Optimizing Docosahexaenoic Acid (DHA) Production by Schizochytrium sp. Grown on Waste Glycerol

The aim of this study was to optimize biomass and docosahexaenoic acid (DHA) production by Schizochytrium sp. grown on waste glycerol as an organic carbon source. Parameters having a significant effect on biomass and DHA yields were screened using the fractional Plackett–Burman design and the response surface methodology (RSM). Schizochytrium sp. growth was most significantly influenced by crude glycerin concentration in the growth medium (150 g/dm3), process temperature (27 °C), oxygen in the bioreactor (49.99% v/v), and the concentration of peptone as a source of nitrogen (9.99 g/dm3). The process parameter values identified as optimal for producing high DHA concentrations in the biomass were as follows: glycerin concentration 149.99 g/dm3, temperature 26 °C, oxygen concentration 30% (v/v), and peptone concentration 2.21 g/dm3. The dry cell weight (DCW) obtained under actual laboratory conditions was 66.69 ± 0.66 g/dm3, i.e., 1.27% lower than the predicted value. The DHA concentration obtained in the actual culture was at 17.25 ± 0.33 g/dm3, which was 3.03% lower than the predicted value. The results obtained suggest that a two-step culture system should be employed, with the first phase focused on high production of Schizochytrium sp. biomass, and the second focused on increasing DHA concentration in the cells.

INVESTIGATION OF THE INFLUENCE OF GLYCERIN ON RHEOLOGICAL CHARACTERISTICS OF MARZIPAN PASTES WITH DRY MINERALIZED WHEY

There is studied the influence of glycerin on rheological characteristics of marzipan pastes with dry demineralized whey (DDW) for determining its rational concentration in the composition of decorative semi-products PKV and MFV. PKV – marzipan pastes with DDW, used for covering confectionary products and as an interlayer; MFV – marzipan pastes with DDW, used for making candies and modeling figured products. According to research results, it has been established, that an increase of a glycerin concentration in the composition of model mixtures of marzipan pastes PKV (20 % of DDW) and MFV (30 % of DDW) results in decreasing deformation characteristics of a reversible type. Irreversible deformation is constant and doesn’t depend on glycerin concentration. According to results of the analysis of main rheological constants by a diapason of glycerin concentrations, there has been established a gradual decrease of indices of a highly elastic and conventionally instant resilience module of model compositions of marzipan pastes PKV (20 % of DDW) and MFV (30 % of DDW). Viscosity indices of a resilient aftereffect and pliability gradually grow with an increase of a glycerin concentration in the composition of model marzipan pastes PKV (20 % of DDW) and MFV (30 % of DDW). Research results testify that the use of glycerin in the composition of marzipan pastes PKV (20 % of DDW) and MFV (30 % of DDW) gives a possibility to increase their elasticity and softness, at that keeping high forming properties. The conducted studies have proved the availability of producing marzipan pastes with DDW and glycerin. There has been substantiated the rational content of glycerin in the composition of marzipan pastes with DDW that allows to provide given (desirable) rheological characteristics. The rational concentration of glycerin in the composition of marzipan pastes PKV (20 % of DDW), used for covering floury and confectionary products and as an interlayer is 5 % of the total mass of recipe components. The rational concentration of glycerin in the composition of marzipan pastes MFV (30 % of DDW), used for making candies, modeling figured products is 5 % of the total mass of recipe components. An improved technological solution doesn’t complicate the general technological process and doesn’t need the additional technical equipment. Rheological characteristics of the developed marzipan pastes correspond to directions of the technological destination and allow to decorate floury confectionary products with different levels of technological complication, providing the maximal beauty of ready products.

Efek Gliserin sebagai Humectan Terhadap Sifat Fisik dan Stabilitas Vitamin C dalam Sabun Padat

Glycerin is a humectant that is used frequently for cosmetics, especially in soaps. This study was conducted to determine the influence glycerin on the physical properties of glycerin soap including pH, soap hardness, foam stability, and also on the stability of vitamin C in the soap during 8 weeks storage. Vitamin C is formulated in soap with various concentrations of glycerin i.e 5%, 10% and 20%. Evaluation of the soap preparations include a pH test, soap hardness, foam stability test and evaluation on the stability of vitamin C for 8 weeks and the results obtained will be statistically analyzed using SPSS version 16 for windows by the Kruskal-Wallis method on the results test of pH and soap hardness, and using one way ANOVA method for evaluating foam stability. The results showed that glycerol did not significant influence on the pH value of soap with a significance value of P = 0.26 0.05, while increasing the concentration of glycerin in the soap increased products softness. The foam stability testing showed that the difference in the concentration of glycerin on soap had no significant effect on improving the stability of foam. The best foam stability was found in vitamin C soap containing glycerine 10%. Glycerin also affected the stability of vitamin C in the soap. The stability of vitamin C is increased related to the increasing glycerin concentration in soap as demonstrated in formula III, which contained 20% glycerin and had 49.48% reducing in level of vitamin C, while the soap containing glycerine 5 % and 10%, had decreased 77.98% and 60.67% respectively in level of vitamin C during the storage period of 8 weeks.

The influence of the glycerin concentration on the porous structure of ferritic stainless steel obtained by anodization

Anodizing of ferritic stainless steel has been used for decoration purposes to obtain a barrier effect. The most commonly used electrolyte for this process is INCO (5M H₂SO₄ + 2,5M CrO₃). INCO electrolyte with glycerin addition induces the formation of ordered porous structures, because glycerin reduces the electrolyte conductivity. Ferritic stainless steel was anodized in electrolyte composed by 2M H₂SO₄ with glycerin addition in different concentrations, without chromium oxide addition. It was observed that the addition of 90 v/v% glycerin promoted a reduction in the electrolyte conductivity, which caused an increase in the anodizing potential. The glycerin addition to the electrolyte diminished the oxide dissolution in the electrolytic solution, promoting the formation of an oxide with an ordered porous structure.

Preparation and Characterization of Chitosan Edible Film

The influence of factors, including different raw material ratio, drying temperature, concentration of glycerol and degassing time, on properties of chitosan edible film was studied. The results showed that higher mechanical properties of films could be achieved when chitosan and glycerin concentration were 1.5% and 0.5% respectively, and dried temperature was 55°C. Addition of proper amount of plasticizer could improve the properties of film.