Colour is one of the main sensory characteristics of berry juice and fruit products and this parameter also powerfully impacts on consumer behaviour. However, the colour of berry juices is unstable and degradation occurs during storage. The main objectives of the project were: to determine the mechanism by which boysenberry juice enhances the colour of other berry juices and to determine if its addition to berry juices will also stabilise the anthocyanin pigments and enhance copigmentation. In this study, total anthocyanin, total phenolic acids, hyperchromic and bathochromic shift and the rate of colour degradation was measured by spectrophotometric techniques. Individual anthocyanin and phenolic acid content were measured in each juice by high performance liquid chromatography (HPLC) were evaluated during storage at 5, 20 and 35?C. Boysenberry juice improved the colour of blackcurrant, cranberry and pomegranate juices immediately after addition; however, only blackcurrant juice colour was stable during storage at 5?C. There was no influence on the stability of total anthocyanins in pomegranate or cranberry juices when boysenberry juice was added. Of the three juices, pomegranate had the highest rate of degradation. The total anthocyanin of blackcurrant enhanced with boysenberry juice was more stable than for cranberry and pomegranate juices. The impact of phenolic acids found in boysenberry juice (kaemferol, quercetin and ellagic acid) on blackcurrant juice colour stability was also investigated. The colour stability of blackcurrant juice was improved by the addition of ellagic acid at 5?C; however, the colour intensity of blackcurrant enhanced with kaemferol and quercetin decreased with storage. The copigmentations between anthocyanins themselves were not found to be a significant effect on colour stability of blackcurrant juice. Ellagic acid had the strongest colour improvement in blackcurrant juice compared to boysenberry juice. In conclusion, ellagic acid as found in boysenberry juice formed intermolecular copigmentation with blackcurrant juice anthocyanins, so this resulted in stabilised juice colour during storage; however, the effect was found when the juice was stored at 5?C only.

In den letzten Jahren gerieten phenolische Substanzen, wie z.B. Chlor-, Nitrophenol oder Alkylphenolethoxylate aufgrund ihrer Toxizität sowie ihres kanzerogenen und endokrinen Potentials in das Interesse der Öffentlichkeit. Diese Substanzen gelangen in großen Mengen, z.B. aus industriellen Prozessen (Papier-, Kunststoff-, oder Lederindustrie) oder als Abbauprodukte von Pflanzenschutzmitteln in die Umwelt.<br /> <br /> Ziel dieser Arbeit war es, einfache biochemische Bestimmungsmethoden für verschiedene phenolische Umweltschadstoffe auf Basis biochemischer Erkennungselemente zu entwickeln. Diese sollten als Screeningmethoden in der Vor-Ort-Analytik einsetzbar sein. Die Anwendung sollte kostengünstig und einfach durchzuführen sein, so dass die Messung kein hochwissenschaftliches Personal erfordert. Daher stand im Hintergrund der Arbeit die Integration der Analysenmethode in ein kompaktes Handgerät.<br /> <br /> Zu diesem Zweck wurde ein Biosensor entwickelt der zur direkten Messung und in Kombination mit einem Immunoassay einsetzbar ist:<br /> <br /> 1.) Elektrochemischer Biosensor<br /> Ein elektrochemischer Biosensor stellt die Verbindung zwischen einer Elektrode und der biologischen Komponente dar. Als Messprinzip wurde die Amperometrie gewählt. Hierbei wird die Präsenz des nachzuweisenden Stoffes durch die angelegte Spannung am Sensor visualisiert, da beim Vorhandensein ein Stromfluss gemessen wird.<br /> <br /> Um die Signalintensität zu erhöhen können Enzyme als Katalysatoren genutzt werden, die in der Lage sind die Rückreaktion der Elektrodenreaktion zu realisieren. In diesem Fall wurde Glucose-Dehydrogenase (GDH) verwendet, die oxidierte phenolische Verbindungen reduzieren kann. Zusammen mit der Oxidation an der Sensoroberfläche bildet sich ein Verstärkungszyklus aus, der das ursprüngliche Signal vielfach erhöht.<br /> <br /> Wir waren in der Lage, GDH durch Einbetten in ein Polymerennetzwerk auf der Oberfläche einer gedruckten Platin-Dickschicht-Elektrode zu immobilisieren. Als Resultat erhielten wir einen sehr empfindlichen und äußerst stabilen Biosensor. Seine schnelle Ansprechzeit ermöglicht den Einsatz in automatisierten Fließsystemen zur Messung großer Probenzahlen. Der Einsatz in einem manuell betriebenen Handgerät konnte ebenfalls realisiert werden und brachte nur geringe Beeinträchtigungen in bezug auf die Empfindlichkeit der Messung. Die erfolgreiche Implementierung des Biosensors in das Handgerät wurde in Rahmen eines internationalen Workshops in Barcelona, anhand der Überprüfung der Reinigungsleistung von Klärwerken, gezeigt.<br /> <br /> 2.) Kombination mit Immunoassays<br /> Der Einsatzbereich der GDH-Biosensoren lässt sich durch die Kombination mit anderen Techniken erweitern, wobei der Sensor zur Visualisierung der Nachweisreaktion dient. In diesem Fall kann der Sensor zur Bestimmung der Enzymaktivität von ß?Galactosidase (ßGal) verwendet werden. Der Nachweis geringster Enzymmengen wurde realisiert. Die ßGal wird zur Markierung eines Analytanalogen in Immunoassays verwendet, um die Bindung von Antikörper und Analytmolekül sichtbar zu machen. Im Immunoassay bildet sich ein Gleichgewicht zwischen Antikörper, unmarkiertem Analyt und markiertem Analytanalog (Tracer) aus. Über die Bestimmung der Enzymaktivität kann man die Analytkonzentration in der Probe errechnen.<br /> <br /> Wir haben unseren GDH-Biosensor erfolgreich mit zwei Techniken kombiniert. Zum Einen mit einem Assay zur Bestimmung von Nitrophenol, der in einem automatisiertem Fließsystem realisiert wurde. Hier wird die Mischung aus Antikörpern, Analyt und Tracer über eine Säule gegeben und gespült. Die gebundenen Bestandteile werden durch den GDH-Biosensor quantifiziert.<br /> <br /> Zum Anderen wurde ein Kapillarimmunoassay entwickelt, der in das Handgerät integriert werden kann. Dabei wird der Antikörper direkt an der Kapillare fixiert. Die Probe wird mit Tracer vermischt und in die Kapillare gegeben. Dort bildet sich das Gleichgewicht aus und weitere Probenbestandteile werden im Spülschritt eliminiert. Die Analytkonzentration wird durch die Bestimmung des gebunden Tracers (Aktivität der ßGal) mit Hilfe des GDH-Biosensors realisiert. / The development of fast and reliable biochemical tools for on-site screening in environmental analysis was the main target of the present work. Due to various hazardous effects such as endocrine disruption and toxicity phenolic compounds are key analytes in environmental analysis and thus were chosen as model analytes.<br /> <br /> Three different methods were developed:<br /> <br /> For the enzymatic detection of phenols in environmental samples an enzyme-based biosensor was developed. In contrast to reported work using tyrosinase or peroxidases, we developed a biosensor based on glucose dehydrogenase as biorecognition element. This biosensor was devoted for an application in a laboratory flow system as well as in a portable device for on-site measurements.<br /> <br /> This enzymatic detection is applicable only for a limited number of phenols due to substrate specificity of the enzyme. For other relevant compounds based on a phenolic structure (i.e. nitrophenol, alkylphenols and alkylphenol ethoxylates) immunological methods had to be developed. The electrochemical GDH-biosensor was used as the label detector in these immunoassays.<br /> <br /> Two heterogeneous immunoassays were developed where ßGal was used as the label. An electrochemical method for the determination of the marker enzyme activity was processed. The separation step was realized with protein A/G columns (laboratory flow system) or by direct immobilization of the antibodies in small disposable capillaries (on-site analysis). <br /> <br /> All methods were targeted on the contemporary analysis of small numbers of samples.

The long-term performance of stabilized polyolefins in different environments was studied with focus on antioxidant consumption and migration. Plaques of linear polyethylene (LPE) and branched polyethylene (BPE) were stabilized with Santonox® R (4,4'-Thiobis(6-tert-butyl-3-methylphenol)), Irganox® 1081 (2,2’-Thiobis(4-methyl-6-tertbutylphenol)), or Lowinox® 22M46 (2,2’-Methylenebis(6-tert-butyl-4-methylphenol)). The samples were aged in water and nitrogen at 75, 90 and 95°C. Antioxidant concentration profiles were obtained by oxidation induction time (OIT) measurements using differential scanning calorimetry (DSC). The very flat antioxidant concentration profiles of the plaques exposed to non-aqueous media indicated that the migration of antioxidant to the surrounding medium was controlled by the low evaporation rate at the sample boundary. The samples of BPE and Santonox R were also exposed to air and water saturated with air. The similarity of the antioxidant concentration profiles of Santonox R obtained after ageing in air and nitrogen suggested that the fraction of antioxidant oxidized is negligible in comparison with the loss of antioxidant by migration to the surrounding media. The loss of Santonox R in samples exposed to water saturated with air was faster than for the samples exposed to oxygen-free water. This was due to increased mass transport of the antioxidant from the polymer phase boundary to the water phase when oxygen was present. An unexpected higher migration rate from LPE than from BPE was proposed to be due to the low boundary loss rate in BPE, caused by the presence of a thin liquid-like (oligomeric) surface layer developed during ageing. A quantitative relationship was found between the boundary loss rate to water and the polarity of antioxidants. The antioxidant diffusivities were approximately equal in LPE and BPE, indicating that the constraining effect of the crystals on the non-crystalline fraction did not affect the antioxidant molecules. Results obtained by liquid chromatography of extracts confirmed that the gradual decrease in OIT with increasing ageing time was due to migration of antioxidant to the surrounding medium. Pipes of high-density polyethylene stabilized with hindered phenols and phosphites were exposed to chlorinated water at elevated temperatures. OIT showed that the stabilizing system was rapidly chemically consumed by the action of chlorinated water. Size exclusion chromatography and DSC showed extensive polymer degradation strictly confined to the immediate surface of the unprotected inner wall material and to the amorphous phase of the semicrystalline polymer. The rate of growth of the layer of highly degraded polymer was constant. Pipes of isotactic polybutene-1 were pressure-tested in chlorinated water at a controlled pH, and the lifetime was assessed as a function of temperature and chlorine content. The lifetime shortening in chlorinated water was significant even at relatively low chlorine contents, 0.5 ppm. A further increase of chlorine content led to only a moderate shortening of the lifetime. The temperature dependence of the lifetime data obeyed the Arrhenius law. The decrease of the antioxidant concentration was independent of the chlorine concentration in the range of 0.5-1.5 ppm. The time to reach depletion of the antioxidant system could be predicted by linear extrapolation. / QC 20101020

A la primera part d’aquesta tesi doctoral s’ha portat a terme l’anàlisi de composició bàsica de 16 productes flequers i de brioixeria tradicionals de la província de Lleida. Els resultats obtinguts indiquen que existeix una gran variabilitat a la composició nutricional dels productes estudiats, derivada de les matèries primeres utilitzades, de la seva formulació i dels processos d’elaboració. La segona part de la tesi s’ha centrat en la millora de les propietats tecnològiques i dels perfils nutricional i sensorial del pa a través de la incorporació d’oli d’oliva verge com a ingredient. Amb aquesta finalitat s’han estudiat els efectes de l’addició d’oli d’oliva a diferents nivells (0-75%) sobre les propietats fisicoquímiques i reològiques de la massa de pa y els efectes sobre el producte final en termes de volum específic, perfil sensorial i composició nutricional. Els pans elaborats amb 4%, 10% i 20% d’oli d’oliva verge han mostrat bones propietats reològiques; no obstant, únicament els dos primers han estat acceptats sensorialment. La tercera part de la tesi s’ha centrat en millorar el contingut fenòlic del pa elaborat amb un 10% d’oli d’oliva verge, per això ha estat necessari establir el procediment d’extracció i quantificació de compostos fenòlics d’una matriu de pa. A més s’ha estudiat la millor combinació temperatura-temps-format de cocció del producte per a minimitzar la pèrdua de compostos fenòlics i maximitzar la preservació del contingut fenòlic inicial. A partir de l’anàlisi sensorial i de la quantificació de fenols, el pa formulat amb oli d’oliva Arbequina enriquit en compostos fenòlics ha estat l’escollit com a producte finalista. / En la primera parte de esta tesis doctoral se ha llevado a cabo el análisis de composición básica de 16 productos de panadería y bollería tradicionales de la provincia de Lleida. Los resultados obtenidos indican que existe una gran variabilidad en la composición nutricional de los productos estudiados, derivada de las materias primas utilizadas, de su formulación y de los procesos de elaboración. La segunda parte de la tesis se ha centrado en la mejora de las propiedades tecnológicas y de los perfiles nutricional y sensorial del pan a través de la incorporación de aceite de oliva virgen como ingrediente. Con esta finalidad se han estudiado los efectos de la adición de aceite de oliva a distintos niveles (0-75%) sobre las propiedades físico-químicas y reológicas de la masa panaria, y sus efectos sobre el producto final en términos de volumen específico, perfil sensorial y composición nutricional. Los panes elaborados con 4%, 10% y 20% de aceite de oliva virgen han mostrado buenas propiedades reológicas; sin embargo únicamente los dos primeros han sido aceptados sensorialmente. La tercera parte de la tesis se ha centrado en mejorar el contenido fenólico del pan elaborado con un 10% de aceite de oliva virgen, para lo que se ha establecido el procedimiento de extracción y cuantificación de compuestos fenólicos de una matriz panaria. Además se ha estudiado la mejor combinación temperatura-tiempo-formato de cocción del producto para minimizar la pérdida de compuestos fenólicos y maximizar la preservación del contenido fenólico inicial. A partir del análisis sensorial y de la cuantificación de fenoles, el pan formulado con aceite de oliva Arbequina enriquecido en compuestos fenólicos ha sido escogido como el producto finalista. / In the first part of this doctoral thesis the basic composition analysis of 16 baked and pastry traditional products of Lleida province has been carried out. The obtained data indicates that there is a great variability in the nutritional composition of the studied products, which is derived of raw materials used, of their formulation and manufacturing processes. The second part of the thesis has been focused on the improvement of technological properties and of nutritional and sensorial profiles of bread through the addition of virgin olive oil as ingredient. For this purpose the effect of addition of different levels of virgin olive oil (0-75%) on physiochemical and rheological properties of bread dough, and its effects on final product in terms of specific volume, sensory profile and nutritional composition have been studied. Bread made with 4%, 10% and 20% of virgin olive oil showed good rheological properties, but only the first two were considered acceptable from sensory analyses. The third part of the thesis has been focused on improving the phenolic content of the bread made with 10% of virgin olive oil; to achieve it, establishing the phenolic compounds extraction and quantification procedure of a bread matrix has been necessary. Furthermore the best combination temperature-time-format of product baking to minimize the lost of phenolic compounds and maximize the preservation of initial phenolic content has been studied. From sensory analyses and phenolic quantification, the bread formulated with Arbequina olive oil enriched with phenolic compounds has been chosen as finalist product.

Målet med detta arbete är att undersöka smörjsystemet på två utsatta leder på en Boomer E2C. Förfrågan om examensarbetet kommer från Atlas Copco Rock Drills AB i Örebro som också tillverkar maskinen. Atlas Copco Rock Drills AB har idag ett fettsmörjningssystem som upprätthåller funktionerna på lederna. Uppgiften är att sammanfatta och utvärdera dagens system samt att finna nya lösningsförslag som skulle kunna ersätta eller delvis ersätta systemet. Information har hämtats från dokumentation, ritningar och samtal med konstruktörer på företaget. Efter att alla förutsättningarna för lederna specificerats så har lösningsförslag sökts. Genom att träffa lagerleverantörer och söka artiklar så har idéer formats. Brainstorming har använts för att kunna se nya lösningar. Undersökningen har visat att det finns problem med dagens lösning vad gäller slanghaverier och driftstopp i fält. Atlas Copco AB uttrycker även att kunskapen och dokumentationen angående systemet är otillräckligt. Efter artikelsökning så kan konstateras att forskningen och kunskapen på området med tungt belastade, oscillerande och fettsmörjda leder är liten. Dimensionering sker ofta med hjälp av erfarenhet och med tankesättet ”det har fungerat förut”. När lösningsförslagen har jämförts så har detta gjorts genom att använda metoden AHP (Analytic Hierachy Process). Med denna metod så jämför man kriterierna från kravspecifikationen med lösningsförslag så att man matematiskt kan räkna fram ett vinnande lösningsförslag. Resultatet visar att en smörjfri lösning skulle teoretiskt vara att föredra. Denna skulle tillverkas av en modern polymer och kompletteras med en inre tätning och ett yttre skydd. Atlas Copco rekommenderas att testa de olika förslagen för att komma fram till vilken som är bäst lämpad för applikationen. / The goal of this work is to investigate the lubrication system on two exposed joints on a Boomer E2C. The request for the thesis comes from Atlas Copco Rock Drills AB, Örebro, which also manufactures the machine. Today Atlas Copco Rock Drills AB has a grease lubrication system that secures the function of the joints. The task is to summarize and evaluate the current systems and to find new solutions that would be able to replace or partially replace the current system. Information was gathered from documents, construction drawings and conversations with engineers at the company. Solutions and ideas have been formed by meeting stock suppliers and searching for articles. Brainstorming has been used in order to find new solutions. The investigation has shown that there are problems with the current solution in terms of hose failures and downtime in the field. Atlas Copco AB also expresses that there is a lack of documentation and knowledge regarding the lubrication system. After the various article searches it became clear that research and knowledge in the area with heavy duty, oscillating and grease lubricated joints is insufficient. The design is often done with the help of experience and with the mindset "it has worked before." When the solutions and ideas have been compared, this has been done by using AHP (Analytic Hierarchy Process). This method compares the criteria that must be fulfilled by the solutions and then calculates the best one. The results show that a lubrication-free solution would theoretically be preferable. This would be produced by a modern polymer and supplemented with an inner seal and an outer protection. Atlas Copco is recommended to test the various proposals to be able to decide which the best solution for the application is.

In this study, extraction of phenolic compounds from sour cherry, peach and apple pomaces using high pressure extraction (HPE) and subcritical CO2 extraction (SCE) was investigated considering total phenolic content (TPC) and antiradical efficiency (AE). Different combinations of pressure (50, 125, 200 MPa), temperature (20, 40, 60&amp / #61616 / C), solid/solvent ratio (0.05, 0.15, 0.25 g/ml) and extraction time (10, 25, 40 min) were used for HPE according to the Box-Behnken experimental design. The variables used for SCE were pressure (20, 40, 60 MPa), temperature (40, 50, 60&amp / #61616 / C), ethanol concentration (14, 17, 20 wt%) and extraction time (10, 25, 40 min). For HPE, TPC and AE at the optimum conditions were 3.80 mg gae/g sample and 22 mg DPPH&amp / #729 / /g sample for sour cherry pomace, 0.93 mg gae/g sample and 6.40 mg DPPH&amp / #729 / /g sample for peach pomace and 2.08 mg gae/g sample and 10.80 mg DPPH&amp / #729 / /g sample for apple pomace, respectively. For SCE, TPC and AE at the optimum conditions were 0.60 mg gae/g sample and 2.30 mg DPPH&amp / #729 / /g sample for sour cherry pomace, 0.26 mg gae/g sample and 1.50 mg DPPH&amp / #729 / /g sample for peach pomace and 0.47 mg gae/g sample and 3.30 mg DPPH&amp / #729 / /g sample for apple pomace, respectively. Efficiency of HPE and SCE methods was compared with solvent extraction (SE). TPC and AE of the extracts obtained by HPE were close to those obtained by SE but the efficiency of SCE was low compared to HPE and SE. SCE was a better extraction method for apple and peach pomaces compared to sour cherry pomace.

Chiral Baeyer-Villiger (BV) oxidation of cyclic ketones allows rapid access to asymmetric lactones as valuable intermediates in organic chemistry and frequently encountered precursors in enantioselective synthesis. In the first part, BV oxidation of functionalized ketones, especially cyclic &amp / #61537 / -hydroxy and acetoxy ketones is described which could be a straightforward route to the &amp / #61537 / -hydroxy lactones and &amp / #61537 / -hydroxyalkanoic acid derivatives. The &amp / #61537 / -acetoxylation of indanone, tetralone and chromanone derivatives by using Mn(OAc)3 followed by the enzyme catalyzed kinetic resolution of acetoxy ketones gives both of the enantiomers of &amp / #61537 / -acetoxy ketones in good chemical and optical yields. The Bayer-Villiger oxidation of &amp / #61537 / -acetoxy ketones with m-CPBA, CF3SO3H, and CH2Cl2, at rt gives the corresponding lactones without racemization. The phenyl moiety migrates selectively in order to form lactones. The mild hydrolysis of lactones affords phenolic &amp / #61537 / -hydroxycarboxylic acid derivatives. Because of the high importance of pyrrole derivatives which exist in the structure of many natural products possessing biological activity beside their valuable feature of being versatile building blocks in organic synthesis and important starting materials for various synthetic transformations, a convenient method for the synthesis of 1,2,3,5-tetrasubstituted pyrrole derivatives starting from 1,3,-dicarbonyl compounds throuh acid catalyzed cyclization reaction is presented in the second part of the thesis. Alkylation of 1,3-dicarbonyl compound with propargyl bromide followed by one step cyclization with the introduction of primary amines in the presence of catalytic amount of trifluoroacetic acid (TFA) affords the corresponding pyrrole derivatives in high yields. The third part of the thesis describes the cyano-phosphorylation of various alkyl and aryl phosphonates in the presence of diethyl cyanophosphonate (DEPC) as the phosphorylating agent under the promotion of the KCN catalyst. Reaction of acyl phosphonates with DEPC forms the phosphonocyanohydrin-O-phosphates which are the important starting materials of quaternary &amp / #945 / -hydroxy carboxylic acid and phosphonate containing &amp / #946 / -aminoalcohol derivatives.

Fenolinės rūgštys ir fenilpropanoidai pasižymi reikšmingu biologiniu aktyvumu ir yra vaistinių žaliavų veiklieji komponentai. Įteisintų tyrimo metodikų vystymas šių junginių nustatymui (kokybiniam ir kiekybiniam žaliavų tyrimui) yra ypač svarbus augalinių vaistinių preparatų efektyvumo, saugumo ir kokybės kontrolei. Iš skirtingų Lietuvos regionų buvo surinkta 18 propolio pavyzdžių. Atlikto darbo tikslas - analitiniais metodais ištirti Lietuvoje surinktų propolio pavyzdžių cheminę sudėtį, bei kiekybiškai ir kokybiškai įvertinti šias fenolines rūgštis ir fenilpropanoidus: chlorogeno rūgštį, cinamono rūgštį, galo rūgštį, ferulo rūgštį, kavos rūgštį, kumaro rūgštį, protokatecho (3,4-dihidroksibenzoinę) rūgštį, rozmarino rūgštį, vaniliną ir vanilino rūgštį. Atlikti tyrimai paprastos ir greitos atvirkštinių fazių efektyviosios skysčių chromatografijos metodikos optimizavimui ir įtiesinimui. Sukurto crhromatografinio metodo judrioji skystoji fazė yra metanolis ir 0,5 procento acto rūgšties tirpalas vandenyje. Esant optimalioms atskyrimo sąlygoms (aprašytoms skyriuje „Tyrimo metodas“), analizė atliekama 27 min., sulaikymo laikas 4,04 min (galo rūgštis), 6,93 min (protokatecho rūgštis), 11,30 min (chlorogeno rūgštis), 12,26 min (vanilinė rūgštis), 12,93 min (kavos rūgštis), 13,80 min (vanilinas), 16,97 min (kumaro rūgštis), 17,95 min (ferulo rūgštis), 22,29 min (rozmarino rūgštis) ir 26,30 min (cinamono rūgštis). Aptikimo riba ir nustatymo riba buvo atitinkamai tarp 0,004–0,021 ir 0,0... [toliau žr. visą tekstą] / The phenolic acids and phenylpropanoids have an important biological activity and are therapeutic agents of crude drugs. Development of validated analysis techniques of these phytotherapeutic agents (fingerprinting and assay procedures) is an important practice for efficacy, safety and quality control of herbal drug preparations. 18 samples of propolis were collected from different districts of Lithuania. The aim of the present work was to study chemical composition of collected samples and estimate analytical capabilities of the evaluation of selected phenolic acids and phenylpropanoids: caffeic acid, chlorogenic acid, cinnamic acid, coumaric acid, ferulic acid, gallic acid, protocatechuic (3,4-dihydroxybenzoic) acid, rosmarinic acid, vanillic acid and vanillin. Optimization and validation procedures of rapid and simple method of reversed phase high performance liquid chromatography were carried out. The mobile phase of the optimized chromatographic method consisted of methanol and 0.5 per cent acetic acid solvent in water. Under the optimal separation conditions (described in Methods), analysis was done in 27 min, with the retention times 4.04 min (gallic acid), 6.93 min (protocatechuic acid), 11.30 min (chlorogenic acid), 12.26 min (vanillic acid), 12.93 min (caffeic acid), 13.80 min (vanillin), 16.97 min (coumaric acid), 17.95 min (ferulic acid), 22.29 min (rosmarinic acid) and 26.30 min (cinnamic acid). The limits of detection and the limits of quantitation were between... [to full text]

Berry ripening in lowbush blueberry (Vaccinium angustifolium Ait.) is influenced by developmental, physiological and climatic factors resulting in a heterogenous mix of maturities at harvest. This study characterizes the physico-chemical changes which occur during fruit ontogeny and links ripening patterns to micoclimate. Individual clones in five commercial fiels were followed in the 2006 and 2007 growing seasons. Phenolic acids, flavonols, and flavan-3-ols decreased and anthocyanins increased with maturity. Peak maturity consistently occurred at 1200 accumulated growing degree days (GDD). There was a sharp decline in fruit retention at the end of the growing season suggesting a date after which harvested yield declines but no consistent pattern was detected between years or fields.The consistency of GDD accumulation in relation to ripening pattern suggests GDDs can be used as a predictive ripening index. The physico-chemical nature of ripe berries indicates ripe berries could be harvested earlier than is currently the practice.

Phenolic compounds have attracted much attention due to numerous health benefits, including high antioxidant properties, reduced risk of cancer, and inhibition of digestive enzymes. Recent research has suggested that different phenolic compounds may interact with starch. The first objective was to investigate the effect of green or black tea extracts on hydrolysis of wheat, rice, corn, and potato starches. Cooking starches in the presence of either tea reduced their hydrolysis. Potato starch cooked with black tea was the most effective treatment. Observations suggested that hydrolysis may be affected by interactions and by impact on specific enzymes based on starch structure. The second objective was to determine if similar effect could be observed in product system. Addition of green tea extract to sponge cake significantly reduced in vitro starch digestibility, thus could reduce the expected glycemic index. In addition, significant increases in dietary fibre, resistant starch, and antioxidant properties were observed.