CHARACTERIZATION OF CASSAVA PROCESSING WASTE CONTAINING PROTEIN AND LIPIDS FOR APPLICATION IN THE FOOD INDUSTRY

Agro-industrial waste has been researched as a sustainable alternative raw material for developing different bioproducts, such as food ingredients, biopolymers, biofertilizers, and biofuels. Significant amounts of wastewater (manipueira) are generated from the cassava flour industry, reaching between 300 and 600 L per ton of processed root. Manipueira is generated during cassava processing to obtain flour and starch in the step where the root mass, already washed, peeled, and grated, is pressed, releasing this liquid residue. Considering the functional biopolymers' composition, this study aimed to characterize the precipitate from cassava wastewater (PCW) regarding physicochemical, morphological, and particle size properties. Manipueira was gently donated by a cassava flour industry located in Santa Catarina. To obtain the PCW, the manipueira was boiled (100°C, 3 min) and centrifuged (25°C, 104 g, 10 min). Then, the precipitate was lyophilized (48 h under vacuum), mechanically macerated with a piston, packed in airtight bags, and stored in desiccators containing silica gel (25°C). The PCW was characterized by water activity, centesimal composition, granulometric profile, and morphology. The PCW presented water activity of 0.4 ± 0.03 characteristic value of dried materials. The centesimal composition in 100 g of sample was 6.7 ± 0.3 g of moisture, 4.8 ± 0.0 g of ash, 12.3 ± 0.1 g of proteins, 10.2 ± 0.2 g of lipids, 65.9 ± 0.6 g of carbohydrates, 2.7 ± 0.3 g of soluble fiber, 11.9 ± 0.2 g of insoluble fiber, 2.5 ± 0.3 g of total starch, and 1.0 ± 0.2 g of resistant starch. The high protein and lipid content can favor the PCW application in the food industry, possibly as a partial replacement for ingredients to increase the nutritional properties of food products. The SEM images showed irregular structures with different shapes ranging from fibrillar to slightly round, corroborating with the profile of varying particle sizes obtained in the granulometric distribution (32.3 ± 0.1%, 18.3 ± 1.8%, 17.3 ± 1.1%, and 10.2 ± 2.0% for particles with sizes of 177, 125, 105, and 420 µm, respectively). The FTIR spectra showed absorption bands attributed to –OH stretching and vibration of the hydrogen bond association, –CH asymmetrical and symmetrical stretching of aliphatic compounds, and elongation of anhydroglucose ring O–C stretch. These FTIR results are in line with the centesimal composition analyses. The high content of biopolymers in the PCW, especially protein and lipids, can contribute to the use of this residue both in the food industry and in the packaging industry, favoring its reuse for the development of new products or environmentally friendly material with higher added value, considering the precepts of the sustainability and circular economy.