Chapters 8.21
8.21-Seaweed Value Addition
Yu Bi , University of Guelph, Canada
Suggested citation for this chapter.
Bi,Y. (2022) Seaweed Value Addition,In Farmpedia, The Encyclopedia for Small Scale Farmers. Editor, M.N. Raizada, University of Guelph, Canada. http://www.farmpedia.org
Introduction
Seaweed is a colloquial term referring to a variety of marine plants and algae including red algae, brown algae and green algae. It has been widely recognized as food for human consumption, and meanwhile there is growing attention on the usage of seaweed as crop fertilizers. In 2003, the Food and Agriculture Organization of the United Nations (FAO) estimated the total value of production of seaweed at US $6 billion of which US $5 billion represented food consumption. Seaweed production in the marine industry has brought nations significant economic benefits. The utilization of raw seaweed comes either from seaweed farms or seaweed harvested from the wild. As wild seaweed production can be anywhere on the coastline or in the ocean, the majority of farmed seaweed production comes from China (60%), Southeast Asia, Indonesia (21%), Philippines (9%) and Malaysia (1%) according to FAO (FAO, 2003). As a type of marine resource, seaweed farming plays a significant role in improving the lives of smallholder farmers, because it can be performed as an alternative to fish for increasing income (Hehre and Meeuwig, 2016). Despite the desired global market and growing demand for seaweed products, subsistence farmers still predominate in southeast Asia with respect to farmed seaweed production. Finding possible and realistic solutions for subsistence farmers working in this industry is needed other than selling only the raw commodity.
Adding value to seaweed production
Liquid seaweed extract
Seaweed as bio-stimulants
As the attention to less usage of artificial fertilizer and pesticides grows, researchers have been turning their attention to finding substitutes from nature. Seaweed extract has been added to soil to improve yields since the extracts act as plant growth regulators and increase plant uptake of inorganic substances from soil. It has been shown to be effective as natural fertilizers (Kocira et al. 2018, Hernández-Herrera et al. 2014 and Basavaraja et al. 2018). Kocira et al. also looked at the increased nutritional value of the crops applied with seaweed extract containing bio-stimulants (2018). Promising outcomes confirmed the market value of seaweed extract.
Production of liquid seaweed extract
Seaweed is very rich in nitrogen, phosphorus and potassium which are macronutrients that plants require for optimal growth, and thus liquid seaweed extract could be implemented as crop fertilizers. Nowadays, liquid seaweed extract is either directly sprayed on the plants or on soil. Often liquid seaweed extract is produced in a concentrated form and then diluted prior to usage. There are two easy steps for making liquid seaweed extract (Zodape, 2001). First, seaweeds (e.g. brown algae) are chopped into pieces and then boiled in distilled water, and depending on the ratio of seaweed and boiled water, the concentration will vary. Producing liquid seaweed extract powder makes transporting products easier, and it is added to water proportionally based on the concentration needed. However, the process of turning liquid seaweed extract to powder requires expensive drying machinery with vacuum treatment, and this method would not be quite practical for subsistence farmers to practice.
Cost analysis of production
It is realistic for subsistence farmers to implement these value additions for multiple reasons. First, little educational background is required. The required equipment cost is low, and the labour needs are minor. Packaging and transporting the liquid seaweed extract would increase the cost of production; nevertheless, well packaged products are able to be sold in greater number and increase the range of the market. This practice is possible to implement without electricity since heat can be generated by old fashion fire. However, heat treatment and boiling increase the safety concerns for subsistence farmers, especially women and children.
2. Seaweed production as food/snacks
Seaweed paper (nori/laver) in the food and snack industry
Nori and seaweed laver are considered popular foods and snacks. These seaweed sheets are made from red algae, Porphyra, and have existed for centuries. According to FAO, the combined production from Japan, China and Korea alone was just over one million tonnes in wet weight, yet it had the highest value among the cultivated seaweeds, at US$1200 per wet tonne (1999).
Food and snack production of seaweed at a local scale
As seaweed that is consumed as food is the largest contributor to global profits associated with seaweed production, encouraging subsistence farmers to undertake food related production is practical and applicable. The production of nori can be demonstrated in a few steps. Post-harvested red algae are cut into small pieces, and then a model is used to make a regular shape by mashing the grounded pieces of seaweed on a bamboo sheet for further drying. Subsistence farmers can use solar energy and sunlight to dry nori, so no electricity is necessarily needed. There are some different types of seaweeds that could be dried and used in soup making. A similar process could be applied to these products as well. Once the seaweeds are harvested from the water, smaller pieces are separated and sun-dried. These products are easy to preserve as long as they are kept in a cool and dry environment, providing a longer shelf-life.
Cost analysis of the production
Dried seaweed products are easy to be transport as they are lighter in weight compared to wet seaweed, allowing subsistence farmers to sell to hotels or restaurants. A mechanical heat drier for food processing could also be purchased from the online retailer Alibaba at a low price (see below). However, if a food drier machine is used, electricity would be needed. An optional solution for subsistence farmers that are out of reach of electricity would be to use solar panels to run the food drier (see below). Machinery operation would speed up the production, allowing farmers to produce more though with additional costs.
Critical analysis on seaweed products practice
The problem with seaweed value addition is that there is a potential shortage of global seaweed, despite recent human cultivation, caused by climate change and seawater pollution (Chung et al, 2017). Sustainable usage of seaweed is a future research direction. In fact, the processed seaweed left over from either alginate extraction or liquid seaweed extraction can be used in waste water treatment (FAO, 2003). Seaweeds have the capability to remove excess nitrogen and phosphorus containing compounds from waste water, and at same time no harm would be caused by leaving the leftover seaweed in the water. Seaweed related productions could help subsistence farmers but proper education on sustainable management of production should be considered.
Useful Links to get started
- Food and Agriculture organization of the United Nations website, http://www.fao.org/docrep/006/y4765e/y4765e00.htm#Contents
- https://www.acadianseaplants.com/plant-growth-development-products
References
1. Food and Agriculture Organization of the United Nations, accessed on November 12, 2018. http://www.fao.org/docrep/006/y4765e/y4765e00.htm#Contents
2. Basavaraja, P. K., Yogendra, N. D., Zodape, S. T., Prakash, R., & Ghosh, A. (2018). Effect of seaweed sap as foliar spray on growth and yield of hybrid maize. Journal of Plant Nutrition, 41, 1851-1861.
3. Chung, I. K., Sondak, C. F. A. and Beardall, J. (2017). The future of seaweed aquaculture in a rapidly changing world, European Journal of Phycology, 52, 495-505.
4. Hehre, E. J., and Meeuwig, J. J. (2016). A Global Analysis of the Relationship between Farmed Seaweed Production and Herbivorous Fish Catch. PLoS One, 11, 1-17.
5. Hernández-Herrera, R. M., Santacruz-Ruvalcaba, F., Ruiz-López, M. A., Norrie, J., and Hernández-Carmona, G. (2014). Effect of liquid seaweed extracts on growth of tomato seedlings (Solanum lycopersicum L.). Journal of Applied Phycology, 26, 619-628.
6. Kocira, S., Szparaga, A., Kocira, A., CzerwiAska, Czerwińska, E., Wójtowicz, A., Bronowicka-Mielniczuk, U., Koszel, M. and Findura, P. (2018). Modeling Biometric Traits, Yield and Nutritional and Antioxidant Properties of Seeds of Three Soybean Cultivars Through the Application of Biostimulant Containing Seaweed and Amino Acids. Frontiers in Plant Science. 9, 1-18.
7. Sharma, L., Banerjee, M., Malik, G. C., Gopalakrishnan, V. A., Zodape, S. T., and Ghosh A. (2017). Sustainable agro-technology for enhancement of rice production in the red and lateritic soils using seaweed based biostimulants. Journal of Cleaner Production, 149, 968-975.
8. Zodape, S.T. (2001). Seaweeds As a Biofertilizer. Journal of Scientific and Industrial Research. 60. 378-382.