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 soli d state, after encapsulation. Carbohydrates are the most common matric es used to entrap these volatiles. It has been observed that depending on the aroma compound and the carrier, efficiency can vary. This arti cle reviews the influence of physicochemical properties of both the vo latiles and the carriers on retention. The latter depends on the funct ional groups of the aroma compound. Moreover, it increases with molecu lar weight and decreases with the polarity and relative volatility of the aroma compound. This behavior can be explained by the effect of th ese properties on the diffusion of the aroma compound through the matr ix and on the ability of the volatile to form small drops. The physico chemical properties of the carrier are important too. Retention of the aroma compound increases with the molecular weight of the carrier unt il an optimum is reached and then decreases for very high polymerizati on degrees. Viscosity, solubility, and film forming properties improve the retention ability. The effect of these parameters is discussed ac cording to their effect on the diffusion of the volatiles. The state o f the carrier has to be taken into account too. The amorphous state pr ovides the highest retention, collapse results in losses of aroma, and crystallization leads to the greatest losses of flavors.