Carmen S. Favaro-Trindade

Microencapsulation of aspartame by double emulsion followed by complex coacervation to provide protection and prolong sweetness.

The objective of this work was to microencapsulate aspartame by double emulsion followed by complex coacervation, aiming to protect it and control its release. Six treatments were prepared using sunflower oil to prepare the primary emulsion and gelatin and gum Arabic as the wall materials. The microcapsules were evaluated structurally with respect to their sorption isotherms and release into water (36°C and 80°C). The microcapsules were multinucleated, not very water-soluble or hygroscopic and showed reduced rates of equilibrium moisture content and release at both temperatures. FTIR confirmed complexation between the wall materials and the intact nature of aspartame. The results indicated it was possible to encapsulate aspartame with the techniques employed and that these protected the sweetener even at 80°C. The reduced solubility and low release rates indicated the enormous potential of the vehicle developed in controlling the release of the aspartame into the food, thus prolonging its sweetness.

Stability of free and immobilized Lactobacillus acidophilus and Bifidobacterium lactis in acidified milk and of immobilized B. lactis in yoghurt

Este trabalho avaliou a estabilidade de Bifidobacterium lactis (Bb-12) e de Lactobacillus acidophilus (La-05) nas formas livre e imobilizada em alginato de calcio, em leite e leite acidificado (pHs 5.0, 4.4 e 3.8), e a estabilidade de B. lactis imobilizado em iogurte (fermentado ate pH 4.2), durante 28 dias de estocagem refrigerada. Tambem foi estudada a eficiencia de dois meios de cultura (agar MRS modificado e Reinforced Clostridial Agar, acrescido de Prussian Blue) para enumerar B. lactis em iogurte. Agar Lee foi usado para enumeracao de Streptococcus thermophilus e Lactobacillus delbrueckii ssp. bulgaricus quando B. lactis era enumerado no meio MRS. Ambos os microrganismos, nas formas livre e imobilizada, apresentaram uma taxa de sobrevivencia adequada nos leites acidificados, uma vez que houve reducao de apenas um ciclo log, apos 21 dias de estocagem refrigerada. O numero de celulas viaveis de B. lactis imobilizado mostrou um declinio gradual durante o periodo de armazenamento do iogurte, passando de 108 ufc/ml ate nao ter mais contagem na diluicao 10-1. Quando as culturas nao estavam em equilibrio, o meio MRS modificado foi mais eficiente para a contagem de B. lactis em iogurte. Em vista destes resultados pode-se concluir que ambos os microrganismos podem ser incorporados em leite e leite acidificados, haja visto que a reducao na populacao foi pequena durante o periodo de armazenagem estudado. A presenca da cultura tradicional de iogurte parece ter afetado negativamente a sobrevivencia de B. lactis e a imobilizacao nao proveu protecao as celulas, em nenhum dos tratamentos estudados.

Microcapsules of a Casein Hydrolysate: Production, Characterization, and Application in Protein Bars

The aim of this work was to encapsulate a casein hydrolysate by spray drying using maltodextrins (DE 10 and 20) as wall materials and to evaluate the efficiency of the microencapsulation in attenuating the bitter taste of the hydrolysate using protein bars as the model system. Microcapsules were evaluated for morphology (SEM), particle size, hygroscopicity, solubility, thermal behavior (DSC), and bitter taste with a trained sensory panel by a paired comparison test (nonencapsulated samples vs. encapsulated samples). Bars were prepared with the addition of 3% casein hydrolysate at free or both encapsulated forms, and were then evaluated for their moisture, water activity (aw) and for their bitter taste by a ranking test. Microcapsules were of the matrix type, having continuous surfaces with no apparent porosity for both coatings. Both encapsulated casein hydrolysates had similar hygroscopicity, and lower values than free encapsulated hydrolysates. The degree of hydrolysis of the maltodextrin influenced only the particle size and Tg. The sensory panel considered the protein bars produced with both encapsulated materials less bitter (p < 0.05) than those produced with the free casein hydrolysates. Microencapsulation by spray drying with maltodextrin DE 10 and 20 was successful to attenuate the bitter taste and the hygroscopicity of casein hydrolysates.

Microencapsulation of xylitol by double emulsion followed by complex coacervation.

The objective of this study was to produce and characterise xylitol microcapsules for use in foods, in order to prolong the sweetness and cooling effect provided by this ingredient. Complex coacervation was employed as the microencapsulation method. A preliminary double emulsion step was performed due to the hydrophilicity of xylitol. The microcapsules obtained were characterised in terms of particle size and morphology (optical, confocal and scanning electron microscopy), solubility, sorption isotherms, FTIR, encapsulation efficiency and release study. The microcapsules of xylitol showed desirable characteristics for use in foods, such as a particle size below 109 μm, low solubility and complete encapsulation of the core by the wall material. The encapsulation efficiency ranged from 31% to 71%, being higher in treatments with higher concentrations of polymers. Release of over 70% of the microencapsulated xylitol in artificial saliva occurred within 20 min.

Fabrication of solid lipid microcapsules containing ascorbic acid using a microfluidic technique

The importance of ascorbic acid (AA) in the human diet has motivated food researchers to develop AA-fortified food products. However, this compound is very unstable. The aim of this work was to produce solid lipid microcapsules (SLMs) loaded with AA using microfluidic technology. The morphology of the SLMs was analysed by optical, scanning electron and confocal microscopy. We determined the encapsulation efficiency, particle size and stability of the encapsulated material. Two different means of enhancing the encapsulation efficiency and stability of AA were demonstrated: a pore blocking method and a micromolecule-chelating agent within the core. The results indicated the enormous potential of the designed vehicle to prevent AA degradation in a food product; additionally, this vehicle could mask the acidic taste of AA.

Preparo e caracterização de microcápsulas de oleoresina de páprica obtidas por atomização

Palavras-chave: SUMMARY PREPARATION AND CHARACTERIZATION OF PAPRIKA OLEORESIN MICROCAPSULES OBTAINED BY SPRAY DRYING. Paprika ( L.) is a bright red coloring product of large use by the food industry. Rich in carotenoids, paprika is susceptible to oxidative degradation. Considering these aspects, this research is aimed to microencapsulate paprika oleoresin and to evaluate morphological characteristics, distribution and average particle size and the solubility of microencapsulated paprika oleoresin. The microencapsulation was carried out by spray drying, in porous agglomerates of rice starch/gelatin and arabic gum. Scanning electron microscopy analysis showed, for arabic gum microcapsules, a cylindrical shape with a continuous wall with no apparent porosity or cracks and the core was distributed within the wall. The porous agglomerates of rice starch/gelatin microcapsules also presented a cylindrical shape; the walls were formed by the granules of rice starch, which was glued by gelatin; however the structure was shown to be porous. Both materials presented unimodal distribution, with an average particle size of 16 and 20.3 m for arabic gum and starch/gelatin microcapsules, respectively. In spite of that it is possible to microencapsulate paprika oleoresin with both materials using the spray drying process, the morphologycal analysis revealed that arabic gum seems to be a more effective barrier to the core material. Obtained results also show that the temperatures used in the microencapsulation were adequate, the size of the microcapsules were inside the range used by this kind of process and the solubility was excellent. microencapsulation; morphology; spray drying; paprika oleoresin; arabic gum; agglomerates of rice starch/gelatin. Capsicum annuum µ

Functional properties and stability of spray-dried pigments from Bordo grape (Vitis labrusca) winemaking pomace.

The stability of anthocyanin and phenolic compounds, the antioxidant capacity, the antimicrobial activity and the capacity to inhibit arginase from Leishmania were evaluated in spray-dried powders from Bordo grape winemaking pomace extract. The pigments were produced using maltodextrin as the carrier agent at concentrations varying from 10% to 30% and air entrance temperatures varying from 130 to 170°C. A sample of freeze-dried extract without the carrier was also evaluated. The anthocyanins in the spray-dried samples showed good stability during storage, better than the freeze-dried and liquid extracts. The samples were capable of inhibiting the growth of Staphylococcus aureus and Listeria monocytogenes and showed high inhibitory capacity against the enzyme arginase from Leishmania. These results provide evidence that Bordo grapes from the winemaking process have the potential to be used as natural pigments with functional properties.

Microencapsulation of Bifidobacterium animalis subsp. lactis and Lactobacillus acidophilus in cocoa butter using spray chilling technology

In the present study, the cells of Bifidobacterium animalis subsp. lactis (BI-01) and Lactobacillus acidophilus (LAC-04) were encapsulated in cocoa butter using spray-chilling technology. Survival assays were conducted to evaluate the resistance of the probiotics to the spray-chilling process, their resistance to the simulated gastric and intestinal fluids (SGF and SIF), and their stability during 90 days of storage. The viability of the cells was not affected by microencapsulation. The free and encapsulated cells of B. animalis subsp. lactis were resistant to both SGF and SIF. The micro-encapsulated cells of L. acidophilus were more resistant to SGF and SIF than the free cells; the viability of the encapsulated cells was enhanced by 67%, while the free cells reached the detection limit of the method (103 CFU/g). The encapsulated probiotics were unstable when they were stored at 20 °C. The population of encapsulated L. acidophilus decreased drastically when they were stored at 7 °C; only 20% of cells were viable after 90 days of storage. The percentage of viable cells of the encapsulated B. animalis subsp.lactis, however, was 72% after the same period of storage. Promising results were obtained when the microparticles were stored at −18 °C; the freeze granted 90 days of shelf life to the encapsulated cells. These results suggest that the spray-chilling process using cocoa butter as carrier protects L. acidophilus from gastrointestinal fluids. However, the viability of the cells during storage must be improved.

Effects of Culture, pH and Fat Concentration on Melting Rate and Sensory Characteristics of Probiotic Fermented Yellow Mombin (Spondias mombin L) Ice Creams

Twelve fermented yellow mombin ice creams were produced with different starter cultures (Lactobacillus acidophilus 74-2, L. acidophilus LAC 4 and yoghurt starter culture), final pH (4.5 and 5) and concentrations of added cream (5 and 10%). Probiotic culture stability, melting properties and sensory acceptance were evaluated in ice cream samples. The mixes were frozen and stored for 105 days at -18°C. The melting rates were lower for samples with a pH of 4.5. Both probiotic cultures resisted the freezing process and, although a tendency for the counts to decrease during storage was detected, they were still higher than 10 6 cfu/g after 105 days, even in products with a pH of 4.5. A pH 4.5, 5% cream and L. acidophilus LAC 4 ice cream received significantly higher sensory scores when compared with pH 5, 10% cream and L. acidophilus 74-2 ice cream. The fermented yellow mombin ice cream was a suitable food for the delivery of L. acidophilus strains, with excellent viability and acceptable sensory characteristics.

Effect of spray drying on the sensory and physical properties of hydrolysed casein using gum arabic as the carrier

This study was aimed at spray drying hydrolysed casein using gum Arabic as the carrier agent, in order to decrease the bitter taste. Three formulations with differing proportions of hydrolysed casein: gum Arabic (10:90, 20:80 and 30:70) were prepared and characterized. They were evaluated for their moisture content, water activity, hygroscopicity, dispersibility in water and in oil, particle size and distribution, particle morphology, thermal behaviour (DSC) and bitter taste by a trained sensory panel using a paired-comparison test (free samples vs. spray dried samples). The proportion of hydrolysed casein did not affect the morphology of the microspheres. The spray drying process increased product stability and modified the dissolution time, but had no effect on the ability of the material to dissolve in either water or oil. The sensory tests showed that the spray drying process using gum Arabic as the carrier was efficient in attenuating or masking the bitter taste of the hydrolysed casein.