Integrating medical knowledge to improve science with a novel, straightforward attitude: the bio-integrative medicine

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Formation and prevention of light-struck taste white wine

Light-struck taste is a defect occurring white wines bottled in clear glass and exposed to light. It is manifested by a loss of color and aroma as a result of the presence of sulfur-like smells [1]. Its appearance is due to the reduction of riboflavin (RF), a high photosensitive compound, and the oxidation of methionine (Met) to give methional which is unstable under light and decomposes to acrolein and methanethiol. Two molecules of the latter compound can yield to dimethyl disulfide [1]. Methanethiol is highly volatile, has a low perception threshold (0.3 to 3 \ub5g/L in wine) and confers rotten eggs-like or cabbage-like aromas. Dimethyl disulfide is less volatile, but the olfactory perception threshold is still low (30 \ub5g/L) and it has an aroma impression of cooked cabbage or onion. Concentrations of RF lower than 80-100 \ub5g/L can decrease the risk of light-struck taste appearance [2]. The wine treatment with charcoal can lead to a depletion of RF in white wine [3], but it can have a detrimental effect on sensory properties of white wine. In order to limit the appearance of the light-struck taste, certain antioxidants (sulfur dioxide and glutathione) and wood tannins (oak, chestnut and galla) were tested in model wine containing RF and Met and exposed to light. The concentrations of these two compounds were monitored as well as the content of volatiles. The RF was completely degraded under light independently to the presence of Met. On the contrary, this amino acid underwent to photodegradation only in presence of RF. The sulfur dioxide limited the appearance of the defect maybe due to the formation of a complex riboflavin-sulfur dioxide making the vitamin less susceptible to the photo-degradation. The molar ratio degraded RF:degraded Met ranged from 1:8 to 1:20, much higher than one previously indicated in literature [1]. As expected, the increasing concentrations of RF led to major levels of sulfur compounds. Similarly, higher amounts of Met strongly affected the formation of volatiles which content increased as Met increased. The wood tannins could exert a protective effect, the galla tannins in particular. In fact, the lowest levels of volatiles, namely methanethiol and dimethyl disulfide, were found when the gallotannins were added. Nevertheless, the volatiles were lower in presence of both chestnut and oak tannins in comparison to the model solution. The content of oxidized phenols could be the main actor against the formation of the light-struck taste since it was the highest into the galla tannins. The oxidized phenols could bind the sulfur compounds and, consequently, they could be reduced back to phenols. The protection of white wine against the appearance of the light-struck taste can be achieved by adding the wood tannins, gallotannins in particular, before bottling. As this defect can appear for higher levels not only of RF, but also of Met, low concentrations of these compounds can also play a protective effect allowing the maintenance of the wine quality during the shelf-life

Key For The Identification Of Mediterranean Brachyuran Megalopae

Based on larval literature, an identification key has been constructed for the megalopae of 55 species of Mediterranean Brachyura. This key is based mainly on external morphological characteristics visible, by using a microscope, limiting the necessity for dissection of specimens. Characteristics used include presence/absence of ornamentation on the carapace, number of abdominal somites, number and position of setae and/or spines on antennula, antenna, pereiopods and structure of uropods, etc. Partial dissection is only required to count the setae on the scaphognathite margin. Using the above characters, it is also possible to gather almost all the families into groups. However, the megalopae of Portunidae as well as those of the three species of Brachynotus genus are similar to each other and their identification at a specific level requires the use of features somehow variable and difficult to count. In the Majidae, the megalopae of 14 species are already known. The complexity of morphological characters typical of this family makes it difficult to define characters common to all spider crab megalopae. Nevertheless, the key may be an aid for carcinology studies, especially those including sorting and identification of megalopae from plankton samples

Application of UV-C light for preventing the light-struck taste in white wine

The light-struck taste is a fault occurring in white wine bottled in clear bottles and exposed to light. The defect is due to the formation of methanethiol and dimethyl sulphide responsible for like-cabbage aroma arising from the reaction between riboflavin (RF), a highly light-sensitive compound, and methionine (Met). The light-struck taste is limited for RF concentration lower than 50 \ub5g/L achieved through the choice of a Saccharomyces strain low RF-producer and the RF removal with charcoal and bentonite as fining agents [1]. Moreover, the protective effect of wood tannins has been recently showed, especially galla tannins [2]. Due to the RF sensibility to light, the UV-C light treatment was assayed. A synthetic wine solution spiked with RF (200 \ub5g/L) and Met (3 mg/L) was irradiated with UV-C light up to 2000 J/L and RF decay was monitored. A linear decrease as UV-C light intensity increase was observed. RF was lower than 50 \ub5g/L and 20 \ub5g/L for 1500 J/L and 2000 J/L treatments, respectively. The addition of tannins (40 mg/L) led to a limited RF decrease (73%) maybe due to their shading properties [3]. Even though the UV-C light treatment is not admitted by the International Organization of Vine and Wine, its application could represent a tool for avoid the risk of light-struck taste development in bottled wine. The light exposure when the redox potential is high and the combined use of tannins could limit the appearance of this fault after the wine bottling preserving the wine quality during the shelf-life

Manipulation and Generation of Supercurrent in Out-of-Equilibrium Josephson Tunnel Nanojunctions

We demonstrate experimentally manipulation of supercurrent in Al-AlO_x-Ti Josephson tunnel junctions by injecting quasiparticles in a Ti island from two additional tunnel-coupled Al superconducting reservoirs. Both supercurrent enhancement and quenching with respect to equilibrium are achieved. We demonstrate cooling of the Ti line by quasiparticle injection from the normal state deep into the superconducting phase. A model based on heat transport and non-monotonic current-voltage characteristic of a Josephson junction satisfactorily accounts for our findings.Comment: 4 pages, 4 colour figures, published versio

NMR approach for monitoring the photo-degradation of riboflavin and methionine

The light exposure of white wine is responsible for several reactions leading to changes on colour, flavours and, consequently, affecting the sensory profile. These reactions can take place when the white wine is bottled in clear glass and their mechanisms are dependent on both light exposure and chemical composition of white wine. Particular attention has been given to the reaction involving riboflavin (RF), a photo-sensitizer compound, and methionine (Met), a sulfur-containing amino acid, that can cause the formation of volatile sulphur compounds (VSCs), namely methanethiol and dimethyl disulfide. These compounds are responsible for a defect known as light-struck taste. Previous studies showed that hydrolysable tannins, in particular those from nut galls, limited both the degradation of Met and the formation of VSCs. The effectiveness of hydrolysable tannins was also proved after light exposure and storage for 24 months. In order to better understand the role of tannins in the photo-degradative reactions, an NMR approach was carried out. A solution containing RF (0.2 mM) and Met (2 mM) acidified at pH 3.2 was exposed to light by using fluorescence light bulbs. The solution was exposed to light up to two hours sampling it every 15 minutes. The same experimental conditions were applied in presence of gallic acid (2 mM), a constitutive unit of nut gall tannins. The degradation of RF and Met was monitored and, as expected, their signals decreased as the light exposure increased. Results provided evidence that a new signal appeared at 2.64 ppm. This signal was assigned to the SOCH3 moiety of methionine sulfoxide through the addition of the standard solution and standard 2D-NMR assignment techniques. The formation kinetic of methionine sulfoxide was measured for increased duration of light exposure and its rate resulted two-folds lower with the addition of gallic acid. This result suggests that the limited degradation of Met in presence of tannins, also observed in previous studies, is due to their action as competitor with Met in reducing RF from its excited form. The NMR technique was suitable for monitoring the photo-degradative reaction of RF and Met. Further researches have been carried out in order to verify and prove the ability of tannins in quenching both singlet oxygen and RF

Impact of Cooking on Bioactive Compounds and Antioxidant Activity of Pigmented Rice Cultivars

Pigmented rice cultivars, namely Venere and Artemide, are a source of bioactive molecules, in particular phenolics, including anthocyanins, exerting a positive effect on cardiovascular systems thanks also to their antioxidant capacity. This study aimed to determine the total phenol index (TPI), total flavonoids (TF), total anthocyanins (TA) and in vitro antioxidant capacity in 12 batches of Venere cultivar and two batches of Artemide cultivar. The rice was cooked using different methods (boiling, microwave, pressure cooker, water bath, rice cooker) with the purpose to individuate the procedure limiting the loss of bioactive compounds. TPI, TF and TA were spectrophotometrically determined in both raw and cooked rice samples. Rice samples of Artemide cultivars were richer in TPI (17.7-18.8 vs. 8.2-11.9 g gallic acid/kg in Venere rice), TF (13.1 vs. 5.0-7.1 g catechin/kg rice for Venere rice) and TA (3.2-3.4 vs. 1.8-2.9 g Cy-3glc/kg for Venere rice) in comparison to those of Venere cultivar; as well, they showed higher antioxidant capacity (46.6-47.8 vs. 14.4-31.9 mM Trolox/kg for Venere rice). Among the investigated cooking methods, the rice cooker and the water bath led to lower and comparable losses of phenolics. Interestingly, the cooking water remaining after cooking with the rice cooker was rich in phenolics. The consumption of a portion of rice (100 g) cooked with the rice cooker with its own cooking water can supply 240 mg catechin and 711 mg cyanidin 3-O-glucoside for Venere rice and 545 mg catechin and 614 mg cyanidin 3-O-glucoside for Artemide rice, with a potential positive effect on health

Development of a HPLC method for the simultaneous analysis of riboflavin and other flavin compounds in liquid milk and milk products

A high-performance liquid chromatography method with fluorescence detection was developed for the quantification of riboflavin (RF), flavin mononucleotide (FMN), flavin adenine dinucleotide (FAD) and their photodegradation products, lumichrome (LC) and lumiflavin (LF), in liquid milk and milk products. Both sample preparation and chromatographic separation were studied to avoid acidic conditions that proved to affect flavin stability and degrade FAD into FMN. The sample preparation includes centrifugal skimming and ultrafiltration steps and is suitable for routine application. Linear response was obtained for individual flavins in the respective concentration ranges of interest and relative standard deviation (RSD) was lower than 5%, except for FAD (RSD 11%). The recovery ranged between 80\u2013100%. The proposed method proved to be suitable for assessing flavins in commercial liquid milk and fermented milk products, and for monitoring the degradation of FAD, FMN and RF and the formation of LF and LC in bottled milk exposed to light during shelf storage

Saccades and smooth pursuit eye movements in central vertigo

In order to analyze the diagnostic efficiency of saccadic and pursuit eye movements compared to findings from brain magnetic resonance imaging in patients with central vertigo, 108 patients were selected from 580 dizzy patients as cases of suspected central origin; the saccadic and pursuit eye movements were evaluated by electronystagmography and findings were compared to information from magnetic resonance imaging. The study of oculomotor movements in patients suspected of having a central lesion revealed a 83.3% sensitivity and 21.2% specificity. Restricting consideration to severe alterations in eye movements as indicative of a central origin, this test gives a 71.4% sensitivity and 50.0% specificity. In conclusion, the study of alterations in oculomotor movements, in patients with suspected central lesions, proved to be a test with good sensitivity also compared with results of magnetic resonance imaging

Melatonin and its derivatives in red wine: contribution of fermenting microorganisms

Melatonin (MEL) is an indoleamine produced mainly by the pineal gland in vertebrates and it has a significant role in regulation of circadian rhythm, mitigation of sleeping disorder and jet lag. It has been found in medicinal plants, plant foods including seeds, fruits and fermented beverages, and, therefore, its occurrence in plants is now ascertained. In grapes and wines, MEL ranges from sub-ng/g to \ub5g/g and from sub-ng/mL to ng/mL, respectively, with varying levels according to both endogenous and exogenous factors. In addition, MEL isomers and tryptophan-ethylester (TEE, a compound with the same molecular weight of MEL) have recently been detected in wine and the fermenting yeast plays an important role for their production [1]. It has been suggested that, in synergy with polyphenols, MEL in wine may contribute to maximize the health-promoting effects of Mediterranean diet. The research aimed to validate an analytical method for the simultaneous detection of MEL, TEE and tryptophan. The sample preparation was developed by means of SPE purification. Purified samples of synthetic wine solution (tartaric acid 5 g/L, ethanol 12% [v/v], pH 3.2) and red wine spiked with the analytes of interest were analyzed by liquid chromatography coupled with both fluorescence and mass spectrometry detectors. MEL, TEE and tryptophan were successfully detected and quantified by both the analytical conditions adopted. The response was linear for all the investigated compounds and it was comparable between synthetic wine solution and red wine. The recovery was higher than 85% and the relative standard deviation was lower than 10%. The developed method was applied for the analysis of red wine samples produced in a cold area of North of Italy. Preliminary results showed an increase of TEE concentrations suggesting the possible positive influence of secondary fermentations other than the alcoholic fermentation