查看更多>>摘要：Panax ginseng C.A. Meyer (Korean ginseng) is one of the most valuable medicinal plants, recognised for its neuroprotection and other beneficial health effects. It is present in a wide range of food products, namely plant food supplements (PFS) and herbal infusions. However, other Panax species, having distinct therapeutic effects, are also known as ginseng, pointing out the need of authenticating such products. The present work aims at proposing a new high-resolution melting (HRM) method to differentiate five Panax species (P. ginseng, P. quinquefolius, P. notoginseng, P. japonicus and P. trifolius), targeting the gene encoding the dammarenediol synthase, involved in the biosynthesis pathway of ginsenosides. A Panax-specific real-time PCR assay was successfully developed with high analytical performance parameters (Efficiency = 100.5 %, R2 = 0.995, dynamic range 10 ng-1 pg of ginseng DNA). Panax DNA was detected in 17 out of 23 ginseng-containing commercial foods, including herbal infusions and PFS. For the first time, HRM analysis differentiated five Panax species with high level of confidence (>98 %), which corroborated sequencing data. Fourteen products were successfully clustered, being all except one in accordance with their labelling statements. Therefore, the present work proposes a reliable and high-throughput tool to authenticate ginseng products that could be useful for control laboratories.
查看更多>>摘要：Cassava is a source of starch but for certain applications the starch needs to be modified. Acid hydrolysis is a type of chemical modification that allows the starch to become suitable for confectionary applications. The objective of this study was to obtain acid-thinned cassava starch, describe its characteristics and investigate the pasting and technological properties in the presence of a mixture of sugars as used in the candy industry (sucrose and glucose syrup). Microscopic analysis did not visualize any alteration in granule form, but some adhered powders was observed on the surface of the granules on the scanning electron microscopy images. Granule size distribution altered from unimodal to bimodal, particle size determination and span detected starch granule agglomeration after acid hydrolysis. X-ray spectrum showed increase of crystallinity from 15.7 to 18.8%. In sugar solution, absorption, swelling power at 90 degrees C and gelatinization temperature increased, and the rapid viscosity analysis did not detect increase in viscosity in the hot solution, which is a desirable outcome for this type of modification. The acid hydrolysis did not alter granule morphology, the pasting and technological properties changed and provided desirable functional properties for application in confectionary products especially in gum candy.
查看更多>>摘要：Cheese presents remarkable diversity and organoleptic richness favored by microbial communities. Different yeasts have already been reported as contributors to cheese characteristics. In this study we aimed to characterize K. lactis B10 and T. delbrueckii B14 probiotic potential and to evaluate their impact on cheese. Yeasts were subjected to hemolysis, mucin degradation, co-aggregation with pathogens, in vivo survival, and antagonism to salmonellosis. Cheeses were produced with pasteurized milk coagulated using commercial rennet. Cheeses were evaluated for texture profile and sensory acceptance up to 40 days of maturation. Both yeasts presented higher co-aggregation to Salmonella than Saccharomyces boulardii. Although both yeasts satisfactorily survived the passage through the gastrointestinal tract, only K. lactis B10 resulted in high survival rate (90%) of mice against salmonellosis. Cheese produced with yeasts on the surface presented no eyes formation, while yeasts inoculated in the mass increased eyes formation. At 21 days of maturation yeasts inoculated in the mass resulted in lower hardness (1787.91), gumminess (1528.70) and chewiness (1339.63). Taste and purchase intention were higher for the cheese produced with yeasts inoculated in the mass. For all maturation times evaluated, most of the tasters expressed a preference for the cheese produced with yeasts inoculation in the mass.
Manjarres, Juan J.Ramirez, CristinaBolivar, GermanAlvarez, Alejandro...
10页
查看更多>>摘要：One of the main causes of cherry tomato postharvest loss is diseases caused by food-contaminating fungi. Edible coatings (ECs) can preserve the quality of this crop and can serve as carriers of lactic acid bacteria (LAB), which have demonstrated inhibitory potential against phytopathogenic fungi. In the present study, the effectiveness of the LAB strain Lactiplantibacillus plantarum A6 incorporated into an EC based on exopolysaccharide from Weissella confusa JCA4 on the physicochemical and microbiological quality of cherry tomato was evaluated. The fruit were artificially inoculated with the fungi Aspergillus niger, Fusarium sp., and Rhizopus stolonifer to test the antifungal potential of the coating. The physicochemical and microbiological quality of cherry tomato was studied at two storage temperatures to calculate its shelf life. L. plantarum A6 remained viable both in the solution and on the surface of the fruit after coating, protecting the fruit against two of the three evaluated fungi (Fusarium sp. and Rhizopus stolonifer). The EC controlled weight loss, maintained firmness, and slowed the respiration rate of cherry tomato; the other physicochemical properties and the appearance of the fruit were not negatively affected. Based on these results, prolongation of shelf life was achieved by the application of the exopolysaccharide coating.
查看更多>>摘要：Wheat bran has a short shelf life, which could be prolonged by reducing the activity of enzymes in lipid degradation. In this study, high-intensity ultrasound treatment (400 W, 80% amplitude, 15 min), with or without cooling, was investigated for reducing the activity of lipase and peroxidase of wheat bran. Lipid stability pa-rameters (free fatty acid content, peroxide value, anisidine value) of bran with coarse and reduced particle size (median 50th percentile diameter 503 and 177 mu m, respectively) were followed under ambient or refrigerated storage conditions. Ultrasonic treatment without accompanying cooling inactivated 63% of lipase and 90% of peroxidase, but also decreased the antioxidant activity of bran by 13%. Compared with the untreated bran, the ultrasound-treated bran was darker, redder, and yellower. When ambiently stored, the critical anisidine value (10) of the unprocessed bran was exceeded after only 2 months, whereas the ultrasound-treated bran had an acceptable anisidine value for almost 12 months. Cooling during ultrasonication limits the ability to inactivate enzymes, and the reduction in bran particle size promotes its oxidative deterioration. The application of high-intensity ultrasound without cooling is beneficial for prolonging the oxidative stability of wheat bran compared to refrigerated storage.
查看更多>>摘要：White truffles are highly valuable, but the aroma is susceptible to change with storage. How volatile composition and micmbiome of Tuber magnatum evolve by storage time is poorly understood. Changes in bacterial community and volatile compounds of T. magnatum fruiting bodies with storage time at 23 degrees C were investigated. Truffles (21 fruiting bodies) were collected from different sites in Italy, Hungary, and Croatia. Single fruiting bodies were subsampled at four time points (day (D)0, 3, 6, and 9). Gas chromatography-mass spectrometry and microbiome composition using PCR-high throughput sequencing were used to analyse the volatiles and bacterial communities, respectively. Spoilage compounds atypical of truffles increased with storage time. Likewise, bacterial communities changed with storage time; families belonging to Xanthobacteraceae dominated at DO and gradually evolved to more Rhizobiaceae and Pseudomonadaceae by D3 and D6, and finally with more prominent Xanthomonadaceae and Burkholderiaceae at D9. Overall, storage time had increased the diversity of bacterial communities. The micmbiome and volatile data were correlated using regularised canonical correlation analysis and determined correlations between 2-methylisoborneol and five bacterial OTUs. Potential candidate bacteria and their volatile metabolites can serve as markers for truffle spoilage. The results highlighted the mechanisms by which the degradation of expensive truffles occur.
查看更多>>摘要：In this study, the determination of Xinjunan pesticide residue in apple, cottonseed, pepper, tomato, grape and pear by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was established. The samples were purified by a modified QuEChERS method. The analysis was performed by UPLC-MS/MS in multiple reaction monitoring (MRM) mode. Acetonitrile and 1.0 mmol L-1 ammonium acetate (containing 0.1% formic acid) were used as the mobile phases. The external standard method was used for quantification. The average recoveries were 75.6-106.2% with an RSD <= 8.8%. The limits of quantification (LOQs) were 2.0 mu g/kg for apple, pepper, tomato, grape and pear and 10.0 mu g/kg for cottonseed. The proposed method is fast, sensitive, simple, and accurate and could be used for the quantification of Xinjunan pesticide residue in foodstuffs of plant origin.
Bhattacharya, AbhishekWiemann, MathiasStalbrand, Henrik
11页
查看更多>>摘要：Galactomannan (GM) in legumes and acetyl-galactoglucomannan (AcGGM) in softwoods are wide-spread 13-mannans. Their depolymerisation is catalyzed by 13-mannanases. We have investigated a cell-surface exposed and galactose-tolerant 13-mannanase (BoMan26B) from the abundant gut bacterium Bacteroides ovatus. Glycosidases from the gut microbiota have potential for production of prebiotics, such as dietary saccharides that would promote beneficial bacteria in the gut. BoMan26B was explored for production of potential prebiotics. Using the above 13-mannans as substrate we investigated the product profiles using a herein developed new high-resolution anion-exchange chromatography procedure. The produced linear and galactosyl-decorated 13-mannan-oligosaccharides (MOS/GMOS) were mainly of degree of polymerization (DP) 2-6, consistent with the glycan-binding subsites of BoMan26B. Some GM and AcGGM products were acetylated. DP 2-6 MOS were produced at a yield of 30 and 33% (w/w) from GM and AcGGM, respectively. In addition, about as much DP 2-6 GMOS were produced, assessed using guar a-galactosidase as analytical aid. Growth studies using the human gut bacteria Bifidobacterium adolescentis ATCC 15703 (acetate producer) and Roseburia hominis DSMZ 6839 (butyrate producer) revealed significant differences in utilization of specific MOS/GMOS. The prebiotic potential of the MOS/ GMOS generated by BoMan26B was further underlined by the observation that both bacterial strains produced short-chain fatty acids.
查看更多>>摘要：A novel active packaging gelatin film incorporated with protocatechuic acid (PCA) was prepared and characterized. After addition of PCA from 0.1 to 1.0%, gelatin films showed the improved extensibility and barrier properties with better elongation at break, lower water vapor permeability and UV light transmission compared with control group. Meanwhile, the higher thickness and total color difference, weaker tensile strength of these films were also found in gelatin-PCA composite films. The molecular interaction of these films between PCA and gelatin were non-covalent linkages, including hydrogen bond, hydrophobic interaction and electrostatic interaction, contributing to homogenous and smooth microstructures observed in SEM morphologies of gelatin films containing PCA of 0.1-1.0%. In addition, gelatin-PCA composite films presented the obvious antioxidant capability to scavenge DPPH radicals and the significant inhibitory effect on total viable counts of beef in chilled storage condition. Furthermore, they also exhibited strong antibacterial effects against E. coli O157:H7 and S. aureus both in vitro as well as the challenge of beef preservation in 4 degrees C simulation tests. These results suggested that fish gelatin-PCA composite film, as a novel active packaging film with good functional property and high biological activity, has promising application on foods preservation.
NSTL
Elsevier