Major volatile compounds produced by deterioration in frozen peanut kernels

OLMEDO RUBÉN O.; LARRAURI MARIANA; GAYOL M. FERNANDA; GROSSO NELSON R.

Chicago, Illinois

Congreso; IFT 2015 Annual meeting and food expo; 2015

IFT Institute of Food Technologist

Consumers look for peanuts because of their nice flavor. Roasted peanut flavor is related to some molecules like alquil-pyrazinas. Frozen kernels is a defect that appears in peanut lots when are harvested at low temperature. These frozen kernels produce off-flavors in derived peanut products. The objective of this study was to evaluate the volatile compounds in peanuts butter prepared with frozen kernels in comparison with peanut butter prepared with normal kernels. Two different peanut butter were prepared using blanched peanuts: (1) normal peanut butter with 0% frozen kernels (NPB) and (2) peanut butter with 30% frozen kernels (FPB). The volatile compounds from peanut butter samples were captured by SPME fiber PDMS/DVB and analyzed by GC-MS. The amount of volatiles was expressed as relative percentage. ANOVA and LSD test were carried out on the data. FPB shower lower amount of compounds like pyrazines that are related to typical roasted peanut flavor. The relative percentages of 2,5-dimethylpyrazine, 2-ethyl,5-methylpyrazine, and methylpyrazine were 2.13% in FPB and 8.7% in NPB, 0% in FPB and 1.9% in NPB, and 0.11% in FPB and 1.10% in NPB, respectively. Only FDP exhibited compounds related to lipid deterioration like pentanal (2.06%), hexanal (22.81%), 2-heptenal (1.36%), 2-nonenal (15.90%), and nonanal (2.19%) were found. Also, only FPB showed compounds derived from amino acid decomposition like hexylmethylamine (1.09%), N-methyltyramine (4.04%), and N- acetyltyramine (0.67%). Frozen process occurs during harvest at low temperatures and produces cell breakdown releasing its content that is exposed to different biological reactions. Frozen peanut kernels show molecules related to lipid and amino acid deterioration reactions. The preparation of peanut butter using peanuts with frozen kernel could affect significantly the flavor of the final product.