Optimization of a Tiger Nut-Based Yoghurt Formulation by Response Surface Methodology

Tiger nut is a comestible tuber which offers many under products such as yoghurt. The parameters influencing the quality of yoghurt being numerous, response surface methodology was used to optimize the formulation in order to reach a low intake of milk powder. The volume of tiger nut milk, mass milk powder and sugar mass are the factors monitored while the titratable acidity (AT), pH, dry soluble extract (ESS), ash, viscosity and color are the expected responses in these tests. The data are processed with a degree of confidence p < 0.05 associated with statistical analysis by the software Statgraphic Centurion XVI version 16.2.04. The different tests show that the factors have overall significant effects (p < 0.05) on the acidity, the ashes and the Whiteness index. The linear and quadratic factors of tiger nuts milk as well as those linears of the milk powder have significant effects (p < 0.05) on the pH and the ashes. The linear factors of milk powder have significant effects on DSE, AT and pH. The optimal formulation yielded a volume of tiger nut milk equal to 3.7 L/kg, a mass of powder milk of 63.4 g and 75 g of sugar for one kilogram of yogurt. With a desirability of 75%, this model is apt to explain the results and the experimental values fit with the predicted ones and are within the norms. The proximate analysis of optimal yoghurt formulation shows that fat and proteins contents are respectively 5.67% and 2.2%. Calcium, magnesium and potassium contents are respectively 160, 40 and 180 mg in 100 g of yoghurt.

Nutritional Potential of Two Leafy Vegetables <i>Leptadenia hastata</i>Decne and <i>Senna obtusifolia</i>Link Consumed in Senegal

This study focused on two woody leafy vegetables Leptadenia hastata Decne and Senna obtusifolia Link, commonly consumed in Senegal. Leaves were col-lected from three regions. Then, proximate analyses and micronutrients were carried out to evaluate their nutritional values. Results revealed that protein level of S. obtusifolia (SO) is richer (21.75%) than Leptadenia hastata (LH) (18.16%). The cellulose and carbohydrate contents of the two vegetable’s leaves are in the same order except those of LH from Widou which are less rich in cellulose (8.31%) and richest in carbohydrate (6.35%). These leaves are also good sources of various mineral elements and especially iron. Leaves of LH appear to be richer in iron and magnesium, while SO appears to be richer in calcium. Vitamin C intakes of SO leaves are better than those of LH and respectively range from 142 to 196.5 and 22.5 to 159.5 mg/100 g. According to the use of this leafy vegetable by the populations, a domestication opportunity is thus justified to ensure availability and accessibility of these significant sources of micronutrients.

Process Diagnosis and Aging Effects on a Traditional Millet-Based Drink: <i>Boumkaye</i>

Boumkaye is a traditional fermented millet-based drink (Pennisetum glaucum L.) produced in Casamance (region in Senegal). Unknown and circumcised beverage, it has therapeutic properties due to aqueous creeper extracts from Abrus pulchellus plant and naturally present during the process. The objective of this work was to investigate the fabrication process of a millet-based beverage as an alternative source of nutrients. The diagnosis of beverage production by monitoring its physical and chemical parameters during two months of storage at room temperature was studied. The established manufacturing process, composed by a production of aqueous extracts after maceration of the Abrus pulchellus vines, a preparation of millet slurry, and a fermentation step to obtain the Boumkaye, has several features. The study of aging process showed probable lactic and alcoholic fermentations. Further, the finished Boumkaye was characterized by a high acidity (pH of 3), an alcohol content of 5 g/100g and contains an appreciable amount of polyphenols (54.46 mg/100g).

Influence of Variety and Maturity Level on Natural Convective Heat Drying of Four Onion Varieties Grown in Senegal

The considerable post-harvest losses (5% to 40% depending on storage time) due to the high water content level of the onion varieties in Senegal are the main cause of the problem of access to local onion all year round. Therefore, drying is one of the techniques that can be used to solve the problem of onion perishability. This study deals with the characterization of naturally convective kinetics drying of four onion varieties in relation to their maturity level. The experiment was carried out using the gravimetric method. The Welch and Turkey statistical tests display a significant difference between the effective diffusivity coefficients depending on the maturity level within each variety and across the four varieties. The effective diffusivity coefficients of the Galmi Violet, Safari, Gandiol F1 and Orient F1varieties range from 2.18 × 10&minus;11 ± 2.69 × 10&minus;12 to 1.32 × 10&minus;10 ± 1.17 × 10&minus;11 m2&sdot;s&minus;1 at a maturity level less than 80%. When the maturity level is greater than 85%, the effective diffusivity coefficients range from 1.30 × 10&minus;11 ± 1.24 × 10&minus;12 to 8.05 × 10&minus;11 ± 8.94 × 10&minus;13 m2&sdot;s&minus;1. As far as the activation energy is concerned, the study only reveals a significant difference between the varieties whatever the maturity level is. The Galmi Violet variety stands out with an average activation energy of 66.71 ± 0.12 KJ&sdot;mol&minus;1 K&minus;1 for the maturity level below 80% and 58.74 ± 0.11 KJ&sdot;mol&minus;1 for the maturity level above 85%. For the three remaining varieties, the average activation energy ranges from 58.15 ± 0.19 to 59.12 ± 0.13 KJ&sdot;mol&minus;1 for a maturity level less than 80% whereas the rates go from 47.63 ± 0.28 to 49.96 ± 0.77 KJ&sdot;mol&minus;1 when the maturity level is greater than 85%. In summary, the higher the maturity level is, the lower the effective diffusivity coefficients will be. The same tendency was observed with the activation energy. The Galmi Violet variety represents the limitative one in case of the drying of the four varieties mix together.

<i>Saba senegalensis</i>: Key Features and Uses

Native of West Africa, Saba senegalensis belongs to the family of Apocynaceae, and is a wild plant that is mainly exploited in the diet. It grows mainly along riverbanks, in wooded savannah areas in humid areas, in gallery forests and in rocky ravines and hills. Saba senegalensis is a large woody liana with white latex, dark gray bark, can reach more than 40 m high and a trunk that can measure up to 47 cm in diameter. The fruit is a globose shell, 7 to 10 cm long, 6 to 8 cm wide. The leaves are opposite, elliptical, dark green in color, about 8 to 15 cm long and 4 to 6 cm wide. This fruit is characterized by its richness in antioxidant molecules especially vitamin C (480 mg/100 g) and total polyphenols (945.83 mg/100 g). The fruit contents 41.43 until 80% water with a low pH (2.24). In Senegal, the fruit is eaten as it or transformed into puree, nectar, syrup, canned etc. It is a plant that has enormous therapeutic virtues, from the fruit to the roots through the leaves, bark, and latex. Despite its high nutritional potential, its many therapeutic virtues and its economic potential, Saba senegalensis remains under-exploited. Further researches on the nutritional and therapeutic properties deserve to be conducted.

Antioxidant Activity of Hydro-Acetonic, Hydro-Methanolic and Aqueous Leaf and Bark Extracts of <i>Sclerocaria birrea</i>(A. Rich.) Hochst

Bioactive compounds in plants are associated with the reduction of chronic diseases. The free radical scavenging activity of different extracts of a medicinal plant, Sclerocarya birrea, has been investigated using the DPPH test, ABTS test and FRAP. Three extracts were prepared from the leaves and bark: hydro-methanolic, hydro-acetonic and aqueous. Phytochemical screening was carried out the standard methods followed by the determination of the polyphenol by Folin-Ciocalteu method. The analysis of variance (ANOVA) with the STATISTICA 7.1 and statistical significance was set at p < 0.05. Evolution of percent inhibition (PI) as well as the IC50 of the extracts was obtained using the Origin Pro 8.5 software and Microsoft Excel. The results show that the bark extracts are about twice as rich in polyphenols as the leaves. With DPPH at 1.25 mg/mL, the bark has a PI of 91.04% ± 0.001% while leaves, reach 99.80% ± 0.021%. As for the ABTS test, the bark extract reached its maximum activity at 1.25 mg/mL with a PI of 99.80% ± 0.003% while leaves extract greater value of PI is 99.75 ± 0.003 at 2.5 mg/mL. With FRAP test at 1.25 mg/mL, the bark has a PI of 79.29% ± 0.005% while leaves, reach 80.33% ± 0.001%. The IC50 of the bark and leaf extracts on the smallest DPPH are 0.156 ± 0.001 mg/mL in hydro-methanol, 0.301 ± 0.00 mg/mL in hydro-acetone and 0.407 ± 0.00 mg/mL in aqueous extract. With ABTS test, the best IC50 are obtained with hydro-acetone extracts with value of 0.247 ± 0.001 mg/mL for bark and 0.248 ± 0.0005 mg/mL for leaves while in hydro-methanolic and aqueous extracts the best IC50 are respectively 0.255 ± 0.00 mg/mL and 0.463 ± 0.00 mg/mL. Using ascorbic acid as our standard, the PI was 94.86% ± 0.008% with an IC50 of 0.213 ± 0.00 mg/mL. According to these results, the reducing power of the bark is slightly higher than that of the leaves. We can say that the bark has better activity than the leaves and the alcoholic extracts have given better results than the aqueous extract.

Proximate and Major Minerals Components of the Edible Pulp of <i>Momordica charantia</i>Fruit

Momordica charantia (Cucurbitaceae), is a plant commonly used in traditional medicine in Senegal whose fruits are weakly consumed by the population. However, no data exists on the nutritional intake of the latter. This work aims to determine the physicochemical and biochemical characteristics of the pulp of Momordica charantia. The study focused on two lots of fruits from two geographically different regions of Senegal (Dakar and Fatick). The biochemical analyses of the pulp showed average values of protein from 2.39 ± 0.01 g/100 g to 3.19 ± 0.01 g/100 g;reducing sugar from 4.22 ± 0.10 g/100 g to 3.55 ± 0.10 g/100 g;totals sugar from 4.43 ± 0.02 g/100 g to 3.38 ± 0.58 g/100 g. The average contents of polyphenol and flavonoids were respectively from 1.91 ± 0.04 g/100 g to 1.04 ± 0.09 g/100 g and 32.59 ± 0.04 mg/100 g and 20.75 ± 1.19 mg/100 g. According to these results, the fruit of M. charantia may be considered as rich in antioxidant. At the opposite, it is very weak in mineral elements, such as calcium and potassium (1.01 mg/100 g;3.38 mg/100 g). Meanwhile, the seeds content 24% of lipids. Thus, investigations should be done on its biological proprieties, physical and biochemical components.

Traditional Mead “Bessoudioury” from Senegal: Process and Characterization

Mead is a beverage obtained by alcoholic fermentation of honey, with an ethanol content of 8% to 18% by volume. In Africa, mead manufacturing methods rely on heating honey and adding extracts of fruits, herbs or spices. “Bessoudioury” mead is then prepared according to the traditional process of the Bassari and Bedick peoples of Kedougou (Senegal). This work on “Bessoudioury” aims to describe and characterize the manufacturing processes. It was also to evaluate the chemical and microbiological characteristics. The study focused on three Kedougou production sites. The manufacturing process of “Bessoudioury” includes a honey heating, a formulation step by adding wine of either Borassus aethiopicum Mart. or Elaeis guineensis. This step is followed by a fermentation’s one during two days. Wine is considered as the essential sources of yeasts for the production of alcohol. “Bessoudioury” has an ethanol content of 8% (v/v). Moulds and Streptococcus were not detected in this mead. According to its polyphenols content, this mead has a nutritional interest, but the process deserves to be reviewed to preserve nutrients.

Monitoring of Anthocyanins and Colour in Electrochemically Processed <i>Hibiscus sabdariffa</i>Juice

The vital role of anthocyanins in Hibiscus sabdariffa L. is now known to most consumers. The richness of anthocyanins in antioxidants, vitamin C, minerals, etc., provides Hibiscus juice with proven nutritional qualities. The health requirements of recent years have made food products with added preservatives or processed at high temperatures less popular, thus explaining the new orientations towards innovative and interdisciplinary technologies. Anthocyanins from Hibiscus sabdariffa L. are, however, sensitive to degradation factors such as temperature, light, enzymes and also oxygen. The instability of anthocyanins has long been a subject of research using classic techniques such as heat treatment, the results of which are often limited by the rapid degradation and above all the destruction of the nutritional and organoleptic qualities of the product. Oxygen dissolved in juices is so far treated by bubbling with an inert gas or by adding other molecules such as preservatives which can cause a lot of health damage. The electrochemical approach is a new stabilisation technique that reduces the dissolved oxygen in the juice, cold and without the addition of other molecules. The electrolysis of Hibiscus juice was carried out by noble electrodes (Platinum and Stainless Steel) with a well-characterised Time/Potential or Time/Intensity couple. The electroreduced samples and the control were then stored at 4°C, 25°C and 37°C for more than 6 months. Monitoring of anthocyanins in the first month, of the samples and the control, showed a significant difference of 10% between the electroreduced extract and the untreated control at 37°C, which had previously been problematic for the heat treatment and even for the other membrane techniques. Oxygen reduction on the platinum electrode/ECS allowed the retention of more than 10% of anthocyanins after 4 weeks of storage at 25°C and 37°C. At 4°C, a significant difference of 5% between the electro-reduced Hibiscus juice and the control was maintained until the fifth month of storage with the 1/5 ratio (calyx/water). Non-significant losses in anthocyanin (10 mg/l), for the juice with reduced dissolved oxygen, were noted for the 1/5 and 1/15 ratios during the first month of storage at 4°C against 24 mg/l of significant losses for the 1/20 ratio. However, the untreated control showed significant losses for the ratios 1/20, 1/15 and 1/5. Oxygen dissolved in the juice therefore considerably degrades the anthocyanins of Hibiscus sabdariffa L. from the first month of storage at 4°C.

Impact of Extraction on Biochemical Properties and Antioxidant Potential of Momordica charantia L. Seeds’ Oil

In this study, the influence of provenance and extraction methods on the physicochemical properties and the antioxidant potential of M. charantia seeds oil were evaluated. The oil is obtained on the one hand by cold extraction with hexane and on the other hand by hot extraction with soxhlet. The results obtained show that the extraction yield is significantly impacted by the extraction methods and the origin of the seeds. In addition, the soxhlet extraction gives a higher oil yield (32.07 ± 0.01). Cold extraction has made it possible to obtain oils with less attenuated physicochemical characteristics. Indeed, the acid numbers are high in the oils extracted by soxhlet (5.92 ± 0.25;4.25 ± 0.62 and 13.86 ± 0.83) than in those cold extracted with very low peroxide for all the oils obtained. On the other hand, the iodine and refractive indices are high in oils obtained cold (91.58 ± 0.85;100.74 ± 0.03 and 102.08 ± 0.28) (1.53 ± 0.01;1.52 ± 0.01 and 1.52 ± 0.01) with low saponification indices. The polyphenol concentrations and the anti-free radical activity are higher with the oils obtained cold (0.086 ± 0.001;0.08 ± 0.000 and 0.09 ± 0.01 mgEAG/g of oil) and (DPPH) (55.75% ± 1.16%;55.03% ± 0.72% and 56.35% ± 0.45%). The color parameters (L*, a* and b*) of the different oils extracted also vary depending on the extraction method used. Principal Component Analysis (PCA) and correlation analysis were performed on the physicochemical properties and the antioxidant potential of the extracted oils. Therefore, the results suggest cold extraction to obtain a good quality and oxidation resistant oil.

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.

Evaluation of Phenolic Content and Antioxidant Activity of Aqueous Extracts of Three Carica papaya Varieties Cultivated in Senegal

The aqueous extracts of different parts (old leaves (OL), young leaves (YL), peels (PE) and delipidated seed residues (DS)) of three varieties of papaya are studied. Extraction conditions are optimized: an extraction time of 20 minutes, a temperature of 70°C and a plant material/water mixture of 1% give the best yield of polyphenol. The amount of polyphenols, flavonoids, saponins and proanthocyanins of each aqueous extract was investigated. Antioxidant activities are measured using two different methods (DPPH and ABTS). The delipidated seeds (DS) of V1 have the highest total phenolic content (TPC = 72.56 ± 3.16 mg GAE/g) while they have the lowest total flavonoid content (TFC = 0.22 ± 0.01). With regard to saponins, the PE of V3 is much richer in saponins (194.03 ± 15.78 mg AeE/g) than all the other extracts studied. The OL of V2 and PE of V1 contain the most proanthocyanidins with very similar values of 2.51 ± 0.03 mg CE/g and 2.53 ± 0.34 mg CE/g respectively. The study of the antioxidant activities of the extracts showed a correlation between the amount of polyphenols and IC50. DPPH OL and YL V2, which are rich in polyphenols, have the lowest IC50 of 0.072 mg/ml and 0.080 mg/ml respectively, whereas for ABTS we have PE of V1 that is very rich in polyphenols which has the smallest IC50 value of 0.218 mg/ml.