In vivo Cellular Uptake,Degradation, and Biocompatibility of Polyelectrolyte Microcapsules

Polyelectrolyte microcapsules are made by layer‐by‐layer (LbL) coating of a sacrificial template, followed by decomposition of the template, to produce hollow microcapsules. In this paper, we report on the in vivo cellular uptake, degradation and biocompatibility of polyelectrolyte microcapsules produced from alternating dextran sulphate and poly‐L‐arginine layers on a template of calcium carbonate microparticles. We show that a moderate tissue reaction is observed after subcutaneous injection of polyelectrolyte microcapsules in mice. Within sixteen days after subcutaneous injection, most of the microcapsules are internalized by the cells and start to get degraded. The number of polyelectrolyte layers determines the stability of the microcapsules after cellular uptake.     

Chemical analysis of French beans (Phaseolus vulgaris L.) by headspace solid phase microextraction (HS-SPME) and simultaneous distillation/extraction (SDE)

Headspace Solid Phase Microextraction (HS-SPME) involving divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fibre and simultaneous distillation/extraction (SDE) techniques were applied to study the volatile and semi volatile compounds of thawed and cooked Phaseolus vulgaris L. A total of 104 compounds were detected by GC and GC/MS. Thereof, 76 compounds were identified for the first time in this species. The major differences between HS-SPME and SDE were found in the content of identified alcohols (23.62% SDE versus 62.20% SPME), terpenoids (39.15% SDE versus 2.45% SPME), heterocyclic compounds (13.78% SDE versus 1.21% SPME), hydrocarbons (2.22% SDE versus 13.87% SPME) and esters (0.98% SDE versus 12.98% SPME). The SPME technique was found to be useful for rapid and routine quality controls of thawed French beans, while SDE is favourable to study the entire set of flavour volatiles in the corresponding cooked samples.     

Phenolic compounds and plant extracts protect paprika against UV-induced discoloration

The efficiency of phenolic antioxidants in protecting paprika carotenoids against discoloration was studied in a model gel system that was exposed to radiation of 274 nm at 20 °C. The fading of the colour of the gel was followed over a 6‐h period. Fifty percent of the colour faded from the control after 70 min of radiation. The ability of each antioxidant to prevent discoloration was assessed by using several different concentrations. Antioxidant compounds can be ranked according to their protective effect on colour: BHT > α‐tocopherol > epigallocatechin gallate > quercetin > rosmarinic acid ≥ caffeic acid and ferulic acid > coumaric acid > catechin. The ability of rosemary and tea extracts to prevent discoloration was comparable to pure compounds and this could be explained by their polyphenol content. Mixtures of α‐tocopherol with rosemary extract revealed strong synergistic effects.     

Baud rate timing recovery scheme for filter bank-based multicarrier transmission

This paper is devoted to the design and the steady-state performance analysis of a data-aided or decision-directed timing recovery scheme for filter bank-based multicarrier transmission with equalization. The symbol synchronizer is obtained from a Mueller and Muller approach extended to multiband transmission. A simple synchronizer is first proposed which can be derived from an approximate likelihood function. Then, possible improvements are discussed. Timing jitter variances are computed and discussed for high bit-rate transmission over copper wires.     

Confocal scanning laser microscopy and quantitative image analysis: application to cream cheese microstructure investigation

The naked eye observation of cream cheese confocal scanning laser microscopy images only provides qualitative information about its microstructure. Because those products are dense dairy gels, confocal scanning laser microscopy images of 2 different cream cheeses may appear close. Quantitative image analysis is then necessary to compensate for human eye deficiency (e.g., lack of precision, subjectivity). Two kinds of quantitative image analysis were performed in this study: high-order statistical methods and grayscale mathematical morphology. They were applied to study the microstructure of 3 different cream cheeses (same manufacturing process, same dry matter content, but different fat and protein contents). Advantages and drawbacks of both methods are reviewed. The way they may be used to describe cream cheese microstructure is also presented.     

Effect of dynamic heat treatment on the physical properties of whey protein foams

The influence of dynamically heat-induced aggregates on whey protein foams was investigated as a function of the thermal treatment applied with the aim of determining the optimal temperature for the production of heat-induced aggregates dedicated to foaming. The native protein solutions (2% w/v WPI; 50 mM NaCl) at neutral pH were heat-treated using a tubular heat exchanger between 70 °C and 100 °C. Protein denaturation and aggregation were followed by micro-differential scanning calorimetry, size exclusion chromatography, laser diffraction and dynamic light scattering. The protein solutions were whipped using a kitchen mixer to produce foams. Foam overrun, stability against drainage, texture and bubble size distribution were measured.     

Comparison of composition and quality traits of meat from young finishing bulls from Belgian Blue, Limousin and Aberdeen Angus breeds

Thirty-six young finishing bulls from three breeds (Belgian Blue, Limousin and Aberdeen Angus) were fattened over five months with finishing diets based either on sugar-beet pulp or on cereals. Nutritional quality traits of meat - fat content and fatty acid composition with emphasis on the n-6 and n-3 polyunsaturated fatty acids - along with some organoleptic quality traits were measured. The Belgian Blue bulls had the lowest intramuscular fat content associated with lower saturated and monounsaturated fatty acid contents. The polyunsaturated fatty acid content did not differ to a large extent between the breeds, the Aberdeen Angus bulls showing slightly higher values. Relative to energy intake, the overall contribution of meat to the n-3 fatty acid recommended intake was small, whatever the breed. By contrast, the contribution of meat to daily fat intake was of greater importance, especially for the Aberdeen Angus bulls. The quality traits of meat varied also according to the breed: compared to the Aberdeen Angus, the Belgian Blue bull meat had the stablest colour, the highest drip and the lowest cooking losses. The meat of Limousin bulls had intermediate characteristics for all the parameters.     

Strain-hardening properties of physical weak gels of biopolymers

Weak gels of biopolymers are frequently used in food applications. Dynamic rheological measurements, performed at low strain in the linear domain are useful to characterize the network properties, e.g. gelation, ageing and mechanical recovery after shearing. However, the rupture properties of these gels are also of great interest to complete their characterization.Several weak gels containing carrageenan, xanthan–locust bean gum, pectin or alginate–pectin were investigated. The behaviour of these gels under large strain was studied either in dynamic mode or under constant low shear rate conditions. In many cases, a strain-hardening behaviour was observed: above the upper limit of the linear domain, the stress increased more than proportionally to the strain. A good agreement in stress–strain variations was observed between the results from dynamic and constant shear rate modes.This hardening effect, generally associated with a large deformability, gave to these gels a large resistance to rupture, with regards to their modulus. This can be related to the functionality of the biopolymer systems in terms of texture or suspension properties. As an example, in fluid gels, it allows the suspension of particles with a very weak network (typically a modulus of 1 Pa).