Antioxidant Activity of Added Phenolic Compounds in Freeze-Dried Microencapsulated Sunflower Oil

This study was aimed at evaluating the effectiveness of phenolic antioxidants with a similar structure but having a different polarity in dried microencapsulated sunflower oil. The antioxidants tested were, on one hand, α-tocopherol and its water soluble analogue, Trolox, and on the other, gallic acid and its ester derivatives, propyl gallate and dodecyl gallate. At a moderate temperature (40 °C), the samples were oxidized under accelerated conditions by using Cu(II) as an oxidation catalyst. The progress of oxidation was followed up over time in the free and encapsulated oil fractions. The peroxide value, the total content of polymers and, when appropriate, the content of α-tocopherol were determined. Quantitative analysis of the total fraction of the non-volatile oxidation products and their distribution in oligomers, dimers and monomers was applied to samples to obtain a complete evaluation of oxidation. Finally, as a complementary measure, the antioxidants were also assessed by direct application of the Rancimat test at 100 °C on the dried microencapsulated oil samples. Results showed that the antioxidants of lower polarity in each series, i.e. tocopherol and dodecyl gallate, were to a great extent the most protective antioxidants. The results obtained by the Rancimat test were consistent with those found during oxidation at moderate temperature. Furthermore, the addition of Cu(II) reduced proportionally the oxidative stability index of the dried microencapsulated samples.     

Effect of Immersion Time in Osmosis and Ultrasound on Papaya Cell Structure during Dehydration

The effect of ultrasound-assisted osmotic dehydration applied at atmospheric pressure for different lengths of time on papaya tissue structure was evaluated. Ultrasound induced the loss of cellular adhesion, formation of large cell interspaces, and light rupture of the cell walls. The changes in the tissue structure caused by ultrasound application increased sugar loss, water loss, and effective water diffusivity. Ultrasound-assisted osmotic dehydration induced a gradual distortion in the shape of the cells, loss of cellular adhesion, and the formation of large channels caused by rupture of the cell walls. The changes caused by the application of osmotic dehydration resulted in high water loss and sugar gain.     

Forecasting airborne pollen concentration time series with neural and neuro-fuzzy models

Forecasting airborne pollen concentrations is one of the most studied topics in aerobiology, due to its crucial application to allergology. The most used tools for this problem are single lineal regressions and autoregressive models (ARIMA). Notwithstanding, few works have used more sophisticated tools based in Artificial Intelligence, as are neural or neuro-fuzzy models. In this work, we applied some of these models to forecast olive pollen concentrations in the atmosphere of Granada (Spain). We first studied the overall performance of the selected models, then considering the data segmented into intervals (low, medium and high concentration), to test how they behave on each interval. Experimental results show an advantage of the neuro-fuzzy models against classical statistical methods, although there is still room for improvement.¹     

Disorder effect in the transmission spectra of a noncompact single layer of dielectric spheres derived from microwave spectroscopy

Single layers of dielectric spheres are an interesting system to study from the fundamental and applied points of view. In this paper we present a systematic study of the influence of structural disorder on the transmission spectra of arrangements of spheres of different compactness. Glass sphere (ε=7) planes were built and their transmission spectra in the microwave range measured. Transmission behavior of this system is highly tolerant to disorder. Even in completely disordered arrangements, there is a highly rejected band with the dips of the spectrum observable. These results suggest that the collective modes of the sphere planes are formed by weakly coupled Mie modes of the individual spheres, and this coupling is governed by the average distance among the spheres. Disorder tolerance allows simpler fabrication procedures where the position of the spheres does not need to be precisely controlled.     

Volatile composition of pomegranates from 9 Spanish cultivars using headspace solid phase microextraction

Fruits of 9 Spanish pomegranate cultivars were analyzed for quality parameters, volatile composition, and sensory profile. Volatile compounds were extracted using headspace solid phase micro-extraction (HS-SPME) and analyzed by gas chromatography-mass spectrometry (GC-MS) and flame ionization detector (GC-FID). Twenty-one compounds were found in the headspace of fresh pomegranate juices, including aldehydes, monoterpenes, and alcohols. The most abundant compounds were hexanal, limonene, trans-2-hexenal, and cis-3-hexenol. Fruits from the cultivars Mollar Elche(ME) ME14, ME1, and ME2 presented the highest values of overall liking by the consumer panel; however, their total volatiles concentration were low compared to the other pomegranate cultivars and their color intensity was intermediate. Overall consumer liking of pomegranate juices was mainly associated with the presence of monoterpenes (α-terpineol); however, high aldehydes (trans-2-hexenal) concentrations were correlated with poor overall consumer liking. Fruits from sour-sweet cultivars (PTO7 and ADO4) could improve the quality of ME pomegranate juices due to their intense color, high monoterpenes concentrations, and their moderate sourness. Practical Application: The information provided in this study proves that sour-sweet pomegranate fruits can be used in the manufacturing of pomegranate juices and will improve the sensory quality and the volatile composition of this product.     

A risk of developing multiple sclerosis following an outbreak of optic neuritis during a mean follow-up of 4.5 years

OBJECTIVE: The current study was designed to determine the risk of developing clinically definite multiple sclerosis (CDMS) after an isolated idiopathic optic neuritis (ON). PATIENTS AND METHODS: We retrospectively studied 28 patients (range from 18-45 years) who presented a unilateral acute ON between 1 st April and 31 st December. We excluded optic neuropathy of other causes, a previous diagnosis of MS or systemic diseases associated with ON. Patients underwent brain MRI, visual evoked potentials (VEPs), somatosensory evoked potentials (SEPs) and brainstem auditory evoked potentials (BAEPs). The mean interval between ON onset and MRI was 3.1 months. 24 patients were treated with corticosteroids in different ways: oral prednisone (14) and intravenous methylprednisolone (10). Mean duration of the follow-up was 4.5 years in 26 patients. RESULTS: Brain MRI detected white matter areas with increased signal in 10 of 25 patients (40%). Eight (30%) had bilateral anormalities on VEP, while SEPs and BAEPs revealed anormalities in one patient (5.5%). Two out 26 patients (7.7%) developed CDMS; one was treated with oral prednisone and the other with intravenous corticosteroids. No patients with normal MRI developed MS compared to 20% of patients with lesions on initial brain MRI. The only patient with abnormal SEPs and BAEPs did not develop MS. CONCLUSIONS: We found in our population low rate of developing CDMS with higher risk for those ON with abnormalities on initial brain MRI.     

Excitatory amino acid receptors and puberty

Glutamate is an important excitatory signal in the hypothalamus for the steroid-mediated preovulatory gonadotropin surge. Steroids may exert this action by regulating glutamate receptor levels or glutamate release, or both. Work in our laboratory found no changes in NMDA and kainate receptor binding in the hypothalamus of castrated or castrated plus steroid-replaced male and female rats. Likewise, we found that NMDA and kainate binding did not change over the onset of puberty in the female rat. A competitive quantitative RT-PCR assay using exogenous internal standards was used to measure NMDAR1, GluR1, and beta-actin mRNAs levels. NMDAR1 and GluR1 expression was examined in the preoptic hypothalamic area and in the medial basal hypothalamus at Postnatal Days 10, 15, 20, 25, 30, 32, 34, 36, 40, and 63. A transient increase in GluR1 mRNA levels in the preoptic hypothalamic area was observed on Day 20, with all other time points showing comparable levels. NMDAR1 levels in the POA and medial basal hypothalamus did not change significantly at any of the time points; in contrast, however, AMPA receptor binding levels were increased in the hypothalamus at the time of puberty in the female rat. Thus, in addition to the previously reported elevation of glutamate release rates in the hypothalamus at the time of puberty, AMPA receptors may also be elevated and play a role in mediating glutamate regulatory effects on the timing of puberty in the female rat.     

Esterification of ethenyl benzene and its derivatives with acetic acid in the presence of perchloric acid as a catalyst

The esterification process of ethenyl benzene and its derivative compounds (p-methyl, p-methoxy, p-chloro, m-methyl, m-nitro and m-chloro, respectively) was carried out with acetic acid and using perchloric acid as a catalyst. From the effects of the variables studied it could be concluded that: the temperature and the catalyst concentration influence positively over the olefin conversion, whereas the initial olefin concentration exert no effect over the same; and that the presence of perchloric salts exerts a different influence, depending on the temperature and on the catalyst concentration. It has been proven that the substituted radicals in the m- or p- positions exert an important influence over the conversion of the studied olefins, presenting growing reactivity in the following order: m-nitro ethenyl benzene, m-chloro ethenyl benzene, p-chloro ethenyl benzene, m-methyl ethenyl benzene, ethenyl benzene, p-methyl ethenyl benzene and p-methoxy ethenyl benzene. Finally, a kinetic and thermodynamic study has been done and the corresponding parameters have been calculated, with an adequate fitting.