Fostering Lavender as a Source for Valuable Bioactives for Food and Pharmaceutical Applications through Extraction and Microencapsulation.

Lavender flowers were used in this study as a source of phytochemicals as naturally occurring antioxidants. Two different extraction techniques were applied, such as ultrasound-assisted (UAE) and supercritical fluids (SCE) methods. The comparative evaluation of the phytochemicals profile evidenced a higher content of chlorophyll a and b of 5.22 ± 0.12 mg/g dry weight (D.W.) and 2.95 ± 0.16 mg/g D.W, whereas the carotenoids content was 18.24 ± 0.04 mg/g D.W. in the SCE extract. Seven main compounds were found in both extracts: ß-linalool, eucalyptol, linalool acetate, ß-trans-ocimene, and limonene in SCE and linalool acetate, ß-linalool, 6-methyl-2-(2-oxiranyl)-5-hepten-2-ol, linalool oxide, lavandulyl acetate and camphor in UAE. The (n-3) acids had a higher contribution in SCE. The extracts were microencapsulated in different combinations of wall materials based on polysaccharides and milk proteins. The four variants showed different phytochemical and morphological profiles, with a better encapsulating efficiency for proteins (up to 98%), but with a higher content of encapsulated carotenoids for polysaccharides, the latter showing remarkable antimicrobial activity against selected microorganisms. Carboxymethyl cellulose and whey proteins led to a double encapsulation of lipophilic compounds. The powders were tested in two food matrices as ingredients, with multiple targeted functions, such as flavoring, antimicrobial, antioxidant activity that can successfully replace synthetic additives.

The kinetics of the swelling process and the release mechanisms of Coriandrum sativum L. essential oil from chitosan/alginate/inulin microcapsules.

The encapsulation by spray drying method of coriander essential oil (CEO) in various materials (chitosan, alginate, chitosan/alginate, chitosan/inulin) was studied. The viscoelastic properties of the oil-in-water (O/W) emulsions and the characteristics of CEO-loaded microcapsules like morphology, moisture, wettability, solubility, flowability properties, swelling and release mechanisms were investigated. The chitosan microcapsules had a brain-like structure while the alginate and chitosan/alginate microcapsules are spherical with a smooth surface. The Compressibility Index (CI=29.09-32.25%) and Hausner Ratio (HR=1.38-1.44) values showed that all the microcapsules prepared correspond to the "poor" flowability powders group. The chitosan microcapsules exhibited the maximum release rate at pH 2.5 while the alginate microcapsules exhibited the maximum release rate at pH 6.5. Kinetics and mechanism of CEO release were studied using various mathematical models such as, zero order, first order, Higuchi model and Peppas model. The diffusional exponent (n) values of Peppas equation explains a non Fickian transport mechanism and diffusion or diffusion-swelling controlled process.

Exploring the heat-induced structural changes of ß-lactoglobulin -linoleic acid complex by fluorescence spectroscopy and molecular modeling techniques.

Linoleic acid (LA) is the precursor of bioactive oxidized linoleic acid metabolites and arachidonic acid, therefore is essential for human growth and plays an important role in good health in general. Because of the low water solubility and sensitivity to oxidation, new ways of LA delivery without compromising the sensory attributes of the enriched products are to be identified. The major whey protein, ß-lactoglobulin (ß-Lg), is a natural carrier for hydrophobic molecules. The thermal induced changes of the ß-Lg-LA complex were investigated in the temperature range from 25 to 85 °C using fluorescence spectroscopy techniques in combination with molecular modeling study and the results were compared with those obtained for ß-Lg. Experimental results indicated that, regardless of LA binding, the polypeptide chain rearrangements at temperatures higher than 75 °C lead to higher exposure of hydrophobic residues causing the increase of fluorescence intensity. Phase diagram indicated an all or none transition between two conformations. The LA surface involved in the interaction with ß-Lg was about 497 Çº(2), indicating a good affinity between those two components even at high temperatures. Results obtained in this study provide important details about heat-induced changes in the conformation of ß-Lg-LA complex. The thermal treatment at high temperature does not affect the LA binding and carrier functions of ß-Lg.

Monitoring the heat-induced structural changes of alkaline phosphatase by molecular modeling, fluorescence spectroscopy and inactivation kinetics investigations.

The heat induced conformational changes of calf alkaline phosphatase (ALP) were analyzed using different methods, based on fluorescence spectroscopy, molecular modeling and inactivation studies. Experimental studies were conducted in buffer solution in the temperature range between 25 and 70 °C. Molecular dynamic (MD) simulation provided details on thermally induced changes in ALP structure, highlighting that heating favored the hydrophobic exposure and important alteration of the catalytic site above 60 °C. Additional information to MD data were obtained by using different fluorescence spectroscopy methods, which revealed a complex mechanism of thermal denaturation. Therefore, the emissive properties indicated an unfolding of ALP at temperatures below 60 °C, whereas at higher temperatures, the polypeptides chains fold leading to a higher exposure of Trp residues. In order to establish a structure-function relationship, the results were correlated with inactivation studies of ALP in buffer at pH 9.0. The inactivation data were fitted using a first-order kinetic model, resulting in an activation energy value of 207.26 ± 21.68 kJ · mol(-1).

Comparison of thawing assisted by low-intensity ultrasound on technological properties of pork Longissimus dorsi muscle.

The objective of the present study was to analyses technological and textural properties of pork thawed by low intensity ultrasound compared to meat thawed conventionally in air (control) or by immersion in water. The pork thawing was done by means of a generator of constant frequency, with adjusting ultrasound intensity, coupled with a transducer plate and a water bath. The frequency of 25 kHz and the intensity of 0.6 W/cm(2) allowed reducing by 87 % the time required for thawing from -5 °C to -1 °C as well as the overall thawing time as compared to thawing in air. Using intensity of 0.2, 0.4, and 0.6 W/cm(2) thawing rates were 0.62, 0.73, 1 °C/min, versus 0.16 °C/min in the control. The textural and technological properties of meat thawed by ultrasound are not impaired by the significant lowering of thawing time; there were no large mass loss or modification of meat ultrastructure as compared to control.