Effect of grinding and extraction conditions on the determination of antioxidant activity and phenolic acids in barley

Comprehensive Characterization of Global Barley (Hordeum vulgare L.) Collection Using Agronomic Traits, β-Glucan Level, Phenolic Content, and Antioxidant Activities

This study characterized the diversity of 367 barley collections from 27 different countries, including 5 control cultivars, using several phenotypic traits. Morphological traits, including spike type, grain morphology, cold damage, and lodging rate, exhibited wide variations. Eighteen accessions matured early, while four accessions had longer culm and spike lengths than the controls. The ranges of total phenolic content (TPC), β-glucan content, ABTS•+ scavenging activity, DPPH• scavenging activity, and reducing power (RP) were 1.79-6.79 mg GAE/g, 0.14-8.41 g/100 g, 3.07-13.54 mg AAE/100 g, 1.56-6.24 mg AAE/g, and 1.31-7.86 mg AAE/g, respectively. Betaone, one of the controls, had the highest β-glucan content. Two accessions had β-glucan levels close to Betaone. Furthermore, 20 accessions exhibited increased TPC compared to the controls, while 5 accessions displayed elevated ABTS•+ scavenging activity. Among these, one accession also exhibited higher DPPH• scavenging activity and RP simultaneously. Based on the statistical analysis of variance, all the quantitative traits were significantly affected by the difference in origin (p < 0.05). On the other hand, grain morphology significantly affected biochemical traits. Multivariate analysis classified barley accessions into eight groups, demonstrating variations in quantitative traits. There were noteworthy correlations between biochemical and agronomical traits. Overall, this study characterized several barley varieties of different origins, anticipating future genomic research. The barley accessions with superior performances could be valuable alternatives in breeding.

Optimization of the Extraction Conditions of Antioxidant Phenolic Compounds from Strawberry Fruits (Fragaria x ananassa Duch.) Using Response Surface Methodology

The subject of this study is to determine the best solvent and optimum extraction conditions for the extraction of maximum antioxidant phenolic compounds and antioxidant activity from strawberry fruits (Fragaria x ananassa Duch.). Extractions were carried out using solvents with different polarities (water, methanol, ethanol, acetonitrile, and acetone). Box-Behnken Design was used to optimize extraction conditions, including extraction time (t), temperature (°C), and liquid/solid (L/S) ratio. In the study, extracts obtained with acetone indicated the highest total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity. The optimal extraction conditions for both responses were determined to be time of 17.5 min, temperature 52.5 °C, and liquid/solid ratio of 30:1. The maximum TPC and TFC values were found as 18.78 ± 0.22 mg of gallic acid equivalent (GAE/g) and 10.52 ± 0.35 mg of catechin equivalents (CE/g) under optimum extraction conditions. The results indicated that optimizing extraction conditions is critical for quantifying antioxidant phenolic compounds. The present model can contribute to finding a cheap way of delivering natural antioxidants in the food, cosmeceutical, and pharmaceutical industries. Furthermore, these results indicate that strawberry fruits (Fragaria x ananassa Duch.) can be a natural food colorant in dietary applications with potential health benefits.