Effect of controlled atmospheres on the quality of white onion (Allium cepa L).

Onion is one of the oldest and most consumed crops in the world. Its quality deteriorates gradually during prolonged storage. In the present study, white onions of the variety "Sierra Blanca" were stored in a controlled atmosphere (CA) for 7 months. The color, total pungency, microbiological load and total carbohydrates were evaluated. Three treatments were applied: control treatment (CT), regular atmosphere at 2.5 °C without controlled relative humidity (RH); (T1)1% O2 + 1% CO2 at 2.5 °C and 60-75% RH and (T2)3% O2 + 5% CO2 at 2.5 °C and 60-75% RH. The statistical analysis showed a significant effect of the treatments and storage time in most of the variables analyzed. The CA managed to preserve the quality of the onion during the storage period while the control bulbs exhibited greater deterioration. These increased 2.9 times their level of pungency, had a higher microbial load and showed a very noticeable color change at the end of storage with respect to freshly harvested onions and those stored in a CA. They had a more yellow-green coloration. Both CA treatments were effective in preserving onion quality, but a more positive effect for T1 than T2 was observed on most of the parameters evaluated.

Characterization of the nutraceutical quality and antioxidant activity in bell pepper in response to grafting.

The grafting of fruits and vegetables influences fruit quality. The aim of the present work was to assess the effect of the rootstock and the scion on the antioxidant activity and the content in vitamin C, total phenols, lycopene and ß-carotene of bell pepper. The cultivars Fascinato and Jeanette were used as scion and Terrano was used as rootstock. Four harvests in the production cycle of the vegetable were analyzed in a cultivation system under shading nets. The results indicate statistical differences in the content of these bioactive compounds between the varieties, between grafting and not grafting and between sampling dates (p ≤ 0.05). The vitamin C content, ß-carotene, and antioxidant capacity proved significantly higher in Fascinato than in Janette. On average, grafting increased ß-carotene and vitamin C concentrations and improved the antioxidant capacity, but had no influence on the total phenol or lycopene contents. It is concluded that grafting to the rootstock Terrano improves the nutritional quality of the fruit produced in both varieties of bell pepper studied.