Generales

By: Jennifer Restrepo de la Pava-Journalist
With an edible coating made from starch extracted from avocado seeds, scientists from UdeA seek to reduce oil and acrylamide content absorption while frying potatoes. Aclyramide is a carcinogenic and neurotoxic substance produced by the interaction of reducing sugars and amino acid present in food during baking or frying processes.

Development and formulation of the coating for fried potatoes. Photos: courtesy of Grupo Bioali.

Have you ever eaten a fried potato that was too toasted, burned or bitter? While making some foods such as bread, cookies, toast, panela, coffee and French fries - whether baked or fried at temperatures above 120 °C - a thermal degradation produces toxic chemicals such as acrylamide.

Acrylamide is a chemical contaminant produced by food processing. The World Health Organization classified it as a carcinogenic substance; that is, it generates or favors the appearance of different types of cancer. It is also considered mutagenic - it affects the DNA of a cell - and neurotoxic - it inhibits or alters the functions of the nervous system - and causes reproductive problems.

This substance "is formed mainly by the interaction of reducing sugars present in food and an amino acid called asparagine when heated. A higher oil temperature favors the appearance of this compound," explained Óscar Alfonso Vega Castro, coordinator of the Food Biotechnology research group (Bioali) at Universidad de Antioquia. This team sought alternatives for food processing at the local level. It must be considered that frying and baking food (cookies, potatoes and others) is ubiquitous in homes and streets of Colombia.

Although she is not part of the research team, Alma Mater consulted Briana Davahiva Gómez Ramírez, MSc in Science, Technology and Food and Human Nutrition and Food Sciences. We asked her about the processing of this toxic compound. "Most acrylamide is discarded by our system, especially in urine. Some research speaks of excretion of 95%, while other reports speak of 80%. It is still not clear. In reality, an accumulation or high consumption is unnecessary if the substance damages any nitrogenous base of the DNA; that is to say, it can cause carcinogenic, mutagenic or neurotoxic processes."

She added that another route of acrylamide formation is by the oil's smoke or vapor. Inhaling it in very high concentrations can cause confusion, lethargy and other neurological symptoms.

Considering the health complications caused by acrylamide in food, the European Commission has published Regulation (EU) 2017/2158, which establishes mitigation measures and reference levels in different food groups, including fried potatoes. This regulation states that specifically fried potatoes should contain levels of this compound below 750 μg/ kg (micrograms per kilogram).

In this regard, the analyses carried out by the Bioali group on different portions of fried potatoes purchased in the streets of Medellín determined that these contain an average of 200 micrograms of acrylamide per kilogram of potatoes, but this value could be higher.

The acrylamide values in fried potatoes with the coating formulated with starch extracted from avocado seeds and essential oregano oil was 99 μg/ kg. It is a reduction of almost 45% of the acrylamide in fried potatoes. "This is positive news, as it complies by a wide margin with the European regulation," explained Dr. Óscar Vega, who added that the coating does not affect the sensory part of the potatoes; that is, it does not change their flavor.

Hass Protector

In the research "Characterization and application of a starch coating extracted from the seed of the avocado (Persea americana L cv. Hass) as an alternative to reduce acrylamide content in French fries", the Bioali Group discovered that avocado seed starch is an ideal coating to "protect potatoes." It reduces fat absorption and decreases acrylamide formation, which provides a protective effect since the starch gelatinizes. This gelatinization prevents water leakage and reduces oil absorption in potatoes.

This avocado starch is the result of processing the seed.

Poltec S.A.S., a partner company in the project, characterized the starch extracted from the avocado seed. The company determined that the starch can have different applications, such as in fabric dyes and the development of polymers, specifically coatings. "The coating could be aimed at manufacturers of pre-frozen potatoes. We think it could be useful for small and medium-sized companies and fried potato sellers," said Diana Carolina Bedoya Cañaveral, marketing coordinator of Poltec S.A.S.

Although the results are promising, some challenges remain. According to Vega Castro, the first challenge is to improve the process of extracting starch from avocado seeds and to strengthen the regulation of acrylamide content in food in Colombia. Although Invima has conducted some studies on acrylamide content in food, it has not issued a specific standard, added Professor José Contreras, co-researcher of the project.

Finally, other coating properties remain to be studied, such as water vapor permeability and its possible application in other foods, according to Diana Granda, researcher of the Bioali group. For Poltec S.A.S., it is essential to continue working with the University to develop solutions that support different national industries that can use starches from various sources in their production chains.

The Bioali group seeks to improve seed extraction to increase the raw material yield. Avocado growers from Marinilla, Antioquia, participate in this process through the agro-technological citadel in that municipality. The project trained two undergraduate students of food engineering: Milanyela Ramírez and Leimin Blandón. It was also supported by Poltec, a company dedicated to designing and manufacturing solutions in food textures, the Corporación Universitaria Americana and the Institute of Food Science, Technology and Nutrition (ICTAN-CSIC), from Madrid, Spain.

Universidad de Antioquia's Vice-Presidency for Research supported the scientific dissemination of the results through the Fund for the Democratization of Academic Knowledge.

New oil, instead of reduced oil, is recommended to minimize contaminants during the frying of potatoes. Use thicker potatoes and wash them thoroughly to reduce the content of starches, which are composed of sugar chains.