Effect of sugars on liquid–vapour partition of volatile compounds in ready‐to‐drink coffee beverages

Abstract

The effect of sugars (sucrose, lactose, glucose, fructose, 10%w/v) on the liquid-vapour partition of selected volatile compounds of coffee beverages has been investigated in espresso coffee and ready-to-drink (RTD) canned coffee prepared and obtained by using the same Arabica roasted coffee beans blend. Aroma composition of coffee beverages has been preliminary investigated by headspace-gas chromatography (HS-GC) and solid phase microextraction-HS-GC-mass spectrometry to characterize the volatile pattern of the systems and to evaluate the effects of sugars on the aroma release/retention. Then, the liquid-vapour partition coefficient (k) of 4 selected key aroma compounds (diacetyl, 2,3-pentanedione, ethylpyrazine, hexanal) was determined in water, sugars solutions as well as RTD coffee brews added with the same sugars (10%w/v). Sugars added in coffee beverages affected the release of the volatiles and thus its aroma profile with differences due to the type of added sugar and coffee brew type. The k values of the selected volatile compounds resulted different depending on the model system composition (water, coffee brew) and sugar type added. In particular, melanoidins as well as other non-volatile components (lipids, acids, carbohydrates) in the RTD coffee brews could be implied in the change of k of the volatile compounds in respect to that observed in water. The effects of the sugar type on the release/retention of the four key coffee aroma compounds were partly explained in terms of 'salting out' especially for the more polar volatile compounds and in the sucrose-added model systems. The change of chemical and physico-chemical properties of the water and brews induced by the sugars as well as the occurrence of interactions between volatile compounds and non-volatile components may be implied in the reduction of the vapour partition of the aroma compounds.

Influence of Cryoconcentration on Quality Attributes of Apple Juice (Malus Domestica cv. Red Fuji)

“…The increase in volatile components could be due to the high concentration of each component (reflected in TSSC) cycle-by-cycle, which can be detected by the chromatograph. This effect is consistent with observed by Piccone et al [46] in coffee beverages, indicating that the concentration of sugars (such as sucrose, glucose, and fructose) positively affects the release of volatiles in the headspace. The volatile compounds concentrated by BCC are showed in the chromatograms.…”

Effect of hydrocolloids, sugar, and citric acid on strawberry volatiles in a gummy candy

“…The addition of sugar (polar cosolute) to the solution can modify the solubility of the volatile compound by favoring “salting‐in.” There is a change in the structure of the water around the less polar substance due to a change in the water solvency and/or by creating an intramolecular nonpolar environment for hydrophobic molecules to react with each other (solute interaction) (Chiou et al, ). The concentration of four selected aroma compounds significantly decreased when the sugar was increased from 0 to 10% wt/vol in a model system (Piccone, Lonzarich, Navarini, Fusella, & Pittia, ).…”

Interaction of aroma compounds with food matrices

“…The influence of the addition of sugars on aroma release depends both on the aroma compound and the type of sugar studied. Glucose and sucrose present similar effects whereas lactose induces a greater increase in the release of aroma compounds (Piccone et al, 2012). By modelling aroma release as a function of sucrose concentration, Nahon et al (2000) observed that at low sucrose concentrations the partition coefficient primarily controls the flavour release, whereas at higher sucrose concentrations the mass transfer coefficient has more influence on their concentration.…”