foam-mat freeze drying of egg white and ... - McGill University

IV. OPTIMIZATION OF EGG WHITE FOAM STABILITY FOR
4.1 Abstract
FOAM-MAT FREEZE DRYING
Egg white (albumen) is a rich source of protein and is widely used in
confectionary industry for its wonderful foaming ability. Foam-mat freeze drying is one
of the promising methods of drying, which tries to utilize the advantages of both freeze
drying and foam-mat drying to produce better quality egg white powder. Preliminary
experiments showed that the stability of foams made with egg white alone is not
adequate for foam-mat freeze drying. Experiments were thus conducted using different
stabilizers (Methyl cellulose, Propylene glycol alginate and Xanthan gum) to optimize
foam stability. Bubble size distribution was determined using microscopy technique to
understand foam structure. This paper will discuss about the effect of stabilizers on the
stability of egg white foam and possible mechanisms involved. The results showed that
Xanthan gum at 0.125% provide sufficient stability for freeze drying.
4.2 Introduction
Egg white or egg albumen is widely used in food processing industries especially
in bakery industry due to its ability to form higher volume and to produce relatively
stable foam. One of the advantages of using egg white in bakery industry is that it
improves the ability of the product to trap the air inside, which gives the characteristic
spongy texture of the product (Alleoni & Antunes 2004; Foegeding et al. 2006). The egg
white foam is an important ingredient in the preparation of many bakery foods such as
breads, cakes, meringues, soufflés etc.
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