Antioxidative enzyme activity and internal browning of 1‐methylcyclopropene‐treated European pear fruits (cv. ‘Shahmiveh’ and ‘Sebri’)

The effects of 1‐methylcyclopropene (1‐MCP) on antioxidative enzyme and internal browning (IB) incidence of two European pear cultivars ‘Shahmiveh’ and ‘Sebri’ stored at 0.5 °C were investigated. Ethylene production of ‘Sebri’ was delayed by 1‐MCP but suppressed in ‘Shahmiveh’. IB increased in both cultivars, with a higher level of the incidence in ‘Shahmiveh’, and was reduced by 1‐MCP. Activities of catalase (CAT) and peroxidase, but not superoxide dismutase (SOD), decreased in untreated fruit during the first 40 days. 1‐MCP had little effect on SOD activity or on total phenolics. Polyphenoloxidase activity did not increase over time in 1‐MCP‐treated fruit of the IB sensitive ‘Shahmiveh’, and the effect was inconsistent for ‘Sebri’. Ascorbic acid (AA) levels in 1‐MCP‐treated fruit of both cultivars declined at a lower rate compared with untreated fruit during storage, but the reduction in AA levels was faster in ‘Shahmiveh’ compared with ‘Sebri’. Also, the effects of 1‐MCP on antioxidative systems may be related to IB development.     

Enzymatic Synthesis of Refined Olive Oil‐Based Structured Lipid Containing Omega ‐3 and ‐6 Fatty Acids for Potential Application in Infant Formula

Structured lipids (SLs) containing palmitic, docosahexaenoic (DHA), and gamma‐linolenic (GLA) acids were produced using refined olive oil, tripalmitin, and ethyl esters of DHA single cell oil and GLA ethyl esters. Immobilized Lipozyme TL IM lipase was used as the biocatalyst. The SLs were characterized for fatty acid profile, triacylglycerol (TAG) molecular species, solid fat content, oxidative stability index, and melting and crystallization profiles and compared to physical blend of substrates, extracted fat from commercial infant formula (IFF), and milk fat. 49.28 mol% of palmitic acid was found at the sn‐2 position of SL TAG and total DHA and GLA composition were 0.73 and 5.00 mol%, respectively. The total oleic acid content was 36.13 mol% which was very close to the 30.49% present in commercial IFF. Comparable solid fat content profiles were also found between SLs and IFF. The SLs produced have potential for use in infant formulas.     

Hypolipidemic Activity of Peony Seed Oil Rich in α‐Linolenic,is Mediated Through Inhibition of Lipogenesis and Upregulation of Fatty Acid β‐Oxidation

Peony seed oil (PSO) is a new resource food rich in α‐Linolenic Acid(ALA) (38.66%). The objective of this study was to assess the modulatory effect of PSO on lipid metabolism. Lard oil, safflower oil (SFO), and PSO were fed to wistar rats with 1% cholesterol in the diet for 60 d. Serum and liver lipids showed significant decrease in total cholesterol (TC), triglyceride (TG), and low density lipoprotein‐cholesterol (LDL‐C) levels in PSO fed rats compared to lard oil and SFO fed rats. ALA, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), contents were significantly increased, whereas linoleic acid (LA), arachidonic acid (AA) levels decreased in serum and liver of PSO fed rats. Feeding PSO increased ALA level and decreased n‐6 to n‐3 polyunsaturated fatty acid (PUFA) ratio. The hypolipidemic result of PSO indicated that PSO participated in the regulation of plasma lipid concentration and cholesterol metabolism in liver. The decreased expression of sterol regulatory element‐binding proteins 1C (SREBP‐1c), acetyl‐CoA carboxylase (ACC), and fatty acid synthase (FAS)‐reduced lipid synthesis; Activation of peroxisome proliferator–activator receptor (PPARα) accompanied by increase of uncoupling protein2 (UP2) and acyl‐CoA oxidase (AOX) stimulated lipid metabolism and exerted an antiobesity effect via increasing energy expenditure for prevention of obesity.     

Original article: The effect of freezing at −18 °C and −70 °C with and without ascorbic acid on the stability of antioxidant in extracts of apple and orange fruits

The influence of low temperature and storage time on the antioxidant capacity of standard solutions and apple and orange extracts was evaluated. In addition, the effects of ascorbic acid (AA) addition to the fruit extracts in terms of antioxidant capacity, AA content and soluble and hydrolyzable polyphenol contents were also analysed. Polyphenol contents in both apple and orange extracts were stable during storage period, which reflected also in the antioxidant capacity stability. Freezing at ?18 °C did not result in different retention rates for polyphenols, AA and antioxidant capacity when compared to freezing at ?70 °C. However, vitamin C content in orange juice, without AA addition, slightly increased along the experimental period (10 days). Thus, this study shows that it may not be necessary to measure the antioxidant capacity immediately after the preparation of fruit extracts or antioxidant standard solutions.     

α‐Eleostearic acid is more effectively metabolized into conjugated linoleic acid than punicic acid in mice

BACKGROUND: The objective of this study was to investigate the metabolism of α‐eleostearic acid (α‐ESA, cis9,trans11,trans13‐18:3) and punicic acid (PA, cis9,trans11,cis13‐18:3) and to compare the relative conversion efficiency of these fatty acids into conjugated linoleic acids (CLAs) in mice. RESULTS: Twenty‐four male ICR mice were fed either a control diet or one of two experimental diets supplemented with 10 g kg^?1α‐ESA or PA in the form of triacylglycerols for 6 weeks. The accumulation of PA in all tissues examined was significantly higher than α‐ESA; in both groups it was found that cis9,trans11‐conjugated linoleic acid (cis9,trans11‐18:2) was detected in all tissues examined. The relative conversion rate of α‐ESA into cis9,trans11‐18:2 was significantly higher than that of PA. The highest conversion rate of α‐ESA was found in adipose tissue (91.8%), spleen (91.4%) and kidney (90.7%), and the lowest in the heart (84.6%). The highest conversion rate of PA occurred in the liver (76.2%) and the lowest occurred in the heart (54.5%). CONCLUSION: The present results indicate that both α‐ESA and PA are effectively metabolized into cis9,trans11‐18:2 in mice. These conjugated dietary fatty acids might be useful sources of CLAs in tissues owing to the natural abundance of α‐ESA and PA in some seeds. Copyright © 2009 Society of Chemical Industry     

Improved physical stability of docosahexaenoic acid and eicosapentaenoic acid encapsulated using nanoliposome containing α‐tocopherol

This study aimed to develop a nanoliposomal formulation containing α‐tocopherol loaded with eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and to characterise the formulation by its physical stability. For this purpose, different nanoliposomal formulations with dipalmitoyl phosphocholine were prepared using a modified thin‐film hydration method and evaluated by particle size, polydispersity index (PDI), transmission electron microscopy, differential scanning calorimetry and determining the encapsulation efficiencies of DHA and EPA. A physical stability study was conducted by investigating the change in the vesicle encapsulation efficiency, particle size, PDI and shape when stored at 4, 30 and 40 °C for 3 months. High encapsulation efficiency of DHA and EPA (89.1% ± 0.6% and 81.9% ± 1.4%) and appropriate particle size (82 ± 0.8 nm) were obtained for liposomes composed of α‐tocopherol. The optimum formulation was stable for 90 days when kept at 4 °C. This study demonstrated that α‐tocopherol had a protective effect on the physical stability of the nanoliposomes containing DHA and EPA.     

Concentration‐dependent antioxidant activities of conjugated linoleic acid and α‐tocopherol in corn oil

BACKGROUND: Antioxidants prevent rancidity (lipid peroxidation) and natural antioxidants, e.g., α‐tocopherol, likely provide additional value to oil‐based food products because of their health benefits. Conjugated linoleic acid (CLA) has potential health benefits and may exhibit antioxidant properties. The main aim of this study was to compare the antioxidant efficacy of α‐tocopherol, trans‐10, cis‐12‐CLA and cis‐9, trans‐11‐CLA (in graded concentrations) added to antioxidant‐stripped corn oil. RESULTS: As compared to α‐tocopherol, both CLA isomers displayed significant inhibition of corn oil lipid peroxidation induced by copper. Inhibition of thiobarbituric acid reactive substances (TBARS) were CLA concentration dependent for both isomers but with significant inhibition occurring at 0.1 and 1 ppm of CLA isomers or α‐tocopherol, respectively (P < 0.05). Graded concentrations of α‐tocopherol, and for both CLA isomers and time, had significant effects on TBARS formation (P < 0.0001). There were significant effects in interactions between graded concentrations and time for both CLA isomers (P < 0.0001) but not for α‐tocopherol (P > 0.05). CONCLUSION: CLA compounds could serve as useful food antioxidants and provide additional value because of their potential bioactivity in disease prevention. Copyright © 2007 Society of Chemical Industry     

18β‐Glycyrrhetinic acid: its core biological properties and dermatological applications

Recently, attention has been focused on identifying natural herbal compounds with high biological activity, especially antioxidative, anti‐inflammatory and antimicrobial properties, for preventing and controlling various skin conditions, including inflammation‐related diseases such as atopic dermatitis and UV‐induced skin photoaging. One key active plant ingredient is 18β‐glycyrrhetinic acid (GA), the main metabolite of glycyrrhizin (GL), obtained from licorice root. The review examines the valuable biological properties of GA, particularly those playing key roles in the treatment of various dermatological disorders in humans. The review highlights the key anti‐inflammatory, antioxidant and antimicrobial properties of GA and its toxicity towards normal cells lines. It also examines the physicochemical properties of GA and presents methods of increasing its penetration through the stratum corneum and bioaccumulation with the use of modern delivery systems such as liposomes and nanoemulsions.     

Studies of IAA and IBA as fungal α‐amylase inhibitors using enzyme kinetics,molecular modeling and thermodynamics

Simple sugars like glucose and maltose are found to induce the production of aflatoxin. Since the formation of simple sugars is directly linked to α‐amylase function in fungus, it is considered that the inhibition of this enzyme is an effective approach to control the production of aflatoxins. The action of two indole derivatives such as indoleacetic acid (IAA) and indolebutyric acid (IBA) has been investigated by means of enzyme kinetics, isothermal titration calorimetric and molecular docking analysis. The results suggested that both IAA and IBA can inhibit α‐amylase in a competitive manner.     

Regioisomeric distribution of 9‐ and 13‐hydroperoxy linoleic acid in vegetable oils during storage and heating

BACKGROUND

The oxidative deterioration of vegetable oils is commonly measured by the peroxide value, thereby not considering the contribution of individual lipid hydroperoxide isomers, which might have different bioactive effects. Thus, the formation of 9‐ and 13‐hydroperoxy octadecadienoic acid (9‐HpODE and 13‐ HpODE), was quantified after short‐term heating and conditions representative of long‐term domestic storage in samples of linoleic acid, canola, sunflower and soybean oil, by means of stable isotope dilution analysis–liquid chromatography‐mass spectroscopy.

RESULTS

Although heating of pure linoleic acid at 180 °C for 30 min led to an almost complete loss of 9‐HpODE and 13‐HpODE, heating of canola, sunflower and soybean oil resulted in the formation of 5.74 ± 3.32, 2.00 ± 1.09, 16.0 ± 2.44 mmol L^–1 13‐HpODE and 13.8 ± 8.21, 10.0 ± 6.74 and 45.2 ± 6.23 mmol L^–1 9‐HpODE. An almost equimolar distribution of the 9‐ and 13‐HpODE was obtained during household‐representative storage conditions after 56 days, whereas, under heating conditions, an approximately 2.4‐, 2.8‐ and 5.0‐fold (P ≤ 0.001) higher concentration of 9‐HpODE than 13‐HpODE was detected in canola, soybean and sunflower oil, respectively.

CONCLUSION

A temperature‐dependent distribution of HpODE regioisomers could be shown in vegetable oils, suggesting their application as markers of lipid oxidation in oils used for short‐term heating. © 2017 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

SIMULTANEOUS DETERMINATION OF α, β AND ISO-α ACIDS IN HOPS AND HOP PRODUCTS

A method for the simultaneous analysis of α, β and iso-α acid in hops, hop extracts and isomerised hop extracts is described. It is based on the use of reversed phase high performance liquid chromatography and quantitative evaluation of the hop compounds is carried out with a computing integrator. The isomerisation reaction can be examined in detail, particularly in connection with the production of hop derived haze forming compounds in isomerised hop extracts used for post fermentation bittering.     

Direct and indirect antioxidant properties of α‐lipoic acid and therapeutic potential

Diabetes has emerged as a major threat to worldwide health. The exact mechanisms underlying the disease are unknown; however, there is growing evidence that the excess generation of reactive oxygen species (ROS) associated with hyperglycemia, causes oxidative stress in a variety of tissues. In this context, various natural compounds with pleiotropic actions like α‐lipoic acid (LA) are of interest, especially in metabolic diseases such as diabetes. LA, either as a dietary supplement or a therapeutic agent, modulates redox potential because of its ability to match the redox status between different subcellular compartments as well as extracellularly. Both the oxidized (disulfide) and reduced (di‐thiol: dihydro‐lipoic acid, DHLA) forms of LA show antioxidant properties. LA exerts antioxidant effects in biological systems through ROS quenching but also via an action on transition metal chelation. Dietary supplementation with LA has been successfully employed in a variety of in vivo models of disease associated with an imbalance of redox status: diabetes and cardiovascular diseases. The complex and intimate association between increased oxidative stress and increased inflammation in related disorders such as diabetes, makes it difficult to establish the temporal sequence of the relationship.     

Structural characterisation of β‐cyclodextrin crosslinked by adipic acid

This study was conducted to investigate the structural characterisation of β‐cyclodextrin (β‐CD) crosslinked by adipic acid. β‐CD was treated with different concentrations (0%, 5%, 10% and 15%, w/v) of adipic acid. Different instruments, such as scanning electron microsope (SEM), Fourier‐transform infrared (FT‐IR) spectroscopy and ¹H and ¹³C nuclear magnetic resonance (NMR) spectra were used to find out chemical structure in the crosslinked β‐CD. SEM analysis suggested that crosslinking β‐CD with 15% adipic acid changed the original morphology and considerably increased the particle size of the raw material. FT‐IR spectroscopy data showed that an intensive absorption band at 1706 cm^?1 was present in the β‐CD samples treated with 10% and 15% adipic acid, indicating a crosslinking between hydroxyl groups of β‐CD and carboxyl groups of adipic acid. NMR spectra revealed that the ester linkages between hydroxyl groups of β‐CD and carboxyl groups of adipic acid were formed after crosslinking of β‐CD with adipic acid.     

Phenolic diterpene and α‐tocopherol contents in leaf extracts of 60 Salvia species

BACKGROUND: Carnosic acid and carnosol, the two major phenolic diterpenes present in rosemary and sage extracts, have received attention in food science and biomedicine because of their potent antioxidant properties. In plants, these compounds have been identified as being present in some species of the family Lamiaceae, but there is still little information about their distribution within the plant kingdom. The aim of the present study was to gain a better understanding of the occurrence of these compounds within leaf extracts of the genus Salvia and also to examine to what extent leaf senescence may influence their accumulation in relation to that of α‐tocopherol (vitamin E). RESULTS: Methanolic leaf extracts of 60 species of the genus Salvia were tested for the presence of carnosic acid and carnosol. These two diterpenes were detected in 48 and 27 species respectively. In contrast, α‐tocopherol was present in all species examined. Leaf senescence in Salvia officinalis resulted in α‐tocopherol increases by up to 5.5‐fold, while carnosic acid and carnosol increased by up to 18 and 290% respectively. Isorosmanol, an oxidation product of carnosic acid, increased by up to 2.1‐fold in senescing leaves. CONCLUSION: It was found that, while α‐tocopherol is ubiquitous in the genus Salvia, phenolic diterpenes are present in several but not all species. It was also shown that leaf senescence may increase the yield of both phenolic diterpenes and α‐tocopherol in sage extracts. Copyright © 2008 Society of Chemical Industry