Quality markers, measuring food quality

Baker putting a tablet of buns or bread into an oven
Baker putting a tablet of buns or bread into an oven

No longer an abstract concept but a measurable method that uses mathematical models to optimize processes. Also the identification of quality markers and the analysis of their dynamics can provide objective answers for changes in quality

Food quality: a term that is widely used and often abused by companies when describing their products and processes. We asked Davide Papasidero from the “Giulio Natta” Department of Chemistry, Materials and Chemical Engineering at the Politecnico Univerisity in Milan to explain the concept of food quality and markers that can be monitored and optimized using chemical kinetics and computational fluid dynamics.

Davide Papasidero from the “Giulio Natta” Department of Chemistry, Materials and Chemical Engineering at the Politecnico Univerisity in Milan

What is meant by food quality?
Paraphrasing a brilliant article written by M. Ferree in February 1973, the concept of food quality depends on who is defining it, for example an agency, an institution, or a food buyer. When asking some colleagues with different educational backgrounds to define “food quality”, I received a wide array of answers. The concept of “good”, as in tasting good, was the most common. “Healthy” and “energizing” were associated with the effect that food has on the body. “Prepared well” was related to the cooking aspect of food, just as “from natural ingredients” was related to the raw materials used. “A supply chain that is traceable” was the answer from one concerned with ability to track food from its origin in the field all the way to the product that ends up on the table. For a more objective definition, you can refer to academic studies. Food Quality edited by Kapiris (2012) includes all of these ideas. “Food quality is represented by the characteristics that are acceptable to the consumer. This includes external factors like aspect (size, shape, brightness, color), texture and taste. Other factors are legal quality standards and internal factors (chemical, physical, microbiological). Many consumers base their ideas on production and processing standards, referring in particular to ingredients as they apply to nutritional, dietetic or medical requirements (for allergies or diabetes as an example). Food quality also involves traceability and labelling and is directly related to health and hygiene standards.” In this sense, techniques and tools for assessment and analysis come to the aid of food engineers and technologists so that food quality can be measured objectively. These tools are based on the identification, description and measurement of key parameters associated with quality and are called “markers”.

What are some food quality markers?
Some markers are associated with the five senses. Color is one of the main quality indicators from the consumer’s visual point of view. A bakery item that is not browned enough, for example, has little appeal, just like pasta that is too white or too dark. At the same time, a product showing signs of mold is immediately to be scrapped, unless mold is one of the product’s features as in the case of some dairy products. The smell of the food is equally important and depends on the presence of key molecules that define the olfactory profile as either appealing or repelling. The perception of the quality of a smell is immediate and is often permanently associated in a person’s memory. Sometimes it is complex to measure and identify key olfactory elements due to the indirect effect of their levels of concentration on the organism (this depends on the specific threshold of perception for each element). Smell and taste are related to the chemical aspects of the food, while texture is associated with the microstructure of the item. In addition to these, there are the microbiological aspects like shelf-life, and also pre- and pro-biotic additives. And then there is the nutritional value. The final item on this rather complex list is the recent branch called “Foodomics” that joins together metabolomics, genomics, transcriptomics, and proteomics and is aimed at correlating metabolites, genomes, mRNA, and proteins to their functions as related to human nutrition.

How are markers monitored and optimized using chemical kinetics and computational fluid dynamics?
Before going into detail on these items, the concept of mathematical modelling needs to be introduced. A mathematical model involves the use of formulas to represent a system that is as close as possible to reality. In this regard, it is important to identify the objectives, the means and the time available to go and study the system. A classic example of a model is the ideal gas law that approximates the behavior of a gas under variable conditions. Chemical kinetics is a branch of chemistry and chemical engineering that studies the dynamic evolution of chemical systems based on the different operating conditions, using models (kinetic systems, reaction models, etc.) to approximate real systems. When describing the assorted situations, it is often coupled with the analysis of transport phenomena, which includes among other things, heat conduction, mass transfer, fluid dynamics and the mathematical formulas required for these fields of applications. In many food processes, we find the compresence of these phenomena. The analysis of food processes must describe these conditions in relation to the dynamic evolution (time) of some markers, linked to some of the aspects cited above. More precise modelling has been made possible by the increased computational capacity that is now available to research (in terms of calculation speed, number of processes, memory, etc.) as well as the advancement of testing techniques.