Effects of Fish Gelatin and Tea Polyphenol Coating on the Spoilage and Degradation of Myofibril in Fish Fillet During Cold Storage

Fish fillet is easily spoiled during storage. Antimicrobial edible coating of gelatin extracted from fish skins and bones and tea polyphenol (TP) was developed to inhibit the spoilage of fish fillet during cold storage. For coating containing 0.4 % TP and 1.2 % gelatin, the pH only slightly increased from 6.17 at day 0 to 6.32 at day 17 of cold storage, while the pH of control coating increased to 6.87 at day 17. Atomic force spectrometry was used to analyse the nanostructure of myofibril, which is the major component of fish muscle. The results showed that the length of myofibril from 0.4 % TP and 1.2 % gelatin group was greater than 15 μm, while the diameter and height were 3.38 and 0.59 μm, respectively, which exhibited the most intact nanostructure after 17 days of cold storage. Meanwhile, matrix-assisted laser desorption–ionisation–time-of-flight mass spectrometry result showed that TP delayed the degradation of myosin light chain 3 and troponin T in myofibril. Gas chromatography–mass spectrometry of volatile organic compounds (VOCs) also showed that 0.4 % TP and 1.2 % gelatin coating group had minimal production of spoilage markers, such as 1-octen-3-ol, 2-methyl propanoic acid and dimethyl sulfide. The microbial analysis showed that the aerobic mesophilic/psychrotrophic count, yeasts and moulds of 0.4 % TP and 1.2 % gelatin group were significantly lower than the control group. Therefore, 0.4 % TP and 1.2 % gelatin coating showed the best antimicrobial effect and can be used to maintain the nanostructure of fish fillet and prevent the spoilage during cold storage.     

Validation of a Single-Extraction Procedure for Sequential Analysis of Vitamin E, Cholesterol, Fatty Acids, and Total Fat in Seafood

Food lipid major components are usually analyzed by individual methodologies using diverse extractive procedures for each class. A simple and fast extractive procedure was devised for the sequential analysis of vitamin E, cholesterol, fatty acids, and total fat estimation in seafood, reducing analyses time and organic solvent consumption. Several liquid/liquid-based extractive methodologies using chlorinated and non-chlorinated organic solvents were tested. The extract obtained is used for vitamin E quantification (normal-phase HPLC with fluorescence detection), total cholesterol (normal-phase HPLC with UV detection), fatty acid profile, and total fat estimation (GC-FID), all accomplished in <40 min. The final methodology presents an adequate linearity range and sensitivity for tocopherol and cholesterol, with intra- and inter-day precisions (RSD) from 3 to 11 % for all the components. The developed methodology was applied to diverse seafood samples with positive outcomes, making it a very attractive technique for routine analyses in standard equipped laboratories in the food quality control field.     

Dispersive Liquid–Liquid Microextraction Followed by Capillary High-Performance Liquid Chromatography for the Determination of Six Sulfonylurea Herbicides in Fruit Juices

In this study a simple, rapid, and efficient method has been developed for the determination of six sulfonylurea herbicides (SUHs): triasulfuron, metsulfuron-methyl, chlorsulfuron, flazasulfuron, chlorimuron-ethyl, and primisulfuron-methyl in commercial grape and apple juice samples, using dispersive liquid–liquid microextraction coupled with capillary high-performance liquid chromatography with diode array detection. Various parameters that influence the extraction efficiency, such as the type and volume of extraction and disperser solvents, sample pH, and salt addition, were investigated and optimized. Under the optimum conditions, limits of detection and quantification of the method were in the ranges of 2–9 and 8–29 μg L^?1, respectively, lower than the maximum residue limits set by the European Union for the raw fruits, such as grape and apple. The intra- and inter-day relative standard deviations varied from 1.0 to 8.2 and 1.8 to 9.8 %, respectively, with recoveries between 72.0 and 109.5 % for commercial grape (both white and red) and apple juice samples, showing satisfactory accuracy for the determination of SUHs in fruit juices.     

Scale-up of the production of cassava starch based films using tape-casting

Most research on biodegradable and edible films uses the well-known casting technique, which allows the preparation of films of small dimensions. Besides, cassava starch films prepared by extrusion processes do not have good properties, because of the high shear rates applied. The tape-casting technique allows the spreading of a suspension on large supports, with the control of the thickness by an adjustable blade at the bottom of the spreading device. The drying of the film can be carried-out on the support itself, under controlled conditions. Film-forming suspensions with different formulations were prepared, varying the concentrations of starch (3 and 5 g/100 g of suspension), glycerol (0.20 and 0.25 g/g of starch) and cellulose fibers (0 and 0.30 g/g of starch) and used to produce films by tape-casting. The results showed that tape-casting is a suitable technology to scale-up the production of starch based films.     

Rapid virus detection procedure for molecular tracing of shellfish associated with disease outbreaks

Detection of pathogenic viruses in oysters implicated in gastroenteritis outbreaks is often hampered by time-consuming, specialist virus extraction methods. Five virus RNA extraction methods were evaluated with respect to performance characteristics and sensitivity on artificially contaminated oyster digestive glands. The two most promising procedures were further evaluated on bioaccumulated and naturally contaminated oysters. The most efficient method was used to trace the source in an outbreak situation. Out of five RNA extraction protocols, PEG precipitation and the RNeasy Kit performed best with norovirus genogroup III-spiked digestive glands. Analyzing 24-h bioaccumulated oysters revealed a slightly better sensitivity with PEG precipitation, but the RNeasy Kit was less prone to concentrate inhibitors. The latter procedure demonstrated the presence of human noroviruses in naturally contaminated oysters and oysters implicated in an outbreak. In this outbreak, in four out of nine individually analyzed digestive glands, norovirus was detected. In one of the oysters and in one of the fecal samples of the clinical cases, identical norovirus strains were detected. A standard and rapid virus extraction method using the RNeasy Kit appeared to be most useful in tracing shellfish as the source in gastroenteritis outbreaks, and to be able to make effective and timely risk management decisions.     

Bending performance of 3-layer beech (Fagus sylvativa L.) and Norway spruce (Picea abies (L.) Karst.) VTC composites bonded with phenol–formaldehyde adhesive and liquefied wood

Low quality beech (Fagus sylvatica L.) and Norway spruce (Picea abies (L.) Karst.) were densified with viscoelastic thermal compression (VTC) process to two different degrees of densification, and lamellas were used to manufacture different types of 3-layer VTC composites. Bending properties of 3-layer VTC composites bonded with phenol formaldehyde (PF) adhesive and liquefied wood (LW) were determined and compared to 3-layer composites produced with undensified beech or spruce wood lamellas. Morphology of VTC spruce wood of higher density was analysed with fluorescent microscopic technique. All composites produced with densified beech lamellas and bonded with PF adhesive had significantly higher values of modulus of rupture (MOR) and modulus of elasticity (MOE) than composites produced with undensified lamellas. Densified spruce lamellas contributed to better bending performance of 3-layer VTC composites bonded with PF adhesive to some extent. Furthermore, composites bonded with LW had significantly lower MOR and MOE values compared to composites bonded with PF adhesive. Study of VTC spruce wood microstructure showed that densification caused non-uniform deformation of cell wall structure, in which cell wall fractures were observed.     

Biocomposite Films Based on κ-Carrageenan/Locust Bean Gum Blends and Clays: Physical and Antimicrobial Properties

The aims of this work were to evaluate the physical and antimicrobial properties of biodegradable films composed of mixtures of κ-carrageenan (κ-car) and locust bean gum (LBG) when organically modified clay Cloisite 30B (C30B) was dispersed in the biopolymer matrix. Film-forming solutions were prepared by adding C30B (ranging from 0 to 16 wt.%) into the κ-car/LBG solution (40/60 wt.%) with 0.3 % (w/v) of glycerol. Barrier properties (water vapour permeability, P _vapour; CO₂ and O₂ permeabilities), mechanical properties (tensile strength, TS, and elongation-at-break, EB) and thermal stability of the resulting films were determined and related with the incorporation of C30B. Also, X-ray diffraction (XRD) was done in order to investigate the effect of C30B in film structure. Antimicrobial effects of these films against Listeria monocytogenes, Escherichia coli and Salmonella enterica were also evaluated. The increase of clay concentration causes a decrease of P _vapour (from 5.34?×?10^?11 to 3.19?×?10^?11 g (m s?Pa)^?1) and an increase of the CO₂ permeability (from 2.26?×?10^?14 to 2.91?×?10^?14 g (m s?Pa)^?1) and did not changed significantly the O₂ permeability for films with 0 and 16 wt.% C30B, respectively. Films with 16 wt.% clay exhibited the highest values of TS (33.82 MPa) and EB (29.82 %). XRD patterns of the films indicated that a degree of exfoliation is attained depending on clay concentration. κ-car/LBG–C30B films exhibited an inhibitory effect only against L. monocytogenes. κ-car/LBG–C30B composite films are a promising alternative to synthetic films in order to improve the shelf life and safety of food products.     

Comparison of Different Extraction Methods to Determine Phenolic Compounds in Virgin Olive Oil

A comparison between different extraction methods has been performed in order to assess their effectiveness for the analysis of total phenols (liquid–liquid extraction (LLE), liquid–liquid micro extraction (LLME), and ultrasound liquid–liquid extraction (USE)) and individual phenols (LLME, USE, and solid-phase extraction (SPE)) from virgin olive oil (VOO). Statistical analysis of the analytical data obtained for the total phenol content of a VOO, showed that LLME and USE can represent a reliable alternative to the traditional procedure based on LLE that needs more amount of sample, generates more wastes, and is more time consuming. When an olive oil spiked with phenols was used to test the efficiency of LLME, USE, and SPE methods, the statistical analysis of the data obtained for each individual phenol, again proved LLME and USE methods to be the most suitable, in terms of precision and recoveries, for this purpose. The analysis of real samples (Arbequina and Picual cultivars) confirmed the results obtained for the spiked oil.     

Effect of Butternut (Cucurbita moschata Duchesne ex Poiret) Fibres on Bread Making, Quality and Staling

The effect of different enriched fibre products obtained from butternut (Cucurbita moschata Duchesne ex Poiret) on bread making and bread quality was evaluated through the study of bread yield, quality parameters (specific volume, crumb firmness, crumb and crust colour) and bread shelf life. Fractions tested were obtained from butternut mesocarp through ethanolic treatment (fraction AIR) or through dehydration (fraction S) or from the ethanolic treatment of peel (fraction C). These fractions were incorporated in a bread formula, at levels of 5, 10 and 15 g of fibre fraction per kilogram of wheat flour. The study of crumb through digital imaging and thermal analysis was also performed in order to better understand the effects observed. An important influence of water absorption kinetics and chemical composition of the fibre fractions studied was observed in the results obtained. Lower bread firmness was determined 24 h after baking when 10 g of C or either 10 or 15 g of S was present per kilogram of wheat flour used. Breads made with flour containing 10–15 g of S or 5 g of C per kilogram of wheat flour tended to be softer, while 10 g of C per kilogram of flour produced significantly softer breads along 9 days storage.     

Application of Matrix Solid-Phase Dispersion and Liquid Chromatography–Ion Trap Mass Spectrometry for the Analysis of Pesticide Residues in Fruits

This study presents an application of rapid and sensitive multiresidue method for the analysis of acephate, acetamipride, atrazine, carbendazim, carbaryl, carbofuran, dimethoate, imidacloprid, linuron, malathion, monocrotophos, monuron, propazine, simazine, and tebufenozide in fruits. The method involves an extraction procedure based on matrix solid-phase dispersion using diatomaceous earth as a dispersant and dichloromethane as the eluent. The target pesticides were determined using liquid chromatography–ion trap mass spectrometry. Quantification of the analytes was carried out using the most sensitive ion transition. Ion trap parameters, like activation q and time, were found to have a prominent influence on method sensitivity for some pesticides and they were optimized accordingly. The confirmation of residues detected in real samples was performed by repeated injection and acquiring additional ion transitions besides the ones used for quantification. The method was validated for accuracy, linearity, reproducibility, and sensitivity. Mean values for recoveries were in the range of 70–120 % for all tested matrices. Repeatability of the method, expressed as the relative standard deviation, was in general lower than 20 %. The applicability of the method to routine analysis was tested in real fruit samples with good performance.