Retention of aroma compounds by carbohydrates: Influence of their physicochemical characteristics and of their physical state. A review

Many aroma compounds, used to flavor food products, are used in a solid state, after encapsulation. Carbohydrates are the most common matrices used to entrap these volatiles. It has been observed that depending on the aroma compound and the carrier, efficiency can vary. This article reviews the influence of physicochemical properties of both the volatiles and the carriers on retention. The latter depends on the functional groups of the aroma compound. Moreover, it increases with molecular weight and decreases with the polarity and relative volatility of the aroma compound. This behavior can be explained by the effect of these properties on the diffusion of the aroma compound through the matrix and on the ability of the volatile to form small drops. The physicochemical properties of the carrier are important too. Retention of the aroma compound increases with the molecular weight of the carrier until an optimum is reached and then decreases for very high polymerization degrees. Viscosity, solubility, and film forming properties improve the retention ability. The effect of these parameters is discussed according to their effect on the diffusion of the volatiles. The state of the carrier has to be taken into account too. The amorphous state provides the highest retention, collapse results in losses of aroma, and crystallization leads to the greatest losses of flavors.