Effects of cactus pear clone harvest seasons and times on the physicochemical and technological properties of resulting mucilage and biopolymeric films.

Cactus pear cladodes, clones 'Miúda' (MIU) and 'Orelha de Elefante Mexicana' (OEM) were harvested at 6 am and 8 pm during the rainy-dry, dry and rainy seasons to evaluate the effect of type of clone and harvest seasons on the physicochemical and technological properties of mucilage as well as the optical, physicochemical, mechanical, thermal and microstructural characteristics of the films obtained. The mucilage of the OEM clone presented a higher content of phenolic compounds, compared to the Nopalea genus, regardless of the season and time of harvest. Furthermore, the dry period resulted in higher carbohydrate levels, regardless of the harvest time. The biopolymeric films produced from the OEM clone harvested in the rainy season and rainy-dry transition showed darker color, better mechanical properties, water barrier, compact microstructure and thermal stability when compared to the MIU clone. Furthermore, harvesting at 6 am provided improvements in the mechanical conditions, permeability and thermal stability of the films of both types of clones studied. These results showed strong environmental modulation, naturally incorporating important macromolecules such as carbohydrates and phenolic compounds, used in the industry in the production of nutraceutical foods, into the mucilage. Furthermore, harvesting cladodes at 6 am in the rainy and transitional (rainy-dry) periods provided better quality biopolymeric films and/or coatings.

Physiological Responses of Minimally Processed Sweet Potatoes Grown with Increasing Doses of Phosphate Fertilizer.

The present work aimed to study oxidative damage and protection, phenylpropanoid metabolism, and the quality of minimally processed colored sweet potatoes cultivated with increments in P2O5 fertilization. Sweet potato was cultivated with 0, 60, 120, 180, and 240 kg ha-1 of P2O5. The roots were harvested, and the P content in the roots and leaves was quantified. The roots were minimally processed and kept for 20 days at 5 °C. In general, the roots that were fertilized with P2O5 showed a higher content of the analyzed variables. The highest P dosage in the soil increased the P content in roots and leaves and the agro-industrial yield. Roots cultivated with P2O5 showed a higher content of hydrogen peroxide, phenolic compounds, vitamin C, yellow flavonoids, anthocyanins, and carotenoids, antioxidant capacity by the DPPH method, and higher activity of the enzymes polyphenol oxidase, peroxidase, and phenylalanine ammonia lyase. These results demonstrated the role of phosphorus in protecting against oxidative damage due to the accumulation of bioactive compounds, thus improving the physicochemical quality of minimally processed orange sweet potato.