Modifications of biological membranes, fat globules and liposomes promoted by cavitation processes. Consequences and applications.

Cavitation-based technologies, such as ultrasound (or acoustic cavitation, AC) and hydrodynamic cavitation (HC), are gaining interest among green processing technologies due to their cost effectiveness in operation, toxic solvent use reduction, and ability to obtain superior processed products, compared to conventional methods. Both AC and HC generate bubbles, but their effects may differ and it is difficult to make comparisons as both are based on different phenomena and are subject to different operational variables. AC is one of the most used techniques in extraction and homogenization processes at the laboratory level.

Optimising the Polyphenolic Content and Antioxidant Activity of Green Rooibos () Using Beta-Cyclodextrin Assisted Extraction.

Antioxidant activity associated with green rooibos infusions is attributed to the activity of polyphenols, particularly aspalathin and nothofagin. This study aimed to optimise β-cyclodextrin (β-CD)-assisted extraction of crude green rooibos (CGRE) via total polyphenolic content (TPC) and antioxidant activity assays. Response surface methodology (RSM) permitted optimisation of β-CD concentration (0−15 mM), temperature (40−90 °C) and time (15−60 min).

The antioxidant and antiglycation activities of selected spices and other edible plant materials and their decay in sugar-protein systems under thermal stress.

Antiglycation activities of herbs and spices, have been described in relation to their in vivo anti-diabetic or anti-aging activity at physiological temperature. Under the hypothesis that those natural antioxidants may inhibit the formation of Maillard intermediates, the behavior of several hydroalcoholic plant extracts was analyzed in sugar-protein systems. Allspice, thyme, green pepper and black pepper extracts were the most efficient inhibitors, decreasing furosine formation by 60, 45, 40 and 30%, respectively.

Antioxidant and anti-glycation potential of green pepper (Piper nigrum): Optimization of β-cyclodextrin-based extraction by response surface methodology.

Green pepper (Piper nigrum) presents high levels of functional compounds, with antioxidant and anti-glycation properties. Thus, the optimization of the β-cyclodextrin-based extraction of functional compounds from green pepper through Response Surface Methodology was performed. The optimum extraction conditions were assessed by optimizing total polyphenolic content (TPC) and antioxidant activity (DPPH• and FRAP methods).

Non-enzymatic browning kinetics in sucrose-glycine aqueous and dehydrated model systems in presence of MgCl.

The development of non-enzymatic browning in the presence of MgCl was evaluated in liquid and dehydrated sucrose-glycine model systems, in relation to interactions of the salt with water and/or with sucrose. In both systems, browning was accelerated by the presence of MgCl because of the increased sugar hydrolysis (ten times faster) and the reduction of water mobility (H NMR T relaxation times) caused by this salt (between 6 and 14% lower), counteracting the inhibitory effect of water on the Maillard reaction. MgCl also provoked a 40% reduction on the fluorophores quantum yield, responsible also of the fluctuations observed in the fluorescence development as a function of time after 50 h at 70 °C.

Optimization of β-cyclodextrin-based extraction of antioxidant and anti-browning activities from thyme leaves by response surface methodology.

Thyme (Thymus vulgaris) has been demonstrated to extend the shelf-life of food products, being also a potential source of bioactive compounds. The aim of this research was to optimize the ultrasound assisted extraction employing β-cyclodextrin aqueous solutions as no-contaminant technology and Response Surface Methodology to obtain thyme extracts with the maximum antioxidant capacity. The optimal extraction conditions were: a solution of β-ciclodextrin 15 mM, an ultrasonic treatment time of 5.

Colour and surface fluorescence development and their relationship with Maillard reaction markers as influenced by structural changes during cornflakes production.

The aim of this work was to study colour and surface fluorescence development in relation to the chemical markers for the Maillard reaction at the cooking, flaking and toasting stages of cornflake production process. Colour was measured by a calibrated computer vision system. Surface fluorescence was measured on compressed samples.

Degradation of β-carotene in amorphous polymer matrices. Effect of water sorption properties and physical state.

Background: The use of encapsulation in amorphous matrices of carbohydrate and/or polymer formed during dehydration processes to enhance the stability and retention of labile compounds is increasing in the food and pharmaceutical industries. Efforts to improve encapsulating properties have been made using mixtures of carbohydrates with proteins or gums in different proportions. The objective of the present work was to study the stability of encapsulated β-carotene and its degradation kinetics in maltodextrin/gum arabic and maltodextrin/gelatin matrices in relation to the physical properties and state of the dehydrated matrix.

Glass transition and time-dependent crystallization behavior of dehydration bioprotectant sugars.

It has been suggested that the crystallization of a sugar hydrate can provide additional desiccation by removing water from the amorphous phase, thereby increasing the glass transition temperature (T(g)). However, present experiments demonstrated that in single sugar systems, if relative humidity is enough for sugar crystallization, the amorphous phase will have a short life. In the conditions of the present experiments, more than 75% of amorphous phase crystallized in less than one month.