The researchers from the Polytechnic Institute of Bragança and the University of Porto, led by Jose Pinela, initiated a microwave-assisted extraction process which enabled the production of nutrient-rich extracts through the recycling of plant wastes. The antioxidant extracts were rich in functional phenolic acids and flavonoids, and can be used for food and feed industries.
“The production of natural extracts requires suitable processing conditions to maximize the preservation of the bioactive ingredients. Herein, a microwave-assisted extraction process was optimised,” wrote the researchers.
Several precise variables were important in producing high-quality extracts—temperature, ethanol concentration and solid/liquid ratio. The optimum processing conditions (t = 20 min; T = 180 dec C; Et = 0 percent; and S/L = 45 g/L) yielded tomato extracts with high potential as nutraceuticals and as active ingredients in the design of functional foods.
The study found the antioxidant retention was lower compared to standard commercial food additives, but these ingredients could still be incorporated in feed products, and used in the functionalisation and fortification of food. The production of tomato wastes for production of nutrient-rich antioxidant ingredients is a sustainable strategy, which can contribute to a bio-economy.
The food industry produces large volumes of wastes, which results from the production and consumption of food. These wastes pose potential severe pollution problems and represent a loss of valuable biomass and nutrients.
The recycling and reprocessing of food processing residues offers food manufacturers by-products which can be beneficial; as opposed to discharging it to the environment which leads to damaging environmental effects.