Food Chemistry

Determination of eighty-one volatile organic compounds in dietary Rumex induratus leaves by GC/IT-MS, using different extractive techniques

by Marcos Taveira

Screening of Antioxidant Compounds During Sprouting of Brassica oleracea L. var. costata DC

by Marcos Taveira

Brassica oleracea var. costata : comparative study on organic acids and biomass production with other cabbage varieties

by Marcos Taveira

Screening of Antioxidant Phenolic Compounds Produced by In Vitro Shoots of Brassica oleracea L. var. costata DC

by Marcos Taveira

Evolution of Brassica rapa var. rapa L. volatile composition by HS-SPME and GC/IT-MS

by Marcos Taveira

Inflorescences of Brassicacea species as source of bioactive compounds: A comparative study

by Marcos Taveira

High-performance liquid chromatography-diode array detection-electrospray ionization multi-stage mass spectrometric screening of an insect/plant system: the case of Spodoptera littoralis/Lycopersicon esculentum phenolics and alkaloids

by Marcos Taveira

In Vitro Cultures of Brassica oleracea L. var. costata DC: Potential Plant Bioreactor for Antioxidant Phenolic Compounds

by Marcos Taveira

Tomato (Lycopersicon esculentum) Seeds: New Flavonols and Cytotoxic Effect

by Marcos Taveira

Combined effects of aqueous chlorine dioxide and ultrasonic treatments on postharvest storage quality of plum fruit (Prunus salicina L.)

by Zhao Chen

The individual and combined effects of aqueous chlorine dioxide (40mg L−1 ClO2 for 10min) and ultrasonic (100W... more The individual and combined effects of aqueous chlorine dioxide (40mg L−1 ClO2 for 10min) and ultrasonic (100W ultrasound for 10min) treatments on postharvest storage quality of plum fruit (Prunus salicina L.) were investigated. Two combination modes of these two treatments, treatment with ClO2 solution accompanied by simultaneous ultrasonic waves (one-step mode) and applying them sequentially (two-stepmode)were adopted. The effect of combined treatments onmaintaining contents of total flavonoids, ascorbic acid, reducing sugars, and titratable acidswere similar butweremore beneficial than the individual treatments and the untreated control. The one-step mode was more effective in reducing the initial microflora and retaining sensory qualities of plum fruit than the two-step mode, and fruit shelf-life could be extended to 60 d compared to 35 d for the control.Moreover, therewere no detectable chemical residues in the treated samples with the one-step mode. These results demonstrated that the combined treatments of ClO2 and ultrasound could be a promising approach to maintain postharvest storage quality of plum fruit without significant risks to consumers.

Effects of aqueous chlorine dioxide treatment on enzymatic browning and shelf-life of fresh-cut asparagus lettuce (Lactuca sativa L.)

by Zhao Chen

Effects of aqueous chlorine dioxide (ClO2) treatment on enzymatic browning and shelf-life of fresh-cut asparagus... more Effects of aqueous chlorine dioxide (ClO2) treatment on enzymatic browning and shelf-life of fresh-cut asparagus lettuce (Lactuca sativa L. var. angustana) were investigated. Fresh-cut asparagus lettuce was treated at different concentrations (10, 40, and 100 mg L-1) for different times (5, 10, and 20 min). Following treatments, lettuce slices were stored at 4 ℃ for 14 days. The activities of polyphenol oxidase (PPO) and peroxidase (POD) in the lettuce were reduced by ClO2. Meanwhile, the degradation of color in the ClO2 treated lettuce was also delayed. It was concluded that ClO2 concentration and treatment time were two significant factors affecting ClO2 treatment on enzymatic browning of fresh-cut asparagus lettuce (P < 0.05). From the microbiological and sensory quality perspectives, the treatment with 100 mg L-1 ClO2 for 20 min could prolong the shelf-life to 14 days compared to 4 days for the control. These results indicated that ClO2 treatment was a promising approach to inhibit enzymatic browning and prolong shelf-life of fresh-cut asparagus lettuce.

Effects of aqueous chlorine dioxide treatment on nutritional components and shelf-life of mulberry fruit (Morus alba L.)

by Zhao Chen

Effects of aqueous chlorine dioxide (ClO2) treatment on nutritional components and shelf-life of mulberry fruit (Morus... more Effects of aqueous chlorine dioxide (ClO2) treatment on nutritional components and shelf-life of mulberry fruit (Morus alba L.) were investigated. Mulberry fruit were immersed into 20, 60, and 80 mg/L ClO2 solutions for 5, 10, and 15 min, respectively. Mulberries were then rinsed with potable tap water for 1 min and stored at -1 ºC for 14 d. ClO2 treatment was effective in retention of flavonoid, ascorbic acid, reducing sugar, and titratable acid. ClO2 concentration and treatment time were significant factors affecting ClO2 treatment. The shelf-life of the samples treated by 60 mg/L ClO2 for 15 min was extended to 14 d compared to 8 d for the control. No ClO2, ClO2-, or ClO3- residues were detected in samples treated by 60 mg/L ClO2 for 15 min. These results indicated that ClO2 treatment was a promising approach to preserve mulberry fruit with no significant risks of chemical residues.

Fish Bone Chemistry and Ultrastructure: Implications for Taphonomy and Stable Isotope Analysis

by Paul Szpak

Szpak, P. 2011. Fish Bone Chemistry and Ultrastructure: Implications for Taphonomy and Stable Isotope Analysis. Journal of Archaeological Science 38, 3358-3372.

Abstract
This paper reviews the ultrastructure and chemistry of fish bone, with an emphasis on zooarchaeology and... more Abstract
This paper reviews the ultrastructure and chemistry of fish bone, with an emphasis on zooarchaeology and stable isotope analysis. On the basis of the chemical composition of the collagen and the relationships between the collagen and mineral phases, fish bone is more susceptible to biotic and abiotic degradation than mammalian bone and is therefore less likely to be recovered in archaeological deposits. The amino acid composition of fish bone differs from that of mammals (and other taxonomic groups), most notably with respect to hydroxyproline content. The C:N ratio of fish collagen, however, is very similar and slightly lower than mammalian collagen, and thus the traditional range of acceptable C:N ratios for collagen (2.9−3.6) should not be shifted or extended for fish on the basis of the amino acid composition of collagen. An extensive survey of published archaeological bone collagen C:N ratios demonstrates that fish collagen from archaeological contexts tends to have significantly higher C:N ratios than mammalian collagen. The elevated C:N ratios in fish bone collagen may be the result of abiotic degradation processes that occur within the bone after death, the presence of exogenous humic contaminants, or endogenous lipid contaminants.

A review of antihypertensive and antioxidant activity found in macroalgae

by Anna K Croft

M. Tierney, A. K. Croft and M. Hayes, Bot. Mar., 387-408, 53(5), 2010

There has been a significant increase in the occurrence of chronic diseases caused by oxidative stress and... more There has been a significant increase in the occurrence of chronic diseases caused by oxidative stress and hypertension in recent decades. Hypertension is a sustained increase in blood pressure and is a controllable risk factor in the development of a number of cardiovascular diseases such as stroke and coronary infarction. As a result, the number of investigations aimed at identification of dietary compounds from natural sources that may be effective in treating such diseases has increased. Macroalgae, also known as seaweeds or sea vegetables, have been traditionally
incorporated into Pacific and Asian foods for hundreds of years and have recently become a popular addition to some Western diets. Macroalgae are classified into three higher taxa according to their pigmentation and they are brown (Class Phaeophyceae), green (Phylum Chlorophyta) and red (Phylum Rhodophyta).
Due to the harsh environments in which many macroalgae exist, they have developed effective defence mechanisms and, as a result, are a rich source of bioactive compounds, including polysaccharides, polyphenols, fatty acids and peptides, with different structures and activities from those found in terrestrial plants. This review explores the potential use of macroalgal species as bioactive ingredients that may be incorporated into functional foods for use in the prevention and/or treatment of hypertension and oxidative stress related diseases.

“Improving the Flavour Acceptability of Recombined Milk Blended with Fresh Milk” Le Lait, France (1986) 66(3), pp 305-306

by DR. RAKESH MOHAN JOSHI

“Influence of Stabilising Salts on the Viscosity of Recombined Milk Blended with Fresh Milk”, Japanese Journal of Dairy and Food Science, Japan (1987) 36 (1) A, pp. 21.23

by DR. RAKESH MOHAN JOSHI

Towards the electrochemical quantification of the strength of garlic

by Leigh Aldous

Benjamin C. M. Martindale, Leigh Aldous, Neil V. Rees and Richard G. Compton, Analyst, 2011, 136(1), 128 -133

http://dx.doi.org/10.1039/C0AN00706D

A simple but sensitive technique has been demonstrated towards the electroanalytical quantification of the strength of... more A simple but sensitive technique has been demonstrated towards the electroanalytical quantification of the strength of garlic. This technique can also be used to quantify dialkyldisulfides. The cyclic voltammetry of bromide was found to be a sensitive electrochemical probe, electrogenerated bromine reacting with dialkyldisulfides to catalytically regenerate bromide, resulting in a significant increase in peak current. A linear response of current vs. concentration was observed between 0.1 and 15 mM dipropyldisulfide at edge plane pyrolytic graphite (EPPG) electrodes; a smaller range up to ca. 5 mM was available at screen printed carbon electrodes (SPCEs), with a detection limit (from 3 sigma) of 0.067 mM. The response of diallyldisulfide was found to be essentially identical. Shaking garlic puree in acetonitrile for 5 minutes, followed by dilution with water then recording the voltammetry at the cheap, disposable SPCE gave a linear trend in current with respect to the quantity of garlic present, corresponding to the diallyldisulfide extracted. This has potential applications in monitoring the garlic content of medicinal supplements, batch-to-batch variation and the stability of garlic during storage.

http://dx.doi.org/10.1039/C0AN00706D

Madeira wine ageing prediction based on different analytical techniques: UV–vis,GC-MS, HPLC-DAD

by Jose Carlos Marques

, Ana C. Pereira, Marco S. Reis, Pedro M. Saraiva, José C. Marques; Chemometrics and Intelligent Laboratory Systems xxx (2010) xxx–xxx, published on line

The present work aims to analyze the feasibility of different analytical measurement procedures for Madeira wine... more The present work aims to analyze the feasibility of different analytical measurement procedures for Madeira wine ageing prediction. In order to properly identify and quantify the chemical compounds qualified for characterizing wine evolution during the ageing period, chromatographic and spectroscopic analyses were carried out. Twenty-six samples, representative of ten harvest years and covering an ageing period of 20 years, were analyzed in terms of their volatile and phenolic composition, as well as characterized in terms of absorbance measurements in the UV and Visible region. Then, multivariate prediction models were established by applying PLS regression to each chemical data set, after which they were compared in terms of their ageing prediction ability. The optimum number of PLS dimensions to consider in each estimated model was obtained based on the minimization of the root mean squared error of Monte Carlo validation. With such estimated models, the prediction interval estimates based on the bootstrap percentile approach were also computed for the available samples, in order to test model's prediction ability, once each sample is successively removed from the data set.

Our analysis shows that Madeira wine age, produced from a known grape variety, can be predicted with good accuracy from its volatile and phenolic composition, as well as from UV–vis absorbance measurements. The PLS models estimated are able to predict wine age with a root mean square error of 0.9, 1.1, and 1.4 years, respectively. The sample-specific prediction intervals computed also allowed for the analysis of differences between observed and predicted values, and confirmed the interesting wine age prediction abilities of the proposed methodologies. A compromise between model accuracy and cost of analysis can be established in order to decide which methodology to use, according to the particular application scenario, as the more time-consuming and complex techniques (GC-MS and HPLC-DAD) are also those leading to more accurate results, but UV–vis also enabled us to come up with acceptable age predictions.

Evaluation of the feasibility of the electronic tongue as a rapid analytical tool for wine age prediction and quantification of the organic acids and phenolic compounds. The case-study of Madeira wine

by Jose Carlos Marques

A. Rudnitskaya, S.M. Rocha, A. Legin, V. Pereira, J.C. Marques; Analytica Chimica Acta 662 (2010) 82–89

A set of fourteen Madeira wines comprising wines produced from four Vitis vinifera L. varieties (Bual, Malvasia,... more A set of fourteen Madeira wines comprising wines produced from four Vitis vinifera L. varieties (Bual, Malvasia, Verdelho and Tinta Negra Mole) that were 3, 6, 10 and 17 years old was analysed using HPLC and an electronic tongue (ET) multisensor system. Concentrations of 24 organic acids, phenolic and furanic compounds were determined by HPLC. The ET consisting of 26 potentiometric chemical sensors with plasticized PVC and chalcogenide glass membranes was used. Significance of the effects of age and variety on the ET response and wine composition with respect to the organic acids, phenolics and furanic derivatives were evaluated using ANOVA—Simultaneous Component Analysis (ASCA). Significance of the effects was estimated using a permutation test (1000 permutations). It was found that effects of age, grape variety and their interaction were significant for the HPLC data set and only the effect of age was significant for the ET data. Calibration models of the HPLC and ET data with respect to the wine age and of the ET data with respect to the concentration of the organic acids and phenolics were calculated using PLS1 regression. Models were validated using cross-validation. It was possible to predict wine age from HPLC and ET data with the accuracy in cross-validation of 2.6 and 1.8 years respectively. The ET was capable of detecting the following components (mean relative error in cross-validation is shown in the parentheses): tartaric (8%), citric (5%), formic (12%), protocatehuic (5%), vanillic (18%) and sinapic (14%) acids, catechin (6%), vanillin (12%) and trans-resveratrol (5%). The ET capability of predicting Madeira wine age with good accuracy (1.8 years) as well as quantify of some organic acids and phenolic compounds was demonstrated.

HPLC-DAD methodology for the quantification of organic acids, furans and polyphenols by direct injection of wine samples

by Jose Carlos Marques

Vanda Pereira, José S. Câmara, Juan Cacho, José C. Marques

This article proposes a simple and sensitive HPLC method with photo-diode array detection for the analysis of organic... more This article proposes a simple and sensitive HPLC method with photo-diode array detection for the analysis of organic acids, monomeric polyphenols and furanic compounds in wine samples by direct injection. The chromatographic separation of 8 organic acids, 2 furans and 22 phenolic compounds was carried out with a buffered solution (pH 2.70) and acetonitrile as mobile phases and a difunctionally bonded C18 stationary phase, Atlantis dC18 (250×4.6 mm, 5 m) column. The elution was performed in 12 min for the organic acids and in 60 min for the phenolic compounds, including phenolic acids, stilbenes and flavonoids. Target compounds were detected at 210 nm (organic acids, flavan-3-ols and benzoic acids), 254 nm (ellagic acid), 280 nm (furans and cinnamic acid), 315 nm (hydroxycinnamic acids and trans-resveratrol) and 360 nm (flavonoids). The RSD for the repeatability test (n=5) of peak area and retention times were below 3.1 and 0.3%, respectively, for phenolics and below 1.0 and 0.2% for organic acids. The RSDs expressing the reproducibility of the method were higher than for the repeatability results but all below 9.0%. Method accuracy was evaluated by the recovery results, with averaged values between 80 and 104% for polyphenols and 97-105% for organic acids. The calibration curves, obtained by triplicate injection of standard solutions, showed good linearity with regression coefficients higher than 0.9982 for polyphenols and 0.9997 for organic acids. The LOD was in the range of 0.07-0.49 mg/L for polyphenols (cinnamic and gallic acids, respectively) and 0.001-0.046 g/L for organic acids (oxalic and lactic acids, respectively). The method was successfully used to measure and assess the polyphenolic fingerprint and organic acids profile of red, white, rosé and fortified wines.