Betalains of pitaya (Stenocereus pruinosus) fruit can be used as natural pigment, but they are susceptible to deterioration by temperature, pH, and presence of sugars. In this work, a refined extract (Er) of betalains was obtained through aqueous two-phase extraction, which reduced significantly sugar and mucilage contents. In order to favor stability, the encapsulation of the refined extract was evaluated, with native potato starch that was modified through phosphorylation or succinylation and reactive extrusion. Starches were evaluated in terms of degree of substitution, Fourier transform infrared spectroscopy, scanning electron microscopy, and viscous behavior. Microcapsules were formed by spray drying and their stability was evaluated at 40 °C for 39 days and by using them as pigmenting agent of yogurt at 4 °C during 32 days. The behavior of modified starches during encapsulation was superior to that of commercial N-Lok^® starch. Microcapsules based on modified starches showed better pigmenting potential and higher stability than Er and microcapsules based on N-Lok^® starch. The separation of betalains from pitaya fruit may be a good alternative for adding value to this plant genetic resource.

The objective of this study was to incorporate avocado peel (AEE) and coconut (CEE) extracts as antifungal additive in the development of gelatin and carboxymethylcellulose coatings to extend shelf life in strawberries. Fractions of 200 mg/L of extracts were incorporated in the coating and characterized during storage at 2°C. AEE and CEE in the coating delayed significantly (P < .05) weight loss (40%), softening, color, and compositional changes (°Brix, sugars, titratable acidity). Rhizopus stolonifer and Aspergillus niger strains were isolated and inoculated to evaluate the effectiveness of the coatings on strawberries. The use of the coating + plant extracts decreased the proliferation of fungi by 45% compared to the uncoated fruit and extended the shelf life for 15 days. With these findings, it is suggested that biopolymeric coatings + plant extracts can be used as a potential method of ecological preservation in strawberries against microbial deterioration.

Whey is a by-product of cheese manufacture and contains proteins that can be recovered, but lactose presence limits its use. Proteins can be separated with aqueous two-phase extraction (ATPE), thus the objective was to evaluate this strategy to recuperate proteins from whey attending lactose elimination. An ATPE system with (NH₄)₂SO₄ and polyethylene glycol 4000 (PEG4000) was studied at 25°C. As PEG4000 diminished the volume ratio between phases diminished and a biphasic system was maintained in absence of the polymer. Minimum protein recovering and lactose elimination were 54.5% and 62.1% with mixtures having 25% PEG4000 and 12.1% (NH₄)₂SO₄, but values were 93.0% and 72.3%, respectively, with 0.1% PEG4000 and 34.7% (NH₄)₂SO₄. Therefore, whey incorporated with (NH₄)₂SO₄ in concentration higher than 34% and without polyethylene glycol can be used in ATPE systems to maximize lactose elimination and protein recovering and to concentrate proteins up to 2.45 times through a non-energy strategy.