Current Scenario of Adsorbent Materials Used in Ethylene Scavenging Systems to Extend Fruit and Vegetable Postharvest Life

Fruit and vegetables are much appreciated by consumers due to their nutritional values and health-promoting compounds. However, different factors affect the postharvest life of such products, in where ethylene is a major one, even at low concentrations, besides temperature and relative humidity. Therefore, high attention has been focused on the development of effective tools to remove ethylene from the atmosphere surrounding these products during storage or in transit. Potassium permanganate scrubbers are one of the most used technologies to remove ethylene from horticultural products. To facilitate and improve the oxidation process, potassium permanganate has been supported onto inert solid materials of a small particle size. In this review, we aim to provide an outline of the most common materials used as potassium permanganate supports on postharvest treatment and their respective effects on quality aspects of various fresh produce during postharvest life. Vermiculite, activated alumina, zeolite, silica gel, activated carbon and clays are the most popular materials that have been used as a support of potassium permanganate-based ethylene scrubbers. The literature suggests that potassium permanganate supported onto silica gel or zeolite seems to be a promising tool to maintain fruit and vegetables quality attributes for long-term storage. Although vermiculite and activated alumina are the most commonly used materials to reach this goal, not promising results have been reported.     

Design of product as source of variance in composition of meat-based infant beikosts

The influence of both the design of the product (formulated raw ingredients) and type of product (on the meat type formulated base) on the mineral composition, crude protein (CP), protein digestibility (PD), total dietary fiber (TDF) and phytic acid (FA) contents of meat-based infant beikosts was studied. The product design was the main factor determining the CP, TDF, Ca, Na and K contents, while the type of product was the main factor determining the PD, FA, Zn, Fe and Mn contents. High K and Mn levels were related to high TDF contents. CP and Zn showed a significant relationship but the CP Fe relationship was not significant.     

Identification of oat (<Emphasis Type="Italic">Avena sativa</Emphasis>) and buckwheat (<Emphasis Type="Italic">Fagopyrum esculentum</Emphasis>) proteins and their prolamin fractions using two-dimensional polyacrylamide gel electrophoresis

Total (non-fractionated) kernel proteins and the prolamin fraction (soluble in 75% ethanol) were extracted from oat (Avena sativa) var. Flämingstern kernel and from buckwheat (Fagopyrum esculentum) var. Kora kernel. As for buckwheat, extraction was effective only after kernel dehulling which allowed the removal of tannins and phenolic compounds that form complexes with proteins during extraction. The extracted proteins were analyzed using two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). Gels of the prolamin fractions of oat and buckwheat were used as reference gels in order to detect prolamins on gels of total kernel proteins. The occurrence of 26 and 29 spots corresponding to prolamins was found on gels of total oat proteins and on gels of total buckwheat proteins, respectively. The electrophoretic images of oat and buckwheat prolamins revealed organized subregions containing spots with similar isoelectric points (pI) and various molecular weights (MW), mostly on oat prolamin gels and spots of similar molecular weights with various isoelectric points, mostly on buckwheat prolamin gels. Such organized subregions can be used as identifiers for the occurrence of prolamin fractions in total proteins (particularly as regards buckwheat proteins).     

A filtration-based real-time PCR method for the quantitative detection of viable Salmonella enterica and Listeria monocytogenes in food samples

We developed a novel filtration-based method that can eliminate dead or severally damaged Salmonella enterica and Listeria monocytogenes in food samples. This new method can recover all viable bacteria in less than 30 min, and can be coupled with a subsequent bacterial DNA extraction and real-time PCR. No statically significant differences (p < 0.01) were found between real-time PCR results obtained separately from S. enterica and L. monocytogenes when different ratios of living and dead cells were used. The analytical sensitivity in both cases was 1 genome equivalent (GE), and the quantification was linear (R² > 0.9969) over a 5-log dynamic range with PCR efficiencies >0.9754. When compared with the standard microbiological methods for the detection of these foodborne pathogens, the relative accuracy was excellent ranging from 95.72% to 104.48%. Finally, we applied the pre-treatment method to the direct detection of viable forms of these foodborne pathogens in food samples using yogurt as a model, the results being similar to those obtained using pure cultures.     

Studies on the role and mode of operation of the very-lysine-rich histones in eukaryote chromatin. Nuclear-magnetic-resonance studies on nucleoprotein and histone phi 1-DNA complexes from marine invertebrate sperm

Proton magnetic resonance and other measurements have been carried out in order to study the behaviour of the lysine-rich histones phi 1 in the sperm chromatin of certain marine invertebrates. Well defined particles (12 S) have been obtained from this chromatin by nuclease treatment. Chromatin solubility as a function of ionic strength shows a relaxation at salt concentrations higher than in the case of calf thymus nucleoprotein. Nuclear magnetic resonance (NMR) studies show that the release of histone from DNA occurs both in chromatin and in the reconstituted complexes at practically the same ionic strength as solubility relaxation. The higher the arginine content of a given phi 1, the higher the ionic strength at which both effects take place. The NMR results demonstrate that arginine residues are bound more strongly than lysine residues. The data overall show that phi 1 histones play a role in the contraction mechanism of sperm chromatin similar to that of H 1 histone in calf thymus chromatin. The highly contracted state of sperm chromatin is directly related to the increased arginine content of the phi 1 histone.     

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.