Assessment of pesticide use and pesticide residues in vegetables from two provinces in Central Vietnam.

Pesticide residue in food, especially in vegetables, is one of the important parameters to assess food safety. This study evaluates the pesticide use in vegetables from two provinces in Central Vietnamand and present data on pesticides detected in vegetables sampled from the sites. The potential health risk associated with the contamination of four commonly used pesticides in different vegetables is also discussed. Both household surveys and monitoring campaigns were conducted. The survey showed that improper pesticide application, storage, and waste disposal prevailed at the study sites. Only 20% of the respondent were aware of pesticide toxicity. As a result, pesticides were detected in 81% out of 290 vegetable samples collected at harvesting time. Up to 23% of samples had pesticide residues above the Maximum Residue Limit values. The highest total pesticide concentration quantified in vegetables in Thua Thien Hue was 11.9 mg/kg (green onions), and in Quang Binh was 38.6 mg/kg (mustard greens). Median residue levels of individual pesticides in vegetables ranged from 0.007 to 0.037 mg/kg. Among the ten target pesticides, cypermethrin, difenoconazole, and fenobucarb were detected at the highest frequencies (72%, 41%, and 37%, respectively). Pesticide residues varied between seasons at both study provinces. Pesticide contamination in the wet season was significantly higher than in the dry season. This study also discovered a potential health risk associated with fipronil residues in vegetables in Thua Thien Hue province. The paper provides recommendations for mitigation measures (both technological and social) in reducing potential health risks linked to pesticide use in vegetables in the region.

Rich d-Fructose-Containing Polysaccharide Isolated from Myxopyrum smilacifolium Roots toward a Superior Antioxidant Biomaterial.

The presented study attempts to unveil and evaluate the antioxidant activity of a novel heteropolysaccharide separated from the roots of Myxopyrum smilacifolium (denoted as PS-MSR). The molecular weight of PS-MSR is found to be 1.88 × 104 Da and contains two principal sugars, which are d-glucose and d-fructose, in the backbone. Decoding the structure of the obtained PS-MSR sample has disclosed a novel polysaccharide for the first time. Indeed, the PS-MSR is composed of (1 → 3)-linked glucosyl units and (2 → 3)-linked fructosyl units. In addition, the 1D and 2D NMR spectra of the PS-MSR sample display the repeating unit of the isolated polysaccharide, [→3)-α-d-Glcp-(1 → 3)-ß-d-Frucf-(2 → 3)-ß-d-Frucf-2 → 3)-)-ß-d-Frucf-ß-(2→] n . Interestingly, the PS-MSR sample exhibits outstanding antioxidant activity, signifying the potential utilization of the explored polysaccharide for antioxidant-based material.

Novel Exopolysaccharide Produced from Fermented Bamboo Shoot-Isolated Lactobacillus Fermentum.

This study aimed at providing a route towards the production of a novel exopolysaccharide (EPS) from fermented bamboo shoot-isolated Lactobacillus fermentum. A lactic acid bacteria strain, with high EPS production ability, was isolated from fermented bamboo shoots. This strain, R-49757, was identified in the BCCM/LMG Bacteria Collection, Ghent University, Belgium by the phenylalanyl-tRNA synthetase gene sequencing method, and it was named Lb. fermentum MC3. The molecular mass of the EPS measured via gel permeation chromatography was found to be 9.85 × 104 Da. Moreover, the monosaccharide composition in the EPS was analyzed by gas chromatography-mass spectrometry. Consequently, the EPS was discovered to be a heteropolysaccharide with the appearance of two main sugars-D-glucose and D-mannose-in the backbone. The results of one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance spectroscopy analyses prove the repeating unit of this polysaccharide to be [→6)-ß-D-Glcp-(1→3)-ß-D-Manp-(1→6)-ß-D-Glcp-(1→]n, which appears to be a new EPS. The obtained results open up an avenue for the production of novel EPSs for biomedical applications.

Decoding the Capability of Lactobacillus plantarum W1 Isolated from Soybean Whey in Producing an Exopolysaccharide.

This study aims at producing exopolysaccharides (EPS) from a lactic acid bacterial strain. The soybean whey-isolated Lactobacillus plantarum W1 (EPS-W1), which belongs to genus Lactobacillus, is identified using the phenylalanyl-tRNA sequencing method. Of all the examined strains, R-49778 (as numbered by BCCM/LMG Bacteria Collection, Ghent University, Belgium) showed the highest capability of producing exopolysaccharides. Structural characterization revealed a novel exopolysaccharide consisting of repeating units of →6)-d-Glcp-(1→; →3)-d-Manp-(1→; →3)-d-Glcp-(1→ and a branch of →6)-d-Manp-(1→; →2)-d-Glcp-(1→. This discovery opens up avenues for the production of EPS for food industries, functional foods, and biomedical applications.

Towards improved quality benchmarking and shelf life evaluation of black tiger shrimp (Penaeus monodon).

An improved quality benchmarking and shelf life evaluation of freshly harvested black tiger shrimp (Penaeus monodon) was pursued by combining sensory and chemical methods. This involved developing a quality index method (QIM) to further assess both freshness and shelf life of the studied shrimp samples. The quality index included the use of trimethylamine (TMA-N), total volatile basis nitrogen (TVB-N), histamine, and hypoxanthine, which were performed at scheduled times during the ten days of ice storage (0°C). Shelf life of the studied shrimp was most likely to be 8days, and there were positive linear correlations between quality indices (QI) and storage period. The quality of shrimp decreased over storage time. In fact, significant changes of chemical and sensory characteristics of the shrimp samples would become more obvious from day 5 onwards. Besides, quality classification of black tiger shrimp involved four main levels, namely: excellent, good, moderately acceptable, and just acceptable.