Encapsulation and controlled release of bioactive compounds in lactoferrin-glycomacropeptide nanohydrogels : curcumin and caffeine as model compounds

Curcumin and caffeine (used as lipophilic and hydrophilic model compounds, respectively) were successfully encapsulated in lactoferrin-glycomacropeptide (Lf-GMP) nanohydrogels by thermal gelation showing high encapsulation efficiencies (>90 %). FTIR spectroscopy confirmed the encapsulation of bioactive compounds in Lf-GMP nanohydrogels and revealed that according to the encapsulated compound different interactions occur with the nanohydrogel matrix. The successful encapsulation of bioactive compounds in Lf-GMP nanohydrogels was also confirmed by fluorescence measurements and confocal laser scanning microscopy. TEM images showed that loaded nanohydrogels maintain their spherical shape with sizes of 112 and 126 nm for curcumin and caffeine encapsulated in Lf-GMP nanohydrogels, respectively; in both cases a polydispersity of 0.2 was obtained. The release mechanisms of bioactive compounds through Lf-GMP nanohydrogels were evaluated at pH 2 and pH 7, by fitting the Linear Superimposition Model to the experimental data. The bioactive compounds release was found to be pH-dependent: at pH 2, relaxation is the governing phenomenon for curcumin and caffeine compounds and at pH 7 Ficks diffusion is the main mechanism of caffeine release while curcumin was not released through Lf-GMP nanohydrogels.

Advances in preservation of fruits and vegetables with bioactive coatings

Bioactive compounds are a large group of compounds (antimicrobials, antioxidants, nutrients, etc.), but its use in edible fi lms and coatings for application on fruits and vegetables has been very important because nowadays the consumers demand fruits and vegetables that are fresh, healthy, high quality and easy to prepare. A number of investigations have shown that the use of additives in edible fi lms and coatings improve its functionability and provide compounds for human health. However, it is necessary to continue research that can generate specifi c or tailor-made edible fi lms and coatings for each product with the best characteristics for preservation. In this review we present and analyze the concepts, progress and perspectives in the design and application of edible fi lms and coatings for fruits and vegetables in order to defi ne the challenges and opportunities that this topic of study in the fi eld of science, technology and food engineering.

Avaliação de uma proposta contextualizada sobre o ensino de polarimetria nos cursos de farmácia e engenharia de alimentos, na Universidade Federal do Ceará

This work deals with an evaluation of an experimental application about polarimetry for pharmacy and food engineering courses. Foods obtained from the undergraduate students were used for demonstrating multidisciplinary concepts and these concepts were associated to the teaching of polarimetry. According to the results, the benefits of the contextualization are beyond the class and the undergraduating students became interested in control of quality of foods. From these results, it can be concluded that the experimental emphasis given is valid and creates motivation and interest for learning physico-chemistry, in comparison with the traditional methodology applied to teach polarimetry.

El Outsourcing en la dinámica de sistemas hacia mercados extranjeros

Este trabajo recopila literatura académica relevante sobre estrategias de entrada y metodologías para la toma de decisión sobre la contratación de servicios de Outsourcing para el caso de empresas que planean expandirse hacia mercados extranjeros. La manera en que una empresa planifica su entrada a un mercado extranjero, y realiza la consideración y evaluación de información relevante y el diseño de la estrategia, determina el éxito o no de la misma. De otro lado, las metodologías consideradas se concentran en el nivel estratégico de la pirámide organizacional. Se parte de métodos simples para llegar a aquellos basados en la Teoría de Decisión Multicriterio, tanto individuales como híbridos. Finalmente, se presenta la Dinámica de Sistemas como herramienta valiosa en el proceso, por cuanto puede combinarse con métodos multicriterio.

Determinação da Lipoperoxidação em óleo alimentar

O ensaio realizado visa a determinação do índice de peróxidos (IP) em amostras de óleo alimentar refinado através do aquecimento das amostras durante 10, 20, 60 minutos. Com os sucessivos aquecimentos é possível avaliar o grau de degradação do produto alimentar pela formação de substâncias oxidantes esperando-se que, consoante o tempo de aquecimento, ocorra um aumento IP. Uma exposição contínua aos radicais livres poderá desencadear alterações a longo prazo no organismo do consumidor.

Optimisation of high temperature puffing of potato cubes using response surface methodology

One cubic centimetre potato cubes were blanched, sulfited, dried initially for between 40 and 80 min in air at 90 degreesC in a cabinet drier, puffed in a high temperature fluidised bed and then dried for up to 180 min in a cabinet drier. The final moisture content was 0.05 dwb. The resulting product was optimised using response surface methodology, in terms of volume and colour (L-*, a(*) and b(*) values) of the dry product, as well as rehydration ratio and texture of the rehydrated product. The operating conditions resulting in the optimised product were found to be blanching for 6 min in water at 100 degreesC, dipping in 400 ppm sodium metabisulfite solution for 10 min, initially drying for 40 min and puffing in air at 200 degreesC for 40 s, followed by final drying to a moisture content of 0.05 dwb. (C) 2003 Elsevier Ltd. All rights reserved.

Recovery of gallic acid with colloidal gas aphrons (CGA)

In the present paper the potential application of colloidal gas aphrons (CGA) to the recovery of antioxidants from wine-making waste extracts is investigated. CGA were generated by stirring a buffered solution (400 ml) of a cationic surfactant(cetyltrimethylammonium bromide, CTAB) at 8000 rpm for 10 minutes. Trials were carried out on standard solutions (2 ml) of gallic acid (GA) 200 mg/l with varying volumes of colloidal gas aphrons (20-60 ml) generated with varying concentrations of CTAB (2 and 4 mM). Influence of pH, solvent (buffered aqueous solution and ethanol), CTAB to GA molar ratio on recovery were studied. Best recovery (63%) was achieved from an aqueous solution of GA and at a CTAB to GA molar ratio of 16. Separation is mainly driven by electrostatic interactions but pH conditions are to be optimised to preserve the GA antioxidant power.

Transient development of whipped cream properties

Commercially available UHT cream was tempered at 4 degrees C for 24 h and whipped for different times: 3. 6. 9 and 12 nun. The following properties of cream were measured: rheological and interfacial properties. overrun and size distribution of air bubbles. The whipping process changes the properties of cream, which exhibits viscoelastic behaviour with a high influence of elastic component. The air bubbles incorporated during the process result in forming stronger foam containing smaller bubbles. and also give a higher overrun. These changes are observed around 9 min of whipping. when the amount of air is sufficient to create a stable structure. Further whipping reduces the overrun and the foam partly collapses: this may be caused by aggregation of fat droplets. (c) 2005 Elsevier Ltd. All rights reserved.

Kinetics of high pressure facilitated starch gelatinisation in Thai glutinous rice

The combined effect of pressure and temperature on the rate of gelatinisation of starch present in Thai glutinous rice was investigated. Pressure was found to initiate gelatinisation when its value exceeded 200 MPa at ambient temperature. On the other hand, complete gelatinisation was observed at 500 and 600 MPa at 70 degrees C, when the rice was soaked in water under these conditions for 120 min. A first-order kinetic model describing the rate of gelatinisation was developed to estimate the values of the rate constants as a function of pressure and temperature in the range: 0.1-600 MPa and 20-70 degrees C. The model, based on the well-known Arrhenius and Eyring equations, assumed the form [GRAPHICS] The constants k(0), E-a, and Delta V were found to take values: 31.19 s(-1), 37.89 kJ mol(-1) and -9.98 cm(3) mol(-1), respectively. It was further noted that the extent of gelatinisation occurring at any time, temperature and pressure, could be exclusively correlated with the grain moisture content. (c) 2006 Elsevier Ltd. All rights reserved.

High pressure induced water uptake characteristics of Thai glutinous rice

Glutinous rice (or sticky rice) has to be soaked in water over an extended period of time before cooking. Soaking provides some of the water needed for starch gelatinisation to occur during cooking. The extent of water uptake during soaking is known to be influenced by temperature. This paper explores the use of very high pressures up to 600 MPa to accelerate water uptake kinetics during soaking. Changes occurring in length, diameter and moisture content were determined as a function of soaking time, pressure and temperature. The results show that length and diameter are positively correlated with all three parameters. However, the expansion ratios are not very high: the maximum length expansion ratio observed was 1.2, while the maximum diameter expansion ratio was 1. 1. Given these low values, it was possible to model water uptake kinetics by using the well-known Fickian model applied to a finite cylinder, assuming uniform average dimensions and effective diffusion coefficient. The results showed that the overall rates of water uptake and the equilibrium moisture content increased with pressure and temperature. The effective diffusion coefficient, on the other hand, did not follow the same trend. Temperature influenced the effective diffusion coefficient below 300 MPa, but had a marginal effect at higher pressures. Moreover, the effective diffusion coefficient increased with temperature between 20 and 50 degrees C, but dropped at higher temperatures. This drop can be attributed to the gelatinisation of starch, which restricts the transport of water. Regardless, it is possible to increase the quantity of water absorbed by rice and the rate at which it is absorbed, by using high pressures and temperatures. (c) 2004 Elsevier Ltd. All rights reserved.

Dielectric properties of process cheese from 0.3 to 3 Ghz

Dielectric properties of 16 process cheeses were determined over the frequency range 0.3-3 GHz. The effect of temperature on the dielectric properties of process cheeses were investigated at temperature intervals of 10 degrees C between 5 and 85 degrees C. Results showed that the dielectric constant decreased gradually as frequency increased, for all cheeses. The dielectric loss factor (epsilon") decreased from above 125 to below 12 as frequency increased. epsilon' was highest at 5 degrees C and generally decreased up to a temperature between 55 and 75 degrees C. epsilon" generally increased with increasing temperature for high and medium moisture/fat ratio cheeses. epsilon" decreased with temperature between 5 and 55 degrees C and then increased, for low moisture/fat ratio cheese. Partial least square regression models indicated that epsilon' and epsilon" could be used as a quality control screening application to measure moisture content and inorganic salt content of process cheese, respectively. (c) 2005 Elsevier Ltd. All rights reserved..

Prediction of processed cheese instrumental texture and meltability by mid-infrared spectroscopy coupled with chemometric tools

The objective of this study was to determine the potential of mid-infrared spectroscopy coupled with multidimensional statistical analysis for the prediction of processed cheese instrumental texture and meltability attributes. Processed cheeses (n = 32) of varying composition were manufactured in a pilot plant. Following two and four weeks storage at 4 degrees C samples were analysed using texture profile analysis, two meltability tests (computer vision, Olson and Price) and mid-infrared spectroscopy (4000-640 cm(-1)). Partial least squares regression was used to develop predictive models for all measured attributes. Five attributes were successfully modelled with varying degrees of accuracy. The computer vision meltability model allowed for discrimination between high and low melt values (R-2 = 0.64). The hardness and springiness models gave approximate quantitative results (R-2 = 0.77) and the cohesiveness (R-2 = 0.81) and Olson and Price meltability (R-2 = 0.88) models gave good prediction results. (c) 2006 Elsevier Ltd. All rights reserved..

Development of a light scatter sensor technology for on-line monitoring of milk coagulation and whey separation

The objective of this study was to investigate a novel light backscatter sensor, with a large field of view relative to curd size, for continuous on-line monitoring of coagulation and syneresis to improve curd moisture content control. A three-level, central composite design was employed to study the effects of temperature, cutting time, and CaCl2 addition on cheese making parameters. The sensor signal was recorded and analyzed. The light backscatter ratio followed a sigmoid increase during coagulation and decreased asymptotically after gel cutting. Curd yield and curd moisture content were predicted from the time to the maximum slope of the first derivative of the light backscatter ratio during coagulation and the decrease in the sensor response during syneresis. Whey fat was affected by coagulation kinetics and cutting time, suggesting curd rheological properties at cutting are dominant factors determining fat losses. The proposed technology shows potential for on-line monitoring of coagulation and syneresis. 2007 Elsevier Ltd. All rights reserved..