It is now well documented that the diet has a significant impact on human health and well-being. However, the complete set of small molecule metabolites present in foods that make up the human diet and the role of food production systems in altering this food metabolome are still largely unknown. Metabolomic platforms that rely on nuclear magnetic resonance (NMR) and mass spectrometry (MS) analytical technologies are being employed to study the impact of agricultural practices, processing, and storage on the global chemical composition of food; to identify novel bioactive compounds; and for authentication and region-of-origin classifications. This review provides an overview of the current terminology, analytical methods, and compounds associated with metabolomic studies, and provides insight into the application of metabolomics to generate new knowledge that enables us to produce, preserve, and distribute high-quality foods for health promotion.

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A consistent, pure supply of high-oleic (HO) peanuts is important to certain segments of the food industry as it allows for the production of confections and other products with improved shelf-life characteristics. Peanut shellers have struggled with food industry demands for lots which contain greater than 95% high-oleic peanuts. Normal-oleic (NO) and HO cultivars of virginia and runner market type peanuts were grown during the 2012 and 2013 growing season respectively to investigate differences in fatty acid development between HO and NO peanuts. Fatty acid profiles of individual seeds from individual plants taken across the growing season were determined in relation to seed fresh weight. Fatty acid profiles of HO virginia-type seeds from the early sampling date of 78 days after planting (DAP) revealed oleic acid to linoleic acid ratios (O/L) of only 4.0 in the seeds of the greatest fresh weight. As the oleic acid concentration in many of the HO virginia-type peanuts reached 60 to 80% and the linoleic acid concentrations ranged from less than 1.0 to 10 % by the middle sampling date (106 DAP), the O/L ratios of most HO seeds were well above the industry accepted cut-off ratio of 9.0. A similar change in the fatty acids was seen in the HO runner cultivar. Increases in oleic acid and decreases in linoleic acid contents occurred in conjunction with the increased seed fresh weights. The data indicate that HO seed attain high-oleic status as physiological development progresses as seen in the changing seed fresh weight. However at the final sampling dates which corresponded to the harvest dates, O/L ratios of less than 9.0 were still present for the HO cultivars of both market types despite the fresh weight of some seeds being of potential marketable size. It was concluded that some of the perceived contamination of HO seed lots with NO seed could be the result of normal peanut development, especially in the virginia-type cultivar with the larger sized seeds.

In recent years, there has been increased interest in antioxidant-rich products by consumers wanting to enhance the health benefits of their diet. Chocolate has been identified as a natural source of antioxidant compounds, which resulted in the development of polyphenol-enriched chocolate products that are now available commercially. This study investigated the use of phenolic compounds extracted from peanut skins as a novel antioxidant source for the enrichment of milk chocolate. The extracts were encapsulated with maltodextrin to lessen their bitterness. Antioxidant potential of the encapsulated peanut skin extracts was evaluated by the 2,2-diphenyl-1-picrylhydrazl radical quenching assay. Encapsulated peanut skins were found to have a corrected Trolox equivalency of 31.1 μmol/g of chocolate up to 0.8% (w/w). To produce a product with an antioxidant content similar to that of dark chocolate yet which maintained the milder flavor of milk chocolate, the best estimate threshold of encapsulated peanut skin extract in chocolate was 0.9 % (w/w) based on the standard method (American Society of Testing Materials; ASTM E-679). Consumer liking of milk chocolate enhanced by adding subthreshold (0.8 % (w/w)) inclusion levels of encapsulated peanut skin extract was found to be at parity with milk chocolate as a control.

Peanuts (Arachis hypogaea L.) are prized for their flavor and popular worldwide as food or as food ingredients. The raw peanut seed contains the precursor compounds to roasted peanut flavor and has the potential to be manipulated through traditional breeding methods. However, little is known about the metabolome of the raw seeds. Comprehensive metabolite profiles of both raw runner and Virginia‐type peanuts were determined. Using a system incorporating several methodologies including (RP)/UPLC‐MS/MS and HILIC/UPLC‐MS/MS, along with quantitation of fatty acids, free amino acids, and tocopherols, 365 metabolites were identified and of these, 52 were significantly different between market types (P < 0.05). Higher levels of gamma‐glutamylalanine, oxylipins, purine metabolites, and alpha‐ketoglutarate derived members of the glutamate family of amino acids defined the Virginia‐type, while runner‐type peanuts were differentiated by their ethylmalonate and eicosenoate content. This study presents a comprehensive analysis of the raw peanut seed, providing knowledge of the range of small molecules present in peanuts. The new information presented here will enable future research for peanut quality improvement. Practical Application Peanuts are widely used as snack foods and as food ingredients. Knowledge of the secondary metabolite compounds in raw peanuts is needed to determine their importance in peanut flavor and nutritional quality. This report used a nontargeted analytical approach for the identification of these types of compounds in peanuts for the first time. These data were supplemented with quantitative analysis of free amino acids and tocopherols and discussed as potential flavor precursors and health promoting compounds.