Abstract The objective of this study was to obtain and characterize a freeze-dried powder of taioba leaves (Xanthosoma taioba) as a source of bioactive substances and potential food applications. The fresh leaves were cooked and lyophilized for further analysis. Its bioactive contents expressed in flavonoids, ascorbic acid and total polyphenols were quantified. Total antioxidant activity (TAA) was determined by ABTS assays. The chemical composition via infrared spectroscopy (FTIR) and its microstructure were visualized by scanning electron microscopy (SEM). The bioactive contents of flavonoids, ascorbic acid and polyphenols were 17.15 mg/100 g, 58.3 mg/100 g and 24.15 mg Eq. of gallic acid/100 g, respectively. A high content of TAA was found. ABTS 37.35 (µg TE/g). The FTIR spectrum revealed high-intensity bands at 3350 cm-1, 2928 cm-1, 1637 cm-1, and 1055 cm-1 related to vibrations associated with typical bands of −OH groups present in cellulose membranes, hemicellulose, carbohydrates, lignin and water. The micrographs showed irregular structures of the ground leaves with a fibrous structure. These results indicate a high potential of this raw material in food formulations as a source of bioactives suitable for applications in various industrial segments.

Abstract Agroindustrial disposal generates tons of passion fruit albedo during pulp and juice processing. The reduction of this environmental pollution potential and its use involves research such as this one, which aims to determine the bioactive compounds in the passion fruit albedo (Passiflora edulis), its technological, functional potential and its morphological structures, aiming at food application. The methodologies applied followed internationally accepted and recommended guidelines. The results showed that the albedo flour obtained a yield of 9.76%, and from this, a semifine powder flour was prepared (75.8%), with 4.95% moisture, 40.72% reducing sugars, water activity of 0.37, pH of 5.29, total titratable acidity of 0.99 and total soluble solids of 1.5 °Brix. In addition, the presence of bioactive compounds such as polyphenols (18.88 mg AGE/100 g), flavonoids (13.51 mg/100 g), anthocyanins (1.74 mg/100 g) and chlorophyll b (69.65 mg/100 g) was evidenced, highlighting a considerable amount of vitamin C (377.36 mg/100 g) and pectin concentration (40.5%). In addition, the presence of bioactive compounds such as polyphenols (18.88 mg AGE/100 g), flavonoids (13.51 mg/100 g), anthocyanins (1.74 mg/100 g) and chlorophyll b (69.65 mg/100 g) was evidenced, highlighting a considerable amount of vitamin C (377.36 mg/100 g) and pectin concentration (40.5%).

Abstract The calcium oxalate content from two Amazonian amilaceous roots, Xanthosoma sagittifolium and Pachyrhizus tuberosus, before and after cooking were studied in the present work. Calcium oxalate raphides were observed by light microscopy in longitudinal sections from fresh tubers. The functional properties and physicochemical characteristics of isolated starches from both species were also investigated. Starches granules were observed with scanning electronic microscopy and presented a typical oval-circular shape, smooth surfaces and size ranging from 3.6 μm to 14 μm. Lower gel clarity, slightly high water-binding capacity, A-type starch structure and low values of crystallinity degree were determined in the isolated starches. High intensity bands related to vibrations of glucosidic bonds of polysaccharides were observed by infrared spectroscopy in both starches. Thermal degradation behavior data of the isolated starches reveled high initial decomposition temperatures. Thus, the studied cooked tubers presented low levels of calcium oxalates and are safe to be consumed as a boiled vegetable. Their isolated starches possess good functional characteristics to be applied as an ingredient to products in food industry.