1. |
- Jacobsen, Maria, et al.
(author)
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Nutritional and toxicological characteristics of Saccharina latissima, Ulva fenestrata, Ulva intestinalis, and Ulva rigida: a review
- 2023
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In: International Journal of Food Properties. - 1094-2912 .- 1532-2386. ; 26:1, s. 2349-2378
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Research review (peer-reviewed)abstract
- Nutrient and toxicant levels as well as their bioavailability in S. latissima and Ulva species (fenestrata, intestinalis, rigida) were reviewed. Nutritional quality was assessed by nutrient contribution to daily reference intake (DRI) per portion (5 g dry weight), nutrient density score NRF21.3, and comparisons to reference foods. Toxicological assessments comprised tolerable daily intake (TDI)-levels. Based on mean %DRI per portion, S. latissima and Ulva species were good sources (%DRI >15) of calcium, magnesium, iron, selenium, and vitamin B12. Mean %DRI was <10% for fiber, sodium, and protein. Toxicological concerns were mainly due to iodine (mean %TDI per portion: 3160% for S. latissima and 41–91% for Ulva species). Mean %TDIs for inorganic arsenic, cadmium, and lead were <20% for S. latissima and 9–97%, 6–15%, and 21–46%, for the selected Ulva species, respectively. Bioavailability data were scarce and is, together with nutritional impact of processing, an important aspect to address in future studies.
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2. |
- Sajib, Mursalin, 1987, et al.
(author)
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Pilot-Scale Ensilaging of Herring Filleting Co-Products and Subsequent Separation of Fish Oil and Protein Hydrolysates
- 2022
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In: Food and Bioprocess Technology. - : Springer Science and Business Media LLC. - 1935-5130 .- 1935-5149. ; 15:10, s. 2267-2281
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Journal article (peer-reviewed)abstract
- In this study, ensilaging of herring ( Clupea harengus ) flleting co-products was taken from lab-scale to pilot scale (1500 L) while monitoring the protein degree of hydrolysis (DH) and lipid oxidation. Subsequently, the possibility of recovering fish oil and protein hydrolysates using batch centrifugation at diferent g-forces/times was investigated. Around 38% DH was recorded after 2-day pilot-scale ensilaging of herring co-products at ambient temperature (i.e., ~22 °C), which was similar to the DH found in lab-scale (40% after 2 days; 22 °C). The lipid oxidation marker 2-thiobarbituric acid reactive substances (TBARS) reached 20 µmole TBARS/kg silage after 2-day ensilaging. Centrifugation of the silage at 3000–8500 ×g for 2–20 min revealed successful separation into fsh oil and protein hydrolysates. Heat-treating the silage (85 °C; 30 min) prior to centrifugation resulted in signifcantly higher oil and hydrolysates recoveries; the same being true for increased g-force. At 8500×g, the recovery of oil and hydrolysates were 9.7 and 53.0% w/w, respectively, from heat-treated silage, while recoveries were 4.1 and 48.1% w/w, respectively, from non-heat treated silage. At 4500×g, being a more scalable approach, corresponding numbers were 8.2 and 47.1% (w/w) as well as 2.0 and 40.2% (w/w). The recovered fsh oil contained 8% EPA and 11% DHA of total fatty acids. Free fatty acids (FFA), peroxide value (PV), p-anisidine value (p-AV), and total oxidation (TOTOX) values of oils were in the range of 4–7% (FFA), 3.6–3.7 meq/kg oil (PV), 2.5–4.0 (p-AV), and 9.9–11.1 (TOTOX), respectively, which were within the acceptable limits for human consumption specifed by the GOED voluntary monograph. The recovered protein hydrolysates contained peptides in the molecular weight range 0.3–6 kDa (~ 37%) and 11–34 kDa (~ 63%). Also, the remaining solids contained 15–17% (w/w) protein, having 44–45% essential amino acids. Overall, the results suggest that herring co-product silage is a valuable source of fsh oil and protein hydrolysates, paving the way for ensilaging based-biorefning of herring co-products into multiple products.
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3. |
- Stedt, Kristoffer, 1991, et al.
(author)
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Cultivation of seaweeds in food production process waters: Evaluation of growth and crude protein content
- 2022
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In: Algal Research. - : Elsevier BV. - 2211-9264. ; 63
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Journal article (peer-reviewed)abstract
- There is an increasing demand for sustainably produced, protein-rich, and nutritious food. Seaweeds are promising protein sources for the future if their protein content can be optimized, something which can be achieved by cultivation in elevated nutrient concentrations. Cultivation of seaweeds in integration with fish farms have received much attention lately, but using nutrient-rich process waters from other food industries as feed stock for seaweed has rarely been studied. Here, we demonstrate a simple and sustainable strategy to answer the increasing world demand for food rich in plant-based proteins by connecting food production process waters with seaweed cultivation. We compared growth rates and crude protein content of four different seaweed species, the brown species Saccharina latissima, and the green species Ulva fenestrata, Ulva intestinalis, and Chaetomorpha linum, when cultivated in two dilutions (providing 20 and 200 μM ammonium) of eight different process waters emerging from recirculating salmon aquaculture systems as well as from herring, shrimp and oat processing. Growth rates of the green seaweeds were up to 64% higher, and crude protein content was almost up to four times higher when cultivated in the food production process waters, compared to seawater controls. Growth rates were generally higher in presence of 20 μM compared to 200 μM ammonium, while crude protein content was either unaffected or positively affected by the increasing ammonium concentration. This study indicates the potential for cultivating seaweeds with food production process waters to generate additional protein-rich biomass while nutrients are being circulated back to the food chain. A new nutrient loop is thus illustrated, in which the costly disposal of food production process waters is instead turned into value by seaweed cultivation.
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4. |
- Stedt, Kristoffer, 1991, et al.
(author)
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Post-harvest cultivation with seafood process waters improves protein levels of Ulva fenestrata while retaining important food sensory attributes
- 2022
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In: Frontiers in Marine Science. - : Frontiers Media SA. - 2296-7745.
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Journal article (peer-reviewed)abstract
- Seaweed aquaculture can provide the growing human population with a sustainable source of proteins. Sea-based cultivation is an effective method for farming seaweeds on a large scale and can yield high biomass output. However, the quality and biochemical composition of the biomass is seasonally dependent, which limits the harvests to certain periods of the year. Here we show the possibility to extend the sea-based cultivation season of Ulva fenestrata when aiming for high protein levels, by post-harvest treatment in herring production process waters. We harvested U. fenestrata at an optimal period in terms of yield, but suboptimal in terms of protein content. We then cultivated the seaweed in onshore tank systems with the nutrient-rich process waters for 14 days. We monitored biomass yield, crude protein content, amino acid composition, and content of the health concerning metals arsenic, mercury, lead, and cadmium, as well as the sensory properties of the dried biomass. After cultivation in the process waters, biomass yields were 30 - 40% higher (210 – 230 g fresh weight) compared to in seawater (160 g fresh weight). Also, the crude protein and amino acid content increased three to five times in the process waters, reaching 12 - 17 and 15 – 21% dry weight, respectively. The protein enriched biomass followed food graded standards for heavy metal content, and consumption of the biomass does not exceed health based reference points. Additionally, no sensory attributes regarded as negative were found. This rapid, post-harvest treatment can help extend the cultivation season of sea-based seaweed farms, maximizing their output of sustainable proteins.
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5. |
- Trigo, João Pedro, 1995, et al.
(author)
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Effects of whole seaweed consumption on humans: current evidence from randomized-controlled intervention trials, knowledge gaps, and limitations
- 2023
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In: Frontiers in Nutrition. - 2296-861X. ; 10
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Research review (peer-reviewed)abstract
- Seaweed is often recognized for its potential health benefits, attributed to its abundance of dietary fibers, protein, and polyphenols. While human observational studies have shown promise, the collective evidence from human intervention trials remains limited. This narrative review aims to comprehensively analyze the effects of seaweed intake on humans, while critically assessing the methodology, including Cochrane risk-of-bias assessment. A search was conducted in online databases, including PubMed, Scopus, and Google Scholar, covering the period from 2000 to May 2023. The focus was on randomized controlled clinical trials (RCTs) evaluating the impact of whole seaweed, either consumed as capsules, integrated into food products or as part of meals. Various health outcomes were examined, including appetite, anthropometric measures, cardiometabolic risk factors, thyroid function, markers of oxidative stress, and blood mineral concentrations. Out of the 25 RCTs reviewed, the findings revealed limited yet encouraging evidence for effects of seaweed on blood glucose metabolism, blood pressure, anthropometric measures, and, to a lesser extent, blood lipids. Notably, these favorable effects were predominantly observed in populations with type-2 diabetes and hypertension. Despite most trials selecting a seaweed dose aligning with estimated consumption levels in Japan, considerable variability was observed in the pretreatment and delivery methods of seaweed across studies. Moreover, most studies exhibited a moderate-to-high risk of bias, posing challenges in drawing definitive conclusions. Overall, this review highlights the necessity for well-designed RCTs with transparent reporting of methods and results. Furthermore, there is a need for RCTs to explore seaweed species cultivated outside of Asia, with a specific emphasis on green and red species. Such studies will provide robust evidence-based support for the growing utilization of seaweed as a dietary component in regions with negligible seaweed consumption, e.g., Europe.
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6. |
- Trigo, João Pedro, 1995, et al.
(author)
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In vitro digestibility and Caco-2 cell bioavailability of sea lettuce (Ulva fenestrata) proteins extracted using pH-shift processing
- 2021
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In: Food Chemistry. - : Elsevier BV. - 0308-8146 .- 1873-7072. ; 356
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Journal article (peer-reviewed)abstract
- Seaweed is a promising sustainable source of vegan protein as its farming does not require arable land, pesticides/insecticides, nor freshwater supply. However, to be explored as a novel protein source the content and nutritional quality of protein in seaweed need to be improved. We assessed the influence of pH-shift processing on protein degree of hydrolysis (%DH), protein/peptide size distribution, accessibility, and cell bioavailability of Ulva fenestrata proteins after in vitro gastrointestinal digestion. pH-shift processing of Ulva, which concentrated its proteins 3.5-times, significantly improved the %DH from 27.7±2.6% to 35.7±2.1% and the amino acid accessibility from 56.9±4.1% to 72.7±0.6%. Due to the higher amino acid accessibility, the amount of most amino acids transported across the cell monolayers was higher in the protein extracts. Regarding bioavailability, both Ulva and protein extracts were as bioavailable as casein. The protein/peptide molecular size distribution after digestion did not disclose a clear association with bioavailability.
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7. |
- Trigo, João Pedro, 1995, et al.
(author)
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Mild blanching prior to pH-shift processing of Saccharina latissima retains protein extraction yields and amino acid levels of extracts while minimizing iodine content
- 2023
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In: Food Chemistry. - : Elsevier BV. - 0308-8146 .- 1873-7072. ; 404
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Journal article (peer-reviewed)abstract
- The seaweed Saccharina latissima is often blanched to lower iodine levels, however, it is not known how blanching affects protein extraction. We assessed the effect of blanching or soaking (80/45/12 °C, 2 min) on protein yield and protein extract characteristics after pH-shift processing of S. latissima. Average protein yields and extract amino acid levels ranked treatments as follows: blanching-45 °C ∼ control > soaking ∼ blanching-80 °C. Although blanching-45 °C decreased protein solubilization yield at pH 12, it increased isoelectric protein precipitation yield at pH 2 (p < 0.05). The former could be explained by a higher ratio of large peptides/proteins in the blanched biomass as shown by HP-SEC, whereas the latter by blanching-induced lowering of ionic strength, as verified by a dialysis model. Moreover, blanching-45 °C yielded a protein extract with 49 % less iodine compared with the control extract. We recommend blanching-45 °C since it is effective at removing iodine and does not compromise total protein extraction yield.
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8. |
- Trigo, João Pedro, 1995
(author)
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Seaweed as a sustainable source of food protein: maximizing seaweed protein content, protein recovery, and nutritional quality
- 2023
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Doctoral thesis (other academic/artistic)abstract
- This thesis focuses on utilizing seaweed, such as Saccharina latissima and Ulva fenestrata , as sustainable food protein sources to complement terrestrial protein currently limited by land and water supply. While seaweed holds promise, its protein content is lower than pulses and antinutrients reduce protein nutritional quality. Additionally, S. latissima often contains excessive iodine, necessitating post-harvest blanching. We aimed to produce protein-rich seaweed using food-process waters as nutrient sources; assess how blanching parameters impact downstream pH-shift-based protein extraction; create an efficient extraction method targeting aqueous-soluble and lipophilic proteins; and evaluate the influence of extraction on protein nutritional quality after in vitro digestion. When food-process waters, mostly herring-derived, were added separately to the cultivation media of tank-cultivated U. fenestrata , protein content increased 2.4-fold compared to seawater media, reaching 24% per dry weight (dw). Growth rates generally remained unaffected and S. latissima was incompatible with this new nutrient loop. Blanching sea-cultivated S. latissima at 45 or 80 °C for 2 minutes was equally effective at reducing iodine. However, biomass blanched at 45 °C provided higher protein extraction yields (23% vs. 14%). Iodine was still the limiting element for the daily adult consumption of extracts from blanched biomasses (0.5 g dw), though higher than extracts from crude biomass (0.1 g). Employing 0.1-0.5% aqueous Triton X-114 during protein extraction from U. fenestrata followed by alkaline extraction provided a 3.3-fold increase in extraction yields (23%) compared to two alkaline extraction cycles. In both protocols, proteins were concentrated via isoelectric precipitation. It was confirmed that Triton disintegrated membranes, targeting also lipophilic proteins. Digestibility of pH-shift extracts from U. fenestrata increased from 28% for crude biomass to 36%. Extraction also raised amino acid accessibility from 57% to 73%. When using the Caco-2 cell model, amino acids from U. fenestrata and extracts thereof were as bioavailable as casein. Altogether, we raised seaweed protein content by recycling nutrients currently lost during food processing, improved protein extraction yields, and proved that extracts have higher digestibility than crude seaweed. Based on theoretical estimations, seaweed can offer a modest contribution to sustainable food systems, though this relies on scaling up seaweed production volumes.
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