An insight into key volatile compounds in acerola (Malpighia emarginata DC.) pulp based on their odour activity values and chemometric evaluation

Abstract

The application of headspace solid-phase microextraction (HS-SPME) and dynamic headspace purge & trap (P&T) combined with gas chromatography-mass spectrometry and odor activity value was used to analyze volatile compounds from acerola (Malpighia emarginata DC.) pulp in order to determine their key aroma compounds. Chemometric evaluation led to the selection of the most efficient fiber of 50/30 μm divinylbenzene-carboxen-polydimethylsiloxane in capturing volatile compounds. Optimum conditions for HS-SPME were established and a total of 70 compounds were identified in pulp by HS-SPME, while 69 compounds were identified by P&T. The most represented class of compounds in HS-SPME was esters, while in P&T, it was alcohols. Among the large number of compounds identified, the most abundant were 4-pentenyl hexanoate, 4-pentenyl butanoate, hexyl butanoate and 1,4,4,7a-tetramethyl-2,4,5,6,7,7a-hexahydro-1H-indene-1,7-diol in the extract by HS-SPME while 3-methyl-3-buten-1-ol, ethanol, 1,4,4,7a-tetramethyl-2,4,5,6,7,7a-hexahydro-1H-indene-1,7-diol and 4-pentenyl butanoate were in P&T. Based on this study in association with the odor activity values, the key aroma compounds of acerola pulp were (Z)-β-ocimene, (E)-β-ocimene, methyl butanoate, linalool, (E)-β-ionone, (E)-2-hexenal, decanal, (E)-β-damascenone, methyl hexanoate, 3-methyl-3-buten-1-ol, heptanal, ethyl butanoate, ethyl hexanoate, 1-octen-3-ol and nonanal. These compounds are predominantly of fruity notes with the presence of sweet, herbaceous and fresh odors.