The effect of low temperature on hens' eggs

Abstract

Colloids when frozen do not as a rule recover their original state on thawing. Stiles quotes many such cases, a well-known example being a gel of silicic acid which is separated by freezing and thawing into a mixture of water and solid flakes of acid. Similarly, when a solution of chlorophyll in water is frozen slowly, the chlorophyll on thawing is found to be aggregated into large flocks which slowly settle to the bottom. Recovery of state, however, takes place in certain systems, not necessarily the simplest, if the rate of freezing be high enough. The solution of chlorophyll furnishes an example. If it be frozen in liquid air it completely recovers its original state on thawing. Obviously the end temperature does not matter because it may be said with certainty that the frozen mass could be kept at the temperature of liquid air indefinitely without losing the capacity of reforming a solution on thawing. There must therefore exist a certain limited range of temperature within which alone the process of desolution can occur. Let us call this the critical range. The peculiar feature of any temperature within the critical range θ 1 - θ 2 is that, if the system be kept at that temperature for a critical length T of time, changes take place which are not reversed on thawing.

Determination of the Gelation Mechanism of Freeze–Thawed Hen Egg Yolk

“…Thus, the diameter of the majority of yolk particles decreased in 168 d and increased in all other gelled yolk samples compared to CF and C0d. This trend was seen in the surface area and volume moment mean (D [3,2] and D [4,3], respectively) of the aforementioned sample groupings ( Figure 3.4). The volume moment mean was especially important because it reflects the size of particles that constitute the majority of the sample volume.…”

“…The surface area moment mean must not be neglected, as it was important to monitor the proportion of smaller particles (i.e., unaggregated LDL) present. [3,2], and D [4,3] were observed in CF, C0d, and 1d samples (p < 0.05) ( Figure 3.4, Appendix B2). As fresh yolk transitioned to zero storage gelled yolk and then 1 d gelled yolk, the particle size distribution shifted significantly towards particles with larger diameters.…”

“…As surface area and volume moment mean increased from 1 to 84 d, yield stress increased. Based on this relationship, D [3,2] and D [4,3] of 168 d was expected to increase significantly from 84 d.…”

“…Two controls, fresh (CF) and 0 d gelled yolk (C0d), and seven treatments (1, 3, 7, 14, 28, 84, 168 d) were measured in triplicate using a Malvern Brouckere Mean Diameter, D [4,3], were also reported. The surface area moment mean is relevant where specific surface area is important and is most sensitive to fine particulates.…”

“…In this study, fresh and gelled yolk (stored at -20°C for 0, 1,3,7,14,28,84, and 168 d and thawed) were examined to determine the effect of varying frozen storage times on yolk gelation. Our preliminary results indicated that frozen storage time had an effect on gelation.…”