Development of Araticum (Annona crassiflora Mart.) jams: evaluation of physical, microbiological, and sensorial stability in different packages.

Araticum is an exotic fruit with unique sensory features and also high nutritional value characteristics. This study aimed to develop araticum jams with substitution of commercial pectin for passion fruit albedo, as well as to evaluate its physical, microbiological and sensorial stability during storage in polyethylene and polypropylene packages. Samples were analyzed at 25 and 35 °C for 130 days. During the storage the values of pH (3.5-4.9), titratable acidity (0.27-0.62%), color (L* 20.56-28.49, a* 1.32-7.03, and b* 1.32-9.29), chroma (1.86-11.65), hue (0.60-1.03), soluble solids (68-79.70 ºBrix), reducing sugars (12.60-60.30%), non-reducing sugars (6.22-56.19%), total sugars (55.30-96.30%), and carotenoids (0.21-1.27 mg.100 g-1) varied. The indicated shelf life was approximately 117 and 65 days for jams in polypropylene package, and 112 and 63 days for those kept in the polyethylene package, when the temperature of storage was 25 and 35 ºC, respectively. Araticum fruit is a good source for jams, that can contribute to the increased insertion of foods of better nutritional value in the consumer market.

Detection of SARS-CoV-2 virus via dynamic light scattering using antibody-gold nanoparticle bioconjugates against viral spike protein.

Mass testing for the diagnosis of COVID-19 has been hampered in many countries owing to the high cost of genetic material detection. This study reports on a low-cost immunoassay for detecting SARS-CoV-2 within 30 min using dynamic light scattering (DLS). The immunosensor comprises 50-nm gold nanoparticles (AuNPs) functionalized with antibodies against SARS-CoV-2 spike glycoprotein, whose bioconjugation was confirmed using transmission electron microscopy (TEM), UV-Vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), and surface-enhanced Raman scattering spectroscopy (SERS). The specific binding of the bioconjugates to the spike protein led to an increase in bioconjugate size, with a limit of detection (LOD) 5.29 × 103 TCID50/mL (Tissue Culture Infectious Dose). The immunosensor was also proven to be selective upon interaction with influenza viruses once no increase in size was observed after DLS measurement. The strategy proposed here aimed to use antibodies conjugated to AuNPs as a generic platform that can be extended to other detection principles, enabling technologies for low-cost mass testing for COVID-19.