Erick Scheuermann

Effect of immersion solutions on shelf-life of minimally processed lettuce

Abstract Prior to detailed quality and physiology evaluations, different immersion solutions (SIs) were analysed by means of a nontrained sensory panel. Each SI (calcium chloride, pectin, potassium sorbate, garlic extract and citric acid) was analysed at three concentrations. Based on at least 70% acceptance, the best mixed SI ( P

Comparative study of different process conditions of freeze drying of 'Murtilla' berry

Different operating conditions for drying halves of ‘Murtilla’, a native Chilean berry food species, were studied in atmospheric freeze drying, using dry air through a pulsed fluidized bed, and vacuum freeze drying. Applying a 23 experimental design, the effect of the freezing rate, the air temperature, and the application of infrared radiation was studied on the moisture content and the drying time. Fast freezing with infrared (IR) and air at 15°C for the second drying stage allowed achieving final moisture contents similar to vacuum freeze drying in equivalent total drying periods. Drying at the same conditions except with air at 5°C resulted in a larger preservation of antioxidant capacity of the fresh fruit. Also, the texture was adequate for a dry fruit, with a pleasant flavor for direct consumption or mixed with yogurt. The drying kinetics of the first drying stage was modeled by an equation based on the uniformly retreating ice front model, which gave a reasonable description of the trend for this stage, although it does not include the application of IR radiations or the rate of freezing. The Page equation was an adequate tool to represent the second drying stage (which started after 7 h) for each experimental run, by using specific parameters (n and k) obtained by fitting the experimental data. The parameters exhibited similar values to those cited in the literature for foods.

Influence of genotype and harvest year on polyphenol content and antioxidant activity in murtilla (Ugni molinae Turcz) fruit

Polyphenol content and antioxidant activity in murtilla (Ugni molinae Turcz) fruit from three genotypes (the 14-4 genotype and the Red Pearl-INIA and South Pearl-INIA varieties) were studied over five growing seasons. Our results showed significant differences in total polyphenol content among yearly harvests. The lowest value (283 ± 72 mg GAE/100 g dw) was obtained for the 14-4 genotype in the 2008 harvest, and the highest value (2,152 ± 290 mg GAE/100 g dw) was observed for the variety South Pearl-INIA in 2007. The lowest value for antioxidant activity (2,234 ± 337 μmol TE/100 g dw) was obtained for the Red Pearl-INIA variety in 2008, and the highest value (4,073 ± 76 μmol TE/100 g dw) was observed for the 14-4 genotype in 2007. There was a significant effect of genotype and growing season on polyphenol content, antioxidant activity and dry matter content for the murtilla fruits evaluated in this study, but additional studies examining other abiotic and biotic factors are required to fully explain causality.

Effect of operating conditions in freeze-drying on the nutritional properties of blueberries

The effect of particle size, use of infrared radiation, and type of freeze-drying (vacuum or atmospheric) on some nutritional properties of blueberries was investigated. Ascorbic acid was decreased in freeze-dried blueberries compared with fresh fruit, while polyphenols were decreased in atmospheric freeze-drying—unlike in vacuum freeze-drying, where this nutritional property was increased. Antioxidant activity of freeze-dried blueberries did not differ significantly from that found in fresh fruits. In order to minimize the impairment of the nutritional properties of freeze-dried blueberries, it is suggested to use infrared radiation, a relatively small particle size and vacuum freeze-drying.

Antioxidant and Vasodilator Activity of Ugni molinae Turcz. (Murtilla) and Its Modulatory Mechanism in Hypotensive Response

Hypertension is a systemic condition with high morbidity and mortality rates worldwide, which poses an increased risk for cardiovascular diseases. In this study, we demonstrated the antioxidant and vasodilator activity of Ugni molinae Turcz. (Murtilla) fruit, a berry native to Chile and proposed models to explain its modulatory mechanism in hypotensive response. Murtilla fruits were cultivated in a germplasm bank and submitted to chemical and biological analyses. The phenolic compounds gallic acid, Catechin, Quercetin-3-β-D-glucoside, Myricetin, Quercetin, and Kaempferol were identified. Murtilla extract did not generate toxic effects on human endothelial cells and had significant antioxidant activity against ROS production, lipid peroxidation, and superoxide anion production. Furthermore, it showed dose-dependent vasodilator activity in aortic rings in the presence of endothelium, whose hypotensive mechanism is partially mediated by nitric oxide synthase/guanylate cyclase and large-conductance calcium-dependent potassium channels. Murtilla fruits might potentially have beneficial effects on the management of cardiovascular diseases.