Wild Mediterranean plants as traditional food: a valuable source of antioxidants

Some wild Mediterranean plants used as traditional food are an extraordinary source of antioxidants. We tested some properties of 10 of these herbaceous plants, used in Liguria (Northwest Italy) to prepare a traditional dish known as "prebuggiun." A total of 9 of them were found to have a polyphenol content and antioxidant properties similar or better than those of red chicory and blueberry, which are, in the case of vegetables and fruits, among the richest of antioxidants. Practical Application: In this article, we reported a study on wild plants growing in the Mediterranean area. These herbs have been neglected and this study aimed to revalue these plants because they are an extraordinary source of antioxidants. The increasing demand for natural antioxidants (additives in the food industry too) justifies the search for new sources of natural antioxidants. The revaluation of these plants will be interesting for: (1) consumer health, rediscovering a vegetable source of high antioxidant power; (2) possibility of producing new commercial products, such as food supplements of high quality and low cost; (3) pharmacological applications.     

Free radical scavenging and cytoprotective activities of phenolic antioxidants

The free radical scavenging activities of three flavonoids (quercetin, rutin and catechin) and four hydroxycinnamic acids (caffeic, ferulic, sinapic, and chlorogenic acids) were evaluated using both oxygen radical absorbance capacity (ORAC) and lipid peroxidation inhibition capacity (LPIC) assays. The cytoprotective effects of these compounds were also measured by the degree of protection against H(2)O(2)-induced damage of human Jurkat cells. All compounds exhibited protection against H(2)O(2)-mediated cytotoxicity in a dose-dependent manner. The concentrations required to result in a 50% reduction in cell death (EC(50) value) were calculated from their dose-response curves. These ranged from 0.15-2.65 microM. Overall, the four hydroxycinnamic acids tested were less effective than the three flavonoids, and of all compounds tested, quercetin offered the strongest protection against H(2)O(2)-induced cell death. A comparison of the results showed that the ability to inhibit peroxidation of lipids in a liposomal system (LPIC) correlated well with the cytoprotective activities (EC(50)), but not with the ability to protect an aqueous fluorescent substrate in the ORAC assays. The results suggest that the behavior of antioxidants in a liposomal membrane is to some extent similar to the mechanism involved in the protection of living cells from oxidative damage.     

Ice cream supplemented with grape juice residue as a source of antioxidants

Grape juice residue was incorporated into ice cream at 2.5%, 5.0% and 10.0% to obtain a product with functional characteristics. The chemical composition, colour, total phenolic compounds, antioxidant capacity and sensory acceptance of the ice creams were analysed at day 0 and after 40 days of storage. Ice creams containing grape juice residue had a higher concentration of phenolic compounds and antioxidant activity compared to the control samples. Consumers’ acceptance was similar for all products. At the end of storage, the polyphenol content and antioxidant activity had decreased. Grape juice residue has potential as a natural source of antioxidants to develop new products.     

Antioxidant and antiradical properties of cranberry juice and extracts

The antioxidant capacities of cranberry juice and three extracts isolated from frozen cranberries containing anthocyanins, water-soluble and apolar phenolic compounds, were evaluated at pH 2.5 and 7, respectively. The free radical-scavenging (FRS) and the lipid peroxidation inhibition (LPI) activities of each samples, and extracts, were studied using the N,N-diethyl-p-phenylenediamine (DPD) decoloration test and the thiobarbituric acid reactive substances (TBARS) assay, respectively. The cranberry phenols displayed good free radical-scavenging properties, but were less efficient at inhibiting the peroxidation of lipids. Of all the samples tested, the water-soluble phenolic compounds showed the greatest free radical-scavenging (68.2 mmol TE/mg phenol) and antioxidant (13.4 mmol TE phenol) activities. The polarity of the phenols, the pH of the medium and the juice process had a great influence on the antioxidant activities. The phenols isolated from cranberries with an aqueous solvent have greater antioxidant properties than those extracted with an organic solvent mixture. The antioxidant activity of the cranberry samples adjusted at pH 2.5 was greater than those adjusted at pH 7. Compared to the cranberry extracts, the juice exhibited a much lower antioxidant activity, especially when compared with the extract containing water-soluble compounds which the extraction conditions were similar to those used to obtain the juice.     

From famine plants to tasty and fragrant spices: Three Lamiaceae of general dietary relevance in traditional cuisine of Trás-os-Montes (Portugal)

The chemical composition and nutritional value of three Lamiaceae often used as spices in Portuguese traditional cuisine: Ground ivy (Glechoma hederaceae L.), oregano (Origanum vulgare subsp. virens (Hoffmanns. & Link) Ietswaart) and mastic thyme (Thymus mastichina L.) were determined. Chemical composition evaluation included moisture, total fat content, crude protein, ash, carbohydrates, and nutritional value determination. The macronutrient profile revealed that these spices are rich sources of carbohydrates and that an edible portion of 100 g assures, on average, 161 Kcal. The composition in individual sugars was determined by high performance liquid chromatography coupled to a refraction index detector (HPLC/RID), being this methodology completely validated. All the compounds were separated in a period of time of 15 min; the method used proved to be sensitive, reproducible and accurate. Fructose, glucose, sucrose and raffinose were the most abundant sugars. The analysis of fatty acid composition, performed by gas chromatography coupled to a flame ionization detector (GC/FID), allowed the quantification of twenty two fatty acids. Polyunsaturated fatty acids and, in particular, α-linolenic and linoleic acids, were predominant.     

Antioxidant capacity and angiotensin I converting enzyme inhibitory activity of a melon concentrate rich in superoxide dismutase

Antioxidant capacity and angiotensin 1-converting enzyme (ACE) inhibitory activity of a melon concentrate rich in superoxide dismutase (SOD-MC) were investigated in vitro. The total antioxidant capacity (TAC) was measured by the Trolox equivalent antioxidant capacity assay (TEAC), the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical assay, and the ferric reducing antioxidant power assay (FRAP). The ability of the extract to scavenge three specific reactive oxygen species (superoxide radical anion (O(2)(-)), hydroxyl radical (HO()) and hydrogen peroxide (H(2)O(2))) was also investigated in order to better evaluate its antioxidant properties. Even if the measures of TAC were relatively low, results clearly established an antioxidant potential of SOD-MC that exhibited the highest radical-scavenging activity towards O(2)(-), with a IC(50) 12-fold lower than that of H(2)O(2) or HO(). This lets hypothesis that the antioxidant potential of SOD-MC could be mainly due to its high level of SOD. Moreover, for the first time, an ACE inhibitory activity of SOD-MC (IC(50)=2.4±0.1mg/mL) was demonstrated, showing that its use as a functional food ingredient with potential preventive benefits in the context of hypertension may have important public health implications and should be carefully considered.     

St. John’s Wort (Hypericum perforatum) extracts and isolated phenolic compounds are effective antioxidants in several in vitro models of oxidative stress

The antioxidant potential of a total ethanolic extract of Hypericum perforatum (TE) was assessed, and correlated with the phenolic composition. TE was fully characterized by HPLC-DAD and HPLC-MSn, and phenolic compounds were isolated by semi-preparative HPLC. The free radical-scavenging properties of the TE were studied using DPPH (EC₅₀ = 49 μg dwb/ml), AAPH (EC₅₀ = 50 μg dwb/ml) and the antioxidant potential was evaluated using lipid peroxidation induced by ascorbate/iron (EC₅₀ = 28 μg dwb/ml). Moreover, the TE was able to scavenge NO (by using sodium nitroprusside) and HOCl (by evaluating TNB reduction). Furthermore, the antioxidant potentials of the isolated compounds were evaluated and several compounds, namely flavonoids, were significantly less effective at DPPH- and AAPH-scavenging, compared to their ability to prevent iron-mediated lipid peroxidation. Therefore, TE was able to scavenge several free radicals, indicating beneficial cellular protection against oxidative stress.     

Thermo-induced lipid oxidation of a culinary oil: The effect of materials used in common food processing on the evolution of oxidised species

The effect of materials commonly employed in domestic food processing was investigated in vegetable oil undergoing episodes of thermal stress (180 °C). ¹H NMR spectroscopy was employed to follow the evolution of lipid peroxidation products, notably hydroperoxides and aldehydes. In samples containing copper foils, EPR spectroscopy was employed to investigate the nature of dissolved Cu(II) ions, which are known to be responsible for the decomposition of hydroperoxides. DFT calculations were used to support possible structures of Cu(II) oxo complexes.     

Grape skin extracts as a sustainable source of antioxidants in an oil-in-water emulsion: an alternate natural approach to synthetic antioxidants using principal component analysis

Grape (Kyoho) skin, used to retard lipid oxidation in edible oil foods, was investigated to reduce lipid oxidation in an oil-in-water (O/W) emulsion during 20 day of storage. The antioxidant efficacy of Kyoho skin extracts in O/W emulsions was determined by the measurement of secondary oxidation products. Moreover, principal component analysis (PCA) was conducted to determine similarities between emulsions treated with or without Kyoho skin extracts and standards. The data revealed that Kyoho skin extracts exhibited >93% inhibition and reported a similar p-anisidine (4.30–20.71) and TBARS (6.08–11.15 mg MDA L⁻¹) values over the standards during 20 day of storage. PCA (PCs 1 (51.83%) and 2 (18.85%)) demonstrated a similarity in the contribution of Kyoho skin extracts over the synthetic antioxidants in O/W emulsion. Overall, these findings highlighted the possibility of using Kyoho skin extracts as natural antioxidants to decrease oxidative rancidity in foods.     

Pressure and temperature stability of water-soluble antioxidants in orange and carrot juice: a kinetic study

The stability of water-soluble antioxidant in orange and carrot juice was studied on a kinetic basis during thermal (75–120 °C) and high pressure (100–800 MPa; 30–65 °C) treatments. The water soluble antioxidant capacities of both orange and carrot juice, determined using the TEAC number, increased for the first 60 min and 90 min of thermal treatment respectively. These increases can be described by a first order reaction model. The increases in antioxidant capacity became sharper as the temperature was increased, and the estimated Ea values were 79.00±7.83 and 40.46±8.43 kJ mol^–1 respectively for orange and carrot juice.During the high pressure treatments, a decrease in TEAC number was noticed for the antioxidant capacity of orange juice, and an increase in TEAC number for carrot juice. A first order reaction model was applied to estimate the rate constants. At all of the temperatures studied, the antioxidant capacity of orange juice decreased more quickly as the pressure was increased. On the other hand, the increase in the antioxidant capacity of carrot juice was slowed down by a pressure increase at temperatures above 40 °C.     

Monomeric phenolics in different parts of high‐acid apple (Malus sieversii f. niedzwetzkyana (Dieck) Langenf): a promising source of antioxidants for application in nutraceuticals

The high‐acid apple (Malus sieversii f. niedzwetzkyana (Dieck) Langenf) possessing deep red peel and light red flesh is widely distributed in China. To determine if a useful apple variety is being ignored, the monomeric phenolic profiles and antioxidant activities of peel, flesh, pomace, whole fruit and juice were evaluated. The results were compared to those of ‘Fuji’ and ‘Granny Smith’ apples. The high‐acid apple possessing the highest total phenolic and anthocyanin contents among three apple varieties contained the most chlorogenic acid, phloridzin, epicatechin, ferulic acid, catechin, vanillic acid, p‐coumaric acid and caffeic acid. The extraction yields of phenolics (64%) and anthocyanins (89%) from the high‐acid apple to juice were the highest. The high‐acid apple possessing the greatest antioxidant activity had the strongest antihaemolysis activity, indicating that it could be used to produce juice and value‐added ingredient to assist in the prevention of chronic disease.     

Antioxidant properties of Prangos ferulacea (L.) Lindl., Chaerophyllum macropodum Boiss. and Heracleum persicum Desf. from Apiaceae family used as food in Eastern Anatolia and their inhibitory effects on glutathione-S-transferase

Therapeutic effects of several medicinal plants and vegetables, which are commonly used as food and in folk medicine against many disease, are well known. Antioxidant capacities of Heracleum persicum Desf., Prangos ferulacea (L.) Lindl., Chaerophyllum macropodum Boiss. species from Apiaceae family were evaluated by determining their effects on DPPH radical scavenging, and lipid peroxidation inhibition, as well as their total phenolic contents. Potential natural glutathione-S-transferase inhibitors have gained great importance in the last decade especially because of the role of glutathione-S-transferases in developing resistance to chemotherapy. Selected plants were therefore further investigated for their influence on the activity of glutathione-S-transferase enzyme.     

Nitrite and nitrate in fresh meats: a contribution to the estimation of admissible maximum limits to introduce in directive 95/2/EC

Nitrite and nitrate are food preservatives not allowed in fresh meat preparations. Two hundred fresh meat samples were analysed to evaluate the natural presence of nitrite and nitrate and estimate the maximum concentrations to considerate as ‘natural’ and to admit in fresh meat preparations. The analyses were carried out by a validated ion chromatography method, and the ‘positive’ samples were confirmed by an alternative ion chromatography method. Nitrite residues were not detected. Quantifiable nitrate concentrations, ranging from 10.2 to 36.5 mg kg^?1, were found in nineteen samples. In chicken meat samples, nitrate residues were not detected. Taking into account the distribution of nitrate concentrations, it is possible to suggest a maximum admissible limit of 30.0 mg kg^?1 in beef and pork meats; in equine meats, this limit may be increased to 40.0 mg kg^?1. Below these values, the samples can be considered as ‘compliant’.     

Effect of lyophilized water extracts of Melissa officinalis on the stability of algae and linseed oil-in-water emulsion to be used as a functional ingredient in meat products

Previous work pointed out the possibility to enhance the nutritional value of meat products using long chain ω − 3 PUFA enriched emulsions. Oil-in-water emulsions elaborated with a mixture of algae and linseed oils (15:10) in order to be used as functional ingredient were stabilized with BHA (butylhydroxyanisol) or with a lyophilized water extract of Melissa officinalis L. (Lemon balm). The lipid profile of the oil mixture showed a high amount of DHA (31.7%), oleic (25.4%) and α-linolenic acid (12.7%) resulting in a very low ω − 6/ω − 3 ratio (0.12). The lyophilized extract of M. officinalis showed a high antioxidant activity (being 62 ppm of the lyophilized water extract of Melissa equivalent to 200 ppm of BHA, using the DPPH assay as reference), and high total phenolic content. Studying the oxidation process in the emulsions during 15 days at room temperature, it could be concluded that this extract was as efficient as BHA in order to control the thiobarbituric acid reactive substances (TBARS) formation.     

发酵果蔬的功能及应用现状

随着消费者对健康饮食的日益重视,具有保健作用的发酵果蔬汁相关产品引起了研究者的广泛关注。果蔬是微生物生长的理想基质,果蔬汁发酵后会产生丰富的营养物质和多种功能活性,因此实现了果蔬高值化利用,使得未来发酵果蔬汁系列产品有着广阔的应用市场。本文综述了果蔬汁的常见发酵方式,发酵后的生物活性成分、功能活性以及发酵对果蔬汁的品质改善作用,对发酵果蔬汁行业的发展具有一定的指导意义。     

Potato peel extract as a natural antioxidant in chilled storage of minced horse mackerel (Trachurus trachurus): Effect on lipid and protein oxidation

The present work was undertaken to examine the utilisation of potato peel, a waste material, as a source of natural antioxidants for retarding lipid and protein oxidation in minced mackerel. Mackerel mince with two different concentrations (2.4 or 4.8 g/kg) of water or ethanol extracts of potato peel and a control with no added extracts were prepared. The samples were stored at 5 °C for 96 h and the sampling was done at time points 0, 24, 48 and 96 h. The ethanol extracts, which contained high amounts of phenolic compounds, was found to be very effective in retarding lipid and protein oxidation as it resulted in low levels of peroxide value, volatiles, carbonyl compounds and protected against the loss of α-tocopherol and tryptophan and tyrosine residues. Water extracts was less efficient especially at higher concentrations, which might be due to lower phenolic content or due to the pro-oxidative nature of some of the phenolic acids/co-extracted compounds.