MALDI-TOF to compare polysaccharide profiles from commercial health supplements of different mushroom species.

In this work MALDI-TOF mass spectroscopy was investigated to characterise the β-glucan profiles of several commercial health supplements, without any derivatisation or purification pre-treatment. The effect of two solvents (water and dimethyl sulfoxide) and two MALDI matrices (2,5-dihydroxybenzoic acid and 2',4',6'-trihydroxyacetophenone) was first evaluated on dextran standards. MALDI-TOF was found as a useful and quick technique to obtain structural information of diverse food supplements based on mushroom extracts.

Plasticized poly(lactic acid)-poly(hydroxybutyrate) (PLA-PHB) blends incorporated with catechin intended for active food-packaging applications.

Active biobased packaging materials based on poly(lactic acid)-poly(hydroxybutyrate) (PLA-PHB) blends were prepared by melt blending and fully characterized. Catechin incorporation, as antioxidant compound, enhanced the thermal stability, whereas its release was improved by the addition of acetyl(tributyl citrate) (ATBC) as plasticizer. Whereas the incorporation of ATBC resulted in a reduction of elastic modulus and hardness, catechin addition produced more rigid materials due to hydrogen-bonding interactions between catechin hydroxyl groups and carbonyl groups of PLA and PHB.

Analytical determination of flavonoids aimed to analysis of natural samples and active packaging applications.

Several HPLC and UHPLC developed methods were compared to analyse the natural antioxidants catechins and quercetin used in active packaging and functional foods. Photodiode array detector coupled with a fluorescence detector and compared with LTQ-Orbitrap-MS was used. UHPLC was investigated as quick alternative without compromising the separation, analysis time shortened up to 6-fold.

Enhancing the release of the antioxidant tocopherol from polypropylene films by incorporating the natural plasticizers lecithin, olive oil, or sunflower oil.

In this work, natural plasticizers-modified polypropylenes intended for food active packaging were developed. Sunflower oil, olive oil, and soy lecithin, without any known harmful effects or toxicity, were employed as natural plasticizers, also implementing the attractiveness of using synthetic plastics on active packaging developments. Their incorporation during the extrusion of polypropylene was tried as a means to obtain polymers with improved diffusion paths, allowing differences in antioxidant release rates for active packaging materials.

Improving the capacity of polypropylene to be used in antioxidant active films: incorporation of plasticizer and natural antioxidants.

Two types of active antioxidant food packages with improved release properties, based on polypropylene (PP) as one of the most common polymers used in food-packaging applications, were developed. Incorporation of catechin and green tea as antioxidant provided PP with 6 times higher stabilization against thermal oxidation. Release of natural antioxidants (catechins, gallic acid, caffeine, and quercetin) into various food simulants from that nonpolar matrix were improved by blending poly(propylene glycol)-block-poly(ethylene glycol)-block-poly(propylene glycol) (PPG-PEG-PPG) as plasticizer into the polymer formulation.

Effect of PPG-PEG-PPG on the tocopherol-controlled release from films intended for food-packaging applications.

The feasibility of novel controlled release systems for the delivery of active substances from films intended for food packaging was investigated. Because polyolefins are used highly for food-packaging applications, the reported high retention degree of antioxidants has limited their use for active packaging. Thus, in this study, PP films modified with different chain extenders have been developed to favor and control the release rates of the low molecular weight antioxidant tocopherol.

Preparation, evaluation and characterization of quercetin-molecularly imprinted polymer for preconcentration and clean-up of catechins.

Molecularly imprinted polymer (MIP) for solid extraction and preconcentration of catechins have been successfully prepared by a thermal polymerization method using quercetin as template, 4-vinylpyridine as functional monomer and ethylene glycol dimethacrylate as crosslinker. A solution mixture of acetone and acetonitrile was used as porogen. Systematic investigations of the influence of monomer, cross-linker, porogen, as well as polymerization conditions on the properties of the MIPs were carried out.