Quinoa (Chenopodium quinoa Willd.) has been nutritionally highlighted when compared to other grains. In recent years the research on this pseudocereal has increased. In this work, six quinoa samples were studied: three from Peru, one from Brazil and two commercial samples. The samples were physically and physicochemically characterized, including macro- and micronutrient analysis, phenolic compounds content and antioxidant activity. Black, red and white samples showed as main difference the size, weight, ashes and dietary fibre content. Black samples were the smallest and lightest and had the lowest starch content but presented the highest levels of ashes and dietary fibre. The protein content (16.9 %) in the white Brazilian variety was higher than the others. Red and black samples had the highest levels of most minerals analysed. The antioxidant capacity measured by the DPPH method was higher for black and red samples in comparison with the white ones. However, the white Brazilian variety showed a significantly higher antioxidant capacity measured by the ABTS assay. With regard to the phenolic content, a difference was found between the samples which ranged from 55.5 to 95.5 g GAE 100 g⁻¹. The colour of the grain was found as not related to a higher content of phenolic compounds. Because their compositions are generally similar to light-coloured grains, and in some parameters such as dietary fibre and content of some micronutrients are superior, the grains of dark-coloured quinoa varieties (RPP, BCP) would have to be explored to develop foods that take advantage of this colour diversity.

The presence of chemical contaminants in agricultural products is a continued food-safety challenge in Peru. This country has robust agriculture potential, but its output of fruits and vegetables is severely impacted by massive mining activities, as well as poor farming practices, including the use of polluted irrigation water, misuse of pesticides, and inadequate postharvest conditions. This review examines the current scientific knowledge on the levels of pesticide residues, heavy metals, and mycotoxins on crops produced in Peru. The available data shows that several crop varieties are contaminated with these classes of chemical contaminants, and at levels that exceed the national and international permissible limits. The abundance of chemical contaminants in produce indicates a relevant food-safety issue, which increases the risks of chronic human diseases, like cancer—a leading cause of death in Peru. Finally, this review presents recommendations to address these contamination problems in produce grown in the Andean country.

Olive leaves are agro-industrial waste that pose an environmental management problem. However, they contain polyphenolic compounds with important bioactive properties beneficial to human. This study aimed to evaluate the effectiveness of two extraction technologies (pressurized liquid extraction and ultrasound-assisted extraction) combined with green solvents (pure water, 15% ethanol, and 15% glycerol) at 50 °C and 70 °C. The goal was to obtain extracts with both antioxidant capacity and antihyperglycemic properties from olive leaves. Pressurized liquid extraction with 15% glycerol at 70 °C was the most effective method for obtaining extracts rich in total polyphenols (19.46 mg GAE/g dw), with an antioxidant capacity of 4.11 mg/mL (inhibition capacity: IC50) and 500.26 µmol TE/g dw. For both extraction methods at 70 °C, glycerol was more effective at recovering phenolic acids, stilbenes and secoiridoid; while ethanol was more effective for recovering flavonols and phenylethanoids. Oleuropein was the most important polyphenol extracted from both pressurized liquid and ultrasound-assisted extractions, with concentrations of 171.48 µg/g dw and 246.70 µg/g dw, respectively. The extract obtained from pressurized liquid extraction with 15% ethanol at 70 °C exhibited significant inhibition (70%) of α-glucosidase enzymes, similar to the reference drug acarbose. In contrast, these extracts showed low inhibitory activity against the α-amylase enzyme. These findings can be applied to the development of functional foods and nutraceutical supplements aimed at managing postprandial glycemic response, offering a natural alternative for supporting type 2 diabetes management.