Effects of roasting on phenolics composition and antioxidant activity of peanut (Arachis hypogaea L.) kernel flour

Abstract

The effects of roasting on the phenolics composition and antioxidant activity of peanut (Arachis hypogaea L.) kernel flour were appraised. Peanut kernel flour, with and without skin, were roasted at 160 °C for 10, 20, 30, 40 and 50 min. The resultant changes in the antioxidant activity of roasted peanut kernel flour were assessed by the determinations of total phenolics, 1,1-diphenyl-2-picrylhydrazyl free radical-scavenging capacity, percent inhibition of linoleic acid oxidation and thiobarbituric acid test and compared with those of unroasted kernel flour. It was observed that roasting significantly (p < 0.05) increased the antioxidant activity of the peanut kernel flour. HPLC analysis revealed the detection of three phenolic acids (phydroxybenzoic, chlorogenic, p-coumaric), two flavonols (quercetin, kaempferol), and a stilbene (resveratrol) both in the roasted and unroasted samples. In peanut kernel flour without skin, the contents of the phenolics increased in the initial roasting phase, however, decreased gradually in the later phase (>20 min of roasting time). In contrast, over the course of heating, the amounts of phenolics were noted to be slightly increased in the peanut kernel flour with skin; the most significant (p < 0.05) increase occurred in the concentration of pcoumaric acid and quercetin at 30, 40, and 50 min of roasting. The results of this study reveal that optimum roasting time should be sought to enhancing the antioxidant capacity and phenolics concentration in peanut kernel flour.

The e&#64256;ect of microwave roasting on the antioxidant properties of the Bangladeshi groundnut cultivar

“…The amounts of TPC in GME, GEE, GCE, and GMO signifi cantly (p < 0.05) increased from 1.96, 1.85, 1.17, and 0.91 mg GAE/g in an unroasted control to 3.41, 3.23, 2.01, and 1.64 mg GAE/g in 7.5 min roasted groundnut samples respectively. A similar trend was reported by Win et al (2011) for oven-roasted peanut extracts. Pandey and Awasthi (2015) also reported that roasting increased the total phenolic content in fenugreek seeds.…”

“…The changes in antioxidative activity and phenolic content, which occur during the conventional oven roasting (Craft et al, 2010;Davis et al, 2010;Win et al, 2011) of groundnuts (Arachis hypogaea L.) have been well investigated. To the best of our knowledge, nothing has been reported on the eff ect of microwave roasting on the antioxidative activity and phenolic content of the seeds of the groundnut cultivar developed in Bangladesh, which is the main objective of the present study.…”

The influence of microwave cooking on the nutritional composition and antioxidant activity of the underutilized perah seed

“…After 3 min MW cooking, the samples showed a TPC of 4.52 mg TAE/g or more: PMW (8.94 mg TAE/g) > PEW (7.54 mg TAE/g) > PME (6.42 mg TAE/g) > PEE (5.70 mg TAE/g) > PMO (4.52 mg TAE/g). A similar trend was found by Ali et al (2016a) for microwaved groundnut, and by Win et al (2011) for oven-roasted peanut. The roasting process most likely increased the TPC through the following mechanisms: roasting might partially destroy the cell structure, resulting in the release of some bound phenolic compounds, which could then become more extractable in aqueous ethanol and acetone (Zou et al, 2015).…”

Nutraceutical enriched Indian traditional chikki

“…It has been revealed that the optimum roasting time was essential for enhancing the antioxidant capacity and phenolics concentration in peanut kernel flour Win et al (2011).…”