Comparative Study on Functional Components, Physicochemical Properties and Antioxidant Activity of Amaranthus Caudatus L. Oils Obtained by Different Solvents Extraction

: Functional compositions, physicochemical properties and antioxidant activities of Amaranthus caudatus L. oils (ACO) obtained by different solvents were comparatively investigated. All the resulted ACO were enrich in 75% unsaturated fatty acid and in squalene of about 4 g/100 g. Different solvents showed varying in oil extraction, where acetone results a highest yield of 6.80 g/100 g. ACO extracted by ethanol showed a highest tocopherol (1351.26 mg/kg), polyphenols (211.28 mg/kg) and squalene (42519.13 mg/kg). However, phytosterols in ACO extracted by hexane (27571.20 mg/kg) was higher than that by acetone (19789.91 mg/kg), ethanol (22015.73 mg/kg) and petroleum ether (24763.30 mg/kg). Furthermore, antioxidant activity of ACO was also measured by DPPH, ABTS and FRAP assay. According to principal component and correlation analysis, squalene was correlated with the DPPH scavenging ability, but phytosterols and tocopherols was correlated with the ABTS and ferric reducing ability of the oils, respectively. This study provides a promising excellent source of functional oil for food industries.

g/100 g crude fat, it is found that Amaranthus caudatus L. oil has unique nutritional characteristics e.g., vitamin E, polyphenols, sterols and other trace active components with a potential stronger antioxidant activity than ordinary oils 6,7 . Amaranthus caudatus L. oil contains among others linoleic acid up to 50 , tocopherols 802 mg/ kg , total sterols 2460 mg/100 g and squalene 4.16 g/kg of seed 8,9 . These components have shown remarkable antioxidant activity, benefits to nutrition and cardiovascular system health 10 . Efficient techniques had been used to recover oil from the plant resources, such as solvent extraction, pressing, subcritical extraction, supercritical fluid extraction, ultrasound-and enzyme-assisted extraction. Comparatively, solvent extraction provides efficient oil recovery, low-cost and low-energy consumption. In addition, both the extraction efficiency and oils activities were depended on the methods as well as the solvent used 11,12 . As we known, various compounds with different chemical characteristics and polarities have different solubility in a particular solvent 13 . There are several solvents such as water, ethanol, methanol, ethyl acetate, or hexane, among others for extracting compounds from fresh vegetable foods 14 . Conventional solvents as hexane are recognized for providing high extraction yields, but their use raises some safety, environmental and health issues; however, ethanol represents a safer alternative 15 . Furthermore, it was found that oil yield by ethanol extraction from avocado pulp were significantly lower than that obtained by petroleum ether, resulting in a high oxidative stability yet 12 .
Consolidation of sustainable technologies for Amaranthus caudatus L. oil extraction might increase the utilization of this high-quality oil. The objective of this study was to determine the physical and chemical properties, the fatty acids profile and the functional components of the oils extracted from Amaranthus caudatus L. seeds, obtained by four different extraction solvents. Moreover, the antioxidant capacity of Amaranthus caudatus L. oil was also systematically investigated, including DPPH radical scavenging ability, ABTS free radical scavenging ability and ferric reducing ability, to provide a theoretical basis for the development and research of functional Amaranthus caudatus L. oil in the future.

Physicochemical analysis of Amaranthus caudatus L.
Protein content N 6.25 was determined using a Kjeldahl nitrogen analyzer Kjeltec 8400, Foss, Sweden . Lipids, starch, crude fiber, moisture, and ash contents were examined according to official AOAC methods 16 .

Amaranthus caudatus L. oil extraction
Amaranthus caudatus L. seeds were firstly ground and then their oil was extracted according to the Soxhlet method AOAC 992.23 . The thimble containing the dried sample was placed in the Soxhlet device supporting with glass beads. The dehydrating beaker pre-dried for 1 h at 105 and weighed was rinsed with 150 mL of extractants e.g., petroleum ether, hexane, ethanol and acetone to the thimble. The samples were soaked overnight and refluxed for 8 h with a heat adjusted so the extractor siphoned at least 30 times. When the extraction was complete, the samples were air-dried at 70 to constant weight 1 h 12 . The oils obtained were cooled in desiccators and stored at 50 for less than two weeks until further analysis.
2.4 Physical and chemical properties of Amaranthus caudatus L. oil Physical and chemical properties including acid value AV , peroxide value, and sensory characteristics of Amaranthus caudatus L. oil obtained with the different extraction solvents were characterized according to the standard AOCS procedures 16 .

Fatty acid composition analysis
The fatty acid composition was determined according to the method proposed by Shi et al. 17 , after the conversion of fatty acids into fatty acid methyl esters FAME . The FAMEs analyses are carried out a 7890B Agilent gas chromatography interfaced with an Agilent 5977A mass selective detector Agilent Technologies, Palo Alto, CA, USA and a HP-88 MS column 100 m 0.25 mm 0.20 μm . Oven temperature was set initially at 140 for 5 min, programmed to increase at 4 /min to 240 with final holding time of 20 min. Helium 99.999 purity was used as carrier gas at a flow rate of 1 mL/min. The injection volume was 1 μL with an autosampler split ratio of 1:50. The MS conditions were: transfer line: 260 ; ion source: 250 ; collision energy: 35 eV; positive ionization mode. FAMEs were identified and quantified according to their retention times to both the standards and mass spectrometry MS .
2.6 High-performance liquid chromatography HPLC analysis of tocopherols Tocopherols were analyzed with the high-performance liquid chromatography HPLC according to the method of He et al. 18 , with some modifications. 500 mg of oils was mixed with 10 mL of hexane and syringe filtered 0.45 μm PTFE filter into a 2 mL of amber HPLC vials. Analysis of the tocopherols was performed on a Waters e2695 HPLC Waters, USA equipped with a Waters Spherisorb ® NH 2 analytical column 4.6 mm 250 mm, i.d. 5 μm and a RF-535 fluorescence detector Shimadzu . The injection volume was 20 μL and the oven temperature was 30 . The mobile phase was hexane/isooctane 98.5:1.5 v/v solution at a flow rate of 0.8 mL/min. Tocopherols were detected and quantified at 290 nm excitation wavelength and 330 nm emission wavelength, and identified by comparison of their retention factors with those of standards.

Determination of total phenolic compounds TPC
The TPC content was analyzed according to the Folin-Ciocalteu colorimetric method described by Can-Cauich et al. 19 , with some modifications. Briefly, 2 g of oil was mixed with 2 mL of an aqueous ethanolic solution 80 , v/v in distilled water . After shaking for 10 min, the mixture was centrifuged at 8,000 g for 5 min. Recovering the supernatant, the residue was subjected to further extraction in the same manner for additional three times. The supernatants obtained were pooled and quantitatived in a 10 mL flat volumetric flask. 10 μL of extracts were mixed with 150 μL of 6 Folin-Ciocalteu reagent and equilibrium for 3 min. Then, 50 μL of Na 2 CO 3 0.6 M was added to the extracts. The mixtures were mixed 600 rpm for 1 min and kept for 30 min in the dark. The absorbance readings of the mixtures were measured at 765 nm using an ultraviolet-visible UV-Vis spectrometer Pye Unicam Spectronic Camspec Ltd., Leeds, UK . The TPC content was expressed as mg gallic acid equivalents GAE /kg of oil.

Quantification of phytosterols and squalene by gas
chromatography-mass spectrometry GC-MS Phytosterols and squalene were simultaneous identified and quantified with a GC-MS technology. 0.25 g of oil sample was mixed with 3 mL of 2 mol/L KOH ethanol and 0.5 mL of 0.1 mg/mL internal standard 5α-cholestane in hexane. After the saponification, the mixture was mixed using a vortex mixer and incubated at 85 for 1 h in water bath. After cooling, 2 mL of distilled water and 5 mL of hexane were added, respectively. Subsequently, the clear upper layer was collected into a 50 mL centrifuge tube and washed twice with 5 mL of hexane each. All of the upper layers of extracts were combined and dried with nitrogen. After silylated with 0.2 mL of BSTFA TMCS at 70 for 40 min, the solution was filtered through a 0.45 μm filter. 1 μL of the filtered solution was injected into a Thermo Scientific gas chromatograph Thermo Fisher Scientific, CA, USA equipped with a HP-5MS column 30 m 250 mm 0.25 μm and a single quadrupole mass spectrometer ISQ; Thermo Fisher Scientific, CA, USA . Oven temperature was set at 285 . Helium was used as the carrier gas at a constant flow rate of 1.0 mL/min. The split ratio was 20:1. The mass spectrometer was operated in the electron impact mode at 70 eV with a scan range of 50-700 m/z. The temperatures of injector, transfer line and ion source were set at 280, 280 and 250 , respectively.

Antioxidant activity
The antioxidant activities of ACO were evaluated in terms of free-radical scavenging activity e.g., 2,2-diphenyl-1-picrilidrazil DPPH radical, 2,2 -azino-bis 3-ethylbenzothiazoline-6-sulfonic acid diammonium salt ABTS and ferric reducing ability FRAP . 2.9.1 DPPH radical scavenging capacity DPPH radical scavenging capacity was determined, following the procedure described by Chen et al. 20 , with some modifications. Briefly, 200 μL of sample were added into 3.8 mL of DPPH reagent 1.75 10 4 M in methanol and the mixture was placed in a dark room for 60 min. Subsequently, the absorbance was determined by UV spectrophotometer at 517 nm. The DPPH radical scavenging capacity was calculated and expressed as μmol Trolox equivalent TE per g in the sample. 2.9.2 ABTS radical scavenging assay ABTS scavenging activity was evaluated according to Can-Cauich et al. 19 . In brief, ABTS working solution 7 mM was prepared by dissolving 20 mg ABTS powder in 5.2 mL 2.45 mM potassium persulfate solution. The mixture was incubated in darkness at room temperature for 12 h, and then diluted with ethanol until an absorbance of 0.700 0.020 at 734 nm before use. Then, an aliquot of 20 μL samples was mixed with 280 μL diluted ABTS solution and incubated in the dark at room temperature for 6 min. The ABTS concentration in the mixture was measured at 734 nm by UV spectrophotometer. The ABTS free radical activity was computed and expressed as trolox equivalent antioxidant capacity TEAC . 2.9.3 Ferric reducing antioxidant power FRAP assay FRAP assay was evaluated measured according to Deetae et al. with minor modification 10 . Specifically, FRAP reagent contained 25 mL of acetate buffer 0.1 mol/L, pH 3.6 , 2.5 mL of TPTZ solution 10 mmol/L dissolved in 40 mmol/L HCl and 2.5 mL of FeCl 3 solution 20 mmol/L was daily prepared and warmed at 50 . The reactions were started by mixing 0.3 mL of methanolic extractions with 2.7 mL of FRAP reagent in a 10 mL volumetric flask. The blue solution was kept at room temperature for 10 min and then centrifuged at 3,000 rpm for 10 min. The absorbance was measured at 593 nm against a reagent blank using UV spectrophotometer and the reducing power of the sample was calculated, expressed as μmol Trolox equivalent TE per g of sample.

Statistical analysis
All analysis were performed in triplicate and results were reported as means standard deviations SD . Statistical analysis was performed using SPSS 20.0 by one-way analysis of variance ANOVA , and assessed by Duncan s multiple-range tests at p 0.05.

Results and Discussion
As a kind of medicinal and edible plant, Amaranthus caudatus L. is widely cultivated in China because of its high nutritional value 21 . The composition of Amaranthus caudatus L. seeds were as follows: 11.13 0.06 g/100 g moisture, 5.573 0.407 g/100 g fat, 43.440 0.085 g/100 g carbohydrates, 22.70 0.10 g/100 g protein, 0.6472 0.053 g/100 g ash, and 14.390 0.441 g/100 g crude fiber Table  S1 . Although the oil content in amaranth seed is only 5.6 g/100 g, Amaranthus caudatus L. oil ACO has been widely reported in deceasing blood cholesterol levels and used as traditional medicine to improve eyesight, facilitate excretion and dispel chills during the thousand s years in China 2,8 . Moreover, the Amaranthus caudatus L. contain more fat compared with grain amaranth that containing 4.37g oil per 100 g seed 22 , implying that it is a good resource for functional edible oil.

Amaranthus caudatus L. oil extraction yields
For the different solvents, the extraction yields were obtained by comparing the amount of extracted oil to the previously determined value of 5.57 fat. From Fig. 1, the highest extraction yield obtained with ethanol and acetone extraction solvents was 6.43 g/100 g and 6.80 g/100 g, respectively. This extraction yield was significantly p 0.05 higher than that of petroleum ether 5.30 g/100 g and hexane 4.36 g/100 g . In addition, according to the analysis of significance, there is no significant p 0.05 difference in the oil yield between acetone and ethanol, but there is a significant difference p 0.05 between the oil yield of petroleum ether or hexane and that of other solvents. This may be due to the fact that the formers can dissolve polar substances with a large amount of lipid accompanying microcomponents e.g., glycolipids and phospholipids, polyphenols, etc. , whereas petroleum ether and hexane do not dissolve polar substances, as can be seen from a higher clarity of the extracted ACO 16 .

Physical and chemical properties of ACO
The physical properties of the oils extracted with different solvents were shown in Table 1. According to the acid value AV , all the oils showed significant p 0.05 difference. Moreover, the oils extracted with ethanol and acetone showed a higher acid value; the oil extracted with hexane and petroleum ether had the lower values. These results agree with those reported by Moreno et al. 12 , who concluded that the acid value was related to the solvent polarity. Peroxide value POV is another important quality index because it is mandated by legislature and reflected appropriate processing conditions 23 . From the Table 1, such value was 200 of ACO obtained by the extraction of polarity either ethanol or acetone higher than of the samples obtained by hexane and petroleum ether. These values agree with the ones reported by Miraliakbari and Shahidi 24 . In this case, the oil extracted by petroleum ether had the lowest peroxide value of 1.07 0.07 mmol/ kg. On the senses, the oil extracted by hexane had a clearly golden color. Additionally, the oils extracted by hexane and petroleum ether are golden and clear, while the oils extracted by acetone and ethanol are dark green and turbid, and the oil extracted by ethanol is pasty. In addition to the sedimentation and turbidity observed in the oil extracted with acetone and ethanol, there is a possible presence of a greater amount of unsaponifiable material 10, 24 .

Fatty acid pro le of ACO
Fatty acid composition is an important identity characteristic of fat and oil, that is closely related to the stability and nutritional quality. The fatty acid composition of Amaranthus caudatus L. oils extracted from different solvents was identified through gas chromatography-mass spectrometer GC-MS , as also presented in Table 1. Seven types of fatty acids were identified through gas chromatography-mass spectrometer GC-MS . Linoleic 18:2 acid of 50 is the major fatty acid of ACO, followed by oleic acid 18:1 of 25 , palmitic 16:0 of 19 , and stearic 18:0 of 5 . Other fatty acids such as arachidic 20:0 and linolenic 18:3 acid were presented at levels below 1 while myristic acid C14:0 was only detected in trace amounts 0.2 . The ACO also contains oleic acid omega-9 which helps overcome cancer and also speeds wound healing 2 . In general, differences of the fatty acid proportions among the extracted oils were not significant p 0.05 , proving the types of solvent nonsignificant effect on the fatty acid composition. Significant differences p 0.05 were only found in the fatty acid content of C18:0 and C18:1. It was also found that the ACO followed the order: PUFA MUFA ≈ SFA. The fatty acid profiles of the oils extracted by hexane and acetone are very similar to the reported by Do et al. 11 . This is also in agreement with the results reported by others that the similar fatty acid profiles of lipid extracted from the same source material by using varying extractants e.g., petroleum ether, hexane and isopropanol was identical with the Soxhlet technique 25 . These results demonstrated that ACO should be encouraged because of its high amounts of functional fatty acids such as C18:1 and C18:2, which stimulated as a source of nutrients with benefits to consumers.

Effect of extraction solvent on the active components in ACO
Active substances, such as tocopherols, polyphenols, sterols and squalene, were natural biologically-active substances to delay the oxidation and affect the quality of oils. The contents of the trace active components vitamin E, sterol, squalene and polyphenol in ACO were determined respectively Table 2 . In the ACO, α-, β-, δ-tocopherol and α-tocotrienol were identified with the contents of 415.39-619.88, 303.76-575.98 and 51.35-104.89 mg/kg, respectively Fig. S1 . Meanwhile, the amounts of α-tocopherol, β-tocopherol and δ-tocopherol extracted by acetone and ethanol were higher than that extracted by hexane and petroleum ether. However, α-tocotrienol was only detected in the oil with the concentrations of 21.16-50.50 mg/kg, indicating that α-tocotrienol may be worked as a characteristic component in the ACO. The sum of tocopherol was 791. 76 10.53 mg/kg hexane , 952.00 20.70 mg/kg petroleum ether , 1050.05 13.06 mg/kg acetone and 1351.26 6.79 mg/kg ethanol . So, the contents of total tocopherol in the oil extracted by four solvents were as follows: ethanol acetone petroleum ether hexane. According to the literature, α-tocopherol is the most active ingredient in vitamin E, the biological activity was 100-folds than that of other tocopherols. The content of α-tocopherol in the oil extracted by four solvents was ethanol petroleum ether acetone hexane. This was especially the case for α-tocopherol, which is more effective in protecting vegetable oils against lipid oxidation 26,27 .
Six phytosterols, including campesterol, stigmasterol, Δ 7campesterol, β-sitosterol, Δ 7 -stigmastenol and Δ 7avenasterol, were found in the ACO, as shown the ion diagrams in Fig. S2. Total phytosterol content was ranged from 19789.91 41.61 to 27571.20 45.73 mg/kg. The total phytosterol is higher than those common vegetable oils such as soybean oil 250-362 mg/100 g , peanut oil 163-207 mg/100 g , sesame oil 595-865 mg/100 g and sunflower oil 298-451 mg/100 g reported in literatures 28   ly. Δ 7 -campesterol, Δ 7 -stigmastenol and Δ 7 -avenasterol were detected in the ACO with the amounts of 4506.36-7026.01 mg/kg, 3523.46-5697.92 mg/kg and 2365.19-3760.15 mg/kg, respectively. The comparison of the total phytosterol contents showed that the hexane and petroleum ether extraction system afforded oils with significance p 0.05 higher content. However, acetone-extracted ACO contained the lowest amount of phytosterols. The results about phytosterols were in agreement with previous reports 9, 29 . Total polyphenol concentrations in the ACO ranged from 11.31 2.87 to 211.28 6.26 mg/kg. Moreover, the polyphenol content in the ACO extracted by ethanol and acetone was higher than that extracted by petroleum ether and hexane. This may be due to the high polar of formers, resulting in a higher affinity to polar polyphenol. Squalene 2,6,10,15,19,23-hexamethyl-2,6,10,14,18,20-tetracosahexane is a triterpenic hydrocarbon precursor of vitamin D and cholesterol, and enriched in shark liver oil and some plant oils. As shown in Table 2, high squalene levels identified by GC-MS as shown in Fig. S3 in the ACO ranged from 39659.77 193.4 to 42519.13 69.61 mg/kg, which was remarkably higher that of olive oil 1100-8390 mg/kg and others edible oil e.g., walnut oil of 3.17-5.90 mg/kg, grapeseed oil of 88. 17 30 . Significance analysis found that there was no significant p 0.05 difference in squalene contents of ACO extracted by hexane and acetone; and there were significant p 0.05 differences among the others. One study demonstrated the ability of squalene to quench free radical oxygen molecules to revert to an unexcited state and thereby effectively prevent lipid oxidation 31 . Hence, ACO enrich in squalene would be an important foodstuff for a high nutritional 2 . Moreover, high squalene and phytosterols would also cause a good pull-in behavior and a good spreading ability to the skin s own lipids 32 . In summary, these plentiful trace active components of ACO may have significant benefit for antioxidation ability and oxidation stability.

Evaluating the antioxidant activity of ACO
Antioxidant capacity of ACO was also determined by free radical scavenging capacity assay using DPPH free radicals, ABTS radical scavenging assay and iron III reducing power ability. The results are presented in Fig. 2.
As shown in Fig. 2a, all of the ACO exhibited a very strong DPPH radical scavenging activity was remarkably 95 . Moreover, the results of DPPH scavenging capacity were also showed difference under different extraction methods. Specifically, the scavenging ability of the ACO extracted by petroleum ether, hexane and acetone was significantly p 0.05 higher than that of ethanol. It may be due to the trace active components Table 2 in the oils 30 . However, in the ABTS assay Fig. 2b , the highest value was found for ACO extracted by acetone and ethanol 495.45 0.45 μmoL/L Trolox and the lowest value was found for ACO extracted by petroleum ether 373. 18 2.73 μmoL/L Trolox . A similar pattern was found in the ferric reducing assay Fig. 2c : ACO extracted by ethanol had the highest value 5045.25 83.58 μmoL/L Trolox , and the lowest value was found for ACO extracted by petroleum ether and hexane 288.33 5.00 and 393.18 2.73 μmoL/L Trolox, respectively .
In comparison, higher DPPH and ABTS free radical scavenging capacity and ferric reducing ability were observed in the oils extracted by petroleum ether, hexane and acetone. The reason of the difference of the antioxidative ability was due to the difference of the trace amounts of natural antioxidants in these crude oils. Moreover, the difference antioxidant activities among the evaluated methods were due to their underlying different chemical mechanism and reflect different aspect of antioxidant properties 33 . For instance, DPPH method is more suitable for an assessment of the antioxidant capacity of lipophilic antioxidants instead of hydrophilic antioxidants. In contrast, ferric ion reducing method is more suitable for an assessment of the antioxidant capacity of hydrophilic substances instead of lipophilic antioxidants 34 . These results were also indicated the importance of using more radical scavenging capacity assays in the investigation of oil samples.

Correlations among antioxidant activity and phytochemical composition
Correlations between phytochemical compositions and antioxidant activity were evaluated and the results are showed in Table 3. It was noted that there is a significant r 0.981, p 0.05 negative correlation between the DPPH scavenging ability and squalene for ACO. The correlation between the ABTS scavenging ability and Δ 7avenasterol was negative significant r 0.963, p 0.05 . Furthermore, there was a significant correlation between ferric reducing ability and α-tocotrienol of ACO r 0.998, p 0.01 , followed by β-tocopherol and δ-tocopherol with a lower correlation of 0.970 and 0.968, respectively.
To quantify the relationships between antioxidant capacity in various antioxidant assays and minor components among different resulted oils, multivariate analysis of principal component analyses PCA were further performed. As illustrated in Fig. 3a, they could be reduced into two components PC1 and PC2 explaining 93.074 of total variance. Each component was responsible for 71.309 and 21.765 , respectively. The greater the absolute value of the load, the greater the influence. Therefore, PC1 was highly contributed by acid value, tocopherols, polyphenols and the ferric reducing ability, whereas PC2 was mainly positively correlated to phytosterols and squalene. The results agreed with the study on the relationship between radical scavenging activity and antioxidant activity reported by Bubonja-Sonje et al. 35 and Do et al. 11 , where reported that the minor components were related to the antioxi- It is noteworthy that the ACO extracted by four solvents processing were divided into three main clusters from a result obtained by a hierarchical cluster analysis HCA , as shown in Fig. 3b. The ACO extracted by petroleum ether and hexane were arranged into one group characterized by similarly low values of AV and POV with high phytosterol contents and DPPH scavenging ability. And the ACO extracted by acetone was divided into a cluster because of its high scavenging ability of DPPH and ABTS free radicals. However, the ACO extracted by ethanol was divided into Table 3 Correlations between phytochemicals and free radical scavenging capacity a  Polyphenols. Data were submitted to one-way analysis of variance (ANOVA), differences among groups were detected using multiple comparison procedures (Tukey post hoc test, p < 0.05). * Significant at p < 0.05, respectively. **Significant at p < 0.01, respectively. the third cluster. Therefore, the sample has the high AV, POV, tocopherol, polyphenol and squalene with high scavenging ability of ABTS free radicals and ferric reducing ability. These results were consistent with the data observed in PCA Fig. 3a .

Conclusion
Oils extracted by different solvents extraction from the seeds of Amaranthus caudatus L. native to China were systematic characterized. It was found that Amaranthus caudatus L. oil ACO was rich in 75 unsaturated fatty acid. Acetone resulted in a highest extraction yield of 6.80 g/100 g. Meanwhile, ACO extracted by ethanol showed significantly higher tocopherol, polyphenols and squalene than that of extracted from hexane, petroleum ether and acetone. Phytosterol content of the oils extracted by hexane was higher than that of acetone, ethanol and petroleum ether. Furthermore, antioxidant activity of oil was also measured by DPPH, ABTS and FRAP assay. According to both principal component and correlation analyses, squalene was correlated with the DPPH scavenging ability, phytosterols and tocopherols were correlated with the ABTS and ferric reducing ability of the oils, respectively. These results indicated that ACO had good quality and controllable functional from different solvents extraction, and highlighted the high potential resource in application of foods, medicines and cosmetics.