ARTICLE INFO | ABSTRACT | |
ORIGINAL ARTICLE |
Background: Rosa damascena Mill. (Rosaceae) is a relevant ornamental and medicinal flower, whose distillation is known as Golab (Rosewater) in Iran. Due to the nature of the distillation process, methanol and ethanol are likely to be formed in the final product. Therefore, due to their toxicity, along with their frequent prescription, this study aims to investigate the concentrations of essential oil, methanol, and ethanol in commonly used brands of Rosewater available in Tehran, Iran. Methods: Methanol and ethanol concentrations were determined by gas chromatography, using a Flame Ionized Detector. Results: The mean essence level in the tested samples was 204.1 ± 18.0 ppm, which was significantly higher (P < 0.001) than the Iranian standard level. The mean methanol and ethanol levels in the tested samples were 1.25 ± 0.70 ppm and 700.0 ± 100.0 ppm, respectively, which were significantly lower than the maximum residues levels. Conclusion: The mean essence level in the tested samples well coped with the Iranian standard level. Moreover, there is no health risk to methanol and ethanol through Rosewater consumption.
Keywords: Rosewater; Essence; Methanol; Ethanol; Gas chromatography
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Article history: Received: 30 Sep 2021 Revised: 1 Dec 2021 Accepted: 1 Jan 2022 |
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*Corresponding author: saramohamadi12@yahoo.com Department of Food Hygiene and Quality Control, School of Veterinary Medicine, Shahre-kord University, Shahre-kord, Iran. Postal code: 8818634141 Tel: +98 383232440 |
Chemical tests to determine the essence value were carried out according to the Pantan method (ISO No. 1487) (Asemi et al., 2006). Also, 50 g of sodium chloride and 33 ml of pentane solution were added to 250 ml of the sample and stirred for 15 minutes. After the exhaust gases were released, the mixture was left stilled until two phases of water and oil were well separated. Then, the water phase discharged, and the amount of essence was calculated according to the weight difference, as shown in the following equation:
Table 1. The concentrations of essence, methanol, and ethanol of Rosewater samples. | |||
No. of samples | Essence content (ppm) | Methanol concentration(ppm) | Ethanol concentration (ppm) |
1 | 176.4 | ND | 140 |
2 | 131.0 | ND | 120 |
3 | 121.0 | ND | 400 |
4 | 55.0 | 20 | 1200 |
5 | 132.5 | ND | 800 |
6 | 205.6 | ND | 140 |
7 | 280.0 | ND | 250 |
8 | 159.0 | ND | 600 |
9 | 501.0 | ND | 50 |
10 | 121.0 | ND | 400 |
11 | 121.0 | ND | 80 |
12 | 120.0 | ND | 140 |
13 | 150.0 | ND | 460 |
14 | 120.0 | ND | 140 |
15 | 179.0 | ND | 550 |
16 | 309.2 | 8 | 250 |
17 | 217.0 | ND | 200 |
18 | 402.8 | ND | 2400 |
19 | 196.0 | 10 | 400 |
20 | 159.0 | ND | 115 |
21 | 120.0 | ND | 2000 |
22 | 243.0 | 7 | 750 |
23 | 301.0 | ND | 700 |
24 | 196.0 | ND | 1500 |
25 | 286.0 | ND | 1200 |
26 | 279.0 | ND | 2400 |
27 | 181.0 | ND | 2400 |
28 | 255.0 | ND | 250 |
ND; not detected |
Rosewater is a liquid obtained by hydro-distillation from fresh Rose flowers (Agarwal et al., 2005). It can be extracted using traditional (boiling petals) or industrial (steam distillation) methods (Nikbakht and Kafi, 2004). Rosewater frequently contains 10–50% Rose oil (Moein et al., 2014). Based on ISO (No. 1487), the minimum acceptable amount of Rosewater essence is 120 ppm. The mean essence level in the current study was 204.1 ± 18.0 ppm. In the study conducted by Rao et al., (Rajeswara Rao et al., 2000) on Rose flowers in three regions in India, the essential oil values were reported as 320, 340, and 500 ppm, respectively. In general, Rosewaters are classified into three types, including light (1 - 119 ppm), middle (120 - 350 ppm), and high (> 350 ppm) essence (Asemi et al., 2006). In this study, one sample out of 28 samples (or 3.5%) was categorized in light essence group (55 ppm), two samples (or 0.14%) were among the high essence group (501 and 402.8 ppm), while others (or 89.28%) were in the middle essence group.
Table 2. Comparison of the mean contents of essence, methanol, and ethanol with ISO standards. | |||
Variables | Mean content |
Standard error |
ISO (No. 1487) |
Essence (ppm) | 201.4 | 18 | > 120 |
Methanol (ppm) | 1.25 | 0.7 | < 100 |
Ethanol (ppm) | 700 | 100 | < 2500 |
ISO; Iranian standard organization |
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