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.

Lycopen’s Stability in Watermelon Juice (<i>Citrullus lanatus</i>) Regarding to Technological Routes

Highly prized by consumers, watermelon is rich in water, but also in micronutrients including lycopene, pigment responsible for the red color. It is also a powerful antioxidant which has many virtues including the prevention and treatment of certain diseases. The transformation into nectar of watermelons combined with treatment could cause several modifications including the alteration of coloring. It is in this context that this study focuses on the variation of the lycopene content in nectars. Thus, nectars of 12°Brix and 15°Brix were prepared from three varieties of watermelon (Sugar Baby, Crimson Sweet and Charleston Gray). To study the stability, two pasteurization scales (85°C/15min and 95°C/15min) and one sterilization scale (105°C/15min) were applied to the different nectars produced. The results obtained showed that the Sugar Baby variety is richer in lycopene (24.39 mg·kg-1) with a higher pH (5.80). In addition, the study showed, for the Sugar Baby variety, an increase of lycopene with the addition of sugar and the heat treatment (a maximum of 42.83 mg·kg-1 for SbF12T105). On the other hand, for the Crimson Sweet and Charleston varieties, the highest rate of lycopene, except the heat-treated ones, are those formulated at 12°B (10.46 mg·kg-1 for CrF12T105 and 18.40 mg·kg-1 for ChF12T105). Without any health consequences, the formulation combined with heat treatment would preserve the lycopene content of watermelon nectars.

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.