Maillard reaction is the principle contributor to the antioxidant capacity of coffee brews ......

Food scientists at the University of British Columbia have been able to pinpoint more of the complex chemistry behind coffee's much touted antioxidant benefits, tracing valuable compounds to the roasting process.  Yazheng Liu and Prof. David Kitts found that the prevailing antioxidants present in dark roasted coffee brew extracts result from the green beans being browned under high temperatures.

Liu and Kitts analyzed the complex mixture of chemical compounds produced during the bean's browning process, called the "Maillard reaction (a chemical reaction between an amino acid and a reducing sugar, usually requiring heat). The term refers to the work by French chemist Louis-Camille Maillard who in the 1900s looked at how heat affects the carbohydrates, sugars and proteins in food, such as when grilling steaks or toasting bread. Previous studies suggested that antioxidants in coffee could be traced to caffeine or the chlorogenic acid (see structures above and below respectively)  found in green coffee beans, but the present results clearly show that the Maillard reaction is the main source of antioxidants claims the researchers.  Researchers conclude that that coffee beans lose 90 per cent of their chlorogenic acid during the roasting process, LFS food science professor and director of the Food, Nutrition and Health program.

Ref : Yazheng Liu and David D. Kitt, Food Research International.

Daily dose of coffee could help reverse non-alcoholic fatty liver disease

Adding coffee to the diet of people with non-alcoholic fatty liver disease (NAFLD) could help reverse the condition, according to a new study conducted in mice presented at The International Liver Congress 2016 in Barcelona, Spain.

The study found that a daily dose of coffee (equivalent to six cups of espresso coffee for a 70kg person) improved several key markers of NAFLD in mice that were fed a high fat diet. These mice also gained less weight than others fed the same diet without the dose of caffeine.

The scientists also showed how coffee protects against NAFLD by raising levels of a protein called Zonulin (ZO)-1, which lessens the permeability of the gut. Experts believe that increased gut permeability contributes to liver injury and worsens NAFLD. People suffering from NAFLD can develop scaring of the liver, also known as fibrosis, which can progress to a potentially life-threatening condition known as cirrhosis.

"Previous studies have confirmed how coffee can reverse the damage of NAFLD but this is the first to demonstrate that it can influence the permeability of the intestine," said Vincenzo Lembo, at the University of Napoli, Italy and study author. "The results also show that coffee can reverse NAFLD-related problems such as ballooning degeneration, a form of liver cell degeneration."

Researchers analysed three different groups of mice over a 12 week period. Group one received a standard diet, group two had a high fat diet and group three was given a high fat diet plus a decaffeinated coffee solution.

Coffee supplementation to a high fat diet significantly reversed levels of cholesterol (p<0.001), alanine aminotransferase (an enzyme which levels increase in the blood when the liver is damaged) (p<0.05), amount of fat in the liver cells (steatosis) (p<0.001) and ballooning degeneration (p<0.05). The combination of coffee and a high fat diet also reduced weight gain over time (p=0.028) in the mice. The study results suggest that coffee supplementation could cause variations in the intestinal tight junctions, which regulate the permeability of the intestine.

Daily dose of coffee could help reverse non-alcoholic fatty liver disease: Adding coffee to the diet of people with non-alcoholic fatty liver disease (NAFLD) could help reverse the condition, according to a new study conducted in mice presented at The International Liver Congress 2016 in Barcelona, Spain.

Seeds of tropical shrub guarana contain ten times more amount of catechins than green tea

 

In continuation of my update on catechins. 

The millions of people who consume green tea all over the world benefit from the catechins it contains. Catechins are a class of chemical compounds with anti-oxidant and anti-inflammatory properties, among other healthy ingredients. Researchers at the University of São Paulo's Public Health School (FSP-USP) have discovered that guarana (Paullinia cupana) is a worthy competitor, at least as far as catechins are concerned: the seeds of the tropical shrub, used in fizzy drinks that are among the most popular in Brazil, as well as in over-the-counter supplements, contain more than ten times the amount of catechins found in green tea.

 Catechins

A clinical trial with healthy human volunteers has demonstrated that guarana is a rich source of catechins, which, when properly absorbed, reduce the oxidative stress associated with the development of neurodegenerative and cardiovascular disorders, as well as diabetes, cancer, inflammation and premature aging due to cell death, among other conditions harmful to health and wellbeing.

"Guarana has always been seen above all as a stimulant, especially by the international scientific community, because of its high caffeine content. We also found few Brazilian scientific studies that seek to identify other biological effects of guarana," said Lina Yonekura, the principal investigator for this research and currently an assistant professor at Kagawa University's School of Agriculture in Japan. "This pioneering assessment of the absorption and biological effects of its catechins in human volunteers should foster interest in guarana as a functional food on the part of scientists, the market, and society in general."

The paper with the results of the study is featured on the cover of the latest issue ofFood & Function, published by the Royal Society of Chemistry in the United Kingdom as one of the "Hot Articles in Food & Function 2016.

The month-long study was conducted in two stages. After selecting volunteers who were healthy but slightly overweight and with a moderately elevated risk of cardiovascular disease, the researchers measured baseline parameters on the first day and evaluated the same items again on day 15 after a the implementation of a controlled diet.

The participants were then asked to take guarana at home every morning before breakfast for the next fortnight. They were given bottles containing guarana seed powder and instructed to prepare a daily drink with the contents of one bottle (3 g of guarana powder) in 300 mL of water.

This procedure ensured that each participant acted as his or her own control. The researchers compared the same volunteers' blood tests at different times to avoid the influence of variability between individuals. The acute effect of guarana was measured one hour after the participants drank the solution on day 1 and day 15. The prolonged effect was assessed after overnight fasting on the same days.

The researchers assessed the extent to which guarana affected oxidative stress markers during the two-week intervention period. They also performed a detailed study to evaluate the subjects' absorption of catechins and their metabolites, as they had found no information in the scientific literature on the bioavailability of these compounds in guarana.

The oxidative stress markers included oxidation of low-density lipoprotein (LDL), popularly known as bad cholesterol. LDL is essential to an organism's proper functioning because it is the main particle that carries cholesterol to cells. Cholesterol is a structural component of all cell membranes and is used to manufacture steroid hormones (estrogen and testosterone). When oxidized, however, LDL causes atherosclerosis and increases the risk of cardiovascular disease. The tests performed by Yonekura's team showed an increase in oxidation resistance of the LDL in the blood samples taken from the volunteers after they drank guarana.

They also performed a comet assay, also called single cell gel electrophoresis (SCGE), a technique for quantifying and analyzing DNA damage in individual cells due to various factors, including oxidative stress. In this case, lymphocyte DNA in blood samples taken one hour after guarana intake was less damaged than expected when submitted to an oxidizing environment, indicating the presence of anti-oxidant substances or enhanced performance of the lymphocytes' enzymatic anti-oxidant system.

"All these markers depend on the presence of catechins in the bloodstream," Yonekura said. "The improvement in the parameters we assessed was associated with a rise in the concentration of plasma catechins after guarana intake, showing that guarana was indeed responsible for this effect."

Moreover, she went on, the guarana catechins strengthened the cells' native anti-oxidant enzymes, especially glutathione peroxidase, catalase, and superoxide dismutase, which combine to convert superoxide into peroxide and finally into water, protecting cells from the oxidative damage caused by their own metabolism of outside factors.

The tests showed increased glutathione peroxidase and catalase activity both shortly after guarana ingestion and on the following day.

"These results are exciting, suggesting that the bioavailability of guarana catechins is equal to or greater than that of green tea, cocoa and chocolate catechins," Yonekura said. "In fact, their bioavailability was sufficient to have a positive effect on plasma anti-oxidant activity, protect erythrocyte DNA, reduce plasma lipid oxidation, and increase anti-oxidant enzyme activity. We hope the results lead to heightened interest in guarana as the species is native to the Amazon, and Brazil is practically the only country that produces it on a commercial scale."

Daily dose of coffee could help reverse non-alcoholic fatty liver disease

Adding coffee to the diet of people with non-alcoholic fatty liver disease (NAFLD) could help reverse the condition, according to a new study conducted in mice presented at The International Liver Congress 2016 in Barcelona, Spain.

The study found that a daily dose of coffee (equivalent to six cups of espresso coffee for a 70kg person) improved several key markers of NAFLD in mice that were fed a high fat diet. These mice also gained less weight than others fed the same diet without the dose of caffeine.

The scientists also showed how coffee protects against NAFLD by raising levels of a protein called Zonulin (ZO)-1, which lessens the permeability of the gut. Experts believe that increased gut permeability contributes to liver injury and worsens NAFLD. People suffering from NAFLD can develop scaring of the liver, also known as fibrosis, which can progress to a potentially life-threatening condition known as cirrhosis.

"Previous studies have confirmed how coffee can reverse the damage of NAFLD but this is the first to demonstrate that it can influence the permeability of the intestine," said Vincenzo Lembo, at the University of Napoli, Italy and study author. "The results also show that coffee can reverse NAFLD-related problems such as ballooning degeneration, a form of liver cell degeneration."

Researchers analysed three different groups of mice over a 12 week period. Group one received a standard diet, group two had a high fat diet and group three was given a high fat diet plus a decaffeinated coffee solution.

Coffee supplementation to a high fat diet significantly reversed levels of cholesterol (p<0.001), alanine aminotransferase (an enzyme which levels increase in the blood when the liver is damaged) (p<0.05), amount of fat in the liver cells (steatosis) (p<0.001) and ballooning degeneration (p<0.05). The combination of coffee and a high fat diet also reduced weight gain over time (p=0.028) in the mice. The study results suggest that coffee supplementation could cause variations in the intestinal tight junctions, which regulate the permeability of the intestine.

Daily dose of coffee could help reverse non-alcoholic fatty liver disease