Aroma profiling of forward-osmosis watermelon juice concentrate and comparison to fresh fruit and thermal concentrate

Abstract

This work reports the sensory evaluation of the aroma of a forward osmosis (FO) concentrate of watermelon (Citrullus lanatus) juice. The FO concentrate's overall aroma liking and individual aroma attributes were compared to those of fresh-cut watermelon and a conventional thermally-evaporated concentrate prepared from the same source juice (“thermal concentrate”). For the aroma rating, a structured 15-point hedonic scale was used, and for aroma profiling a check-all-that-apply (CATA) approach was taken. The thermal concentrate was found to have degraded aroma quality. In contrast, FO concentrate had a highly-liked aroma, and it outperformed the thermal concentrate in the hedonic rating. There was no significant difference (p < 0.05) in the hedonic rating between the aromas of the FO concentrate and fresh watermelon. Multiple Correspondence Analysis (MCA) of aroma attributes indicated that the off-odors “Fishy” and “Mushroom” were most associated with the thermal concentrate, while characteristic “Watermelon” aroma was most associated with the FO concentrate (even moreso than it was with fresh-cut watermelon). Since the sensory panel size (N = 41) was somewhat small, these results should be confirmed with a larger population, but they are nevertheless supportive of further development of FO for concentration of watermelon juice.