Bioactive compounds with diverse chemical structures play a significant role in disease prevention and maintenance of physiological functions. Due to the increase in industrial demand for new biosourced molecules, several types of biomasses are being exploited for the identification of bioactive metabolites and techno-functional biomolecules that are suitable for the subsequent uses in cosmetic, food and pharmaceutical fields. Among the various biomasses available, macroalgae are gaining popularity because of their potential nutraceutical and health benefits. Such health effects are delivered by specific diterpenes, pigments (fucoxanthin, phycocyanin, and carotenoids), bioactive peptides and polysaccharides. Abundant and recent studies have identified valuable biological activities of native algae polysaccharides, but also of their derivatives, including oligosaccharides and (bio)chemically modified polysaccharides. However, only a few of them can be industrially developed and open up new markets of active molecules, extracts or ingredients. In this respect, the health and nutraceutical claims associated with marine algal bioactive polysaccharides are summarized and comprehensively discussed in this review.

The aim of this work is to study the influence of the physicochemical characteristics of neem seeds, according to their mass and oil content, on the production of biodiesel. After the physical characterization of the seeds and extraction of the oil (triglycerides), biodiesel was produced from crude neem seed oil by transesterification with ethanol in the presence of sodium hydroxide. This study shows that the physicochemical characteristics of these seeds vary according to the origin of the samples. The seeds from Zidim, with a mass average of 200 seeds evaluated at 141.36 g and an almond content of 40.70%, have better characteristics compared to those collected in the city of Maroua, with average values evaluated at 128.00 g and 36.05%, respectively. Almonds have an average lipid content of 53.98 and 56.75% for the Maroua and Zidim samples, respectively. This study also reveals that neem oil, by its physicochemical characteristics, has a satisfactory quality for a valorization in the production of biodiesel. However, its relatively high free fatty acid content is a major drawback, which leads to a low yield of biodiesel, evaluated on average at 89.02%, and requires a desacidification operation to improve this yield. The analysis of biodiesel indicates physicochemical characteristics close and comparable to those of petrodiesel, particularly in terms of calorific value, density, kinematic viscosity, acid value, evaluated at 41.00 MJ/kg, 0.803, 4.42 cSt, and 0.130 mg/g, respectively.

This article is focused on the production of biodiesel from the waste cotton seed oil (WCSO), after purification, as an alternative to fossil fuels. Waste oil was collected from Sodecoton, a factory producing cotton seed oil in the Far North Cameroon. The WCSO was subjected to purification using activated coal, followed by transesterification under basic conditions (potassium hydroxide (KOH)), using methanol and ethanol. Some physico–chemical properties of biodiesel, such as absorbance of waste and purified oil, density, viscosity, water content, acid value, and its energy content were determined. The result of treating the WCSO with activated coal indicated that purification efficiency of activated coal increased with the contact time and the mass of the absorbent. Absorbance results directly proved that activated coal removed unwanted components. In the same way, activated coal concentration and exposure time influenced the level of free fatty acids of WCSO. The yield of methyl ester was 97%, while that of ethyl ester was 98%. The specific gravity at 25 °C was 0.945 ± 0.0601. An evaluation of the lower calorific value (PCI) was done in order to study the energy content of biodiesel. This was found to be a value of 37.02 ± 3.05 MJ/kg for methyl ester and 36.92 ± 7.20 MJ/kg for ethyl ester. WCSO constitutes feedstock for high volume, good quality, and sustainable production of biodiesel, as well as a realistic means of eliminating the pollution resulting from the indiscriminate disposal of waste oils from both household and industrial users.

Tigernut tubers (Cyperus esculentus) are used for the production of vegetable milk, commonly known as “Horchata de chufa” in Spain. The presence of starch in the tuber limits the yield of the milk, since this carbohydrate gelatinizes during the pasteurization of the milk and leads to the considerable solidification of this drink. The present work aims to improve the yields and extraction practice of the milk by an in situ hydrolysis of starch, using exogenous amylases of industrial or vegetable origin. The obtained results show that sprouting improves the extraction yields of tigernut milk, which goes from 50% to about 70%. This improvement in milk yield corresponds to a hydrolysis of about 35% of the starch in the tuber. The use of exogenous amylases leads to starch hydrolysis rates of 45% and 70%, respectively, for amylolytic extracts from sprouted tigernut tubers and amylase, with the corollary of a natural increase in the sweetness of milk. This technical approach makes it possible to produce a naturally sweetened tigernut milk which easily lends itself to pasteurization without a significant increase in viscosity.