Impact of different sequences of mechanical and thermal processing on the rheological properties of Porphyridium cruentum and Chlorella vulgaris as functional food ingredients.

Microalgae are a promising and sustainable source for enhancing the nutritional value of food products. Moreover, incorporation of the total biomass might contribute to the structural properties of the enriched food product. Our previous study demonstrated the potential of Porphyridium cruentum and Chlorella vulgaris as multifunctional food ingredients, as they displayed interesting rheological properties after applying a specific combination of mechanical and thermal processing. The aim of the current study was to investigate the impact of a different sequence of high pressure homogenization (HPH) and thermal processing on the thickening and gelling potential of these microalgal biomasses in aqueous suspensions. Thermal processing largely increased the gel strength and viscosity of both microalgae, which was ascribed to larger and stronger aggregates as a result of partial solubilization of polymers, while subsequent HPH generally reduced the rheological properties. Interestingly, large amounts of intact cells were still observed for both microalgae when HPH was performed after a thermal treatment, irrespective of the applied homogenization pressure, implying that cell disruption was hindered by the preceding thermal treatment. Although thermal processing was regarded as the most effective processing technique to obtain increased rheological properties, the combination with a preceding HPH treatment should still be considered when cell disruption is desired, for instance to increase the bioavailability of intracellular components. Finally, biomass of P. cruentum showed the largest potential for use as a structuring agent, as the gel strength and viscosity in thermally treated suspensions of this microalga were about 10 times higher than for C. vulgaris.

Isothermal Crystallization Kinetics of Palm Oil as Influenced by Addition of a Commercial Phytosterol Ester Mixture.

In literature there is good agreement on the health-promoting effects of phytosterols. However, addition of phytosterol esters (PEs) to lipid (containing food products) may influence its crystallization behavior. This study investigated the crystallization kinetics of palm oil (PO) after addition of PEs in high concentrations (≥10%). The isothermal crystallization of the PE-PO blends was analyzed at a temperature of 20 °C and at a supercooling of 18.7 °C using differential scanning calorimetry and time-resolved synchrotron X-ray diffraction. At increasing PE concentrations, PO crystallization at an isothermal temperature of 20 °C started later and was slower and a smaller amount of crystals were formed. Furthermore, a delay in polymorphic transition from α to ß' was observed. When the blends were isothermally crystallized at a supercooling of 18.7 °C, only two of these effects remained: the delay in polymorphic transition and the decrease in crystalline content.

The effect of adding a commercial phytosterol ester mixture on the phase behavior of palm oil.

The objective of this study was to investigate in depth the non-isothermal crystallization and melting behavior of binary blends of palm oil (PO) with a commercial, multi-component phytosterol ester (PE) mixture. DSC and time-resolved synchrotron X-ray diffraction (XRD) experiments were conducted on blends with a PE concentration from 0 to 100% at intervals of 10% for DSC and 20% for XRD. Based on XRD, two different ordered structures were identified in pure the PEs. The structure designated as PEx was truly crystalline and needed a very high degree of supercooling for its nucleation from the melt. The structure designated PEy formed without supercooling and showed long-range order with multiple reflections at small angles but only one broad reflection at high angle, typical of liquid crystalline samples. Furthermore, PEy had a high tolerance for molecules of different chemical nature. In the PE-PO blends no other ordered structures were formed other than the ones observed in the pure PEs and PO. The peaks in the DSC runs of the PE-PO blends were linked to transitions of the different polymorphic forms. All structural information of the binary blends as a function of concentration and temperature was collected in morphology maps. The binary blends exhibited eutectic characteristics visualized in the morphology maps with a eutectic point at 40% PEs.

Echium oil is not protective against weight loss in head and neck cancer patients undergoing curative radio(chemo)therapy: a randomised-controlled trial.

BACKGROUND: Therapy-induced mucositis and dysphagia puts head and neck (H&N) cancer patients at increased risk for developing cachexia. Omega-3 fatty acids (n-3 FA) have been suggested to protect against cachexia. We aimed to examine if echium oil, a plant source of n-3 FA, could reduce weight loss in H&N cancer patients undergoing radio(chemo)therapy with curative intent. METHODS: In a double-blind trial, patients were randomly assigned to echium oil (intervention (I) group; 7.5 ml bis in die (b.i.d.), 235 mg/ml α-linolenic acid (ALA) + 95 mg/ml stearidonic acid (SDA) + 79 mg/ml γ-linolenic acid (GLA)) or n-3 FA deficient sunflower oil high oleic (control (C) group; 7.5 ml b.i.d.) additional to standard nutritional support during treatment. Differences in percentage weight loss between both groups were analysed according to the intention-to-treat principle. Erythrocyte FA profile, body composition, nutritional status and quality of life were collected. RESULTS: Ninety-one eligible patients were randomised, of whom 83 were evaluable. Dietary supplement adherence was comparable in both groups (median, I: 87%, C: 81%). At week 4, the I group showed significantly increased values of erythrocyte n-3 eicosapentanoic acid (EPA, 14% vs -5%) and n-6 GLA (42% vs -20%) compared to the C group, without a significant change in n-6 arachidonic acid (AA, 2% vs -1%). Intention-to-treat analysis could not reveal a significant reduction in weight loss related to echium oil consumption (median weight loss, I: 8.9%, C: 7.6%). Also, no significant improvement was observed in the other evaluated anthropometric parameters. CONCLUSIONS: Echium oil effectively increased erythrocyte EPA and GLA FAs in H&N cancer patients. It failed however to protect against weight loss, or improve nutritional parameters. TRIAL REGISTRATION: ClinicalTrials.gov Identifier NCT01596933.

Stability of omega-3 LC-PUFA-rich photoautotrophic microalgal oils compared to commercially available omega-3 LC-PUFA oils.

Microalgae are the primary producers of omega-3 LC-PUFA, which are known for their health benefits. Their oil may thus be a potential alternative for fish oil. However, oxidative and hydrolytic stability of omega-3 LC-PUFA oils are important parameters. The purpose of this work was therefore to evaluate these parameters in oils from photoautotrophic microalgae (Isochrysis, Phaeodactylum, Nannochloropsis gaditana, and Nannochloropsis sp.) obtained with hexane/isopropanol (HI) and hexane (H) and compare them with commercial omega-3 LC-PUFA oils. When the results of both the primary and secondary oxidation parameters were put together, it was clear that fish, tuna, and heterotrophic microalgae oil are the least oxidatively stable oils, whereas krill oil and the microalgae oils performed better. The microalgal HI oils were shown to be more oxidatively stable than the microalgal H oils. The hydrolytic stability was shown not to be a problem during the storage of any of the oils.

Impact of feed supplementation with different omega-3 rich microalgae species on enrichment of eggs of laying hens.

Four different omega-3 rich autotrophic microalgae, Phaeodactylum tricornutum, Nannochloropsis oculata, Isochrysis galbana and Chlorella fusca, were supplemented to the diet of laying hens in order to increase the level of omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA) in egg yolk. The microalgae were supplemented in two doses: 125 mg and 250 mg extra n-3 PUFA per 100g feed. Supplementing these microalgae resulted in increased but different n-3 LC-PUFA levels in egg yolk, mainly docosahexaenoic acid enrichment. Only supplementation of Chlorella gave rise to mainly α-linolenic acid enrichment. The highest efficiency of n-3 LC-PUFA enrichment was obtained by supplementation of Phaeodactylum and Isochrysis. Furthermore, yolk colour shifted from yellow to a more intense red colour with supplementation of Phaeodactylum, Nannochloropsis and Isochrysis, due to transfer of carotenoids from microalgae to eggs. This study shows that besides Nannochloropsis other microalgae offer an alternative to current sources for enrichment of hen eggs.

Crystallization behavior and texture of trans-containing and trans-free palm oil based confectionery fats.

The objective of this study was to gain insight into the role of trans fatty acids in determining the crystallization behavior and texture of palm-based confectionery fats. Therefore, the isothermal crystallization behavior of two series, each of three fats, one trans-containing and one trans-free, was examined by pNMR, DSC, and rheology. Furthermore, the hardness of these samples was examined at three different storage times at 10 degrees C. All of the trans free samples showed a two-step crystallization at 10 degrees C which is hypothesized to be an alpha-mediated beta' crystallization for two of the samples and a fractionated crystallization in the beta' polymorph for the third, while the trans-containing fats crystallized in a single step, probably a direct beta' crystallization. The trans-containing fat series clearly crystallized faster than the trans-free fat series and also yielded higher hardness values at all storage times investigated. The presence of trans fatty acids seems to reduce the effect of compositional variations on the crystallization process. For the trans free fats, chemical composition was much more critical in determining the crystallization rate, the SFC, and the final hardness value.

Relationship between crystallization behavior, microstructure, and macroscopic properties in trans-containing and trans-free filling fats and fillings.

The objective of this study is to investigate the architecture to feature physical functionality of filling fats. This means an investigation of the different structure levels (crystallization, microstructure, macrostructure, etc.) that lead to good technological functionality. The isothermal crystallization behavior of two filling fats (one trans-containing and one trans-free) was examined by differential scanning calorimetry and microscopy. Furthermore, the hardness of the samples was examined after cooling in a water bath at two different temperatures and at three different storage times. The trans-containing filling fat crystallized faster and in smaller crystals as compared to the trans-free filling fat. The crystallization behavior of the trans-free filling fat was more complex, with the formation of different polymorphic forms. The hardness of the fillings was not only governed by the amount of solid fat present in the network but also by the structure of this network. The filling matrix components seem to have a pronounced influence on the microstructure and thus on the macroscopic properties.

Relationship between crystallization behavior, microstructure, and macroscopic properties in trans containing and trans free coating fats and coatings.

The objective of this study is to gain further understanding into the relationship between crystallization behavior, microstructure, and macroscopic properties in coating fats. The isothermal crystallization behavior of two coating fats (one trans containing and one trans free) was examined, both as pure fats and in coatings, by DSC and microscopy. Furthermore, the hardness of the samples was examined after cooling in a water bath at two different temperatures and at three different storage times. Both fats seemed to show an alpha-mediated beta' crystallization at lower temperatures and a direct beta' crystallization at higher temperatures. The trans free coating fat clearly crystallized faster and in smaller crystals. The hardness was governed not only by the amount of solid fat present in the network but also by the structure of this network. The coating matrix components seem to have a pronounced influence on the microstructure and thus on the macroscopic properties.