Phylogenetic analyses and toxigenic profiles of Fusarium equiseti and Fusarium acuminatum isolated from cereals from Southern Europe

Fusarium equiseti and Fusarium acuminatum are toxigenic species that contaminate cereal crops from diverse climatic regions. They are common in Spanish cereals. The information available on their phylogenetics and toxigenic profiles is, however, insufficient to assist risk evaluation. In this work, phylogenetic analyses were performed using partial sequences of the translation elongation factor gene (EF-1α) of F. equiseti and F. acuminatum strains isolated from barley and wheat from Spain and other countries. The Northern and Southern European F. equiseti strains largely separated into two phylogenetically distinct clusters. This suggests the existence of two distinct populations within this species, explaining its presence in these regions of markedly different climate. Production of type A and B trichothecenes by the Spanish strains, examined in wheat cultures using a multitoxin analytical method, indicated that F. equiseti could produce deoxynivalenol and nivalenol and other trichothecenes, at concentrations that might represent a significant risk of toxin contamination for Southern European cereals. F. acuminatum showed low intraspecific genetic variability and 58% of the strains could produce deoxynivalenol at low level. Neither species was found to produce T-2 or HT-2 toxins. The present results provide important phylogenetic and toxigenic information essential for the accurate prediction of toxigenic risk.     

Lactobacillus casei strains isolated from cheese reduce biogenic amine accumulation in an experimental model

Tyramine and histamine are the biogenic amines (BAs) most commonly found in cheese, in which they appear as a result of the microbial enzymatic decarboxylation of tyrosine and histidine respectively. Given their toxic effects, their presence in high concentrations in foods should be avoided. In this work, samples of three cheeses (Zamorano, Cabrales and Emmental) with long ripening periods, and that often have high BA concentrations, were screened for the presence of BA-degrading lactic acid bacteria (LAB). Seventeen isolates were found that were able to degrade tyramine and histamine in broth culture. All 17 isolates were identified by 16S rRNA sequencing as belonging to Lactobacillus casei. They were typed by plasmid S1-PFGE and genomic macrorestriction-PFGE analysis. Two strains (L. casei 4a and 5b) associated with high degradation rates for both BAs were selected to test how this ability might affect histamine and tyramine accumulation in a Cabrales-like mini-cheese manufacturing model. The quantification of BAs and the monitoring of the strains' growth over ripening were undertaken by RP-HPLC and qPCR respectively. Both strains were found to reduce histamine and tyramine accumulation. These two strains might be suitable for use as adjunct cultures for reducing the presence of BAs in cheese.     

Description of the kinetic enzymatic browning in banana (Musa cavendish) slices using non-uniform color information from digital images

A novel methodology “fractal browning indicator” (FBI) is presented, that describes the enzymatic browning kinetic based on the use of irregular color patterns from banana slice images. It uses the fractal Fourier texture image value in a selected area, to calculate a fractal dimension (FD), which represents the complexity of color distribution. During the procedure, colors from digital images were first transformed to L^*a^*b^* space color using a transformation function (quadratic model), in order to derivate three color channels, lightness (L^*), redness (a^*), and yellowness (b^*). In the results, lightness and yellowness parameters decreased during the browning kinetic, when their respective FD values increased, indicating major color distribution complexity in a selected area analyzed during the kinetic. The redness color (a^*) did not show any statistical variation. The empirical power law model was suitable to correlate enzymatic browning kinetic data both for FBI and for the traditional method (when an L^* mean was used). However, enzymatic browning rates using the FBI method, were between 8.5 and 35 times higher than rates calculated with the traditional method.     

Apparent chemical composition of nine commercial or semi-commercial whey protein concentrates, isolates and fractions

Summary Analytical results are given for whey powders prepared on a commercial or semi-commercial scale by three companies. Altogether, five preparations enriched in β-lactoglobulin, four whey protein isolates and a fraction enriched in α-lactalbumin were analyzed for protein composition, including %β-lactoglobulin, α-lactalbumin, bovine serum albumin, casein (glyco) macropeptide and the main triglycerides. Protein composition was determined by high pressure gel permeation and reversed phase liquid chromatography and by capillary zone electrophoresis. The extent of modification of the native β-lactoglobulin structure was also measured through the degree of lactosylation and the fraction of accessible free sulphydryl groups. One significant finding was that the calculated recovery of protein following quantitation of the chromatogram or electropherogram was seldom above 90% and occasionally below 60% of that loaded onto the column or capillary, raising doubts as to the reliability of the analytical results. Extrapolation by linear regression to 100% recovery allowed estimates to be made of the true β-lactoglobulin composition of the samples. The nine samples could be placed into three distinct groups with estimated true β-lactoglobulin weight % of 70.9 ± 1.1, 62.0 ± 3.4 and 39.5 ± 4.9. Physico-chemical properties of the group of samples are reported elsewhere (Holt et al ., 1999).     

Comparison of seven methods for stored cereal losses to insects for their application in rural conditions

There are several methods for assessing harvest losses during storage with varying degrees of accuracy, reliability and practical application, however, field conditions may limit their use among subsistence farmers and traders in developing nations. We compared seven standard grain loss methods during natural and controlled infestation by Sitophilus oryzae L. in wheat and barley to select the best procedures for use in farm storage. Methods tested were: 1) visual inspection of infested lots, 2) uncorrected weight loss, 3) modified standard volume/weight ratio, 4) grain count and weight, 5) percentage of damaged grains converted to weight loss, 6) one thousand grain mass, and 7) one thousand grain mass including dust. Previously disinfested cereal lots (wheat, barley, 500 g fresh w) were exposed to 20 newly emerged adult S. oryzae for 90 d at 28 °C and 70% r.h. Naturally- infested wheat lots were also monitored under the same conditions. Before and after this period, fresh and dry weight, number, moisture content of uninfested and damaged grains, weight of 1 L of seeds and dust produced by insect activity, fresh and dry weight of 1000 kernels, and number of adult weevils was determined and applied to appropriate equations of methods (1), (2), (3), (4), (5), (6) and (7). Grain mass loss estimations varied by wide margins (9.3 ± 1.3% to 25.8 ± 2.3% in barley, 2.2 ± 0.7% to 12.5 ± 2.5% in wheat) depending on method employed, suggesting the need for careful selection of the most appropriate procedure under field conditions and farmer/trader interests. While accurate procedures such as method 7 provided dependable results, methods 3 and 5 appear most practical for wheat and barley.     

Adverse effects of pharmacological therapy for nicotine addiction in smokers following a smoking cessation program.

This multicenter, community-based, prospective, longitudinal study evaluated the safety of nicotine replacement therapy (NRT), bupropion, and combined therapy of NRT and bupropion for smokers seeking to quit, when these therapies were used under real-world conditions following a smoking cessation program. Participants were smokers aged 18 years or older who attended five smoking cessation clinics. Evaluations were made at 15, 30, 60, and 90 days. We investigated the possible existence of adverse effects as well as the severity of each adverse effect and its influence on the treatment course. The study included 904 smokers: 370 received NRT, 413 received bupropion, and 121 received combined therapy. At 15, 30, 60, and 90 days, adverse effects were reported by 43.8%, 33.1%, 22.3%, and 5.7% of subjects, respectively. Adverse effects were significantly more frequent in subjects receiving combined therapy or bupropion alone than in NRT-treated subjects at the 15-, 30-, and 60-day follow-ups. A total of 83 smokers (9.3%) withdrew from treatment and 116 (12.8%) stopped temporarily because of adverse effects. No differences were found in the percentages of discontinuation among the different treatment options. Adverse effects rarely were severe (n=10). Nevertheless, 41 subjects (4.5%) discontinued drug therapy indefinitely and 55 (6.1%) discontinued it temporarily because of mild adverse effects. Pharmacological therapies for smoking cessation are safe as long as they are appropriately prescribed and supervised by clinicians according to clinical practice guidelines. Adverse effects are primarily mild. Nonetheless, mild adverse effects may be perceived by patients as a serious enough problem to cause them to discontinue treatment.     

Effect of chitosan coating in preventing deterioration and preserving the quality of fresh‐cut papaya ‘Maradol’

BACKGROUND: Chitosan can form antimicrobial, semi‐permeable barriers that limit gas exchange and reduces water loss in fruits. Consumer interest in fresh‐cut papaya fruit is leading to increasing demand because of its sensorial and antioxidant properties. However, papaya is a highly perishable product that is prone to loss of weight, loss of firmness and microbial attack. The aim of this study was to evaluate the effect of chitosan coatings on the overall quality of fresh‐cut papaya. Chitosan coatings of low (LMWC), medium (MMWC) and high (HMWC) molecular weights, at concentrations of 0.01 and 0.02 g mL^?1, were applied to fresh‐cut papaya cubes. The treated cubes were stored at 5 °C and changes in quality were evaluated. RESULTS: MMWC maintained the highest color values (L* and b*) and firmness. Chitosan coatings suppressed mesophilic plate count, and the growth of molds and yeast, compared to controls. The MMWC coatings at 0.02 g mL^?1 resulted in the highest antimicrobial activity and decreased the activity of the enzymes polygalacturonase and pectin methylesterase, followed by low and high MW chitosan coatings at 0.02 g mL^?1. CONCLUSION: The application of the MMWC treatment at 0.02 g mL^?1 could be used to reduce deteriorative processes, maintain quality and increase the shelf life of fresh‐cut papaya stored at 5 °C. Copyright © 2008 Society of Chemical Industry     

Phenolic characterisation of red grapes autochthonous to Andalusia

Twenty six phenolic compounds in wine grapes were identified and quantified in five winegrape varieties using the complementary information from high-performance liquid chromatography coupled to diode array and fluorescence detectors, and mass spectrometry in both positive and negative mode. Fourteen different anthocyanins were identified in these grapes. In all varieties, malvidin-3-glucoside and its derivatives, mainly p-coumaroyl derivatives, were the major compounds. Seven flavonols were detected, most as quercetin and myricetin derivatives, and few qualitative differences were found among varieties. Total hydroxycinnamic content was rather low in all varieties. Lastly, catechin and epicatechin were detected in both skin and seed; differences in respect of the content in the seeds can be attributed to differences in the number and weight of seed per berry in each variety. The results of the characterisation can be used to select winemaking techniques aimed at improving the quality of the final wine.     

Effect of cofermentation of grape varieties on aroma profiles of la mancha red wines

The effect of winemaking using blends of red grape varieties cultivated in La Mancha region (Spain) on the aroma profile of wines was researched by chemical characterization. Free and glycosidically bound aroma compounds were isolated by solid phase extraction using dichloromethane and ethyl acetate, respectively, as solvents in elution and then analyzed by gas chromatography-mass spectrometry. Free and bound volatile compounds were analyzed in Cencibel, Bobal, and Moravia Agria monovarietal wines, and in 3 wines obtained with the blending of grapes: Cencibel (50%) + Bobal (50%); Cencibel (50%) + Moravía Agria (50%); Cencibel (33%) + Bobal (33%) + Moravía Agria (33%). Aroma compounds were studied in terms of odor activity values (OAVs). Ninety free aroma compounds and sixty-five bound aroma compounds were identified and quantified. The odor activity values for the different compounds were classified into 7 odorant series. The fruity and sweet series contributed most strongly to the aroma profile of all wines, independently of the winemaking technique used. In general, co-winemaking wines present a more complex chemical profile than monovarietal wines. Practical Application: Some grape varieties could benefit from this process with the presence of other varieties that might have an excess of aroma compounds. In this study, the wines were elaborated by blending different grape varieties together; this process implies co-maceration and co-fermentation steps. The co-winemaking technique could benefit from additional molecules provided by the other varieties, which results in a more complex formation than in the case of monovarietal wines. This technique provides a viable alternative to traditional winemaking methods for improving and enhancing the sensory profile of elaborated wines.