Studies of melatonin photoreactivity in water solutions: An effect of an external heavy atom I − on UV/Vis absorption, fluorescence and phosphorescence spectra is explored. The data allowed determination of relevant energetics for the system.The heavy atom effect (HAE) of I − on melatonin is clearly found to induce an intersystem crossing from the lowest energy singlet state to the lowest energy triplet state ( T 1 ) by a state mixing. Lifetime for the first excited triplet states of melatonin in association with I − and quenching rates for halomethanes (CH 2 X 2 , CHX 3 , CY 4 , X = Cl, Br, Y = Cl) are determined from Time-Correlated Single-Photon Counting decay curves for the phosphorescence. Dramatic alterations in quenching rate constants with quenchers as CH 2 X 2 < CHX 3 < CX 4 and Cl < Br are attributed to energy transfer from an I −… M e* ( T 1 ) complex to low-lying electronic states of the halomethanes followed by dissociation to form R and X fragments. Relevance of the melatonin photoreactivity to photosensitizer properties in organic media is discussed. Graphical abstract

A growing concern for overall health is driving a global market of natural ingredients not only in the food industry but also in the cosmetic field. In this study, a screening on potential cosmetic applications of aqueous extracts from three Icelandic seaweeds produced by pulsed electric fields (PEF) was performed. Produced extracts by PEF from Ulva lactuca, Alaria esculenta and Palmaria palmata were compared with the traditional hot water extraction in terms of polyphenol, flavonoid and carbohydrate content. Moreover, antioxidant properties and enzymatic inhibitory activities were evaluated by using in vitro assays. PEF exhibited similar results to the traditional method, showing several advantages such as its non-thermal nature and shorter extraction time. Amongst the three Icelandic species, Alaria esculenta showed the highest content of phenolic (mean value 8869.7 µg GAE/g dw) and flavonoid (mean value 12,098.7 µg QE/g dw) compounds, also exhibiting the highest antioxidant capacities. Moreover, Alaria esculenta extracts exhibited excellent anti-enzymatic activities (76.9, 72.8, 93.0 and 100% for collagenase, elastase, tyrosinase and hyaluronidase, respectively) for their use in skin whitening and anti-aging products. Thus, our preliminary study suggests that Icelandic Alaria esculenta-based extracts produced by PEF could be used as potential ingredients for natural cosmetic and cosmeceutical formulations.

Background: Sugar kelp (Saccharina latissima, formerly known as Laminaria saccharina) is a brown seaweed which naturally occurs in the North Atlantic. Seaweeds may be one of the last natural food resources abundantly available. They are known to contain many compounds which may have additional functional benefits. This edible seaweed is characterized by high content of nutrients including carbohydrates and polyphenols, which are recognized antioxidants. Because their natural environment is a 3% saline solution, they are very resistant to mild extraction methods. However, extracts from solvent extractions usually contain residual solvents, making them unacceptable for high quality functional foods and high end cosmetics. The objective of this study was to test the biological properties of three extracts from sugar kelp (Saccharina latissima).Methods: Cold water, hot water, and ethanol: water (70:30 v/v) extracts were prepared. Total Carbohydrate Content (TCC) was determined by the phenol – sulphuric acid method and values were expressed as mg of fucose/g of dry extract. Total Polyphenol Content (TPC) was determined and expressed as mg of Gallic Acid Equivalent (GAE)/100g of dry extract. Oxygen Radical Absorbance Capacity (ORAC) assay was performed for all extracts and values were expressed as µM of Trolox® Equivalent/g of dry extract. Human leukemia monocytic cell line (THP-1) was used to investigate the bioactivity of Saccharina extracts. Extracts were applied to PMA differentiated THP-1 cells. Cytotoxicity of derived extracts was assessed by light microscopy followed by XTT proliferation assay. Enzyme-linked Immunosorbent assays (ELISA) were performed to determine secretion of interleukin – 10 (IL-10), tumor necrosis factor – α (TNF-α) and interleukin – 6 (IL-6).Results: The cold water extract exhibited very toxic properties toward macrophages and was thereby excluded from the experimental proceedings with use of the macrophages. Among all the tested extracts, the hot water extract was richest in sugars (682±243 mg fucose/g dry extract) and polyphenols (96.5±5.6 mg GAE/g dry extract), which was correlated to the determined ORAC values (1686±99 μM TE/g dry extract). The addition of hot water and ethanol extracts at concentrations 100 μg/ml triggered secretion of pro-inflammatory cytokine TNF-α suggesting immunomodulatory properties of Saccharina extracts toward macrophages. Conclusions: The present study suggests that carbohydrate enriched extracts from Icelandic edible seaweed Saccharina latissima have antioxidant and immunomodulatory properties towards human THP–1 derived macrophages. The carbohydrate and polyphenol correlated with ORAC values confirming antioxidant properties of the derived extracts. The hot water extract affected the pro–inflammatory (TNF–α) and anti–inflammatory (IL–10) cytokine secretion in macrophages, suggesting their bioactivity through immunomodulatory actions and can be considered for practical applications in functional foods and cosmetics.Keywords: Seaweeds; Saccharina latissima; bioactivity; antioxidants; immunomodulation

Background: Seaweeds represent one of the few remaining food sources available globally which are not being fully utilized or even over utilized. Kelps (Laminaria spp.) are one of the numerous species of brown seaweeds, a popular marine vegetable, which has been used as a source of iodine and minerals for centuries. Kelps contain anionic polysaccharides called fucoidans heteroglycans with L – fucose units. Their monosaccharide composition, physicochemical and bioactive properties vary between seaweed species. The objective of this work was to evaluate the bioactive properties of laminaria fucoidan (L. digitata and L. hyperborea) toward THP–1 macrophages, a human macrophage like cell line, and investigate its potential antioxidant and immunomodulatory characteristics.Methods: THP-1 macrophages were incubated with five fucoidan concentrations. The Oxygen Radical Absorbance Capacity (ORAC) assay was determined for cell lysates and for the fucoidan extract, in addition to Total Polyphenol Content (TPC). Cytotoxicity of fucoidan was assessed by light microscopy, followed by XTT proliferation assay. Enzyme–linked immunosorbant assays (ELISA) were performed to determine concentrations of the secreted tumor necrosis factor α (TNF-α), interleukin 6 (IL–6), and interleukin 10 (IL–10). Results: Fucoidan did not affect macrophage ability to scavenge oxygen radicals (ORAC) confirming its antioxidant properties toward activated macrophages. The laminaria fucoidan extract at 100 µg/ml concentration lowered macrophage viability. Lower concentrations of laminaria fucoidan did not have impact on cell viability. Very low concentration of fucoidan at 0.1 µg/ml triggered secretion of TNF-α. However, IL–6 and interleukin IL–10 were expressed when concentration of applied fucoidan was 10 µg/ml indicating bioactivity of laminaria fucoidan through immunomodulatory actions.Conclusions: The study demonstrated how laminaria fucoidan may have bioactive properties towards THP–1 macrophages. Changes in cytokine secretion between pro–inflammatory (TNF–α, and IL–6) and anti–inflammatory (IL–10) cytokines confirmed bioactivity of the laminaria fucoidan extracts.Keywords: Seaweeds, Kelps, Laminaria, fucoidan, bioactivity, macrophages

Atlantic sea cucumber (Cucumaria frondosa) is a marine invertebrate that occurs naturally in the North Atlantic. Its collagen rich body walls make the sea cucumber an appreciated food source in many countries. The heteroglycans derived from the cartilage of Atlantic sea cucumbers have shown potential as a source of bioactive compounds, but further investigation is needed to confirm this hypothesis. The objectives of this work were to test the immunomodulating properties of heteroglycan fractions (FCFs) derived from Atlantic sea cucumbers toward phorbol 12-myristate 13-acetate (PMA) differentiated THP-1 macrophages. Oxygen Radical Absorbance Capacity (ORAC) was determined and cell culture media was collected and analyzed for presence of pro-inflammatory and anti-inflammatory cytokines (TNF-α, IL-6, and IL-10). FCFs toxicity toward macrophages was evaluated by light microscopy and confirmed by XTT proliferation assay. Heteroglycans derived from cartilage of Atlantic sea cucumber showed immunomodulatory activity in THP-1 macrophages. FCF-1, −2, and − 3) at concentrations 0.1–100µg/mL induced levels of TNF-α, IL-6, and IL-10 proofing their bioactivity towards THP-1 macrophages. However, fractions of FCF-1 and FCF-2 may have induced oxidative stress in the macrophages, which possibly could lead to decreased cellular viability.

Hypothesis: This study demonstrates that tuning the shell thickness of lipid particles can modulate their oxidative stability. We hypothesized that a thick crystallized shell around the incorporated fish oil would improve the oxidative stability due to the reduced diffusion of prooxidants and oxygen.Experiments: We prepared solid lipid nanoparticles (5% w/w lipid phase, 1.5% w/w surfactant, pH 7) by using different ratios of tristearin as carrier lipid and omega-3 fish oil as incorporated liquid lipid stabilized by high- or low-melting lecithin. The physical, polymorphic and oxidative stability of the lipid particles was assessed.Findings: The high-melting lecithin was the key in inducing the formation of a solidified tristearin shell around the lipid particles by interfacial heterogeneous nucleation. Lipid particles containing a higher ratio of tristearin showed a better oxidative stability. The results revealed that a crystallized tristearin layer above 10 nm was required to inhibit oxidation of the incorporated fish oil. This cut-off was shown for lipid particles containing 50-60% fish oil. This research gives important insights into understanding the relation between the thickness of the crystallized shell around the lipid particles and their chemical stability. (C) 2016 Elsevier Inc. All rights reserved.

Liposomes are a promising delivery system for bioactives in food and nutraceuticals. Their practical application is limited by their physical and chemical instability caused by extrinsic factors. The physical stability of liposomes of three different sizes coated with cold water fish skin gelatin was assessed during osmotic dehydration at 2, 21 and 70 °C. Soy lecithin was used to prepare 1 % liposomal dispersions. The size distribution was controlled with high pressure homogenization (1500 bar) and extrusion through polycarbonate membrane (3 and 0.8 μm). Fish gelatin was adsorbed to the interface to make secondary liposomes. Liposomal dispersions were osmotically dehydrated while monitoring the relative weight, size and rheological properties. The primary liposomes had an initial mean volume diameter (d4,3) of 0.09, 0.40 and 2.7 μm and a ζ-potential of −55 mV. Secondary liposomes were 0.11, 0.45 and 3.4 μm with a ζ-potential of 25 mV. The size of liposomes influenced the stability of liposomes, with the smallest liposomes being stable for 30 min, corresponding to 80 % of the initial weight, while the larger liposomes were already aggregated. Secondary liposomes were stable to 120 min for the smaller liposomes and to 150 min for the largest liposomes corresponding to 40 % of the initial weight. Stability increased during dehydration at 2 °C. Coating the liposomes increased the physical stability of the liposomal dispersions at all temperatures. The results show that cold water fish skin gelatin is a viable option to coat liposomes of a wide size range.

Hypothesis: This study investigated the influence of liquid-solid transition and particle size on the optical properties of nanoemulsions. The hypothesis was that the crystallization of lipid droplets influences the nanoemulsion appearance.Experiments: Liquid and solid nanoemulsions (10 wt% octadecane, 1-5 wt% sodium dodecylsulfate) were formed by high-pressure microfluidization (5000-28,500 psi) at 45 degrees C. Solid lipid nanoparticles were formed by cooling the nanoemulsions to 5 C and then heating to ambient temperature, whereas liquid nanoemulsions were formed by maintaining them at 25 degrees C.Findings: Results indicated that lipid nanoparticles ranging from 136 nm down to 36 nm were generated, and were stable to particle aggregation. The melting and onset temperatures of the nanoparticles decreased with decreasing particle diameter. Upon crystallization of the lipid, the absorbance increased by about 140% for nanoemulsions with 136 nm particle diameter, but only 5% for nanoemulsions with 36 nm particle diameter. These results were explained in terms of changes in refractive index upon droplet solidification that alter their scattering behavior. These results show that solidification of nanoemulsions results in a shift of the transparent-to-turbid transition regime. The practical consequences for emulsion manufacturers are that solid nanoemulsions must be smaller than liquid nanoemulsions to remain transparent. (C) 2015 Elsevier Inc. All rights reserved.

This study describes the assembly of colloidosomes by adsorbing solid lipid nanoparticles (SLN) onto the interfaces of oil-in-water emulsion droplets via electrostatic deposition technique. Oil-in-water emulsions (10% w/w corn oil, 1% w/w whey protein isolate in water) and SLN (10% octadecane, 1% sodium dodecyl sulfate in water) were prepared using a microfluidizer. The surface saturation concentration (Csat) of negatively charged SLN adsorbed onto the positively charged oil-in-water emulsions (at oil droplet concentration of 0.5%) at pH3 was investigated by measuring ζ-potential, and particle size, as well as assessing the microstructure by optical microscopy. Each of these methods depicted Csat between 1.1–1.5% (w/w). The results were explained by calculating theoretical Csat using molecular forces acting between the adsorbed droplets as described by the DLVO theory. We demonstrated that the surface saturation of SLN on emulsion droplets depends on the particle size population.

Hypothesis: The purpose of this study was to find a suitable co-surfactant to replace non-food grade bile salts in solid lipid nanoparticle (SLN) formulations. The hypothesis was that the molecular structure and physical properties of co-surfactant modulate the stabilization of SLNs upon polymorphic transition.Experiments: Tristearin SLNs were prepared by using two main surfactants: saturated high-melting lecithin, and unsaturated low-melting lecithin. As co-surfactants we used sodium taurodeoxycholate (i.e. bile salt), Pluronic F68, Tween 60 and 80, and amino acids tyrosine, tryptophan, and phenylalanine. The influence of co-surfactants on crystallization behavior and physical stability of SLNs was investigated by differential scanning calorimetry and static light scattering, respectively.Findings: The results showed that the aromatic amino acids had optimal structures and properties to act as effective co-surfactants in SLNs. Our study suggests that ideal co-surfactants are amphiphilic with pronounced hydrophobic areas, but highly water soluble so that they can have a reservoir of molecules readily available for interfacial stabilization. They adsorb fast to the interfaces, but without inducing polymorphic transition. This work demonstrates how the right structure can facilitate the desired function. (C) 2014 Elsevier Inc. All rights reserved.

A major challenge for food and pharmaceutical industries is the engineering of nanostructures that can efficiently encapsulate bioactive compounds with enhanced physical and chemical stability, and high load. The influence of surfactant properties on the physical and chemical stability of (i) nanostructured lipid carriers (NLC) containing tristearin and ω-3 fish oil, (ii) tristearin solid lipid nanoparticles (SLN), and (iii) ω-3 fish oil-in-water emulsions was investigated. As surfactants we used low (LM)- and high-melting (HM) lecithins. Results indicated that the presence of fish oil reduced the crystallisation temperature, melting temperature, and melting enthalpy of tristearin. NLC stabilized with HM-lecithin inhibited the oxidation of ω-3 fatty acids ≥90% compared to those stabilized with LM-lecithin. This was attributed to the solidified surfactant layer of HM-lecithin inducing crystallisation of the shell by interfacial heterogeneous nucleation. The results showed that the saturated HM-lecithin was the key in controlling the crystallisation behaviour, and thereby enabled the formation of oxidatively and physically stable lipid nanoparticles.

Emulsions are systems that consist of two or more liquid phases that are partially or completely immiscible with one liquid being dispersed in the other in the form of droplets. Emulsions constitute an important product class in various industries including the food, chemical and pharmaceutical industries. Emulsions are inherently unstable since the two immiscible liquids have a tendency to phase separate over time in order to minimize the thermodynamically unfavorable interaction between the two or more molecular species. As such, the kinetic stability of emulsions that is their ability to resist phase separation due to destabilization processes such as flocculation, coalescence, or Ostwald ripening is of key importance to manufacturers.

The use of ultrasound in the food industry has increased in the last decades. Ultrasound has been used both to analyze food structure and composition at low ultrasonic intensities and high frequencies and to modify ingredients at high ultrasonic intensities and low frequencies. Application of the latter is referred to as high-intensity (power) ultrasonication and is generally carried out at frequencies of =0.1 MHz and ultrasonic intensities of 10–100 W cm−2. In the food industry, power ultrasonication has proved to be a highly effective food processing and preservation technology, and use of high-intensity ultrasound with or without heat may be used, for example, to denature enzymes, aid in the extraction of valuable compounds from plants and seeds, tenderize meat, and homogenize or disperse two-phase systems such as emulsions or suspensions (Mason et al., 1996).