Effects of reaction parameters on the incorporation of caprylic acid into soybean oil for production of structured lipids


JOURNAL OF FOOD LIPIDS, vol.13, no.3, pp.306-317, 2006 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 13 Issue: 3
  • Publication Date: 2006
  • Doi Number: 10.1111/j.1745-4522.2006.00054.x
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.306-317
  • Hacettepe University Affiliated: Yes


Structured lipids (SLs) were synthesized by transesterification of soybean oil (SBO) and caprylic acid (CA) with sn-1,3-specific lipase (TL IM, Thermomyces lanuginosa) in a batch stirred-tank reactor without the use of solvent. Effects of variation in substrate mole ratio, temperature, enzyme load, reaction time and mixing speeds were investigated. To compare the effects of different parameters on the reaction, the default conditions were chosen as: temperature of 40C, stirring at 300 rpm, no extra water addition, enzyme dosage of 10 wt %, reaction time of 6 h and substrate mole ratio of 1:1 (SBO to CA). Products were analyzed by gas-liquid chromatography. An increase in substrate mole ratio decreased incorporation of CA into SBO. While the highest CA incorporation (7.84%) occurred at a mole ratio of 1:0.7 (SBO: CA) at default reaction conditions, 1:4 mole ratio gave the lowest value (0.52%). Optimum reaction temperature was 45C. As expected, the higher load of TL IM lipase in the reaction led to a higher incorporation of CA. At an enzyme dosage of 20 wt % in 6 h, the incorporation was 13.01%. A high incorporation of CA (7.19%) was obtained at 300 rpm, while 100 rpm gave the lowest incorporation (5.30%). A sharp increase was obtained for incorporation of CA into SBO during 18-h reaction. After this point of the reaction, incorporation was very slow. To elevate the extent of acidolysis, reactions were repeated thrice with CA. Repeated reactions caused an increase in CA content of triacylglycerols (TAGs). After the third reaction, the CA content of TAGs reached to 35.38%. The incorporation of CA was slightly reduced from the first use (18.43%) to the fifth use of enzyme (8.19%).