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Seaweed Polysaccharides (Agar, Alginate Carrageenan)
... The primary utilization of agar stems from its remarkable attributes in thickening and gelling. It can retain substantial quantities of soluble solids, including sugars, and elevated melting temperatures and its proficiency in preventing sugar crystallization, agar is widely desirable in the food industry, particularly for the preparation of icings and bakery glazes [81,88]. ...
... According to research, alginate exhibits potential as an appetite regulator and may have utility as a dietary supplement. Nevertheless, the integration of the substance mentioned above into breakfast bars does not show significant variances as a means of reducing appetite in comparison to the control group [81,114,124,129]. The efficacy of alginate as a coating film in cooked chicken nuggets was observed, resulting in enhanced heat distribution and reduced cooking duration [82,131,132]. ...
... Carrageenans and semi-refined carrageenans are utilized in the food industry because they gel, emulsify, thicken, and stabilize. Carrageenans are frequently utilized as a constituent in dairy commodities, particularly in frozen desserts like ice cream [58,81,90] and milk-based products [74,115]. According to the findings of some other studies, the shelf life of fresh chicken breasts increased by utilizing carrageenan as an encompass film or in bakery products like bread [138]. ...
Seaweed has different biologically active macromolecules, including polyphenols, fiber, proteins, and polysaccharides. Recent developments in seaweed bioactive compounds improved food packaging quality and functional properties and increased food production innovations and sustainability. Seaweed compounds are a good source of gelling, thickening, and emulsifying agents in food industrial products. Further Green Extraction methods are used for the extraction of bioactive compounds, these methods are environment friendly, with less time and high-yield production. Seaweeds incorporate antioxidants that reduce lipid oxidation, thus enhancing food's durability and nutritional value and reducing free radicals' occurrence and retard the growth of bacteria. Seaweed has increased its potential for antimicrobial packaging solutions. The manuscript explores the perspective for advancing seaweed-based films, involving property improvements, increased shelf life, and production scalability. Seaweed-based films offer sustainable packaging for fresh produce, seafood, bakeries, and confectionery products. Seaweed-derived bioactive compounds enhance the quality and safety of packaged food products and seaweed polysaccharides in food packaging are their biodegradability and environmental friendliness.
... spp. [3,4]. However, seaweeds produce hybrid structures of the kappa, iota, and lambda forms of carrageenans, which are composed D-galactopyranose residues bonded by regularly alternating α-(1 → 3) and β-(1 → 4) bonds [5]. ...
... Gel properties of phycocolloids are usually species-dependent and dictated by the environmental conditions and extraction and isolation methods of the polysaccharides. Conventional extraction methods generally include a washing step followed by pre-treatments (employing alkali (e.g., NaOH) or acidified water) and a final hot-water extraction [3]. Alkali treatment has commonly been carried out due to the reportedly weak gel properties of the gels extracted with hot water [12]. ...
... Galactomannans by themselves can form viscous solutions; however, they are also able to synergistically interact with other biopolymers. The synergistic effects between κ-carrageenan-galactomannan systems depend on the mannose/galactose ratio of the galactomannan backbone [3]. In these mixed systems, the mannose-free regions of the galactomannans are able to associate with carrageenan helices, leading to the formation of elastic and strong gels, offering the potential of improving food products and reducing production costs [18]. ...
Seaweeds, rich in high-value polysaccharides with thickening/gelling properties (e.g., agar, carrageenan, and alginate), are extensively used in the food industry for texture customization and enhancement. However, conventional extraction methods for these hydrocolloids often involve potentially hazardous chemicals and long extraction times. In this study, three red seaweed species (Chondrus crispus, Gelidium Corneum, and Gracilaria gracilis) commercialized as food ingredients by local companies were chosen for their native gelling biopolymers, which were extracted using water-based methodologies (i.e., (1) hydration at room temperature; (2) stirring at 90 °C; and (3) centrifugation at 40 °C) for production of sustainable food gels. The potential use of these extracts as bioinks was assessed employing an extrusion-based 3D printer. The present work aimed to study the gelation process, taken place during printing, and assess the effectiveness of the selected green extraction method in producing gels. To improve the definition of the printed gel, two critical printing parameters were investigated: the addition of locust bean gum (LBG) at different concentrations (0, 0.5, 1, 1.5, 2, and 2.5%) and printing temperature (30, 40, 60, and 80 °C). Rheological results from a controlled-stress rheometer indicated that gels derived from G. corneum and G. gracilis exhibited a lower gel strength (lower G′ and G″) and excessive material spreading during deposition (lower viscosity) than C. crispus. Thus, G′ was around 5 and 70 times higher for C. crispus gels than for G. corneum and G. gracilis, respectively. When increasing LBG concentration (0.5 to 2.5% w/w) and lowering the printing temperature (80 to 30 °C), an enhanced gel matrix definition for G. corneum and G. gracilis gels was found. In contrast, gels from C. crispus demonstrated greater stability and were less influenced by these parameters, showcasing the potential of the seaweed to develop sustainable clean label food gels. Eventually, these results highlight the feasibility of using algal-based extracts obtained through a green procedure as bioinks where LBG was employed as a synergic ingredient.
... Carrageenans find extensive use in the food industry due to their ability to gel, thicken, and stabilize food products [54]. The commercial forms of L-, κ-, and ι-carrageenans have been approved as food additives by regulatory bodies such as the Food and Drug Administration (FDA) and the European Food Safety Agency (EFSA) [55]. ...
... Water solubility is characteristic of all carrageenan variants, albeit their solubility in aqueous solutions is subject to influence from factors such as temperature, pH, ionic strength, and the presence of cations. The hydrophilic nature of carrageenans stems from the sulphate and hydroxyl groups, while their hydrophobic characteristics mainly arise from the 3,6-anhydro-α-D-galactopyranose units [54]. ...
... These polysaccharides can be derived from the cell walls of brown algae, including species such as Macrocystis pyrifera, Laminaria hyperborea, Ascophyllum nodosum, as well as various bacterial strains [81]. Alginate, derived from alginic acid and its derivatives and salts [54,82], accounts for 10% to 40% of the dry weight of untreated algae and comprises 30-60% of the total sugars in brown seaweeds [83]. Alginates are anionic linear polysaccharides present in significant amounts in brown seaweeds, constituting up to 40% of the dry weight, and they have been acknowledged for their capacity to create edible films. ...
Seaweeds are abundant sources of diverse bioactive compounds with various properties and mechanisms of action. These compounds offer protective effects, high nutritional value, and numerous health benefits. Seaweeds are versatile natural sources of metabolites applicable in the production of healthy food, pharmaceuticals, cosmetics, and fertilizers. Their biological compounds make them promising sources for biotechnological applications. In nature, hydrocolloids are substances which form a gel in the presence of water. They are employed as gelling agents in food, coatings and dressings in pharmaceuticals, stabilizers in biotechnology, and ingredients in cosmetics. Seaweed hydrocolloids are identified in carrageenan, alginate, and agar. Carrageenan has gained significant attention in pharmaceutical formulations and exhibits diverse pharmaceutical properties. Incorporating carrageenan and natural polymers such as chitosan, starch, cellulose, chitin, and alginate. It holds promise for creating biodegradable materials with biomedical applications. Alginate, a natural polysaccharide, is highly valued for wound dressings due to its unique characteristics, including low toxicity, biodegradability, hydrogel formation, prevention of bacterial infections, and maintenance of a moist environment. Agar is widely used in the biomedical field. This review focuses on analysing the therapeutic applications of carrageenan, alginate, and agar based on research highlighting their potential in developing innovative drug delivery systems using seaweed phycocolloids.
... Gel strength dari agar umumnya didefinisikan sebagai kuat tekan yang dibutuhkan untuk mematahkan gel. Gel strength terletak pada ikatan hidrogen yang terbentuk di antara rantai galaktan linier yang mendukung reversibilitas yang baik dengan suhu pembentukan gel sekitar 45ºC, serta suhu pelelehan gel sekitar 85ºC (Phillips dan Williams, 2009;Alba dan Kontogiorgos, 2018). ...
... Menurut Phillips dan Williams (2009), agar terdiri dari dua fraksi polisakarida utama yaitu agarose dan agaropectine. Perbandingan antara kedua fraksi bervariasi, tergantung pada jenis rumput laut dan kondisi isolasi (Alba dan Kontogiorgos, 2018). Pada ...
... yang pada awalnya tidak sesuai untuk produksi agar dikarenakan kualitas yang dihasilkan sangat buruk dengan gel strength yang rendah. Agarose merupakan fraksi dengan sedikit kandungan sulfat, memiliki kapasitas pembentukan gel yang tinggi serta tidak bermuatan (netral) (Alba dan Kontogiorgos, 2018). Agaropectine memiliki muatan, heterogen, mengandung sulfat yang cukup tinggi serta kapasitas pembentukan gel yang rendah (Alba dan Kontogiorgos, 2018). ...
Salah satu jenis rumput laut yang tumbuh secara alami di perairan Jawa Timur adalah Gracilaria sp. Rumput laut ini dapat diekstrak yang salah satu kandungannya adalah agar yang banyak diaplikasikan pada industri makanan dikarenakan sifat penebalan dan pembentukan gel yang baik. Proses pemutihan (bleaching) menjadi salah satu pengembangan dari penelitian rumput laut. Proses pemutihan dilakukan untuk memenuhi permintaan pasar dimana produk yang telah diputihkan dianggap memiliki kualitas yang baik, bebas dari kontaminan serta aman bagi manusia dan lingkungan. Penelitian ini bertujuan untuk mengetahui pengaruh metode pemutihan Gracilaria sp. berupa chemical bleaching dan photo bleaching terhadap karakteristik crude agar meliputi yield crude agar, gel strength dan whiteness level. Metode ekstraksi yang digunakan dalam penelitian ini adalah ekstraksi maserasi. Ekstraksi maserasi dilakukan menggunakan pelarut akuades pada suhu 85°C selama 1,5 jam. Crude agar yang didapatkan kemudian dianalisis karakteristiknya. Yield crude agar yang didapatkan pada metode chemical bleaching (CB) lebih tinggi jika dibandingkan dengan metode photo bleaching (PB). Pada hasil pengujian gel strength, metode photo bleaching (PB) memiliki gel strength yang lebih tinggi dibandingkan dengan variabel chemical bleaching (CB). Sedangkan pada hasil pengujian whiteness level, diketahui bahwa metode chemical bleaching (CB) memiliki hasil yang lebih tinggi jika dibandingkan dengan metode photo bleaching (PB).
... [62,63] Agar is a polysaccharide material that mainly comprises two polymers: first, agarose, a neutral, barely substituted, and strongly gelling macromolecule; and second, agaropectin, a charged, highly methoxyl-and sulfate-substituted macromolecule with weak gelling properties. [64,65] The strongly anionic carrageenan is a linear polysaccharide with a high content of ester sulfates of up to 40 %. Carrageenan can be obtained in various configurational types, the commercially most important ones are kappa, iota, and lambda. ...
... [66][67][68] All these polysaccharides are derived from either brown, red, or green seaweeds, where they are mainly produced as structural components in the cell walls. [64,65,69,70] Under certain conditions, such as in the presence of di-or multivalent cations, at specific pH values, or within distinctive temperature ranges, these biopolymers show gel-forming capacities. Their exact structure, molecular weights, yields, and purity, as well as mechanical properties can vary depending on the exact seaweed species these biopolymers are extracted from and the employed extraction method. ...
In the 1960s, the Swedish company Celloplast patented the first one‐piece plastic bag for packaging, and such plastic bags are heavily used all around the world until they are banned by some countries for environmental and sustainability reasons. Similarly, the EU banned certain single‐use plastic items in 2021—but food packaging is not part of this new regulation. And indeed, the majority of food packaging encountered today in the supermarket is still made from traditional, petrol‐based plastics. This review summarizes recent efforts in developing more sustainable alternatives to such petrol‐based food packaging. Different natural sources and production processes used to develop biodegradable, biopolymer‐based materials (bbMs) are discussed, which are categorized into natural bbMs, modified/plasticized bbMs, and plastic bbMs. An overview of the material properties of commercially available bbMs and bbMs developed in academic research projects is provided, and are compared with the properties of conventional, petrol‐based materials used for packaging. Furthermore, the role of academic and industrial contributors along the value chain of bbMs is highlighted and challenges that are responsible for the still limited occurrence of bbMs in daily lives are discussed.
... In those records, the compound was designated as 'kanten' [32]. Nowadays, agar is mostly extracted from seaweeds belonging to the two genera, Gelidium ( Figure 5) and Gracilaria ( Figure 6) [33], and due to its thermal reversibility, is primarily used for its thickening properties and serves as a plant-based alternative to animal-origin gelatine [34,35]. ...
... These phycocolloids are also used for immobilizing biocatalysts, in toothpaste as a stabilizer, in air freshener gels, in pet food, and in meat products [41]. The new applications of carrageenan in the food industry include its use as a protective coating on fresh-cut packaged food, wherein carrageenan acts as a gas barrier, changing the cut surfaces of the fruit and reducing respiration, which consequently slows down the discolorations and maintains texture throughout the shelf life [11,33]. ...
Seaweed polysaccharides are versatile both in their functions in seaweed physiology and in their practical applications in society. However, their content and quality vary greatly. This review discusses the main factors that influence the yield and quality of polysaccharides, specifically carrageenans and agars (sulfated galactans) found in red algae species (Rhodophyta). In addition, its historical, current, and emerging applications are also discussed. Carrageenan has been influenced mainly by photosynthetically active radiation (PAR) and nitrogen, while its relationship with temperature has not yet been replicated by recent studies. Agar’s seasonal trend has also been found to be more ambiguous than stated before, with light, temperature, nutrients, and pH being influencing factors. In this review, it is also shown that, depending on the compound type, seaweed polysaccharides are influenced by very different key factors, which can be crucial in seaweed aquaculture to promote a high yield and quality of polysaccharides. Additionally, factors like the extraction method and storage of polysaccharides also influence the yield and quality of these compounds. This review also highlights the drawbacks and inadequacy inherent from the conventional (or current) extraction technology approaches.
... In addition, the structure of the texturing agents added to the cheese models studied in this work could also be modified with heating. In fact, the gelation temperature of κ-carrageenans is between 35 and 65 • C, and agar-agar forms a gel at 30-35 • C [10,36]. Therefore, structural changes in both the initial cheese model components (proteins, fat) and texturing agents could explain the increase in hardness observed upon heating for 20 min. ...
... whereas the agar-agar cheese models were perceived as "rubbery" (Figure 3b). These results are in line with other scientific findings, as κ-carrageenan is known to form gels with a grainy and brittle texture, whereas agar-agar is known to form rigid gels [36,44,45]. Concerning the taste descriptors, κ-carrageenan cheese models were perceived as more "sour" and "salty" than agar-agar products. ...
Controlling flavor perception by analyzing volatile and taste compounds is a key challenge for food industries, as flavor is the result of a complex mix of components. Machine-learning methodologies are already used to predict odor perception, but they are used to a lesser extent to predict aroma perception. The objectives of this work were, for the processed cream cheese models studied, to (1) analyze the impact of the composition and process on the sensory perception and VOC release and (2) predict “fresh cream” aroma perception from the VOC characteristics. Sixteen processed cream cheese models were produced according to a three-factor experimental design: the texturing agent type (κ-carrageenan, agar-agar) and level and the heating time. A R-A-T-A test on 59 consumers was carried out to describe the sensory perception of the cheese models. VOC release from the cheese model boli during swallowing was investigated with an in vitro masticator (Oniris device patent), followed by HS-SPME-GC-(ToF)MS analysis. Regression trees and random forests were used to predict “fresh cream” aroma perception, i.e., one of the main drivers of liking of processed cheeses, from the VOC release during swallowing. Agar-agar cheese models were perceived as having a “milk” odor and favored the release of a greater number of VOCs; κ-carrageenan samples were perceived as having a “granular” and “brittle” texture and a “salty” and “sour” taste and displayed a VOC retention capacity. Heating induced firmer cheese models and promoted Maillard VOCs responsible for “cooked” and “chemical” aroma perceptions. Octa-3,5-dien-2-one and octane-2,3-dione were the two main VOCs that contributed positively to the “fresh cream” aroma perception. Thus, regression trees and random forests are powerful statistical tools to provide a first insight into predicting the aroma of cheese models based on VOC characteristics.
... Algal cell walls contain huge amount of polysaccharides (Alba and Kontogiorgos 2018), which are polymers of carbohydrates called polycarbohydrates. It has a lot of medicinal properties like antifungal, antibacterial, antiviral, antioxidant, antiinflammatory, anticancer, immunostimulatory, antidiabetic, antiproliferative, anticoagulant, anti-aging, and anti-glycatochlorella ellipsoidea interact with RAW264.7 cells of the macrophage murine, which triggers nuclear factor-kappa B (NF-B) and mitogen-activated protein kinase pathways and produce a large amount of diverse nitric oxide and cytokines. ...
Algae are rich sources of polysaccharides such as alginates, carrageenan, and agar. Commercial applications of algal biomass are primarily in energy production, new functional foods, and medicines. Soil algae help to fix atmospheric CO2 in soil and are primarily present on the surface of the soil to prevent soil erosion. Seaweed contains essential nutrients and bioactive compounds that have pending or potential applications in animal and human health and wellness. Various seaweed and seaweed extracts have been proven to have antibacterial, anti-diabetic, antiviral, antifungal, and antibacterial capabilities. Using algae for the extraction or bioconversion of pollutants such as nutrients and xenobiotics in polluted water and CO2 in polluted air currents is known as phycoremediation. Seaweed, which is commonly used in wastewater treatment, also helps to lower or eliminate hazardous heavy metal levels. The chapter delineates the contribution of algae toward sustainable development and commercial aspects of algae in fuel, medicine, and food applications.
... The yields of HWE1 Sc1021 and pH 9 Sc1021 were not significantly different. The pH did not seem to have a significant influence on the extraction yield, contrary to the effect on alginate yield, which requires careful monitoring of pH conditions [27]. An alkali treatment (1% KOH) was also tested in a previous study and led a polysaccharide yield of 25.8% [7]. ...
Red seaweed carrageenans are frequently used in industry for its texturizing properties and have demonstrated antiviral activities that can be used in human medicine. However, their high viscosity, high molecular weight, and low skin penetration limit their use. Low-weight carrageenans have a reduced viscosity and molecular weight, enhancing their biological properties. In this study, ι-carrageenan from Solieria chordalis, extracted using hot water and dialyzed, was depolymerized using hydrogen peroxide and ultrasound. Ultrasonic depolymerization yielded fractions of average molecular weight (50 kDa) that were rich in sulfate groups (16% and 33%) compared to those from the hydrogen peroxide treatment (7 kDa, 6% and 9%). The potential bioactivity of the polysaccharides and low-molecular-weight (LMW) fractions were assessed using WST-1 and LDH assays for human fibroblast viability, proliferation, and cytotoxicity. The depolymerized fractions did not affect cell proliferation and were not cytotoxic. This research highlights the diversity in the biochemical composition and lack of cytotoxicity of Solieria chordalis polysaccharides and LMW fractions produced by a green (ultrasound) depolymerization method.
... Carrageenans are divided into three different types, which are kappa (κ), iota (ι) and lambda (λ) carrageenan [13]. Iota-carrageenan forms soft and elastic gels that are resistant to freezing and thawing [14], and in the presence of calcium ions forms thermoreversible gels. Pectin is a water-soluble polysaccharide that is extracted from plant cell walls [15]. ...
The aim was to investigate the influence of different calcium salts and gelation times on the structural-mechanical parameters of a pear composite jellies. Calcium citrate and calcium lactate with a concentration of 0.6 % and 1.2 % were used as sources of calcium ions for the gelling time of 24 and 48 h. The changes in the structural-mechanical properties of the jellies were determined from the obtained typical curves through a penetration test using a texture analyzer. The increase in the concentration of calcium ions led to the increasing values of the structuralmechanical parameters of the fruit jellies, except for adhesiveness and rupture deformation. The shape of the penetration curves was determined to a greater extent by the type and concentration of calcium salts and to a lesser extent by the gelation time. The Pearson correlation coefficients for the compressive stress, deformation force and firmness increased compared to the other structural-mechanical properties with an increase in the gelation time and the concentration of calcium salts.
... They have also been employed as a new food due to their polymers, such as carrageenan, agar, and alginate, as well as their gelling, emulsifying, and thickening capabilities [14,15]. ...
Seaweeds have been utilized for millennia in Asian countries, although they have only more recently become popular in Western society. They began to be used in ancient times because of their long-term properties and, nowadays, seaweeds are being targeted as a potential tool to combat climate change. There are not many laws governing seaweeds because they have just lately been utilized as food. However, guidelines are being developed to regulate their manufacture and use. Because of seaweed's tendency to accumulate components, whether helpful or poisonous, limited doses of certain substances have been established to prevent consumer overdosage. Aside from chemical safety, microbiological safety is important for people, and preventing any pathogen from spreading and infecting seaweeds is critical. As a result, systems and ways to safeguard consumers must be developed. Because various seaweed species have varied compositions, certain seaweeds may be safer nutraceuticals than others. To ensure the safety of seaweed-based food items, the HACCP (Hazard Analysis Critical Control Point) system needs to be used. The majority of seaweeds consumed come from aquaculture; however, others come from wild harvesting. To ensure the success of the cultures, the waters must be tested for chemicals and biological risks, as well as for the pH, salinity, and temperature. Seaweeds have enormous promise in many industries, but in the food industry, they are beginning to play a major role, and seizing the chances to produce innovative, safe, and sustainable food sources is strongly advised. This critical review investigates the real potential of seaweed as a human food source and as a nutraceutical solution. This review also focuses on the usage of seaweed as a food product and the procedures required to prepare it. In addition, it compiles information on the applicable legislation and regulations, and it addresses the lengthy road that has to be traveled to increase human well-being by employing a new food source in a controlled manner while simultaneously reducing the human population's health problems.
... "Alginate" refers to the salts of alginic acid, but it is also utilized to describe all derivatives of alginic acid and alginic acid itself. However, the well-known, main commercial form of alginate is the sodium alginate [1,2]. Commercially available alginate is extracted from several species of algae such as Laminaria Macrocystis, Sargassum, Ascophyllum, Lessonia, Eclonia, and Durvillea [3,4]. ...
Alginate, categorized as a natural-based biodegradable polymer, stands out for its inherently exclusive properties. Although this unique polymer is widely processed using film, coating, and membrane technologies for different usage areas, textile applications are still limited. This study aims to compile promising approaches that will pave the way for the use of wet-spun alginate filaments in textile applications. In this regard, this study provides information about the molecular structure of alginate, the gel formation mechanism, and cross-linking using different techniques. Our literature review categorizes parameters affecting the mechanical properties of wet-spun alginate filaments, such as the effect of ion source and spinning dope concentration, needle diameter, temperature, and coagulants. Following this, a detailed and comprehensive literature review of the various approaches, such as use of additives, preparation of blended filaments, and grafted nanocrystal addition, developed by researchers to produce composite alginate filaments is presented. Additionally, studies concerning the use of different cations in the coagulation phase are reported. Moreover, studies about the functionalism of wet-spun alginate filaments have been offered.
... Additionally, their unique physicochemical characteristics, particularly their ability to form hydrogels, make them valuable additives in cosmetical formulations [64]. These polysaccharides serve versatile roles in skincare products, acting as emulsifiers, stabilizers, and viscosity-controlling agents, thereby enhancing both the efficacy and stability of the final product [68]. This multifunctional nature underscores the immense potential of macroalgae-derived polysaccharides in advancing cosmetical formulations for improved skincare outcomes. ...
Amidst the ever-evolving landscape of cosmetics, algae and their derived products have captured substantial worldwide interest, heralding a new era of innovation and sustainability in beauty products. Cosmetic formulations are witnessing an escalating incorporation of extracts from algal biomass owing to the diverse metabolites making them ideal for studying physiologically active components with unique biochemical properties. The concept of algal biorefinery plays a pivotal role in this context, as it integrates processes to convert algal biomass into a spectrum of valuable products, maximizing resource efficiency and sustainability. Research has proven that the rich and diverse pool of bioactive compounds in algae holds promise for novel nutraceutical, pharmaceutical, and cosmeceutical products. In marine brown algae, compounds like fucoxanthin, polysaccharides, MAAs, and phlorotannins have a variety of functions to combat ultraviolet radiation and protect human skin. Phlorotannins, for instance, contribute to sunscreen and antioxidant properties. The sea environment, teeming with physiologically essential substances, provides an array of cosmeceutical ingredients. Algae also house nutraceutical compounds like polyphenols, carotenoids, fucoidan, alginate, peptides, terpenoids, and polyunsaturated fatty acids, engaging in various biological activities. Algal compounds are emerging as viable alternatives, showcasing beneficial effects even with prolonged use and diverse algae species find widespread application in addressing skin disorders, serving as moisturizers, texture enhancers, sunscreens, and anti-wrinkling agents. This review delves into the bioactive components sourced from algae, especially seaweed and diatoms, unveiling their potential in anti-aging, photo-protection, and skin whitening. The discourse encompasses current applications, challenges, and prospects, highlighting the role of algal biorefinery in providing a sustainable and innovative future for skincare solutions.
... The unique properties of seaweed, such as its gelling ability, bioactive compounds, and texture-enhancing qualities, make it a valuable ingredient in the food industry. Seaweed extracts are used as thickeners, stabilizers, and emulsifiers in a wide array of products, from ice cream to salad dressings and carbonated beverages (Alba and Kontogiorgos, 2019). ...
Seaweed, often considered an overlooked resource, are marine algae with many applications in various industries. The many species of seaweed possess a range of nutritional values, environmental benefits, and their versatility make them an attractive subject of research and development. One promising method for preserving and utilising seaweed effectively is freeze drying. This review explores the world of seaweed, its properties, applications, and the potential of freeze-drying techniques in harnessing the above benefits. The review examines the freeze-drying process and discusses its applicability and advantages in preserving seaweed as a sustainable resource. The discussion also includes the diverse uses of seaweed, from culinary applications to pharmaceuticals and beyond, highlighting the potential of freeze-drying to unlock seaweed’s full potential
... Furthermore, bacteria have the potential of synthesizing enzymes such as agarases, amylases, phosphatases, esterases, β-galactosidases and cellulases capable of degrading a large variety of polysaccharides (Comba-González et al. 2016). These bacterial enzymes degrade the seaweeds to produce useful hydrocolloids such as alginate, agar and carrageenan often used in medicine, pharmaceutical and food industries (Alba and Kontogiorgos 2018). The epiphytic bacteria also secrete an array of antibiotic compounds which can be used in the production of antibacterial drugs for treating diverse diseases (Chellaram et al. 2013;Srilekha et al. 2017;Stincone and Brandelli 2020). ...
Seaweed associated bacteria can be exploited for sustainable production and conservation of seaweeds, although limited information exists in several coastal waters in West Africa. Here, the diversity and abundance of bacteria on five seaweeds, Sargassum vulgare, Padina durvillaei, Hydropuntia dentata, Hypnea musciformis and Ulva fasciata, and surrounding seawaters
across five coastal sites in the Central and Western regions of Ghana were investigated. Biochemical tests and MALDI–TOF identification system were used to determine the bacteria diversity and abundance on the seaweeds and seawater. A total of 530 bacterial isolates, belonging to 28 species (and mostly Proteobacteria and Firmicutes) were identified. A higher diversity of bacteria species was found associated with the seaweeds (83%) than in seawater (17%). Bacterial composition was similar among taxonomically-related seaweeds. The brown (S. vulgare) and red (H. musciformis) seaweeds recorded the most and least
diverse bacterial assemblage, respectively. Seasonally, bacterial diversity and abundance were marginally higher in the wet season. The study provides important baseline information on the spatial, temporal and taxonomic distribution of bacteria associated with
commercially valuable seaweed species in the coastal areas of Ghana. The results are also important for the sustainable exploitation and conservation of these important macroalgae
in Ghana and elsewhere.
... The total sugar content of P. dioica and G. gracilis were 30% and 27%, respectively. These seaweeds showed a sugar composition common for agar-producing red algae, with galactose as the main sugar residue (54 mol% and 34 mol%, respectively), as well as the presence of 3,6-anhydrogalactose (14 mol% and 25 mol%, respectively) and a naturally methyl-esterified sugar, 6-O-Me-galactose (11 mol% and 7 mol%, respectively) [63]. The complete results are shown in Table 4. Studies have been demonstrating the tremendous probiotic effects of galactose and some of its degradation products such as 3,6-anhydrogalactose and 6-O-Me-galactose [64,65]. ...
In this study, the chemical composition and antioxidant profile of five edible macroalgae, Fucus vesiculosus, Palmaria palmata, Porphyra dioica, Ulva rigida, and Gracilaria gracilis, cultivated in fully controlled closed systems, were determined. Protein, carbohydrates, and fat contents ranged between 12.4% and 41.8%, 27.6% and 42.0%, and 0.1% and 3.4%, respectively. The tested seaweeds presented considerable amounts of Ca, Mg, K, Mn, and Fe, which reinforce their favorable nutritional profile. Regarding their polysaccharide composition, Gracilaria gracilis and Porphyra dioica were rich in sugars common to agar-producing red algae, and Fucus vesiculosus was composed mainly of uronic acids, mannose, and fucose, characteristic of alginate and fucoidans, whereas rhamnose and uronic acid, characteristic of ulvans, predominated in Ulva rigida. Comparatively, the brown F. vesiculosus clearly stood out, presenting a high polysaccharide content rich in fucoidans, and higher total phenolic content and antioxidant scavenging activity, determined by DPPH and ABTS. The remarkable potential of these marine macroalgae makes them excellent ingredients for a wide range of health, food, and industrial applications.
... Structure and gelling mechanism of agarose[7]. ...
Numerous compounds present in the ocean are contributing to the development of the biomedical field. Agarose, a polysaccharide derived from marine red algae, plays a vital role in biomedical applications because of its reversible temperature-sensitive gelling behavior, excellent mechanical properties, and high biological activity. Natural agarose hydrogel has a single structural composition that prevents it from adapting to complex biological environments. Therefore, agarose can be developed into different forms through physical, biological, and chemical modifications, enabling it to perform optimally in different environments. Agarose biomaterials are being increasingly used for isolation, purification, drug delivery, and tissue engineering, but most are still far from clinical approval. This review classifies and discusses the preparation, modification, and biomedical applications of agarose, focusing on its applications in isolation and purification, wound dressings, drug delivery, tissue engineering, and 3D printing. In addition, it attempts to address the opportunities and challenges associated with the future development of agarose-based biomaterials in the biomedical field. It should help to rationalize the selection of the most suitable functionalized agarose hydrogels for specific applications in the biomedical industry.
... λ-carrageenan is especially interesting in terms of its structure and possible applications. It is mainly isolated from red seaweed Gigartina skottsbergi and Sarcothalia crispate [203]. It practically has no anhydro-oxygen bridge residues; therefore, it does not form a helix structure. ...
Growth factors are a class of proteins that play a role in the proliferation (the increase in the number of cells resulting from cell division) and differentiation (when a cell undergoes changes in gene expression becoming a more specific type of cell) of cells. They can have both positive (accelerating the normal healing process) and negative effects (causing cancer) on disease progression and have potential applications in gene therapy and wound healing. However, their short half-life, low stability, and susceptibility to degradation by enzymes at body temperature make them easily degradable in vivo. To improve their effectiveness and stability, growth factors require carriers for delivery that protect them from heat, pH changes, and proteolysis. These carriers should also be able to deliver the growth factors to their intended destination. This review focuses on the current scientific literature concerning the physicochemical properties (such as biocompatibility, high affinity for binding growth factors, improved bioactivity and stability of the growth factors, protection from heat, pH changes or appropriate electric charge for growth factor attachment via electrostatic interactions) of macroions, growth factors, and macroion-growth factor assemblies, as well as their potential uses in medicine (e.g., diabetic wound healing, tissue regeneration, and cancer therapy). Specific attention is given to three types of growth factors: vascular endothelial growth factors, human fibroblast growth factors, and neurotrophins, as well as selected biocompatible synthetic macroions (obtained through standard polymerization techniques) and polysaccharides (natural macroions composed of repeating monomeric units of monosaccharides). Understanding the mechanisms by which growth factors bind to potential carriers could lead to more effective delivery methods for these proteins, which are of significant interest in the diagnosis and treatment of neurodegenerative and civilization diseases, as well as in the healing of chronic wounds.
... Fucoidan is sulfated and mostly contain α-L-fucose. Depending on season, weather and extraction method, fucoidans constitute of total 20% of brown seaweed dry weight (Alba & Kontogiorgos, 2018;Senturk Parreidt, Müller, & Schmid, 2018;Setyawidati et al., 2018). Table 1 shows a brief overview of various type of seaweed polysaccharides-based edible packaging films. ...
Background
Novel innovative approaches like edible films have huge potential to be used in food contacting materials due to their positive impacts on ecological problems and other unique properties. Seaweed-based biopolymers can be an excellent and cost-effective source for bio-based polymers. Moreover, to impart functionality in biopolymers-based packaging the addition of essential oils (EOs) can be an eco-friendly and safe alternative to synthetic preservatives. With increasing interest in the use of bioactive compounds like EOs in biodegradable packaging materials, food packaging plays a key role in the preservation of food against environmental factors.
Scope and approach
This study reviewed a comprehensive summary of seaweed-based polymers sources and their derivatives, and production methods of edible seaweed-biobased films incorporated various EOs and characterization of their properties, EOs and their structure, and more. Edible seaweed-based films could be produced both independently or using its derivatives like agar, carrageenan, furcellaran, and alginate. Seaweed biobased films have more advantages over other polymers or biopolymers. They are edible, cheap, grow rapidly, biocompatible, non-toxic, and can be easily cultivated.
Key findings and conclusions
The seaweed-based functional films due to their superior features utilize in edible films for food packaging materials. Incorporation of EOs in seaweed-based biopolymers as natural additives with high antimicrobial, and antioxidant properties fulfil a key factor in the forming of edible functional active packaging materials with superior performances to extend the shelf-life of different packed foods. In addition, addition of EOs improve mechanical strength, hydrophobicity, UV-light barrier properties, and thermal properties of seaweeds-based films.
... The accelerated growth of plant-based meat, eggs, and dairy signals a growing global demand for more-sustainable alternatives to conventional products. The macroalgae-based bioeconomy can play a vital role in providing sustainable food (Cai et al., 2021), animal feed (Seghetta et al., 2017), pharmaceuticals, fertilizers (Seghetta et al., 2016) and hydrocolloids (alginates, agar and carrageenan) (Alba and Kontogiorgos, 2019). The comparative advantages of macroalgae are the much higher biomass productivity than that of terrestrial plants (Casoni et al., 2020), while not competing for land or freshwater , with a potential for carbon sequestration (Krause-Jensen and Duarte, 2016). ...
The last years have seen the emergence of the bioeconomy. Assessment of these new technologies is a significant challenge. We develop a unique dynamic programming framework to assess the value of the investment in a multi-stage supply chain with the production of bio-feedstock and its processing into multiple outputs. The system allows for adaptive learning in all supply chain stages, which creates a positive learning effect of cooutputs. We apply the framework to macroalgae (seaweed) farming and biorefinery processing into proteins and sugars for the Philippines and Ireland as representatives of developing and developed economies with emerging supply chains. We run Monte Carlo simulations to analyze the uncertainty of learning and prices. The key results indicate that the macroalgae sector that builds on traditional technologies is quite viable. Developing a new algae industry that generates proteins and other high-value products requires significant investment and depends on the dynamics of learning and prices. Even though the production of high-value chemicals is not yet viable, it gains profitability potential from learning of feedstock farming that is currently produced for the lower value application. The learning is much more valuable in feedstock production and processing into proteins than low-value chemicals currently produced (carrageenan).
available here: https://www.sciencedirect.com/science/article/pii/S0921800923000447?dgcid=author
... It significantly contributes to improving the properties of incorporated therapeutic substances, increases bioavailability and durability, and prolongs the release of bioactive ingredients at the target site. In addition, carrageenan also has antioxidant, anticarcinogenic, anticoagulant, and immunomodulatory properties [61,[238][239][240][241]. ...
Biopolymeric nanoparticles are gaining importance as nanocarriers for various biomedical applications, enabling long-term and controlled release at the target site. Since they are promising delivery systems for various therapeutic agents and offer advantageous properties such as biodegradability, biocompatibility, non-toxicity, and stability compared to various toxic metal nanoparticles, we decided to provide an overview on this topic. Therefore, the review focuses on the use of biopolymeric nanoparticles of animal, plant, algal, fungal, and bacterial origin as a sustainable material for potential use as drug delivery systems. A particular focus is on the encapsulation of many different therapeutic agents categorized as bioactive compounds, drugs, antibiotics, and other antimicrobial agents, extracts, and essential oils into protein- and polysaccharide-based nanocarriers. These show promising benefits for human health, especially for successful antimicrobial and anticancer activity. The review article, divided into protein-based and polysaccharide-based biopolymeric nanoparticles and further according to the origin of the biopolymer, enables the reader to select the appropriate biopolymeric nanoparticles more easily for the incorporation of the desired component. The latest research results from the last five years in the field of the successful production of biopolymeric nanoparticles loaded with various therapeutic agents for healthcare applications are included in this review.
Obtaining seaweed-based products has been outlined as an eco-friendly alternative to the conventional use of fertilizers and pesticides, avoiding its impact on the environment and limiting the dependence on nonsustainable resources. Incorporating new eco-friendly alternatives is crucial in integrated agriculture, especially in organic farming, where only a limited number of crop management products are allowed. Seaweed-based products can enhance plant growth and health in numerous ways, which depend on their specific application strategy and pursued effect, these can be grouped into three major sections according to their properties: (i) as a fertilizer and organic amendment, (ii) as a soil quality improver, and (iii) as a plant biostimulant.
The remainder of this chapter will discuss the main advancements and challenges in this field of research focusing on (1) the agronomic interest of seaweed, (2) seaweed in agronomic soils, (3) seaweed as plant biostimulants, (4) the regulatory framework, (5) seaweed as an agricultural input and its applications, (6) nondesired effects, (7) science gaps, and (8) economic viability.
The increasing demand for plastic and its products worldwide has resulted in a serious pollution issue with plastic trash, or “white pollution,” which persists in the environment for centuries before degrading. The demand for synthetic plastics derived from petrochemicals can be replaced by bioplastics, which can be used as an alternate source of plastic. Seaweeds or macroalgae have a huge acceptance among all other renewable resources as a source of bioplastics as they have high polysaccharide content, no freshwater and arable land requirements, limited nutrient requirements, and higher growth rates compared to terrestrial plants. Although there are several conventional methods for extracting seaweed hydrocolloids, increased demand has highlighted some of these techniques’ shortcomings, most notably in terms of consistency and efficiency of the final product. “Green extraction” techniques have demonstrated great potentiality (reproducible, faster, and environmentally friendly) for increasing production in an economical manner. Nonetheless, this chapter covers the present status, progress, limitations, and future prospects of seaweeds to better understand their potential as a resource for bioplastic synthesis in the near future.
The global seaweed market has been experiencing significant growth in recent years due to the increasing demand for seaweed-based products in various industries. It is influenced by several factors, including increasing consumer awareness of the nutritional and health benefits of seaweeds, growing demand for natural and sustainable products, and advancements in seaweed cultivation techniques. Due to their large biomass yields and fast growth rate, seaweeds have gained much attention as promising biopower and biomaterial feedstocks nowadays. Managing residual aquatic seaweed biomass in a sustainable and cost-effective manner requires a comprehensive approach that considers both environmental considerations and economic feasibility. In comparison to terrestrial crops previously considered as favorable feedstocks, macroalgae offer certain advantages in the biorefinery because the latter facilitates the extraction of different constituents ensuring full utilization of the biomass and generating fewer residues through a succession of steps. Thus, an interest in macroalgae biorefinery is increasing since it would solve both environmental and economic drawbacks of terrestrial biomass biorefinery. However, seaweed biorefinery concept is more recent and less mature than from terrestrial biomass. It means that the technologies applied for one could not be efficient for seaweeds and new developments need to be explored for the full utilization of macroalgae. Several strategies are presented in this chapter, and based on can be achieved a balance between sustainable management of residual seaweed biomass and cost-effective utilization, ensuring the long-term viability of seaweed as a valuable resource. However, with ongoing research and advancements in technology, seaweed biorefineries have a promising future in contributing to sustainable industries and addressing environmental and societal challenges. The concept of seaweeds biorefinery aligns with the principles of the biobased economy, which seeks to replace fossil-based products with sustainable alternatives. It promotes resource efficiency, reduces greenhouse gas emissions, and contributes to the development of a more sustainable and circular economy.
Biopolymers are a versatile and diverse class of materials that has won high interest due to their potential application in several sectors of the economy, such as cosmetics, medical materials/devices, and food additives. In the last years, the search for these compounds has explored a wider range of marine organisms that have proven to be a great alternative to mammal sources for these applications and benefit from their biological properties, such as low antigenicity, biocompatibility, and biodegradability, among others. Furthermore, to ensure the sustainable exploitation of natural marine resources and address the challenges of 3R’s policies, there is a current necessity to valorize the residues and by-products obtained from food processing to benefit both economic and environmental interests. Many extraction methodologies have received significant attention for the obtention of diverse polysaccharides, proteins, and glycosaminoglycans to accomplish the increasing demands for these products. The present review gives emphasis to the ones that can be obtained from marine biological resources, as agar/agarose, alginate and sulfated polysaccharides from seaweeds, chitin/chitosan from crustaceans from crustaceans, collagen, and some glycosaminoglycans such as chondroitin sulfate and hyaluronic acids from fish. It is offered, in a summarized and easy-to-interpret arrangement, the most well-established extraction and purification methodologies used for obtaining the referred marine biopolymers, their chemical structure, as well as the characterization tools that are required to validate the extracted material and respective features. As supplementary material, a practical guide with the step-by-step isolation protocol, together with the various materials, reagents, and equipment, needed for each extraction is also delivered is also delivered. Finally, some remarks are made on the needs still observed, despite all the past efforts, to improve the current extraction and purification procedures to achieve more efficient and green methodologies with higher yields, less time-consuming, and decreased batch-to-batch variability.
Graphical Abstract
Marine algae are thought to be a source of various metabolites that have a wide range of positive effects on human health. The pharmacological properties of algal metabolites, including their antioxidant, anti-inflammatory, cholesterol homeostasis, protein clearance, and anti-amyloidergic effects, lend credence to their protective efficacy against oxidative stress, neuroinflammation, mitochondrial dysfunction, and impaired proteostasis, all of which are involved in the pathophysiology of neurodegenerative disorders. There are currently no clinical trials on the effects of marine algae on neuroinflammation; however, considering the significant biological activities that have been established by in vitro and animal research, we expect that there will be clinical trials on this topic in the not-too-distant future. The most recent and important findings on the potentially neuroprotective effects of the anti-inflammatory properties of marine algae were chosen for this study. Next, we conducted a literature review on the neuroprotective potential of algal compounds, along with the underlying pharmacological mechanism, and finally, we evaluated recent advances in therapeutics.
In modern times, the plastic industry is significantly responsible for the large quantities of plastic that end up in water bodies and land. Every year, tons of plastic waste are scattered into the oceans, causing widespread environmental pollution, and disrupting ecosystems. As the need to reduce the usage of petroleum-based plastics grows, researchers are exploring alternative sources of raw materials that possess plastic-like properties but are biodegradable and non-toxic to the environment and human health. The development of biodegradable and bio-based polymers is gaining traction in the market. Some seaweed-based packaging that has already been developed demonstrates excellent mechanical properties, such as tensile strength, elongation at break, thermal resistance, and water vapor permeability, comparable to traditional petroleum-based plastics. The addition of other biopolymers, nanoparticles, or natural active agents improves these features. Seaweed polysaccharides exhibit various biological activities, which open the possibility of creating “active packaging” with antioxidant, antimicrobial, anticarcinogenic, and photoprotective properties that can help preserve the freshness of packaged food or pharmaceuticals. This chapter aims to present the role of seaweeds and algal bioactive compounds in the production of bio-packaging biodegradable and plastic-free.
This study aims to determine the best coffee juice jelly formulation using various concentrations of gelatin and xanthan gum, and evaluating the properties of each formula. The study used factorial experiments with 2 factors, 3 levels and 2 replicates. This approach allowed for the detection of the main and simple effects of each level, facilitating the analysis of variable impacts.The factors were Gelatin (9%; 10%; and 11%) and Xanthan Gum (1%; 2%; and 3%). The parameters for assessment were moisture content, ash content, texture, sugar content, fat content, caffeine content and organoleptics. The best treatment was selected based on the average acceptance of panelists on product quality. The best coffee juice jelly praline was made using 11% gelatin and 3% xanthan gum. It had 14.17% moisture and 0.32% ash content. For dark chocolate praline candy with coffee juice jelly candy filler, 10% gelatin and 2% xanthan gum was preferred by 40 respondents. It had 82.71% total sugar, 35.55% fat content, and 15% caffeine content.
In the boundless realm of scientific exploration, the book is about to delve into
stands as a testament to the ceaseless pursuit of knowledge in the chemical and
biological sciences. "Advances in Chemical and Biological Sciences" serves as a compass
guiding you through the intricate landscapes of molecules, cells, and the fascinating
interplay between the two.
As we embark on this intellectual journey, it's crucial to recognize the collective
efforts of brilliant minds whose tireless curiosity has fueled the progress documented
within these pages. The preface of this book is not just an introduction; it's an ode to the
insatiable human spirit that propels us to unravel the mysteries of the microscopic and
the macroscopic.
Within these chapters, you'll witness the marriage of theory and
experimentation, the fusion of innovation and tradition, all converging to push the
boundaries of our understanding. The frontiers of chemical and biological sciences are
not static; they are dynamic, ever-evolving landscapes where each discovery begets new
questions, and each answer opens the door to uncharted territories.
As you immerse yourself in the narratives penned by experts in their respective
fields, anticipate revelations that spark excitement, challenge preconceptions, and
inspire further inquiry. The pages ahead are not just a compilation of facts and figures
but a tapestry woven with the threads of intellectual curiosity, persistence, and the joy
of unraveling the secrets that nature has carefully guarded.
"Advances in Chemical and Biological Sciences" is not merely a book; it's a
rendezvous with the forefront of scientific inquiry. So, let the pages turn, let the words
unfold, and may your understanding of the chemical and biological world be forever
enriched
Bifidobacterium species are essential members of a healthy human gut microbiota. Their presence in the gut is associated with numerous health outcomes such as protection against gastrointestinal tract infections, inflammation, and metabolic diseases. Regular intake of Bifidobacterium in foods is a sustainable way of maintaining the health benefits associated with its use as a probiotic. Owing to their global acceptance, fermented dairy products (particularly yogurt) are considered the ideal probiotic carrier foods. As envisioned in the definition of probiotics as “live organisms,” the therapeutic functionalities of Bifidobacterium spp. depend on maintaining their viability in the foods up to the point of consumption. However, sustaining Bifidobacterium spp. viability during the manufacture and shelf-life of fermented dairy products remains challenging. Hence, this paper discusses the significance of viability as a prerequisite for Bifidobacterium spp. probiotic functionality. The paper focuses on the stress factors that influence Bifidobacterium spp. viability during the manufacture and shelf life of yogurt as an archetypical fermented dairy product that is widely accepted as a delivery vehicle for probiotics. It further expounds the Bifidobacterium spp. physiological and genetic stress response mechanisms as well as the methods for viability retention in yogurt, such as microencapsulation, use of oxygen scavenging lactic acid bacterial strains, and stress-protective agents. The report also explores the topic of viability determination as a critical factor in probiotic quality assurance, wherein, the limitations of culture-based enumeration methods, the challenges of species and strain resolution in the presence of lactic acid bacterial starter and probiotic species are discussed. Finally, new developments and potential applications of next-generation viability determination methods such as flow cytometry, propidium monoazide–quantitative polymerase chain reaction (PMA-qPCR), next-generation sequencing, and single-cell Raman spectroscopy (SCRS) methods are examined.
Billions of people globally live under conditions of water stress and water shortage, or with contaminated water sources. Anthropogenic contaminants pose an extra challenge as water purification technology must be constantly developed or upgraded to deal with newly fabricated pollutants.
One of the UN sustainable development goals is to ensure availability and sustainable management of water and sanitation for all. Therefore, it is vital to develop novel materials and technologies for producing clean drinking water in a human safe, economically reasonable and environmentally sustainable way.
Novel Materials and Water Purification introduces recent approaches to the fabrication of novel material’ for water purification and discusses several significant applications including removal of heavy metals and pharmaceuticals. This is a timely work of high interest to researchers and learners in the fields of water science, water management and materials science.
Besides being known for its natural tourist destinations and beautiful beaches, Lombok Island in Indonesia is also known for its abundant marine and fishery potential, which can be used as development vehicles for the island’s people. However, its richness in marine resources does not contribute significantly to its people’s living standards and economic development. This research aims to investigate the practice of the Blue Economy in a marine wealth region. While many disciplines touch upon the concept of a Blue Economy, little research has examined the ocean-poverty connection in Lombok Island. This article argues that the potential of Lombok’s Blue Economy has not alleviated poverty since the local condition does not support a tendency against romanticizing the notion of Blue Economy as a global developmental platform. The substantial marine potential of the island cannot provide maximum benefit for the people’s welfare due to multiple factors, including financial, human resources, infrastructure, and the government’s goodwill. The significance of this research presents empirical evidence of a missing link in the ocean-poverty nexus. This research examines five drivers of the Blue Economy on the island: pearl, seaweed, fisheries, mangrove, and marine tourism. We maintain a paradox of plenty on the island since the potential from these drivers is immense to address the poverty in Lombok, yet the progress seems idle.
Hydrocolloids are commonly used in food processing to create and modify texture and are irreplaceable in food formulation and texture design. They are primarily starch, non-starch polysaccharides, and gelatin. The functionality of hydrocolloids in texture creation is divided into two main classes: structure formation and structure stabilisation. Texture is generally associated with high molecular weight biopolymers and is perceived through the trigeminal nerve that responds to pressure during mastication. The rheological properties of food soft matter, i.e., its response to forces during mastication and swallowing, generally define its textural characteristics. The chapter focuses on polysaccharides and gelatin and introduces the basic mechanisms of structure formation and texture modulation using hydrocolloids.
Seaweed is rich in many unique bioactive compounds such as polyphenols and sulfated polysaccharides that are not found in terrestrial plant. The discovery of numerous biological activities from seaweed has made seaweed an attractive functional food source with the potential to be exploited for human health benefits. During food processing and digestion, cell wall polysaccharide and polyphenols commonly interact, and this may influence the nutritional properties of food. Interactions between cell wall polysaccharide and polyphenols in plant-based system has been extensively studied. However, similar interactions in seaweed have received little attention despite the vast disparity between the structural and chemical composition of plant and seaweed cell wall. This poses a challenge in extracting seaweed bioactive compounds with intact biological properties. This review aims to summarize the cell wall polysaccharide and polyphenols present in brown, red and green seaweed, and current knowledge on their potential interactions. Moreover, this review gives an overview of the gut modulation effect of seaweed polysaccharide and polyphenol.
Biopolymers are natural polymers derived from renewable sources such as plants, algae, and microbes. As a supportive material for regeneration in dental research, biopolymers are of prime importance. Biopolymers have been widely developed for periodontal, prosthodontics, orthodontic, and endodontic applications in dentistry, including scaffolds, biomembranes such as guided tissue regeneration (GTR), guided bone regeneration (GBR), nanocomposites, hydrogels, barrier membranes, nanofibers, and bioink for 3D printing. Different biopolymers have been traditionally used since time immemorial, such as chitosan, collagen, and hyaluronic acid which are non-versatile, difficult for availability, and not cost-effective in the present scenario. Agar, carrageenan, alginate, fucoidan, and ulvan are biopolymers effectively utilized for dental applications. Seaweed biopolymers are easily available and meet other biopolymers' characteristics for material fabrication. Blending of nanoparticles and antibiotics for slow release with seaweed polymers is possible, like that of other biopolymers. Seaweed biopolymers also support osteogenic processes and cytocompatibility and biocompatibility in nature. Its good resorbable nature and solubility in water with good gel strength favor physical and mechanical properties support for dental applications. Biopolymers derived from seaweeds also exhibit good biocompatibility, biodegradable nature, good structural strength, and induce cell proliferation and differentiation. Seaweed biopolymers exhibit antimicrobial, antioxidant, and anti-inflammatory activities.
Sectors And Flatting Algea In Makam Alkder On Coastal Water Of Syria, which is PART OF MSC LETER: A studay of the Distribution and Biochemical Structure of Benthic Algae in the Northern and Southern Beaches of lattakia.
The sulfate content of carrageenans and agars was obtained from characteristic infrared absorbance bands. The absorbance at 2920 cm-1 attributed to C-H was used as an index for total sugar content. Sulfate was determined from the following absorbance ratios: total sulfate 1250/2920, galactose-4-sulfate, 845/2920, 930/ 2920, and 3,6-anhydrogalactose-2-sulfate, 805/2920. The results indicated that the absorbance at 930 cm-1, attributed to 3,6-anhydrogalactose, was also related to content of galactose-4-sulfate in agars and carrageenans.
Sol–gel and gel–sol phase transitions of κ-carrageenan in various types of salts were studied using photon transmission technique. Here, LiCl, NaCl, KCl, MgCl2, CaCl2, and SrCl2 were chosen as the proper salts for the κ-carrageenan–water system. Photon transmission intensity, Itr was monitored against temperature to determine the sol–gel and gel–sol temperatures (Tsg and Tgs) and activation energies (ΔEsg and ΔEgs). It was observed that Tgs temperatures were notably higher than Tsg due to the hysteresis on the phase transition loops. It was observed that stronger carrageenan gels are formed in the presence of KCl compared to the others. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3008–3016, 2006
A nomenclature system for red algal galactans based on their chemical structures is proposed. The terms 'agaran' and 'carrageenan' are suggested as the generic names for two possible diastereoisometric extreme structures of carbohydrate backbone built of alternating 3-linked beta-D-galactopyranose and 4-linked alpha-galactopyranose residues and differing only in the absolute configuration of the 4-linked alpha-galactose residues (L- or D-, respectively). 'Agarose' and 'carrageenose' are the generic names for the corresponding backbones having 3,6-anhydro-alpha-galactopyranose (also L- and D-) as the 4-linked residue. All the other known regular structures may then be designated as substituted (methylated, sulfated, etc.) derivatives of agaran and agarose (agar group polysaccharides) or carrageenan and carrageenose (carrageenan group polysaccharides). A shortland notation system (uppercase letter code) is also proposed, which is especially useful for designation of hybrid (masked repeating) polysaccharide structures or their corresponding oligosaccharidic fragments and for interpretation of the NMR spectra.
The wide uses of the algal galactans agar, agarose and carrageenans arebased on their unique properties to form strong gels in aqueous solutions. These gels result from peculiar regular chemical structures, specific orderedmolecular conformations and aggregations. In recent years, newmethodologies and instruments have provided a more accurate view of therelationships between the chemical structure and the gelling characteristicsof these complex hybrid and heterogeneous polysaccharides. Methanolysisand reductive acid hydrolysis procedures coupled to differentchromatographic separations allowing the quantitative determination of allthe constituent sugars including the acid labile 3,6-anhydyrogalactose areparticularly emphasised. Means of determining sugar linkages, substitutionsand sequences using chemical, enzymatic and spectroscopic methods arealso presented. Developments in multi- and low-angle laser-light diffusiondetectors coupled to high performance size exclusion chromatography nowrender the determination of molecular weight and molecular weightdistribution of these galactans more accessible. Such techniques also yieldnew information on the aggregate formation of these sulphatedpolysaccharides. These and other data question the existence of thegenerally assumed intertwined double helical conformations of thesegalactans during gel formation.
Advances in the chemistry and physico-chemical properties of agar since the review of Araki at the Fifth International Seaweed Symposium in 1965 are discussed. These advances are essentially the result of better separation techniques of the heterogeneous family of polysaccharides known as agar, the use of nuclear magnetic resonance spectroscopy, the use of agarases and, particularly, the use of combinations of the three approaches. Although physico-chemical methods have evolved, particularly molecular-weight determinations, X-ray diffraction data and molecular modelling of agar, correlations between chemical and functional properties of agar and agarose and their gelation mechanisms remain to be studied.
The Food and Agriculture Organization of the United Nations (FAO) is an autonomous agency within the United Nations system. The organization had a membership of 180 countries in 2001.
A series of propylene glycol alginates (PGA) with degrees of esterification (D.E.) in the range of 32-93 % were investigated with respect to surface activity and gelling potential. The surface tension measurements revealed increasing surface activity with increasing contents of propylene glycol groups. The rheological characterization of the PGA series calcium gels uncovered that the gelling potential of the PGAs was surprisingly well conserved even at intermediate degrees of esterification, assumed to reflect heterogeneity in the esterification pattern. For the PGAs of highest degree of esterification the assumed electrostatic point associations combined with hydrogen bonding lead to the rapid formation of weak gels. The rheological properties of high D.E. PGA solutions could be easily modified through the addition of sodium chloride and urea. Self-supporting, heterogeneous and stable PGA and PGA/unmodified alginate gelled foams were prepared applying the internal setting method and characterized with respect to mechanical properties and density. Increasing foamability and corresponding decrease in densities of the gelled foams and their mechanical strength was observed with increasing D.E..
Mixtures of alginate and high methoxy pectins formed thermoreversible gels below pH 3.8 without any addition of sugar, provided that D-glucono-deltalactone (GDL) was used as a slow acidifier in the cold. The gelling occurred at conditions where neither alginate nor the high methoxy pectin gelled alone. The strength and melting points of these synergistic gels increase with decreasing pH and increasing content of L-guluronic acid residues in the alginates. The gelling effect was correlated to the sequential distribution of the two monomers, D-mannuronic (M) and L-guluronic acid (G) residues, in the alginate chain. The results indicated that "blocks" of at least four contiguous G-units were necessary for gelling to occur. The results were discussed in view of existing molecular theories for synergistic gelation.
Agar has its origins in Japan in 1658. It was introduced first in the Far East and later in the rest of agarophyte seaweed producing countries. Its use was introduced in Europe in 1859 and it was being used in bacteriological culture media in 1882. This chapter discusses the seaweeds used the world over as raw material for agar production (agarophyte seaweeds), and presents the industrial processes used for agar production. The chemical structure of agar and its fractions, such as agaroses and agaropectines, are presented, and the relation between its chemical structures and properties are also shown. The gelation and melting of agar and its fractions, such as agaroses and agaropectines, is based only in the formation of hydrogen bridges (physical gels), and thus gelation is extraordinarily reversible. The synergies and antagonisms among agar and other products in the gelation processes are studied. Various applications of agar are presented, in some of which agar is irreplaceable. Use formulations are shown in food preparations. Diverse applications are also presented, in the preparation of food for insects, for plant tissue culture, and in the preparation of culture media for microorganisms, as well as gels for denture moulding, the reproduction of archaeological remains or of fingerprinting in police work. Agar gels are important in food preparations with high content in soluble gross fibre, as agar is the food additive with the highest content in said fibre, superior to that of 94%. Lately the production of more easily soluble agars in water at temperatures below boiling point has been initiated, which proves to have noteworthy advantages for some of its applications. A comparative study is presented among the commercial products existing in the world market.
Red seaweeds contain naturally-occurring polysaccharides which fill the voids within the cellulose structure of the plant. This family of polysaccharides include carrageenan and furcellaran. Gels are produced by heating and cooling solutions of these polysaccharides to give soft, elastic gels with iota carrageenan and firm, brittle gels with kappa carrageenan and furcellaran. Lambda carrageenan gives viscous solutions. Carrageenan is utilised for water dessert gels and glazes, flans, canned meats and pet food. In addition, carrageenan interacts with protein to stabilise, thicken and gel a wide range of products including milk drinks and shakes, ice cream and dairy desserts.
Propylene glycol alginates give greater increases in foam stability than are given by equal amounts of neutral polysaccharides. This is due to electrostatic interaction between carboxyl groups on the glycol alginate molecules and amino groups on the peptides in the bubble wall. This interaction within the bubble wall is responsible for the stabilizing action of propylene glycol alginate against the harmful effects of lipid-like materials in beer foam.
The combination of different gelling and non-gelling hydrocolloids is known to yield complex systems with a wide range of mechanical properties. Here, the influence of the non-gelling hydrocolloids sodium-alginate and xanthan on the gelation of agarose is investigated. The two polyelectrolytes differ significantly in their flexibility, leading to opposing effects on the thermo-mechanical properties of the resulting composite gels. The network structure of the agarose as well as viscoelasticity, gelling temperature and thermal stability of the gels are altered. These properties are investigated by strain and temperature dependent oscillatory rheological measurements as well as confocal laser scanning microscopy. A phenomenological model to describe the network formation of agarose in the presence of alginate or xanthan respectively is presented.
This work analyses the release of n-hexanal and d-limonene from edible films, previously encapsulated in the iota-carrageenan matrix (with and without lipid). Both volatile compounds have different physico-chemical properties. The effect of temperature (25 °C and 37 °C) and dissolution medium (water and 0.9% NaCl) on the release and retention of aroma compounds were studied. Hydrophobicity and wettability properties of active iota-carrageenan films were also studied and they were related with the internal and surface microstructure of films. Results highlight that d-limonene is encapsulated in the lipid phase of the films decreasing the release in the salt medium. d-limonene, the most hydrophobic, was more sensitive to the temperature changes than hexanal. Thus, this work gives an idea of the release of aroma compounds encapsulated in iota-carrageenan films in aqueous media.
The binding of the binary polyuronide alginic acid to alkaline earth (Mg2+, Ca2+, Sr2+, Ba2+) and lanthanide (La3+, Pr3+, Nd3+, Eu3+, Tb3+) ions was studied by 13C NMR spectroscopy. Divalent metal ions showed a preference for GG blocks and an increase in the extent of binding with increasing ionic radius. Molecular modeling studies of calcium–alginate dimers support the assertion that this preference results from the secondary structure of alginic acid. Trivalent metal ions studied showed a preference for GG blocks and an increase in the extent of binding for both GG and MM blocks with increasing charge density. The contrast in the mode of interaction of the alkaline earth and lanthanide metal ions with alginic acid can be associated with differences in coordination number and/or waters of hydration remaining in the inner sphere of the lanthanide ions.
Agars have been isolated from the nine currently recognised species of red seaweed in the genus Curdiea. Characterisation of their structures by chemical and spectroscopic methods showed all had a basic repeating structure of alternating 3-linked β-d-galactopyranosyl and 4-linked 3,6-anhydro-α-l-galactopyranosyl units but substituted with high levels of methyl ether groups. The native agars, isolated with hot aqueous buffer solution, had only weak gelling abilities owing to some of the 4-linked units being present as precursor α-l-galactopyranosyl-6-sulfate units. Conversion of these precursor units to the corresponding 3,6-anhydrides by treatment with hot alkali generally led to increased gel strength. Agars from Curdiea angustata, C. codioides, C. crassa and C. flabellata were predominantly methylated on position 6 of the 3-linked β-d-galactopyranosyl units, while agars from C. irwinii, C. sp. nov. (Three Kings), and C. racovitzae were almost completely methylated on position 2 of the 4-linked 3,6-anhydro-α-l-galactopyranosyl units. The agars from C. coriacea and C. obesa, however, were nearly completely methylated at both these positions. The alkali-modified agars from these latter two algae had gel-melting temperatures significantly above the boiling point of water. Small amounts of unusual 4-O-methylxylopyranosyl branching units were detected in the agars from C. irwinii and C. obesa.
High-resolution, 13C-n.m.r. spectra of slightly depolymerised alginates have been interpreted. The sequence of monomer units, l-guluronate (G) and d-mannuronate (M), markedly influenced the chemical shifts. At 50 MHz, some of the individual carbon resonances of both units were resolved into four lines, in evident dependence upon the identities of the units immediately preceding and following them in the chains. The relative intensifies of the signals permitted rapid computation of (1) monomeric composition (M/G ratio), (2) monomeric sequence in terms of a complete set of four diad and eight triad frequencies, and (3) the composition (M/G ratio) of end units and of the units adjacent to M-residues at the non-reducing end. The diad frequencies indicated that alginate was a block co-polymer containing number-average, co-monomer block-lengths of ∼2−8. The triad frequencies indicated average lengths of ∼4−8 for blocks containing two or more units, these being somewhat longer for G- than for M-blocks. Regions of the chains having a strictly alternating sequence of M- and G-residues were short. The relative occurrence of G-centred triads deviated significantly from those predicted by first-order Markovian statistics.
From light-scattering and viscosity experiments, it was found that the relative extension of the three types of “blocks” in alginate increased in the order “MG-blocks” <“MM-blocks”<“GG-blocks”, both in 0.1M aqueous sodium chloride and in the unperturbed state. From a comparison with calculated free-rotation dimensions, it was concluded that this was due to a difference in the hindrance to rotation around the glycosidic linkage in the different blocks. Calculations by statistical mechanics, using Kitaygorodsky potential functions for the non-bonded interaction between atomic groups in adjacent dimers, yielded unperturbed dimensions which were in agreement with the above order, only when the L-guluronic acid residue was assumed to adopt the 1C (1C4) conformation.
Carrageenans represent one of the major texturising ingredients in the food industry. They are natural ingredients, which are used for decades in food applications. Carrageenan is a generic name for a family of linear, sulfated galactans, obtained by extraction from certain species of red seaweeds (Rhodophyta). Since natural carrageenans are mixtures of different sulfated polysaccharides, their composition differs from batch to batch. Therefore, the quantitative analysis of carrageenan batches is of greatest importance for both ingredient suppliers and food industries to deliver a constant consumer product and to develop new applications based on their unique intrinsic properties. Nowadays NMR spectroscopy is one of the standard tools for the determination of the chemical structure of carrageenan samples. This review gives an overview of NMR-spectroscopy (both 1H- and 13C-NMR) as a powerful tool for the qualitative and quantitative analysis of carrageenan samples. In addition to tables containing chemical shift data for both 1H- and 13C-spectra, details about sample preparation, selective degradation and fractionation techniques are included.
This chapter discusses the interaction of galactomannans with other polysaccharides. The general chemistry of the galactomannans has been reviewed by Whistler and Smart and others. The chapter discusses the uses of guar and locust-bean gums in various industrial applications and investigates the structural chemistry of galactomannans, especially as revealed by enzymic studies. Mixtures of locust-bean gum with the non-gelling polysaccharide from Xanthomonas campestris have been shown to interact synergistically to give firm, rubbery gels, whereas the use of the galactomannan from C yamopsis tetragonolobus (guar gum) results only in viscosity enhancement. These interactions are important in many of the industrial applications of galactomannans, and a study of them may also help provide an understanding of the associations among polysaccharide chains, contributing to biological cohesion and texture. The two main groups of galactomannan polysaccharides are those derived from (1) the endosperm of plant seeds, the vast majority of which originate in the Leguminoseae, and (2) microbial sources, in particular, the yeasts and other fungi. D-Mannose and D galactose are also found in numerous other plant polysaccharides—for example, glucomannansm, mannans, and galactans.
Microencapsulation involves the incorporation of food ingredients, enzymes, cells, or other materials in small capsules. Microcapsules offer food processors a means with which to protect sensitive food components, ensure against nutritional loss, utilize otherwise sensitive ingredients, incorporate unusual or time-release mechanisms into the formulation, mask or preserve flavors and aromas, and transform liquids into easily handled solid ingredients. Various techniques are employed to form microcapsules, including spray drying, spray chilling or spray cooling, extrusion coating, fluidized-bed coating, liposome entrapment, coacervation, inclusion complexation, centrifugal extrusion, and rotational suspension separation. Recent developments in each of these techniques are discussed in this review. Controlled release of food ingredients at the right place and the right time is a key functionality that can be provided by microencapsulation. A timely and targeted release improves the effectiveness of food additives, broadens the application range of food ingredients, and ensures optimal dosage, thereby improving the cost effectiveness for the food manufacturer. Reactive, sensitive, or volatile additives (vitamins, cultures, flavors, etc.) can be turned into stable ingredients through microencapsulation. With carefully fine-tuned controlled-release properties, microencapsulation is no longer just an added-value technique, but the source of totally new ingredients with matchless properties.
The stoichiometry of calcium-ion chelation to alginate chains has been investigated by circular dichroism (c.d.), and by equilibrium dialysis in the presence of various concentrations of sodium chloride. C.d. intensity in the carboxylate π → π * spectral region increases linearly with calcium-ion concentration up to a level equivalent to half the total poly-L-guluronate stoichiometric requirement, and thereafter shows little further change. Similarly, the level of bound calcium resistant to displacement by swamping concentrations of sodium ions is equivalent to half the stoichiometric requirement of poly-L-guluronate chain-sequences alone. In terms of the previously developed “egg-box” model of co-operative junction-zone formation in alginate gelation, these results are interpreted as showing that the primary mechanism of interchain association is by dimerisation of poly-L-guluronate chain-segments in a regular, buckled, two-fold conformation related to that characterized for the free acid in the solid state, with tight interchain chelation of calcium to the carboxylate groups on the interior faces of the dimer (i.e., half the carboxylate residues of the participating chain-sequences). This interpretation is entirely consistent with previous evidence from electron microscopy, and offers a simple rationalisation of experimental results from competitive-ion binding studies.
The gelling temperature of 1.5% agarose sols was found to increase with increasing methoxyl content of the agarose. Of about 50 preparations tested, only 3 failed to follow this pattern. High methoxyl-type agaroses could be fractionated into portions of higher and lower methoxyl content having correspondingly higher and lower gelling temperatures.
The effect of a novel alginate/nano-Ag coating material on the preservation quality of shiitake mushroom (Lentinus edodes) during 4±1°C storage was investigated. The results showed that the alginate/nano-Ag coating had quite a beneficial effect on the physicochemical and sensory quality, compared to the control treatment. After a 16-day storage, mushroom weight loss, softening, and browning of the alginate/nano-Ag coating were significantly inhibited. The lower microbial counts, including mesophilic, psychrophilic, pseudomonad, and yeasts and moulds, in treated mushrooms during storage should be attributed to the alginate/nano-Ag coating. Meanwhile, the contents of the reducing sugar, total sugar, total soluble solids and electrolyte leakage rate were increased to 3.9mg/g, 11.2mg/g, 5.1% and 16.5% for the alginate/nano-Ag coating and 3.7mg/g, 8.3mg/g, 6.3% and 31.7% for the control treatment. Therefore, the alginate/nano-Ag coating could be applied for preservation of the shiitake mushroom to expand its shelf life and improve its preservation quality.
The sequence and composition of uronate residues in intact alginate samples have been obtained by high-resolution 1H-n.m.r. spectroscopy. The viscosity problem was overcome by a slight, controlled depolymerization of the alginate samples before the 1H-n.m.r. spectra were recorded at 90°. The mannuronate (M)/guluronate (G) molar ratio was obtained from the intensities of the signals for the anomeric protons. A sequence-dependent deshielding of H-5 of the guluronate residues made it possible to determine the fractions of the four possible doublets of nearest neighbours along the chain. The results were wholly consistent with 13C-n.m.r. data. Significant deviation from comparable results obtained by chemical analysis appeared only for samples containing a large fraction of the mixed doublets.
Studies were carried out on the instrumental textural evaluation of restructured carrot cubes. The experiment was conducted by incorporating different levels of alginate, glucono delta lactone (GDL), and calcium salt to the carrot pulp. Investigations showed that as pulp level increased from 0 to 90%, there was a corresponding decrease in failure stress, failure strain, and deformability modulus. Instrumental textural profile analysis (TPA) parameters viz. hardness, springiness, gumminess, cohesiveness, chewiness, and resilience also showed a similar trend. Effect of formulation variables, i.e., alginate, GDL, and calcium salt on hardness (response variable) were evaluated by the application of response surface methodology. All the three ingredients showed a significant (P < 0.05) influence on hardness of carrot gel. Heat treatment of restructured carrot samples resulted in an increased hardness, cohesiveness, gumminess, and chewiness while springiness, cohesiveness, and resilience decreased. The data indicated that the shrinkage during thermal treatment may be responsible for the change in textural attributes. The authors concluded that a thermally stable restructured product with appreciable textural integrity can be obtained from carrot pulp.
Fractionation of Difco Bacto agar on DEAE Sephadex (Clt-) has shown that the concept that agar is made up of two polysaccharides, neutral agarose and charged agaropectin, is an over-simplification. The results indicate that
Differential scanning calorimetry (DSC) and electron spin resonance spectroscopy (ESR) have been used to probe the mechanism of gelation in gels formed by mixtures of konjac mannan and kappa-carrageenan and have indicated that an association occurs between konjac mannan chains and (aggregated) kappa-carrageenan helices. On cooling mixed systems at low ionic strength, a coil-helix transition of kappa-carrageenan, as evidenced by a DSC exothermic peak (peak I), occurs at a temperature significantly higher than the ''normal' transition temperature observed for kappa-carrageenan alone. This transition is accompanied by a partial immobilization of the konjac mannan chains, as evidenced by ESR spectroscopy. When kappa-carrageenan is in excess, a second transition (peak II) appears at the normal transition temperature. Both transitions are ion specific, and they shift in the same way with added salt, which strongly suggests that they both reflect the formation of normal kappa-carrageenan helices. At sufficiently high ionic strength, only one transition is apparent in the DSC curve, and its effect on the mobility of the konjac mannan chains is considerably reduced. Both the peak I and peak II transitions show a marked thermal hysteresis, as evidenced by DSC heating experiments, which demonstrate that both transitions are accompanied by aggregation processes subsequent to the coil-helix transition. The transition enthalpy per mole of carrageenan is significantly less in the mixtures than for kappa-carrageenan alone, indicating that the kappa-carrageenan self-aggregation is affected by the presence of konjac mannan. The results are interpreted in terms of the formation of mixed aggregates of kappa-carrageenan helices and konjac mannan, possibly involving bundles of self-aggregated kappa-carrageenan helices covered with surface-adsorbed konjac mannan chains.
The effect of sucrose, glucose, urea, and guanidine hydrochloride on dynamic viscoelasticity and differential scanning calorimetry (DSC) curves of κ-carrageenan gels were studied. The dynamic Young's modulus E′ and the melting point of κ-carrageenan gels increased with increasing sugar content. Urea weakened the gelling ability. Guanidine hydrochloride strengthened the gelling ability up to a certain amount, but excessive addition of guanidine hydrochloride weakened the gelling ability. The heat absorbed on forming 1 mol of junction zones showed a maximum as a function of added content of sugars or guanidine hydrochloride. It is suggested that sugars may create junction zones and stabilize the structure of junction zones, but the excessive addition of sugars immobilizes free water necessary for junction zone formation. Low concentrations of guanidine hydrochloride shield the electrostatic repulsions between sulfate groups in κ-carrageenan molecules and stabilize the structure of junction zones. However, higher concentrations of guanidine hydrochloride disrupt hydrogen bonds and weaken the gel-forming ability.
The effect of sucrose, glucose, guanidine hydrochloride, or urea on the dynamic elastic modulus E′ and mechanical loss tangent and on the differential scanning calorimetry (DSC) curves of agarose gels were examined. E′ increased with increasing concentration of sugars up to a certain amount, but the excessive addition of sugars decreased E′. The DSC endothermic peak accompanying the transition from gel to sol shifted to higher temperatures, while the heat absorbed on forming 1 mol of junction zones increased and then decreased with increasing sugar concentration. Guanidine hydrochloride or urea decreased E′ and shifted the gel to sol transition temperature to lower temperatures. The mechanism by which these chemical reagents weaken or strengthen the gel-forming ability was discussed.
The sol → gel → sol transformation of aqueous K-carrageenan occurs with complex changes in optical rotation which may be explained qualitatively in terms of the double helix model for junction zones. Evidence is given that the double helices in the gel are normally aggregated but can be kept separate within a narrow temperature range, and that gelation is a kinetic rather than an equilibrium process. An attempt has been made to predict the preferred conformations of irregular carrageenans by joining segments of simpler polysaccharides; the effect of certain structural variations on gel properties may then be explained. Model building in the computer does not exclude the possibility of double helices for the following polysaccharides which are structurally related to K- and i-carrageenan: hyaluronic acid, chondroitin, chondroitin 4-sulfate, chondroitin 6-sulfate, dermatan sulfate, keratan sulfate, agarose, porphyran, μ-carrageenan and furcellaran.
Sodium alginate fractions derived from three different sources—Laminaria hyperboria (75% guluronate), Fucus vesicularus (95% mannuronate), and Azotobacter vinelandii (85% mannuronate)—were investigated in aqueous solution over a wide range of ionic strength and pH using the techniques of light scattering, viscometry, and osmometry. Light-scattering data extrapolated to infinite ionic strength yielded b0 = 4.7 ± 0.3 and 3.0 ± 0.2 nm for the unperturbed effective bond lengths of the guluronate- and mannuronate-rich samples, respectively. These values are in the same ratio as predicted by conformational analysis, although lower by a factor of 0.7, probably due, in part at least, to the fact that measurements cannot be made on pure homopolymers. A comparison of the light-scattering and the viscosity data indicated that Φ in the Flory-Fox equation is lower than for more flexible polymers and increases with molecular weight, probably due to decreasing hydrodynamic permeability. Mark-Houwink exponents obtained from data extrapolated to infinite ionic strength were found to be considerably greater than 0.5, and we attribute this entirely to a variation in Φ. Comparison of the results obtained for the two mannuronate-rich samples indicated that the value of Φ and its variation with molecular weight can, in the case of alginates, differ markedly for chains, which, although having chemical differences, have similar chain statistics.
13C-NMR spectroscopic studies have been made on alginate solutions undergoing sol–gel transition induced by four different divalent cations: Ca, Cu, Co, and Mn. From the analysis of nmr spectra and relaxation times, we have found different interaction modes existing between the Ca–alginate systems and the transition metal (Cu, Co, and Mn)–alginate systems. In the Ca–alginate systems, there exists a specific interaction characterized by a strong autocooperative binding between guluronate residues and calcium ions, and all functional groups in guluronate residues are considered to involve the interaction with calcium ions. On the other hand, in transition metal (Cu, Co, and Mn)–alginate systems, sol–gel transition is characterized by a complex formation in which the carboxyl groups in both mannuronate and guluronate residues are coordinated to metal ions. The other functional groups, like hydroxyl groups, do not participate in the binding to metal ions. It is suggested by relaxation time measurements that from a microscopic point of view the sol–gel transition phenomena can be explained as a dynamic process in which the low frequency molecular motions are dominant and increase their proportions with the formation of three-dimensional cross-links. © 1993 John Wiley & Sons, Inc.
The synergistic interaction between alginate and pectin was systematically investigated using samples of different chemical compositions. Pectin samples with high and low degrees of esterification (DE) and amidated pectin (LA) were mixed with alginate of high and low M/G (mannuronic acid/guluronic acid) ratio. The microstructure of the gels was characterised by TEM (transmission electron microscopy) and the rheological properties by dynamic oscillatory measurements. The TEM images of the mixed gels revealed a coarse, strand-like network with pores in the range of microns, independent of the ratio and the composition of the samples. A comparison with the microstructure of a pure pectin gel showed that the pectin network was composed of thinner strands and smaller pore sizes than the mixed network.The strongest synergism was found between alginate with low M/G ratio and pectin with a high DE. These gels show the highest G′ (storage modulus) and the fastest kinetics of gel formation. Lower G′ and slower kinetics were found for gels based on alginate with a high M/G ratio and pectin with a low DE, or LA pectin. The nature of the pectin sample affected the network density and the strand characteristics. In contrast, no influence was found of the alginate sample. Gels based on pectin with a high DE showed a dense network composed of highly branched strands, whereas the LA-pectin based gels showed a sparse, open network, composed of long, straight strands. A relation close to 1:1 for low-G alginate and pectin with a high DE resulted in gels with the highest G′. In contrast, for LA-pectin based gels, the highest G′ was found for mixtures of alginate dominant ratios. For the overall network properties, the homogeneity in the microstructure decreased with alginate content, independent of the pectin sample.
The objectives of this study were to assess the effect of the addition of different hydrocolloids on gluten-free batter properties and bread quality and to obtain information about the relationship between dough consistency and bread quality. Breads were made of rice, corn and soy flours and 158% water. Following hydrocolloids were added: carrageenan (C), alginate (Al), xanthan gum (XG), carboxymethylcellulose (CMC) and gelatine (Gel). Batter consistency, bread specific volume (SV), crumb analysis, crust colour, crumb hardness and staling rate were determined. Hydrocolloids increased batter consistencies: the highest value was obtained with XG, which doubled that of control batter, followed by CMC. Breads with hydrocolloid presented higher SV than control, especially with XG whose SV was 18.3% higher than that of control bread. A positive correlation was found between SV and batter consistency (r = 0.94; P < 0.05). Crumbs with Gel, XG and CMC presented higher cell average size. XG and CMC crumbs looked spongier. Breads containing hydrocolloid evidenced lighter crusts. Crumb firmness was decreased by XG and CMC addition, and staling rate was slower. Overall, XG was the hydrocolloid that most improved gluten-free bread quality. These results show that, in formulations with high water content, batter consistency is strongly associated with bread volume.
Superpositioning principles were applied twice to model temperature (25 to 125 °C) and concentration (0.005 to 0.040% w/w) effects on skim milk and carrageenan solutions. Samples were analyzed using a controlled stress rheometer equipped with a pressurized sealed cell, permitting measurements well above standard boiling conditions. Individual samples were sheared between 10 and 160 s−1, and predictive equations were developed to predict Newtonian viscosity as a function of temperature and carrageenan concentration. The superpositioning technique coupled with advancements in rheological instrumentation permits high temperature measurements and offers a strategy for viscosity determination for thermal processing unit operations.
The administration of probiotic bacteria as nutraceuticals is an area that has rapidly expanded in recent years, with a global market worth $32.6 billion predicted by 2014. Many of the health promoting claims attributed to these bacteria are dependent on the cells being both viable and sufficiently numerous in the intestinal tract. The oral administration of most bacteria results in a large loss of viability associated with passage through the stomach, which is attributed to the high acid and bile salt concentrations present. This loss of viability effectively lowers the efficacy of the administered supplement. The formulation of these probiotics into microcapsules is an emerging method to reduce cell death during GI passage, as well as an opportunity to control release of these cells across the intestinal tract. The majority of this technology is based on the immobilization of bacteria into a polymer matrix, which retains its structure in the stomach before degrading and dissolving in the intestine, unlike the diffusion based unloading of most controlled release devices for small molecules. This review shall provide an overview of progress in this field as well as draw attention to areas where studies have fallen short. This will be followed by a discussion of emerging trends in the field, highlighting key areas in which further research is necessary.
Food quality preservation requires that the initial properties of the food products be maintained by protecting them from the environment and by limiting the gain or loss of external matter. Barrier edible films can preserve food quality by controlling moisture transfer, oxygen uptake or the loss of volatile aroma compounds. Edible films made of iota-carrageenans display interesting advantages: good mechanical properties, stabilization of emulsions and reduction in oxygen transfer. Moreover, lipid globules incorporated as emulsion-based films can be the carriers for the encapsulation of active volatile molecules such as flavor compounds. Such films also enhance the barrier properties. The aim of this study was to develop a better understanding of the influence of microstructure, composition, surface properties and the interactions between film components on aroma barrier properties. The study of the aroma compound permeability of films with or without encapsulated aroma compound and/or fat, showed that interactions between aroma compound/iota-carrageenan and aroma compound/fat modifies the structure on both sides (surfaces) of the film, and therefore, its permeability. This study presents new understanding of the role of emulsion-based edible films as a matrix able to protect encapsulated aroma compounds and its aroma barrier properties.