The use of sensors in critical areas for human development such as water, food, and health has increased in recent decades. When the sensor uses biological recognition, it is known as a biosensor. Nowadays, the development of biosensors has been increased due to the need for reliable, fast, and sensitive techniques for the detection of multiple analytes. In recent years, with the advancement in nanotechnology within biocatalysis, enzyme-based biosensors have been emerging as reliable, sensitive, and selectively tools. A wide variety of enzyme biosensors has been developed by detecting multiple analytes. In this way, together with technological advances in areas such as biotechnology and materials sciences, different modalities of biosensors have been developed, such as bi-enzymatic biosensors and nanozyme biosensors. Furthermore, the use of more than one enzyme within the same detection system leads to bi-enzymatic biosensors or multi-enzyme sensors. The development and synthesis of new materials with enzyme-like properties have been growing, giving rise to nanozymes, considered a promising tool in the biosensor field due to their multiple advantages. In this review, general views and a comparison describing the advantages and disadvantages of each enzyme-based biosensor modality, their possible trends and the principal reported applications will be presented.

High-pressure processing (HPP) is a nonthermal technology used for food preservation capable of generating pasteurized milk products. There is much information regarding the inactivation of microorganisms in milk by HPP, and it has been suggested that 600 MPa for 5 min is adequate to reduce the number of log cycles by 5–7, resulting in safe products comparable to traditionally pasteurized ones. However, there are many implications regarding physicochemical and functional properties. This review explores the potential of HPP to preserve milk, focusing on the changes in milk components such as lipids, casein, whey proteins, and minerals, and the impact on their functional and physicochemical properties, including pH, color, turbidity, emulsion stability, rheological behavior, and sensory properties. Additionally, the effects of these changes on the elaboration of dairy products such as cheese, cream, and buttermilk are explored.

Oregano (Poliomintha longiflora) essential oil (Ooil) is a product of high commercial value and many applications, including chemotherapy. Aiming to achieve the best use of this resource, the present study focuses on the characterization of separated fractions of Ooil by fractional vacuum distillation at low pressure. Four fractions (F1–F4) and undistilled oil (Unoil) were separated from Ooil and analyzed for their chemical composition and biological activities, such as antioxidant and antimicrobial activities. Gas chromatography–mass spectrometry shows differences in the composition among the fractions and Ooil. The amount of monoterpenes oxygenated (MO), sesquiterpenes hydrocarbon (SeH) and monoterpenes hydrocarbon (MH) varied between the fractions in ranges of 1.51–68.08, 3.31–25.12 and 1.91–97.75%, respectively. The major concentrations of MO and SeH were observed in F4 and Unoil. On the other hand, the highest concentrations of MH were found in F1 and F2, while the lowest were in F4 and Unoil. These results were correlated with the biological activity. Free-radical scavenging activity varied among fractions, with F4 and Unoil showing the highest activity. The antimicrobial test showed that F4 and Unoil had the highest activity in almost all cases. The correlation between the variables studied in the different fractions allows the definition of the particular properties for each one of them.

Several factors have the potential to influence microalgae growth. In the present study, nitrogen concentration and light intensity were evaluated in order to obtain high biomass production and high phycoerythrin accumulation from Porphyridium purpureum. The range of nitrogen concentrations evaluated in the culture medium was 0.075–0.450 g L⁻¹ and light intensities ranged between 30 and 100 μmol m⁻² s⁻¹. Surprisingly, low nitrogen concentration and high light intensity resulted in high biomass yield and phycoerythrin accumulation. Thus, the best biomass productivity (0.386 g L⁻¹ d⁻¹) and biomass yield (5.403 g L⁻¹) were achieved with NaNO₃ at 0.075 g L⁻¹ and 100 μmol m⁻² s⁻¹. In addition, phycoerythrin production was improved to obtain a concentration of 14.66 mg L⁻¹ (2.71 mg g⁻¹ of phycoerythrin over dry weight). The results of the present study indicate that it is possible to significantly improve biomass and pigment production in Porphyridium purpureum by limiting nitrogen concentration and light intensity.