Assessment of the effect of growing techniques on changing of morphological characteristics of fruit bodies clusters PLEUROTUS OSTREATUS (JACQ.) P. KUMM

Abstract

The integrity of fruit bodies of the Oyster mushrooms is one of the important things for the efficiency of their storage. Fresh mushrooms can contain spores of different kind of bacteria which will start to grow when the tissue of fruit body will have broken during the packaging process. Ukrainian growers are using the standard size of polystyrene foam trays for the Oyster packaging but it does not match for the safety of soft mushroom surface. It reduces a food safety and total quality of mushroom during the keeping. One of solutions of this problem can become the possibility to grow clusters with assignment size. Data about effect of hole size for the yield and number of fruit bodies in the clusters of Pleurotus ostreatus var. florida is known. The purpose of our research was to determine effect of hole size (factor A: 50, 100 and 150 mm) and placement of substratum blocks on the shells (factor B: horizontal, vertical and diagonal position - angle of slope 60 °) for the size of clusters and biological efficiency of strain Pleurotus ostreatus 2301 IBK. This strain is a most popular in Ukraine due to fruit body morphology and good taste.  The culture of Pleurotus ostreatus 2301 IBK was obtained from the Institute of botany, NASU (Kiev). The culture was incubated on Malt Dextrose Yeast Agar (MDYA) at 24-26 °C. Grain mycelium was manufactured in condition of scienceindustrial company “GRYBNOY DOCTOR” (Melitopol) from mix barley, wheat and colza grain (10/9/1).  The substrate had been made by sold aerobic fermentation method from sunflower husks and barley straw (3/1) and was inoculated of grain mycelium - 3,5% from wet weight. The inoculated substrate was sealed in polyethylene bags
measuring 350 × 900 mm and film thickness of 70 μm. The average mass of the substrate blocks was 12430±230 g.   The substrate blocks were placed on shells and perforation holes were done according for the experimental variants with repeat in six times. The substrate blocks were incubated at 18±2 °С for support of the temperature in the center of blocks 26±2°С.  Light (200 lux) and reducing of temperature to 16±2 °С were used to initiate the formation of pinheads after the mycelium was fully grown on the substrate what was defined at 12 days of incubation. Relative humidity of air was 87±3%; CO2 concentration was 1050±50 ррm.  The morphological characteristics of clusters and biological efficiency were observed for the first flush of harvesting as most revealing of Oyster cultivation.  The first pinheads were recognized at 14-16-th day from inoculation at all variants of research. The first flush of harvesting lasted 5 days and difference between variants hadn't been noticed. The determined biological efficiency of Pleurotus ostreatus 2301 IBK strain in variant of horizontal position was on 10% less than other variants according U- criteria.  The relation between hole size at the substrate blocks and size of fruit bodies clusters was identified in all variants of research but it had a greater manifestation for horizontal position of substrate blocks. The width of clusters was more than their height for investigation in whole but in horizontal variant this difference was detected in 69-79 mm, whereas in other variant no more 40 mm. The correlation between hole size and size of fruit bodies clusters had a line dependency. This fact can give the possibility to predict the size of clusters for using at safety packaging. It will provide the long time storage of Oyster mushroom with high quality preservation.