Physicochemical, Microbiological and Sensory Evaluation of Freeze-Dried Eggs Stored after Irradiation

N. KALOYANOV1, S. BAKALIVANOV2, T. BAKALIVANOVA2 and S. GRIGOROVA2
1 University of Chemical Technology and Metallurgy, BG - 1756 Sofia, Bulgaria
2 Institute of Cryobiology and Food Technologies, BG - 1407 Sofia, Bulgaria

Abstract

KALOYANOV, N., S. BAKALIVANOV, T. BAKALIVANOVA and S. GRIGOROVA, 2008. Physicochemical, microbiological and sensory evaluation of freeze-dried eggs stored after irradiation. Bulg. J. Agric. Sci., 14: 22-27

An experiment with freeze-dried whole hen’s egg has been carried out to study the efficacy of the combination of two methods used for the preservation of foodstuffs - freeze-drying and irradiation with optimal dose of gamma rays, in order to prolong its shelf-life as well as to guarantee its microbiological safety. The physicochemical, microbiological and organoleptic characteristics of the freeze-dried egg mélange were determined. During the 4-year period of storage at room temperature of the freeze-dried (control group) and the freeze-dried and irradiated with a dose up to 3.5 kGy melange no significant changes were found into the sensory characteristics till the 28th month, while the physicochemical ones stayed unaltered. The quantity of thiobarbituric acid reactive substances (TBARS, meaning milligrams malondialdehyde equivalent per kilogram) in the irradiated samples was in parallel increase with the dose till the 6th month of the time of storage, while after that it was decreasing. The microbiological features of the irradiated freeze-dried eggs have been improved during storage. The mathematical processing of the data showed that the time of storage (FA) was the main factor for the slight changes established, while gamma irradiation had no essential influence.

Key words: freeze-dried egg melange, gamma-rays treatment, storage, thiobarbituric acid reactive substances (TBARS), sensory evaluation, physicochemical characteristics Introduction

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