Researchers reported that they obtained biologically active compounds, antioxidants, additives and natural food coloring from purple sweet potatoes. In order to identify and take advantage of this tuberous root, which contains significant amounts of antioxidants and natural dyes, throughout the year, at the Faculty of Chemistry (FQ) from UNAM, Arturo Navarro Ocaña, from the Department of Food and Biotechnology, identified bioactive compounds and processes for obtaining nutraceuticals from this and other traditional foods from Mexico.

Purple sweet potato (Ipomoea batatas (L) Lam. purple variety) is a species native to the country, widely distributed, especially in the central region. “We found it in the northern mountains of Puebla, in the Zongolic mountains in Veracruz, in Jalisco, Guanajuato and the state of Mexico,” he pointed out.

It is assumed that it reached the other side of the world by natural dispersal or by boarding the China Nao. It is the seventh most important food crop internationally; In Asia, it is widely accepted for consumption and is the main production region. China takes the first place in production and consumption, there it is recognized for its properties that maintain health.
But in Mexico, it is necessary to expand its properties and its constant intake, said the student who carries out enzymatic modification of natural antioxidants and bioactive compounds in the laboratory in order to use them on a large scale. We are looking for an integral use of resources, because in addition to the tuberous root, leaves and flowers (known as quelites) are also edible.

Since 2007, the year he returned from a sabbatical at the University of Barcelona, ​​Navarro began research with the natural pigments, anthocyanins, responsible for giving colors ranging from red to blue to fruits such as blackberries, blackberries, grapes and blueberriesas well as pigmented corn, purple sweet potato and some blue and purple flowers.

“Other pigments are carotenes, which give sunflowers and carrots shades of yellow to orange; and betalains, which color beets and the flowers and fruits of cacti, such as red prickly pear, capona and xoconostles. They are all colors, but they have different chemical structures,” he explained.

In addition to dyes that can be used to pigment dressings, desserts, drinks and industrialized food, the purple sweet potato is rich in starch, suitable for making flour and fermented drinks, with which the researcher and his students are already testing.

“We analyzed their composition, including leaves, flowers and stems, in order to know their biologically active compounds, their quantity and the conditions in which they are stored. We also developed pulp flour, and Andrea Torres, Master of Chemical Sciences, prepared healthy snacks from them, such as muffins that retain their original color, similar to those with red fruit, and they measured the amount of bioactive compounds they contain,” he commented.

This edible plant is nutritious and balanced because it has a lot of carbohydrates and proteins, some lipids, vitamins and minerals. In addition, it has bioactive compounds such as anthocyanins, chlorogenic acid, triterpenes, coumarins and alkaloids, which are secondary metabolites responsible for the protection and prevention of long-term diseases if consumed frequently, he pointed out.

The chemist recalled the traditional Okinawan diet, in which sweet potatoes are one of the main foods. “The population that consumes it in that area of ​​Japan has an average life expectancy of 87 years, one of the longest in the world, and good general health, according to scientific studies,” he emphasized.

The main contribution of this tuberous root to maintaining health is that it is a powerful antioxidant. “It contains anthocyanins and chlorogenic acids, which fight against oxidative stress and metabolic syndrome, improve eye diseases and prevent cardiovascular diseases; They are also substances that make it possible to control diabetes. It has recently been proven that they help in the recovery of short-term memory,” he pointed out.

Source: Faculty of Chemistry – UNAM