Valentín Pando

Improving gluten-free bread quality by enrichment with acidic food additives

An experimental design has been developed to improve gluten-free bread formulation, on the basis of rice flour and hydroxypropylmethylcellulose (HPMC) as alternative baking ingredients. In order to improve the quality of gluten-free bread, several levels of acidic food additives (acetic acid, lactic acid, citric acid and monosodium phosphate) have been tested. The influence of these compounds on the dough and on bread properties has been determined, including a hedonic sensory test of appearance, odour, taste and texture of bread. Results suggest that monosodium phosphate yields bread producing better texture scores, associated with the highest volumes of the loaf. Discussions are made on the basis of CO2 transport pathway across the HPMC network and simultaneous interactions with acidic food additives present. Chemical properties of the acids justify the breads alveolus size and the preservative effects of acetic acid in the dough.

Maximizing profits in an inventory model with both demand rate and holding cost per unit time dependent on the stock level

We study an EOQ inventory model with demand rate and holding cost rate per unit time, both potentially dependent on the stock level. The ordering cost, the holding cost and the gross profit from the sale of the item are considered. The objective is to maximize the average profit per unit time. We present the analytical formulation of the problem and demonstrate the existence and uniqueness of the optimal cycle time, giving a numerical algorithm to obtain it. Moreover, we provide two fundamental theoretical results: a rule to check when a given cycle time is the optimal policy, and a necessary and sufficient condition for the profitability of the system. Several EOQ models analyzed by other authors are particular cases of the one here studied. We present some numerical examples to illustrate the proposed algorithm and analyze the sensitivity of the optimal solution with respect to changes in various parameters of the system.

Carbon in heartwood, sapwood and bark along the stem profile in three Mediterranean Pinus species

Abstract• ContextUnderstanding biological processes in forests is necessary to orientate ecosystem management towards potential C sequestration. To achieve this, information is required about changes in forest biomass C pools, including the stem components (bark, sapwood and heartwood).• AimsThis study aimed to determine whether there are differences in C concentration in axial and radial directions within stem biomass in Pinus nigra, Pinus pinaster and Pinus sylvestris.• MethodsWood samples from a permanent plantation in northern Spain were examined for C concentration and wood bulk density. • Results The results showed that C concentration was higher in heartwood than in sapwood in the three species. Pinus spp. sapwood C concentration increased along the stem, while the C concentration in heartwood tissue showed the opposite behavior. In bark, Pinus pinaster showed a decreasing trend, in contrast to Pinus nigra and Pinus sylvestris, where higher values were found at the base and top of the stem. Finally, wood bulk density decreased in heartwood, sapwood and bark areas when stem height increased. Estimating C content taking into account different anatomical parts and heights is important in considering the specificity of the different parts because of their potential commercial or ecological use in forest ecosystems.

Effect of nut paste enrichment on physical characteristics and consumer acceptability of bread

Four kinds of nut paste (almond, hazelnut, peanut, walnut) in three different percentages (5, 10, and 15%) were added to bread formula to study the morphogeometric and textural characteristics, and the consumer acceptability of enriched breads. The change of texture along time was also studied. Control bread presented the lowest volume, water loss and height, and the highest firmness and chewiness. The enrichment with 15% of nut paste caused a decrease in loaf volume, weight loss, cohesiveness, and resilience but an increase in height, firmness, and chewiness. Almond and walnut breads presented the lowest values in firmness and chewiness. The lowest cohesiveness and resilience corresponded to hazelnut bread. The increased firmness during storage was slower in enriched than in nonenriched breads. The adhesiveness, cohesiveness, and resilience decreases were more important in the first 2 days of storage. Breads added with 10 and 15% nut paste showed the highest intent for consumption, persistence, and texture values. Peanut-enriched bread was the least accepted bread. Only a third of the consumers were able to correctly identify the nuts added.

Characterization of honeys by melissopalynology and statistical analysis

We analyzed pollen from 89 honey samples, collected in Leon and Palencia provinces (NW Spain). According to their pollen spectra, 46 were considered monofloral. The most abundant monofloral honeys were Erica types followed by Castanea, Centaurea, Reseda and Helianthus. One hundred and forty-two different pollen types were recorded, belonging to 47 families. Fifty-five of them reached percentages over 3% in at least one sample, while the other 87 types never exceeded 3% in any of the 89 samples. The families that were present in the highest number of samples were Fabaceae, Rosaceae, Cistaceae and Asteraceae. Plant families that had the highest percentages were Fabaceae, Ericaceae, Asteraceae, and Rosaceae. The pollen types that appeared in most samples were Rubus ulmifolius (73 samples), Cytisus scoparius (70) and Mentha aquatica (62); the pollen types that had the highest relative abundance were Erica arborea, Lotus corniculatus, Cytisus scoparius. The pollen types of the Ericaceae family, Jasione montana...

Optimal policy for profit maximising in an EOQ model under non-linear holding cost and stock-dependent demand rate

In this article, we integrate a non-linear holding cost with a stock-dependent demand rate in a maximising profit per unit time model, extending several inventory models studied by other authors. After giving the mathematical formulation of the inventory system, we prove the existence and uniqueness of the optimal policy. Relying on this result, we can obtain the optimal solution using different numerical algorithms. Moreover, we provide a necessary and sufficient condition to determine whether a system is profitable, and we establish a rule to check when a given order quantity is the optimal lot size of the inventory model. The results are illustrated through numerical examples and the sensitivity of the optimal solution with respect to changes in some values of the parameters is assessed.

A Comparison of Isozyme and Morphological Markers to Assess the Within Population Variation in Small Populations of European aspen (Populus tremula L.) in Spain

Summary European aspen (Populus tremula L.) has been traditionally thought to establish new stands by vegetative propagation through root suckers produced by very few individuals (often only one). Morphological traits and isozyme patterns were studied in five small stands in northern Spain. Both isozyme and morphological approaches showed variation within and between stands. Estimated intrapopulational variation was higher than the expected, and clusters of individuals with the same isozyme multilocus patterns within each population have been identified. In order to check to what extent morphological markers are affected by the genotypes or clones, comparisons between leaf parameters and isozyme patterns were performed by hierarchical ANOVA and tests of hypothesis were constructed from the components of variance. Leaf shape parameters show a good correlation with the isozyme multilocus patterns. On the other hand, leaf size parameters, were more influenced by environmental factors. These traits may be useful as tools for the definition of in situ conservation units in endangered European aspen stands.

Investigation and correction of the interference of ethanol, sugar and phenols on dissolved oxygen measurement in wine

The dissolved oxygen in wine is routinely measured to control and monitor various oenological processes. The availability of devices based on different technologies and features allows a user to select a device that best meets their needs. However, grape must and wine samples each exhibit a complex composition that varies with time, which, along with atmospheric conditions, makes it necessary to evaluate the effects of these factors on dissolved oxygen measurements. This work evaluates the effects that ethanol, sugar, and phenols have on dissolved oxygen measurements in a model and real wine. The results suggest that significant errors are made in all studied systems and that the response of each device is different. Therefore, a compensation value was developed to take into account the sample composition. A compensation value was proposed to minimise the error made by each device based on the ethanol and sugar contents of the measured liquid. The best results are those obtained after using the compensation value to correct the data from the Pyro-Mini device. In all cases, errors made in DO measurements by optical systems were reduced by 50-82% by applying the compensation value for synthetic wines and 45-100% for real wines.

Modelling coarse woody debris in Pinus spp. plantations. A case study in Northern Spain

Abstract• Coarse woody debris (CWD) plays a substantial role in several ecological processes in forest ecosystems, providing a habitat for many organisms and participating in biogeochemical fluxes. Understanding CWD dynamics is important to classify adequate density, size and amount into different decay classes and to make decisions that include biodiversity and the carbon budget in practical forestry.• A two-step model has been developed to quantify CWD in Pinus spp. plantations in Northern Spain. The two-step approach was composed of a logistic model to predict the probability of CWD occurrence and linear models to quantify the two components considered, basal area of snags and volume of logs.• Site conditions, and climatic and stand variables were included in the models as independent variables. Good performance of the two-step model (R2snag = 39.9%, R2log = 62.8%) was observed.• Modelling CWD is a useful tool for simulating future scenarios in the current context of climate change. Models inform stakeholders properly about defining the best silvicultural options for the distribution of CWD under sustainable forest management.

Influencia de la densidad del arbolado sobre el desfronde y su reciclado en pinares de repoblación del norte de España

El objetivo del presente trabajo fue estudiar las dinamicas de desfronde y descomposicion de aciculas en plantaciones de Pinus halepensis y Pinus sylvestris de Castilla y Leon (Espana) asi como el efecto de la densidad de las masas sobre dichos parametros. Para ello se seleccionaron cuatro rodales de cada una de las especies estudiadas y en cada uno de ellos se establecieron ocho parcelas considerando un gradiente de areas basimetricas, estudiandose un total de 32 parcelas. En el centro de cada parcela se situo una trampa de desfronde y 15 bolsas de descomposicion. El desfronde contenido en las trampas se recogio mensualmente. Trimestralmente se retiro una bolsa de descomposicion de cada parcela. Se determino el peso seco de desfronde separado en las distintas fracciones asi como la perdida de peso de las bolsas de descomposicion a lo largo del tiempo. Finalmente se estudio la relacion existente entre el area basimetrica local de las parcelas y los parametros antes descritos. Se constato la existencia de diferencias significativas en las cantidades de desfronde y en la tasa de descomposicion de las aciculas contenidas en las bolsas en funcion del area basimetrica de la parcela.