Antioxidant Activity of Fractions From Acid Hydrolysates of Almond Shells

Abstract

Acid hydrolysis of almond shells was carried out with 2.5 and 5% sulfuric acid, and the ethyl acetate soluble fraction of hydrolysates (EASH) was fractionated on a Sephadex Uppsala, Sweden) column. Three fractions were recovered from the crude extract produced by hydrolysis with 2.5% sulfuric acid (EASH-2.5), and five from the one produced with 5% sulfuric acid . The recovered fractions were assayed for phenolic content, radical-scavenging activity (measured by the a,a-diphenylb-picrylhydrazyl and Trolox equivalent antioxidant capacity [TEAC] methods) and reducing capacity (measured by the ferric-reducing antioxidant power [FRAP] and the reducing power methods). The highest contents of phenolics corresponded to the third fraction (F3) from EASH-2.5 and to the fourth fraction (FЈ4) from EASH-5, whereas fraction 1 (F1) from EASH-2.5 and fraction 4 from EASH-5 showed the highest TEAC and FRAP values, and reducing power. PRACTICAL APPLICATIONSAcid-catalyzed hydrolysis for producing xylose is the most common technology for processing almond shells into chemicals, and allows fractionation of this residue into a solid fraction (cellulose and lignin) and a liquid stream containing monomeric sugars, sugar degradation products, extractives and lignin depolymerization compounds. To destine the monomeric sugars as a carbon source for bioconversion purposes, a detoxification step is required. Solvent extraction with ethyl acetate yields a by-product fraction consisting of compounds with phenolic nature and antioxidant activity, and its utilization 1 Corresponding

Antioxidant property of solvent extract and acid/alkali hydrolysates from rice hulls

“…In agreement to our work, some previous research reports indicate the use of acid/alkaline hydrolysis to recover polyphenols from different plant materials such as Brewer spent grains (Moreira, Morais, Barros, Delerue-Matos, & Guido, 2012); wheat straw (Tilay, Bule, Kishenkumar, & Annapure, 2008); hazelnut shell (Shahidi, Alasalvar, & Liyana-Pathirana, 2007); brazilnut shell (John & Shahidi, 2010); almond shell (Moure, Dominguez, & Parajo, 2008); walnut shell (Salcedo, Lopez de Mishima, & Nazareno, 2010); sunflower seed husk (De Leonardis, Macciola, & Di Domenico, 2005) and Phaseolus vulgaris seed coat (Dinelli et al, 2006).…”

Evaluation of antioxidant activity of dilute acid hydrolysate of wheat straw during xylose production

“…When the overall xylose yield and phenolic content of the acid hydrolysate of wheat straw were compared with those obtained from previous studies carried out for the production of xylose (Roberto et al, 2003;Akpinar et al, 2010b) and phenolic compounds (Moure et al, 2008) from lignocellulosic materials with acid hydrolysis, it was found that the xylose yield and the phenolic contents were similar. The results showed that increase in severity of the hydrolysis conditions of wheat straw resulted with increase in phenolic yields and decrease in xylose yield.…”

“…While hot water can extract the free phenolic acids, acid hydrolysis can release simple esterified phenolic acids. These phenolics, considered as the byproducts of acid hydrolysis of lignocellulosic materials, have potential application as food additives with antioxidant activity (Moure et al, 2008). The acid-soluble lignin fractions such as p-hydroxybenzoic acid, ferulic acid, vanillic acid, syringic acid, coumaric acid, syringaldehyde, p-hydroxybenzaldehyde and vanillin are well known.…”

The Effect of Waste Fodder Potato Proteins on the Mechanical Properties of Carboxylated Acrylonitrile-Butadiene Rubber

“…Therefore their total recovery seems to be justified. Some like Kudo and others [1][2][3] noticed that the peptides isolated from potato protein hydrolyzate have antioxidant properties, which are unusually profitable if used as a potential addition to food.…”

“…The composition of potato sewage is 20-25% proteins and amino acids, 15% sugar and 20% mineral components, 14% organic acids, and other compounds such as phenolic compounds. Many researchers indicate the antioxidant properties of potato protein hydrolyzates [2][3][4][5]. Literature overview reported that waste potato proteins found application in the production of bioethanol from potato cell sap [6][7][8].…”