Determination of Pyrazine and Flavor Variations in Peanut Genotypes During Roasting

Abstract

During peanut roasting, pyrazine compounds correlate highly with roasted flavor and aroma. Although roast color measurement is used to predict roasted flavor in peanuts, there are known variations between roast color and flavor development among genotypes. A method for measuring pyrazines using headspace solid-phase microextraction (SPME) was developed and 4 peanut genotypes were roasted and analyzed under a variety of time-temperature combinations. Peanut genotypes differed in roasted flavor and aroma, regardless of roast color. Florida MDR 98 formed the highest levels of pyrazines under the same roasting conditions, followed by Florunner, Georgia Greene, and SunOleic 97R, respectively. Of all pyrazines tested, 2,5-dimethylpyrazine was most highly correlated to roasted peanut flavor and aroma.

Multivariate relationships between instrumental attributes, microstructure, sensory profiles and consumer preference in roasted peanuts (Arachis spp)

“…1-methyl-1H-pyrrol (associated with sweet and woody odour) and 2,5-dimethylpyrazine (associated with sweet, malty odours) are two of the most reported aromatic components in roasted peanuts (Braddock, Sims, & O'Keffe, 1995;Ho et al, 1981;Ng, Dunford, & Chenault, 2008; and were also among the compounds detected at the highest concentrations in this study. In fact, some past researchers went further to suggest that 2,5-dimethylpyrazine is the compound with the single highest correlation with roasted peanut aroma, followed by 2,3,5-trimethylpyrazine and 2,3-dimethylpyrazine (Baker et al, 2003), which were also detected in this research, even though the flavour activity of 2,5-dimethylpyrazine has been since disproven ). 2-methylpyrazine, 2,6-dimethylpyrazine, 2,3,5-trimethylpyrazine, and ethylpyrazine often cited in peanut shelf life studies (Mei, Qi, Chang-sheng, Chang, & Feng-hong, 2011;Reed et al, 2002; can also be found in the same table.…”

“…Four sensory attributes, namely roasted peanut, sweet, dark roast and raw bean aromas were modelled with .70 respectively. The roasted peanut attribute had a poor R 2 coefficient, and the model should not be considered well-fitting, but the observations are nonetheless included here, as they are in good agreement with the literature (Baker et al, 2003;Braddock et al, 1995;Ho et al, 1981;Ho C.T. et al, 1983;Xiao et al, 2014).…”

“…Organoleptic differences between different grades of the same cultivar (Pattee, Isleib, Gorbet, & Geisbrecht, 2002), cultivars grown in the same region ), different genotypes (Baker et al, 2003) and different origins (Bett et al, 1994) when roasted by the same process to the same degree have all been previously reported. As part of the Uniform Peanut Performance Test (UPPT) the USDA, ARS, Market Quality and Handling Research Unit in Raleigh, NC, USA has been analysing and logging the sensory profiles of new peanut cultivars since 2001.…”

“…Several studies have tried to correlate volatile compound concentration to sensory response. Some were focused on quality defects (Reed, Sims, Gorbet, & O'Keefe, 2002; while others specifically on roasted peanut flavour (Baker et al, 2003;Da Conceicao Neta, 2010;, and two of these studies were also able to validate their findings with aroma reconstitution studies Da Conceicao Neta, 2010). The correlation between volatiles and sensory attributes is arguably of larger practical value than identifying character impact compounds.…”

“…Roasted peanut flavour has been mostly attributed to heterocyclic compounds, such as alkylpyrazines or more specifically to O-heterocyclic and Nheterocyclic compounds . In general, in older investigations pyrazines appeared to be the most important compounds produced during roasting in peanuts, (Baker et al, 2003;Ho, Lee, & Chang, 1981; Ho C.T., Jin Q.Z., Lee M.H., & Chang S.S., 1983) even though more recently this has been disproven using recombination studies Da Conceicao Neta, 2010).…”