Seaweeds are marine macroalgae that are found in coastal areas around the world. Seaweeds typically grow in the intertidal zone where light allows a sufficient amount of growth for seaweeds through photosynthesis, as all seaweeds contain chlorophyll and are photosynthetic (The Seaweed Site, 2016).
Seaweeds are usually found attached to hard substrates, as their environment is subject to strong waves. They have specialized tissues that that serves as anchorage, a holdfast, that is similar to a plant’s root system (The Seaweed Site, 2016). However, there are some species that can float freely in the ocean (Mouritsen et al. 2013b).
Seaweed vary in color. Therefore, they are divided into three categories: Chlorophyta (green), Rhodophyta (Red) and Phaeophyta (Brown) (Mouritsen et al. 2013b). However, the seaweed categories also differ in structural and biochemical features. Brown and red seaweeds are mostly found in marine waters, but green seaweeds can also be found in freshwater systems (The Seaweed Site, 2016).
There are over 10,000 species of seaweed and more continuing to be discovered (Mouritsen et al. 2013b). 6,500 species are red, 1,500 species are green, and 2,000 species are brown seaweeds (The Seaweed Site, 2016).
2. Sea vegetable introduction:
Seaweed can be used in cosmetics and medicine, and food. Seaweeds used in foods are considered sea vegetables because any edible seaweed is termed a sea vegetable. Sea vegetables are super foods that are rich in vitamins and provide important health benefits. In addition, sea vegetables can offer different benefits than land plants. For example, seaweeds can provide 10-20 times more minerals than land plants because seaweeds can obtain minerals from seawater (Makkar et al. 2016).
Sea vegetables are a rich in proteins and prebiotics, are a good source of bioactive compounds, are low in lipids, and contain non-starch polysaccharides (Gupta et al. 2011). Furthermore, the polysaccharides found in sea vegetables have the potential to have medicinal values for the body (Gupta et al. 2011). Sea vegetable are also a good source of fiber and the consumption of seaweeds could reduce the risk of colon cancer (Gupta et al 2011).
Brown, red, and green sea vegetables offer different dietary benefits for human consumption. Red and green sea vegetables are higher in protein and mineral content compared to brown seaweeds (Makkar et al. 2016). Red and greens seaweeds contain 50% and 30% protein content, respectively (Makkar et al. 2016). Nonetheless, brown seaweeds are rich bioactive compounds such as phloroglucinal-based polyphenolic compounds, carotenoids, and polyunsaturated fatty acids (Charoensiddhi et al. 2016). Bioactive compounds can influence human health and act similar to an antioxidant. Furthermore, brown seaweeds contain alginate, laminarin, and fucoidan which makes them have a unique structure that is resistant to digestion enzymes that are found in the human body, making them a source of dietary fiber (Charoensiddhi et al. 2016).
3. Sea vegetable industry:
The sea vegetable industry is a growing industry (Chopin and Sawhney, 2009). Sea vegetables that are used for direct human consumption is a 5.29-billion-dollar industry (Chopin and Sawhney, 2009). This equates to 8.59 million tonnes of sea vegetables (Chopin and Sawney, 2009). The worldwide seaweed industry cultivates approximately 220 seaweed species (Chopin and Sawhney, 2009). The edible sea vegetable market, consists of three dominant seaweed genera: Laminara (or kombu), Porphyra (or nori), and Undaria (or wakame) (Chopin and Sawhney, 2009).
Asian countries are the largest consumers of sea vegetables and most of the world’s sea vegetables are produced in Asian waters (Chopin and Sawhney, 2009). However, the recent radioactive contamination of Asian waters, caused by the leaking Fukushima nuclear plant in Japan, has created quality concerns in sea vegetables for this area (Maine Aquaculture, 2015). Therefore, Maine’s sea vegetable industry has the opportunity to grow because of increasing demands for sea vegetables (Maine Aquaculture, 2015).
The Maine seaweed industry is the number one sea vegetable producer in the United States (). In 2014, 17.7 million pounds of seaweed was collected by Maine harvesters (NBC, 2015). The number of Maine sea vegetable companies has doubled from 10 years ago (NBC, 2015). North American Kelp, Maine Coast Sea Vegetables, SOURCE Maine, VitaminSea, and Atlantic Holdfast Seaweed Company are just some of the more than 20 companies that grow seaweed in Maine. Furthermore, some of these companies have been around for 30 years or more (Maine Seaweed Council, 2016). One company, Maine Coast Sea Vegetables, is harvesting roughly 100,000 pounds of seaweed a year (Maine Coast Sea Vegetables, 2016). Maine Sea Coast Vegetables is selling their products to Amazon, Whole Foods, and other health food stores (Maine Coast Sea Vegetables, 2016).
The success of Maine’s sea vegetable industry comes from the variety of edible seaweeds native to Maine’s Coast such as: Alaria esculenta (or winged kelp), Saccharina latissima (or sugar kelp), and Palmaria palmata (or dulse). These sea vegetables are rich in nutrients.
Kelps are large brown seaweeds that are long and thin with blades. There are about 300 different kinds of kelps that are classified under the laminariales, edible kelps (Mouritsen et al. 2013b). Kelps often create kelp forests in the ocean because of their large size that can reach up to 50 meters long (Mouritsen et al. 2013b).
Kelps are rich in vitamins, minerals, iodine content, and phytonutrients (Mouritsen et al. 2013b). Some minerals found in kelps are calcium, potassium, and magnesium (Mouritsen et al. 2013b). In addition, kelp has a high monosodium glutamate (MSG) content, responsible for kelps umami taste (Mouritsen et al. 2013b). Therefore, kelp is often incorporated in a variety of foods such as, soup, salad, cooked dishes, or sprinkled on food like a spice. However, some varieties of kelps are better for human consumption because some are thin and soft, while others can be undesirably thick and tough.
The winged kelps and sugar kelps found in Maine offers consumers important health benefits. The winged kelps are a good source of Vitamin A (Mouritsen et al. 2013b) and protein (FAO, 2016). While sugar kelps offer medicinal and unique flavor characteristics to consumers. Sugar kelps are a unique kelp because they have a sweeter taste (Mouritsen et al. 2013b). When sugar kelps are dried, they excrete polysaccharides and mannitol. Mannitol is the compound that is responsible for the sweet taste of this sea vegetable.
Dulse are red sea vegetables harvested from the early summer to fall (Maine Coast Sea Vegetables, 2016). Dulse is a product that is found in many food dishes across the world and is also commonly consumed as a snack. Dulse can also be used as a nutritional supplement because they are rich in iodine, protein, and iron (Mouritsen et al. 2013a).
While many of Maine’s seaweeds are freshly harvested, few seaweeds are sold fresh to the market. Dried sea vegetables have a longer shelf life than fresh sea vegetables therefore, edible sea vegetables are sold in either frozen or dried forms 99% of the time (). The sales of dried sea vegetable products were up more than 40%, meaning the demand for sea vegetables is increasing ().
One alternative to drying sea vegetables is fermenting sea vegetables. Fermenting sea vegetables utilizes fresh seaweed and creates a shelf stable product. Furthermore, sea vegetables are super foods that are rich in vitamins and provide important health benefits. For this reason, fermenting seaweed could increase sea vegetables’ health potential and create a non-dairy alternative probiotic.
Fermentation can be described as respiration without air, meaning that microbial enzymes can cause chemical changes in food anaerobically. In addition, fermentation is a process where an organism converts a carbohydrate into an alcohol or an acid. One process of fermentation is lacto-fermentation, where lactic acid bacteria convert carbohydrates, such as glucose, from fruits and vegetables into lactic acid (Cultures for Health, 2016).
Lacto-fermentation utilizes lactic acid bacteria. Lactic acid bacteria are gram positive, micro-aerophillic, bacteria. There are many different lactic acid bacteria species, however Lactobacillus, Leuconostoc, Pediococcus and Streptococcus are the main species involved in desirable food fermentations (FAO, 2016). Lactic acid bacteria are heterofermentors or homofermentors. Heterofermentors produce lactic acid, acetic acid and other products, while homofermentors produce mostly lactic acid. Lactobacillus bacteria are unique and are heterofermenters or homofermenters depending on the species (FAO, 2016).
The production of lactic acid during fermentation is dependent on several variables. Fermentation of vegetables can occur naturally because of the natural presence of lactic acid bacteria on the vegetable (Panda et al. 2008). However, the using a starter culture in fermentation provides a more reliable and consistent fermentation (McFeeters 2004, Panda et al. 2008). One of the most common starter cultures used in lacto-fermented products is Lactobacillus plantarum (Panda et al. 2008).
Common variables that can influence the success of lactic acid bacteria growth are temperature, environment, salt content, and oxygen availability (FAO, 2016). Furthermore, lactic acid bacteria growth can also be affected by the carbohydrate source and concentration, amount of oxygen, and pH levels (Gupta et. Al 2006). Changing the pH environment can affect how lactic acid bacteria can inhibit other bacteria (Akbar et al. 2016).
5. Food industry uses for Lacto-fermentation:
One of the reasons lacto-fermentation is used in the food industry is for preservation methods because of its ability to preserve vegetables, increase their shelf, and enhance safety in the food product. The process of fermentation preserves food naturally by decreasing the microbial activity. “Fermentation process reduces available carbohydrates and also produces some organic compounds that exhorts antimicrobial activity (Ross et al., 2002), the most common being propionic acids and lactic acid” (Akbar et al. 2016).
Using lacto-fermentation for food preservation can be also be termed as biopreservation. Biopreservation refers to the use of living microbes to extend the shelf life (Akbar et al. 2016). Bioproservation is natural method that eliminates the use of chemicals and antibiotics in foods, a characteristic that consumers are avoiding in their foods.
Lactic acid bacteria are used for preservation purposes because of their functional properties. “Lactic acid bacteria (LAB) are of particular interest as biopreservation organisms due to their production of lactic acid, acetic acid, hydrogen peroxide and other antimicrobial compounds (Magnusson and Schnurer, 2001)” (Prachyakij et al. 2008). Lactic acid bacteria have antagonistic metabolites and bacteriocins (Akbar et al. 2016). Bacteriocins are natural proteins that have antimicrobial properties that can inhibit the growth of other similar bacteria or unwanted microbes, such as spoilage bacteria and pathogens (Akbar et al. 2016). Different lactic acid bacteria can product varying antimicrobial compounds (Akbar et al. 2016). Lacto-fermentation also preserves the “ascorbic acid, phenols, and colored pigments (b-caro- tene and anthocyanin)” of food which are considered as anti-oxidants (Panda et al. 2008). It is for these reasons that lactic acid bacteria improve the safety, shelf life, and quality of food products and are used in preservation.
Lactic acid bacteria are used for food preservation because of their ability to influence food contamination. Lactic acid bacteria, particularly Lactobacillus plantarum, help inhibit growth of foodborne pathogen in fermented plant products (Ratanburee et al. 2013, Hayisame-ae et al. 2014). Lactobacillus plantarum, was reported to have the most promising ability to control fungi such as yeast and mold in food (Prachyakij et al. 2008). Prachyakij et al. (2008) studied samples of fermented plant beverages that are common to Thailand. Some samples were contaminated with yeast and a total of 72 lactic acid bacteria strains were studied to see which strain could inhibit yeast contamination. It found that mold and yeast spoilage are less likely to occur in a fermented product that uses L. plantarum as the inoculate species and more research needs to be done to determine why this inoculate had the best inhibiting effect.
More commonly, lacto-fermentation is used to create food products with unique flavor profiles. Some examples of lacto-fermented products are sauerkraut, yogurt, kimchi, and kombucha. Lactic acid bacteria have been known to improve the quality and texture of fermented foods and are responsible for creating a unique sour taste (Vries et al. 2006, Akbar et al 2016) because these organisms produce lactic acid, acetic acid, and hydrogen peroxide during fermentation. Therefore, lactic acid bacteria are used as starter cultures because of the role they play in conserving flavor and texture of fermented foods (Vries et al. 2006).
The consumer acceptance of aroma, appearance, texture, and flavor of products with probiotics was tested by Luckow and Delahunty 2003 using blackcurrant juices. A blackcurrant juice that contained Lactobacillus plantarum was compared to seven conventional blackcurrant juices that were popular in the market. Consumers described the probiotic drink as perfumey in aroma and savory and sour in taste (Luckow and Delahunty, 2003). This research shows that drinks with probiotics provide a detectable flavor difference
It was also determined that age and had influenced the acceptance of probiotic juices, where older consumers were more accepting of the probiotic drink. This is possibly because older consumers could be less sensitive to the unique flavor of the probiotic drink. In addition, females that were over 40 preferred the probiotic juices and indicated that they would also drink them more frequently (Luckow and Delahunty, 2003).
Lacto-fermented products provide consumers with important health benefits. Lactic acid bacteria have been known to reduce blood cholesterol levels, resist pathogens, and enhance immunomodulation (Vries et al., 2006). Furthermore, fermented products provide probiotic benefits because of the product’s presence of lactic acid bacteria. Probiotics are “good” bacteria that administer health benefits, like disease prevention, and improved digestion (Hayisame-ae et al. 2014, Luckow and Delahunty 2004) because “probiotics bind the epithelial cells binding sites to compete with pathogenic bacteria by inhibiting the colonization of pathogenic bacteria such as, E. coli and Salmonella (Mazahreh and Ershidat, 2009)” (Akbar et al. 2016).
Probiotics must have the ability to survive in extreme conditions, such as wide pH ranges and tolerance to bile salts in order to ensure that they work in the intestinal passage of the body (Akbar et al. 2016). It can take the human body three hours to digest certain meals and this means that a large number must to survive in the body for a long period of time (Hayisama-ae et al. 2014) In addition, probiotics must be able to produce bioactive compounds that will inhibit the growth of other bacteria (Akbar et al. 2016).
Lactic acid bacteria offer probiotic benefits because of their strong ability to survive in the human gut and inhibit microbes. Duangjitcharoen et al. (2009) studied the probiotic characteristics of Lactobacillus plantarum by researching how this lactic acid bacterium could survive in the gastrointestinal tract. In addition, Duangjitcharoen et al. (2009) confirmed that L. plantarum were safe to use in fermented products after studying mice that consumed the L. plantarum fermented products.
L. plantarum are able to be a successful probiotic because of its ability to survive in the gastrointestinal tract and because they have the ability to survive in a range of differing environments. Furthermore, L. plantarum are commonly found in the gastrointestinal (GI) tract of the human body (Vries et al. 2006). The GI tract of a human is an acidic environment with high salt concentrations. These conditions are similar to the environment in a fermenting process and is why these bacteria can survive in that environment.
6. Vegetable Lacto-fermentation:
Sauerkraut is a naturally fermented cabbage that is usually served as a side dish or appetizer. Sauerkraut ferments from naturally present lactic acid bacteria. The microflora found naturally on cabbage changes throughout region, season, and cultivation patterns (Xiong et al. 2012). The typical form of sauerkraut contains cabbage and sometimes spices and garlic. Sauerkraut is usually immersed in a 6-8% salt solution (Xiong et al. 2012). The sauerkraut is left at room temperature to ferment for 6-12 days in a mason jar (Xiong et al. 2012.)
The natural bacteria present in the sauerkraut changes throughout the fermentation time and influences the final fermented product (Figure 1). The bacteria L. plantarum, L. casei and L. zeae are dominant species found in sauerkraut. In a study by Xiong et al. 2012, L. plantarum reached its maximum concentration on the second day and then decreased throughout the seven-day period, while L. casei reached its maximum on the third day. L. zeae survived the shortest amount of time because it is most sensitive to high acidity (Xiong et al. 2012). “The fermentation process was initiated by L. mesenteroides subsp. mesenteroides, followed by E. faecalis, L. lactis, L. zeae and finally terminated by L. plantarum and L. casei” (Xiong et al. 2012).
In sum, the population dynamic of spontaneous sauerkraut changes throughout the fermentation period. The knowledge of the population dynamic of microflora in sauerkraut can provide knowledge to help control the fermentation process. Using starter cultures can provide a more consistent population dynamic.
Figure 1. Changes in the flora of Lactobacilli during Chinese sauerkraut fermentation (◆ L. plantarum; ■ L. casei; ▲ L. zeae) (n = 6). Values below 1 indicate that the count was less than the detection limit (10 CFU/ml). Obtained from Xiong et al. 2012.
7. Sea vegetable Fermentation:
Fermenting seaweed could create another non-dairy alternative probiotic. While there are many fermented products out there, a number of these products are dairy based. The consumer demand for a non-diary based probiotic has increased due to lactose intolerance (Gupta et al. 2011). Fermented plant products offer a non-dairy alternative that contains probiotics with important health benefits.
The application and possibility of fermenting sea vegetables is a relatively new concept, as most of the fermented products in the food industry consists of terrestrial foods. Furthermore, seaweed contain unfavorable polysaccharides fermentation compounds, making it a topic in need of further research. “…brown algae contain alginate and fucoidan as major components. Red algae contain galactan (e.g. agar carrageenan) as a major component. Green algae and seagrasses contain cellulose and hemicellulose as major components (Uchida et al. 2013).” However recent research on brown and red sea vegetable species showed fermentation success by researching lactic acid bacteria starter cultures and other key variables.
Gupta et. al 2011 studied the fermentative capability of three Irish brown seaweeds: Himanthalia elongata, Laminaria digitata, and Laminaria saccharina by using the starter culture L. plantarum. Key variables that were studied were heat treatment of sea vegetables and aerobic/anaerobic conditions.
7.1 Heat Treatment:
Gupta et. al 2011 tested raw and heat treated sea vegetables in a preliminary study in order to determine the best growth mechanisms for lactic acid bacteria. For the heat treatment, sea vegetables were placed in an autoclave at 95 C for 15 min. The results from this preliminary study suggested that growth of lactic acid bacteria could not be sustained in any of the raw sea vegetable species, however in the heat treatment of L. digitata, and L. saccharina lactic acid bacteria growth did occur. Therefore, the heat treatment of sea vegetables could increase fermentative capability. The heat treatment resulted in an increase in the amount of sugars that could be readily used by L. plantarum (Gupta et al, 2011). Furthermore, heat treatment could help clean the microbial surface load on the sea vegetables and allow nutrients and sugars in the sea vegetables to be more available (Gupta et al, 2011).
Overall, this study showed that heat treated L. digitata and L. saccharina were suitable substrates for lactic acid fermentation by L. plantarum. The results showed that L. digitata obtained the highest cell populations, while L. saccharina achieved faster fermentation time because its maximum cell growth occurred in less time (Gupta et. al 2011).
7.2 Aerobic conditions:
Gupta et. al 2011 also tested the aeration conditions in regards to lactic acid bacteria growth and acetic acid production by changing the speed of agitation. Microaerophillic and aerobic conditions were tested and growth kinetics, such as the lag period and maximum specific growth rate of the L. plantarum were measured. Cultures that show accelerated growth during fermentation have more favorable growth conditions.
The agitation speed of the culture influenced the amount of lactic acid bacteria growth because when the agitation speed was increased, the maximum cell growth decreased. This is due to the different metabolic processes that occur from the presence of oxygen in fermentation. Homofermentative and hetermentative bacteria produce more acetic acid when oxygen is present (Gupta et. al 2011).
7.3 Fermentation formulation:
Ratanaburee et. al 2011 studied the use of L. plantarum as a seaweed starter culture by researching the optimal conditions and ingredients for producing a functional fermented red seaweed beverage. Dried Gracilaria fisheri, a red seaweed that is commonly found in Thailand, was used in this study because it contains carotenoids, polyphenols, and phenolic acid that can be beneficial for human consumption (Ratanaburee et. al 2011). Ratanaburee et. al 2011 studied four different fermented plant beverage formulations. The first formulation, treatment A, consisted of red seaweed, sugar, and water. Treatment B, was similar to treatment A, but had the addition of a 5% starter culture of L. plantarum. Treatment C was also similar to treatment A, however it included an increased sugar concentration and the addition monosodium glutamate (MSG). Treatment D was the same as treatment C, but had the addition of a 5% starter culture L. plantarum.
Fermenting seaweed has the potential to be a functional food because of the presence of γ-aminobutyric acid (GABA) in the product. GABA is often found in fermented foods because some lactic acid bacteria (such as Lactobacillus brevis, L. plantarum and Lactococcus lactis) have the ability to produce it. The functions of GABA have been known to prevent diabetes, inhibit the growth of cancer cells, and reduce hypertension (Ratanaburee et. al 2011). “GABA is a non-protein amino acid compound that is synthesized by decarboxylation of glutamic acid via the glutamate decarboxylase enzyme (Komatsuzaki et al. 2008)” Because of this process, MSG was added into some of the treatment beverage formulas to determine if it can increase the amount of GABA in these formulas (Ratanaburee et. al 2011).
Ratanburee et. al. 2011 discovered that there are several factors that can influence the quality of the finished fermented product such as: the addition of a starter culture, addition of MSG, and changing sugar concentrations (Ratanburee et. al. 2011). The treatments that were inoculated with a starter culture had a higher amount of beneficial microbes, total bacteria count (TBC), and LAB count after the fermentation period of 60 days. However, LAB remained the dominant bacteria in all treatments and almost all the bacteria that was present in the treatment was LAB. Ratanaburee et. al 2011 found that adding MSG influenced the GABA content because treatment D, the treatment with the added MSG, produced the highest amount of GABA during the fermentation period. However, the MSG treatments scored the lowest on a sensory test that measured flavor, odor, and color because of its salty taste. Furthermore, the third treatment did not undergo sensory evaluation due to a lower GABA production and a salty taste. Lastly, changing the sugar content showed that as the sugar content decreased the acidity level increased.
Further findings showed that yeast contamination was found in all treatments, a factor that can influence the microbial quality of a fermented product. In addition, yeast contamination can vary among the type seaweed, processing method, and the source of where the seaweed is found (Ratanburee et. al. 2011).
The findings by Ratanburee et al. 2011 show that fermentation of dried Gracilaria fisheri is possible. However, the balance of having a palatable product with high GABA content still remains in question. Adding MSG to seaweed fermentations results in an unpalatable product, despite the high GABA production. This research also showed that yeast contamination can be a problem during seaweed fermentation.
The research by Uchida et al. 2007 on the fermentation of the brown seaweed, Undaria pinnatifida, served to solve the problem of contamination in fermentation by determining how lactic acid bacteria could regulate the growth of contaminant bacteria. This research also provided alternatives to the problem of sterilizing seaweed. Sterilizing can destroy some of the nutritional properties and the appearance of seaweeds. Conversely, sterilizing seaweed is important to reduce the microbial load during fermentation. The appropriate inoculate species or salt content could help reduce the microbial load and omit the need to sterilize seaweed. Therefore, this research focused on the use of different inoculate species and the effect of salt in seaweed fermentations.
7.4 Inoculate species:
Uchida et al. 2007 studied fourteen different lactic acid bacteria strains to determine which strain could reduce the microbial load of fermentations. All the cultures that had no added inoculate spoiled, indicating that the addition of an inoculate is a necessary component to sea vegetable fermentation (Uchida et al. 2007). It was found that inoculates L. brevis, L. plantarum, L. casei, and L. rhamnosus showed the highest bacteria inhibition (Uchida et al. 2007). All bacteria species, besides L. brevis, were homofermenters and they all produced the highest quantity of lactic acid. The high acid production by these species lowered the pH of the fermented culture, most likely causing the successful inhibition by the aforementioned species.
The twenty-degrees Celsius temperature of the cultures that were studied could have played a role in the inhibition capabilities of these strains. The lower temperature of these cultures best represented the natural temperature of water and was “preferable for performing a large-scale fermentation of seaweed biomass at a low-energy cost” (Uchida et al. 2007).
7.5 Salt Content:
Uchida et al. 2007 researched the conditions of fermenting seaweeds by investigating the salt content, a variable that had never been tested before. Undaria powder cultures were made using a combination of water, 3.5% salt, inoculate, and cellulase. Similar cultures were made without the addition of salt. Cellulase was added as a pretreatment in the culture because previous findings by Uchida et al. 2007, showed a higher soluble sugar content and more successful ferment with the addition of cellulase. Cellulase allows for saccharification, meaning hydrolysis of polysaccharides to soluble sugars (Uchida et al. 2007). This can induce fermentation. Cellulase also helped avoid fermentation rotting (Uchida et al. 2007).
The presence of salt was responsible for inhibiting microbes, as cultures without salt grew contaminant bacteria that spoiled cultures. The concentration of salt added to a culture can affect the growth of lactobacillus starter cultures. Lactobacillus are not halotolerant and their growth is restricted as the salt concentration is increased above 5% (Uchida et al. 2007). It was found that salt water concentrations that ranged from 2.5-3.5% showed the most ideal fermentation conditions (Uchida et al. 2007).
The fermentation period of sea vegetables was determined based on the production of lactic acid, total acid, sugar consumption, and pH levels. It was found that many changes occur within seven days of the fermentation period.
Ratanburee et al. 2011 measured the fermentation of a red seaweed throughout the course of 60 days and found that most biochemical changes occurred within 7 days. It was found that the highest levels of lactic acid bacteria occurred within ten days of the fermentation period with a gradual decline thereafter. The total bacteria count displayed a similar trend, where almost all treatments showed the highest count within ten days. In addition, the total sugar decreased the most rapidly after 7 days, this also resulted in the increase of total acidity. The pH of the fermentation decreased the most rapidly within one day of the fermentation. After 60 days the pH in the tested treatments ranged from 3.2-3.8, with the initial pH range being 5-7.
In addition, similar findings by Uchida et al. 2007 determined that the culture period for a tested red seaweed as eleven days. The fermentation process took seven days based on lactic acid production and when the pH became constant and the microbial number increased. The microbial number increased from the first day to the fourth or sometimes until the seventh day of the study. After this time period, the microbial number gradually decreased while the pH stayed constant.
The key variables that influence sea vegetable fermentation are salt content, environmental parameters, temperature, and the pre-treatment of sea vegetables. While some of these variables have been studied, none of these studies have been done on Maine sea vegetables. Therefore, it is inconclusive if Maine sea vegetable can be fermented.
...(download the rest of the essay above)