Inhibition of Clotrimazole-resistant Candida albicans by plants used in Iranian folkloric medicine

In vitro anticandidal activity of methanol extracts of 42 plant species of 29 families used in Iranian folkloric medicine were evaluated at 20 mg/ml concentration against Clotrimazole-resistant Candida albicans. Nineteen plant species in 16 families showed anticandidal activities. The lowest MIC of 0.62 mg/ml belonged to Terminalia chebula and Thymus vulgaris.     

Measuring antioxidant effectiveness in food

Many new in vitro methods have been developed to evaluate antioxidant activity. Unfortunately, these in vitro methods often correlate poorly with the ability of compounds to inhibit oxidative deterioration of foods because the in vitro assays do not account for factors such as the physical location of the antioxidant, its interaction with other food components, and environmental conditions. To accurately evaluate the potential of antioxidants in foods, models must be developed that have the chemical, physical, and environmental conditions expected in food products. This paper outlines model systems of the evaluation of antioxidants in three types of foods: bulk oil, oil-in-water emulsions, and muscle foods. These model systems are not intended to be inclusive of all possible methods to measure lipid oxidation and antioxidant activity. However, use of these models would allow researchers to more easily compare research results from one paper to another.     

Effect of enzymatic randomization on positional distribution and stability of seal blubber and menhaden oils

In an effort to investigate the effect of positional distribution on oxidative stability of menhaden and seal blubber oils, Novozyme 435 was used as a random biocatalyst. Positional distribution of fatty acids was determined using gas chromatography. As some of the α-tocopherol was lost during randomization, its content was adjusted to the level prior to the process to eliminate this effect on oxidative stability of oils tested. Conjugated dienes (CD) and thiobarbituric acid reactive substances (TBARS) were used as indicators of oxidative stability. The results showed that the polyunsaturated fatty acids were distributed predominantly at terminal positions in randomized menhaden oil, whereas they were distributed more evenly among all positions in enzymatically randomized seal blubber oil, compared to their unrandomized counterparts. Results of CD and TBARS values indicated that randomized menhaden oil was more stable than the original oil, whereas randomized seal blubber oil was more vulnerable to oxidation compared to its counterpart. Changes of oxidative stability after randomization were mainly due to positional redistribution of fatty acids, especially those of the polyunsaturated types.     

Comparison of antioxidant activity, anthocyanins, carotenoids, and phenolics of three native fresh and sun-dried date (Phoenix dactylifera L.) varieties grown in Oman

Fresh and sun-dried dates of three native varieties from Oman, namely, Fard, Khasab, and Khalas, were examined for their antioxidant activity and total contents of anthocyanins, carotenoids, and phenolics, as well as free and bound phenolic acids. All results are expressed as mean value +/- standard deviation (n = 3) on a fresh weight basis. Fresh date varieties were found to be a good source of antioxidants (11687-20604 micromol of Trolox equiv/g), total contents of anthocyanins (0.24-1.52 mg of cyanidin 3-glucoside equiv/100 g), carotenoids (1.31-3.03 mg/100 g), phenolics (134-280 mg of ferulic acid equiv/100 g), free phenolic acids (2.61-12.27 mg/100 g), and bound phenolic acids (6.84-30.25 mg/100 g). A significant (p < 0.05) amount of antioxidants and carotenoids was lost after sun-drying of dates, whereas the total content of phenolics and free and bound phenolic acids increased significantly (p < 0.05). Anthocyanins were detected only in fresh dates. Date varieties had different levels and patterns of phenolic acids. Four free phenolic acids (protocatechuic acid, vanillic acid, syringic acid, and ferulic acid) and nine bound phenolic acids (gallic acid, protocatechuic acid, p-hydroxybenzoic acid, vanillic acid, caffeic acid, syringic acid, p-coumaric acid, ferulic acid, and o-coumaric acid) were tentatively identified. Of the date varieties studied, Khalas, which is considered to be premium quality, had higher antioxidant activity, total carotenoids, and bound phenolic acids than other varieties. These results suggest that all date varieties serve as a good source of natural antioxidants and could potentially be considered as a functional food or functional food ingredient, although some of their antioxidant constituents are lost during sun-drying.     

Comparative quality assessment of cultured and wild sea bream (Sparus aurata) stored in ice

Comparative quality assessment of cultured and wild sea bream stored in ice for up to 23 days was achieved by the monitoring of sensory quality, levels of nucleotide, nucleotide breakdown products, and texture by a texturometer. The changes in sensory quality of both raw and cooked fish were assessed using the modified Tasmanian and Torry schemes, respectively. K and related values (freshness indicators), namely, K, K(i), G, P, H, and F(r), were calculated. Linear increases (r(2) > or = 0.99) in K, K(i), G, and P (and a decrease in F(r)) values for cultured sea bream and in the H value for wild sea bream with increasing storage periods were observed. The limit for acceptability of cultured and wild sea bream stored in ice was approximately 16-18 days (average K, K(i), G, and P values: approximately 35-40%; H values: approximately 5% for cultured and 10% for wild; and F(r ) values: approximately 65-70%). The texture of cultured and wild sea bream decreased throughout the storage period, and they were not significantly (p > 0.05) different until after day 16 when the wild sea bream was significantly softer than the cultured. The sensory score of both cultured and wild raw fish showed a good relationship with some freshness and texture indicators over the entire storage period (r(2) values > or = 0.99). These indicators were K, K(i), G, P, and F(r) values for cultured and H value for wild fish.     

Chitosan as an edible invisible film for quality preservation of herring and atlantic cod

The effect of chitosan with different molecular weights as coatings for shelf-life extension of fresh fillets of Atlantic cod (Gadus morhua) and herring (Clupea harengus) was evaluated over a 12-day storage at refrigerated temperature (4 +/- 1 degrees C). Three chitosan preparations from snow crab (Chinoecetes opilio) processing wastes, differing in viscosities and molecular weights, were prepared; their apparent viscosities (360, 57, and 14 cP) depended on the deacetylation time (4, 10, and 20 h, respectively) of the chitin precursor. Upon coating with chitosans, a significant (p < or = 0.05) reduction in relative moisture losses of 37, 29, 29, 40, and 32% was observed for cod samples coated with 360 cP chitosan after 4, 6, 8, 10, and 12 days of storage, respectively. Chitosan coating significantly (p < or = 0.05) reduced lipid oxidation as displayed in peroxide value, conjugated dienes, 2-thiobarbituric acid reactive substances and headspace volatiles, chemical spoilage as reflected in total volatile basic nitrogen, trimethylamine, and hypoxanthine, and growth of microorganisms as reflected in total plate count in both fish model systems compared to uncoated samples. The preservative efficacy and the viscosity of chitosan were inter-related; the efficacy of chitosans with viscosities of 57 and 360 cP was superior to that of chitosan with a 14 cP viscosity. Thus, chitosan as edible coating would enhance the quality of seafoods during storage.     

Identification and quantification of low molecular weight phenolic antioxidants in seeds of evening primrose (Oenothera biennis L.)

Crude extracts of evening primrose meal were prepared in 56% (v/v) acetone and separated into six fractions (I-VI) using a Sephadex LH-20 column. Qualitative tests for phenolic and vanillin positive compounds produced positive results for all fractions. Silica gel thin-layer chromatography of fractions III and V allowed the location and isolation of two spots containing moderate to strong antioxidative compounds. High-performance liquid chromatography of the spot isolated from fraction III showed the resolution of two structurally related compounds, whereas that of the spot from fraction V showed the presence of one compound. Nuclear magnetic resonance spectroscopy and electron impact mass spectrometry produced sufficient evidence to identify the isolated compounds as (+)-catechin, (-)-epicatechin, and gallic acid. These compounds accounted for about 10.5 and 1.7% of the dry mass of the crude extracts and meal, respectively.     

Factors affecting grazing preference by sheep in a breeding population of tall fescue (Festuca arundinacea Schreb.)

A disadvantage of tall fescue (Festuca arundinacea Schreb.) is its low voluntary intake, resulting in suboptimal performance under grazing. Ideally, selection for this trait is done using grazing animals, but their use in plant breeding programmes is costly and laborious. Repeatable, stable and quantifiable traits linked to animal preference could ease tall fescue breeding. We established a trial to find relationships between the grazing preference of sheep and sward‐ and plant‐related traits. Seventeen genotypes were studied in swards. Sheep grazing preference, pre‐grazing sward height (SH), leaf softness, leaf blade length, width, colour and shear strength, and concentration of fibre, silica, digestible organic matter (DOM) and water‐soluble carbohydrate (WSC) were quantified throughout the growing season. The traits with the strongest correlation with sheep preference were DOM, SH, leaf colour, leaf width and WSC. Leaf softness, silica content and leaf shear strength were not correlated with sheep preference. We conclude that DOM is the trait that offers the best prospects for contributing to progress in tall fescue plant breeding for both intake and feeding value.     

Importance of insoluble-bound phenolics to antioxidant properties of wheat

Two commercial samples of soft (70% Canadian Eastern soft red spring and 30% Canadian Eastern soft white winter) and hard (90% Canadian western hard red spring and 10% Canadian Eastern hard red winter) wheats were used to obtain different milling fractions. Phenolics extracted belonged to free, soluble esters and insoluble-bound fractions. Soluble esters of phenolics and insoluble-bound phenolics were extracted into diethyl ether after alkaline hydrolysis of samples. The content of phenolics was determined using Folin-Ciocalteu's reagent and expressed as ferulic acid equivalents (FAE). The antioxidant activity of phenolic fractions was evaluated using Trolox equivalent antioxidant capacity, 2,2-diphenyl-1-picrylhydrazyl radical scavenging, reducing power, oxygen radical absorbance capacity, inhibition of oxidation of human low-density lipoprotein cholesterol and DNA, Rancimat, inhibition of photochemilumenescence, and iron(II) chelation activity. The bound phenolic content in the bran fraction was 11.3 +/- 0.13 and 12.2 +/- 0.15 mg FAE/g defatted material for hard and soft wheats, respectively. The corresponding values for flour were 0.33 +/- 0.01 and 0.46 +/- 0.02 mg FAE/g defatted sample. The bound phenolic content of hard and soft whole wheats was 2.1 (+/-0.004 or +/-0.005) mg FAE/g defatted material. The free phenolic content ranged from 0.14 +/- 0.004 to 0.98 +/- 0.05 mg FAE/g defatted milling fractions of hard and soft wheats examined. The contribution of bound phenolics to the total phenolic content was significantly higher than that of free and esterified fractions. In wheat, phenolic compounds were concentrated mainly in the bran tissues. In the numerous in vitro antioxidant assays carried out, the bound phenolic fraction demonstrated a significantly higher antioxidant capacity than free and esterified phenolics. Thus, inclusion of bound phenolics in studies related to quantification and antioxidant activity evaluation of grains and cereals is essential.