Functional foods are those foods which are capable of imparting a therapeutic benefit to the consumer. In addition to the basic human nutrition, they provide extra benefits in the portion consumed. Dietary fibre is one such example of functional foods. Dietary fibres comes under the category of prebiotic carbon-rich foods.
The regular consumption of dietary fibre positively influences the overall human health. At the cellular level, prebiotically-induced proliferation of beneficial microbial strains alters the gut microbiome residing in the cellular wall. Some of the noteworthy effects of dietary fibre include reduced risk of tumour and constipation, hypercholesterolemia, diabetes and obesity (Green et al., 2020).
The worldwide production of marine macroalgae has been estimated to be >36 million tonnes corresponding to USD 15 billion. Amongst Southern Asian countries, China and India have largest cultivation of seaweeds. In developing countries, the majority of seaweed farming activities are carried out by women and their involvement is quite complex. In south Asian regions, seaweed farming is carried out as family-owned businesses. Kelps are the most commonly cultivated seaweed in developed countries. Some of the highly cultivated and economically significant seaweeds are Eucheuma sp., Gracilaria sp., Kappaphycus sp., and Ulva sp. Around 97% of the seaweed production comes from aquaculture and barely 3% comes from harvesttaion of wild populations. The seaweed industry is spread across 48 countries and financially supports approximately 6 million small scale farmers. In developing countries, the majority of seaweed farming activities are carried out by women and their involvement is quite complex. In south Asian regions, seaweed farming is carried out as family-owned businesses. Kelps are the most commonly cultivated seaweed in developed countries. In case of underdeveloped and developing countries seaweed farming considerably contributes in income generation amongst underprivileged coastal communities. This increasing popularity has given edible marine algae to be perceived as a global food ingredient. The nutritional composition of macroalgae, depends largely on the species, harvestation time and habitat, and also on other extrinsic conditions such as temperature and light intensity.
The usage of green solvents allows to sustainably accomplish an improved and highly selective extraction analysis. These non-conventional extraction techniques exhibit superior potential for highly specific extraction of plant products. When utilising integrated techniques, it is necessary to select the best operating conditions for scalable and cost-effective extraction of raw material to attain the best yields having negligible or no degradation. Survey studies showed that ultrasonic enzyme-assisted extraction/UAE and microwave-assisted extraction/MAE are the highly favoured extraction techniques for plant based polysaccharides. Enzyme-assisted extraction procedure is considered supremely green, energy-efficient, and ecologically friendly method which provides high-quality products from plants.
Owing to fast culinary globalization, eastern food habits have now been integrated into western food practices. Seaweeds have been used as either additives or flavouring ingredients in Asian platter. Seaweeds comprise of about 21% of meals in oriental cuisine particularly in Japan. Nutritionally, they are a powerhouse of fibre, proteins, lipids, sulfated polysaccharides. It has a richness of vital micro-nutrients such as potassium, calcium, phosphorus, and vitamins. Further, seaweeds are natural source of hydrocolloids supplied in the food industry. Sulfated polysaccharides (SP) such as carrageenans, alginates, and agars are the chief hydrocolloids synthesised in brown and red algae. Carbohydrate compounds apart from having organoleptic features and nutritional value. Prebiotics are oligosaccharides that remain undigested in small intestines. They selectively stimulate the growth of some healthy microbes in the colon and help in boosting overall gut immunity. The criteria for an oligosaccharide to function a prebiotic should be: 1) The molecule must be highly resistant to acidity in the intestine. 2) It should be non-absorbtive in the upper gastrointestinal tract. 3) It must easily fermentable by the beneficial microflora in small intestine.
Immunonutrition is an interdisciplinary field which relates to activation of immune response through nutrition intake. It includes broad aspects of nutrition, immunity, infection and inflammation. SPs of marine algae are a substitute source of innovative therapeutic candidates for antiviral molecules. For instance, fucoidans showed considerable antiviral activity against cytomegalovirus, HIV and herpes simplex virus types. Likewise, fucoidans, carrageenans and sulfated rhamnogalactans have exhibited considerable inhibition towards the entry of enveloped viruses (i.e. herpes and HIV) into cells. Fucoidan has reportedly depicted α-glucosidase inhibition to treat diabetes as well. Additionally, Fucoidan exhibited anti-tumour activities by activating apoptotic proteases such as caspase-8 and -9 in HeLa and MCF-7 cells at dosage range of 10–1000 ppm (Luthuli et al., 2019).
Green, M., Arora, K., & Prakash, S. (2020). Microbial medicine: prebiotic and probiotic functional foods to target obesity and metabolic syndrome. International journal of molecular sciences. 21(8): 2890.
Mena-García, A., Ruiz-Matute, A. I., Soria, A. C., & Sanz, M. L. (2019). Green techniques for extraction of bioactive carbohydrates. TrAC Trends in Analytical Chemistry. 119: 115612.
Lafarga, T., Acién-Fernández, F. G., & Garcia-Vaquero, M. (2020). Bioactive peptides and carbohydrates from seaweed for food applications: Natural occurrence, isolation, purification, and identification. Algal research. 48: 101909.
Luthuli, S., Wu, S., Cheng, Y., Zheng, X., Wu, M., & Tong, H. (2019). Therapeutic effects of fucoidan: A review on recent studies. Marine Drugs. 17(9): 487.