Search

This research evaluated the influence of natural emulsifier on the emulsion particle size of the black pepper oleoresin combined with a sucrose solution, and its effects on the kinetics of chayote osmodehydration and the extent of piperine fortification. Macroemulsions with gum arabic (GA) and nanoemulsions with whey protein concentrate (WPC) were prepared in a 50% sucrose solution. The mean particle size and polydispersity index of both sucrose-emulsion solutions were determined using dynamic light scattering, and the kinetics of water loss (W F L), solids gain (S G), water activity (a w), and water diffusion coefficients (D w) were obtained during the osmotic processing (25–45 °C). With a particle size of 165 nm, the WPC nanoemulsion had a higher viscosity than the GA emulsion, which measured 655 nm making them susceptible to coalescence. Scanning electron micrographs revealed that during osmotic dehydration, the WPC nanoemulsions formed dense layers within the chayote tissue. This resulted in reduced water loss kinetics and diffusivity, particularly at high temperatures. In terms of fortifying chayote with piperine, the use of a macroemulsion resulted in greater rates of impregnation (0.12 mg piperine (g wet solids min)−1) compared to the nanoemulsion, which had rates of 0.04 mg piperine (g wet solids min)−1. After 420 min of osmodehydration, it was observed that the GA macroemulsion resulted in higher levels of piperine impregnation than the WPC nanoemulsion. These findings have important implications for successfully fortifying fruits and vegetables with lipophilic bioactive compounds using emulsions in combination with the osmotic dehydration technique. [Display omitted] • Chayote was fortified with piperine through emulsions and osmotic dehydration. • The size of the emulsion influences the osmotic dehydration kinetics of chayote. • The size of the emulsion affects the viscosity of the osmotic solution. • The high viscosity of the osmotic medium decreases the diffusivity of water. • Fortification of chayote with piperine was achieved using a macroemulsion. [ABSTRACT FROM AUTHOR]

Plantar fasciitis is the most common cause of heel pain. It accounts for 80% of the cases and has an estimated prevalence rate of up to 7% in the general population, with bilateral involvement in 20% to 30% of those patients. This condition affects people of working age, thereby limiting and diminishing their quality of life. There are a wide range of treatment options for the management of plantar fasciitis that include both conservative and surgical treatments. Although surgical treatment based on partial or total plantar fascia release has success rates of some 70% to 90%, it is not free of complications. These complications, soft-tissue healing problems, superficial infection, or longitudinal arch collapse in cases of a greater than 40% release of the fascia. Bipolar radiofrequency appears to be a safe procedure for refractory plantar fasciitis that can provide outcomes equivalent to open plantar fascia release with less morbidity. The purpose of this article is to describe the local percutaneous radiofrequency technique for patients with chronic, recalcitrant plantar fasciitis. [Display omitted] [ABSTRACT FROM AUTHOR]

Bilateral teleoperators are widely used in several applications such as surgical robots and underwater vehicles. However, due to the long distance between the local and remote manipulators, time delay arises over the communication channel, so that neither exact tracking position nor perfect transparency can be achieved. In free movement, most control approaches are meant to guarantee consensus or to synchronize the local and the remote robots by inducing periodic position trajectories. In constrained motion, the human operator can only have some telepresence feeling but not perfect transparency. Furthermore, most algorithms are designed assuming that joint velocities are available, while sometimes this is not the case and it is desirable to estimate joint velocities through an observer. In this work, a novel teleoperation controller–observer scheme is introduced that does not make use of velocity measurements and, more importantly, does not require the exact knowledge of the dynamical model. This scheme has the following properties: (a) in free motion and without a human operator, the local and the remote manipulators tend either to a periodic trajectory or to a particular position, thus achieving either synchronization or position consensus; (b) when a human operator moves the local robot, the remote manipulator tracks the commanded position with the corresponding delay; (c) in constrained motion, the human operator has some feeling of telepresence. Experimental results are provided to validate the proposed algorithm. [ABSTRACT FROM AUTHOR]

Black pepper oleoresin was encapsulated by spray drying using gum arabic (GA) and whey protein concentrate (WPC) as wall materials. The physical surface features were examined using low-temperature adsorption of nitrogen at 77 K. Clustering function and spreading pressure were evaluated to predict optimal storage conditions of the microcapsules, through analyzing the data from the water adsorption isotherms determined using a gravimetric method at 25, 35, and 45 °C. Kinetic studies of the color changes and loss of piperine of the microcapsules stored at different water activities at 35 °C were carried out. It was found that the GAB, BET and Condon models adequately describe the sorption characteristics. The monolayers calculated with the clustering function and minimum change in spreading pressure (MCSP) were close to those obtained by the adsorption models. The isotherms local from the Condon model coincided with the levels of stability of the microcapsules. Two local isotherms were found for GA microcapsules, which exhibited two regions of chemical stability during storage. One region with high stability in the range of 0.108–0.515 a w , and the other with poor stability of 0.515–0.821 a w. Conversely, WPC microcapsules showed one isotherm local, which had high stability in the entire water activity range studied. For both microcapsules, the lowest values of color changes were of 1.5–4, while the degradation rate constants were −0.017 day−1 and -0.002 day−1 for GA and WPC, respectively. The water activities where occurred the optimal stability fall within of the MCSP zone. • The spray drying process can encapsulate black pepper oleoresin using biopolymers. • Wall material influences the stability of encapsulated black pepper oleoresin. • The clustering function permits calculating the monolayer from the water isotherm. • Minimum spreading pressure shows the optimum storage conditions for dehydrated food. • The chi plot of the water adsorption identifies possible levels of food stability. [ABSTRACT FROM AUTHOR]