Physico‐chemical properties and sensory evaluation of Pleurotus sajor caju powder as influenced by pre‐treatments and drying methods
Authors: Dunkwal V. , Jood S. , Singh S. 
Published: September 2007

Purpose

This article aims to focus on the food value of the mushroom. Because of its low calorific value and very high content of proteins, vitamins and minerals, mushrooms may contribute significantly in overcoming protein deficiency in developing countries like India.

Design/methodology/approach

Oyster (Pleurotus sajor caju) mushroom cultivated on two substrates i.e. wheat straw and brassica straw were procured. Freshly harvested and washed mushrooms were cut into small pieces. Sliced mushrooms were divided into four portions. Two portions were left untreated and dried using sun and oven drying methods. The third portion was blanched in boiling water at 100 °C for two mins, cooled immediately and drained. The blanched samples were divided into two portions. One portion was sun dried and another was oven dried. The fourth portion was soaked in solution of citric acid (0.25 percent) for 30 mins and drained. The steeped samples were divided into two portions. One portion was sun dried and another was oven dried. Each sample was dried from initial moisture content of 91 percent on fresh weight basis of the final moisture content 10 percent on dry weight basis. All the samples were ground to make fine powder. The untreated and treated samples were analysed for physico‐chemical properties and sensory evaluation by using standard methods.

Findings

Treated and untreated powders prepared from oyster (Pleurotus sajor caju) mushrooms grown on two substrates i.e. wheat and brassica straw were analysed for physical and chemical characteristics. Among the powders, T6 (steeped in 0.25 percent citric acid and oven dried) powder exhibited highest yield followed by untreated and blanched powders. On the other hand, untreated samples T1 (sun dried) and T4 (oven dried) showed higher browning index as compared to pretreated powders. Steeped samples (T3 and T6) from both type of mushrooms, irrespective of drying methods exhibited higher values of water retention capacity and swelling index as well as sensory attributes (colour, aroma and texture) In terms of chemical analysis, steeped samples from both types of mushrooms, irrespective of drying methods, exhibited higher contents crude protein, crude fibre and ash as compared to blanched powders. Blanching in hot water may cause leaching out of nutrients.

Practical implications

With regard to healthy benefits and medicinal value of mushroom, its production and consumption should be increased. However, mushroom production does not demand land, but helps in the bioconversion of potential pollutants like agro‐wastes to useful and nutritive food for human consumption, which is essential to a developing country like India.

Originality/value

The findings of this article may contribute significantly in overcoming protein deficiency in developing countries like India. Mushrooms have a low carbohydrate content, no cholesterol and are almost fat free. Therefore, they form an important constituent of a diet for a population suffering from atherosclerosis.