Effect of Boiling and Roasting Treatments on the Nutrients, Lipid Quality, and Flavor of Peanuts

Roasted peanuts (OPs) are more often used in daily life than boiled peanuts (BPs); the main reason may be related to the pleasurable flavor in OPs. This study comparatively investigated the effects of boiling and roasting on nutritional components contents, taste, and aroma to reveal the advantages of roasting in terms of the nutrition and flavor of peanuts. Results showed that boiling increased fat content to 54.47% of peanuts, diluted or reduced sugar content to an undetectable level, noticeably changed the contents of poly/monounsaturated fatty acids, and significantly decreased the content of free amino acid (FAA, 1.05 mg/g peanuts) in peanuts. Roasting simply decreased the contents of sugar and FAA to 2.78 and 1.82 mg/g peanuts, respectively. Compared with roasting, boiling had more discernible effects on fatty acids and FAAs. Both BPs and OPs have good dietary lipid quality. In terms of flavor, OPs had more FAAs (2 types) that contributed remarkably to the taste of peanuts than BPs (0 types), more volatile substances (40 types) than BPs (12 types), and a higher number of key volatile aroma components (8 types) than BPs (3 types). That is, roasting induced a relatively small effect on nutritional components and gave peanuts a richer taste and stronger aroma than boiling; therefore, roasting is an ideal peanut processing method. This study proved the different changes in peanuts caused by boiling and roasting on a material basis and corroborated the irreplaceability of roasting in peanut processing.