Effect of huitlacoche (Ustilago maydis DC Corda) paste addition on functional, chemical and textural properties of tortilla chips

AbstractThis study analyzed the addition of huitlacoche paste (HP) in baked tortilla chips (TC), evaluating its effects on functional, physicochemical and structural changes during processing. Two blue corn grains were nixtamalized, stone milled, air dried and milled to obtain flour; commercial blue corn flour (TM1) and commercial TC (TM2) were used as controls. Additions of 0, 3, 6 and 9% of HP were formulated; masas were prepared at 55% moisture content (MC), precooked and baked in an industrial machine. TC crispiness was influenced by grain characteristics and percentage of HP. Huitlacoche paste addition caused an increase in total dietary fiber (from 5.27 to 14.54%), total soluble phenolics content (from 17.52 to 37.60 mg GAE/100 g) and antioxidant capacity (from 6.74 to 7.98 μmol TE/g) in TC. Results suggest that tortilla chips added with huitlacoche can be an alternative to prepare this traditional edible fungus and produce healthier snacks, not fried and enriched with bioactive compounds.

Chemical quality parameters and bioactive compound content of brazilian berries

There is a growing consumer demand for higher healthy foods such as berries which are a rich source of phenolic compounds. The current work evaluated blackberry cultivars: Cherokee, Tupy and Xavante; raspberry cultivars: Heritage, Fallgold and Black; and the hybrid Boysenberry. All berries were grown under homogenous subtropical conditions in Brazil. Black raspberry, Cherokee and Tupy blackberry cultivars showed the highest ratio between soluble solid contents and titratable acidity, and Fallgold and Heritage raspberry showed the highest titratable acidity. Total phenolic content ranged from 2.03 to 5.33 g kg–1 fresh weight and total anthocyanin content registered values from 0.41 to 1.81 g kg–1 fresh weight. The most common phenolic acids were gallic, p-coumaric and ellagic, and for anthocyanins: cyanidin-3-glucoside and malvinidin-3-glucoside. Antioxidant capacity ranged from 14.13 to 21.51 mol equivalent trolox kg–1 fresh weight. Black raspberry, all blackberry cultivars and the Boysenberry hybrid are appropriate to be consumed fresh, while Fallgold and Heritage raspberries are recommended to the food industry. Due to their phenolic richness and antioxidant properties, these fruits are of great interest to the fresh fruit market and to pharmaceutical industries. These results could help breeders and growers when planning the cultivar selection according to their foreseeable destination.

Genetic variability for synthesis of bioactive compounds in peppers (Capsicum annuum) from Brazil

AbstractThe objective of this study was to evaluate the genetic variability for synthesis of bioactive compounds in pepper (Capsicum annuum, Solanaceae). Total phenolics, anthocyanins, carotenoids and antioxidant activity were evaluated in 14 accessions of Capsicum annuum from the Capsicum Genebank of Embrapa Temperate Agriculture (Pelotas – RS, Brazil). Thirty plants of each accession were cultivated in the field during spring and summer. The experimental design was a complete randomized block with 14 treatments (accessions) and three replications. The laboratory evaluations followed the same experimental design to field, but with two repetitions more. Seeds were discarded and opposite longitudinal portions of fruits were manually prepared for chemical analyzes. The data obtained showed high genetic variability for phenolics, anthocyanins, carotenoids and antioxidant activity. The P39, P77, P119, P143 and P302 accessions exhibited the highest levels of antioxidants, which are strongly indicated to be used in breeding programs of Capsicum peppers.

Anti-quorum sensing activity of phenolic extract from Eugenia brasiliensis (Brazilian cherry)

Abstract The aim of this study was to assess the anti-quorum sensing activity of phenolic extracts from grumixama (Eugenia brasiliensis), also known as Brazilian cherry, in concentrations that did not interfere with bacterial growth. The pulp phenolic compounds were extracted by using solid phage extraction in a mini-collumn C18 and quantified by spectrophotometry. The anti-quorum sensing activity was evaluated by testing the inhibition of violacein production in Chromobacterium violaceum and by evaluating the swarming motility in Aeromonas hydrophila and Serratia marcescens, both phenotypes regulated by quorum sensing. The phenolic extract strongly inhibited the production of violacein in C. violaceum, reducing its production in comparison with a control with no extract. No inhibition of growth was observed at the concentrations tested for quorum sensing inhibition. Confirming the quorum sensing inhibition phenotype, the extract was also able to inhibit swarming motility in S. marcescens and in A. hydrophila, although in the later the effect was marginal. Overall, these results indicate that phenolic extract from E. brasiliensis presents quorum sensing inhibitory activity most likely due to the presence of fruit phenolics which have been implicated as quorum sensing inhibitors in Gram negative bacteria.

Honey proteins and their interaction with polyphenols

This project aimed to determine the protein prof i les and concent rat ion in honeys, ef fect of storage condi t ions on the protein content and the interact ion between proteins and polyphenols. Thi r teen honeys f rom di f ferent botanical or igins were analyzed for thei r protein prof i les using SDS-PAGE, protein concent rat ion and phenol ic content , using the Pierce Protein Assay and Fol in-Ciocal teau methods, respectively. Protein-polyphenol interact ions were analyzed by a combinat ion of the ext ract ion of honeys wi th solvents of di f ferent polar i t ies fol lowed by LCjMS analysis of the obtained f ract ions. Results demonst rated a di f ferent protein content in the tested honeys, wi th buckwheat honey possessing the highest protein concent rat ion. We have shown that the reduct ion of proteins dur ing honey storage was caused, partially, by the protein complexat ion wi th phenolics. The LCjMS analysis of the peak elut ing at retent ion t ime of 10 to 14 min demonst rated that these phenolics included f lavonoids such as Pinobanksin, Pinobanksin acetate, Apigenin, Kaemferol and Myricetin and also cinnamic acid.

Elucidation of the components involved in the antioxidant activity of honey

Canadian honeys were analyzed for sugar concentration, honey colour, total phenolic content, the level of brown pigments, and antioxidant activity in order to elucidate the main components involved in the antioxidant activity of honey. By employing size-exclusion chromatography in combination with activity-guided fractionation, it was demonstrated that the antioxidant components are of high molecular weight (HMW), brown in colour and absorb at both 280nm and 450nm. The presence of brown HMW antioxidant components prompted an investigation on the influence of heattreatment on the Maillard reaction and the formation of melanoid ins. Heat-treatment of honey resulted in an increase in the level of phenolics in the melanoidin fractions which correlated with an increase in antioxidant activity. The preliminary results of this study suggest for the first time that honey melanoidins underlie the antioxidant activity of unheated and heat-treated honey, and that phenolic constituents are involved in the melanoidin structure and are likely incorporated by covalent or non-covalent interaction.

Activités antidiabétiques et neuroprotectrices du jus de bleuet biostransformé

Le bleuet démontre un potentiel thérapeutique dans le traitement du cancer et des maladies cardiovasculaires et neurodégénératives. Ces effets bénéfiques sont attribuables aux composés phénoliques abondants dans le bleuet, tels que les anthocyanines et les flavonoïdes. La biotransformation du jus de bleuet avec les bactéries Serratia vaccinii augmente sa teneur en composés phénoliques et son activité anti-oxydante, et modifie ses activités physiologiques. L’objectif de la présente étude est d’évaluer l’activité neuroprotectrice et le potentiel antidiabétique du jus de bleuet biostranformé (BJ). Le BJ est étudié dans différents tests dont : 1) La protection des neurones (N2a) contre le stress oxydatif (SO) induit par le peroxyde d’hydrogène; 2) La stimulation de la prise de glucose par les cellules musculaires (C2C12) et adipeuses (3T3-L1); 3) L’activité anti-hyperglycémique chez les souris obèses diabétiques KKAy. En effet, tandis que le jus de bleuet normal n’a aucun effet, le BJ augmente l’activité des enzymes anti-oxydantes, comme la catalase et la SOD (Superoxide Dimutase) et protège les neurones contre les changements de la signalisation des MAPKs et contre la toxicité induite par le peroxyde d’hydrogène. Le BJ augmente aussi la prise de glucose de 48% dans les cellules C2C12 et de 142% dans les cellules 3T3-L1. Cette augmentation n’est pas expliquée par une augmentation du calcium cytosolique mais plutôt par une stimulation de la phosphorylation de l’AMPK. De plus, le BJ inhibe l’adipogenèse chez les 3T3-L1. Le BJ diminue également l’hyperglycémie chez les souris obèses diabétiques KKAy et protège les jeunes souris pré-diabétiques contre le développement de l’obésité et du diabète. L’activité anti-hyperglycémique du BJ pourrait impliquer les adipokines puisque le BJ augmente le niveau d’adiponectine chez les souris diabétiques. Le BJ représente ainsi une approche prometteuse pour le traitement du diabète et les maladies neurodégénératives et une source de nouveaux agents thérapeutiques contre ces maladies.

Inter and intra-specific differences in medicinal plant use for the treatment of type II diabetes symptoms by the Cree Elders of Eeyou Istchee (QC)

Au Canada, nous remarquons une prédominance du diabète de type 2 au sein des communautés autochtones. Une approche ethnobotanique est utilisée en collaboration avec la Nation Crie de Eeyou Istchee afin de déterminer quels traitements à base de plantes peuvent être utilisés pour contrer les différentes conditions qui, collectivement, forment le diabète. Les pharmacopées de deux communautés cries, soit celles de Waskaganish et de Nemaska, ont été établies puis comparées à celles de étudiées antérieurement : communautés Whapmagoostui et Mistissini. Malgré les différences géographiques de ces groupes, leurs utilisations sont majoritairement semblables, avec pour seule exception le contraste entre les communautés de Nemaska et de Whapmagoostui. De plus, nous avons complété l’évaluation du taux cytoprotecteur des aiguilles, de l’écorce et des cônes de l’épinette noire (Picea mariana). Les extraits provenant de tous les organes des plantes démontrent une protection qui dépend de la concentration. La réponse spécifique d’organes peut varier selon l’habitat; ainsi, les plantes poussant dans les tourbières ou dans les forêts, sur le littoral ou à des terres l’intérieur démontrent des différences quant à leur efficacité. Bref, l’écorce démontre une relation dose-effet plus forte dans la forêt littorale, tandis que les aiguilles n’indiquent pas de changements significatifs selon leur environnement de croissance. La bioactivité observée démontre une corrélation avec le contenu phénolique et non avec l’activité de l’agent antioxydant. Ces résultats contribuent à péciser les activités antidiabétiques des plantes de la forêt boréale canadienne, telles qu’identifiées au niveau cellulaire par les guérisseurs Cries.

Studies on the Toughening of Epoxy Resins

This thesis aims to develop new toughened systems for epoxy resin via physical and chemical modifications. Initially the synthesis of DGEBA was carried out and the properties compared with that of the commercial sample. Subsequently the modifier resins to be employed were synthesized. The synthesized resin were characterized by spectroscopic method (FTIR and H NMR), epoxide equivalent and gel permeation chromatography. Chemical modification involves the incorporation of thermoset resins such a phenolics, epoxy novolacs, cardanol epoxides and unsaturated polyester into the epoxy resin by reactive belnding. The mechanical and thermal properties of the blends were studied. In the physical modification route, elastomers, maleated elastomers and functional elastomers were dispersed as micro-sized rubber phase into the continuous epoxy phase by a solution blending technique as against the conventional mechanical blending technique. The effect of matrix toughening on the properties of glass reinforced composites and the effect of fillers on the properties of commercial epoxy resin were also investigated. The blends were characterized by thermo gravimetric analysis, differential scanning calorimetry, dynamic mechanical analysis, scanning electron microscopy and mechanical property measurements. Among the thermoset blends, substantial toughening was observed in the case of epoxy phenolic novolacs especially epoxy para cresol novolac (ECN). In the case of elastomer blending , the toughest blends were obtained in the case of maleic anhydride grafted NBR. Among functional elastomers the best results were obtained with CTBN. Studies on filled and glass reinforced composites employing modified epoxy as matrix revealed an overall improvement in mechanical properties

Modification of Natural Rubber using Thermoset Resins

This thesis presents the findings of a study on incorporating vanous thermoset resins into natural rubber for property improvement. Natural rubber is an important elastomer with the unique attribute of being a renewable agricultural product. The study was undertaken to investigate the extent to which the drawbacks of natural rubber, especially its poor thermal and oil resistance propel1ies could be nullified by blending with common thermoset resins. A thorough and comparative understanding of the perfonnance of different resins from this viewpoint will be beneficial for both natural IUbber processors and consumers. In this study the thennoset resins used were epoxy resin, phenolics, epoxidised phenolics and unsaturated polyester resin.The resins were incorporated into NR during compounding and their effects on the properties of NR were studied after vulcanization. Properties were studied for both gum and filled N R compounds. The important properties studied are cure characteristics, mechanical properties, ageing propel1ies, thermal propel1ies, crosslink density and extractability. Characterization studies were also conducted using FTIR, TGA and DSC.Improvement in mechanical properties was noticed in many cases. The results show that most resins lead to a reduction in the cure time of NR. The perfonnance of epoxy resin is most noticeable in this respect. Mechanical properties of the modified IUbber show maximum improvement in the case of epoxidised novolacs. Most resins are seen to improve the thermal and oil resistance propel1ies of NR. Epoxy novolacs show maximum effect in this respect also. However the presence of tillers is found to moderate the positive effects of the thermoset resins considerably.

Modification of Phenol Formaldehyde Resin for Improved Mechanical Properties

Phenolic resins suffer from the presence of microvoids on curing. This often leads to less than satisfactory properties in the cured resin. This disadvantage has limited the use of phenolic resins to some extent. This study is an attempt to improve the mechanical properties of the phenolic resol resins by chemical modification aimed at reducing the microvoid population. With this end in view various themoset resins synthesised under predetennined conditions have been employed for modifying phenolic resols. Such resins include unsaturated polyester, epoxy and epoxy novolac prepolymers. The results establish the effectiveness of these resins for improving the mechanical properties of phenolics. Experimental and analytical techniques used include FTIR, DMA, TGA, SEM and mechanical property evaluation. While most of the modifier resins employed give positive results the effect of adding UP is found to be surprising as well as impressive.

Biodegradation of phenolic compounds in different ecosystems in Cochin

The purpose of this study is to determine the ability of specifically adapted bacteria to degrade phenol and to quantify the rate of biodegradation at. Different concentrations by mixed as well as individual isolates. Regular quantitative analysis of phenolics and aerobic phenololytic heterotrophs from five different ecosystems were done during 1990-1991, and the ability of microorganisms isolated from those areas, to utilize phenol, o-cresol and orcinol was also studied. In addition, data on environmental parameters like temperature, dissolved oxygen, salinity, pH, organic carbon and nutrients were also collected during the period of study The present study is one of its first kind in natural aquatic environment and has aimed to bring out some idea about the potential phenol biodegrades in such environments where the phenol concentration is beyond permitted level.

Phenolic contents of lettuce, strawberry, raspberry, and blueberry crops cultivated under plastic films varying in ultraviolet transparency

The levels of health-related phytochemicals were determined in lettuce leaf and in strawberry, raspberry and blueberry fruits grown in near-commercial conditions under plastic films of three different UV transparencies. In the red lettuce Lollo Rosso, total phenolics, anthocyanin, luteolin and quercetin levels were all raised by changing from a UV blocking film to a film of low UV transparency, and to a film of high UV transparency. The related green lettuce, Lollo Biondo, cultivated under the same conditions, showed virtually no phytochemical responses to the same variation in UV levels. Overall, the phenolic levels of strawberries, raspberries, and blueberries were unresponsive to the UV transparency of the plastic film under which the crops were grown. The significance of these findings is discussed in relation to the nutritional quality of soft fruit and salad crops which are increasingly being grown commercially under plastic tunnels.

Chemical composition and in vitro fermentation of tannin-rich tree fruits

Dry and mature tree fruits are a potential source of protein for goats in the semi-arid areas of southern Africa, but their chemical composition and feeding value is largely unknown. This study presents the chemical composition and in vitro fermentation of indehiscent whole fruits and separated seed and hull fractions from Acacia nilotica, Acacia erubescens, Acacia sieberiana, Acacia erioloba, Piliostigma thonningii and Dichrostachys cinerea trees. Results indicate that the N contents of whole fruits ranged between 13.5 g/kg DM (A. nilotica) and 27.1 g/kg DM (A. erubescens). Seeds had a higher N content than hulls for all tree species. A. nilotica, D. cinerea and P thonningii fruits had high levels of extractable phenolics (758, 458 and 299 g/kg DM, respectively). Soluble phenolics (SPh) and ytterbium precipitable phenolics (YbPh) levels were negatively correlated to in vitro gas production but positively correlated to in vitro organic matter degradability (iOMD). Partition factors for whole fruits at 48 h ranged between 3.6 mg/ml for A. erioloba and 7.8 mg/ml for A. nilotica. Seeds of A. erioloba, A. erubescens and P thonningii were consistently fermented more efficiently throughout the incubation period compared to their whole fruits or hulls. Estimating in vitro degradability of phenolic-rich substrates through filtration procedures can give erroneous results due to the loss of soluble phenolics, which are not necessarily degradable. The feeding value of fruits from D. cinerea and A. nilotica tree species may be reduced due to the presence of high levels of phenolics. (C) 2007 Elsevier B.V. All rights reserved.

In vitro biological activity of tannins from Acacia and other tree fruits: Correlations with colorimetric and gravimetric phenolic assays

This Study was designed to investigate impact of tannins on in vitro ruminal fermentation parameters as well as relationships between concentration and in vitro biological activity of tannins present in tree fruits. Dry and mature fruits of known phenolic content harvested from Acacia nilotica, A. erubescens, A. erioloba, A. sieberiana, Piliostigima thonningii and Dichrostachys cinerea tree species were fermented with rumen fluid in vitro with or without polyethylene glycol (PEG). Correlation between in vitro biological activity and phenolic concentration was determined. Polyethylene glycol inclusion increased Cumulative gas production from all fruit substrates. The largest Increase (225%) after 48 h incubation was observed in D. cinerea fruits while the least (12.7%) increase was observed in A. erubescens fruits. Organic matter degradability (48 h) was increased by PEG inclusion for all tree species except A. erubescens and P. thonningii. For D. cinerea fruits, colorimetric assays were poorly correlated to Increases In gas production due to PEG treatment. Ytterbium precipitable phenolics (YbPh) were also poorly correlated with response to PEG for A. erioloba and P. thonningii fruits. However, YbPh were strongly and positively correlated to the increase In Cumulative gas production due to PEG for A. erubescens and A. nilotica. Folin-Ciocalteau assayed phenolics (SPh) were not correlated to response to PEG in P. thonningii and A. sieberiana. It was Concluded that the PEG effect oil in vitro fermentation was closely related to some measures of phenolic concentration but the relationships varied with tree species.