Phenolic Compounds and Fatty Acids from Acorns (Quercus spp.), the Main Dietary Constituent of Free-Ranged Iberian Pigs

Abstract

The aim of the present work was to identify and quantify the phenolic compounds and fatty acids in acorns from Quercus ilex, Quercus rotundifolia, and Quercus suber. The concentration of oleic acid was >63% of total fatty acids in all cases, followed by palmitic and linoleic acids at similar concentrations (12-20%). The concentrations of alpha-tocopherol in Q. rotundifolia, Q. ilex, and Q. suber were 19, 31, and 38 mg/kg of dry matter (DM), respectively, whereas the concentrations of gamma-tocopherol were 113, 66, and 74 mg/kg of DM, respectively. Thirty-two different phenolic compounds were distinguished. All of them were gallic acid derivatives, in the form of either galloyl esters of glucose, combinations of galloyl and hexahydroxydiphenoyl esters of glucose, tergallic O- or C-glucosides, or ellagic acid derivatives. Several tergallic acid C-glucosides were also present in the extracts obtained from Q. suber. Acorns from Q. ilex and Q. rotundifolia showed similar polyphenol patterns mainly with gallic acid-like spectra. Chromatograms of Q. suber showed mainly polyphenols with ellagic acid-like spectra. Valoneic acid dilactone was especially abundant in Q. suber skin. The contribution of skin to the total phenolics of the acorn was relatively small in Q. rotundifolia and Q. ilex but relatively high in Q. suber. Skin extracts from Q. suber, Q. rotundifolia, and Q. ilex showed 1.3, 1.4, and 1.0 antioxidant efficiencies, respectively (compared to that of butylhydroxyanisole). Endosperm extracts showed lower capacity to prevent lipid peroxidation than skin extracts.

Characterization of phenolic compounds in wild medicinal flowers from Portugal by HPLC–DAD–ESI/MS and evaluation of antifungal properties

“…All the studied plant extracts presented compounds that showed UV spectral coherent with galloyl and hexahydroxydiphenol (HHDP) derivatives (Cantos et al, 2003), and in accordance with their mass spectra data, they were associated to different isomers of trigalloyl glucopyranose and di, trigalloyl-hexahydroxydiphenoyl glucopyranose ( Table 1). According to the literature, the main characteristic in the mass spectra of these compounds was the deprotonated molecula [M-H] - (m/z 483, 635, 787, 939, 785, 937) and the loss of one or more galloyl groups (152 mu) and/or gallic acid (170 mu) (Salminen et al, 1999;Zywicki et al, 2002) As far as we know, there was no information on the phenolic composition of C. sativa and R. micrantha flowers, but a few previous studies have been published dealing with the phenolic composition of F. ulmaria flowers from Russia Krasnov et al, 2009;Shilova et al, 2006), Poland (Fecka, 2009) and Austria (Pemp et al, 2007).…”

Dose-Response Relationship between Dietary Polyphenols from Acorns and Parotid Gland Hypertrophy in Pigs

“…More than 500 species of Oaks are spread out all over the world, differing in chemical composition and polyphenols contents. In general terms, literature reports that condensed tannins represented about 1% -2% of DM [65,68,69], across different botanical species of oaks, while hydrolizable tannins are much more abundant and can range from 5% up to 10% on DM [65,68,70]. The use of acorns as food is known since ancient times and the worldwide deployment across cultures and centuries is well documented in traditional recipes, above all for flour and bread production, but also for oil extraction [67,[71][72][73][74][75][76].…”

Phenolic and furanic compounds of Portuguese chestnut and French, American and Portuguese oak wood chips

“…Some of these compounds are hydrolysable tannins since they can be hydrolyzed leading to the formation of gallic acid and/or ellagic acid. Those compounds were identified by their HPLC-DAD/ESI-MS and also by comparing these data with the literature [35][36][37]. Concerning the UV spectrum, the identified compounds belong to two main groups.…”

“…Low molecular weight compounds were identified by comparing their retention times and UV and mass spectra with those of the standards. Additionally, 17 peaks corresponding to compounds with related structures were tentatively identified on the basis of their retention time, UV spectra and MS patterns, as well as taking into account data in related literature [35][36][37]. Most of those compounds tentatively assigned were hydrolysable tannins, which comprise gallotannins and ellagitannins.…”