Effects of process parameters on the extraction efficiency and physicochemical characteristics of tea seed oil from “TRUNGDU” tea (Camellia sinensis O. Kuntze) variety

This research aimed at investigating the effects of extraction parameters on the extraction efficiency and chemical characteristics of Trungdu tea (Camellia sinensis O. Kuntze) seed oil, which is similar to olive oil with high portion of unsaturated fatty acids, especially essential linoleic acid and low content of saturated fat. The study parameters were particle size (0.25 - 2.00 mm), material/solvent ratio (1/12 - 1/6), temperature (25 - 55 oC), time (5 - 11 h), speed of solvent movement (0 - 250 r/m) and extraction times (1 - 3 times). The responses such as extraction efficiency, physicochemical characteristics (acid, peroxide, iodine and saponification values) were determined. The results indicated that the extraction efficiency was affected by all designed parameters. In addition, the temperature, particle size and extraction time had the most significant effect on the iodine value and acid value. The extraction temperature and the speed of solvent movement had pronounced effects on the acid, peroxide, iodine and saponification values of tea seed oil. However, ratio of material/solvent and extraction times did not appreciably affect on physicochemical characteristics of tea seed oil. Furthermore, the optimal extraction efficiency with higher quality attributes was achieved in the range of 35 to 45 oC, 7 to 9 hours, with a particle size of 0.5 mm, material/content ratio 1/8 to 1/12, movement speed of solvent 200 to 250 r/m and 2 times extraction. Therefore, the results from this work will be useful for developing an optimal procedure for obtaining tea seed oil. In addition, fatty acid composition of tea seed oil presented high content of oleic acid and linoleic acid, which warrants the high quality oil in terms of fatty acid profile.

Vietnam Journal of Science and Technology 57 (3B) (2019) 75-86 doi:10.15625/2525-2518/57/3B/14390 EFFECTS OF PROCESS PARAMETERS ON THE EXTRACTION EFFICIENCY AND PHYSICOCHEMICAL CHARACTERISTICS OF TEA SEED OIL FROM “TRUNGDU” TEA (Camellia sinensis O Kuntze) VARIETY Phan Thi Phuong Thao1, 2, *, Tran Thi Thu Hang2, Hoang Dinh Hoa1, Vu Hong Son1 Hanoi University of Science and Technology, No Dai Co Viet, Hai Ba Trung, Ha Noi Vietnam National University of Agriculture, Trau Quy, Gia Lam, Ha Noi * Email: phanphuongthao@vnua.edu.vn Received: September 2019; Accepted for publication: November 2019 Abstract This research aimed at investigating the effects of extraction parameters on the extraction efficiency and chemical characteristics of Trungdu tea (Camellia sinensis O Kuntze) seed oil, which is similar to olive oil with high portion of unsaturated fatty acids, especially essential linoleic acid and low content of saturated fat The study parameters were particle size (0.25 - 2.00 mm), material/solvent ratio (1/12 - 1/6), temperature (25 - 55 oC), time (5 - 11 h), speed of solvent movement (0 - 250 r/m) and extraction times (1 - times) The responses such as extraction efficiency, physicochemical characteristics (acid, peroxide, iodine and saponification values) were determined The results indicated that the extraction efficiency was affected by all designed parameters In addition, the temperature, particle size and extraction time had the most significant effect on the iodine value and acid value The extraction temperature and the speed of solvent movement had pronounced effects on the acid, peroxide, iodine and saponification values of tea seed oil However, ratio of material/solvent and extraction times did not appreciably affect on physicochemical characteristics of tea seed oil Furthermore, the optimal extraction efficiency with higher quality attributes was achieved in the range of 35 to 45 oC, to hours, with a particle size of 0.5 mm, material/content ratio 1/8 to 1/12, movement speed of solvent 200 to 250 r/m and times extraction Therefore, the results from this work will be useful for developing an optimal procedure for obtaining tea seed oil In addition, fatty acid composition of tea seed oil presented high content of oleic acid and linoleic acid, which warrants the high quality oil in terms of fatty acid profile Keywords: tea seed oil, extraction parameters, efficiency, physicochemical characteristics Classification numbers: 1.3.1, 1.4.5 INTRODUCTION Tea is native to East Asia and probably originated in the borderlands of north Burma and southwestern China Tea is an evergreen shrub around the year [1] After water, it is the most widely consumed drink in the world [2] Today many countries in the world have used tea seeds Phan Thi Phuong Thao, Tran Thi Thu Hang, Hoang Dinh Hoa, Vu Hong Son to produce cooking oil, herbal medicines such as Germany, China, Japan, India [3] Tea and its products have become increasingly popular recently In China, over a million tons of tea seed were produced each year [4] The rapid increase for seed co-produced raised the challenge of finding suitable commercial applications That explains why there are many research groups working on tea seed products for the development of this key industry Like other genera of Camellia (from Theaceae family), tea seeds are rich in oil (30–32 %) [5] Tea seed oil is stable and suitable in nutritional properties, has a shelf life value identical to that of the olive oil at a temperature of 63 °C, has higher shelf life than that of sunflower oil, and is capable of increasing the shelf life of sunflower oil when mixed [6] Tea (C sinensis) seed oil is highly edible and equally important as a health-promoting food resource in the human diet due to its good antioxidant activity [1] Tea seed oil comprises of essential monoene and can be a suitable feedstock for inedible applications, which may include surfactant production, biodiesel and lubricants, biopolymers, etc., hence can serve as an alternative to petrochemicals, which are limited in supply [7] Moreover, tea seed oil contains high amount of unsaturated fatty acids [1], especially linoleic acid, which is reported to lower blood cholesterol levels [8] It also has a minute amount of linolenic acid, which is an important factor in rancidity and off-flavor of oils during storage [9] Essential fatty acids are necessary for the human diet for the maintenance of growth and reproduction [10] Thus, using tea seeds as a source of edible oil has been suggested as source of essential fatty acids, which would otherwise be a waste product Some variables have been reported to have effects on the extraction efficiency and chemical characteristics of tea seed oil when extracted using solvent method such as: tea seed clone type, solvent type, particle size, material/solvent ratio, extraction temperature, extraction time, speed of solvent movement, extraction cycle In this research using solvent extraction method, the effects of some extraction parameters: particle size, ratio of material/solvent, extraction temperature, extraction time, speed of solvent movement, extraction cycle on the efficiency and chemical characteristics of “Trungdu” tea seed oil were investigated MATERIALS AND METHODS 2.1 Tea seeds Tea seeds were harvested from mature tea plants of “Trungdu” tea variety (Camellia sinensis O Kuntze) in Phu Tho province, Vietnam in December 2017 The healthy tea seeds were dried in ambient conditions to - 10 % moisture and then manually de-husked The desired tea seed kernels were then milled using an electric blender (Philips HL7510/00, Netherlands) for particle size reduction and test sample homogenization 2.2 Experimental design Parameters were particle size (0.25 - 2.00 mm), solid-solvent ratio (1/12 - 1/6), temperature (25 - 55 oC), time (5 - 11 h), speed of solvent movement (0 - 250 r/m) and extraction times (1 - times) The responses such as extraction efficiency, physicochemical characteristics (acid, peroxide, iodine and saponification values) were determined 2.3 Analytical methods 2.3.1 Oil content (OC) 76 Effects of process parameters on the extraction efficiency and physicochemical characteristics… This was determined by expressing the mass of the oil extracted as a percentage by mass of the oil-bearing material (milled seeds) minus the moisture content of the seed used in the extraction [11] 2.3.2 Determination of extraction efficiency Extraction efficiency is the percentage of oil extracted in relation to the amount of oil present in the seed Oil extraction efficiency was computed as the ratio of the weight of oil recovered (Wor) to the product of the seed oil content (Soc) and weight of crushed seed sample (Wcss) before extraction It was mathematically stated as shown in the formula: ( ) 2.3.3 Determination of acid value (AV) This was determined according to AOCS Official Method Cd 3d-63 [12] The acid value is defined as the number of milligrams of potassium hydroxide required to neutralize the free fatty acids present in one gram of fat Weigh, to the nearest mg, - 10 g well-mixed sample into 250 300 ml Ether etylic Add 50 - 100 ml alcohol-ether mixture and 0.1 mL phenolphthalein solution Titrate with 0.1 N alcoholic KOH until permanent faint pink appears and persists for ≥ 10 s AV = where: V: ml alcoholic KOH solution, f: concentration adjustment coefficient KOH 0.1 N (f = 1), c: Weight of sample (g), 5.61: grams of KOH contained in ml of KOH 0.1 M Difference between duplicate determinations should be ≤ 0.1 mg KOH/g fat 2.3.4 Determination of iodine value (IV) This was determined according to Wijs as indicated by AOCS Official Methods of Analysis Cd 1-25 [13] using the formula: ( IV = ) and the results were expressed as g I2/100 g of oil, where; m is the weight (g) of oil, V is the volume (ml) of Na2S2O3 used in the test, v is the volume (ml) of Na2S2O3 used in the blank and T is the concentration of Na2S2O3 (mol/l) and 126.9 the atomic mass of iodine 2.3.5 Determination of saponification value (SV) This was determined according to AOCS method Cd 3-25 [14] with slight modifications About g of oil was weighed into a 250 ml round bottom flask Using a volumetric flask, 50 ml of 0.5 M ethanol KOH was added to the sample The mixture was boiled under reflux for h The hot soap solution was then titrated with 0.5 M HCl using phenolphthalein indicator A blank was also run in the same manner The saponification values were calculated using the formula: SV = ( ) and reported in mg KOH/g oil, where, 56.1 is the molecular weight of KOH, m is the weight (g) of fat, V1 is the volume (ml) of HCl used in the sample, V2 is the volume (ml) of HCl used in the blank and c is the concentration (mol/l) of HCl 77 Phan Thi Phuong Thao, Tran Thi Thu Hang, Hoang Dinh Hoa, Vu Hong Son 2.3.6 Determination of peroxide value (PV) This was determined according to the IUPAC method 2.501 [11] with slight modifications Approximately g of oil was weighed into a flask Twenty milliliters (20 ml) of solvent (2:1 v/v, glacial acetic acid: chloroform) was added to the sample followed by ml of freshly prepared saturated KI solution A homogenous solution resulted After a few minutes, 30 ml of water was added and the mixture titrated with sodium thiosulphate solution (0.01 M) with starch solution as the indicator The peroxide values were calculated using the equation: PV = ( ) and reported in meq O2/kg oil, where: m is the weight (g) of oil, V1 is the volume (ml) of Na2S2O3 used in the test, V2 is the volume (ml) of Na2S2O3 used in the blank and N is the concentration of Na2S2O3 (mol/l), f: concentration correction factor 2.3.7 Determination of fatty acid content A gas chromatography-flame ionization detector (GC-FID) according to the Ce 1-62 Method of American Oil Chemists’ Society [15] determined the fatty acid composition of the tea seed oil Oil samples were converted to methyl esters by vigorous shaking of the oil solution in ml n-hexane with ml of methanol potassium hydroxide The tube holding the solution was placed in a water bath (60 °C) for 20 and was shaken for hour After decanting during the final min, μl of the upper layer was injected into the GC-FID (6890 N, Agilent, US) equipped with a DB-225 capillary column (30 m × 0.25 mm x 0.25 μm) under the following conditions: initial temperature = 35°C (1 minute)  180 oC (20 °C/min), final temperature = 220 °C (35 minutes), heating rate = 20 °C/min, detector temperature = 260 °C, injector temperature = 250 °C, pressure of nitrogen (carrier gas) = 42.12 psi wx  Ax 100  M At  100 where: wx: relative mass fraction of component x (g/100 g); Ax: the area of the peak corresponding to the component x (used area units); At: the total corrected area of all peaks, excluding the solvent peak (used area units); M: the lipid content (g/100 g of seed) 2.4 Data analysis Data obtained were subjected to analysis of variance (ANOVA) using Minitab statistical package version 16 at p ≤ 0.05 The least significant difference (LSD) test was used in mean separation where statistically significant differences were recorded Data are tabulated as means of triplicate determinations ± standard deviation (SD) RESULTS AND DISCUSSION 3.1 Effect of particle size on extraction efficiency and physicochemical characteristics of tea seed oil It was observed that as the particle size increased (0.25 to mm), extraction efficiency decreased from 87.96 % to 71.86 % as shown in Table The smaller particle size gave more efficiency because of the higher surface area to volume ratio that in turn enhanced the contact between the solvent molecules and tea seed particles during the extraction process [1] When the 78 Effects of process parameters on the extraction efficiency and physicochemical characteristics… size of the particle is small, it results in relatively large surface area, hence increasing the contact area in between the solvent [16] Size reduction also helps for easier accessibility of the soluble substrates that are otherwise located deep inside the plant matrix [4] Table Effect of particle size on extraction efficiency and physicochemical characteristics of tea seed oil Particle size (mm) Extraction efficiency (%) AV (mg KOH/g) PV (meq/kg) IV (gI2/100g) SV (mg KOH/g) 0.25 87.96a ± 0.03 2.61a ± 0.12 4.71a ± 0.39 89.60b ± 1.03 164.30c ± 4.45 0.50 87.79a ± 0.07 2.67a ± 0.23 4.54a ± 0.59 100.62a ±1.34 202.23a ± 5.95 1.00 81.36b ± 0.05 3.46b ± 0.06 4.67a ± 0.31 98.80a ± 0.89 204.56a ± 4.72 1.50 76.23c ± 0.24 3.51b ± 0.18 5.43ab ± 0.32 80.13c ± 3.14 209.46a ± 6.15 2.00 71.86d ± 0.01 5.42c ± 0.23 5.90b ± 0.12 69.23d ± 2.52 182.78b ± 7.45 Numbers followed by the different letter in the same column are significantly different at 0.05 levels The highest extraction efficiency (87.96 %) was obtained at the particle size of 0.25 mm, but this had no statistically significant difference from that achieved at the particle size of 0.5 mm It was also shown that, the lowest acid value achieved at 0.25 mm, but there was no significant difference from that at 0.50 mm, which were lower than the standard values of Codex standard for vegetable oils (the maximum level of the acid value for pure oils is 4.0 mg KOH/g) [17] The number of peroxides present in edible fats and oils is an index of their primary oxidative level In fact, the lower the peroxide value, the better the fat or oil quality and its status of preservation [18] The peroxide value of tea seed oil was determined as 4.71 to 5.90 (meq/kg) That means the particle size does not cause much change in the peroxide value, especially, there was no significant difference in the PV between 0.25, 0.50, 0.10, 1.50 mm In comparison with the standard values of Codex Standard (the maximum PV for pure oil is 15 meq/kg), it can be seen that the PV of all variables are lower than that [17] The iodine value was found to relatively decrease with increasing the particle size, the highest IV (100.62 gI2/100 g) obtained at the size of 0.5 mm Generally, the IV from this work is higher than the one of C sinensis seed oil reported by Yahaya (74.23 gI2/100 g) [7] It is also higher than the IV of palm oil (50 - 55 gI2/100 g), and equivalent to the one of peanut oil (86 107 gI2/100g) [17] Several studies have shown that the concentration of oleic acid in tea seed oil is higher than linoleic and linolenic [1,7] Monounsaturated fatty acid in tea seed oil is more than polyunsaturated fatty acid, hence probably a reason for its lower IV compared to other oil, which is more polyunsaturated [19] The fatty acid composition of the triacylglycerol greatly influences this parameter Higher saponification values are indicative of the presence of lower molecular weight compounds/ short chain fatty acids in the oil Higher saponification values are more desirable when considering oil for the soap industry However, it is undesirable in the production of biodiesel The result presented in Table shows no significant differences in SV between the particle size of 0.5, 1.0, 1.5 mm Some oils extracted from these solvents also concur with a study that shows no significant differences in SV of tea seed oil (Indian), sunflower and olive 79 Phan Thi Phuong Thao, Tran Thi Thu Hang, Hoang Dinh Hoa, Vu Hong Son oils [20] Thus, the difference of particle size only has a slight effect on the extraction efficiency of tea seed oil The average SV of tea seed oil from this work is equivalent to the value reported by Yahaya (186.5 mgKOH/g of oil) [7] When the size is small, observing the tea seed powder is too smooth, causing sticking much on the grinding device, when filtering the filter speed lower, it causes more time Thus, the appropriate size was 0.5 mm 3.2 Effect of the material/solvent ratio on extraction efficiency and physicochemical characteristics of tea seed oil Table Effect of the material/solvent ratio on extraction efficiency and physicochemical characteristics of tea seed oil Material/solve nt ratio Extraction efficiency (%) AV (mg KOH/g) PV (meq/kg) IV (gI2/100g) SV (mg KOH/g) 1/6 70.06b ± 1.41 2.26a ± 0.14 5.98b ± 0.36 90.95a ± 3.84 187.12a ± 7.91 1/8 73.70b ± 3.14 2.51a ± 0.19 5.27ab ± 0.30 93.18a ± 6.79 189.1a ± 7.57 1/10 87.76a ± 0.51 2.67a ± 0.23 4.54a ± 0.59 91.86a ± 9.23 186.42a ± 9.43 1/12 89.77a ± 1.35 3.41b ± 0.1 4.57a ± 0.21 93.62a ± 9.55 188.84a ± 4.75 Numbers followed by the different letter in the same column are significantly different at 0.05 levels From Table 2, it can be seen that as the material/solvent ratio increased (1/6 to 1/12), the extraction efficiency of tea seed oil increased from 70.06 % to 89.77 % The larger the ratio of material to solvent, the higher the extraction efficiency However, there was no significant difference in the extraction efficiency between the ratio of 1/10 and 1/12 As the ratio of material to solvent increases, the amount of solvent used increases and the contact between oil and solvent is more The movement between them is more intense and the oil is more likely to spread However, the amount of tea seed is certain Once the saturation state is reached, the amount of oil extracted also reaches a certain level, and the extraction rate tends to be stable From the ANOVA result in Table 2, it can be seen that the material/solvent ratio did not appreciably effect on chemical characteristics of tea seed oil, especially, there was no significant difference in IV and SV in the operating condition ranges selected in the experiment Material: solvent ratio from 1/8 to 1/12 was suitable for the extraction of tea seed oil 3.3 Effect of temperature on extraction efficiency and physicochemical characteristics of tea seed oil Table indicates that the extraction efficiency was directly proportional to the extraction temperature The reason is the higher temperature accelerates the movement of particles and solvent molecules, and then makes the dissolved oil more However, from Table 3, it can be seen that the average extraction efficiency remains the same at about 90 % as the temperature increases from 40 to 55 oC (no statistically significant differences at 0.05 levels) Furthermore, high temperature may promote epimerization, oxidation, and degradation reaction of nutraceutical compounds This result is in agreement with the values reported by Zarringhalami, which stated that the extraction temperature using petroleum solvent is 40–60 oC [21] It is also 80 Effects of process parameters on the extraction efficiency and physicochemical characteristics… generally similar to the results from Yang-Lin and Aijun, with the optimum temperature for extraction of tea seed oil is 40 oC [22, 23] Table Effect of temperature on extraction efficiency and physicochemical characteristics of tea seed oil Extraction temperature (0C) 25 30 35 40 45 50 55 Extraction efficiency (%) AV (mg KOH/g) PV (meq/kg) IV (gI2/100g) SV (mg KOH/g) 76.03e ± 0.05 1.80a ± 0.01 4.30a ± 0.10 75.57c ± 0.93 151.14d ± 9.68 82.91d ± 0.05 2.11a ± 0.04 4.37a ± 0.16 85.88b ± 3.68 170.93c ± 2.83 87.79c ± 0.07 89.7b ± 0.53 90.15ab ± 0.1 90.38a ± 0.05 90.73a ± 0.05 2.67a ± 0.23 3.02a ± 0.09 5.27b ± 0.19 6.16b ± 0.40 7.53c ± 1.17 4.54a ± 0.59 5.07ab ± 0.12 5.78bc ± 0.29 6.29c ± 0.31 9.38d ± 0.20 100.62a ± 1.34 98.08a ± 1.05 86.84b ± 1.79 74.37c ± 2.29 66.98d ± 0.62 202.23a 211.82a 207.22a 186.45b 166.92c ± 5.95 ± 2.41 ± 2.04 ± 4.65 ± 2.44 Numbers followed by the different letter in the same column are significantly different at 0.05 levels The acid value was considered in the food industry as an indicator of the quality of the oil and the degree of its degradation during heating An increase in the acid value leads to the development of unpleasant tastes and odors in oils The increase in acid value attributed to the hydrolysis of TAG (triacylglycerol) and/or cleavage and oxidation of fatty acid double bonds [24] Table illustrates that the effect of extraction temperature on AV and PV followed the same trend Both the AV and PV were found to increase with increasing the extraction temperature from 25 to 55 oC This demonstrates that increased temperatures have caused an increase in oxidation and decomposition of tea seed oil This trend in acid value agrees with the trend reported in Jatropha oil and seem oil extractions respectively [25] However, there was not significantly different in the ones as the temperature increased from 25 to 40 oC These results indicated that relatively lower temperatures are desirable to obtain lower acid values in tea seed oil Besides, both the IV and SV increased as the temperature increased from 25 to 40 oC where they reached a plateau before decreasing from 45 to 55 oC The highest values of IV and SV were all recorded at 40 oC From 35 to 45 oC was the temperature range for extraction efficiency and high tea seed oil quaility 3.4 Effect of time on extraction efficiency and physicochemical characteristics of tea seed oil Table Effect of time on extraction efficiency and physicochemical characteristics of tea seed oil 72.00b ± 2.04 AV (mg KOH/g) 2.48a ± 0.32 87.76a ± 0.51 2.67a ± 0.23 4.54a ± 0.59 91.86a ± 9.23 186.42a ± 11.43 89.58a ± 1.03 3.37b ± 0.12 4.18a ± 0.64 92.64a ± 6.59 187.03a ± 5.50 Extraction time (hours) Extraction efficiency (%) PV (meq/kg) IV (gI2/100g) SV (mg KOH/g) 5.09b ± 0.26 91.79a ± 5.62 184.5a ± 9.55 11 90.15a ± 0.78 3.49b ± 0.12 4.84ab ± 051 93.37a ± 4.90 188.37a ± 10.78 Numbers followed by the different letter in the same column are significantly different at 0.05 levels 81 Phan Thi Phuong Thao, Tran Thi Thu Hang, Hoang Dinh Hoa, Vu Hong Son The results tabulated in Table revealed that the extraction efficiency of tea seed oil increased as the extraction time increased from to 11 hours and reached the highest efficiency (90.15 %) at 11 hours However, from the ANOVA result, there were no statistically significant differences in the extraction efficiency between the duration of 7, and 11 hours The extraction efficiency of tea seed oil increased with the duration linearly because for longer duration the particle and solvent will be in contact and thus the particles release more oil However, after hours the variance noted was not significant as shown in Table It might be because diffusion of oil was fast due to high initial oil content This diffusion rate decreased significantly when the oil content of sample decreased From the ANOVA result in Table 4, it was also shown that the extraction time had an appreciable effect on AV, PV, but it did not significantly affect the IV and SV of tea seed oil Specifically, the AV increases from 2.48 to 3.49 mg KOH/g as the extraction time increase from to 11 hours, but there are no significant differences in AV between the time of 5, hours and between 9, 11 hours In addition, the PV does not significantly affect as the time increase from to 11 hours This indicates that extraction temperature tends to have more effects on the chemical characteristics compared to time Besides, prolonged extraction time resulted in decomposition of oil, nutraceuticals and in solvent loss through evaporation, thereby affecting mass transfer loss during extraction [26] Therefore, taking into consideration that extraction time is crucial in economizing extraction process cost, the optimal extraction time was selected to be to hours 3.5 Effect of the speed of solvent movement on extraction efficiency and physicochemical characteristics of tea seed oil Table Effect of speed of solvent movement on extraction efficiency and physicochemical characteristics of tea seed oil Speed of solvent movement (r/m) Extraction efficiency (%) AV (mg KOH/g) PV (meq/kg) 62.76f ± 0.07 6.12d ± 0.13 50 70.95e ± 0.09 100 77.4d ± 0.09 IV (gI2/100g) SV (mg KOH/g) 8.16d ± 0.20 59.88d ± 0.63 113.69c ± 3.18 5.35c ± 0.13 6.19c ± 0.20 61.80d ± 1.92 134.84c ± 4.64 5.02bc ± 0.53 5.33b ± 0.12 67.30c ± 0.68 175.45b ± 9.05 150 81.73c ± 0.01 4.33b ± 0.12 4.80ab ± 0.20 83.00b ± 0.67 193.82ab ±11.22 b a a a 200 87.79 ± 0.07 2.67 ± 0.23 4.54 ± 0.59 100.62 ±1.34 202.23a ± 5.95 a a a a 250 89.77 ± 0.60 2.40 ± 0.19 4.39 ± 0.07 100.30 ±2.28 202.62a ± 13.79 Numbers followed by the different letter in the same column are significantly different at 0.05 levels As illustrated in Table 5, the speed of solvent movement does affect the extraction efficiency significantly (p < 0.05) As the speed of solvent movement increased, the extraction efficiency of tea seed oil increased continuously The highest efficiency obtained at the speed of 250 r/m This was explained that the increasing in speed of solvent movement results in an increment in solubility and diffusion due to increase in surface area available for mass transfer between the particle and solvent, thereby enhancing the extraction efficiency 82 Effects of process parameters on the extraction efficiency and physicochemical characteristics… The result presented in Table show that the speed of solvent movement had pronounced effects on all the AV, PV, IV and SV of tea seed oil Specifically, as the speed of solvent movement increased from to 250 r/m, both the AV and PV decreased gradually while the IV and SV increased gradually Moreover, the lowest AV and PV achieved at the speed of 200 and 250 r/m and the highest IV and SV also obtained at the speed of 200 and 250 r/m Thus, 200 to 250 r/m was the approximate movement speed of solvent for tea seed oil extraction 3.6 Effect of extraction times on the efficiency and physicochemical characteristics of tea seed oil Table Effect of extraction times on the efficiency and physicochemical characteristics of tea seed oil Extraction times Extraction efficiency (%) 87.76b ± 0.51 AV (mg KOH/g) 2.67a ± 0.23 PV (meq/kg) 4.54a ± 0.58 IV (g I2/100 g) 91.86a ± 9.23 SV (mg KOH/g) 186.42a ± 11.43 89.59ab ± 2.07 2.94a ± 0.19 5.27a ± 0.25 92.71a ± 5.69 185.77a ± 8.60 90.94a ± 0.66 3.8b ± 0.29 5.46a ± 0.14 93.98a ± 6.58 185.25a ± 4.88 Numbers followed by different letter in the same column are significantly different at 0.05 levels To assess the influence of multiple extraction times, all the above optimal extraction parameters were used to determine the effect of a single, double, and triple extraction times on the efficiency and chemical characteristics of tea seed oil As can be seen from Table 6, there was not difference in the extraction efficiency between the times and times; there was difference in the extraction efficiency between 2, times and times extraction Furthermore, from the ANOVA result in Table 6, it was also shown that the extraction times did not significantly affect all the AV, PV, IV and SV of tea seed oil Therefore, for lower extraction cost, times extraction was selected to extract tea seed oil by solvent method 3.7 Results of the composition of fatty acid Analyses of fatty acid composition of extracted oil samples were at particle size 0.5 mm, material-solvent ratio 1/10, temperature 40 oC, time hours, speed of solvent movement 200 r/m and times extraction, whose the results are shown in the Table and a chromatogram of fatty acids in TSO sample is shown in Fig.1 Sengupta determined the composition of TAG in Indian tea seed oil and found that oleic (C18:1), linoleic (C18:2), palmitic (C16:0), and stearic (C18:0) acids were the major FA [27] The ratio of saturated fatty acids to the unsaturated fatty acid content was 1:3 (24.8 % : 75.2 %) Thus, the content of UFA is high in total content, the UFA content indicated that C18:1 and C18:2 acids are the major UFAS in all tea seed oil obtained by the extraction method Tea seed oil has a high content of unsaturated fatty acids, especially essential linoleic acid (22.68), which works to reduce blood cholesterol levels It also has low linolenic acid (C18:3 content (0.72 %), an important factor in rancidity and loss of flavor of oil during storage [28] Moreover, the oleic acid seed oil is the highest of all fatty acids, accounting for 50.8 % Tea seed oil is an oil with a characteristic acid component of oleic acid and linoleic acid, so it is considered a high quality oil 83 Phan Thi Phuong Thao, Tran Thi Thu Hang, Hoang Dinh Hoa, Vu Hong Son Table Composition fatty acid of tea seed oil Fatty acid C12:0 SFA MUFA PUFA Content (%) 0.01 C14:0 C16:0 C17:0 C18:0 C20:0 C24:0 Total C16:1 C18:1 C20:1 Total C18:2 C18:3 Total 0.12 17.2 0.16 6.95 0.21 0.15 24.8 0.21 50.8 0.79 51.8 22.68 0.72 23.4 Figure A representative GC chromatogram of the fatty acids in crude TSO CONCLUSIONS In the current research, single factor experiment approach was employed to determine the optimal cost-effective condition of the extraction process of tea seed oil Extraction parameters were found to have varying effects on the extraction efficiency, AV, PV, IV and SV of tea seed oil in the operating condition ranges selected in the experiment The extraction efficiency was significantly affected by parameters as particle size, material to solvent ratio, extraction temperature, extraction time and speed of solvent movement while it was not affected by 84 Effects of process parameters on the extraction efficiency and physicochemical characteristics… extraction cycle In addition, the particle size and extraction time had the most significant effect on the AV, IV and AV, respectively The extraction temperature and the speed of solvent movement had pronounced effects on all the AV, PV, IV and SV of tea seed oil However, the material/solvent ratio and extraction times did not appreciably affect on chemical characteristics of tea seed oil Furthermore, higher quality and performance characteristics were achieved in the range of temperature, size, material/solvent ratio, time, speed of solvent movement and number of extraction times: 35 to 45 oC, 0.5 mm, 1/8 to 1/12, to hours, 200 to 250 r/m, times extraction This study underpins an in-depth investigation of the optimization of extraction parameters of tea seed oil by surface reaction method, in other words, to 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Cultivars, Food and Nutrition Sciences (2016) 1-7 86 ... solvent for tea seed oil extraction 3.6 Effect of extraction times on the efficiency and physicochemical characteristics of tea seed oil Table Effect of extraction times on the efficiency and physicochemical. .. the contact between the solvent molecules and tea seed particles during the extraction process [1] When the 78 Effects of process parameters on the extraction efficiency and physicochemical characteristics ... extraction of tea seed oil 3.3 Effect of temperature on extraction efficiency and physicochemical characteristics of tea seed oil Table indicates that the extraction efficiency was directly proportional