Fermentation of sugar kelp (Saccharina latissima)—effects on sensory properties, and content of minerals and metals

Abstract

Fermentation is an ancient technique for preserving food and feed, and for moderating taste and texture of foods. Fermentation of seaweeds for generating novel food products has yet only been described for few red algae. Here, sugar kelp (Saccharina latissima) was heat-treated and fermented using lactic acid bacteria (LAB). Taste, smell and texture of the fermented product was compared to fresh sugar kelp and two commercial seaweed products (nori and wakame). Tissue contents of dry matter, nitrogen, mannitol, and selected minerals and trace metals of the fresh and fermented sugar kelp were quantified and compared. In the fermentation process, the pH was reduced to 4.5 within 40 h, with LAB counts increasing 100-fold and no Bacillus cereus present. Heat-treatment and fermentation caused a reduced saltiness and umami flavour of the sugar kelp, a less slimy visual appearance and a reduced smell of sea, whereas the texture and protein content was unchanged compared to the fresh sugar kelp. The fermented sugar kelp had a stronger bite than nori and wakame, a stronger smell of sea and a more salty, irony and umami rich taste than nori, but less umami and salt taste than wakame. The fermentation process reduced the contents of sodium (− 15%), cadmium (− 35%) and mercury (− 37%) in the sugar kelp. LAB fermentation of sugar kelp showed promising for broadening the food market for seaweeds as the fermented product had a milder taste, improved visual impression and smell, and a reduced content of harmful trace metals.

Lactic acid fermentation in the development of a seaweed sauerkraut‐style product: Microbiological, physicochemical, and sensory evaluation

“…The higher levels of fructose in the current study, which were higher in the SK than WK samples, suggest that glucose was preferentially metabolized by the LAB, as expected. Kelps also contain the glucan laminarin and the sugar alcohol mannitol, which is reportedly fermentable by L. plantarum (Bruhn et al., 2019) and likely served as a readily available source of carbon during fermentation. Despite microbial consumption of sugar (and likely of mannitol) that can be inferred from the rising levels of LAB and decreasing pH, total concentrations of sugar increased for the first 7 days of fermentation, most likely due primarily to diffusion of solutes from cabbage to brine.…”

“…Similarly, Bruhn et al. (2019) evaluated the effects of heat treatment and inoculation (L. plantarum ) on the sensory and nutritional quality attributes of lacto‐fermented SK. They reported that the heat‐treated and inoculated SK was successfully stabilized within 48 hr and had a milder flavor and odor as compared to the fresh SK.…”

Uncovering Prospective Role and Applications of Existing and New Nutraceuticals from Bacterial, Fungal, Algal and Cyanobacterial, and Plant Sources

“…Algae, and to be specific seaweed, is considered a good source of multivitamins [112]. Saccharina latissima (sugar kelp) for instance is considered a good source of vitamin C in its dried and fermented form [113,114]. Undaria pinnatifida and Porphyra purpurea have high contents of vitamin A besides having the known activity of lowering the bad cholesterol (LDL) and being a good natural source of proteins and carbohydrates [115].…”

Crossroad of Tradition and Innovation – The Application of Lactic Acid Fermentation to Increase the Nutritional and Health-Promoting Potential of Plant-Based Food Products – a Review

“…through solid-state fermentation were reported to be more efficient [Rodríguez-Jasso et al, 2013]. However, the fermentation of seaweed can be carried out by LAB or using co-cultures with LAB strains to improve the sensory attractiveness of new products [Bruhn et al, 2019]. It is also highly probable that studies on the potential role of fermented seaweed compounds might be soon reported due to the growing interest in possible antiviral and antibacterial effects of seaweeds reported by traditional Eastern medicine.…”