Synthesis Of Resveratrol Fatty Acid Esters And Development Of Oleogel Products

Resveratrol is a non-flavonoid polyphenol compound,and exhibits anti-inflammatory,anti-oxidant,and anti-tumor effects.It has a high melting point,is insoluble in water,and has poor fat solubility,which limits its application in the food and medical fields.The esterification modification can reduce the melting point,greatly improve the fat solubility and bioavailability of resveratrol,and make it better than reveratrol in terms of health function.Oleogel is a new type of plastic fat,which can replace the traditional solid fat,and has great application prospect and potential in food,medicine and cosmetics.Natural beeswax is a complex organic compound secreted by worker beeswax glands and is widely used in the food industry,but the oleogel prepared with beeswax alone still has excessive hardness and viscosity,difficult to spread,and poor thixotropy even at the critical gel concentration.Problems,industrial application faces certain challenges,and finding a suitable beeswax compounding agent is the key to obtaining a specific functionalized oleogel.Therefore,in this paper,9c,11t-conjugated linoleic acid was esterified to modify resveratrol,and its separation,purification and structural characterization were carried out to reveal the mechanism of esterification modification,and then compounded with beeswax to prepare resveratrol conjugated linoleate oleogel,Its basic physical and chemical properties,crystal structure and fatty acid composition were analyzed.The main contents and conclusions were as follows:（1）The optimal preparation process of resveratrol-conjugated linoleate was determined by single factor experiment: the molar ratio of alkyd was 1: 3,the molar ratio of acid CDI was1: 1,and the esterification time was 2 h.The carboxylic acid activation time was 30 min,and the solvent addition amount was 20 m L.Under these conditions,the conversion rate of resveratrol was 96.8%.（2）The prepared resveratrol conjugated linoleate crude product was successively washed with water,saturated sodium chloride and anhydrous ethanol for several times,then a small amount of anhydrous sodium sulfate was added and stirred overnight.And then resveratrol conjugated linoleate pure product was obtainedafter suction filtration,rotary evaporation and freeze-drying.The structure of the purified resveratrol conjugated linoleate was characterized and its basic physical and chemical indicators were also determined.FTIR spectra showed that resveratrol was successfully converted into resveratrol conjugated linoleate.TLC and NMR spectra showed that the product was resveratrol triesters.UV spectra showed that the maximum absorption wavelength of resveratrol conjugated linoleate was almost the same as that of resveratrol（306 nm）.The appearance of resveratrol conjugated linoleate was light yellow viscous oil,and its fat solubility was almost insoluble to completely miscible.The acid value was 1.8 mg/g,and the peroxide value was less than 5 meq/kg.TG thermogram showed that the thermal stability increased after esterification modification.（3）The mechanism of 9c,11t-conjugated linoleic acid esterification modified resveratrol was revealed.It was confirmed by quantum chemical calculation that the esterification first occurred at the C4’ position,followed by the C5 and C3 positions.After the formation of the monoester product,the energy barrier to form diesters and triesters gradually decreased.（4）Using peanut oil as base oil,resveratrol conjugated linoleate oleogel was prepared by compounding resveratrol conjugated linoleate and beeswax.The effect of beeswax and resveratrol conjugated linoleate addition（BRE）,mass ratio of beeswax and resveratrol conjugated linoleate,heating temperature,heating time and cooling temperature on the oil retention of oleogel rich in resveratrol conjugated linoleate was discussed,and its basic physical and chemical properties,thermal properties,and composition were characterized.The results showed BRE was 12%,the mass ratio of beeswax to resveratrol conjugated linoleate was 7: 3,the heating temperature was 70℃,the heating time was 20 min,and the cooling temperature was 4℃.The oil retention of oleogel rich in resveratrol conjugated linoleate could reach up to 98.6%.Compared with beeswax oleogel,the viscosity was reduced by 30%,the brightness and the α-type crystals were reduced.It was found that oleogel rich in resveratrol conjugated linoleate had no trans fatty acid.