Acorn ( Quercus spp.) fruit lipids: Saponifiable and unsaponifiable fractions: A detailed study

Effect of geographical origin on the chemical characteristics of Q. canariensis acorns: profiling fatty acids, tocopherols, and phenolic composition

The impact of geographical origin on the chemical composition of acorns from Quercus species has significant attention. This study aimed to explore the phenolic composition of methanolic extracts, tocopherol content, and fatty acid composition of acorn oils from six different populations of Q. canariensis acorns. The obtained results revealed that acorn oil from BniMtir exhibited high levels of α-tocopherol (58 mg/kg). The fatty acids identified across all samples were Z-vaccenic + oleic acids (38.44-58.58%). In addition, the data highlighted the presence of quinic (32.514-60.216 µg/g DW) and gallic acids (1.674-10.849 µg/g DW), as well as catechin (+) (0.096-12.647 µg/g DW) in all populations. These variations in chemical composition from different regions are likely linked to their geographical origin. In conclusion, this study's finding should significance for the industry, offering valuable insights into the potential production of bioactive compounds from Q. canariensis acorns, which could have various applications.

Unveiling the Use of Wide Horizontal Rim Vessels (Bronze Age Northwest Iberian Peninsula)

This paper addresses a “wide horizontal rim vessel” belonging to the collection of Fundação Sousa d’Oliveira (Azores). Although its provenance and the circumstances of its discovery are currently unknown, the authors contend that this vessel should be attributed to the Iberian Northwest and, more specifically, to the Portuguese territory, in line with the highly homogenous distribution of this type of pottery. A morphological and stylistic study has been carried out establishing its singularity with regards to the decorative composition of the rim, which is without parallel amongst dozens of vessels of the same “family”. During the study of this piece, it has been possible to observe traces of soot and organic residues deposited both on its interior and exterior surfaces, which is recurrent in these vessels. The nature of these substances has never been determined in previous studies. In this article, we present and discuss the results obtained from the chromatographic analyses of the organic residue traces found on the vessel.

Effects of daily functional acorn cake consumption on insulin resistance in individuals with obesity or overweight and the metabolic syndrome: a placebo-controlled randomised clinical trial

The metabolic syndrome is a multi-factorial condition and functional foods need more investigation as novel adjunct treatments for this group. This study aimed to determine the effects of daily consumption of a functional acorn cake in conjunction with energy restriction (119.50 kJ) on individuals with overweight or obesity and the metabolic syndrome. In this randomised double-blinded study, eighty-four participants were randomly allocated to either an energy-restricted diet plus two servings (2 × 30 g)/d of functional acorn cake (a cake made of acorn for the intervention group) (FC) (n 42) or an energy-restricted diet plus placebo cake (PC) (n 42). Body composition and biochemical parameters were measured before and after 10 weeks of intervention. Seventy-three participants completed this trial. No differences in loss of body weight, waist circumference, fat mass, fasting blood glucose and blood pressure were shown between two groups. Body weight decreased by 4·2 (sd 1·9) kg and 5·1 (sd 2·8) kg in PC and FC groups, respectively. Compared with PC, the consumption of FC resulted in a significant reduction in serum insulin (P = 0·02), homoeostasis model assessment for insulin resistance (P = 0·02), high-sensitivity C-reactive protein (P = 0·04) and a significant increase in adiponectin concentration (P = 0·04). Although lipid metabolism did not differ among groups, total cholesterol and HDL-cholesterol improved non-significantly in the FC group. Functional acorn cake as an adjunct to energy restriction could possibly improve insulin resistance in individuals with obesity. Further research is needed to elucidate whether functional acorn cake can be used as a preventive strategy for the metabolic syndrome in individuals with obesity.

Variations in Acorn Traits in Two Oak Species: Quercus mongolica Fisch. ex Ledeb. and Quercus variabilis Blume

Quercus mongolica Fisch. ex Ledeb. and Q. variabilis Blume are two main oak species in China, producing large amounts of acorns every year. However, the trait variations in acorns, as a promising energy crop material, are not fully understood, hence we compared the traits of acorns from the different populations with the altered geographic distribution in this study. Thirteen acorn traits, including phenotype, proximate compositions and functional compounds, were analyzed in both Quercus L. species collected from 44 populations across China. The results showed that, except large differences found among accessions in acorn sizes, the starch varied from 140.96–297.09 mg/g in Q. mongolica and 130.99–306.28 mg/g in Q. variabilis, indicating its substantial differences among populations. The total polyphenols, total flavonoids and soluble tannins varied from 41.76–158.92, 23.43–91.94, and 15.11–17.81 mg/g, respectively, in Q. mongolica, 89.36–188.37, 50.59–116.07, 15.24–17.33 mg/g, respectively, in Q. variabilis, demonstrating their large variations in the levels of polyphenols among populations. Moreover, the acorns of Q. mongolica in North China and Q. variabilis in Southwest China had higher levels of starch and polyphenols. As the geographical location approached in the distribution of two Quercus species, the difference in acorn sizes gradually increased, while that in polyphenols were opposite. Principal component analysis and cluster analysis further revealed that the acorn sizes became larger and polyphenols became less with the increasing latitudes in both species. In North China, the acorns of Q. mongolica had small sizes and high polyphenols, which was contrary to those in Q. variabilis. These findings indicated that acorn traits were closely associated with the geographical distribution. Thus, our results will provide references for the selection breeding of acorn with the high starch, high or low polyphenols in the different regions.

In silico analysis of the antimicrobial activity of phytochemicals: towards a technological breakthrough

BACKGROUND

The complications associated with infections from pathogens increasingly resistant to traditional drugs lead to a constant increase in the mortality rate among those affected. In such cases the fundamental purpose of the microbiology laboratory is to determine the sensitivity profile of pathogens to antimicrobial agents. This is an intense and complex work often not facilitated by the test's characteristics. Despite the evolution of the Antimicrobial Susceptibility Testing (AST) technologies, the technological breakthrough that could guide and facilitate the search for new antimicrobial agents is still missing.

METHODS

In this work, we propose the experimental use of in silico instruments, particularly feedforward Multi-Layer Perceptron (MLP) Artificial Neural Network, and Genetic Programming (GP), to verify, but also to predict, the effectiveness of natural and experimental mixtures of polyphenols against several microbial strains.

RESULTS

We value the results in predicting the antimicrobial sensitivity profile from the mixture data. Trained MLP shows very high correlations coefficients (0,93 and 0,97) and mean absolute errors (110,70 and 56,60) in determining the Minimum Inhibitory Concentration and Minimum Microbicidal Concentration, respectively, while GP not only evidences very high correlation coefficients (0,89 and 0,96) and low mean absolute errors (6,99 and 5,60) in the same tasks, but also gives an explicit representation of the acquired knowledge about the polyphenol mixtures.

CONCLUSIONS

In silico tools can help to predict phytobiotics antimicrobial efficacy, providing an useful strategy to innovate and speed up the extant classic microbiological techniques.

Analysis and determination of phytosterols and triterpenes in different inbred lines of Djulis (Chenopodium formosanum Koidz.) hull: A potential source of novel bioactive ingredients

Djulis (Chenopodiun formosaneum Koidz.,), pseudo-cereal crop emerged as a potential source of functional ingredients, was used to identify phytosterols and triterpenes from seven inbred lines of Djulis hull using GC-MS. Key bioactive compounds were identified including 6 phytosterols (34.73-59.48 mg/100 g), 6 triterpenes (30.56-57.47 mg/100 g), and 5 other unsaponifiable compounds (15.89-22.50 mg/100 g). Moreover, principal component analysis (PCA) was conducted and explored the variation among Djulis hull samples with two clusters based on the surface color that reflected the content of phytosterols and triterpenes. These results confirmed that the color might be used as an indicator for estimation of phytosterol and triterpene contents in Djulis hull. Overall, this is the first study that identified novel unsaponifiable compounds in Djulis hull, which might contribute to the development of phytosterols and/or triterpenes enriched functional foods.

Antioxidant activity, tocopherols and polyphenols of acornoil obtained from Quercus species grown in Algeria

Among the unusual vegetable fats, acorn oil has interesting nutritional and functional properties. Few studies are present in literature on acorn oil characterization and antioxidant activity evaluation while no studies are present regarding the analysis of the phenolic profile. The present study aims at investigating the content of hydrophilic and lipophilic phenolic compounds and pigments, as well as antioxidant properties and quality of the oil extracted from three Quercus species grown in Algeria. Oil yield, expressed as dry weight, was in the range 7.05-8.40%. Tocopherols contents were remarkable for the three species (539-676 mg kg^-1), with (β + γ)-tocopherols being the most abundant. Oils had also significant amounts of carotenoids (42-66 mg kg^-1) and similar polyphenol patterns, but with a wide quantitative variability between species (195-436 mg kg^-1). Twenty phenolic compounds were detected, 12 of which were tentatively identified. All of them were hydrolysable tannins derivatives (gallotannin or ellagitannin). Oils methanolic extracts had remarkable antioxidant activity; up to 3.34 and 3.79 μmol TE g^-1 oil (DPPH and ABTS test, respectively). Quercus oil is a potential source of natural antioxidants, and it could be used as a new functional oil.

Effect of acorn meal-water combinations on technological properties and fine structure of gluten-free bread

Gluten-free breads were developed from rice flour and corn starch at a constant ratio 1:1 with acorn meal addition (5, 15, 25%), at three levels of water (65, 70, 75%). Acorn supplemented gluten free breads better met sensory preference than rice breads in terms of colour (brown hue was enhanced) and were also nutritionally improved in terms of total phenolics. The specific volume of breads significantly decreased with increasing acorn addition while crumb hardness was also increased. SEM images confirmed that the decrease in the ΔH values at low water level (65%) was due to less swelling of starch as observed from large starch granule remnants present after baking. XRD measurements revealed coexistence of "B" and "V" type starch structures. Increasing of acorn concentration enhanced the intensity of FTIR bands at 994, 1016 and 1077 cm^-1.

Impact of hydrothermal modifications on the physicochemical, morphology, crystallinity, pasting and thermal properties of acorn starch

Native acorn starch had high purity and the granules were mainly elliptical and spherical with the mean diameter of 7.32 μm. Hydrothermal modifications slightly changed the morphology. The solubility, swelling properties and amylose leaching of acorn starch were mostly influenced by Heat-moisture treatment (HMT). XRD pattern of native starch (C-type) did not change on hydrothermal modifications, but native and annealing (ANN) modified starches showed the most crystallinity. DSC results showed that the gelatinization temperatures and enthalpy of native starch were 59.9, 71.3, and 80.6 °C and -14.9 mJ/mg, respectively, and hydrothermal treatments generally increased the gelatinization temperatures. Regarding to RVA results, peak, breakdown, trough, setback, and final viscosities of native starch were 415, 143, 272, 168, and 440 RVU, respectively, and viscosity parameters of native starch were mainly more than those of hydrothermally modified starches. Generally, the intensity of the effects of hydrothermal modifications followed the order: HMT > dual modifications > ANN.

Acorn (Quercus spp.) as a novel source of oleic acid and tocopherols for livestock and humans: discrimination of selected species from Mediterranean forest

The aim of the present work was to characterization and compare acorns from selected Quercus spp. from the Mediterranean forest in Spain, namely, Portuguese oak (QF, Quercus faginea Lam.), Cork oak (QS, Quercus suber L.), Pyrenean oak (QP, Quercus pyrenaica Wild), Kermes oak (QC, Quercus coccifera L.), Holm oak (QB, Quercus ilex L. subsp. ballota [Desf.]). All physicochemical attributes varied significantly between species. Fat contents ranged from 1.30 to 4.70 g 100 g-1 fresh matter. The most abundant fatty acids were oleic (62.44, 56.25, 57.46, 48.02, 65.83%), followed by linoleic (16.42, 20.73, 21.30, 25.38, 14.17%) and palmitic (11.69, 14.27, 12.17, 16.22, 12.28) acids in QF, QS, QP, QC and QB species, respectively. The tocopherol content was high in the range of 31.83-45.25 mg kg-1, and γ-tocopherol constituted 67-78% of total tocopherols. Only an effect of the location on γ-tocopherol content in QB was observed. The present results show the potential of different species of acorn to be used as agricultural and food resources and that geographical location plays a secondary role.

A New Age for Quercus spp. Fruits: Review on Nutritional and Phytochemical Composition and Related Biological Activities of Acorns

The current global food system must adapt to the expected growth of world population (about 9 billion individuals by 2050). This adaptation will probably include an increased consumption of edible wild foods, due to their richness in micronutrients and bioactive compounds, besides providing a cost-effective and sustainable way of improving caloric food security. A striking example of such natural matrices is the Quercus genus, which has the additional advantage of being widespread throughout the Northern Hemisphere. In a traditional sense, Quercus fruits (acorns) were mainly used in animal feeding, despite their potentially important role on the rural economy. But this preconception is changing. In fact, their nutritional value, high contents in phytochemical compounds, biological activity (such as antioxidant, anticarcinogenic, and cardioprotective properties) and use in the treatment of specific diseases (such as atherosclerosis, diabetes, or Alzheimer's disease) have raised the interest in integrating acorns into the human diet. Accordingly, this comprehensive overview was designed to provide an evidence-based review of the literature, with the objective to achieve useful conclusions regarding the nutritional properties, methodologies of extraction, identification, and characterization of a wide variety of bioactive compounds and scientifically validated bioactivities in Quercus species worldwide. The industrial by-products from acorn oil extraction or flour production are also included. Data regarding the analytical techniques, individual compounds, and their bioactivities, are organized in tables. The reported data are discussed and directions for further investigations are suggested, highlighting the use of acorns in food, nutraceutical, and pharmaceutical applications.

Triacylglycerols and aliphatic alcohols from fruits of three Tunisian Pistacia lentiscus populations

BACKGROUND

The search for other sources of vegetable oils by the exploitation and the enhancement of other oil plants will be needed to meet the demands of the international market. This study aims to determine the triacylglycerol (TAG) molecular species and aliphatic alcohol compositions of unexploited fruits of three Tunisian Pistacia lentiscus (lentisc) populations from the Korbous, Tebaba and Rimel areas of Tunisia.

RESULTS

Results show that the content of total TAG varies from 738.32 mg g(-1) of total lipid in the Tebaba population to 981.15 mg g(-1) of total lipid in the Korbous population. Furthermore, 14 species of TAG were detected in the three studied populations. In addition, 13 aliphatic compounds were identified and classified into two groups: (1) aliphatic alcohols with fewer than 20 carbon atoms (hexadecanol, heptadecanol, (Z)-octadec-9-en-1-ol, octadecanol and nonadécanol); and (2) the policosanol group (eicosenol, docosenol, docosanol tetracosanol, hexacosanol octacosanol and triacontanol). The Tebaba population showed a distinct composition compared to Korbous and Rimel where heptadecanol is the major compound.

CONCLUSION

Quantitatively, the most abundant TAG species are those constituted by palmitic, oleic and/or linoleic acid. Furthermore, the significant difference observed at the oil composition is associated with a remarkable station effect.

Antioxidant characterization of oak extracts combining spectrophotometric assays and chemometrics

Antioxidant characteristics of leaves, twigs, and acorns from two Serbian oak species Quercus robur L. and Quercus petraea L. from Vojvodina province (northern Serbia) were investigated. 80% ethanol (in water) extracts were used for antiradical power (ARP) determinations against DPPH(•), (•)NO, and O2 (•-) radicals, ferric reducing antioxidant power (FRAP), total phenol, tannin, flavonoid, and proanthocyanidin contents. Permanganate reducing antioxidant capacity (PRAC) was determined using water extracts. Beside, mentioned parameters, soluble proteins, lipid peroxidation (LP), pigments and proline contents were also determined. The data of different procedures were compared and analyzed by multivariate techniques (correlation matrix calculation and principal component analysis (PCA)). PCA found that investigated organs of two different oak tree species possess similar antioxidant characteristics. The superior antioxidant characteristics showed oak leaves over twigs and acorns and seem to be promising source of antioxidants with possible use in industry and pharmacy.

Chemical Composition and Antioxidant Activity of the Essential Oil and Fatty Acids of the Flowers of Rhanterium Adpressum

The essential oil obtained by hydrodistillation of the flowers of Rhanterium adpressum Coss. & Durieu was analyzed using GC and GC-MS. The essential oil was very rich in monoterpene compounds. The major components identified were the monoterpene hydrocarbons: camphene (21.8%), myrcene (19.3%) and α-pinene (17.4%). Other compounds, including limonene, β-pinene and terpinol-4-ol, were present in low content (4–6%). The composition of the fatty acids in the lipid extract obtained from the flowers was also investigated by GC and GC-MS. The main fatty acids identified were palmitic (47.4%), oleic (12.9%) and stearic acids (10.6%). The total phenolic contents and the antioxidant activities were also evaluated for both extracts. The total phenolic contents were determined using the Folin-Ciocalteu reagent and the antioxidant activities were measured using three different assays: DPPH (1,1-diphenyl-2-picrylhydrazyl) free radical scavenging activity, FRAP (ferric reducing antioxidant potential) and a molybdenum assay. As a result of these tests, the lipid extract exhibited the highest antioxidant activities in comparison with the essential oil extract.

Acorn crop size and pre-dispersal predation determine inter-specific differences in the recruitment of co-occurring oaks

The contribution of pre-dispersal seed predation to inter-specific differences in recruitment remains elusive. In species with no resistance mechanisms, differences in pre-dispersal predation may arise from differences in seed abundance (plant satiation) or in the ability of seeds to survive insect infestation (seed satiation). This study aimed to analyse the impact of pre-dispersal acorn predation by weevils in two co-occurring Mediterranean oaks (Quercus ilex and Quercus humilis) and to compare its relevance with other processes involved in recruitment. We monitored the patterns of acorn production and acorn infestation by weevils and we conducted experimental tests of acorn germination after weevil infestation, post-dispersal predation and seedling establishment in mixed forests. Monitoring and experimental data were integrated in a simulation model to test for the effects of pre-dispersal predation in recruitment. In both oaks pre-dispersal acorn infestation decreased with increasing acorn crop size (plant satiation). This benefited Q. ilex which exhibited stronger masting behaviour than Q. humilis, with almost a single and outstanding reproductive event in 6 years. Acorn infestation was more than twice as high in Q. humilis (47.0%) as in Q. ilex (20.0%) irrespective of the number of seeds produced by each species. Although germination of infested acorns (seed satiation) was higher in Q. humilis (60%) than in Q. ilex (21%), this could barely mitigate the higher infestation rate in the former species, to reduce seed loss. Conversely to pre-dispersal predation, no inter-specific differences were observed either in post-dispersal predation or seedling establishment. Our results indicate that pre-dispersal predation may contribute to differences in seed supply, and ultimately in recruitment, between co-existing oaks. Moreover, they suggest that seed satiation can barely offset differences in seed infestation rates. This serves as a warning against overemphasising seed satiation as a mechanism to overcome seed predation by insects.

Determination of ent-kaurene in subcutaneous fat of Iberian pigs by gas chromatography multi-stage mass spectrometry with the aim to differentiate between intensive and extensive fattening systems

This work presents a gas chromatography multi-stage mass spectrometry (GC-MS(3)) method for the determination of ent-kaurene in subcutaneous fat of Iberian pig, present in adipose tissue of animals due to pasture ingestion (extensive fattening system). The method comprises a saponification and a liquid-liquid extraction of the unsaponifiable fraction, followed by an isolation of the hydrocarbon fraction by high performance liquid chromatography (HPLC) and analysis by GC-MS(3) (ion trap) with electronic ionization. The GC-MS(3) analysis allows the isolation and characterization of specific fragments from the original (MS(1)) molecular structure, and particularly, those fragments originated from the precursor ion (m/z=229) characteristic of ent-kaurene. The MS/MS product fragment m/z=213 is used as a further precursor fragment giving rise to a MS(3) spectrum specific for ent-kaurene. The limit of detection of the MS(3) technique is lower than 0.2 microg kg(-1) and a linear regression has been found between 0.2 and 112 microg kg(-1). This method is applicable for the determination of the fattening system of the Iberian pig.

Characterization and quantification of the hydrocarbons fraction of the subcutaneous fresh fat of Iberian pig by off-line combination of high performance liquid chromatography and gas chromatography

Hydrocarbons in fresh subcutaneous fat of Iberian pig have been analyzed by GC-MS after fractionation of the unsaponifiable fraction with a new off-line combination of HPLC and GC method. The new method proposed improves the recovery and simultaneous quantification of terpenic hydrocarbons in comparison to the traditional LC method. When necessary and for identification purposes, selective ion monitoring (SIM) was used as acquisition mode in GC-MS. To determine the position of the double bonds in the unsaturated hydrocarbon chain the dimethyl disulfide derivatives (DMDS) were obtained. To elucidate the structure of the branched 1-alkenes the hydrocarbon fraction was submitted to hydrogenation. Thirty-five compounds have been identified, including n-alkanes, n-alkenes, branched (n-1,n-2-dimethyl-1-alkenes) and terpenic hydrocarbons, being the most abundant n-alkenes and n-alkanes of even chain of n-C12-n-C26. Besides the hydrocarbons already described in bibliography, a new diterpenic hydrocarbon, ent-kaurene, have been identified for the first time. The compound reported as Neophytadiene by other authors, has been identified as a 20 atoms hydrocarbon with two double bonds, the 7,11,15-trimethyl-heptadeca-1,4-diene.