Josiane Kuhn Rutz

Microencapsulation of palm oil by complex coacervation for application in food systems

This study aimed at microencapsulating palm oil, containing high carotenoid content, with chitosan/xanthan and chitosan/pectin, using the complex coacervation method, followed by atomization and lyophilization. The DSC technique was used to confirm the encapsulation. The atomized microparticles had spherical shape and irregular size, and the lyophilized microparticles had irregular shape and size. Lyophilization resulted in lower carotenoids losses, and higher yield and encapsulation efficiency. In addition, the release profile in both water and gastrointestinal fluid was satisfactory. Prior to their application in food, a greater percentage of carotenoids was released in the fluid that simulates gastrointestinal conditions; however, the compounds were degraded after their release. In this case, the chitosan/pectin microparticles showed the best release profile. After processing, the release was lower and the released compounds were not degraded. Thus, the chitosan/xanthan microparticles showed the best potential for practical application, particularly, in yogurt preparation.

Elaboration of microparticles of carotenoids from natural and synthetic sources for applications in food

Carotenoids are susceptible to isomerization and oxidation upon exposure to oxygen, light and heat, which can result in loss of color, antioxidant activity, and vitamin activity. Microencapsulation helps retain carotenoid stability and promotes their release under specific conditions. Thus, the aim of the study was to encapsulate palm oil and β-carotene with chitosan/sodium tripolyphosphate or chitosan/carboxymethylcellulose and to assess the performance of these microparticles in food systems by analyzing their release profile under simulated gastric and intestinal conditions. Encapsulation efficiency was greater than 95%, and the yield of microparticles coated with chitosan/sodium tripolyphosphate was approximately 55%, while that of microparticles coated with chitosan/carboxymethylcellulose was 87%. Particles encapsulated with chitosan/carboxymethylcellulose exhibited ideal release behavior in water and gastric fluid, but showed low release in the intestinal fluid. However, when applied to food systems these particles showed enhanced carotenoid release but showed low release of carotenoids upon storage.

Stabilization of guava nectar with hydrocolloids and pectinases

The aim of this study was to stabilize guava nectar using hydrocolloids and/or enzymes, and evaluate the stability and the bioactive compounds content during storage. In general, there was a decrease in pH and an increase in titratable acidity and soluble solids of the nectars. During storage, it was observed that nectars with pectinase showed decrease in pH, increase in titratable acidity and soluble solids, and also less phase separation, standing out among them the nectar with enzyme and guar gum. The nectar formulated with xanthan showed the highest antioxidant capacity. All nectars showed slight decrease in the carotenoid content and high losses of vitamin C during the storage period.

Conservation of minimally processed apples using edible coatings made of turnip extract and xanthan gum

The objective of this study was to evaluate the potential of turnip extract and xanthan gum in the conservation of minimally processed apples. The apples were washed, sanitized with sodium hypochlorite (200 ppm) for 15 minutes, peeled, and cut into eight pieces prior to being subjected to one of the following treatments in aqueous solution: A – water (control); B – turnip extract; C – turnip extract and CaCl2; D – xanthan gum, CaCl2 and glycerol; E – turnip extract, xanthan gum, CaCl2, and glycerol. Subsequently, the freshly cut apples were dried under ventilation on nylon screens to ensure drying of the coatings, and then packed in polystyrene trays, covered with polyvinylchloride films and stored at 4 ± 1 ° C for 13 days. The following parameters were evaluated: mass loss, firmness, colouration, pH value, soluble solids, and peroxidase/polyphenoloxidase activities. The edible coatings were found to be ineffective with respect to controlling mass loss, but the minimally processed apples coated with turnip extract maintained their initial levels of colouration, firmness and pH value. A considerable increase in peroxidase activity was registered for apples treated with turnip extract, suggesting that this effect may also be responsible for the reduction in browning. No advantage could be observed for the simultaneous presence of turnip extract and xanthan gum or calcium chloride. The turnip extract may represent an interesting alternative for applications to minimally processed apples, especially as it is a natural product, easily obtained, cost effective and contributes to the nutritional quality (e.g. as a source of calcium ions).