Effect of microfluidization on bioaccessibility of carotenoids from Chlorella ellipsoidea during simulated digestion

Developing industry-scale microfluidization for cell disruption, biomolecules release and bioaccessibility improvement of Chlorella pyrenoidosa

To facilitate biomolecules extraction and bioaccessibility of Chlorella pyrenoidosa, a novel industry-scale microfluidization (ISM) was used to disrupt cells effectively. Microscope images showed ISM damaged cell integrity, disorganized cell wall structure, pulverized cell membrane and promoted the release of intracellular components. The decrease of particle size and the increase of ζ-potential also confirmed the cell disruption. The cell breakage ratio of sample treated at 120 MPa was 98%. Compared with untreated samples, total soluble solid content and protein extraction rate of the sample treated at 120 MPa increased by 2 °Brix and 12%. Protein was degraded by ISM, the release of intracellular protein and the reduction of molecular weight increased protein digestibility by 20% in in vitro gastric phase. Lipid yield and chlorophyll b content were also increased by ISM. These results provided a new solution to cell disruption of microalgae and expanded the application field of ISM.

Impact of Regular Intake of Microalgae on Nutrient Supply and Cardiovascular Risk Factors: Results from the NovAL Intervention Study

A 14-day randomized controlled study with a parallel design was conducted with 80 healthy participants. Intervention groups I (IG1) and II (IG2) received a defined background diet and consumed a smoothie enriched with either 15 g of Chlorella dry weight (d.w.) or 15 g of Microchloropsis d.w. daily. Control group II (CG2) received a defined background diet without the smoothie. Control group I (CG1) received neither. Blood samples and 24-h urine were collected at the beginning and the end of the study. Serum concentrations of 25-hydroxyvitamin D3, vitamin D3, selenium, iron, ferritin, transferrin saturation, total cholesterol, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, non-HDL cholesterol and the LDL-cholesterol/HDL cholesterol ratio decreased in IG1 (p < 0.05), while 25-hydroxyvitamin D2 increased (p < 0.05). In IG2, vitamin D3, 25-hydroxyvitamins D2 and D3 decreased (p < 0.05), while concentrations of fatty acids C20:5n3 and C22:5n3 increased. Serum and urine uric acid increased in IG1 and IG2 (p < 0.05). Microchloropsis is a valuable source of n3 fatty acids, as is Chlorella of vitamin D2. Regular consumption of Chlorella may affect the iron and selenium status negatively but may impact blood lipids positively. An elevated uric acid concentration in blood and urine following the regular consumption of microalgae poses potential risks for human health.

Bioaccessibility of microalgae-based carotenoids and their association with the lipid matrix

The composition of microalgae can contribute to nutritious and functional diets. Among the functional compounds, carotenoids are in focus since positive effects on human health have been established, which are in turn related to their bioaccessibility. In addition to essential nutrients, our hypothesis was that microalgae biomasses could be used as sources of bioaccessible carotenoids. Thus, this study determined for the first time the bioaccessibility of carotenoids from biomass of Scenedesmus bijuga and Chlorella sorokiniana and their possible relationship with the lipid composition of the matrix. The samples were submitted to in vitro digestion protocol, and carotenoids were determined by HPLC-PDA-MS/MS. Individual bioaccessibility of carotenoids was ≥ 3.25%. In general, compounds in their cis conformation were more bioaccessible than trans; and total carotenes more than total xanthophylls. Twelve compounds were bioaccessible from the biomass of S. bijuga, and eight in C. sorokiniana. In S. bijuga, the bioaccessibility of total carotenoids was 7.30%, and the major bioaccessible carotenoids were 9-cis-β-carotene (43.78%), 9-cis-zeaxanthin (42.30%) followed by 9-cis-lutein (26.73%); while in C. sorokiniana, the total bioaccessibility was 8.03%, and 9-cis-β-carotene (26.18%), all-trans-β-carotene (13.56%), followed by 13-cis-lutein (10.71%) were the major compounds. Overall, the total content of lipids does not influence the bioaccessibility of total carotenoids. Still, the lipid composition, including structural characteristics such as degree of saturation and chain length of the fatty acid, impacts the promotion of individual bioaccessibility of carotenes and xanthophylls of microalgae. Finally, the results of this study can assist the development of microalgae-based functional food ingredients and products.

In vitro bioaccessibility of macular xanthophylls from commercial microalgal powders of Arthrospira platensis and Chlorella pyrenoidosa

The bioaccessibility of the major carotenoids present in two commercial microalgal supplements in powder form was investigated through a standardized in vitro digestion method. The dried biomass of Arthrospira platensis contained β-carotene (36.8 mg/100 g) and zeaxanthin (20.8 mg/100 g) as the main carotenoids as well as a high content of saturated fatty acids (61% of total fatty acids), whereas that of Chlorella pyrenoidosa was rich in lutein (37.8 mg/100 g) and had a high level of unsaturated fatty acids (65% of total fatty acids). In the case of the latter, lutein bioaccessibility was not statistically enhanced after the replacement of porcine bile extract with bovine bile extract in the in vitro digestion protocol and after the addition of coconut oil (17.8% as against to 19.2% and 19.2% vs. 18.5%, respectively). In contrast, the use of bovine bile extract along with co-digestion with coconut oil significantly enhanced the bioaccessibility of zeaxanthin from A. platensis, reaching the highest bioaccessibility of 42.8%.

Insights on the intestinal absorption of chlorophyll series from microalgae

The bioaccessibility and subsequent uptake by Caco-2 human intestinal cells of chlorophyll pigments from Scenedesmus obliquus were determined for the first time. In order to evaluate the impact of different types of the matrix on bioaccessibility of chlorophyll from microalgae, three different products were evaluated: isolated chlorophyll extract (ICE); wet ultrasonicated biomass (WUB); and whole dried biomass (WDB). The samples were submitted to in vitro digestion model according to the INFOGEST protocol, and Caco-2 cells determined the intestinal uptake. Chlorophyll pigments were determined by HPLC-PDA-MS/MS. A total of ten chlorophyll pigments (8,318.48 µg g^-1) were separated in S. obliquus biomass, with chlorophyll a (3,507.76 µg g^-1) and pheophytin a' (1,598.09 µg g^-1) the major ones. After in vitro digestion, all tested products showed bioaccessible chlorophylls. However, the total bioaccessibility results were as follows: ICE (33.45%), WUB (2.65%), WDB (0.33%). Five compounds were bioaccessible in ICE, three in WUB, and one in WDB. The hydroxypheophytin a showed the highest bioaccessibility (212%) in ICE, while pheophytin a' in WUB (11%) and WDB (2%). As a result, bioavailability estimates of ICE using the Caco-2 cell showed hydroxypheophytin a (102.53%), followed by pheophytin a' (64.69%) as the chlorophyll pigments most abundant in intestinal cells. In summary, from a nutritional perspective, these three types of the matrix (WDB, WUB, and ICE) influence the promotion of chlorophyll bioaccessibility. In this way, the data suggest that chlorophylls bioaccessibility from ICE is greater than that in WDB and WUB. Therefore, ICE should be considered a product that provides bioavailable chlorophyll and could be the best choice, such as ingredients in the development of functional foods chlorophyll-based.

A Brief Overview of Dietary Zeaxanthin Occurrence and Bioaccessibility

As it exhibits no provitamin A activity, the dietary intake of zeaxanthin is not considered essential. However, its contribution to ocular health has long been acknowledged. Numerous publications emphasize the importance of zeaxanthin alongside lutein in ocular diseases such as cataracts and age-related macular degeneration which constitute an important health concern, especially among the elderly. Considering that the average dietary ratio of lutein to zeaxanthin favors the first, more bioaccessible food sources of zeaxanthin that can hinder the development and progression of the above-mentioned disorders are of great interest. In this paper, a brief overview of the more recent state of knowledge as regards dietary sources together with their respective zeaxanthin bioaccessibility assessed through a standardized in vitro digestion method was provided.

Effect of high-pressure microfluidization on nutritional quality of carrot (Daucus carota L.) juice

In this study, the effect of high-pressure microfluidization on the colour and nutritional qualities of the orange carrot juice was investigated. The juice was processed at three different pressures (34.47 MPa, 68.95 MPa and 103.42 MPa) with three different passes (1, 2 and 3 passes). After that, total phenolic content (TPC), antioxidant activity, carotenoids, color properties, and total soluble solids content of the processed carrot juice were evaluated. As a result, no specific trends in TPC and antioxidant activity of the juice were observed through the variations of processing conditions. However, microfluidization significantly (p < 0.05) improved the carotenoids content in carrot juice. With increasing number of pass, concentrations of β-carotene and lutein had increased significantly. Similarly, increasing process pressure initially increased carotenoid content significantly (up to 68.95 MPa), further increase pressure to 103.42 MPa did not cause significant changes in carotenoid concentration. Furthermore, color properties such as lightness, redness, yellowness, and chroma value were reduced significantly with the increase of pressure and the number of passes. The results indicated that high-pressure microfluidization could be used as a novel alternative nonthermal technology to heat pasteurization to improve the color and nutritional qualities in orange carrot juice, resulting in a desirable, high-quality juice for consumers.

Microfluidization trends in the development of nanodelivery systems and applications in chronic disease treatments

Plant bioactive compounds are known for their extensive health benefits and therefore have been used for generations in traditional and modern medicine to improve the health of humans. Processing and storage instabilities of the plant bioactive compounds, however, limit their bioavailability and bioaccessibility and thus lead researchers in search of novel encapsulation systems with enhanced stability, bioavailability, and bioaccessibility of encapsulated plant bioactive compounds. Recently many varieties of encapsulation methods have been used; among them, microfluidization has emerged as a novel method used for the development of delivery systems including solid lipid nanocarriers, nanoemulsions, liposomes, and so on with enhanced stability and bioavailability of encapsulated plant bioactive compounds. Therefore, the nanodelivery systems developed using microfluidization techniques have received much attention from the medical industry for their ability to facilitate controlled delivery with enhanced health benefits in the treatment of various chronic diseases. Many researchers have focused on plant bioactive compound-based delivery systems using microfluidization to enhance the bioavailability and bioaccessibility of encapsulated bioactive compounds in the treatment of various chronic diseases. This review focuses on various nanodelivery systems developed using microfluidization techniques and applications in various chronic disease treatments.

Cell-wall disruption and lipid/astaxanthin extraction from microalgae: Chlorella and Haematococcus

Recently, biofuels and nutraceuticals produced from microalgae have emerged as major interests, resulting in intensive research of the microalgal biorefinery process. In this paper, recent developments in cell-wall disruption and extraction methods are reviewed, focusing on lipid and astaxanthin production from the biotechnologically important microalgae Chlorella and Haematococcus, respectively. As a common, critical bottleneck for recovery of intracellular components such as lipid and astaxanthin from these microalgae, the composition and structure of rigid, thick cell-walls were analyzed. Various chemical, physical, physico-chemical, and biological methods applied for cell-wall breakage and lipid/astaxanthin extraction from Chlorella and Haematococcus are discussed in detail and compared based on efficiency, energy consumption, type and dosage of solvent, biomass concentration and status (wet/dried), toxicity, scalability, and synergistic combinations. This report could serve as a useful guide to the implementation of practical downstream processes for recovery of valuable products from microalgae including Chlorella and Haematococcus.

Effect of the interaction of heat-processing style and fat type on the micellarization of lipid-soluble pigments from green and red pungent peppers (Capsicum annuum)

The high diversity of carotenoids and chlorophylls in foods contrasts with the reduced number of pigments that typically are investigated in micellarization studies. In this study, pepper samples (raw and heat-treated) contained 68 individual pigments, but only 38 of them were micellarized after in vitro digestion. The micellarization of pigments was majorly determined by the interaction effect of processing style (food matrix effect) and fat type (saturated and unsaturated). The highest micellarization was observed with raw peppers. Unsaturated fat increased the micellarization of carotenoid esters, while the impact of fat on the micellarization of free carotenoids seemed to be dependent on pigment structure. The micellarization efficiency was diminished as the esterification level of carotenoids increased. The type of fatty acid moiety and the polarity of the carotenoids modulated their micellarization. Chlorophylls were transformed into pheophytins by heat-processing and digestion, with the pheophytins being stable under gastrointestinal conditions. Micellarization of pheophytins was improved by fat.