Inulin potential for encapsulation and controlled delivery of Oregano essential oil

The ability of inulin, a prebiotic material, as encapsulation matrix was explored. Microcapsules of Raftiline were produced by spray drying inulin solutions at different solids content (5, 15 and 25%) at 120, 155 and 190 °C, according to a Central Composite Rotatable design. Produced capsules were analysed for morphology and size by SEM and physiochemical characterized by DSC, IR and RAMAN. Oregano essential oil was incorporated in the inulin solutions at 15% solids basis and the emulsions dried at the same conditions. The above mentioned methodologies were applied to evaluate the encapsulation ability and the changes induced by the presence of the EO in capsules morphology and structure. Furthermore the kinetics and amount of release was assessed by a spectrophotometric method. Results showed that it was possible to produce regular spherical inulin microcapsules (3–4.5 μm) for all the tested experimental conditions. According to IR and Raman results mainly drying temperature affected the structure of the capsules, three groups being clearly formed. These groups could be related to the morphology of inulin crystals. The EO was successfully encapsulated in the system as demonstrated by IR and Raman analysis. The differences found in the EO releasing amount, make clear that different degrees of core material retention is achieved, what should be related to structural changes in the matrix wall, denoting in some processing conditions interactions phenomena among inulin and EO. Those different releasing profiles patterns may be quite useful in finding different potential uses for the encapsulates.Thanks are due for the financial support given by Portuguese Foundation for Science and Technology (FCT) through the project PTDC/AGR/ALI/67194/2006 and through a post-doctoral grant of first author (SFRH/BPD/44200/2008) supported by programme QREN - POPH - Tipologia 4.1. The authors also express their gratitude to Mr Octavio Chaveiro from INIAV for the given support in microscopy studies

Metodologias integradas para a conservação de kiwi minimamente processado

Doutoramento em Engenharia Agro-Industrial -Instituto Superior de AgronomiaThe main objective of the present work was the development of methodologies able to increase and/or maintain the quality of minimally processed kiwifruit during storage. Several treatments were tested at different steps of fresh-cut kiwifruit production process. Fruit maturity stage was a key factor determining both fruit ability for minimal processing and the appropriate treatment selection for appliance. Moderate heat treatments, applied to whole fruit, were efficient in preserving firmness of ready-to-eat kiwifruit during storage, but fruits must be at a firm ripe stage. Heat treatment that conduces to better results was 45 ºC/25 min. The beneficial effect of this treatment could be enhanced with calcium dips but, the synergistic effect between treatments is only observed if the treatments were done sequentially. Pectin methylesterase activation by heat treatment with calcium pectates formation was the main mechanism involved in fruit slices firmness maintenance. From tested methods, UV-C treatment was the most effective in reducing microbial loads of minimally processed kiwifruit, maintaining the levels always below the recommended limits. This treatment also induced fruit physiology changes allowing a better retention of fruit slices firmness during storage

The effect of calcium dips combined with mild heating of whole kiwifruit for fruit slices quality maintenance

The effect of moderate heat treatment combined with calcium dips on the quality of minimally processed kiwifruit was studied. Whole fruits were treated for 25 min at 45 C by dipping in deionised water or CaCl2 solutions (1%, 2% and 3% (w/v)) and cooled to 4 C. Twenty-four hours later fruits were peeled, sanitized, cut into slices and packed. The firmness of kiwifruit slices’ was subsequently evaluated during 8 days of storage. Calcium content, pectinmethylesterase activity and heat shock proteins accumulation were also investigated. Heat treatment conducted in water induced a firming effect and avoid softening of fruit slices while calcium dips had a marginal effect on this parameter. A calcium loss was observed due to dip treatment, but this effect was minimized when treatment was conducted in 3% CaCl2 solution. The firming effect provided is due to the activation of pectinmethylesterase and the presence of calcium in treatment solution reduces or inhibits enzyme activation. Under the tested conditions, no heat shock proteins de novo synthesis was detecte

Texture, microstructure and consumer preference of mango bars jellified with gellan gum

Studies for the development of a novel convenient fruit product based on mango puree and gellan gum were carried out. Two gellan types (low acyl-L and high acyl-H) used in specific L/H ratios (75/25, 50/50, 25/75) for an overall concentration of 1 g of gellan/100 g of puree were tested, in order to design different mango bars. The influence of the L/H gellan ratio on their texture properties (TPA and SR tests), microstructure (Cryo-Scanning Electron Microscopy) and texture sensory acceptance (Preference- Ranking test) was studied. The results obtained enabled to separate the bars in two groups: the ones showing greater hardness and brittleness (only L gellan, and L/H at the ratios of 75/25 and 50/50); and those presenting a softer structure with higher cohesiveness and springiness values (L/H of 25/75 and only H gellan). The microstructure of mango bars was consistent with the texture results. Those presenting higher hardness have shown a microstructure composed of a denser biopolymer network with lower pore size; while for softer bars with higher springiness, larger pores and thin strings were observed. From the Preference-Ranking test, the most appreciated mango bar in terms of texture was the one prepared with a L/H ratio of 25/75.info:eu-repo/semantics/publishedVersio

The effect of the matrix system in the delivery and in-vitro bioactivity of microencapsulated oregano essential oil

Microencapsulation allows bioactive compounds protection from external factors. Innovation in food industry often requires adding functional ingredients, to tailor flavour and texture, to improve preservation, to control bioactive compounds stability and controlled release during processing/storage. Oregano, besides richness in aroma compounds, is also known by potential antioxidant and antimicrobial activities. These sensitive compounds need protection in order to allow their use in a wider range of processes. In this study, oregano essential oil (EO) was microencapsulated by spray/freeze drying in: rice starch (with/without bonding agents), gelatine/sucrose and inulin, dried at different temperatures. Microencapsulates were analysed for morphology and structure (SEM, CLSM, X-ray diffraction and FTIR). Releasing ability of entrapped EO (UV–VIS spectroscopy) was evaluated by diffusion coefficient (D). Antioxidant activity (AA) - ORAC and HORAC- and antimicrobial activities against pathogens were evaluated. Rice starch spherules, presenting interconnecting cavities, were formed. Spray-dried inulin and gelatine/sucrose systems formed continuous walled and smooth surface spherical capsules (3-4.5 and 0.9-10m, respectively). EO was uniformly distributed inside the structures (CLSM) and its presence confirmed by FTIR. Depending on the system, D varied among 10-13 (starch), 10-13-10-15, (gelatine/sucrose) and 10-16 m2/s (inulin). In starch system, D was mainly influenced by the gelatin concentration, increasing with it. X- ray diffraction and FTIR results suggest some kind of linkage between gelatine and starch. Spray-dried gelatine/sucrose system, revealed to be unsuitable for EO encapsulation due to capsules disintegration but freeze-drying was effective. The D of EO from inulin capsules decreases when these are produced above 140 ºC. The impact of encapsulation method on EO bioactivity and product stability during 6 months, was verified through the determination of microcapsules AA, using free EO value as reference. The results obtained provide information on the release/stability of oregano EO from different matrices, relevant for functional ingredients microencapsulation

Effect of the matrix system in delivery and in vitro bioactivity of microencapsulated Oregano essential oil

Available at ScienceDirectThe effect of encapsulating matrix on retention, protection and delivery of Oregano essential oil (EO) was studied. EO was encapsulated in rice starch porous spheres, inulin and gelatine/sucrose capsules by spray drying. Gelatine/sucrose matrix was also dried by freeze drying. Experimental designs were applied to test the effect of bonding agents and solids content for rice starch and drying temperature and solids content for inulin and gelatine/sucrose systems. The ratio of gelatine/sucrose was also tested. EO was identified (confocal laser scanning microscopy and FT-IR) in all tested matrices and the release profiles, antioxidant activity and antimicrobial activity of encapsulates evaluated. Results showed that the three tested materials are able to encapsulate Oregano EO. Higher diffusion coefficients were obtained for starch microcapsules (about 10 13 m2/s) followed by spray-dried gelatine/sucrose systems (about 10 15 m2/s) and inulin microcapsules (about 10 16 m2/s). Gelatine/sucrose microparticles exhibit high antioxidant and antimicrobial activity while inulin and rice starch microencapsulates ensure higher stabilit

Effect of the matrix system in the delivery and in vitro bioactivity of microencapsulated Oregano essential oil

The effect of encapsulating matrix on retention, protection and delivery of Oregano essential oil (EO) was studied. EO was encapsulated in rice starch porous spheres, inulin and gelatine/sucrose capsules by spray drying. Gelatine/sucrose matrix was also dried by freeze drying. Experimental designs were applied to test the effect of bonding agents and solids content for rice starch and drying temperature and solids content for inulin and gelatine/sucrose systems. The ratio of gelatine/sucrose was also tested. EO was identified (confocal laser scanning microscopy and FT-IR) in all tested matrices and the release profiles,antioxidant activity and antimicrobial activity of encapsulates evaluated. Results showed that the three tested materials are able to encapsulate Oregano EO. Higher diffusion coefficients were obtained for starch microcapsules (about 1013 m2/s) followed by spray-dried gelatine/sucrose systems (about 1015 m2/s) and inulin microcapsules (about 1016 m2/s). Gelatine/sucrose microparticles exhibit high antioxidant and antimicrobial activity while inulin and rice starch microencapsulates ensure higher stability.Portuguese Foundation for Science and Technology (FCT) - PTDC/AGR/ALI/67194/2006, SFRH/BPD/44200/2008, QREN – POPH – Tipologia 4.1

Métodos alternativos de descontaminação de kiwi minimamente processado

[POR] Nos últimos anos tem-se vindo a verificar um incremento da procura de frutos minimamente processados, preparados de modo a manter as suas características sensoriais de frescura e qualidade nutricional. Simultaneamente assiste-se a uma crescente preocupação com a segurança alimentar. A descontaminação de produtos minimamente processados, a nível industrial, é normalmente efectuada por imersão do produto em água clorada refrigerada (100-200 ppm de cloro livre) no entanto, a eficiência destes tratamentos para além de ser baixa pode conferir cheiro a cloro e levar à formação de compostos organoclorados tóxicos. A substituição parcial ou integral do cloro por métodos de descontaminação alternativos tem vindo a ser objecto de estudo. No presente trabalho foram estudadas novas metodologias de descontaminação - choque térmico (95 ºC / 45 s), ozonização (0,4 ppm / 2 min) e radiação não ionizante UV (237 nm / 4 min). A descontaminação em água clorada (125 ppm Cl- livre; Ph 6) foi efectuada como controlo. O choque térmico foi aplicado ao fruto antes da operação de descasque, tendo as operações subsequentes sido efectuadas nas melhores condições sanitárias possíveis. Os restantes tratamentos de descontaminação foram aplicados após descasque. Foi avaliada a eficiência de descontaminação (mesófilos totais, bolores e leveduras, bacterias lácticas e microrganismos psicrotróficos) e o impacto dos tratamentos na cor e dureza do fruto minimamente processado. Os resultados obtidos evidenciam que o kiwi é um fruto que pelo seu reduzido pH (pH≈ 3,5) não apresenta elevada susceptibilidade ao desenvolvimento microbiano, tendo-se obtido contagens válidas apenas para microrganismos mesófilos totais. Os métodos alternativos estudados são eficazes na descontaminação, preservando a qualidade do fruto sem efeitos residuais

The effect of fruit cultivar/origin and storage time on sorbets quality

Fruit quality is one of the main factors that influence the sorbets’ quality. The aim of this study was to evaluate the effects of two different cultivars of five fruits (mandarin, lemon, melon and mango) or origin (strawberries) on the overall quality of sorbets, right after being produced and after being preserved for 21 days at 18 C. Total soluble solids (TSS), titratable acidity (TA) and firmness were used to characterize the fruits. Colour, pH, antioxidant capacity (AC) and total phenolic content (TPC), as well as sensory attributes, were evaluated on fruits and respective sorbets. Fruit processing led to a loss of TPC and AC. Nevertheless, no significant changes were observed on sorbets over storage time. In spite of chemical, physical and sensorial differences registered among fruits from different cultivars or origin, the sensory profiles of sorbets from the same pair of studied fruits are very similar. Multivariate analysis clearly shows that the sorbets produced maintain the same sensorial quality regardless of the cultivar or the origin of the fruitsinfo:eu-repo/semantics/publishedVersio