Processing grains with technology developed at Unicamp increased the concentration of nutrients in soy extract
When it comes to producing foods richer in nutrients, it is necessary to take care of the impacts generated in the process. A technology developed at Unicamp for processing soybeans can improve its yield, increasing the nutritional value of the oilseed extract and reducing production waste by up to 85%. The experiments to obtain enriched soy extract (popularly known as soy milk) were carried out in the laboratories of the Faculty of Food Engineering (FEA Unicamp).
Soy contains essential amino acids and isoflavone levels that are higher than those of other legumes. Isoflavones are compounds associated with the reduction or prevention of various types of cancer, diabetes, hypertension, kidney disease and osteoporosis. However, the nutritious compounds remained in the okara, the solid waste from vegetable milk production. “In a preliminary assessment, it is possible to double the recovery of proteins and increase the recovery of isoflavones in soy milk by up to 50%”, estimates Louise Kurozawa, professor at FEA and inventor of the technology.
The invention, developed during food engineer Camila Penha's doctorate, completed in 2021 the results were protected by the Inova Unicamp Innovation Agency. In her research, Camila sought to recover proteins and isoflavones through a procedure that includes pre-processing soybeans with the application of a mix of specific enzymes.
At this stage, it was found that the action of the enzyme complex also increased the yield of the extract and reduced the amount of waste generated. “The enzymes work to break down the fibers that make up the soybean cell wall. This results in the release of compounds present inside the cell matrix”, says Camila. The result is a process with greater recovery of proteins and isoflavones in the soy extract, favoring the formation of phenolic compounds such as aglycones, which are more easily absorbed by the body.
Processing improvements
Brazil is among the largest soybean producers in the world. The country harvested 124 million tons until June this year, according to the National Supply Company (Conab). Soy extract is used in the composition of drinks, tofu, margarine, creams and other industrialized products. Okara, in turn, is generated in the grain processing process. The starting point for Camila's research, edible pomace is rich in nutrients, but has low commercial value. Furthermore, as it deteriorates quickly, the waste needs refrigeration to be reused. It is mainly intended for animal feed, but also applied, on a smaller scale, in the production of foods such as hamburgers and cookies. “Okara treatment generates costs for companies and losses that can be minimized with the application of technology, because it improves the initial stages of soybean processing,” says Camila.
To produce the enriched extract, the researchers used a multi-enzyme complex that is already used by the food industry. Carbohydrase-type enzymes were applied in the pre-processing of soybean paste and increased the recovery of proteins present in the grains from 42% to 83% and of isoflavones from 59% to 93%. “The technology recovers nutrients lost in the residue in conventional processes and directs them to the product, something very relevant from the point of view of food safety”, explains Louise.
The work resulted in a patent application for the method developed. “The idea is to offer the industry an optimized process for producing water-soluble soy extract”, adds the professor. The final product was also sweeter, which could help reduce the food industry's use of sweetening additives. “By breaking down fibers, we also facilitate the formation of small sugars that are soluble in water,” says Camila. However, new sensory research and partnerships are still needed to verify whether the results will be maintained with the increase in production scale.
This text was originally published on the Innovates Unicamp.
