The Quality Evaluation of Avocado Fruits (Persea americana Mill.) of Hass Produced in Different Localities on the Island of Tenerife, Spain.

The effect of the production area on the quality of Hass avocados grown on the island of Tenerife was studied. For this purpose, several physicochemical parameters, such as fruit weight, percentage of pulp, seed and skin, proximate composition, minerals, total phenolic compounds (TP), total flavonoid compounds (TF), α-tocopherol, antioxidant capacity, and fatty acid profile were analyzed. The location of the orchards significantly influenced avocado weight; pulp and seed percentage; and fat, fiber, ash, α-tocopherol, TP, phosphorus, potassium, calcium, iron, zinc, and oleic and palmitoleic acid contents. Buenavista (BU) avocados were the smallest (185 g) and presented the highest percentage of pulp (77.1%) and lowest percentage of fiber (5.43%). The highest levels of dry matter (33.8%) and fat (20.4%) were found in avocados harvested in Los Silos (SI) and Santiago del Teide (SA), respectively. Compared with those at the other locations, the avocados harvested in Güímar (GU) had high levels of α-tocopherol (52.2 µg g-1) and phenolic compounds (56.0 mg GAE 100 g-1). Avocados from Los Realejos (RE) had the highest percentage of oleic acid and the lowest percentage of palmitoleic acid. Numerous significant correlations were found between the variables studied, especially those between TP, TF, and antioxidant capacity (DPPH) and between fat percentage and dry matter.

The chemical composition of barley grain (Hordeum vulgare L.) landraces from the Canary Islands.

The proximate composition, total phenolics, antioxidant activity, minerals, and trace elements were determined in 42 barley landraces in order to highlight their nutritional potential and promote their cultivation. Two-row barley landraces had a higher average content of starch, protein, total phenolic compounds, and iron, when compared with six-row ones that presented higher mean ash and fiber concentrations. Additionally, the six-row barley landraces with strongly pigmented grains had lower zinc and manganese and higher protein mean concentrations than the whitish or lightly pigmented barley landraces. Factor analysis and linear discriminant analysis were used to correctly differentiate samples according to type of barley (landrace or commercial) and number of rows. In general, all the parameters varied considerably among the barley landraces analyzed, but some barley landraces could be emphasized according to fiber, minerals, and phenolic antioxidants. There were important differences in the mean values in all the chemical parameters according to the island of origin of the barley grains. The application of linear discriminant analysis was also a useful tool to differentiate all the barley landraces with six rows according to the island of origin. PRACTICAL APPLICATION: Barley is a versatile cereal that can be used for human and animal feed, brewing, and as biodiesel. From the nutritional point of view, barley is rich in starch, protein, dietary fiber and minerals, as well as antioxidant compounds and vitamins. The landraces analyzed in this study have remained intact for the last 900 years, which gives opportunity to genome of these barley landraces to evolve some very specific traits. The physicochemical characterization of these local landraces carried out by us could be very useful as a source of new quality in breeding programs.

Physicochemical characteristics and pollen spectrum of monofloral honeys from Tenerife, Spain.

Physicochemical parameters, sugar composition and botanical origin were determined in four monofloral honeys, chestnut, fennel, tajinaste, and Teide broom honeys, abundantly produced in Tenerife Island. All the parameters were within the established intervals in Europe for each type of honey. Large differences between the four monofloral honeys were observed, being the chestnut honeys with most of differential characteristics. Linear discriminant analysis on the physicochemical parameters and sugar composition allows to distinguishing the four types of honeys analysed.

Xanthohumol, a prenylated flavonoid from hops (Humulus lupulus L.), protects rat tissues against oxidative damage after acute ethanol administration.

Ethanol-mediated free radical generation is directly involved in alcoholic liver disease. In addition, chronic alcohol bingeing also induces pathological changes and dysfunction in multi-organs. In the present study, the protective effect of xanthohumol (XN) on ethanol-induced damage was evaluated by determining antioxidative parameters and stress oxidative markers in liver, kidney, lung, heart and brain of rats. An acute treatment (4 g/kg b.w.) of ethanol resulted in the depletion of superoxide dismutase, catalase and glutathione S-transferase activities and reduced glutathione content. This effect was accompanied by the increased activity of tissue damage marker enzymes (glutamate oxaloacetate transaminase, glutamate pyruvate transaminase and lactate dehydrogenase) and a significant increase in lipid peroxidation and hydrogen peroxide concentrations. Pre-treatment with XN protected rat tissues from ethanol-induced oxidative imbalance and partially mitigated the levels to nearly normal levels in all tissues checked. This effect was dose dependent, suggesting that XN reduces stress oxidative and protects rat tissues from alcohol-induced injury.

Spectroscopic study of the interaction between lycopene and bovine serum albumin.

The interaction of lycopene with bovine serum albumin (BSA) in aqueous solution was studied by fluorescence quenching, three-dimensional fluorescence and circular dichroism spectroscopy. The data showed that the fluorescence of BSA was quenched by lycopene at different temperatures through a dynamic mechanism. The evaluation of three-dimensional fluorescence spectra revealed a conformational modification of BSA induced by coupling with lycopene and an increase in protein diameter as a consequence of the ligand-protein interaction. Moreover, the information obtained from evaluation of the effect of lycopene on BSA conformation by circular dichroism strongly supported the existence of a slight unfolding of BSA induced by coupling to lycopene.

Xanthohumol prevents carbon tetrachloride-induced acute liver injury in rats.

Xanthohumol (XN), a prenyl flavonoid present in beer, prevents the acute hepatic injury induced by carbon tetrachloride (CCl4) in rats. Pre-treatment of rats with XN significantly reduced the increased liver weight observed in CCl4-intoxicated rats, normalised the increased values of plasma lactate dehydrogenase, glutamate oxaloacetate transaminase and glutamate pyruvate transaminase activities and reduced the incidence of histopathological alterations produced by CCl4. The oxidative stress induced by CCl4 administration elicited a significant decrease in the levels of reduced glutathione as well as an increase in thiobarbituric acid reactive substances (TBARS) and H2O2 concentrations. Pre-treatment of rats with XN resulted in a significant (p<0.05) increase in reduced glutathione (GSH) content and a reduction in TBARS and H2O2 concentrations to their normal values. XN pre-treatment also prevented the significant reductions of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glutathione S-transferase activities observed in CCl4-treated rats compared to control animals. Our results suggest that the hepatoprotective effect of XN is based on its antioxidant properties as well as it being an efficient inhibitor of lipid peroxidation and a protector against the degradation of antioxidant enzymes induced by CCl4 intoxication.

Cluster analysis and artificial neural networks multivariate classification of onion varieties.

Eight cultivars of different colored onions (white, golden, and red) were evaluated for fresh bulbs cultivated and grown under the same environmental and agronomical conditions. Cluster analysis and principal component analysis, based on different flavonoids, total phenols, and pungency, data showed that the onions were not clustered according to variety (genetic similarity degree), whereas the color was the variable with the highest influence, ranging between 50 and 70%. Artificial neural networks were applied to study the possibility of discriminating among onion varieties. Characterization of the onion according to variety and procedence of the seeds was around 95-100%. Samples belonging to the Carrizal Alto procedence had an incorrect classification for 25% of the data.

Influence of the cultivar on the organic acid and sugar composition of potatoes.

BACKGROUND: Citric, malic, tartaric, oxalic, ascorbic, aconitic and fumaric acids, and sucrose, fructose and glucose, were determined in ten potato cultivars (Azucena negra, Bonita, Bonita negra, Borralla, Colorada de baga, Mora, Negra, Palmera lagarteada, Peluca blanca and Terrenta) from the Canary Islands in order to differentiate them. The influence of the production zone was also considered. RESULTS: Citric acid and sucrose were the most abundant organic acid and sugar, respectively. There were significant differences in all the analysed sugars and organic acids between the potato cultivars, except for oxalic and malic acids. Differences associated with the production zone were found in the contents of organic acids for some cultivars. Linear discriminant analysis is a useful tool to differentiate the potato samples according to the cultivar and the zone of production. CONCLUSIONS: Seven organic acids (citric, oxalic, malic, tartaric, aconitic, fumaric, and ascorbic acids) were identified and quantified in potatoes. The main sugars (sucrose, glucose and fructose) were also determined. The genetic information of the cultivars determines marked differences in sugars and organic acid contents among the analysed potato cultivars. The soil and climatic conditions affect the organic acid and sugar contents of some potato cultivars.

Organic acid contents in onion cultivars (Allium cepa L.).

The following organic acids (glutamic, oxalic, pyruvic, malic, tartaric, citric, and fumaric), pungency, Brix degree, acidity, and pH were determined in onion cultivars (Texas, Guayonje, San Juan de la Rambla, Carrizal Alto, Carrizal Bajo, and Masca) harvested in the same agroclimatic conditions. Glutamic acid was the most abundant organic acid (325 +/- 133 mg/100 g) followed by citric acid (48.5 +/- 24.1 mg/100 g) and malic acid (43.6 +/- 10.4 mg/100 g). There were significant differences between the onion cultivars in the mean concentrations of all of the analyzed parameters. The San Juan de la Rambla and Masca cultivars presented, in general, higher concentrations of the organic acids than the other cultivars. Significant differences in most of the analyzed parameters were observed between the two seed origins for the Masca and San Juan de la Rambla cultivars. The onion samples tended to be classified according to the cultivar and, in the case of San Juan de la Rambla cultivar, according to the precedence of the seeds after applying discriminant analysis.