# Evaluation and Characterization of Alginate Extracted from Brown Seaweed Collected in the Red Sea
## 2 Materials and Methods
### Biochemical Composition of the Extracted Sodium Alginate
[55] (19.1% DW \(\pm\) 1.62) in the Red Sea Coast in the Sudan region. However, the alginate yields obtained in this study were in accordance with the range of the alginate yields of the alginophytes species analyzed by [PERSON] et al. [56], such as _Macrocystis pyrifera_ (1-21% DW), _Ascophyllum nodosum_ (15-20% DW), and _Saccharina japonica_ (20-26% DW) (normally used as a raw source by the alginate industry). However, a lower percentage than the alginate extracted from _Durvillaea antarctica_ (from 37 to 52% DW) by [PERSON] and [PERSON] was observed [57]. As stated by [PERSON] et al. [58], the yield of alginate extraction depends on the seaweed's age and the species used and the environmental conditions, such as light intensity, water temperature, currents, and nutritional status, as well as the extraction techniques. Moreover, the alginate yield demonstrates the seaweed's potential as a dietary fiber raw source to humans for direct consumption, as they are important for human welfare [59]. The results demonstrate that the selected seaweed's potential as a dietary fiber source for human ingestion is within the limits (Table 6) [60]. The recommended dietary fiber intake (RDFI) is 25g/day for a normal adult person; above this limit, there is a possibility of the appearance of an dietary fiber-related adverse effects in human health [1; 59]. Nevertheless, because of the large miscellany of seaweeds compounds, principally their mineral content, the recommended daily intake for a nonspecific seaweed is typically only 5 g DW/day to a human [61; 62]. In this case, the seaweed intake represents a low consumption, however important, of dietary fiber (RDFI between 2.68 and 4.44%/day) to the human health, because of the positive effects of the alginate cited above, even at a low percentage (for example, anti-obesity and anti-diabetes activities of alginate is observed at a concentration lower than 0.1%) [63]. Consequently, these seaweeds can be further explored as a natural and unprocessed food source. In this case, seaweed is directly used as a food source as an alternative to traditional dietary fiber sources, such as fruits, vegetables, oat bran, barley, seed husks, flaxseed, psyllium, dried beans, and lentils [64]. To be exploited by the food industry, the extracted alginate needs to be evaluated so as to overview its potential to be accepted as a safe ingredient at an industrial level. For this, there is a need to characterize the alginate extract with various physicochemical methods so as to certify the alginate's quality [1]. Consequently, this study aimed to give an insight into the sodium alginate quality of the selected seaweeds. The physical analysis showed that the obtained sodium alginate had a pale-yellow color and its moisture content varied between 6.4 to 13.1%. These results demonstrate that these seaweeds' alginate is good according to the FAO report written by [PERSON] [65], where it is stated that the color of sodium alginate is white to yellowish-brown and the moisture content is 15%. The pH value of the obtained sodium alginate showed an alkaline nature and ranged between 9.6 and 9.8. [PERSON] et al. [66] reported that sodium alginate is stable at a pH range from 5 to 10; furthermore, the Food Chemical Codex (FCC) [67] has established that the food quality of sodium alginate in the food industry needs to be at pH 3.5-10. When comparing the results of the extracted sodium alginate with these standards, it can