Performance of Green Solvents in the Extraction of Sunflower Oil from Enzyme‐Treated Collets

Abstract

The main goal of this work is to evaluate the extraction of sunflower oil from enzyme‐treated collets using ethanol and isopropanol (IPA) as solvents. The sunflower collets are pretreated with the multienzyme complex Viscozyme L prior to solvent extraction by the Soxhlet method. The influence of the moisture content of the collets, pretreatment, processing time, and solvent type on the amount of total extracted material and the oil extraction efficiency is studied. Some quality parameters such as phospholipid content of the oil and chlorogenic acid content of the residual meal are also analyzed. At low moisture content (7%) the solvents exhibit similar oil extraction ability (98–99%), but with increasing moisture the extraction efficiency of ethanol decreases to about 85%, while no significant differences are observed for IPA. The enzymatic treatment increases the extraction efficiency for all times, especially for ethanol. It is observed that IPA is more efficient in the extraction compared to ethanol, and the amount of nonlipid material is reduced by ≈70%. In addition, the oil extracted with IPA have lower phospholipid content and the residual meal presents a higher chlorogenic acid content. Practical Applications:This work would contribute toward the use of green solvents in the extraction of sunflower oil from collets. Ethanol and isopropanol, used as solvents, present attractive advantages, including low toxicity, good operational security, as well as being obtained from a renewable source. The obtained data provide up‐to‐date information on the use of these alcohols in the extraction of sunflower oil from collets and the influence of operating conditions, such as moisture content, enzymatic pretreatment of the collets, and the extraction time. Information about oil and meal quality is also reported.

Impact of Hydro-Alcoholic Solvents on the Oil and Phenolics Extraction from Walnut (Juglans regia L.) Press-Cake and the Self-Emulsification of Extracts

“…For oil extraction, there is evidence in the literature that short-chain alcohols such as ethanol and isopropanol could replace hexane in vegetable oils extraction [ 20 , 23 , 25 , 26 , 27 , 51 , 52 ], but the presence of water is detrimental to the oil solubility or recovery [ 30 , 53 , 54 , 55 , 56 ]. Our results are consistent with the trends reported in the literature, since a higher hydration level of the extracting solvent decreased the oil extraction yield.…”

“…In comparison, the yield of polar compounds extraction, evaluated by the difference between the global and the oil extraction yields, ranged between 7 ± 3% and 9 ± 3% but the difference was not statistically significant. By increasing the hydration level of solvents, the solvent increases its ability to extract non-oil compounds [ 21 ] such as carbohydrates [ 26 ] and proteins [ 27 , 54 ]. In the cited references, the trends were evaluated for ethanol- or isopropanol-based mixtures with a water content varying from 0 to 12wt%.…”

“…Due to its polarity, ethanol is a weaker solvent than hexane for triglycerides especially in the presence of water, but it can extract a greater variety of polar substances such as phospholipids, soluble sugars and phenolic compounds [ 22 , 23 ]. Isopropyl alcohol has also a high miscibility with oils and is more tolerant to water than ethanol in that the decrease of oil extraction yield with the hydration level of the solvent [ 24 , 25 , 26 ] or with the matrix moisture [ 27 ] is less pronounced. Compared to hexane, its use resulted in higher extraction rates and oil recoveries [ 27 , 28 ], though the reverse was also observed [ 29 ].…”

“…Isopropyl alcohol has also a high miscibility with oils and is more tolerant to water than ethanol in that the decrease of oil extraction yield with the hydration level of the solvent [ 24 , 25 , 26 ] or with the matrix moisture [ 27 ] is less pronounced. Compared to hexane, its use resulted in higher extraction rates and oil recoveries [ 27 , 28 ], though the reverse was also observed [ 29 ]. More polar molecules may be extracted along with the oil such as water, carbohydrates and proteins [ 26 , 30 ].…”

Bioactivity Potential of Industrial Sunflower Meal Ethanol-Wash Solute Obtained as Waste from Protein Isolation Process

“…It is most probably due to the higher polarity of the ethanol compared to hexane, leading to higher extraction efficiency [46]. Baümler et al [33] and Rodriguez et al [47] demonstrated the feasibility of using ethanol as an alternative solvent to hexane in the oil extraction from sunflower collets, regardless of the low selectivity of the reagent and the relatively high amount of non-lipid compounds in the extracted material. Recently, there has been an escalating interest in ethanol as a "green" extracting agent of vegetable oil due to its low toxicity and handling risks [33,46,47].…”