Investigations were carried out to isolate, identify, and to characterize, major volatile components of tomato fruit. Simultaneously, the confirmation was extended to the reported tomato volatiles. The volatile extracts from field- and artificially - ripe fruits were compared qualitatively as well as quantitatively. The changes which occurred in the volatile components of the fruit at the onset of senescence also were delineated. A typical chromatogram from field-ripe tomatoes contained 60 peaks. The functional group properties of individual peaks were derived by chemical analysis. The short-chain (C3-C6) alcohols represented 10 per cent, aldehydes and ketones 32 per cent, and hydrocarbons, long-chain alcohols, and esters were in 58 per cent of the total amount of the volatiles from the field-ripe fruits. Among alcohols and carbonyls, 3-pantanol, 1-nonanal, 1-decanal, and 1-dodecanal and among esters, propyl acetate, geranyl acetate, and cetronellyl butyrate were tentatively identified as volatile compounds of tomato fruit. Linalyl acetate, citronellyl butyrate, and geranyl butyrate were identified for the first time as the components of tomato volatiles. Comparisons of volatile concentrations of field- and artificially - ripe tomatoes were made. IN the latter category of fruits the concentrations of 1-butanol, 3-pentanol, 2-methyl-3-hexanol, 3-methyl-butanal, 2,3-butanedione, propyl acetate, isopentyl butyrate, and other unidentified carbonyls were higher than those observed in the field-ripe fruits. These short-chain compounds, especially the C4-C6 moities, probably are formed in their maximum concentrations during the early stages of maturation. Under the conditions of restricted nutrient availability, sun light, and limited enzymatic activity during artificial ripening, the long-chain compounds are not sunthesized appreciably. The concentrations of some of these short-chain compounds may be to a level of masking the effects of more desirable compounds contributory to ripe tomato aroma. Notably, a pulp from the artificially ripe fruits lacked the characteristic ripe tomato aroma. The concentrations of the long-chain carbonyls and the terpene esters were low in the artificially ripe tomatoes as compared to the field-ripe ones. This may indicate major contribution of these compounds to ripe tomato aroma. An attempt has been made to theorize the mechanisms of the biogenesis of these components of tomato volatiles. The concentrations of the volatiles from field-ripe and overripe tomatoes were compared. During overripening the amounts of alcohols, aldehydes, ketones, acetates, and propionates generally decreased. However, the concentrations of diacetyl and butyric acid esters increased. It was assumed that at the onset of senescence the metabolic pathways for the formation of diacetyl and butyric acid were highly operative in tomato fruit. The mechanisms of these pathways were postulated.

wheat proteins

Organosulphur compounds

Lipid oxidation is a major challenge faced by the food industry since it causes loss of quality in lipid containing foods which results in a decrease of shelf life. In order to delay the oxidation in lipids, food industries make use of antioxidants such as EDTA (ethylene diamine tetraacetic acid), BHA (tbutyl-4-hydroxyanisole), BHT (t-butyl-4-hydroxytoluene), and TBHQ (tert-butyl-hydroxyquinone). However, these antioxidants are chemically synthesized and consumers desire simpler and cleaner labels without artificially synthesized antioxidants. Also, artificially synthesized antioxidants such as t-butyl-4-hydroxyanisole (BHA) can cause cancer in humans. Previous studies have shown that phospholipids such as phosphatidylethanolamine (PE) and phosphatidylcholine (PC) affect the activity of nonpolar antioxidants such as -tocopherol in bulk oils. PE when added to stripped soybean oil containing 100 M of -tocopherol was able to improve oxidative stability of the oil. However, PC decreased the activity of -tocopherol or had no effect. HPLC demonstrated that tocopherols were regenerated by PE which explains its synergism with - tocopherol. This study evaluated the effect of -tocopherol with varying levels of PE in stripped soybean oil. vi Additionally, antioxidant activity of -tocopherol has been shown to increase with increasing PE/PC ratio in lecithin. This study also examined the possibility of converting PC to PE in egg lecithin which will can be further used with -tocopherol. The enzyme phospholipase D was used for the conversion since it has been shown to have transphosphatidylation activity with phospholipids. The synergism of the modified lecithin with -tocopherol was analyzed in stripped soybean oil as well as in commercially refined oils. KEYWORDS: phospholipid, antioxidant, lipid oxidation, tocopherols, lecithin.

Coffee is a popular and well-loved beverage consumed worldwide by millions of people every day. While most patrons of coffee do so because of its unique and satisfying taste, consumers may be unaware of the potential beneficial health effects it also imparts. The antioxidants found in green coffee beans collectively known as chlorogenic acids (CGA) and caffeine are two of the most abundant bioactive compounds present in coffee. Both these bioactive compounds have been implicated in many studies to impart a wide range of health benefits, from reducing the risk of Type 2 diabetes, to their use as aides in weight management. Indeed, epidemiological studies on people who consume moderate amounts of coffee on a regular basis have unanimously shown benefits to overall health. While caffeine and CGA are naturally occurring compounds in coffee, their potential in conferring beneficial health effects warrant research into other potential food matrixes that can be used to bind and deliver these bioactive compounds into foods that do not naturally contain them. Milk proteins, specifically caseins, have been shown to be excellent vehicles to both bind and deliver sensitive bioactive compounds of various chemical and physical properties. Caseins have been shown in numerous studies to successfully bind to molecules such as vitamin D2, ω-3 polyunsaturated fatty acids (DHA), and iron to name a few. Because caseins exhibit high versatility in binding a variety of molecules, caseins were the milk protein of choice for the experiments in this thesis. Polyphenols have been the subject of many studies on its binding capacity with milk proteins, but research on the binding capacity of caffeine with caseins is limited. Therefore, the objectives of this thesis are threefold: 1) develop, optimize and validate an HPLC method for the accurate and simultaneous determination of caffeine and CGA, 2) establish a procedure by which caffeine and CGA bind to sodium caseinate, and 3) determine the optimal treatment conditions of pH and temperature to increase binding interactions and speculate on the mechanism of binding for each bioactive compound. A reversed phase HPLC (RP-HPLC) method was developed and subjected to validation studies with good results in linearity (caffeine R2 = 0.9992, CGA R2 = 0.9995) and precision (RSD of caffeine <1%, RSD of CGA <2%). The developed method also demonstrated selectivity for caffeine and CGA. This method was then used to analyze sodium caseinate samples containing caffeine and 5-CGA. The results from these studies have shown that binding interactions between caffeine and sodium caseinate are temperature dependent (p < 0.01) whereas binding interactions between CGA and sodium caseinate are influenced by both pH and temperature (p < 0.01). Elucidating the binding mechanisms of caffeine and CGA to sodium caseinate and providing a sensitive analytical technique by which these compounds can be accurately quantified may facilitate future research involving the use of caffeine and CGA in many other facets, as well as promoting its increased use in the dairy industry.

Polyphenol from fruits and vegetables have been proved that can lower the risk of many chronic disease. However, most studies are only focus on the extractable polyphenols right now. Non-extractable polyphenols may also have many important biological effects. The objective of this study was to find the difference between the extractable polyphenol and non-extractable by alkaline hydrolysis, acid hydrolysis and enzyme hydrolysis, compare the total phenolic content, flavonoid content and tannin content, and study their anti-inflammation effect, anti-cancer effect and antioxidant effect. The results showed that NEP alkaline hydrolysis was the best way to extract mango polyphenol. It had the highest total phenolic content and tannin content. The ORAC data also showed NEP alkaline hydrolysis had the best antioxidant effect. NEP alkaline also showed the dose-dependent inhibition manner. The extractable polyphenol showed better anti-inflammation effect then non-extractable polyphenol. Overall, we can conclude the secondary extraction did in fact yield more polyphenol from residue and non-extractable polyphenol have very similar effects as the extractable polyphenol.

No description available.

Chitosan is known to be antibacterial and antifungal, but information on its effectiveness against foodborne viruses is limited. Enteric viruses are a major concern in food safety, especially human noroviruses which are the leading cause of nonbacterial gastroenteritis. The overall goal of this research was to determine the antiviral effectiveness of chitosan. The specific objectives were to determine the effects of molecular weight (MW) and concentration of chitosan against the cultivable enteric viral surrogates, feline calicivirus (FCV-F9), murine norovirus (MNV-1), and bacteriophages (MS2 and phiX174). Purified chitosans (53, 222, 307, 421, ~1,150kDa) were dissolved in water, 1% acetic acid, or aqueous HCl (pH= 4.3), and sterilized by membrane filtration. The solutions were mixed with equal volume of virus suspension to obtain a virus titer of 5 log PFU/ml and chitosan concentration of 0.7% for all five MW and 0.7, 1.0, 1.25, and 1.5% for 53 and 222kDa. The samples were incubated for 3 hr at 37°C before viral enumeration. Controls included untreated viruses in PBS, in PBS with acetic acid, and in PBS with HCl. Chitosan showed the greatest reduction of MS2, followed by FCV-F9, phi X174, and MNV-1. A MW effect was seen with MS2, with higher MW being more efficient, and 0.7% of ~1,150kDa causing complete inactivation. Increasing the concentration of chitosan from 0.7 to 1.5% reduced the titer of MS2 and FCV-F9 by 5.16 and 2.91 logs, respectively. Although chitosan was ineffective against MNV-1, its ability to significantly reduce MS2 and FCV-F9, suggest its use for future foodborne viral control.

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Doutoramento / PhD Degree / O azeite assume em Portugal um papel importante tanto a nível económico como social. No trabalho de dissertação apresentado pretendeu-se contribuir para a melhoria e o desenvolvimento da qualidade alimentar dos azeites de Denominação de Origem Protegida de Trás-os-Montes. De entre a ampla gama de abordagens possíveis para a concretização deste objectivo, optou-se por actuar em dois domínios: 1. Caracterização da composição química do azeite e influência dos factores genéticos (cultivar). 2. Avaliação dos resíduos de pesticidas resultantes dos tratamentos fitossanitários das azeitonas e que podem estar presentes no produto final, o azeite. Desenvolveram-se e optimizaram-se diferentes métodos analíticos, baseados no uso de técnicas cromatográficas HPLC e GC, utilizando diferentes detectores (ELSD, FLD/DAD e MS/MS em HPLC e ECD/NPD, FID e MS em GC) de acordo com as especificidade das substâncias a analisar e os níveis de sensibilidade exigidos. Os parâmetros analíticos seleccionados no que concerne à caracterização e autenticidade dos azeites foram a) triacilgliceróis, b) fitosteróis esterificados e livres e c) tocoferóis e tocotrienóis. A nível de segurança desenvolveram-se metodologias para a detecção e quantificação de a) multiresíduos de pesticidas, b) fentião e seus metabolitos e c) fosmete e seus metabolitos. Na extracção das substâncias foram optimizados diversos processos (LLE, MSPD e QuEChERS), de modo a obter bons rendimentos extractivos e o menor impacte ambiental . Com base no perfil quantitativo em triacilgliceróis foi possível diferenciar azeites monovarietais das Cvs. Cobrançosa, Madural e Verdeal Transmontana. O perfil de fitosteróis esterificados e livres foi qualitativa e quantitativamente distinto entre si nos azeites DOP de Trás-os-Montes. O perfil de tocotrienóis e tocoferóis apresentou-se similar nos azeites DOP de Trás-os-Montes e nos Azeites DOP do Alto Alentejo. Nas amostras de azeitonas da Cv. Cobrançosa, colhidas em três anos consecutivos e ao longo do intervalo de segurança (7 semanas após aplicação), os teores obtidos de resíduos de pesticidas (dimetoato, fentião e fosmete) e dos seus metabolitos foram sempre muito inferiores aos LMR estabelecidos. As análises realizadas às amostras de azeites, obtidos nos três anos de estudo, resultantes de azeitonas da mesma cultivar e sujeitas às mesmas condições, apresentaram resíduos inferiores aos registados para as azeitonas. / Olive oil has an important role in Portugal, both economic and social. This research work aimed to contribute to the improvement and development of the quality of olive oils with Protected Designation of Origin from Trás-os-Montes region. Among several possibilities to accomplish this goal, the following two were chosen: 1.The characterization of chemical compounds of olive oil and the influence of genetic factors (cultivar). 2 The evaluation of pesticide residues from phytosanitarian olive treatments which may be present in the final product, olive oil. Different analytical methods were developed and optimized based on chromatographic techniques - HPLC and GC, using different detectors (ELSD, FLD/DAD and MS/MS in HPLC and ECD/NPD, FID and MS in GC) according to the specificity of the substances to analyze and to the demanded levels of sensitivity. As far as characterization and authenticity of olive oils were concerned the selected analytical parameters were a) triacylglycerols, b) esterified phytosterols and free phytosterols and c) tocopherols and tocotrienols. Regarding safety, methodologies for detection and quantification of a) multiresidue of pesticides, fenthion and its metabolits and phosmet and its metabolits were developed. For the extraction of the studied substances several procedures were enhanced (LLE, MSPD and QuEChERS), in order to achieve good extractive results and minor "environmental impact". Based on the quantitative profile of triacylglycerols it was possible to differentiate monovarietal olive oils of Cvs. Cobrançosa, Madural and Verdeal Transmontana. The profiles of esterified phytosterols and free phytosterols were qualitatively and quantitatively different in olive oils with Protected Designation of Origin from Trás-os- Montes region. The profile of tocotrienols and tocopherols proved to be similar in PDO olive oils from Trás-os-Montes and from Alto Alentejo. In olive samples of Cv. Cobrançosa, which were harvested during three consecutive years throughout the security interval (7 weeks after pesticide spraying) the levels of residual pesticides (dimetoate, fenthion and phosmet) together with its metabolits have always been significantly lower than LMR established. Analyses carried out in olive oil samples, during the three years of the research study, from the olives of the same cultivar which were exposed to the same conditions, presented an inferior level of pesticide residue compared to the pesticide residue level revealed in olives.