Volatile Composition and Aroma Activity of Guava Puree Before and After Thermal and Dense Phase Carbon Dioxide Treatments

Abstract

Volatiles from initially frozen, dense phase carbon dioxide (DPCD)- and thermally treated guava purees were isolated by solid phase microextraction (SPME), chromatographically separated and identified using a combination of gas chromatography-mass spectrometry (GC-MS), GC-olfactometry (GC-O), and GC-pulsed flame photometric detector (GC-PFPD, sulfur mode). Fifty-eight volatiles were identified using GC-MS consisting of: 6 aldehydes, 2 acids, 15 alcohols, 6 ketones, 21 esters, and 8 terpenes. Eleven volatiles were newly identified in guava puree. Hexanal was the most abundant volatile in all 3 types of guava puree. Ten sulfur compounds were identified using GC-PFPD of which 3 possessed aroma activity and 3 were not previously reported in guava puree. Both treatments profoundly reduced total sulfur peak areas and produced different peak patterns compared to control. Thermal treatment reduced total sulfur peak area 47.9% compared to a loss of 34.7% with DPCD treatment. Twenty-six volatiles possessed aroma activity. (Z)-3-Hexenyl hexanoate was the major contributor to the aroma of the freshly thawed and DPCD-treated guava puree. DPCD treatment reduced total MS ion chromatogram (MS TIC) peak area 35% but produced a GC-O aroma profile very similar to control. Whereas thermal treatment reduced total TIC peak area only 8.7% compared to control but produced a 35% loss in total GC-O peak intensities.

Quality Changes of Orange Juice after DPCD Treatment

“…Most previous studies only reported the reduction of volatile compounds after DPCD [3][4][5]; in this work, increases of some volatile compounds were detected, and the increase of the volatile components was found to be due to the decreasing changes of particles. In addition, the high correlations of the volatile components and color parameters might reflect that the volatile components and pigments changed simultaneously in the juice system.…”

“…Gasperi et al [4] reported that the contents of esters and aldehydes in fresh apple juice were reduced by more than half after DPCD treatment. Plaza et al [5] reported that DPCD treatment reduced the total MS ion chromatogram peak area by 35% in guava purée. It is possible that the volatile components were removed by CO 2 during depressurization.…”

Structure–Odor Activity Studies on Monoterpenoid Mercaptans Synthesized by Changing the Structural Motifs of the Key Food Odorant 1-p-Menthene-8-thiol

“…The grapefruit-like-smelling 1- p -menthene-8-thiol, which is one of the most potent food odorants ever reported, was first detected in grapefruit juice . Later it was also identified in orange juice, grape must, wine, and guava puree . The second naturally occurring mercapto monoterpenoid, 8-mercapto- p -menthan-3-one, exhibits a characteristic catty, black currant-like odor and is only known as a constituent of the oil from the leaves of the South African buchu bush .…”

Spotlight on release mechanisms of volatile thiols in beverages

“…Sixteen years later, Mahattanatawee et al and Clery et al identified three important thiols: 3MH, 3MHA and 4MMPOH, using headspace and solvent extraction techniques (Clery & Hammond, 2007;Mahattanatawee, Goodner, & Baldwin, 2005). More recently, three other thiols were identified (4MMP) or confirmed (1-p-menthene-8-thiol and 2MFT) in guava puree using GC-pulsed flame photometric detector (GC-PFPD, sulfur mode) (Plaza, Marshall, & Rouseff, 2015).…”