Prof. Dr. María Luján Ferreira is a researcher in CONICET (Argentina) since 1997 and a Professor in the Universidad Nacional del Sur, Argentina, since 1999. She has near 130 publications in peer reviewed journals, 3 National Prizes in Science (Bernardo Houssay 2004, Ranweel Caputto 2003 and First Mention in Lóreal -UNESCO in collaboration with CONICET Prize for Women in Science 2014). She works in nano and biotechnology, focused on lipases and oxidoreductases. Her research interests are focused in the search for new products (including structured triglycerides) and environmental remediation of dyes using advanced oxidation systems based on magnetic oxides as mimetics of oxidoreductases.

Prof. Dr. Gabriela Tonetto is a professor in the Chemical Engineering Department at the Universidad Nacional del Sur, Argentina, and Researcher in CONICET (Argentina) since 2005. She has near 50 publications in peer reviewed journals. Her research interests include heterogeneous catalysis and biocatalysis applied to oleochemistry.

1. Introduction: What¿s the importance of structured triglycerides (ST) and diglycerides (SD)?

1.1. Health aspects

1.2. Economic aspects

1.3. Synthesis aspects

1.4. Other considerations

2. Literature Review: What has been explored about enzymatic synthesis of ST and SD?

2.1. Enzymatic Synthesis of SD in one step

2.2. Enzymatic Synthesis of ST in one step

2.3. Enzymatic Synthesis of SD in two steps

2,5. Chemo-enzymatic synthesis of SD in two steps

2.6. Chemo-enzymatic synthesis of ST in two steps

2.7. Other enzymatic synthesis

3. Drawbacks: What problems arise when enzymatic synthesis of ST is performed?

3.1. Production in ST and SD in Batch Reactors

3.2. Production in ST and SD in Continuous Reactions

3.3. The use of adsorbents in ST and SD synthesis

3.4. Acyl migration in SD synthesis

3.5. Acyl migration in ST synthesis

3.6. Other problems

4. Potential Solutions: What can be done about the drawbacks in ST enzymatic synthesis?

4.1. The use of glycerol as substrate

4.2. The use of low-cost fatty acids or fatty acids mixtures as substrates

4.3. Sources of specific fatty acids

4.4. Other solutions

5. Industry perspective: What has to be taken into account when scaling-up from the lab to the industry?

5.1. Enzyme stability and reuse

5.2. Configurations that minimize acyl migrations. Are they feasible?

5.3. Operative and initial investment costs

6. Examples of successful industrial synthesis or potential industrial scaling of SD and ST

6.1. Maternal milk substitutes and other nutritional SD and ST

6.2. Other SD

6.3. Other ST

7. Conclusion: What does the future look like?

This brief presents the state of the art on enzymatic synthesis of structured triglycerides and diglycerides, focusing on glycerol as the substrate and covering interesterification of vegetable oils in one and two steps. It critically reviews the available literature on enzymatic and chemo-enzymatic synthesis of di- and triglycerides in one or more steps. The effects of the structure, length and unsaturation of the fatty acids are carefully considered, as well as the inhibitory potential of highly unsaturated complex fatty acid structures.

The brief also addresses acyl migration and the use of adsorbents, taking into account the most recent literature and presenting the problem in an industrial context. It discusses experimental and analytical problems concerning, e.g. the lab scale and the scaling up to bench and pilot plants. Several examples are presented, and their successes and failures are assessed. Biocatalysts based on lipases are analyzed with regard to problems of immobilization, stability on storage time and activity after multiple uses. The need for specific Sn-2 lipases is presented and strategies for optimizing Sn-2 esterification are discussed. Lastly, practical aspects are examined, e.g. lipase "leaching" with loss of activity, taking into account the latest findings on continuous and batch reactor configurations and presenting the advantages and disadvantages of each.