Flavour Binding by Solid and Liquid Emulsion Droplets - Food Colloids: Self-Assembly and Material Science - page 423

Chapter 29

Flavour Binding by Solid and Liquid
Emulsion Droplets

Supratim Ghosh, Devin G. Peterson and John N. Coupland

DEPARTMENT OF FOOD SCIENCE, PENNSYLVANIA STATE
UNIVERSITY, PA 16802, USA

29.1 Introduction
The concentration of volatile molecules in the head-space is among the most
important parameters determining the sensory qualities of a food. The per-
ceived aroma depends on the total concentration of volatiles in the product,
and also on the extent to which they are bound by the food. For a system at
equilibrium, the distribution of a given volatile between the food and the head-
space gas is given by its partition coefficient,
K ge ¼ c g

ð 1 Þ

c e ;

where c g and c e are concentrations of volatile compounds in the head-space and
in the food, respectively. (Formally this should be written in terms of activity,
but as concentrations of volatiles are typically very low the difference is
negligible.) In a multiphase food, the volatiles will distribute themselves
between all of the available phases according to the relevant partition coe-
cients, and these can be combined into an effective partition coefficient for the
food. For example, in a food emulsion, the effective partition coefficient K ge is
related to the volume fraction of oil ( f o ) and the gas oil and gas water
partition coefficients, K go and K gw , respectively:

1
K ge

¼ f o
K go

þ ð 1 f o Þ
K gw

: ð 2 Þ

Equation (2) has proved useful in modelling the effects of changing liquid oil
concentration on the head-space concentration of volatiles above an emul-
sion. 1-3 Nevertheless, the interaction with solid fats is less clear, with some
workers arguing 4,5 that solid fat does not interact with volatile molecules, while
others suggest 5,6

that there may be some binding of the aroma compounds to

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