Evaluación de la funcionalidad tecnológica y nutricional del zumo de lima (Citrus latifolia tanaka) encapsulado en pulverizado de mesocarpo de pomelos (Citrus paradisi macf)

Abstract

The juice of Persian lime (Citrus latifolia Tanaka) is attributed nutritional, healing and medicinal properties given its functional characteristics, which can be preserved by spray drying; however, this method presents challenges such as: type and concentration of coating material, process operations, packaging material and storage conditions. On the other hand, the grapefruit mesocarp (Citrus paradisi Macf), is a nutritive industrial waste that after being dehydrated could become an encapsulating agent. Looking to take advantage of this by-product, add value and enable its industrialization, preserve the juice properties to the maximum and mitigate the challenges of spray drying, in this research five studies were carried out. The objective of the first study was to obtain and characterize an encapsulant from the grapefruit mesocarp. Two dehydration methods (trays dehydrator and microwave oven) and two thicknesses of mesocarp sheet (2 and 4 mm) were evaluated on yield, dehydration and physicochemical characteristics; determining that: the sheet thickness affects the performance, dehydration and viscosity of the encapsulant; the dehydration method and the interaction of the factors affected the pH, viscosity, bulk density, gelatinization temperature, water absorption index and swelling power. The purpose of the second study was to evaluate five concentrations of grapefruit encapsulant: 0.4; 0.8; 1.2; 1.6 and 2.0% (w/w), and a control: maltodextrin 10 DE (1.2%, w/w), on the yield and bromatological characteristics of the atomized Persian lime juice: pH, water activity (aw), titratable acidity (AT), soluble solids (SS), humidity, ash, carbohydrates, proteins, total phenolic compounds (CFT), total flavonoids (FT), ascorbic acid (AA), differences in taste, color and smell, glass transition temperature (Tg) and particle morphology. It was observed that the concentrations of encapsulants affect the physicochemical, organoleptic and nutritional characteristics evaluated, with the exception of proteins; the bioactive components were lower in the control, and the highest yield was obtained with 1.2% grapefruit mesocarp; the amount of encapsulant did not modify the Tg of the powders, presenting particles of different sizes and shapes. In the third study was evaluated the effect of the inlet temperature (125, 135 and 145 °C), spray pressure (4.00; 4.21 y 4.42 kg/cm2) and feeding (0.80; 0.85 y 0.90 L/h) on the yield, pH, aw, SS, humidity, proteins, ashes, carbohydrates, AA, CFT, FT, Tg, color differences, odor and taste and the morphology of the particles of powder Persian lime juice. The inlet temperature does not affect the SS, humidity or ash. The feeding does not influence the SS, proteins, ashes or Tg, and the atomization affected all the response variables; the encapsulated juices showed varied and irregular shapes and structures, with differences in taste, color and smell. In the fourth study the stability of the Persian lime juices encapsulated in grapefruit mesocarp pulverized was evaluated, during 4 months of storage at different temperatures (25 °C, 30 °C and room), in terms of: pH, aw, carbohydrates, AA, CFT and FT. The pH and aw of the sprayed juices increased with time. Carbohydrates, AA, CFT and FT showed unstable behavior, being the most pronounced losses during storage at room temperature and 30 °C. The purpose of the fifth study was to evaluate the effect of five concentrations of Persian lime juice encapsulated in pulverized grapefruit mesocarp (0.01, 0.02, 0.03, 0.04 and 0.05%), on the pH, aw, SS, humidity and parameters of color of a papaya nectar, using as a control 0.03% of citric acid. The inclusion of atomized lime juice affects pH, a* and Hue.