Sicana odorifera is a native fruit of South America large in size. Its dark-colored skin constitutes a useful byproduct for obtaining bioactive molecules because it is rich in polyphenolic compounds, such as anthocyanins. Obtaining appropriate extracts for obtaining anthocyanins can be useful for multiple applications in the food industry or for obtaining phytopharmaceuticals. In this work, the fruit and its peel composition were evaluated, an anthocyanin extraction system was designed and optimized, and the extract obtained was characterized. The peel composition of S. odorifera ripe fruits from the black accession growing in Paraguay was rich in polyphenol compounds and anthocyanins. Ultrasound-assisted extractions of total anthocyanins were studied, and the extraction variables were optimized. First, a screening design was considered to analyze time, pH, liquid–solid ratio, solvent concentration, and temperature. From the screening design, the significant variables were considered in a Box–Behnken design, and a response surface methodology was applied. The resulting total anthocyanin extract was characterized by UPLC-DAD-MS / MS-ESI. The most efficient system for the extraction of anthocyanins from the peel was at 15 min, 20 °C, pH = 6, 60% ethanol, and 80 mL/g of liquid–solid ratio. The highest concentration obtained was 61.908 mg C3G/g peel extract. In the extract, 12 main compounds were tentatively identified, including five anthocyanin derivatives, five flavonol derivatives, and two flavonol aglycones. This study provides information for the obtention of an anthocyanin-based dye from black kurugua peel, possibly useful for future applications as a natural colorant in high-added-value foods due to its antioxidant characteristics.

The “Kurugua” (Sicana odorifera) is a native fruit that demonstrates attractive nutritional, coloring, flavoring, and antioxidant properties. The main by-products from the processing and consumption of kurugua fruit are epicarp and seeds. In this work, the properties of the seeds of S. odorifera were evaluated. The nutritional composition of the fruit seeds was determined through AOAC official methods and UHPLC-ESI-MS/MS profiling. The antioxidant activities were determined using in vitro methods, and the acute toxicity and hepatoprotective properties were investigated in Swiss albino mice. Quercetin derivatives and cucurbitacins were the main phytochemicals in the seeds’ methanolic extract and demonstrated some biological activities. GC-MS analysis revealed the essential fatty acids linolenic and linoleic as the main compounds present in seeds oil. The methanolic extract significantly reduced the serum levels of glutamic-pyruvic transaminase (GPT) and glutamic-oxaloacetic transaminase (GOT) in mice with induced hepatotoxicity (GPT p < 0.05; GOT p < 0.001) at the minor concentration tested (100 mg/kg EMSo). The results suggest that the S. odorifera seeds as by-products show potential use as a source of phytochemicals and in the production of oils with application in food supplements and nutraceuticals. Their integral use could contribute to waste reduction from kurugua fruits processing within the food safety and environmental sustainability framework.

Prosopis alba and Prosopis chilensis, popularly called carob trees in the South American Chaco, are arboreal species. Carob fruits are an ancestral food for human consumption, mainly in the form of flour. In recent years, the study of carob trees in Paraguay has been based on the development of silvo-pastoral systems for livestock or as animal feed; very little is known about the compositional characteristics of the different varieties of carob that are part of the food systems, and that are used for the production of flours. Samples of flour from three autochthonous varieties of carob trees from the Central Chaco are evaluated for human consumption as a potential food ingredient in processed foods. They are evaluated for nutritional contribution, antioxidant potential and the preliminary evaluation of safety at the microbiological level. Official AOAC methods were used. The carob flour samples presented low humidity (less than 6%) and water activity (less than 0.45). The flours of the three species analyzed presented significant differences in their content of carbohydrates, lipids, proteins, dietary fiber and, consequently, in their caloric value, with a high content of polyphenols and antioxidant potential detected by ABTS. Presence of mesophilic aerobes, total coliforms and yeasts in the samples was observed. These results demonstrate the great food potential of carob flour from the Paraguayan Chaco, and indicate the need to address the food safety aspects of this type of wild-harvested food, to enhance their added value as ingredients for foodstuffs in the diet of regional populations.

Summary: The aim of this study was to evaluate the physicochemical characteristics, centesimal composition and antioxidants of the Sicana odorifera pulp and the antioxidant potential of the seeds and fruit peel harvested in a culture of the city of San Lorenzo, Paraguay. These fruits harvested in Paraguay present an antioxidant potential, interesting for food industry, especially in a ripe and semi-ripe state, where the highest content of vitamin C and total phenols was observed, as well as the total antioxidant capacity (ABTS).

Sicana odorifera seeds, from an ancestral Cucurbita growing in Paraguay, possess important biowaste after fruit pulp use. However, there are reports that its infusions can reduce and cure the symptoms of viral diseases such as hepatitis, denoting its medicinal properties. The recovery of nutrients and bioactive molecules from its bio-residues has potential uses in the industrial sector with high added value as functional food ingredients. In S. odorifera species, although it is not a fruit for mass consumption, it is precisely the lack of a market for its biowaste that has limited its integral use. Based on this, the centesimal composition, oil characterization, and fatty acids profile of the kurugua seeds from two accessions (atropurpurea (black) and reddish) were studied. Kurugua seeds have been subjected to a cold extraction with a hydraulic press from dried whole seeds, and ISO and AOCS standard methods were used for analytical determinations. The major components in the centesimal composition of kurugua seeds were lipids, dietary fiber, and proteins. The oils presented iodine, saponification, and refractive indices characteristic of preferentially polyunsaturated oils. The major component in the fatty acid profile was linolenic acid, an important essential fatty acid in the diet. Although the characteristics of kurugua oil, demonstrate its potential application in the food industry as a polyunsaturated oil, source of essential fatty acids, future studies on stability and sensory analysis for food applications are suggested, with great possibilities for the food safety framework.

The aim of the present work was to study the effect of the drying process conditions on the antioxidant properties of the integral fruit of kurugua (Sicana odorifera Naud.). The experiments showed that the antioxidant activity of fresh samples of whole kurugua could vary significantly depending on the fruit batch used. The statistical analyses showed no significant differences in antioxidant activity among the drying conditions studied. However, it is important to highlight that the drying process conducted at 80 °C and at an average air speed of 5.8 m/s presented the lowest cost (2.2 USD kW/h), and after 10 h, the raw material reached an aw level of 0.297, which is enough to inhibit the growth of microorganisms. As it is known, a low aw allows for a longer shelf-life of a product and prevents the proliferation of molds and yeasts. There was no significant difference in the concentration of β-carotene between drying times; nevertheless, the resulting flour showed a decrease in luminosity and color variation (b*) with respect to the fresh samples, with a typical browning due to the effects of temperature and air drying. The influence of the drying conditions on the integral kurugua flour is discussed in order to obtain the best dry product. A field of work has opened for future research on the sensory profile and its potential applications.