Isosweetness concentrations of sucrose and high‐intensity sweeteners and antioxidant activity in white chocolate with functional properties

Healthier food products are an emerging trend in consumer demand. In this context, this study aimed at producing a prebiotic white chocolate with addition of an antioxidant source [goji berry (GB)] and replacement of sucrose by high‐intensity sweeteners (sucralose and rebaudioside A). The ideal sucrose level in white chocolate was determined as 40.46% (w/w). Different concentrations of dried GB (3%, 6% and 9%, w/w) in white chocolate did not affect consumers' preference. The isosweetness concentrations of the sweeteners were 0.05% for sucralose and from 0.10% to 0.16% (w/w) for rebaudioside A in prebiotic white chocolates. However, among the prebiotic chocolates containing GB, sucralose was the best sucrose substitute. The prebiotic white chocolates with GB showed antioxidant activity up to three times higher than the samples without the dried fruit, determined by ferric reducing antioxidant power and oxygen radical absorbance capacity methods. GB contributed to enhancing the nutritional value of white chocolate.     

Chemical,antioxidant and sensory properties of tomato‐watermelon‐pineapple blends,and changes in their total antioxidant capacity during storage

A conductometric analysis of the effect of condensate of peroxides generated during lipid oxidation in an accelerated stability test was adapted to test the hypothesis that total antioxidant capacity of tomato products would sometimes increase during processing and in storage. Tomato pulp blends made from a mixture of tomato (Lycopersicon esculentum var Roma VF), watermelon (Citrullus vulgaris var Babylack) and pineapple (Ananas comosus var Smooth cayennes) were analysed for basic quality profiles of dry matter, Brix, titratable acidity (TTA) and pH, total reducing sugars, Component antioxidants phytochemicals and total antioxidant capacity. The lowest sensory score (overall impression) of 4.80 ± 2.59 was recorded for tomato juice while, blend TWP 111p had highest score of 6.20 ± 1.99. There was significant difference (P < 0.05) in the basic quality profile of the pulp blends except for TTA values (0.37 ± 0.02 to 0.45 ± 0.05) and 2‐Furfurals (2.47 ± 0.03 to 2.71 ± 0.01). The fresh blend of 50% tomato, 25% watermelon and 25% pineapple had the highest total antioxidant capacity of 3.69 ± 0.52 mg 100 mL^?1 catechin equivalent. The total antioxidant capacity of the stored pulp increased from 2.95 ± 0.13 to 6.22 ± 0.32 mg 100 mL^?1 catechin equivalent in pasteurised TWP 211p blend by 60 days when stored at 40 °C. Total antioxidant status of tomato‐based fruit mix increased during the first 80 days.     

Effect of chlorophyll removal and particle size upon the nutritional and technological properties of powdered by‐products from artichoke (Cynara scolymus,L.) industrial canning

In this study, the effect of the particle‐size fractionation (Ø < 0.212 mm and 0.212 mm < Ø < 0.991 mm) and chlorophyll extraction on the nutritional and technological properties of the powdered artichoke ingredient was evaluated. The contents of minerals, protein, fat, carbohydrates and dietary fibre together with the content in bioactive compounds such as inulin and phenolics were determined. Other properties such as water‐ and oil‐holding capacities, water activity and antioxidant capacity were measured. The ingredient with chlorophyll and the lowest particle size presented the highest phenolic content and antioxidant capacity (8.4 mg of vitamin C equivalents per 100 g of dry matter) and water‐ and oil‐holding capacities. The removal of chlorophyll increased the oil‐holding capacity (from 59.7% to 94.6%), which was much higher than in the coarse ingredient (34%), but has a deleterious effect reducing the antioxidant capacity and the inulin content. The ingredients also showed high dietary fibre (22.5–33%), inulin (9–16%) and mineral (7.5–7.8%) contents. Although the ingredient with chlorophyll and smaller particle size had the higher antioxidant capacity, the removal of chlorophyll improved the technological properties to be used as food ingredient without affecting significantly to the nutritional value.     

Antioxidant Properties of Free,Soluble Ester and Insoluble‐Bound Phenolic Compounds in Different Barley Varieties and Corresponding Malts

Ten different barley cultivars and their corresponding malts were used to obtain different fractions. Phenolics extracted belonged to free, soluble esters and insoluble‐bound fractions. Total phenolic content (TPC) of the free fraction, as measured according to the Folin‐Ciocalteu method, ranged from 37.7 to 167.2 mg gallic acid equiv/kg of dried material (GAE/kg_dw) for barley and between 34.1 and 72.3 mg GAE/kg_dw for malt. The bound phenolic content ranged from 210.3 to 320.5 and between 81.1 and 234.9 mg GAE/kg_dw for barley and malt, respectively. The contribution of bound phenolics to the TPC was significantly higher than that of free and esterified fractions. Catechin and ferulic acid, quantified by high performance liquid chromatography with diode array detector (HPLC‐DAD), were the most abundant phenolics in the free and bound fractions, respectively. The p‐coumaric acid content was lower in hulless genotypes, as compared to hulled genotypes, showing that it is mainly concentrated in the hull. The antioxidant activities of the phenolic fractions were investigated using the radical scavenging assay (DPPH) and ferricyanide reducing power. The bound phenolics demonstrated a significantly higher antioxidant capacity compared to the free and esterified phenolics. During the malting process, a significant decrease of the bound phenolics was observed with a corresponding increase of the esterified fraction.     

Enzymatic and non‐enzymatic antioxidant systems of minimally processed cactus stems (Opuntia ficus‐indica Mill.) packaged under modified atmospheres

The aim of this work was to determine the enzymatic activities of catalase (CAT), superoxide dismutase (SOD) and ascorbate peroxidase (APX) together with the total phenolic and carotenoid contents and antioxidant capacity of two cultivars of cactus stems under modified atmosphere packaging containing a passive atmosphere, an active (with N₂) atmosphere and control (unsealed polyurethane trays) all stored at 4 ± 1 °C. Results indicated that Atlixco cultivar cactus stems had a shelf life that was twice as long (20 days) than that of Milpa Alta cultivar under N₂ MAP. The total enzyme activities of SOD, APX and CAT as well as the carotenoid content were higher in Atlixco than in Milpa Alta. The antioxidant enzymatic and non‐enzymatic systems as well as the antioxidant capacity and the phenolic content retention determined in Atlixco cactus stems under N₂ MAP appear to explain the longer postharvest life of this cultivar.     

Chemometric approach to the analysis of antioxidant properties and colour of typical Italian monofloral honeys

The antioxidant and colour properties of nine types of monofloral Italian honeys were analysed and correlated with multivariate analysis to find relationships able to characterise the honey floral source. Total phenolic content (TPC) and antioxidant activity of the honey samples increase in the order Citrus ≈ Black Locust < Sunflower ≈ Eucalyptus ≈ Coriander < Fir Honeydew ≈ Chestnut < Honeydew ≈ Strawberry Tree and mainly correlate with colour. A linear discriminant analysis was carried out to choose spectrophotometric λ able to characterise the colour of the different types of honey. Elaboration of data with cluster and principal component analyses enables differentiation among the floral source of some honey samples, namely Strawberry Tree, Honeydew, Citrus, Black Locust, Chestnut and Fir Honeydew.     

A comparison study between antioxidant and mutagenic properties of cysteine glucose-derived Maillard reaction products and neoformed products from heated cysteine and hydroxymethylfurfural

It was previously reported that Maillard reaction products (MRP) obtained from glucose with cysteine (1 M/0.25 M) mixtures and compounds generated during the mixing of heated cysteine with HMF solutions (Mix) were prone to inactivate various vegetal polyphenoloxidases (PPO). In this study, antioxidant properties of these model systems were compared using in vitro assays (AAPH°, DPPH° and TMM tests). Results showed that antioxidant activity observed in MRP and the Mix could be attributed to the sulfhydryl group of cysteine. The Mix behaved like a non-competitive inhibitor towards eggplant PPO (K_i = 0.7 μM). A highly active fraction, devoid of thiol compound and HMF, was obtained after fractionation of the Mix by SPE. The Mix was as efficient as metabisulfite in preventing enzymatic browning of apple puree (CIE-La^∗b^∗). MRP, the Mix and HMF could not be considered as mutagenic in the Salmonella microsome assay using Salmonella typhimurium TA98 and 102 strains.     

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.     

Cultivar choice provides options for local production of organic and conventionally produced tomatoes with higher quality and antioxidant content

BACKGROUND: Tomatoes (Solanum lycopersicum L.) are widely consumed and well known for their health benefits, many of which have been associated with the high levels of antioxidants present in tomatoes. With a growing interest in local and organic foods, it would be helpful to determine whether farmers could naturally improve the quality and antioxidant content of tomatoes for sale in local markets. This study evaluated antioxidant properties, quality attributes, and yield for 10 tomato cultivars grown for 2 years using certified organic and conventional practices. RESULTS: Cultivar and year effects impacted (P < 0.05) all tests conducted, while growing method influenced (P < 0.05) yield, soluble solids content, ascorbic acid, and antioxidant radical scavenging capacity. Even when accounting for year‐to‐year variability, cultivars in the highest groups had 1.35‐ to 1.67‐fold higher antioxidant levels than cultivars in the lowest groups. ‘New Girl’, ‘Jet Star’, ‘Fantastic’, and ‘First Lady’ were always in the highest groups, while ‘Roma’ and ‘Early Girl’ consistently had the lowest antioxidant content. CONCLUSION: Compared to production practices and environmental effects of years that are generally beyond the control of small‐scale producers, choice of cultivar provides the simplest and most effective means of increasing antioxidant properties. Knowledge of tomato cultivars with naturally higher antioxidant levels could assist smaller‐scale producers to grow fruit that may provide a competitive advantage and the opportunity to capitalize on the increasing popularity of locally grown, high‐quality fresh produce. Copyright © 2010 Society of Chemical Industry     

Phenylalanine ammonia lyase (PAL) enzyme activity and antioxidant properties of some cyanobacteria isolates

In the present study, six cyanobacteria isolates were evaluated for the PAL enzyme activity, and their methanol extracts were assessed for the total phenolic amount and other antioxidant parameters. Synechocystis sp. BASO444 and Synechocystis sp. BASO673 isolates with high levels of total phenols (66.0 ± 1.2 μg/mg, 78.1 ± 1.8 μg/mg, respectively) also showed high levels of PAL activities (20.5 ± 3.1 U/mg protein, 17.2 ± 2.3 U/mg protein, respectively) and strong antioxidant activities. To understand the effect of l-phenylalanine (l-phe) on the PAL activity, total phenolic amount, and phenolic constituents, isolates were evaluated with 100 mg/l l-phe. While PAL activities exhibited no significant change with l-phe addition, total phenolic amount of the isolates significantly increased. HPLC analysis revealed gallic acid, trans-cinnamic acid, p-coumaric acid, and ferulic acid as the main compounds. Results suggested that the two isolate mights be an important source for the l-phe inducible phenolic compounds.     

Physicochemical properties,antioxidant activity and inhibition of α‐glucosidase of a novel fermented pepper (Capsiccum annuum L.) leaves‐based vinegar

The aim of this study was to utilise by‐product pepper leaves for vinegar production due to its nutritional value. Changes in physicochemical and functional properties in four main process from raw material (leaves) to lactic acid (juice), alcohol (wine) and acetic acid (vinegar) fermentations were evaluated and compared. Their nutritional compositions were significantly different and particularly the wine and vinegar had higher total phenol content and their expanded diversity than the juice and then leaves (P < 0.05). Difference in values for phenolic compound was highly correlated with their α‐glucosidase inhibitory (AGI) and antioxidant capacities in DPPH and superoxide radical scavenging and reducing power assays (r = 0.919–0.981); vinegar ≥ wine > juice > leaves. Especially, AGI activity was greatly enhanced depending on fermentation steps beyond expectation. Thus, these data confirm that pepper leaves is a good functional source and the vinegar fermentation improved the functionality in stages.     

Flavour components and antioxidant properties of several cultivated mushrooms

Three mushrooms, Clitocybe maxima, Pleurotus ferulae and Pleurotus ostreatus grey strain were used to study their flavour components and antioxidant properties. The volatile flavour components found comprised of six eight-membered carbon compounds and two aromatic compounds. The content total of soluble sugars and polyols was 125–270 mg/g. The content of monosodium glutamate-like components was 1.76–8.89 mg/g. The contents of flavour 5′-nucleotides ranged from 1.89 to 7.59 mg/g. Based on the results obtained, three mushrooms possessed highly intense umami taste. Ethanolic extracts were more effective in the inhibition of conjugated diene and scavenging ability on 1,1-diphenyl-2-picrylhydrazyl radicals, whereas hot water extracts were more effective in the scavenging ability of hydroxyl radicals. EC₅₀ values were less than 14 and 30 mg/ml for ethanolic and hot water extracts, respectively, indicating that the three mushrooms were relatively effective as they exhibited antioxidant properties, despite having scavenging abilities for hydroxyl radicals. Phenols were the major antioxidant components and the total contents were 5.10–11.1 mg gallic acid equivalents/g.     

Comparing profiles and antioxidant properties of soluble and insoluble phenolics in Perilla frutescens seed flour extracts obtained by different extraction/hydrolysis methods

Cold‐pressed Perilla frutescens seed flour (CP‐PFSF) is a potential source of natural antioxidants. In this study, different methods were used to extract both soluble and insoluble phenolics from CP‐PFSF. Also, the phenolic profiles and antioxidant properties were compared. Results showed that soluble phenolics could be extracted using aqueous‐organic solvents, where 80% acetone resulted in the highest extraction yield and antioxidant activities. Insoluble phenolics remaining in residues could be released by acid or alkaline hydrolysis, where acid hydrolysis provided higher yield and antioxidant activities than alkaline. Soluble and insoluble phenolics could be extracted simultaneously through acid/alkaline hydrolysis, resulting in nearly the same yields for total phenolics. However, the phenolic components and antioxidant activities of extracts varied significantly, depending on the methods. Principal component analysis and correlation analysis revealed that a strategy of 80% acetone with successive acid hydrolysis steps released more rosmarinic acid, which have high antioxidant activities.