_____________________________________________________________________________________________________ *Corresponding author: E-mail: brahmini.charan@gmail.com; Current Journal of Applied Science and Technology 40(9): 70-79, 2021; Article no.CJAST.68536 ISSN: 2457-1024 (Past name: British Journal of Applied Science & Technology, Past ISSN: 2231-0843, NLM ID: 101664541) Physico-Chemical and Microbial Properties of Stored Mushroom Slices B. Brahmini 1* , L. Edukondalu 1 , Venkata S. P. Bitra 1 and G. Veeraprasad 2 1 Department of Processing and Food Engineering, College of Agricultural Engineering, Bapatla, Guntur District, Andhra Pradesh, 522101, India. 2 College of Agricultural Engineering, Bapatla, Guntur District, Andhra Pradesh, 522101, India. Authors’ contributions This work was carried out in collaboration among all authors. Author BB designed the study, wrote the protocol, collected data, performed the statistical analysis, managed the literature searches, wrote the first draft of the manuscript and managed the field investigation. Authors LE and VSPB read, corrected and approved the final manuscript. Author GV supported financially this study. All authors read and approved the final manuscript. Article Information DOI: 10.9734/CJAST/2021/v40i931349 Editor(s): (1) Dr. Alessandro Buccolieri, Università del Salento, Italy. Reviewers: (1) Maria Erna Kustyawati, University of Lampung, Indonesia. (2) Soroush Soltani, Universiti Putra Malaysia, Malaysia. Complete Peer review History: http://sdiarticle4.com/review-history/68536 Received 06 March 2021 Accepted 11 May 2021 Published 12 May 2021 ABSTRACT Button mushroom (Agaricus bisporus L.) is extensively produced and consumed in the world. They are more perishable due to their high moisture content. Due to its short shelf-life, the mushroom is usually dehydrated for preservation. Hot air dried mushrooms result in losses in nutrients, colour degradation and deformation in structure. To overcome these problems, freeze-drying of mushroom slices was investigated. White button mushrooms after cleaning were vertically cut into 2, 4, 6 and 8 mm thick slices. Sliced mushrooms were frozen at −20 °C and then subjected to the freeze-drying at various heating plate temperatures of 10, 20, 30 and 40 °C. The effect of slice thickness and heating plate temperature on physicochemical properties like rehydration, porosity, firmness, water activity, colour, ascorbic acid, protein and microbial properties like total bacterial, yeast and mould were evaluated during the storage. Increase in the storage period resulted in decrease in porosity (73.25%), colour L* value (48.12), firmness (0.98 N), rehydration ratio (4.04), ascorbic acid content (14.47 mg/100 g) and protein content (19.15%), whereas the water activity (0.412) increased with the storage period. This may be due to the absorption of moisture during storage. Microbial analysis indicated by yeast count, mould count and total plate count was nil during the first three weeks of storage, whereas in the fourth week negligible growth was observed. So it is concluded that this may be due to the low water activity of stored mushroom slices. Original Research Article