Enzymatic esterification of rice bran oil and phytosterol in supercritical CO ₂

Abstract

In this paper, the esterification of phytosterol and free fatty acids (FFA) in rice bran oil (RBO) was studied using Novozym 435 in supercritical CO2. It was found that with the increase in CO2 filling pressure, the esterification reaction rate also increased. When the pressure exceeded the critical point, CO2 fluid had a great effect on phytosterol conversion. Therefore, enzymatic esterification deacidification was studied when the CO2 filling pressure was 8.0 MPa, the results showed that when the lipase dosage was 3.0%, the phytosterol concentration was 18.0%, the molecular sieve addition was 10.0%, and the esterification temperature was 78°C, after 41 hr the FFA content of RBO decreased to 1.1%, the phytosterol conversion rate reached 93.2%, and the vitamin E (VE) retention in the product was 80.0%. Therefore, the esterification by Novozymes 435 in supercritical CO2 could have several applications in fats and oils industry. Practical applications Much research has been done on the interesterification of vegetable oil in order to produce edible fats and oils. The current study provides a reliable and simple method for the esterification of phytosterol and free fatty acids (FFA) in rice bran oil (RBO). The optimal operating conditions lead to high quality oil. The FFA content of RBO decreased to 1.1%, the phytosterol conversion rate reached 93.2%, and the VE content in the product was 80.0%. The esterification by Novozymes 435 in supercritical CO2 could be applied in fats and oils industry.

Lipases as Effective Green Biocatalysts for Phytosterol Esters’ Production: A Review

“…C. rugosa lipases are commercially available, usually as a mixture of isoenzymes, and are among of the most frequently used enzymes in biotransformations [138]. Lipase B from Candida antarctica (CALB), the most used commercial lipase, is also identified in Table 2 in a work performed by Yu et al [76] in 2019, with high conversion values (93.2%). Additionally, He et al [65] compared this enzyme with C. rugosa lipase for the transesterification of phytosterols with ethyl linolenate and obtained a conversion four times lower than for CALB.…”

“…There are still a few studies using supercritical fluids for the synthesis of phytosterol esters. YU et al [76] studied the esterification of phytosterol and free fatty acids using Novozyme 435 in supercritical CO 2 and found that with increasing CO 2 filling pressure, the esterification reaction rate also increased, obtaining an esterification yield of 93.2%.…”

“…Compared to organic solvents, supercritical fluid can be considered a solvent-free system and can be used in the food industry because of low toxicity. This strategy has been tested for phytosterol ester synthesis catalyzed by lipase with success [76]. Recently, a simple mathematical tool called Substrate-Enzyme Relation (SER) was developed by de Sousa et al [185] to conciliate the thermodynamics' and kinetics' aspects towards high conversions in enzymatic ester synthesis, indicating a range of reaction conditions to accomplish that.…”

Supercritical CO2‐assisted Ru‐Pd/USY synchronised isomerisation to produce rice bran oil rich in conjugated linoleic acid

“…This proved the existence of a synergistic effect between bimetallic catalysts (Mironenko et al, 2018). Yu et al (2019) performed an enzymatic esterification reaction in supercritical CO 2 , which shortened the esterification time and made the conversion rate of plant sterols reach 93.2%. Yu et al (2017) performed a hydrogenation reaction in supercritical CO 2 , and the reaction time was reduced by 4 h.…”

“…Yu et al . (2019) performed an enzymatic esterification reaction in supercritical CO 2 , which shortened the esterification time and made the conversion rate of plant sterols reach 93.2%. Yu et al .…”