Characterization of the Volatile Compounds in Raw and Roasted Georgia Pecans by HS‐SPME‐GC‐MS

Abstract

Volatile compounds are responsible for the characteristic aroma of raw and roasted pecans. Yet, much is unknown about the specific effects of roasting on pecan volatiles. In this study, the volatiles of raw “Desirable” pecans from Georgia and 3 roasted pecan samples (175 °C for 5, 10, and 15 min) were determined by HS‐SPME coupled to GC‐MS using stable deuterium‐labeled volatiles as internal standards for quantitation. As expected, roasting markedly impacted the volatile profile of pecans: a total of 63 flavor‐active compounds were identified in roasted samples, including 9 compounds not detected in raw “Desirable” pecans. Pyrazines, notable indicators of the Maillard reaction, were found only in roasted samples and demonstrated continual increases throughout observed roasting times. Furthermore, it was noted that hydrocarbon derivatives showed substantial increases with roasting, likely a result of the degradation of nonvolatile lipids. The observed changes correspond well to prior sensory investigations concerning the impact of roasting on pecan flavor, and explain increases in intensity for roasted, nutty, buttery, and sweet sensory traits. Practical Application The results of this study document the volatile constituents generated during the roasting of pecans, and this may help formulators, who are trying to develop natural and artificial pecan flavors in new food products.

Investigation of sugars, organic acids, phenolic compounds, antioxidant activity and the aroma fingerprint of small white apricots grown in Xinjiang

“…Among these fruits, forty apricots were kept at 4 °C until required, and other apricots were sliced, frozen in liquid nitrogen and stored at −80 °C for subsequent analysis. In the study, three replicates were performed for all chemical analyses (Gong, Kerrihard, & Pegg, 2018).…”

“…Helium was used as the carrier gas at a rate of 1.0 mL/min. The GC oven temperature was held at 40 °C for 2 min, 40 to 180 °C at 3 °C/min, 180 °C for 3 min, 180 to 230 °C at 10 °C/min, and 230 °C for 5 min (Gong et al., 2018). Electron impact mass spectra were acquired at 70 eV with an ionization source temperature of 270 °C.…”

“…The retention index (RI) of the compound was calculated based on an alkane series (C 5 –C 24 ) (Sigma), which had the same GC‐MS analytical procedure as the samples. Quantitative analysis was carried out using the internal standard method as described by (Gong et al., 2018). The concentrations of volatile components were expressed as µg/kg.…”

Quantitative Analysis of Pyrazines and Their Perceptual Interactions in Soy Sauce Aroma Type Baijiu

“…Pyrazines are six-membered heterocyclic compounds with two nitrogen atoms at positions 1 and 4 [14]. Pyrazines are responsible for universally desirable and enjoyable aromas and have been identified in many foods and beverages, particularly as significant volatile components of various nuts, such as peanuts [15], almonds [16], hazelnuts [17] and pecans [18]. While the significance of a variety of pyrazines affecting roasted and nutty aromas has already been highlighted, existing studies have not explored potential perceptual interactions.…”

Genetic characterization of an almond germplasm collection and volatilome profiling of raw and roasted kernels

“…Other relevant VOC mass peaks that significantly increased during roasting were methanol (m/z 33,033), cyanamide (m/z 43.03), acetic acid (m/z 61.028), 1-hydroxy-2-propanone (m/z 75.044), and γ-Butyrolactone (m/z 87,0453) (Table 1). Many of these compounds were found in roasted almonds and other nuts such as hazelnuts 41 , walnuts 42 , pecans 43 , peanuts 44 . Some similarities were also found with the aroma compound formation during coffee roasting which is well studied both by GC-MS and PTR-MS.…”