Where Do Berries Get Their Colour?
Fruit and Berry Growers Union hmlry.fi
14 Aug. 2019
The berries of late summer are tasty, but also beautiful to see. For plants, the purpose of their colours is to attract animals to both eat the berries and spread the plant seeds. The colours also protect the plants from excessive solar ultraviolet (UV) radiation. These pigments are currently the objects of a great wealth of research because they are believed to have numerous health benefits for humans as well. The berry shades of orange, yellow and red come from carotenoids, which are liposoluble (i.e. fat-soluble) compounds. There are approximately 600 different known kinds of such. The shade of a berry is generally formed by the interaction of several different carotenoids. The best-known carotenoid is beta-carotene, which functions as a precursor to vitamin A. Vitamin A is especially important to eye health. Among berries, the colour orange Sea-buckthorn contains the greatest variety of carotenoids, including beta-carotene. Strawberries contain a carotenoid called lutein.
The shades of red, blue and violet come from anthocyanins. These are water-soluble pigments belonging to the class of flavonoids. There are at least 500 different known compounds of such pigments. The blue colour of bilberries and blackcurrants comes from an anthocyanin called delphinidin. An anthocyanin called pelargonidin is found in strawberries. Anthocyanins are also found in redcurrants, raspberries and apple pulp. In the case of the Pekka variety of apples, anthocyanins are found in the flesh of the fruit as well.
The sun brings colour to the surface.
Anthocyanins develop in the berry as it ripens. At the same time, the amount of chlorophyll decreases. Have you noticed that apples and strawberries first redden on the side exposed to the sun? Preparing anthocyanins demands the presence of abundant sunlight and sugars. The colour of many anthocyanins may change according to acidity. In an acidic environment, anthocyanins are generally red, but as the pH rises to neutral, the colour changes through violet to blue. In an alkaline environment, some anthocyanins are completely colourless. Thus, you can try to fade a bilberry stain, for example, with a solution of baking soda and water.
Both carotenoids and anthocyanins are believed to function as antioxidants in the body, meaning that they protect the cells from the adverse effects of oxygen. The health benefits of pigments have been the objects of a great number of studies in recent years and the findings on these benefits are promising, for example, in terms of cancer and cardio-vascular disease prevention. Berries retain their colour quite well when heated or frozen. It is advisable to eat the largest possible variety of different coloured berries. The recommended serving is two decilitres per day.
“The More Colour, the Better!” – Scientists Discover New Health Benefits in Berry Pigments
According to a study conducted at the University of Eastern Finland, the pigments of berries may potentially be developed into new medicines, for example, for the treatment of colorectal cancer.
“The more colour the berry contains, the better,” says Minna Rahnasto-Rilla, Doctor of Pharmacy at the University of Eastern Finland.
Previously, it was known that berries have abundant health benefits, but now scientists have made new observations about the wholesomeness of the pigments occurring naturally in berries.
A study by the University of Eastern Finland provides evidence that according to the new data, berry pigments known as anthocyanins may potentially be developed into new medicines, for example, to treat pancreatic and colorectal cancers.
According to the study, anthocyanins increase the function of the sirtuin 6 enzyme in cancer cells. The regulation of this enzyme could open up new avenues for cancer treatment.
It is advisable not to strain off the wholesome pulp.
Pigments are found in numerous berries growing in Finland, but especially high quantities of such are found in bilberries, blackcurrants and lingonberries. According to the scientists, these compounds are found in the berry pulp in particular. The pulp is very wholesome, so it is advisable not to strain it off, for example, when cooking.
“So, not to worry if bilberries blacken your teeth!” laughs Dr. Rahnasto-Rilla. “It’s good for you.”
Freezing berries reduces their quantity of wholesome ingredients, as does the process of ageing, but without destroying these completely.
“Drying is a good way to preserve berries,” continues Dr. Rahnasto-Rilla. “The wholesome ingredients will keep better that way.”
Sirtuin-related research has been conducted at the University of Eastern Finland already since the early 2000s. At the time, scientists began searching for new pharmaceutical substances, which might be used to regulate sirtuins. This research is still in its early stage, but according to Dr. Rahnasto-Rilla and Dr. Lahtela-Kakkonen, the recent data lays a foundation for the development of new medicines.
The Finnish-American study included researchers from the University of Eastern Finland and the National Institute on Ageing in the US.