Coffee, in particular green robust or dark roasted coffee at up to 230 degrees Celsius, has many health-beneficial activities, says Dr. Eng. Joanna Grzelczyk, from the Lodz University of Technology, who studied these compounds.
The infusion obtained from coffee beans gives energy to more than half of Poles every day. In Poland, about 3 kg of coffee is consumed per capita per year. For comparison, the Finns, who drink the most coffee, consume 12 kg per person per year. What may be surprising, Italians, who are famous for their coffee culture, drink “only” 5 kg of coffee per person.
Health benefits of coffee
In the coffee production process, the pulp is mechanically removed from the ripe coffee fruit, and the green seeds obtained in this way are dried and roasted. Roasting takes place at a temperature of 180 to 250 degrees C and lasts from two to twenty-five minutes, depending on the desired degree of roasting. Coffee roasting, as well as other thermal processing of food, leads to a change in the chemical composition of the product. There is also a process called the Maillard reaction. The products of this non-enzymatic reaction between simple sugars and amino acids are, for example, melanoidins, responsible for the browning of roasted beans.
However, in addition to the positive effects of coffee roasting, such as improving its taste and aroma, there are also unfavorable phenomena – molecules with potentially harmful properties are formed, such as acrylamide or 5-hydroxymethylfurfural (5-HMF).
The health-promoting properties of coffee were studied by Dr. Eng. oanna Grzelczyk from the Institute of Food Technology and Analysis of the Lodz University of Technology, who, as part of a project funded by the National Science Centre, checked the health-promoting properties of coffee and how it is affected by the roasting process.
“I am a coffee lover, and I have always wondered if there is a grain of truth in the myths about coffee. Research on coffee absorbed me. The grant from the National Science Center allowed me to conduct interesting experiments and present the results at conferences, and to gain new cooperation, which resulted, among others, in a trip to internship to Canada at McGill University” – says Dr. Grzelczyk in an interview with the website Nauka w Polsce.
Coffee is a product rich in compounds from the group of polyphenols, which have a number of health-beneficial activities. They improve the functioning of the immune system, antimutagenic, neuro- and cardioprotective, antidiabetic. Roasting negatively affects the content of polyphenols in grains. hese compounds in the free form are characterized by greater biological activity than in the bound form.
Proven by a researcher from the Lodz University of Technology
As part of her research, Dr. Grzelczyk prepared extracts from arabica and robust coffee beans – from green beans as well as light and dark roasted ones, and then subjected them to in vitro digestion in an artificial digestive system. It turned out that the content of free polyphenols effectively increases during digestion, especially in the part of the system simulating the large intestine, and the presence of intestinal microorganisms has a positive effect on this process.
Dr. Grzelczyk conducted an analysis of the binding of substances contained in coffee extracts with receptors and enzymes. It proved that these extracts can inhibit the activity of e.g. monoamine oxidase A and regulate the activity of the PPARγ receptor. The first of these molecules is responsible for the breakdown of serotonin in the body, and its inhibitors are used as antidepressants. n particular, robust green coffee extract blocked the activity of monoamine oxidase A. Green coffee may therefore have potential antidepressant properties. The researcher adds that blocking monoamine oxidase activity also reduces the desire to eat carbohydrates.
The role of the PPARγ receptor is known in the pathogenesis of type 2 diabetes. Dr. Grzelczyk’s research shows that the active substances contained in coffee extract, especially green coffee, can positively affect the insulin sensitivity of tissues, and thus have a preventive effect against type 2 diabetes. In roasted coffee, the content of these active substances decreases.
Dr. Grzelczyk also studied the influence of coffee on the development of neurodegenerative diseases. It proved that the tested coffee extracts have the potential to prevent them, because they inhibit the activity of certain enzymes and have a protective effect on model nerve cells. Coffee also counteracts the formation of beta-amyloid deposits that are associated with Alzheimer’s disease.
Dr. Grzelczyk determined that all tested coffee extracts protect epithelial cells of the small intestine, i.e. enterocytes, against oxidative stress, which is conducive to carcinogenesis. Those from green coffee also protect the liver, and the higher the degree of roasting the beans – the weaker this effect was.
Although the researcher focused mainly on the health-promoting effects of drinking coffee – in coffee extracts, she also determined the content of acrylamide. This compound is formed during the processing of food products at high temperatures (e.g. roasting) and promotes the formation of gastrointestinal cancers. “There is more of it in lightly roasted coffee, and less in dark roasted coffee. However, these amounts are not such that daily consumption of coffee will cause cancer” – the researcher reassures.
Summarizing his research, Dr. Grzelczyk tells how – and what – to drink coffee to make the best use of its health-promoting potential: “green or dark roasted, at a temperature of up to 230 degrees C. Of course, without additives such as sugar.” And he emphasizes that green robust coffee contains more compounds beneficial to health than green arabica.
““People who tell me about the harmfulness of coffee, I repeat an important sentence: everything we consume, we must consume in moderation. Even excess water can be harmful” – the researcher says in an interview with Science in Poland.
We can consume 3 to 4 cups of coffee a day (a cup is about 150 ml) – he adds.
She used the obtained results to develop a food product with a potential health-promoting effect – ice cream with the addition of green coffee extract – which was submitted for patent.
