~ 877 ~ The Pharma Innovation Journal 2019; 8(4): 877-881 ISSN (E): 2277- 7695 ISSN (P): 2349-8242 NAAS Rating: 5.03 TPI 2019; 8(4): 877-881 © 2019 TPI www.thepharmajournal.com Received: 02-02-2019 Accepted: 05-03-2019 Nadia Bashir Division of Food Science & Technology, Sher-e-Kashmir University of Science and Technology Jammu, Jammu and Kashmir, India Monika Sood Division of Food Science & Technology, Sher-e-Kashmir University of Science and Technology Jammu, Jammu and Kashmir, India Julie D Bandral Division of Food Science & Technology, Sher-e-Kashmir University of Science and Technology Jammu, Jammu and Kashmir, India Correspondence Nadia Bashir Division of Food Science & Technology, Sher-e-Kashmir University of Science and Technology Jammu, Jammu and Kashmir, India Effect of different drying methods on functional and sensory parameters of oyster mushroom (Pleurotus florida) Nadia Bashir, Monika Sood and Julie D Bandral Abstract This study was conducted to evaluate the effects of different drying methods viz., sun, solar, oven (40 °C), microwave (300 W), freeze (-60 °C) and osmotic drying (14% salt solution followed by drying at 40 °C) on functional properties and sensory attributes of oyster mushroom. Significant differences in functional parameters (browning index, rehydration ratio, water solubility index and bulk density) and sensory attributes (appearance, aroma, texture and overall acceptability) were observed in response to different drying techniques. The least browning index of 0.22 was reported for freeze dried mushroom while as microwave dried oyster mushroom recorded highest browning index of 0.62. The study concluded freeze drying as most suitable method of preserving mushroom with rehydration ratio, water solubility index, bulk density and overall acceptability value of 5.21, 1.91 per cent, 0.31 g per ml and 8.09, respectively. Keywords: Rehydration ratio, sensory attributes, bulk density, freeze drying, microwave drying 1. Introduction Oyster mushroom also known as “Dhingri” in India is a protein enriched food cultivated on lignocellulosic wastes. The oyster mushroom proteins are good quality proteins with good balance of essential amino acids thereby having potential to overcome protein energy malnutrition prevalent in developing countries (Deepalakshmi and Mirunalini, 2014) [13] . Furthermore, these are low in fat (0.8-7%) and are loaded with vital vitamins, minerals and dietary fiber (Randive, 2012) [39] . Pleurotus mushrooms also serve as source of functional ingredients like alkaloids, phenols, terpenes and antioxidants that offer health promoting benefits and therefore can act as functional foods (Thatoi and Singhdevsachan, 2014) [42] . The unique flavour of these oyster mushrooms, make them an integral parts of various dishes (Dunkwal et al. 2007) [14] . However, presence of large amounts of water (80-85%) makes them highly perishable with shelf life of only 2-3 days which is further reduced at temperatures of 18 °C and above. Of all the preservation methods, drying is an important preservation technique which can be employed for long term preservation of oyster mushroom as it offers a number of advantages like low operating cost, mass and volume reduction of food product thereby minimizing packaging, handling, storage and transport costs (Arumuganathan et al., 2010) [9] . Drying is a unit operation involving simultaneous mass and heat transfer thereby reducing water activity and consequential shelf life extension. However, drying induces a no. of changes in physical and chemical composition of foods like colour deterioration, enzymatic changes, degradation of antioxidant components. A number of drying methods can be employed for preservation of oyster mushroom like oven drying, sun, solar, microwave osmotic and freeze drying. Each of these drying methods has got their own advantages and limitations specific to them. The uncontrolled operating condition like temperature and relative humidity during sun and solar drying accelerate the physical and chemical changes occurring in foods. The high temperatures employed during oven and osmotic drying though reduce the drying times but at the same time degrade heat sensitive components like vitamin C and antioxidants. The microwave drying despite being faster induces physical and textural changes in food materials. The freeze drying method employs vacuum and low temperatures thereby retaining physical and chemical properties of food but high cost and longer drying times associated limit its application (Izli, 2017) [20] .