I. Peinado

Fabrication and morphological characterization of Biopolymer particles formed by electrostatic complexation of heat treated Lactoferrin and Anionic Polysaccharides

Biopolymer particles fabricated from proteins and/or polysaccharides can be used to encapsulate functional components or to modify various functional properties of materials. In this study, sub-micrometer biopolymer particles were fabricated by electrostatic complexation of heat-denatured protein (lactoferrin, LF) particles with anionic polysaccharides (alginate, carrageenan, or pectin). The aim of the study was to exploit macromolecular electrostatic interactions to form sub-micrometer sized particles and study their stability and morphological characteristics. Initially, protein particles were formed by heat treatment (91 degrees C, 20 min) of a lactoferrin solution (0.2% LF, pH 7), which led to a suspension of protein particles with mean diameter of 200-400 nm and isoelectric point of pI approximately 8.5. Biopolymer particles were then formed by mixing the protein particles with anionic polysaccharides at pH 8 and then lowering the pH to promote electrostatic deposition of polysaccharides onto the protein particle surfaces. The influence of pH (2-11) and ionic strength (0-200 mM NaCl) on the properties and stability of the complexes was studied using turbidity, dynamic light scattering, and electrophoresis measurements. Relatively stable particles could be formed from pH 5 to 8, but appreciable aggregation occurred at lower pH which was attributed to charge neutralization and bridging effects. LF-pectin complexes were relatively stable to salt addition, but LF-carrageenan and LF-alginate complexes exhibited aggregation at higher salt concentrations. These results have important implications for the application of lactoferrin-polysaccharide complexes as functional components in commercial products, such as pharmaceuticals, personal care products, and foods.

Influence of processing on the volatile profile of strawberry spreads made with isomaltulose

A new strawberry spread formulated with fructose and isomaltulose (replacing sucrose partially or totally) and a high percentage of fruit was developed in line with the new trend of healthier products. This work studies the influence of some process variables (percentage of sugar, pectin and citric acid, and time of thermal treatment) on the volatile profile of these spreads with different formulations. The ripeness of the raw strawberries influences the concentrations of some of the compounds in the spreads, such as isobutyl acetate, butyl butyrate, 3-hexen-1-yl acetate or propan-2-ol. The process conditions have an important effect on the volatile profiles. Most of the esters and alcohols decreased whereas 13 new compounds appear, mostly furans (furfural, 2-acetylfurane, 5-methyl furfural, mesifurane) and aldehydes (octanal, nonanal, decanal and benzaldeyhde). In general, the spreads formulated with sucrose-isomaltulose that contained higher levels of pectin and citric acid gave better results in the preservation of the original aromatic compounds in raw strawberries.

Dietary acrylamide: What happens during digestion

Acrylamide is a well-known potentially carcinogen compound formed during thermal processing as an intermediate of Maillard reactions. Three objectives were addressed: the impact of gastric digestion on acrylamide content of French Fries, chips, chicken nuggets, onions rings, breakfast cereals, biscuits, crackers, instant coffee and coffee substitute; the acrylamide content evolution during gastrointestinal digestion of French fries and chips; and the effectiveness of blanching and air-frying on acrylamide mitigation after gastrointestinal digestion. A significant increase (p-value <0.05) in acrylamide content was observed for most of the products after gastric digestion (maximum registered for sweet biscuits, from 30±8 to 150±48µg/kg). However, at the end of the intestinal stage, acrylamide values were statistically similar (p-value=0.132) for French fries and lower than the initial values (before digestion) in potato chips (p-value=0.027). Finally, the low acrylamide content found in blanched and air-fried samples, remained still lower than for deep fried samples even after gastrointestinal digestion.

Effect of saffron (Crocus sativus L.) enrichment on antioxidant and sensorial properties of wheat flour pasta

Saffron, used in cookery as a flavouring and colouring agent, is well-known for its antioxidant and beneficial health properties. In the present work, the effect of saffron addition (0-control, 0.1, 0.2 and 0.4%, w/w) in the formulation of fresh pasta was evaluated on textural, physical-chemical, and sensory properties of the cooked product. Content and retention of the bioactive molecules of saffron (crocins) were evaluated by HPLC along with the corresponding antioxidant activity of enriched pasta. The presence of saffron significantly influenced textural and physical-chemical properties of pasta. Higher saffron concentrations enhanced the antioxidant activity of pasta with the higher values of crocins in samples enriched with 0.4% saffron extract even after 3 min of cooking (4.23-5.06 mg/g db). Sensory analysis showed an increased acceptability of the saffron enriched pasta for all descriptors selected (visual aspect, colour, aroma, taste, chewiness, hardness, gumminess and overall acceptability).