What’s the Most Dangerous Color?

I have always believed in taking risks – in life and in science. In my experience, most risks bring proportionate rewards. Importantly, you can take risks not only in your actions, but also in the way you think. Do you think conventionally and stick to your comfort zone? Or do you think daringly and take a gamble? Most huge (and small) advances in science have been based on risky hypotheses (often considered illogical or bizarre at the time).

In our laboratory, we move from big to small and vice versa; between chemical engineering and analytical chemistry, between sample preparation techniques and process design, between micro- and pilot scale. What our projects have in common is the desire to develop systems, processes and methodologies that follow ‘green chemistry’ principles. Ideas about sustainability, environmental impact, green solvents, selectivity, efficiency, and so on, can be applied in all processes and all scales. So why not translate a sample preparation methodology to a pilot scale process? Why not develop a process at large scale and then use that knowledge to improve sample preparation techniques?

In the Foodomics Laboratory (Institute of Food Science Research, CIAL, CSIC-UAM), we defined foodomics several years ago as “a new discipline that studies the food and nutrition domains through the application of advanced omics technologies in order to improve consumer’s well-being, health, and confidence” (1). By definition, foodomics is a ‘green’ discipline because it gives new answers to important societal challenges; for example, sustainability, food safety and quality, the rational design and development of new foods able to improve our health or prevent diseases. Attaining these goals helps to provide safer foods with lower contamination and chemical risk. But we aim to go further in making foodomics a green discipline (2).

Two obvious ways to make foodomics greener are the use of green solvents, and switching to integrated processes with less waste and energy consumption. These approaches can be applied to both the development of extraction processes for functional food ingredients and the design of greener analytical methods to measure food quality, safety and traceability. The use of miniaturized sample preparation techniques or greener solvents, and the development of greener separation techniques is a must. By developing green foodomics we can also influence other -omics technologies (mainly proteomics and metabolomics) to cut preparation steps and consumption of solvents, while improving data reliability.

Let’s consider some examples. First, from the ‘big’ point of view (chemical engineering, pilot scale), an important aspect is how functional ingredients are obtained. Traditional extraction techniques (soxhlet, sonication, solid-liquid extraction, liquid-liquid extraction) require long extraction times and large samples, provide low selectivity and, generally, low extraction yields, and need high volumes of organic solvents, resulting in the generation of large quantities of solvent waste. There is enormous interest in more environmentally friendly techniques that can overcome these drawbacks. Among them, ultrasound-assisted extraction and microwave-assisted extraction are versatile approaches that make it possible to use several solvents of different polarities, allow fast extractions and decrease the amount of solvents used. In addition, the development of advanced pressurized extraction techniques (such as supercritical fluid extraction, pressurized liquid extraction or pressurized hot water extraction – also called subcritical water extraction) perfectly comply with the principles of green chemistry and green engineering, and could represent a key turning point in sustainable development.

From the ‘small’ point of view, we are developing methods in green analytical chemistry. Analytical methods can be considered processes in which preliminary information and knowledge, solvents, reagents, samples, energy and instrument measurements are used as inputs to solve a specific problem. The outputs of those processes are the qualitative and/or quantitative composition of the analytes. However, analytical methodologies can also have side effects (for example, energy consumption, toxic waste products). Key approaches to mitigate the adverse environmental impact of analytical methodologies are: i) reducing the amount and toxicity of solvents in the sample pre-treatment step; ii) reducing the amount and toxicity of solvents in the measurement step, especially by miniaturization; and iii) developing alternative direct analytical methodologies that do not require solvents or reagents.

Now, what if we – as analytical chemists and/or engineers – focus on measuring the ‘greenness’ of a process or analytical methodology and on gathering the necessary knowledge so that we are able to better translate the concepts bi-directionally? Then it’s just a case of leaving the rest to our imagination!