3‐arabinoside and cyanidin 3‐galactoside. By GC‐MS analysis, a cross mixture of 26 volatile compounds from Chakhao Poireiton and 11 volatile compounds from Chakhao Amubi were found to be responsible for emanating the aroma. Among the complex mixture of volatile oil components, n‐hexadecanoic acid and octadec‐9‐enoic acid were the most abundant in Chakhao Poireiton and 17‐pentatriacontene, l3‐octadecenal (Z) and hexadecenoic acid eicosyl ester in Chakhao Amubi.
Keywords
- black scented rice
- Chakhao rice
- Manipur
- anthocyanin
- nutraceutical properties
- flavor (Scent) active compounds
1. Introduction
Rice is the staple food for over half of the world's population. Rice cultivation provides employment for over one billion people directly or indirectly. Besides traditional white or common rice varieties, specialty rice varieties with unique properties such as unique flavor, aroma (unique aromas), color (red, purple), nutrition (glossiness, stickiness and smooth texture), chemical composition, esthetic, waxy (very low amylose content) and superior processing qualities are increasingly in demand. Rice according to the pericarp color can be broadly classified into black (purple), red and white rice. Black rice has high anthocyanin content located in the pericarp layers, which gives it a dark purple color [1, 2]. The demand for various types of specialty rice is increasing in recent years, which are sold for as much as 50% more than traditional rice cultivars [3]. Black rice has been used in various traditional medicines; recently, many researchers have reported that they have several health benefits in various studies, and thus, black rice is being considered as the new superfood by US scientists. In Asian countries, black rice is often consumed after mixing with white rice to enhance flavor, color and nutritional value, which includes high protein, total essential amino acids, vitamin B1 and minerals Fe, Zn, Mn and P, and it is intensely colored because of anthocyanin [4]. One serving of black rice even though contains some calories, but offers a high amount of flavanoid phytonutrients, important fiber, mineral content such as iron and copper, and it is a good source of plant‐based protein which is hard to get to plant‐based eaters who rely on grains and legumes for protein [5]. Black rice is rich in antioxidant anthocyanin [6, 7]. A spoonful of black rice bran provides the same amount or more anthocyanin than a spoonful of blueberries [8]. Anthocyanin antioxidants are very important in the prevention of cardiovascular disease, protection against cancer, improving brain function, reducing inflammation, etc [9, 10].
Flavor is the primary importance of specialty rice, and superior flavor increases consumer satisfaction and repeatedly purchase [11, 12]. Flavor is composed of taste and aroma, while aroma is conferred by volatile compounds emanating from cooked rice [13]. From cooked rice, a number of compounds have been identified, but only a few make up the characteristic aroma [9, 14, 15]. Based on the aroma, rice cultivars can be separated generally into aromatic and non‐aromatic types: Aromatic rice has a relatively diverse range of unique aromas [13] such as jasmine rice, which is characterized as having buttery, corn, dairy, starchy, cooked grain and nutty attributes, and basmati rice, which is characterized as having hay like and earthy attributes [16]. A complex mixture of odor‐active compounds comprises the aroma of both aromatic and nonaromatic rice; approximately 300 volatile compounds have been identified from various cultivars of aromatic and nonaromatic rice [17]; and several odor‐active compounds in cooked aromatic rice have been determined using odor units [18, 19]. In aromatic rice, 2‐acetyl 1‐pyrroline (2‐AP) is described as having a “popcorn‐like” odor by American and “pandan‐like” odor by Asian consumers which is synthesized in aerial parts of aromatic rice during growth, and in some nonaromatic types, it is present at a very low negligible concentration [20, 21]. 2‐AP is not only the compound responsible for the unique aromas, but their aromas are due to qualitative and quantitative variations in a diverse cross section of odor‐active compounds [13]. In cooked rice, lipid‐derived odor‐active compounds were formed during the degradation of oleic (octanal, heptanal, nonanal, (
Now, let us have a glance of Manipur, Manipur is a place of exquisite natural beauty and splendor. Manipur is a state of India laying on the northeastern corner of India bordering Myanmar (Burma). The state is rectangular in shape with a precious little valley in the center encircled by mountain ranges on all sides with salubrious climate [25]. The soil cover of Manipur can be divided into two broad types, viz. red ferruginous soil in hill area and alluvium in valley. Rice is the staple food for Manipuris. Agriculture mainly on rice and allied activities are the largest source of livelihood of majority of rural masses and backbone of the state's economy. Rice‐based agriculture and allied services provided direct employment to about 70% of the total working population of the state. Rice crop is commonly grown during
In this chapter, we reported the volatile oil components responsible for scent of two
2. Chakhao rice of Manipur
Manipur has a large variety of indigenous rice germplasm which range their adaptation from low‐lying lake areas to rainfed uplands of Manipur hills. There is a diverse set of locally adapted aromatic rice, ranging in color from white to red and purple, all of which are very glutinous in nature, also. They are commonly known as
The two great qualities of black scented rice of Manipur are their color and scent. These two great qualities make the
3. The two great qualities of black scented rice (Chakhao rice) of Manipur
3.1. Anthocyanin content and Nutraceutical properties of Chakhao
In our previous study [26], we had reported the anthocyanin and phenolics content and antioxidant activity of two black scented rice cultivars of Manipur,
Total phenolics content was estimated for
In our previous study, we had also reported the different types of anthocyanin present in Manipuris
In the present scenario, there is an increased interest in the alternative sources of anthocyanin due to a rising demand for economical sources of natural and stable pigments [33]. Anthocyanins have shown to be potent antioxidants which are superior to well‐known antioxidants such as butylated hydroxyanisole (BHA), alpha‐tocopherol, 6‐hydroxy‐2,5,7,8‐tetramethychromane‐2‐carboxylic acid (Trolox), catechin and quercetin [34]. Antioxidant capacity is becoming a parameter to characterize food or medicinal plants and their bioactive components. In the human body, dietary antioxidants protect against reactive oxygen species [35]. Anthocyanins may reduce the risk of cardiovascular diseases and cancer with anti‐inflammatory, antioxidant and chemoprotective properties [10], and also, if the antioxidants intake is increased, there may have a number of health effects, such as reducing the incidence of cancer and cardiovascular diseases [36]. Anthocyanins have been incorporated into the human diet, and due to their diverse physiological abilities to treat conditions such as hypertension, pyrexia, liver disorders, dysentery and diarrhea, urinary problems and the common cold, anthocyanins have been used as traditional herbal medicines [37]. Not only this, the dietary antioxidants can help to fight reactive oxygen species and free radicals and help to decrease the risk of chronic diseases such as coronary heart disease and certain cancers [38]. Our results showed that the black scented rice cultivars (
3.2. Volatile oil components for scent in Chakhao
A complex mixture of volatile compounds comprised the aroma of
Peak | R. Time | Name | Area | Area% |
---|---|---|---|---|
1. | 3.720 | Butanenitrile 3‐methyl | 104,009 | 0.25 |
2. | 4.540 | Benzene methyl | 2,295,838 | 5.61 |
3. | 6.873 | 2‐Furancarboxaldehyde | 1,393,622 | 3.41 |
4. | 11.768 | 2‐Furancarboxaldehyde 5‐methyl | 1,603,643 | 3.92 |
5. | 15.012 | Benzene butyl | 588,613 | 1.44 |
6. | 16.549 | Undecane | 289,797 | 0.71 |
7. | 16.765 | Benzofuran 2‐methyl‐3 | l8,639 | 0.78 |
8. | 18.310 | Benzene, pentyl | 31,571 | 1.30 |
9. | 18.943 | Furan 2‐(2‐furanylmethyl)‐5‐methyl | 619,648 | 1.51 |
10. | 19.660 | Dodecane | 649,180 | 1.59 |
11. | 20.133 | Benzofuran 4, 7‐dimethyl | 491,294 | 1.20 |
12. | 21.742 | Furan, 2,2'‐methylenebis[5‐methyl] | 649,017 | 1.59 |
13. | 27.782 | Pentadecane | 1,188,621 | 2.90 |
14. | 33.804 | Tetradecanoic acid | 781,382 | 1.91 |
15. | 37.940 | n‐Hexadecanoic acid | 9,379,913 | 22.92 |
16. | 41.112 | 9, 12‐Octadecadienoic acid (Z.Z) | 3,3l7,895 | 8.11 |
17. | 41.236 | Octadec‐9‐enoic acid | 4,771,521 | 11.66 |
18. | 41.317 | Oleic acid | l,336,655 | 3.27 |
19. | 48.343 | g‐Hexadecenoic acid octadecyl ester. (Z) | 1,588,616 | 3.88 |
20. | 48.818 | 9‐Hexadecenoic acid, eicosyl ester, (Z) | 1,535,517 | 3.75 |
21. | 49.042 | I 7‐Pentatriacontene z | 1,059,294 | 2.59 |
22. | 51.890 | 9‐Octadecenoic acid (Z)‐, 9‐octadecenyl ester, (Z) | 684,629 | 1.67 |
23. | 51.966 | 9‐Hexadecenoic acid. 9‐octadecenyl ester. (Z.Z) | 647,022 | 1.58 |
24. | 53.000 | 4‐Beta‐H‐Pregna | 3,591,642 | 8.78 |
25. | 53.419 | Stigmast‐5‐En.3‐oL. Oleat | 687,915 | 1.68 |
26. | 56.337 | Stigmast 5‐En‐3‐oL. (3.Beta.24S) | 818,755 | 2.00 |
40,924,254 | 100.00 |
GC‐MS analysis of the
Peak | R. Time | Name | Area | Area% |
---|---|---|---|---|
1. | 4.550 | Toluene | 748,852 | 3.38 |
2. | 37.880 | l‐(+)‐ascorbic acid 2,6‐dihexadecanoate | 490,0l1 | 2.21 |
3. | 48.618 | Cyclononasiloxane octadecamethyl | 346,471 | 1.56 |
4. | 49.428 | 9‐octadecenoic acid, 1,2,3‐propanetriyl ester, (E,E,E) | 427,185 | 1.93 |
5. | 49.635 | Z.Z‐3‐13‐octadecedien‐I‐o I | 434,892 | 1.96 |
6. | 50.685 | 9‐octadecenoic acid (Z)‐tetradecyl ester | 950,550 | 4.29 |
7. | 50.866 | l3‐octadecenal, (Z) | 2,667,664 | 12.03 |
8. | 51.096 | 9‐hexadecenoic acid. eicosyl ester (Z) | 2,655,953 | 11.98 |
9. | 51.241 | Tetracosamethyl‐cyclododecasiloxane | 2,277,003 | 10.27 |
10. | 51.682 | Z‐9‐pentadecenol | 2,169,969 | 9.79 |
11. | 55.156 | 17‐pentatriacontene | 9,001,555 | 40.60 |
22,170,105 | 100.00 |
Among the complex mixture of volatile oil components, n‐hexadecanoic acid and octadec‐9‐enoic acid were the most abundant compounds emanating the scent in
During the rice‐breeding program, evaluation of rice is done in many ways according to consumer desires and references. Some of the traits are easy to assess, while some are very difficult. Flavor assessment is one among the difficult traits. Assessment of flavor requires time, cost and traditional sensory panels which are not accurate and also limit the number of progeny. Thus, the study of volatile oil components of different
4. Conclusion
Nowadays, people are seeing forward more to the supplementation of natural antioxidant in the diet; thus, the consumption of pigmented rice will be a great thinking for the improvement in human health. Rice varieties with higher anthocyanin pigment have stronger scavenging activity than white rice varieties, and thus, these pigmented rice varieties are reducing agents and possess strong radical‐scavenging activity.
The approach of identification of individual rice aroma would make possible the selection of multiple flavor types and the development of superior new cultivars for a wide cross section of flavors without using sensory tests. The separation and characterization of these compounds may be of potential use in rice‐breeding programs focusing on flavor. A better understanding of the flavor (taste and aroma) of
Acknowledgments
The authors acknowledge Women Scientist Scheme A, Department of Science and Technology, Govt. of India (Reference No: SR/WOS‐A/LS‐632/2012(G)) for financial support for conducting the study.
References
- 1.
Ryu SN, Park SZ, Ho CT. 1998. High performance liquid chromatographic determination of anthocyanin pigments in some varieties of black rice. J Food Drug Anal. 6: 729–36. - 2.
Takashi I, Bing X, Yoichi Y, Masaharu N, Tetsuya K. 2001. Antioxidant activity of anthocyanin extract from purple black rice. J Med Food. 4:211–18. - 3.
Chaudhary RC. 2003. Speciality rices of the world: effect of WTO and IPR units production trend and marketing. J Food Agric Environ. 1:34–41. - 4.
Yang DS, Lee K, Jeong O, Kim K, Kays SJ. 2008. Characterization of volatile aroma compounds in cooked black rice. J Agric Food Chem. 56: 235–40. - 5.
Suzuki M, Kimura T, Yamagishi K, Shinmoto H, Yamaki K. 2004. Comparison of mineral contents in 8 cultivars of pigmented brown rice. Nippon Shokuhin Kagaku Kogaku Kaishi. 51: 424–27. - 6.
Dr. Axe. 2015. The Forbidden Rice: Black Rice Nutrition & Benefits. http://draxe.com/forbiddenrice/7/24/2015 . - 7.
Wolf M. 2015. Health benefits of black Rice. Demand Media, Jillian Michaels 7/25/2015. - 8.
Xu Z. 2010. Whole Grain Council, Black Rice Rivals Blueberries as antioxidant source, Louisiana State University Agricultural Center Study. Presentation at the National Meeting of the American Chemical Society, Boston MA. - 9.
Manach C, Scalbert A, Morand C, Remesy C, Jimenez L. 2004. Polyphenols: food sources and bioavailability. Am J Clin Nutr. 79(5): 727–4. - 10.
Park YS, Kim SJ, Chang HI. 2008. Isolation of anthocyanin from black rice ( Heugjinjubyeo ) and screening of its antioxidant activities. Kor J Microbiol Biotechnol. 36(1): 55–60. - 11.
Bhattacharjee P, Singhal R S, Kulkarni PR. 2002. Basmati rice: a review. Int J Food Sci Technol. 37: 1–12. - 12.
Suwansri S, Meullenet JF, Hankins JA, Griffin K. 2002. Preference mapping of domestic/imported Jasmine rice for U.S.‐Asian consumers. J Food Sci. 67: 2420–31. - 13.
Yang DS, Lee K, Kim K, Kays SJ. 2008. Site of origin of volatile compounds in cooked rice. Cereal Chem. 85(5): 591–8. - 14.
Grosch W, Schieberle P. 1997. Flavor of cereal products—a review. Cereal Chem. 74: 91–7. - 15.
Maga JA. 1984. Rice product volatiles: a review. J Agric Food Chem. 32: 964–70. - 16.
Limpawattana M. 2007. An integrated approach to sensory analysis of rice flavor. Ph.D. Dissertation, The University of Georgia, 2007. - 17.
Widjaja R, Craske JD, Wootton M. 1996. Comparative studies on volatile components of non‐fragrant and fragrant rices. J Sci Food Agric. 70: 151–61. - 18.
Buttery RG, Ling LC, Juliano BO. 1982. 2‐Acetyl‐1‐pyrroline: an important aroma component of cooked rice. Chem Ind (Lond). 12: 958–9. - 19.
Jezussek M, Juliano BO, Schieberle P. 2002. Comparison of key aroma compounds in cooked brown rice varieties based on aroma extract dilution analysis. J Agric Food Chem. 50: 1101–5. - 20.
Paule CM, Powers JJ. 1989. Sensory and chemical examination of aromatic and nonaromatic rices. J Food Sci. 54: 343–6. - 21.
Yoshihashi T. 2002. Quantitative analysis of 2‐acetyl‐1‐pyrroline of an aromatic rice by stable isotope dilution method and model studies on its formation during cooking. J Food Sci. 67(2): 619–22. - 22.
Monsoor MA, Proctor A. 2004. Volatile component analysis of commercially milled head and broken rice. J Food Sci. 69: 632–36. - 23.
Zhou Z, Robards K, Helliwell S, Blanchard C. 2002. Composition and functional properties of rice. Int J Food Sci Technol. 37: 849–68. - 24.
Nawar WW. 1996. Lipids. In: Fennema OR, Editor. Food Chemistry. Dekker: New York, pp. 225–319. - 25.
Singh RK, Baghel SS. 2003. Aromatic rices of manipur, a treatise on the scented rices of India (1st. ed.). New Delhi: Kalyani Publishers, p. 347. - 26.
Asem ID, RK Imotomba, PB Mazumder, JM Laishram. 2015. Anthocyanin content in the black scented rice ( Chakhao ): its impact on human health and plant defense. Symbiosis. 66: 47–54, doi: 10.1007/s13199‐015‐0329‐z. - 27.
Moko EM, Purnomo H, Kusnadi J, Ijong FG. 2014. Phytochemical content and antioxidant properties of colored and non colored varieties of rice bran from Minahasa, North Sulawesi, Indonesia. Int Food Res J. 21(3): 1053–59. - 28.
Wu L, Zhai M, Yao Y, Dong C, Shuang S, Ren G. 2013. Changes in nutritional constituents, anthocyanins, and volatile compounds during the processing of black rice tea. Food Sci Biotechnol. 22(4): 917–23. - 29.
Yodmanee S, Karrila TT, Pakdeechanuan P. 2011. Physical, chemical and antioxidant properties of pigmented rice grown in Southern Thailand. International Food Research Journal. 18(3): 901–6. - 30.
Muntana M and Prasong S. 2010. Study on total phenolic contents and their antioxidant activities of Thai white, red and black rice bran extracts. Pak J Biol Sci. 13(4): 170–74. - 31.
Xia X, Ling W, Ma J, Xia M, Hou M, Wang Q, Zhu H and Tang Z. 2006. An anthocyanin‐rich extract from black rice enhances atherosclerotic plaque stabilization in apolipoprotein E–deficient mice. J Nutr. 136: 2220–5. - 32.
Yawadio R, Tanimori S, Morita N. 2007. Identification of phenolic compounds isolated from pigmented rices and their aldose reductase inhibitory activities. Food Chem. 101: 1616–25. - 33.
Hu C, Zawistowski J, Ling WH, Kitts DD. 2003. Black rice ( Oryza sativa L.indica ) pigmented fraction suppresses both reactive oxygen species and nitric oxide in chemical and biological model systems. J Agric Food Chem. 51:5271–7. - 34.
Kahkonen MP, Heinonen M. 2003. Antioxidant activity of anthocyanins and their aglycones. J Agric Food Chem 51: 628–33. - 35.
Saenkod C, Liu Z, Huang J and Gong Y. 2013. Anti‐oxidative biochemical properties of extracts from some Chinese and Thai rice varieties. Afr J Food Sci. 7(9): 300–5. - 36.
Diplock AT, Charleux JL, Crozier‐Willi G, Kok FJ, Rice‐Evans C, Roberfroid M, Stahl W, Vina Ribes J. 1998. Functional food science and defence against reactive oxidative species. Brit J Nutr. 80:77–112. - 37.
Konczak I, Zhang W. 2004. Anthocyanins—more than nature's colours. J Biomed Biotechnol. 5: 239–40. - 38.
Abdel‐Aal E‐S, Abou‐Arab AA, Gamel TH, Hucl P, Young JC, Rabalski I. 2008. Fractionation of blue wheat anthocyanin compounds and their contribution to antioxidant properties. J Agric Food Chem. 56: 11171–77. - 39.
Champagne ET. 2008. Rice aroma and flavor: a literature review. Cereal Chem. 85: 445–54.