Enzymatic interesterification of olive oil with fully hydrogenated palm oil: Characterization of fats

Seven different reaction products were prepared via enzymatic interesterification of extra‐virgin olive oil (EVOO) and fully hydrogenated palm oil (FHPO), by varying the initial weight ratio of EVOO to FHPO from 80 : 20 to 20 : 80. The chemical, physical and functional properties of both the semi‐solid reaction products and the corresponding physical blends of the precursor starting materials were characterized. Fats prepared using large proportions of FHPO contained high levels of TAG species containing only saturated fatty acid residues. By contrast, high levels of TAG species containing both saturated and unsaturated fatty acid residues were found in fat products obtained with the lowest proportions of FHPO. Independently of the initial weight ratio of EVOO to FHPO, the interesterified products were characterized by a higher molar ratio of unsaturated to saturated fatty acid residues at the sn‐2 position, were softer over a wide temperature range, exhibited lower oxidative stabilities and were completely melted at lower temperatures than the corresponding physical blends. Potential applications of the reaction products range from margarines (highest weight ratios of EVOO to FHPO) to frying fats (lowest weight ratios of EVOO to FHPO).     

Interesterification of sesame oil and a fully hydrogenated fat using an immobilized lipase catalyst in both batch and continuous‐flow processes

Lipase‐mediated interesterification of sesame oil and a fully hydrogenated soybean oil was studied at 70 °C in both a batch reactor (BR) and a continuous‐flow packed‐bed reactor (PBR) using four different initial weight ratios of substrates (90 : 10, 80 : 20, 70 : 30 and 60 : 40) with Lipozyme TL IM (Thermomyces lanuginosa) as the biocatalyst. Reaction rates were determined by following the dependence of the profile of the product triacylglycerols (TAG) on the reaction time (BR) or the space time (PBR) via RP‐HPLC‐ELSD. Product TAG identities were confirmed by HPLC‐APCI‐MS. Primary differences between the performances of the two reactors were the maximum level of net hydrolysis (ca. 3 and 10 wt‐% lower acylglycerols at equilibrium for the PBR and BR, respectively), the time or space time required to approach quasi‐equilibrium conditions, and less migration of acyl groups in the PBR trials. For the BR trials, quasi‐equilibrium conditions were approached in 4–6 h, while for the PBR trials short space times (15 min to 2 h) were sufficient to produce effluent compositions similar to equilibrium BR compositions. The predominant TAG families formed by interesterification were LLS, PSO, PSL, SSL, and SSO (L = linoleic; S = stearic; P = palmitic; O = oleic). Oxidative stabilities, melting profiles and solid fat contents were determined for selected reaction products.     

Production of structured lipids in a packed-bed reactor with <Emphasis Type="Italic">thermomyces lanuginosa</Emphasis> lipase

Lipase-catalyzed interesterification between fish oil and medium-chain TAG has been investigated in a packedbed reactor with a commercially immobilized enzyme. The enzyme, a Thermomyces lanuginosa lipase immobilized on silica by granulation (lipozyme TL IM; Novozymes A/S, Bagsvaerd, Denmark), has recently been developed for fat modification. This study focuses on the new characteristics of the lipase in a packed-bed reactor when applied to interesterification of TAG. The degree of reaction was strongly related to the flow rate (residence time) and temperature, whereas formation of hydrolysis by-products (DAG and FFA) were only slightly affected by reaction conditions. The degree of reaction reached equilibrium at 30–40 min residence time, and the most suitable temperature was 60°C or higher with respect to the maximal degree of reaction. The lipase was stable in a 2-wk continuous operation without adjustment of water content or activity of the column and the substrate mixture.