SUGGESTION FOR AN OPTIMAL MODEL FOR E.coli, S. aureus AND C. albicans PRESERVATION AT A STORAGE TEMPERATURE IN THE RANGE OF 4°C TO -20°C

The low temperature in the storage processes can vary in the range of +4°C to -80°C and even lower, using liquid nitrogen. Depending on this, the time for which we expect the microbial culture to remain viable also changes. Agar slant culture, covered with oil, stab culture, saline suspension, glycerol and DMSO preservation, drying on silica gel, drying on soil, sterile water, lyophilization, cryopreservation, etc. are methods employed for the preservation of microorganisms. However, the choice of method to be used depends on the type of microorganism, the purpose of storage, and duration of preservation. The aim of the study is to compare storage techniques using semisolid agar and cultivation at 4°C and using BHI broth with glycerol and cultivation at -20°C. These are two commonly used and accessible methods for bacteria and yeast preservation. After performing the storage procedure for a total of 18 strains of S. aureus, E. coli and C. albicans, we re-cultivated them after two and six months of preservation. From the obtained results, we can conclude that the storage of bacteria at 4°C on semisolid agar for up to 8 weeks is successful, in C. albicans, one of the tested six strains did not survive. After 6 months, another strain of the yeasts did not show growth, as well as one of the sixth E. coli strains. Storing microbes at -20°C with a cryoprotectant has proven to be a more successful method. This was an expected result, and other authors commented that lower storage temperatures provide longer life for microorganisms.

Aloe vera Gel Drying by Refractance Window®: Drying Kinetics and High-Quality Retention

In most cases, conventional drying produces inferior quality products and requires higher drying times. A continuous pilot Refractance Window® equipment was used to dry Aloe vera gel slabs of 5 and 10 mm thick at 60, 70, 80, and 90 °C, seeking a dry product with high-quality retention. Based on five empirical models, drying kinetics, diffusion coefficient, and activation energy were analyzed. Midilli–Kuck was the best predicting model. Short drying times (55–270 min) were needed to reach 0.10 g water/g solid. In addition, the technique yielded samples with high rehydration capacity (24–29 g water/g solid); high retention of color (∆E, 3.74–4.39); relatively low losses of vitamin C (37–59%) and vitamin E (28–37%). Regardless of the condition of temperature and sample thickness, a high-quality dried Aloe vera gel could be obtained. Compared with other methods, Refractance Window® drying of Aloe vera achieved shorter drying times with higher quality retention in terms of color, vitamins C and E, and rehydration. Finally, the dried Aloe vera gel could be reconstituted to a gel close to its fresh state by rehydration.

Synthesis of Amorphous Zirconium Dioxide from Zirconyl Nitrate in Presence of Oxalic Acid

The article presents the results of studies on preparation of amorphous zirconium dioxide from zirconium nitrate by its hydrolysis in the presence of oxalic acid. It is determined that the balance of reagents taken for synthesis (1 ml 0,025 M ZrO(NO3)2 is 1.35 ml 4 M HOOC-COOH), and the optimum temperature of the received gel drying, which is 230 ̊С, is established, too. Morphology of the obtained ZrO2 samples was explored. It has been found that the calcining temperature is independent of the size and shape forming irregular agglomerates, consisting of smaller spherical particles, whose diameter varies between 50 and 300 nm. The X-ray analysis of the sample is represented, which showed a low degree of crystallinity of the substance. IR spectroscopy data showed the presence of zirconium dioxide-characteristic peaks on the IR spectrum. The same spectrum reflects the presence of a large amount of sorbed water in the obtained sample, as well as peaks characteristic of the gas adsorbed by the sample from the environment.

Silica –Gel Drying an Effective Preservation Technique for Value Addition of Orchid Flowers

Aim: Demand of dry flowers is cumulative day by day equally in national and international marketplace, as dried flowers have a prodigious potential as substitute of fresh flowers. This study aims to know the effect of Silica-gel drying technique on the quality of Orchid flowers. Study Design: The experimental research design was adopted and flowers were subjected to Silica-gel drying technique. Place and Duration of Study: The study was during October 2017- November 2020 in the Department of Family Resource Management, College of Community Science, Dharwad. Methodology: White and Purple Orchid were selected and collected from local growers. Moisture loss, time taken for drying, Effect on Qualitative parameters were statistically analyzed. Dried flowers were added value through application of color. Dyed flowers were used in development of products such as frames and potpourris. Cost of each product was estimated and 30 consumers selected randomly assessed the products for consumer acceptability. Results: The results reveal that in Silica-gel drying technique Orchid has taken 5 days to dry completely. Maximum moisture loss was 81-83 per cent. Color of Orchid had faded and appearance became lusterless. Hence value addition of color was required for these flowers. The most suitable value addition was Fabric paints, Oil and Spray paints. Some value added products were prepared from dried orchids such as frames and potpourris. The consumer acceptability of these products was extremely acceptable. Conclusion: The existing technology has the prospective to employ thousands of people especially to unemployed youths, Schools and College drop-outs, housewives and rural women’s as limitless aesthetic products can be shaped using dry flower technology, it can start up a small scale industry from their householdscan perform exceptionally to begin new markets. There is a necessity to generate adequate consciousness about the potential of this technology by workshops and seminars etc.

A simple method of drying polyacrylamide slab gels that eliminates cracking

The polyacrylamide slab gel is the most common gel format for analyzing protein samples by electrophoresis. Drying these gels is useful in many biological applications; for example, autoradiography, in which radiolabeled proteins are separated to enable their detection and identification. Dried protein gels can also serve as an ideal method of preserving the gel itself for permanent record-keeping and allowing densitometry at a convenient time. Here I describe a simple and highly reproducible gel-drying method that results in dried gels without the cracks that are frequently encountered with many existing gel-drying methods.