Functional foods enriched in Aloe vera. Effects of vacuum impregnation and temperature on the respiration rate and the respiratory quotient of some vegetables

Abstract

This work is part of a study on the process of production of vegetables enriched in Aloe vera using the vacuum impregnation (VI) technique. The objectives of this work were: (i) to analyze the effects of VI with Aloe vera on some quality parameters of vegetables: water activity, water content, soluble solids content, real and apparent densities, and pH; (ii) to analyze the effects of the presence of Aloe vera in VI solutions and temperature on the respiration rates (carbon dioxide production and oxygen consumption) and the respiration quotient of some vegetables (endive, cauliflower, broccoli and carrots). VI made it possible to incorporate up to 7g of Aloe vera in 100g (dry matter) of broccoli, about 4g in cauliflower and endive, and about 3g in carrot. In almost all cases, respiration rate values were higher at 20°C than at 5°C. For vegetables submitted to VI using an isotonic sucrose solution, and in comparison with fresh samples, respiration rates at 5°C were higher for broccoli, endive and carrot, but lower for cauliflower. At 20°C, they were higher in the case of broccoli, endive and cauliflower, but lower for carrots. As compared with fresh samples, and at 5°C, respiration rates were lower for all vegetables impregnated using a solution with 30g/L of Aloe vera powder; at 20°C, they were lower for cauliflower, but higher for broccoli, endive and carrots. The presence of Aloe vera in sufficient concentration seemed to compensate the metabolic stress caused by the application of vacuum.