Interactive roles of co-solvents and lemon-oil composition in the fabrication of dilutable clear emulsions.

Clear emulsions are used as flavor carriers by the beverage industry because of their favorable optical properties. A transparent microemulsion with small droplets requires a high concentration of surfactants, and is often non-dilutable, posing a significant challenge to their application in the food industry. The formation of dilutable microemulsions by modulating the compatibility of oil composition and co-solvents was studied. While single-fold lemon oil exhibited poor loading capacity overall, no precipitation occurred due to the stronger interaction between monoterpenes and sucrose monopalmitate (SMP). Conversely, emulsification of five-fold lemon oil with 20 % ethanol demonstrated a higher loading capacity and a stronger dilution stability than other lemon oils. This is likely due to the balanced composition of surface-active monoterpenes and other components in five-fold lemon oil which facilitated the effective use of micellar space and aided in the retention of both surfactants and co-solvents post-dilution. The emulsification of higher-folded lemon oil, however, was favored by the use of propylene glycol as a surfactant exhibiting stronger dilution stability than ethanol, though it required twice as much co-solvent. The high concentration of surface-active monoterpene in the lower-folded lemon oils competes with propylene glycol for interfacial incorporation. This study demonstrated that co-solvents and oil composition play interactive roles in producing dilutable optically clear emulsions, and it provides a blueprint for the food industry to design colloidal systems using a minimum of surfactants.

Preparation of highly purified pinolenic acid from pine nut oil using a combination of enzymatic esterification and urea complexation.

Pinolenic acid (PLA) is a polyunsaturated fatty acid of plant origin. PLA has been successfully enriched according to a two-step process involving lipase-catalysed esterification and urea complexation. For the first step, the fatty acids present in pine nut oil were selectively esterified with lauryl alcohol using Candida rugosa lipase. Under the optimum conditions of 0.1% enzyme loading, 10% additional water, and 15 °C, PLA was enriched up to 43 mol% from an initial value of 13 mol% in the pine nut oil. For the second step, the PLA-enriched fraction from the first step was subjected to a urea complexation process. In this way, PLA enrichments with purities greater than 95 mol% were obtained at urea to fatty acid ratios greater than 3:1 (wt/wt), and 100% pure PLA was produced at a urea to fatty acid ratio of 5:1 with an 8.7 mol% yield.

Immobilized phospholipase A1-catalyzed modification of phosphatidylcholine with n-3 polyunsaturated fatty acid.

n-3 Polyunsaturated fatty acids (n-3 PUFA)-enriched phosphatidylcholine (PC) was successfully produced with fatty acid from fish oil and PC from soybean by immobilized phospholipase A1-catalyzed acidolysis. Detailed studies of immobilization were carried out, and Lewatit VP OC 1600 was selected as a carrier for preparation of immobilized phospholipase A1, which was used for modification of PC by acidolysis. For acidolysis of PC with n-3 PUFA, the effects of several parameters, namely, water content, temperature, and enzyme loading on the reaction time course were investigated to determine optimum conditions. The optimum water content, temperature, and enzyme loading were 1.0%, 55 °C, and 20%, respectively. The highest incorporation (57.4 mol%) of n-3 PUFA into PC was obtained at 24h and the yield of PC was 16.7 mol%. The yield of PC increased significantly by application of vacuum, even though a slight decrease of n-3 PUFA incorporation was observed.

Synthesis of phytosteryl ester containing pinolenic acid in a solvent-free system using immobilized Candida rugosa lipase.

Phytosteryl ester synthesized with pinolenic acid (PLA) from pine nut oil is expected to have features of both phytosterol and PLA. In this study, lipase from Candida rugosa (CRL) was immobilized and then used to optimize conditions for synthesis of phytosteryl ester containing PLA. Lewatit VP OC 1600, a macroporous hydrophobic resin, was selected as the best carrier, and the optimum condition for the immobilization of CRL was established. With immobilized CRL prepared, synthesis of phytosteryl ester with fatty acid from pine nut oil was carried out. Parameters investigated were temperature, molar ratio (phytosterol to fatty acid), enzyme loading, and vacuum. Optimum conditions for synthesis of phytosteryl ester were a temperature of 60 °C, molar ratio of 1:4, enzyme loading of 10% (based on the total weight of the substrate), and pressure of 80 kPa. The maximum conversion of phytosteryl ester was ca. 93 mol % at the optimum condition.