David González-Gómez

Different postharvest strategies to preserve broccoli quality during storage and shelf life: Controlled atmosphere and 1-MCP

Broccoli (Brassica oleracea var. italica) is a vegetable that requires the application of postharvest techniques to extend its marketability. Controlled atmosphere and 1-MCP treatments are most used to extend the shelf life of broccoli and reduce post-harvest deterioration. The aim of this study was to evaluate the visual, physicochemical and functional changes of broccoli head samples stored at 1-2 °C and 85-90% relative humidity (RH) in air (Control samples), under controlled atmospheres (10% O(2) and 5% CO(2)) (CA samples) and treated with 1-MCP (0.6 μL/L). After storage all samples were maintained at 20 °C for 2 and 4 days, in order to assess their shelf life. The most suitable postharvest treatment to extend broccoli quality during storage and shelf life, in terms of maintaining the visual quality and reducing loss of health-promoting compounds, was achieved by storage under controlled atmosphere conditions. The use of 1-MCP reduced the loss of green colour and chlorophyll pigments, but only during cold storage not during shelf life at 20 °C.

In vitro assays of the antibacterial and antioxidant activity of aqueous leaf extracts from different Prunus salicina Lindl. cultivars.

The growing interest in the substitution of synthetic food antioxidants and antimicrobial additives by natural ones has fostered research on vegetable sources and on the screening of raw materials, for identifying new antioxidants and antimicrobial natural agents. The aim of the present study was to assess total phenolic contents and determine polyphenolic composition, related antioxidative and antimicrobial properties of plum leaves extracts from six cultivars. It was observed that the content of total phenolic compounds was cultivar dependent. High antioxidant capacity has been observed and related to the relative amounts of polyphenolic compounds with good antioxidant properties. The antimicrobial activity was confirmed against Listeria innocua and Escherichia coli, and it has found to be related with the high phenolic contents. Our results suggest that the use of plum leaf extracts is a feasible alternative as antibacterial and antioxidant agents to prevent the deterioration of stored foods by bacteria and oxidation.

A jerte valley cherry product provides beneficial effects on sleep quality. Influence on aging

ObjectiveIn the present work, we evaluated the effect of the intake of a Jerte Valley cherry-based product (JVCP), compared to a placebo product, on sleep quality, urinary 6-sulfatoxymelatonin (aMT6-s) levels and the serum concentration of interleukin-1β (IL-1β), tumor necrosis factor α (TNF-α) and interleukin-8 (IL-8).DesignThis was a blind, placebo-controlled, randomized, crossover study.SettingUniversity of Extremadura (Spain).ParticipantsTen young (20–30 years old), ten middle-aged (35–55 years old), and ten elderly (65–85 years old) participants.InterventionA placebo (Kool-Aid®) or JVCP (patent no. ES 2342141 B1) were consumed twice a day, as lunch and dinner desserts.MeasurementsActigraphic monitoring was used to record and display the temporal patterns of the individuals’ activity and rest. Urinary aMT6-s and serum cytokines (IL-1β, TNF-α and IL-8) were also determined.ResultsThe consumption of the JVCP improved the nocturnal rest, measured by sleep efficiency, number of awakenings, total nocturnal activity, sleep latency, assumed sleep, actual sleep time and immobility. Moreover, it was detected an increase in both the levels of aMT6-s found in first-void morning urine and the concentrations of serum pro-somnogenic cytokines obtained from samples collected at the acrophase of the melatonin rhythm (1.00 am) in all experimental age groups after the JVCP consumption. Generally, better results were obtained with advancing age.ConclusionThe ingestion of the JVCP may contribute to establish a high-quality sleep and be used as a potential nutraceutical tool to prevent sleep disorders with the advance of age.

Micro-encapsulation of refined olive oil: influence of capsule wall components and the addition of antioxidant additives on the shelf life and chemical alteration.

BACKGROUND Although refined olive oils (ROOs) exhibit lower quality and less stability toward thermal stress than extra-virgin olive oils, these types of oil are gaining importance in the food industry. The inclusion of ROOs in processed food may alter the oxidative stability of the manufactured products, and therefore having technological alternatives to increase oil stability will be an important achievement. For this reason the main goal of this study was to assess the influence of the micro-encapsulation process on the ROO chemical composition and its oxidative stability. Factors such as microcapsule wall constituents and the addition of the antioxidant butyl hydroxytoluene were investigated in order to establish the most appropriate conditions to ensure no alteration of the refined olive oil chemical characteristics. RESULTS The optimised methodology exhibited high encapsulation yield (>98%), with micro-encapsulation efficiency ranging from 35 to 69% according to the nature of the wall components. The encapsulation process slightly altered the chemical composition of the olive oil and protected the oxidative stability for at least 11 months when protein components were included as wall components. CONCLUSION It was concluded that the presence of proteins constituents in the microcapsule wall material extended the shelf life of the micro-encapsulated olive oil regardless the use of antioxidant additives.

The consumption of a Jerte Valley cherry product in humans enhances mood, and increases 5-hydroxyindoleacetic acid but reduces cortisol levels in urine.

PURPOSE Jerte Valley cherries contain high levels of tryptophan, serotonin, and melatonin. These molecules have been shown to be involved in mood regulation. It has been suggested that a complex inter-relationship between brain serotonin, circulating levels of cortisol (the major stress hormone), and the hypothalamus-pituitary-adrenal axis exists in the regulation of stress responses, where cortisol and serotonin act as markers of mood disturbances. Moreover there is growing evidence that altered HPA activity is associated with various age-related pathologies. The present study evaluated the effect of the ingestion of a Jerte Valley cherry-based product, compared to a placebo product, on urine cortisol and 5-hydroxyindoleacetic acid (5-HIAA) levels, and on mood in young, middle-aged, and elderly participants. METHODS Cortisol and 5-HIAA acid levels were measured by commercial enzyme-linked immunosorbent assay kits. The mood state profile was analysed using a visual analogue scale and the state-trait anxiety inventory. RESULTS Our findings showed that the ingestion of the Jerte Valley cherry product decreased urinary cortisol and increased urinary 5-HIAA levels in all the experimental groups. Moreover, the cherry product was able to lessen anxiety status in the middle-aged and elderly participants, and enhanced subjective mood parameters, particularly family relationships in young participants, and frame of mind and fitness in both middle-aged and elderly subjects. CONCLUSIONS The consumption of the Jerte Valley cherry product may protect against stress and act as a mood enhancer by increasing serotonin availability to the organism, particularly with advancing age.

Improvement in protein separation in Barretts esophagus samples using two-dimensional capillary electrophoresis analysis in presence of cyclodextrins as buffer additives

In two-dimensional capillary electrophoresis (2DCE) components are separated based on their size and hydrophobicity. A preliminary run separates analytes in the first capillary based on size (CSE). Following that, fractions are electrokinetically transferred across an interface into a second capillary, where components are further resolved according to hydrophobicity. In order to succeed in this analysis, two orthogonal methods should be selected for the different modes. The transfers from the first to the second capillary must be efficient in order to reduce tailing effects and lost of resolution. We report a new method to improve the resolution with our 2DCE instrumentation using CD doped buffers. When methyl beta cyclodextrin (mbetaCD) is added to the 2DCE interface buffer a stacking effect is described in the transfers from the first to the second dimension. In addition to that, changes in retention times are observed when proteins form complex with CDs helping in the separation. Protein fingerprints were obtained from BE homogenates using this method in presence of methyl beta cyclodextrin (mbetaCD). Within-day and between-day precision has been studied in order to establish the reproducibility of the methodology proposed.

Automatic evaluation and data generation for analytical chemistry instrumental analysis exercises

In general, laboratory activities are costly in terms of time, space, and money. As such, the ability to provide realistically simulated laboratory data that enables students to practice data analysis techniques as a complementary activity would be expected to reduce these costs while opening up very interesting possibilities. In the present work, a novel methodology is presented for design of analytical chemistry instrumental analysis exercises that can be automatically personalized for each student and the results evaluated immediately. The proposed system provides each student with a different set of experimental data generated randomly while satisfying a set of constraints, rather than using data obtained from actual laboratory work. This allows the instructor to provide students with a set of practical problems to complement their regular laboratory work along with the corresponding feedback provided by the systems automatic evaluation process. To this end, the Goodle Grading Management System (GMS), an innovative web-based educational tool for automating the collection and assessment of practical exercises for engineering and scientific courses, was developed. The proposed methodology takes full advantage of the Goodle GMS fusion code architecture. The design of a particular exercise is provided ad hoc by the instructor and requires basic Matlab knowledge. The system has been employed with satisfactory results in several university courses. To demonstrate the automatic evaluation process, three exercises are presented in detail. The first exercise involves a linear regression analysis of data and the calculation of the quality parameters of an instrumental analysis method. The second and third exercises address two different comparison tests, a comparison test of the mean and a t-paired test.

Rapid ultrasensitive chemometrics-fluorescence methodology to quantify fluoroquinolones antibiotics residues in surface water

A sensitive method for the determination of fluoroquinolones in surface waters at trace concentration level is presented. The proposed two-step methodology consists in a solid-phase extraction using C-18 membranes followed measurement of the emission molecular fluorescence spectra over extracted membrane without elution of the analytes. Membrane background signal was removed by the used of chemometrics calculations, in addition chemometrics was as well used for the direct and simultaneous determination of the studied compounds. The method was optimized for the analysis of three fluoroquinolones: enoxacin (ENO), norfloxacin (NOR) and ofloxacin (OFLO). The fluorescence of these compounds increase drastically when they are in the membrane, thus with this method low concentrations are possible to be determined, as the concentration in which these compounds appear in surface water. Limits of detection at the ng•L–1 level were estimated for ENO, NOR and OFLO.

Influence of the industrial processing and the floral origin into the volatile constituents of honeybee-collected pollen

Honeybee-collected pollen constitutes a potential source of energy and proteins for human consumption. The aim of this study was to determinate if the volatile fraction of pollen is affected by the application of industrial treatment processes and by the floral origin. Two process (thermal and freeze-drying) were compared with the fresh product. The volatile composition was investigated by a suitable analytical procedure based on dynamic headspace followed by thermal desorption gas chromatography mass spectrometry. Using this methodology more than 60 volatile compounds were separated in a phenyl-methyl-siloxane 50 m chromatographic column and identified according to their mass spectra, Kovats retention indices and comparison with those of authenticated reference standards. The differences among the studied honeybee pollens, in terms on volatile profile, were studied by means of the analysis of variance and principal component analysis. The volatile profile of fresh pollen is influenced by the floral origin and altered when it is processed, either by thermal and freeze-drying process, but when thermal process was used, compounds as dimethyl sulphyde and furfural, which affect negatively the functional quality, are found. As conclusion, the freeze-drying system could be a good alternative to the traditional thermal drying process.