Antioxidant properties of roasted apricot (Prunus armeniaca L.) kernel

The antioxidant properties of peeled, defatted and roasted apricot kernel flours were evaluated by determining radical scavenging power (RSP), anti-lipid peroxidative activity (ALPA), reducing power (RP), total phenolic content (TPC), assessed by DPPH test, β-carotene bleaching method, iron (III to II) reducing test and Folin method, respectively. Browning degree of the samples was also measured and found to increase almost linearly with the roasting time. Contrary to browning degree, RSP, RP and TPC did not increase linearly but showed a maximum for 10 min of roasting. Roasting reduced the ALPA values, thus unroasted sample showed the highest ALPA value. RSP, RP and TPC measurements of all samples, were in high correlation (at least, r = 0.92).     

Some compositional properties of main Malatya apricot (Prunus armeniaca L.) varieties

Malatya apricot (Prunus armeniaca L.) varieties are among the most important agricultural products of Turkey and protected as a geographical indication. In this research, it was aimed to determine some important analytical properties (dry matter, soluble solid content, a_w, ash, titratable acidity, pH, color, total phenolics, total carotenoids, β-carotene, sugars, organic acids, and mineral content) of Malatya apricots and to reveal the characteristic properties that differ these products from the similar ones. The apricot varieties, namely Hac?halilo?lu, Hasanbey, So?anc?, Kabaa??, Çatalo?lu, Çölo?lu, and Hac?k?z that are widely cultivated in Malatya region and other regions (Ere?li, ?zmir, I?d?r, and Bursa) of Turkey were involved in the study. All analytical properties were found to be significantly different (p < 0.05) among different apricot varieties. The results have shown that dry matter and sugar content of Malatya apricot varieties are considerably higher than the other apricot varieties investigated in this study, as well as the data of other researches on apricots. All apricot varieties were found to be a good source of phenolic compounds (4233.70–8180.49 mg of gallic acid equiv/100 g of dry weight), carotenoids (14.83–91.89 mg of β-carotene equiv/100 g of dry weight), and β-carotene (5.74–48.69 mg/100 g of dry weight). Sucrose, glucose, and fructose were determined as the major sugars in all apricot varieties. In addition, sorbitol contents (16.91–26.84 mg/100 g of dry weight) of Malatya apricots were remarkably higher than the other apricot varieties. This was considered to be the one of the unique properties of Malatya apricots. Malic acid was the predominant organic acid in all Malatya apricot varieties. The results have also shown that the potassium content of Malatya apricots was significantly high and these apricots were important sources of Mg, Zn, and Se. This study has revealed that Malatya apricot contains functional food components with high nutritional value.     

Changes in physicochemical characteristics and volatile compounds of apricot (Prunus armeniaca L. cv. Bergeron) during storage and post-harvest maturation

The effects of storage and post-harvest maturation on the physicochemical characteristics and volatile constituents of Bergeron apricot were investigated during the 2007 season over two experiments. Fruits, harvested at two distinct stages of maturity, in two different experimental orchards, were stored in cold chambers at +1 °C for up to 3 weeks and then subjected to a post-harvest maturation in ripening chambers at 20 °C and 60–70% RH up to 7 days. Firmness, soluble solids (SS), titratable acidity (TA), and the levels of the main volatiles were determined. Physicochemical changes included a significant decrease of firmness during both storage and post-harvest maturation whereas the levels of SS and TA were found to be very similar. The results also indicated that, whatever their initial stage of maturity at harvest, the rates of softening of apricots during storage and/or post-harvest maturation were very comparable. During post-harvest maturation, the levels of C₆-compounds decreased drastically whereas, at the same time, those of esters, lactones and terpenic compounds greatly increased. During storage at 1 °C, a decrease of C₆-compounds was also observed. As regards other compounds, there were some statistically different results between samples but the changes observed for lactones, esters and terpenic compounds were relatively small in comparison to those observed during post-harvest maturation at 20 °C. The results also showed that, at the end, qualitative and quantitative differences can be observed in the “ready-to-eat” apricots according to their initial stage of maturity at harvest. On average, apricots harvested at the most advanced stage of maturity have, on average, the highest levels of soluble solids and the highest levels of volatile compounds of interest.     

The influence of electron-beam ionization on ethylene metabolism and quality parameters in apricot (Prunus armeniaca L., cv Búlida)

The possibility of extending the post-harvest shelf-life of apricots (Prunus armeniaca, Búlida) by applying electron-beam ionization at doses of 0.5 and 1.0 kGy has been studied. Ionization treatment caused a decrease in the ethylene concentration in the climacteric peak; this effect was more pronounced at the greater dose (1.0 kGy). The free 1-aminocyclopropane-1-carboxylic acid (ACC) increased in control fruits and in those treated at 0.5 kGy, while it decreased at 1.0 kGy. The conjugated ACC showed an initial increase, sharper in control fruits, and a later decrease during the whole experiment. Both ACC synthase and ACC oxidase showed a lower maximum activity in ionized fruits than in control fruits. The texture of ionized fruits showed a higher loss of firmness than untreated fruits during storage, especially when they were ionized at doses of 1.0 kGy. However, the other physico-chemical parameters studied, color, total soluble solids content (TSSC), titrable acidity (TA), and carotenoids, showed no significant changes between control and ionized apricots. The ionization treatment at 0.5 or 1.0 kGy, despite its influence on the ethylene metabolism of fruit, was not effective for extending the shelf-life of apricot variety Búlida since, during storage, no significant differences between control and treated apricots were found in the physico-chemical parameters indicative of ripening.     

The importance of almond (Prunus amygdalus L.) and its by-products

Almond fruit consists of three or correctly four portions: kernel or meat, middle shell, outer green shell cover or almond hull and a thin leathery layer known as brown skin of meat or seedcoat. The nutritional importance of almond fruit is related to its kernel. Other parts of fruit such as shells and hulls were used as livestock feed and burned as fuel. In the past decades, different phenolic compounds were characterised and identified in almond seed extract and its skin, shell and hull as almond by-products. In addition, polyphenols are abundant micronutrients in the human diet, and evidence for their role in the prevention of degenerative diseases such as cancer and cardiovascular diseases is emerging. The health effects of polyphenols depend on the amount consumed and on their bioavailability. In this contribution, various phenolic compounds present in almond and its by-products, their antioxidant properties and potential use as natural dietary antioxidant, as well as their other beneficial compounds and applications are reviewed.     

Antioxidant activities of phenolic rich fractions (PRFs) obtained from black mahlab (Monechma ciliatum) and white mahlab (Prunus mahaleb) seedcakes

The antioxidant activities of phenolic rich fractions (PRFs) from crude methanolic extract (CME), and its fractions using ethyl acetate (EAF), hexane (HF) and water (WF) of black mahlab (Monechma ciliatum) and white mahlab (Prunus mahaleb) seedcakes were investigated. The total phenolic compounds were found to be higher in white mahlab than black mahlab seedcakes. The antioxidant activity determined by the DPPH method revealed that black mahlab PRFs had the highest antioxidant activity, compared to white mahlab fractions. The presence of antioxidants in the two mahlab PRFs reduced the oxidation of β-carotene by hydroperoxides from these extracts/fractions. The effect of the two mahlab PRFs on the oxidative stability of corn oil at 70 °C was tested in the dark and compared with butylated hydroxyanisole (BHA). The CME performed better antioxidant activity in inhibiting the formation of both primary and secondary oxidation products. The qualitative and quantitative characterisation of phenolic compounds was carried out by HPLC/DAD.     

Phenolic compounds from the edible seeds extract of Chinese Mei (Prunus mume Sieb. et Zucc) and their antimicrobial activity

Prunus mume seeds have been used as a healthy food and traditional drug in China. The present study investigated the phenolic compounds and antimicrobial activity of ethanolic extract from seeds of P. mume. Total phenolic content was determined as gallic acid equivalents by the Folin-Ciocalteu method. The antibacterial activity was measured by a filter paper disc method. Three chlorogenic acid isomers, namely, 3-O-caffeoylquinic acid, 5-O-caffeoylquinic acid and 4-O-caffeoylquinic acid, were identified from P. mume seeds for the first time. The contents of these isolated compounds were quantified by HPLC. Results showed that 3-O-caffeoylquinic acid was of the highest level in these three isomers. The ethanolic extract exhibited inhibition activity against bacteria and fungi obviously. The isolated phenolic compounds also exhibited inhibition activity against bacteria significantly, but showed weak or no inhibition activity against yeasts and mold. The results exhibited that the antimicrobial activity of P. mume seeds may be partly due to the phenolic compounds.     

Chemical composition and biological activities of Algerian Thymus oils

The compositions of essential oils isolated from nine samples of three Thymus species (Thymus algeriensis, Thymus pallescens and Thymus dréatensis) were analysed by GC and GC–MS, and a total of 114 components were identified. T. pallescens collected from various regions showed a great similarity in their compositions and were characterised by carvacrol (44.4–57.7%), p-cymene (10.3–17.3%) and γ-terpinene (10.8–14.2%) as the major components for four samples; only one sample was thymol-rich (49.3%) with a small amount of carvacrol (9.0%). On the other hand, T. algeriensis showed a chemical polymorphism, even for samples from the same location, and two new chemotypes for this species were proposed. Oxygen-containing monoterpenes were the predominant class (76.3%) in T. dreatensis oil, with linalool (30.4%), thymol (20.2%) and geraniol (19.6%) as the principal constituents. The oils were screened for their possible antioxidant activities by four complementary assays, namely DPPH free radical scavenging, hydroxyl radical scavenging, inhibition of lipid peroxidation and reducing power. The two new chemotypes of T. algeriensis exhibited strong hydroxyl radical scavenging (IC₅₀ = 2.2–3.3 μg/ml), but were not or only slightly active against the other radicals and exhibited a weak reducing power. Despite their chemical similarity, T. pallescens oils sometimes produced significant differences in their antioxidant activities. The essential oils were also screened for their antimicrobial activity against five bacteria (three Gram-positive and two Gram-negative) and one yeast (Candida albicans). The tested essential oils showed antimicrobial activity against the microorganisms used, in particular against two important pathogens, C. albicans and Helicobacter pylori.     

Extractable antioxidants and non-extractable phenolics in the total antioxidant activity of selected plum cultivars (Prunus domestica L.): Evolution during on-tree ripening

The purpose of this study was to evaluate the contribution of extractable antioxidants and non-extractable phenolics to the total antioxidant activity (TAA) of plums. Therefore, the antioxidant activity was determined (ABTS assay) in aqueous–organic extracts, as well as in the extraction residues which were a subject of two different acidic treatments to release hydrolysable tannins and non-extractable proanthocyanidins (NEPA). In addition, the changes in TAA during the last week of ripening were investigated. Extractable antioxidants contributed less than 18% to the TAA, considerably higher values of antioxidant activity were associated with hydrolysable tannins and NEPA, suggesting that the antioxidant activity of plums may be underestimated in the literature. The ripening resulted in an increase of TAA up to 38% in excess of the value determined on the first sampling date. TAA showed a similar pattern over the ripening period for all cultivars studied.     

Characterization of aroma potential of apricot varieties using different extraction techniques

Aroma compounds are presents in raw foods, freely and glycosidically-bounded (aroma precursors). In the present work, the volatile fraction of eight varieties of apricot were analyzed using simultaneous distillation extraction (SDE), solid phase extraction (SPE) with reverse phase (C18), liquid–liquid extraction (LLE) and headspace-solid phase microextraction (HS-SPME). The free aroma compounds were identified by GC–MS, finding common compounds such as linalool, α-terpineol, β-ionone and γ-decalactone and specific compounds due to the extraction method used. The ANOVA showed a significant effect in the extraction techniques and on the varieties in the free aromatic fraction from apricot as well. In spite of a large number of volatile compounds extracted by SPE, the technique that allowed for the most number of compounds to be extracted was SPME.     

Distribution of the volatile compounds in the different parts of a white-fleshed peach (Prunus persica L. Batsch)

The quantitative distribution of volatile compounds in the skin, top mesocarp, middle mesocarp, bottom mesocarp, inner mesocarp, and outer mesocarp of a white-fleshed peach (cv. Maura) was investigated. Volatile compounds were extracted by liquid–liquid microextraction (LLME) and analyzed by GC–FID and GC–MS. The results showed that the levels of volatiles in skin were significantly higher than those observed in the other parts of the fruit, whereas top and bottom mesocarp were mainly discriminated by opposite concentrations in unsaturated lactones and C₆-compounds. Distribution of lactones was also found to be different in skin and pulp according to their carbon chain length. Finally, the highest concentrations of benzaldehyde were found to be mainly located close to the stone suggesting that in peach this compound could be derived from enzymatic hydrolysis of amygdalin.     

Flavonoids of Zizyphus jujuba L. and Zizyphus spina-christi (L.) Willd (Rhamnaceae) fruits

The ripe edible fruits of jujube, Zizyphus jujuba Miller (syn. Z. sativa Gaertner, Z. vulgaris Lam.) and Christ’s thorn jujube Zizyphus spina-christi (L.) Willd (Rhamnaceae family) were phytochemically investigated, comparing their quali-quantitative flavonoids profile. Twelve compounds from both methanol extracts have been recognized as quercetin, kaempferol, and phloretin derivatives by means of HPLC/ESI-MS analyses. Six major compounds have been purified by Sephadex LH-20 column chromatography followed by HPLC and were characterized using NMR spectroscopy. One C-glycoside, 3′,5′-di-C-β-d-glucosylphloretin, was detected in Z. spina-christi. The quantitative analysis of all compounds was also reported showing a higher content of flavonoids in Z. jujuba.     

Effects of gamma irradiation on color characteristics and biological activities of extracts of Lonicera japonica (Japanese honeysuckle) with methanol and acetone

Effects of gamma irradiation on the color characteristic and biological activities of methanol and acetone extracts of Lonicera japonica (Japanese honeysuckle) irradiated at 0, 10, 20, and 30 kGy were investigated. Hunter color L^*- and a^*-value increased by irradiation in a dose-dependent manner, resulting in it being lighter than the nonirradiated, while Hunter color b^*-values decreased by irradiation (P<0.05). The extracts from L. japonica showed an inhibition effect against tyrosinase, xanthine oxidase and the nitrite scavenging ability. Tyrosinase inhibition effect of L. japonica was higher in the irradiated sample than the nonirradiated, and the effect was increased by irradiation doses. The L. japonica extracts had a higher inhibitory effect against xanthine oxidase, and the effect was not changed by irradiation. Nitrite scavenging activity was the highest in L. japonica extract at pH 1.2. The difference between solvents used was not detected. Thus, gamma irradiation may have no influence on the biological activities of the L. japonica extracts except for the tyrosinase inhibition effect when irradiated up to 30 kGy.     

Phenolic composition and biological activities of Salvia halophila and Salvia virgata from Turkey

The aerial parts of Salvia halophila and Salvia virgata were subjected to Soxhlet extraction with different solvents such as n-hexane, ethyl acetate, methanol, and aqueous methanol (50%). Plants were also extracted with water under reflux. The effects of the extracts were studied in p-benzoquinone-induced abdominal constriction test for the assessment of antinociceptive activity and carrageenan-induced hind paw edema and 12-O-tetradecanoyl-13-acetate (TPA)-induced ear edema models in mice for the anti-inflammatory activity. The extracts were analysed using a HPLC–PDA method. Results showed that methanol extract of S. virgata significantly inhibited carrageenan-induced paw edema and p-benzoquinone-induced abdominal constriction at 100 mg/kg dose, while it showed no effect in the TPA-induced ear edema. On the other hand, the other extracts did not show any inhibitory antinociceptive and anti-inflammatory activities in these in vivo models. Rosmarinic acid was found as main constituent in the extracts, while caffeic acid and luteolin derivatives were also detected.     

Antioxidant, antiacetylcholinesterase and antimicrobial activities of Cymbopogon schoenanthus L. Spreng (lemon grass) from Tunisia

Aqueous extract, proanthocyanidin rich extract, and organic extracts of Cymbopogon schoenanthus L. Spreng (lemon grass) shoots from three different locations in South Tunisia were screened for their antioxidant, acetylcholinesterase and antimicrobial activities. In addition to the evaluation of these activities, the contents of flavonoids and total phenolic compounds were determined.Antioxidant activity measured by DPPH assay showed that the proanthocyanidin extract exhibited higher antioxidant activity than the aqueous extract. Extract concentration providing 50% inhibition (IC₅₀) ranged from 16.4 ± 6.8 μg/mL to 26.4 ± 6.8 μg/mL. The antioxidant activity was also determined using the β-carotene/linoleic acid bleaching test. The best results (IC₅₀ = 0.11 ± 0.10 mg/mL) were obtained with the proanthocyanidin extract of the plants collected from the desert region (Dhibat).The greatest acetylcholinesterase inhibitory activity (IC₅₀ = 0.23 ± 0.04 mg/mL) was exhibited by the ethyl acetate and methanol extracts of the plants collected from the mountainous region. It seems that extracts obtained with more polar solvents gave better results.The proanthocyanidin extracts showed a good antimicrobial activity against Streptococcus sobrinus at low concentration (MIC = 4 mg/mL). Therefore, these extracts could be used to prevent carious lesions by inhibiting S. sobrinus growth.     

Antioxidant capacity of extract from edible flowers of Prunus mume in China and its active components

Prunus mume flowers are used as traditional edible and medicinal materials in China. In this study, phenolic compounds and antioxidant activity of ethanolic extract from flowers of P. mume in China were investigated for the first time. The total phenol content was estimated as gallic acid equivalents by the Folin-Ciocalteu reagent method. The antioxidant activity was measured by DPPH, ABTS⁺, and OH free radicals scavenging and ferric-reducing antioxidant power (FRAP). Three chlorogenic acid isomers, namely, 3-O-caffeoylquinic, 4-O-caffeoylquinic and 5-O-caffeoylquinic acids, were isolated and purified by preparative HPLC from the ethanolic extract and identified by UV, MS and NMR. The contents of these isolated compounds were quantified by HPLC. Results showed that 5-O-caffeoylquinic acid was of the highest level in these three isomers. The ethanolic extract demonstrated activity to some degree in all the antioxidant assays. In all tested assays, all of the isolated chlorogenic acid isomers exhibited strong antioxidant activities, which were almost the same. The results showed that chlorogenic acid isomers are the key phenolic compounds which are responsible for antioxidant activity of the ethanolic extract from Chinese P. mume flowers.     

Characterisation of cell wall polysaccharide profiles of apricots (Prunus armeniaca L.), peaches (Prunus persica L.), and pumpkins (Cucurbita sp.) for the evaluation of fruit product authenticity

Cell wall polysaccharides were investigated for their suitability as markers for quality and authenticity control of fruit products. For this purpose, the alcohol-insoluble residue (AIR) from several cultivars of apricots and peaches of different harvest seasons, provenances, and stages of ripeness was extracted and subsequently fractionated into acid- and EDTA/alkali-soluble pectins, hemicellulose, and cellulose. Each fraction was analysed for its neutral sugar composition by gas chromatography. In addition, analyses were also carried out on several cultivars of pumpkins because of their potential for use in fraudulent admixtures. Within the respective fruit species, characteristic neutral sugar profiles of the AIR and its fractions were observed, which were found to be independent of the cultivar, harvest season, and provenance. The fruit specific saccharide composition may be used for the differentiation of fruit products devoid of carbohydrate-based hydrocolloids. Furthermore, the isolated hemicellulose may also allow the detection of admixtures of non-specified fruit in complex fruit products, such as jams, spreads, and fruit preparations.     

Characteristics of Prunus serotina seed oil

Oils from Prunus serotina raw and toasted seeds extracted with hexane and supercritical CO₂ were evaluated for their physicochemical characteristics. Supercritical CO₂ extracted the least oil (21.3%), with high absorbing carotenoid pigments. P. serotina oil had characteristically high refractive index and density with three typical absorbance peaks in the UVC (100–290 nm) range centred at 260, 270 and 280 nm. The oil was highly polyunsaturated and abundant in oleic (35%), α-elostearic (27%), linoleic (27%), palmitic (4%), stearic (4%) and β-elostearic (1%) acids. P. serotina seed oil exhibited at least three distinct thermal structural transitions between −35 and −13 °C with two reversing transitions between −19 and −12 °C. Thermal oxidation by differential scanning calorimetry (DSC) revealed a three step oxidation of P. serotina seed oil with the mean onset and oxidation temperatures at 121 and 130–273 °C, respectively, depending on processing. Supercritical CO₂ extraction and toasting significantly affected the thermal and oxidation characteristics, fluorescence, and fatty acids of oils.     

Predation by Blattisocius tarsalis (Berlese) (Acari: Ascidae) on eggs of Ephestia kuehniella Zeller (Lepidoptera: Pyralidae)

The mean predation rate of female B. tarsalis on eggs of E. kuehniella was determined at 15°C, 21°C, and 27°C with prey densities of 3, 5, 10 and 15 eggs. Young eggs less than 24 h old were used as prey. Under all experimental conditions most eggs were only partially consumed, confirming the general theory that predatory mites leave most of the food content unutilized. A mean predation rate of 2.2-7.0 eggs destroyed in 24 h was found, reflecting that a large proportion of the available prey was destroyed. The result supports the view that the predatory mite B. tarsalis could be a relevant biological control agent against E. kuehniella in flour mills. It was further demonstrated that frozen moth eggs can be considered as an appropriate food source.