In USP testing, microparticles derived from unripe fruit have shown similar efficacy to the synthetic compound TBHQ found in processed foods and cosmetics. The results are published in the journal Food of the future (photo: researchers collection)
May 13, 2022
Karina Ninni | FAPESP Agency – Antioxidants are important substances in the food and cosmetic industry because they delay the oxidation of lipid-rich foods such as mayonnaise, margarine, moisturizers and the like. Most of the antioxidants currently in use are synthetic, and Brazil still uses products already banned in other countries, such as TBHQ (tert-butylhydroquinone).
In search of natural alternatives, a team of researchers from the University of São Paulo (USP) studied the phenolic compounds of acerola and was able to extract antioxidant microparticles from green fruits that are as effective as TBHQ. The goal of the FAPESP-supported study is to develop a process that can be easily implemented on an industrial scale. The latest results have been disclosed in the journal Food of the future.
“There are several studies proving the presence of antioxidant compounds in different sources. But how can we ensure that substances of interest and great potential for use can be produced commercially in a technically and economically viable way? Many studies in biochemistry are carried out on laboratory benches or with very small samples, with no provision for industrial use. Our goal is to work with the processes of obtaining products, ingredients in general, with the aim of their practical application, ”summarizes Thais Maria Ferreira de Sousa VieiraProfessor, Department of Agro-Industry, Nutrition and Food, Luis de Queiroz College of Agriculture (Esalq-USP).
With representative samples (5 to 10 kg of fruit) and using only water or ethanol as a solvent (petroleum derivatives were avoided due to their toxicity), the study sought to optimize processes to improve performance, i.e. recovery after – evaluate as many compounds of interest as possible and at the same time reduce energy costs and operating costs.
“The team members have already worked with acerola and have compared green and ripe fruit in previous studies, showing that green acerola contains more antioxidant compounds than ripe acerola. It happens that on the same tree there are ripe and unripe fruits that are collected together. Unripe fruits end up leaving the flesh not as visually appealing. So we understand that using these green fruits to produce a natural antioxidant is a good strategy,” he says. Bianca Ferraz Teixeirathe first author of the article and scholarship scientific initiation in FACESP.
Process and tests
Samples obtained from a major manufacturer in Junqueirópolis (SP) were washed and lyophilized (subjected to a process to extract water from food) for characterization and homogenization. The extract was obtained by adding water to lyophilized samples, then the material was centrifuged and filtered.
This extract has been sprayed into spray dryer [equipamento que promove a secagem do alimento por pulverização e é usada, por exemplo, na produção de leite em pó] and thus we got a microparticle. We chose spray dryer because this method is already widely used in industry. This allows the acerola extract to be converted into an antioxidant powder that can be stored, sold and used in a simple way without being oxidized. After all, it can replace TBHQ, which is also used in powder form, it does not spoil and mixes well with the product without causing color, taste or aroma changes,” explains Teixeira.
To test the effectiveness of the microparticles, the researchers made an oil-emulsifier-water emulsion similar to those found in some products, including mayonnaise, salad dressings, and cosmetics, and divided the samples into three groups: the first was supplemented with TBHQ, the second received acerola microparticles, and the third (control group) was left without any additive.
“We have added the concentration allowed by current legislation for a synthetic antioxidant and various concentrations of microencapsulated acerola powder. And we saw that the latter was just as effective as TBHQ at the same concentration,” says Teixeira.
Vieira explains that the test in the model system (water in oil) is ideal for exploring the possibilities of using the product and finding out at what concentration the acerola powder is effective. “Commercially produced natural antioxidants already exist. But it is useless to have an encapsulated natural product that requires a large amount to be effective, as cost is often an obstacle. The antioxidant also cannot change the appearance, color, or flavor of the final product. In this work, aroma analysis was conducted with tasters and there was no difference between the samples with the synthetic antioxidant and the acerola-based product from an organoleptic point of view.”
Teixeira recalls that acerola has a high concentration of ascorbic acid (vitamin C), which is not considered a phenolic compound but has high antioxidant activity. “The fruit also contains ferulic acid, chlorogenic acid, and coumaric acid. But the tests performed show that in the case of green acerola, ascorbic acid is most present, ”he says.
The researcher reiterates that the effectiveness of acerola is similar to that of synthetic antioxidants. “This was the first product we tested in the lab with the same characteristics. We used TBHQ as a beacon because it is a very effective substance. But in France, Japan and the United States, this synthetic antioxidant is practically no longer used. Therefore, finding a natural alternative that is so effective and easy to use is a real achievement.”
Article Replacement of synthetic antioxidants in food emulsions with acerola green microparticles (Malpighia marginalized) can be obtained at: www.sciencedirect.com/science/article/pii/S2666833522000181.