| heal.abstract |
The impact of incorporating ground dry-blanched or roasted peanut skins (PS, three types: light-, medium- and dark-roasted) into peanut butter as a functional food ingredient was examined. A desirable grind size for the PS of less than 300 μm was achieved in most cases by milling the skins with the sugar. Adding ground PS to peanut butter at 1.25, 2.5, 3.75 and 5.0% (w/w) resulted in a concentration-dependent change in the Commission Internationale de l'Éclairage L* C* h values. Peanut butters formulated with medium- and dark-roasted PS showed an increase in hardness, and were generally more adhesive than those without PS or with dry-blanched PS. A marked change in spreadability was found with greater than 2.5% added PS. Incorporation of dry-blanched PS, especially at levels below 3.75%, produced the fewest alterations in physical properties of the peanut butters compared with the control. Importantly, a concentration-dependent increase in the total phenolics content (TPC) was evident with PS fortification. Dry-blanched PS had a TPC of ∼166 mg (+)-catechin equivalents/g extract and yielded peanut butters with a 32, 33 and 38% higher TPC than found with light-, medium- and dark-roasted skin incorporation, respectively. Correspondingly, dry-blanched PS addition at 1.25, 2.5, 3.75 and 5.0% (w/w) resulted in an increase in the TPC by 86, 357, 533 and 714%, respectively, compared with peanut butters without PS fortification. © 2012 Wiley Periodicals, Inc. |
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