Optimization of the Aqueous Decoction Process of Combretum micranthum Leaves

This work proposes to compare the extraction of total polyphenols and the coloring obtained after several series of decoction at 100°C/20min, of whole or crushed leaves of Combretum micranthum. The total phenolic content of the extracts obtained after decoction was determined by Folin’s method. The color parameters were measured using a colorimeter based on the CIELAB system. The analysis of variance (ANOVA) shows significant differences (p 0.05) on different parameters evaluated. The Minitab 19 software was used to classify the extracts according to the color parameters (L, A, and B). The results showed that the maximum of polyphenols (21.67%) was extracted in the crushed leaves after three series of decoctions while with the whole leaves the maximum of 16.17% is obtained after six series of decoctions. The concentration of total polyphenols becomes low from four series of decoctions with 0.146 g·AG·100 g-1 MS. The red and yellow coloring drops respectively by 85 and 69% with crushed leaves and 64 and 21% with whole leaves. The conductivity and the brix of the extracts fall according to the series of decoctions. These results show that for optimal use of C. micranthum leaves in traditional medicine, crushed leaves and three series of decoctions are indicated and sufficient.

Effect of Sodium Carbonate on Extraction by Aqueous Decoction of Total Polyphenols from Crushed and Whole Leaves of Combretum micranthum

Sodium bicarbonate is sometimes used to aid in the extraction of total polyphenols. Its main effect is to increase the pH of the extraction solution. Raising the pH can cause changes in the chemical structure of polyphenols. This can lead to variations in their biological properties, solubility and stability. This work studied the effect of sodium carbonate on the extraction by aqueous decoction of total polyphenols from the leaves of Combretum micranthum. The content of total phenolic compounds in the extracts was estimated by the Folin-Ciocalteu method. The color of the samples was measured using a colorimeter (type: KONICA MINOLTA. Japan) based on the CIELAB color system. The results obtained were subjected to a one-way ANOVA analysis of variance with R software version 3.2.4 Revised (2018) and Minitab-18 software. The results reveal a drop in the concentration of extracted polyphenols proportional to the addition of sodium carbonate, i.e. a drop from 3.30 to 1.04 mg·AG·100 g-1 of extract on whole leaves and 3.921 to 2.551 mg·AG·100 g-1 extract on crushed leaves. On the other hand, the intensity of the coloring of the extracts increases significantly with the addition of sodium carbonate from 0.0 g·L -1 to 0.666 g·L-1.

Assessing the Crop Growing Period According to the Climate Change Forecasts for Marina Baixa (SE Spain)

The present work aims to assess the likely effects of climate change on the length of growing period (LGP) of crops in Marina Baixa (SE, Spain). LGP can be assessed by a balance between preci- pitation and reference evapotranspiration. Less rainfall and an increased evapotranspiration, forecast by Global Climate Models (GCMs), are considered as a high risk for agriculture. This area is located in a semiarid climate region where water is a very limited resource. It is a typical example of areas where the agricultural sector has to compete for water with the tourism industry. In this context, by using observed and projected precipitation data set (model HadCM3, Scenario A2), calculating reference evapotranspiration (ETo), and applying the frequency analysis of a probability-type method, we estimated the growing period length in the observed period (1961-1990) and three 30-year future periods (2011-40, 2041-70 and 2071-99) in the study area. The results show a drop in annual precipitations (&#45?30%) and an increased ETo (+18%) towards the end of this century with respect to the observed period (mean annual rainfall: 356 mm;mean ETo: 1476 mm). The results also show a decrease in the number of decades (10 days) when precipitation exceeds half of the ETo, which means shorter growing periods as the 21st century advances. This expected reduction in growing period length towards the end of the present century will imply that many rainfed crops, like olives, almonds and cereals, will require a higher irrigation water supply to maintain suitable growth and performance levels. The results are an early warning to manage water resources in Marina Baixa in a sustainable way.

Effects of Seed Pretreatment on Germination, Growth and Yield of <i>Momordica charantia</i>L.

Momordica charantia is a plant species widely used in food and traditional medicine. However, the germination techniques and the performances of M. charantia are poorly understood by the populations. This study aims to better understand the germination, growth and development characteristics, and yield of M. charantia. Three pretreatments of the seeds are used for the shortening of the pre-germination period: soaking the seeds in tap water for 24 hours (batch 2), in hot water at 80˚C (batch 3), for 24 hours and in the boiling water at 100˚C for 24 hours (batch 4). A control without soaking (batch 1) was also carried out. The seeds were sown in plastic boxes in the laboratory with sterile sand and directly in the nursery in polyethylene sleeves. The influence of the light factor (light and dark) and watering frequency (every day and every two days) on the growth and yield parameters was evaluated respectively in the laboratory and in the nursery. Germination, growth and yield parameters were determined. The results show that the light and frequency of watering factors have no influence (p > 0.05) on the rate and duration of seed germination unlike pretreatments. Thus, Batch1 and 2 exhibit significantly higher germination rates (70% ± 16%) than Lots 3 and 4 (21% ± 15%) in the laboratory and in the nursery. On the other hand in terms of germination time, batch 3 and 4 displayed shorter durations (14 days) than those batch1 and 2 (23 days). Growth parameters and yield (fruit and seeds) are strongly influenced by watering frequency, unlike pretreatments which only affect yield. Growth and yield parameters are significantly higher with daily watering than daily watering. Ultimately, this study showed that pretreatments have an influence on the duration and rate of germination as well as the frequency of watering on the performance of M. charantia.

Impact of Storage Conditions on the Physicochemical Characteristics of Baobab (Adansonia digitata L.) Seed Oil

The evolution of some quality markers of baobab (Adansonia digitata L.) was studied. Baobab oil extracted by pressing was packaged in 30 mL non-amber glass bottles and stored at different temperatures: 20°C, 30°C and 45°C. The physicochemical parameters (acid, peroxide, iodine, saponification, refraction and color indices) were determined during three months’ storage. A significant 5% increase in acid, peroxide and saponification value was observed over time. However, the iodine value decreased. The yellowing and refractive index remained stable while storage at 45°C caused the most significant changes in chemical parameters. The results obtained show that oils stored at 20°C had the lowest acid (2.42 ± 0.26 mg KOH/g) and peroxide (0.82 ± 0.25 mEqO2/Kg) value after three months of follow-up.