Production of Structured Triacylglycerol via Enzymatic Interesterification of Medium‐Chain Triacylglycerol and Soybean Oil Using a Pilot‐Scale Solvent‐Free Packed Bed Reactor

Abstract

Oils rich in medium‐ and long‐chain triacylglycerols (MLCT) serve as functional oils to help reduce body fat accumulation and weight gain. However, most of the MLCT‐rich products on the market are physical blends of medium‐ and long‐chain triacylglycerols (MCT and LCT, respectively) that are not structured triacylglycerols (TAG). In this study, an efficient pilot‐scale packed bed reactor (PBR) of immobilized lipase from Thermomyces lanuginosus (Lipozyme® TL IM, Novozymes, Bagsvaerd, Denmark) was employed for producing structured MLCT via 1,3‐specific interesterification of TAG enriched in caprylic and capric acyl groups and soybean oil (SBO). The PBR was operated under continuous recirculation mode in the absence of solvent. Optimal reaction conditions were determined to be: caprylic/capric TAG: SBO ratio (45:55 w/w), reaction temperature (75 °C) and residence time (16.0 min) on MLCT production were studied. When employing a pilot‐scale PBR (100 kg day−1) under optimal conditions, a product containing 76.61 wt% MLCT was produced. Lipozyme TL IM was reused for 25 successive batch reactions (125 kg substrates) with no significant reduction in catalytic efficiency. The light yellow MLCT‐enriched product had a high level of saturated fatty acids (SFA, 82.74 wt%) in its sn‐2 position as a result of the enzyme's 1,3‐positional specificity. One‐stage molecular distillation and methanol extraction were used to remove the free fatty acids, mono‐, and diacylglycerols generated from hydrolysis. With distillation temperature of 150 °C and oil‐to‐methanol ratio of 1:3 v/v, MLCT content was further increased to 80.07 wt%. The enzymatic PBR was therefore effective in producing structured MLCT at a pilot‐scale under solvent‐free conditions.

Applied Studies on Application of Capric/Caprylic MCT Oils in Food Industries

“…Pilot-Scale Solvent-Free Packed Bed Reactor (PBR) was used for production of structured triacylglycerol via Enzymatic Interesterification of Medium-Chain Triacylglycerol and Soybean Oil using Lipozyme TL IM 1,3 selective enzyme [14].…”

“…TAG -Chromatograms diagrams are shown in Diagram 1. Structured lipids containing combinations of LCFA at sn-2 and MCFAs at the sn-1,3 position, so-called medium-long-medium (MLM) TAG, will provide lipids with high coefficient absorption [14,15]. It has been reported that MLM structured lipids have a low caloric value, and can be used to control obesity, fat malabsorption, and other metabolic disorders.…”

“…However, the melting curves for 50:50 palm: MCT blends gave non-sharp melting points for both inter-esterified and non-inter-esterified substrates blends. According to Zhen Zhang et al (2020) [14], the increase in the onset crystallization temperature of inter-esterified MCT/LCT substrate (from −30.06 •C to −27.67 •C) and widening of the melting range after enzymatic interesterification likely reflect the change of acylglycerol composition and profile of TAG species According to Wang et al, 2016 [31], TAG hydrolysis occurred as a side-reaction during enzymatic transesterification observed by the formation of MAG (2.93%) and DAG (8.61%).…”

Synthesis of Dietetic Structured Lipids from Spent Coffee Grounds Crude Oil Catalyzed by Commercial Immobilized Lipases and Immobilized Rhizopus oryzae Lipase on Biochar and Hybrid Support

“…Zhang et al [29] produced structured low-calorie TAG by interesterification of soybean oil with TAG rich in caprylic and capric acyl groups, in solvent-free media, catalyzed by Lipozyme TL IM. This biocatalyst was used in a pilot-scale packed-bed batch reactor (to avoid particle disintegration) and reused for 25 successive batch reactions (16 min/batch).…”

“…Low-calorie SL can be produced enzymatically either (i) by acidolysis of a TAG or oil, containing long-chain fatty acids, with a medium-chain fatty acid [26], or (ii) by interesterification of a TAG or oil with methyl or ethyl esters (fatty acid methyl esters, FAME, or fatty acid ethyl esters, FAEE) of medium-chain fatty acids [27,28] or medium-chain TAG [29]. Reactions catalyzed by enzymes are carried out under mild temperatures, reducing energy consumption, leading to a decrease in the loss of temperature-sensitive molecules (substrates and/or products), and resulting in more environment-friendly and safer processes.…”