Friday 14 June 2024
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Nancy Cordoba: “We aim to establish the specific aroma and non-volatile components involved in the perception of sweetness in coffee taste”

The researcher: "We have to continue working towards correlating sensory analysis with chemical data to identify the specific compounds responsible for key flavor attributes such as fruity notes, floral aromas, or sweet, acidic, bitter undertones. This knowledge empowers us to develop more accurate flavor profiles, improve quality control measures, and even breed coffee varieties with specific desired flavor characteristics."

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MILAN – When talking about coffee in a scientific way, it is necessary to lean on those doing research in the field: sensory analysis and how it can prove to be chemically determinative is one of the subjects studied by the Postdoctoral Researcher at The Ohio State University, Nancy Cordoba.

Cordoba, from Colombia, one of the countries of origin of the bean, was your passion then transformed into research around this raw material?

“Absolutely! My passion for coffee was indeed transformed into research around this remarkable raw material. Hailing from the department of Nariño in Colombia, a region renowned for its exceptional quality and strong coffee tradition, I had the privilege of being born and raised at the heart of coffee production. As an agro-industrial engineer, my journey in the coffee industry began with my first work experience, where I was fortunate to be involved in the implementation of the (back then) groundbreaking Starbuck’s C.A.F.E. practices.

Cordoba working in the lab (photo granted)

Soon I realized that the future of the coffee sector lies in pushing boundaries, challenging existing paradigms, and transforming them with scientific advancements tailored to the market’s needs. In coffee, the learning never ceases, but that’s part of the excitement!
There are always fresh concepts and ideas to explore, making it a dynamic field where we must constantly strive to go further, add more value, and bring greater prosperity to our regions.

As an engineer, I was privileged to have acquired early exposure to the scientific method and problem-solving approaches. These invaluable tools became the foundation for advancing knowledge in my specific area of expertise. When the insatiable curiosity to learn infects your soul, it becomes difficult to resist its call.”

Cordoba, how long has your research been going on, and how much longer should it take in perspective to get the first decisive results?

“The research project on exploring sweetness began with the idea’s inception in 2021. Since then, considerable effort has been invested in structuring a comprehensive proposal. However, the project was officially launched in the fall of 2022.

Considering the overall timeline, this project is expected to deliver the first decisive results by the end of this year. The project was designed for two years, meaning that by the end of the timeline, significant findings and conclusions should be available (sometime in late 2024).


It’s worth noting that research timelines can sometimes be subject to adjustments based on various factors, such as unforeseen challenges, resource availability, or changes in scope. However, as of now, the plan is to complete the project and provide initial conclusive outcomes within the projected two-year timeframe mentioned.”

What is the gap that exists between chemical and sensory science in coffee? And what techniques are you studying to bridge it?

Cordoba: “The gap that exists between chemical and sensory science in coffee arises from the need to understand how the chemical components of coffee translate into our perception of flavor and sensory experience. While advancements in instrumental techniques allow us to extensively analyze the chemical composition of coffee, its complexity is influenced by various factors such as genetics, environment, post-harvest handling, roasting, and beverage preparation.

Although chemical analysis provides valuable information about the compounds present in coffee and their impact on flavor, aroma, and sensory aspects, there is still a need to bridge the understanding of how these chemical components relate to our perception of taste and overall sensory experience. In my ongoing project, we are utilizing an innovative technique called flavoromics to enhance our understanding of coffee complexity.

This approach focuses on establishing a connection between the chemical composition of coffee and the sensory data associated with them. By investigating volatile and non-volatile compounds in coffee, we aim to identify potential chemical stimuli that influence human flavor perception, surpassing the known flavor-influencing compounds.

This methodology enables us to screen various compounds that may correlate with flavor and subsequently subject them to sensory analysis to validate their actual contribution to the overall flavor profile. It is a novel approach because the traditional methodologies mainly focus on already known molecules, and in some cases, their sensory real contribution is not tested or neglected.”

Why do most consumers (Italians then in particular) confuse acidity with bitterness in a coffee?

“The confusion between acidity and bitterness in coffee can be attributed to various factors. One possible reason is the lack of distinction or understanding of the terms “bitter” and “acid/sour.” Individual physiological differences, cultural influences, and sensory evaluation exposure also contribute to flavor perception variations. It’s important to note that these observations are based on general trends and cultural preferences, but individual preferences and experiences may differ.

For example, based on my experience, in Italian coffee culture there is a strong preference for dark roasts, which tend to have a more pronounced bitterness. This preference has been passed down through generations, leading to an association between bitterness and a desirable coffee flavor. As a result, the nuances of acidity, which can be perceived as a sour or tangy taste, may not be as appreciated or understood by the average Italian consumer.

Additionally, many Italian coffee drinkers are accustomed to traditional espresso, which may not always exhibit a well-balanced acidity. This limited exposure to coffee with a well-balanced acidity can contribute to the confusion between acidity and bitterness. Furthermore, language also plays a role in flavor perception, as linguistic limitations can lead to the generalization of taste and flavors. Specific molecules in coffee further influence the perception of bitterness and sourness.

Different chemical structures and properties of acids can elicit varying sensations, including bitter or even salty tastes. In summary, the confusion between acidity and bitterness in coffee could arise from a combination of factors, including the lack of distinction between the terms, individual physiological differences, cultural influences, exposure to certain coffee profiles, language limitations, and the influence of specific molecules on taste perception.”

What are the chemical compositions that contribute to emphasizing the sweet note in a coffee?

Cordoba: “Our understanding of the sweetness in coffee is still a puzzle we’re trying to solve. Regarding coffee brews, there is still limited information available to establish whether the sweetness perception in the coffee beverage is a response to direct stimulus in the gustatory system or whether it is driven by multimodal mechanisms, like those that occur by odor-induced changes affecting taste perception.

Which is why our project is focused on unraveling this mystery and gaining insights into the chemical composition that contributes to the sweet taste of coffee. Contrary to what you might expect, some few studies have shown that the amount of sugar alone in filtered coffee is not enough to make it taste sweet. This means that there are other chemical compounds or mechanisms at play.

One theory suggests that specific volatile compounds found in coffee, released as aromas during the coffee-making process, may be involved in our perception of sweetness. These compounds have familiar scents like strawberry, vanilla, caramel, and fruity notes, and they work together with the taste of coffee to create a sweeter experience.

It’s important to note that not all aromatic compounds have this effect. Although coffee contains thousands of different compounds, not all of them contribute to the perception of sweetness. While some chemical compounds in coffee have sweet aroma properties, we are still investigating how these compounds interact within the coffee itself. Our goal is to better understand the precise relationship between coffee’s chemical composition and our perception of sweetness.

To delve deeper into the sweetness of coffee, we are exploring two primary ideas. One suggests that the sweetness we taste is a direct result of the interaction between the chemical compounds dissolved in coffee and our taste buds in our mouth. The other idea proposes that our perception of sweetness is influenced by a combination of taste and
smell, where certain aromas can actually change how we perceive sweetness, creating a multi-sensory experience.

Although we don’t have all the answers yet, our ongoing research aims to shed light on the factors that contribute to the sweet taste in coffee. By gaining a deeper understanding of the chemical composition, we hope to enhance the appreciation and enjoyment of sweetness in every coffee cup we savor.

Can the same experiment be done for other components, such as umami or indeed, acidity?

“Certainly! The flavoromics approach, which involves studying the chemical composition of food and its relationship to sensory perception, can indeed be applied to explore other taste attributes, such as umami or acidity. In the case of coffee, acidity is a key component that contributes to its overall flavor profile.

The perceived acidity of coffee is influenced by various chemical compounds, particularly organic acids. However, not all organic acids contribute to the same acidity taste quality. By studying the specific chemical compounds responsible for acidity in coffee, researchers can better understand how these compounds interact and contribute to the perceived acidity and overall flavor experience.

The flavoromics approach is not limited to coffee alone but can also be applied to a wide range of foodstuffs. By analyzing the chemical composition of different foods and their relationship to sensory perception, researchers can unravel the complex interactions that shape our perception of taste and consumer preferences.”

Cordoba, you analyzed the beverage from a chemical-sensory point of view: what did you find out about the various aroma components?

“During our ongoing research project, we have been analyzing the beverage from a chemical-sensory perspective to understand the various aroma components and non- volatile compounds and their influence on sweetness perception. While we are still in the process of gathering and analyzing data, we have discovered some interesting clues.
Based on preliminary findings, it appears that a significant portion of sweetness perception in the beverage may indeed be influenced by aroma components. However, I would like to exercise caution and refrain from providing a definitive answer at this point.

As we continue our research and collect more data over the next months, we aim to establish a more comprehensive understanding of the specific aroma and non-volatile components involved in sweetness perception. By taking a thorough and meticulous approach, we hope to provide a more detailed and substantiated answer regarding the relationship between chemical components and sweetness perception in the beverage.

Our goal is to contribute valuable insights to the scientific understanding of flavor perception in coffee. Please note again that our research is still ongoing, and we look forward to sharing the comprehensive results once they are available.”

It changes depending on terroir, processing, and roasting: what is the most decisive stage for the final result in the cup?

“The coffee-making process is multifaceted, with each stage playing a crucial role in the final cup result. From terroir to roasting, every step has the potential to significantly influence the flavor and overall coffee experience. Even factors like the color of the coffee bag or the shape of the coffee cup can impact how we perceive the taste. Therefore, it is essential to have a comprehensive understanding of each stage and its relevance in order to create a unique and enjoyable cup for consumers.

However, the closer to the final cup (consumer), the room for variation becomes narrower.
While roasting is highly important for determining coffee flavor, it’s important to note that starting with defective beans severely limits the ability to craft a desirable cup. Hence, while roasting is significant, it is crucial to recognize the value of each stage and how they interact with one another.

Terroir encompasses climate, soil composition, and altitude, which all influence the growth and development of coffee plants. Different regions and microclimates produce distinct coffee flavor profiles, highlighting the significance of terroir.

Processing methods, such as washed and natural processing, also have a significant impact on coffee flavor. Natural processing, for example, can bring out fruity flavors. The choice of processing method greatly influences the final flavor and aroma characteristics. Roasting, undoubtedly, plays a critical role in shaping coffee flavor through chemical transformations, color changes, and aroma/flavor development.

So, while all stages are vital, identifying the most decisive stage for the final cup is subjective and dependent on factors such as desired flavor profile and individual preferences. Some argue that exceptional coffee starts with terroir and the quality of green beans, while others emphasize the importance of the roasting process in unlocking the beans full potential.

In conclusion, achieving the desired flavor profile in a cup of coffee requires a delicate balance and synergy between terroir, processing, roasting, and coffee preparation. It is the harmonious combination of these stages that contributes to the complexity and uniqueness of the coffee we enjoy.”

How can specialty coffee be used to create different taste experiences?

“Aligned with my previous response, specialty coffee provides diversity and opportunities to explore. There are countless of potential combinations for a coffee beverage: varieties/varietals, terroirs, harvesting techniques, processing methods, drying mechanisms, roasting profiles, grinding levels, extraction methods.

All these elements are reflected in the cup, i.e. material or intrinsic attributes, but you need also to bring into the experience those that are extrinsic, or information about the coffee (origin, producer, sustainability practices, fair pricing models, certifications, etc) to create more complex and compelling stories that enhance the tasting experience for the consumer. If you add careful consideration to other extrinsic elements like packaging, café ambient, cup colors/texture, you could be one step ahead to differentiate and create truly unique and crafted experiences that are distinctive and more valuable.”

Cordoba, from a chemical-sensory point of view, what have you discovered so far about the water used to make coffee?

Water quality plays a crucial role in the sensory experience of coffee. The composition of water can affect the extraction of compounds from coffee grounds and ultimately impact the flavor profile of the brewed coffee. While we acknowledge the significance of water, it’s important to note that our research has focused on other variables within coffee preparation, and we have used a standardized water quality for consistency.

In order to conduct a comprehensive investigation, we have followed the guidelines and recommendations established by reputable organizations such as the Specialty Coffee Association and have considered the research conducted by the Coffee Excellence Center in Switzerland. These sources provide valuable insights into the impact of water quality on coffee flavor and extraction.

To ensure reliable and reproducible results, it is necessary to control certain variables in our experiments; we can’t evaluate every single parameter that affects extraction processes. While we haven’t specifically examined the chemical-sensory aspects of water used in coffee preparation, we are aware of its role in coffee but didn’t include this experimental variable as part of our research.”

What are the new frontiers in science as far as your field of research is concerned? What remains or would you still like to explore further?

Cordoba: “Consumer preferences and research are constantly evolving, presenting exciting opportunities for exploration in my field of research. One prominent frontier is the integration of data science to analyze the vast amount of consumer-related data generated through digital platforms. By employing data science techniques, we can gain valuable insights into consumer patterns and preferences, deepening our understanding of what consumers truly desire.

The use of machine learning and artificial intelligence algorithms further enhances our ability to accurately predict and anticipate consumer preferences. Another captivating area of coffee research lies in the intricate chemical composition of coffee. Coffee consists of numerous compounds that contribute to its aroma, flavor, and overall sensory experience.

Through advancements in analytical techniques, we can now precisely identify and measure these compounds, providing valuable insights into how factors like origin, processing methods, and roasting techniques influence the flavors we find in our cup of coffee.

Moreover, we have to continue working towards correlating sensory analysis with chemical data to identify the specific compounds responsible for key flavor attributes such as fruity notes, floral aromas, or sweet, acidic, bitter undertones. This knowledge empowers us to develop more accurate flavor profiles, improve quality control measures, and even breed coffee varieties with specific desired flavor characteristics.

In addition, focusing on understanding how individuals perceive sensory attributes in coffee and how these perceptions may vary among different consumer groups might have a great potential. Genetics, individual tasting abilities, and cultural influences all shape our coffee experience. By comprehending these factors, we can develop sensory evaluation methods, training programs, and consumer studies that provide valuable insights into consumer preferences, contributing to the creation of unique and captivating coffee experiences.

To summarize, the integration of data science, advancements in chemical analysis, and exploration of sensory perception are fascinating frontiers in coffee research. These areas of study hold the potential to enhance our understanding of consumer preferences, refine flavor profiling techniques, ensure rigorous quality control, and ultimately create
unforgettable coffee experiences that cater to the diverse tastes and desires of coffee lovers.”


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