Hadiyanto

Bio: Hadiyanto is an academic researcher from Diponegoro University. The author has contributed to research in topics: Phycocyanin & Spirulina (genus). The author has an hindex of 6, co-authored 12 publications receiving 127 citations.

Comparative Study of Bioactive Substances Extracted from Fresh and Dried Spirulina sp.

Abstract: The increase consumption of natural substances has brought about in increasing demand on biological source, including Spirulina sp. This Spirulina sp. has been recognized to provide some natural substances such as natural colorant, source of vitamins, protein and some minerals. Different material state of Spirulina sp. in the form of fresh and dried form may cause different quantity and quality of natural substances in microalgae which posses a wide range of change including nutritional and natural substances. The aims of the study was to investigate the bioactive compounds resulted from different form of Spirulian sp (fresh and dried) quantitatively. The materials used were fresh and dried Spirulina sp which was extracted by ethanol. Analysis were subjected for phytochemical screening, flavoniod, phenolic acid and antioxidant activity (DPPH scavenging activity). The results showed that total flavonoid of fresh and dried are: 25.6615±1.62 and 110.1356±12.5 quercetin/gr extract; phenolic acid: 2.117±0.99 and 6.92±0.03 GAE/gr extract; IC50: 33.0755, respectively. Fresh sample of Spirulina platensis shows better results in bioactive compounds quantitatively and qualitatively compared to that of dried sample, and drying process at 40-50oC does not give any significant different on nutritional quality of dried sample of Spirulina platensis compared to fresh samples.

Kinetic study on the effects of sugar addition on the thermal degradation of phycocyanin from Spirulina sp.

Abstract: Phycocyanin is a source of antioxidants and natural colorants extracted from microalgae. It undergoes color, concentration, and antioxidant activity degradations during heating processes, such as in food processing. The effects of different kinds of sugars as stabilizer and elevation of temperature were studied. Glucose, sucrose, or fructose as stabilizer were mixed in phycocyanin solution, which was heated to 40 °C, 60 °C, and 80 °C for 60 min. Results showed that phycocyanin degraded significantly without any sugar addition. The addition of glucose could increase the activation energy by up to fourfold due to the polymerization of protein phycocyanin by sugar, and glucose could prevent damage of the phycocyanin structure. Phycocyanin underwent discoloration from bright blue to faint blue after heating at 80 °C. Fructose addition in phycocyanin could minimize color degradation at 80 °C, whereas glucose addition could increase the antioxidant activity of phycocyanin by decreasing IC50 up to 18.47%.

Encapsulation of phycocyanin-alginate for high stability and antioxidant activity

Abstract: The aim of this study was to obtain optimal condition of phycocyanin-alginate encapsulation, encapsulation efficiency and phycocyanin load, physicochemical properties of beads, in vitro release study, stability and antioxidant activity. The result product with alginate content 1,5% (w/v) and 2% (w/v) produced were in spherical shape than product with alginate content 2,5% (w/v) by ratio of phycocyanin 1:1. Increasing alginate content on encapsulation process will increase of encapsulation efficiency and phycocyanin load. In vitro released study showed that phycocyanin-alginate beads were more resistant in simulated gastric fluid, while rapidly release in simulated intestinal fluid. The antioxidant activity showed that phycocyanin antioxidant activity decreased after encapsulation process due to duration of storage and the possibility of a cracking which will cause reduced stability of phycocyanin.

Improvement of Stability and Antioxidant Activities by Using Phycocyanin - Chitosan Encapsulation Technique

Abstract: Encapsulation is a coating process to improve the stability of bioactive compounds. Phycocyanin with high antioxidant activity has been encapsulated with chitosan in microcapsules form. In this study aims to determine the best conditions in the encapsulation process using the extrusion method, characterization of the physicochemical properties of the microcapsules, antioxidant activity test using DPPH, in vitro release performance and evaluate the storage stability against temperature. The results of the encapsulation process is obtained: Na-TPP is better than Na-citrate as crosslinker and chitosan content 3% as a coating with ratio of chitosan to phycocyanin ratio 1: 1. Test of antioxidant activity also showed encapsulation with chitosan content 3% has the highest antioxidant activity. Morphological analysis microcapsules were found to have compact spherical shape with diameter range 900-1000 µm. In vitro release testing showed a quick release in an acidic environment (SGF) for 2 hours and slowly release under alkaline conditions (SIF) for 8 hours under mechanical stirring at 37°C. Phycocyanin much more stable against temperature during storage in microcapsules.

Photocatalytic activity of cobalt-doped zinc oxide thin film prepared using the spray coating technique

Abstract: We report on the synthesis, characterization and photocatalytic activity of ZnO: Co thin films coated onto amorphous glass substrates by sol–gel spray coating technique. Structural and optical properties of the films were evaluated using x-ray diffractometer (XRD) and uv–vis spectrophotometer (UV–Vis), respectively. XRD patterns showed that the samples exhibited hexagonal wurtzite structure. The addition of cobalt reduced the (0 0 2) peak. This doping also reduces transparency and optical band gap. The band gap (E g) markedly decreased from 3.20 eV to 3.00 eV for undoped ZnO and ZnO: Co with 10 mol% of doping concentration, respectively. Our thin films exhibited good structural, optical and photo cataytic properties. In this study, ZnO with 4 mol% of Co was observed to have the highest photocatalytic activity with methylene blue (MB) degradation of about 76.31% for 2 h under UV irradiation.

Microencapsulation 헤모글로빈 인공적혈구의 용혈

Abstract: The purpose of this study was to reduce the hemolysis of artificial red blood cells by extracting phospolipids from egg yolk through microencapsulation to evaluate the oxygen transfer rate of artificial red blood cells in an intravascular artificial lung device. In this study, hemosome was produced to encapsulate hemoglobin which extracted the red blood cell of bovine blood with phospolipids reduced egg yolk. The solution blended blood with hemosome at the rate of 4 to 1 and normal blood measured the oxygen transfer rate. The hemolysis of the microencapsulated artificial red blood cell measured less than the normal red blood cell through absorptivity. Due to the phospolipids enclosing the red blood cell to protect it, the produced hemosome operated at a higher oxygen transfer rate by reducing the demolition of hemoglobin. Consequently, hemolysis was observed to advance through micoencapsulation.

Phycocyanin and phycoerythrin: Strategies to improve production yield and chemical stability

Abstract: Phycocyanin and phycoerythrin are photosynthetic pigments extracted from microalgae with great biotechnological potential due to their intense colors, fluorescent properties and potential health benefits. Their principal applications are as nutritional supplements, natural colorants in foods and cosmetics, and as a reagent for immunological assays. However, the main challenges for their commercialization and implementation in food and cosmetic applications are their low yield during production and limited chemical instability. This review compares the use of different methods to increase biomass and pigment production yield, including the mechanisms associated with the microorganisms adaptative response to different light wavelengths. It also explores different methods reported to improve phycocyanin and phycoerythrin chemical stability and commercially available products.