Biofortification with selenium as an alternative to increase the total phenolic compounds in brassicas: a systematic review and meta-analysis

The ability of brassicas to accumulate selenium is crucial for their positive effects on health. Selenium improves the immune system and the antioxidant defenses. Selenium biofortification of brassicas has therefore been explored to increase dietary selenium intake in humans. However, the effects of selenium biofortification on bioactive compounds, mainly phenolic compounds, are not clear. So, this systematic review and meta-analysis aimed to answer the question ‘What are effects of the biofortification of brassicas with selenium on total phenolic compounds?’ Ten studies, which assessed the effect of selenium biofortification on total phenolic compounds, were selected for qualitative synthesis and four studies were included in the meta-analysis after a thorough literature review of the PubMed, Science Direct, and Web of Knowledge databases. The quality of the evidence ranged from high to moderate. The meta-analysis results indicated that the total phenolic compound content was significantly higher (P = 0.002) in the supplemented group but the results showed considerable heterogeneity (P < 0.00001, I² = 97%) between studies. This systematic review and meta-analysis summarizes the effect of Se biofortification on the increase in the content of total phenolic compounds and it suggests that several factors can affect this relationship. © 2023 Society of Chemical Industry.     

Novel implementation of laser ablation tomography as an alternative technique to assess grain quality and internal insect development in stored products

In the last century, there have been important advances in peering inside the internal grain environment. This has included electrical conductance mills, acoustical tools, near-infrared spectroscopy, and soft X-ray imaging. Each technique has their own advantages and limitations. In this current study, we describe a novel process for assessing grain quality and internal insect development in grain using laser ablation tomography (LATscan) and compare it to soft X-ray imaging for three life stages (larva, pupa, adult) of Sitophilus zeamais and Rhyzopertha dominica. Our results suggest that X-rays overestimated grain volume loss by about a quarter compared to LATscan. Moreover, LATscan produces a rich digital dataset on the level of microns that can be explored to ask biologically-relevant questions. We discuss the current limitations of LATscan in context with other techniques. Ultimately, the results highlight LATscan as a useful additional tool to further our understanding pest-commodity interactions in the postharvest supply chain.     

南美白对虾产业发展报告

为研究乳酸链球菌素（Nisin）对高水分烤虾常温下贮藏性的影响,在烤虾样品中分别添加20、60和100 mg/kg的Nisin,以感官结合菌落总数、蜡样芽孢杆菌数、挥发性盐基氮、pH等指标对样品品质进行评价。结果表明,烤虾的感官评分在常温贮藏过程中逐渐下降,菌落总数、蜡样芽孢杆菌数、挥发性盐基氮与pH则呈增长趋势。随着Nisin添加量的增加,菌落总数、蜡样芽孢杆菌数、挥发性盐基氮的增长趋慢。第6 d时,未加Nisin的对照组样品菌落总数达到行业标准《调味烤虾》中规定的限值（3×10⁴ CFU/g）,而添加20、60、100 mg/kg Nisin的样品,菌落总数达到规定限值的时间分别被延长至8、12和14 d。本研究表明Nisin对高水分烤虾中蜡样芽孢杆菌等腐败微生物生长有明显的抑制作用,能有效延长产品的货架期。     

Inactivation of different strains of Escherichia coli O157:H7 in various apple ciders treated with dimethyl dicarbonate (DMDC) and sulfur dioxide (SO2) as an alternative method

Escherichia coli has been identified as the causative agent in numerous foodborne illness outbreaks associated with the consumption of fresh apple cider. Apple cider has a pH which is normally below 4.0 and would not be considered a medium capable of supporting the growth of foodborne pathogens. The association of unpasteurized apple cider with foodborne illness due to E. coli O157:H7 has however, led to increased interest in potential alternative methods to produce pathogen free cider. Apple cider was prepared from eight different apple cultivars, inoculated with approximately 10⁶–10⁷ CFU of three strains of E. coli O157:H7 per ml (933, ATCC 43889, and ATCC 43895) and tested to determine the effectiveness of sulfur dioxide (SO₂) and dimethyl dicarbonate (DMDC). Bacterial populations for treated and untreated samples were then enumerated by using non-selective media. Eight different ciders were treated with DMDC (125 and 250 ppm) and SO₂ (25, 50, 75, 100 ppm). Greater than a 5-log reduction was achieved at room temperature with 250 ppm of DMDC and 50 ppm of SO₂ after the incubation time of 6 h and 24 h, respectively. Addition of DMDC and/or SO₂ may offer an inexpensive alternative to thermal pasteurization for the production of safe apple cider for small apple cider producers.     

A note on the incidences of Salmonella spp., Listeria spp. and Escherichia coli O157:H7 serotypes in Turkish sausage (Soudjouck)

The incidence of Salmonella spp., Listeria monocytogenes and Escherichia coli O157:H7 was determined in 100 Turkish sausage (soudjouck) samples collected from shops and markets in the Afyon province, Turkey. Salmonella spp. were detected in 7% of the samples. All of the isolates were S. enterica Paratyphi B. In addition, Listeria spp. were detected in 9% of the samples. Its distribution was 7% L. monocytogenes and 1% each of L. ivanovii and L. innocua. Serological study of the seven L. monocytogenes isolates showed that three of these were 1/2 ab, three were 5/6 ab and one was 1 ab. E. coli O157:H7 was not detected in any of the samples. The pH values of the samples ranged from 4.8 to 6.5. In conclusion, increasing number of listeriosis and salmonellosis cases in Turkey and the contamination levels found indicate that risk assessment and improved preventive measures are required for these sausages.     

Effect of Natural Antibrowning Agents on Color and Related Enzymes in Fresh-Cut Fuji Apples as an Alternative to the Use of Ascorbic Acid

ABSTRACT:  Polyphenoloxidase (PPO) and peroxidase (POD) were evaluated in fresh-cut Fuji apple slices and the effect of the individual or combined use of ascorbic acid, 4-hexylresorcinol, N-acetylcysteine, and glutathione on their respective activities was determined. Additionally, color changes during storage at 4 °C were measured throughout 14 d of storage. PPO activity increased with storage time and was inhibited by the individual use of N-acetylcysteine and glutathione. POD activity in the apple slices was effectively inhibited by the combined use of ascorbic acid with any of the other antibrowning agents. On the other hand, an individual treatment with 1% N-acetylcysteine helped in maintaining the color of fresh-cut apples during 14 d of storage, whereas the use of ascorbic acid was not enough to prevent color deterioration of the apple slices from the 1st day of storage. The results obtained corroborated the effectiveness of other natural antibrowning agents over the traditional use of ascorbic acid in the control of the enzymatic browning in the fresh-cut fruit industry.     

Determination of total phenols in tea infusions,tomato and apple juice by terbium sensitized fluorescence method as an alternative approach to the Folin–Ciocalteu spectrophotometric method

A fast screening of total phenols in tea infusions, tomato and apple juice samples using terbium sensitized fluorescence is described. The proposed method is based on the fluorescence sensitization of terbium (Tb³⁺) by complexation with flavonols (quercein as a reference standard) (at pH 7.0), which fluoresces intensely with an emission maximum at 545 nm when excited at 310 nm. Quercetin and terbium cations (at pH 7.0) form a stable complex and the resulted emission at 545 nm can be used for the determination of the total phenols concentration expressed in terms of “quercetin equivalent”. Based on the obtained results, a sensitive, simple and rapid spectrofluorimetric method was developed for the determination of total phenols. In the optimum conditions, the calibration graph was linear from 0.01 to 2 μg mL⁻¹, with the limit of detection of 0.002 μg mL⁻¹. The relative standard deviation values were in the range of 0.75–2.3%. The total concentrations of quercetin equivalent in five tested samples were found in the range of 6.6–27.9 μg mL⁻¹ and the results compare favorably with those obtained by spectrophotometric method (r = 0.999).     

Use of a YAP1 overexpression cassette conferring specific resistance to cerulenin and cycloheximide as an efficient selectable marker in the yeast Saccharomyces cerevisiae.

Drug-resistance markers for yeast transformation are useful because they can be applied to strains without auxotrophic mutations. However, they are susceptible to technical difficulties, namely lower transformation efficiency and the appearance of drug-resistant mutants without the marker. To avoid these problems, we have constructed a phosphoglycerate kinase (PGK) promoter-driven YAP1 expression cassette, called PGKp-YAP1. Yeast cells containing PGKp-YAP1 were resistant to cycloheximide, a protein synthesis inhibitor, and also to cerulenin, a fatty acid synthesis inhibitor, but not to other drugs tested. The transformation efficiency of PGKp-YAP1 using cerulenin selection was comparable to that using a URA3 auxotrophic marker when low concentrations of cerulenin were used. Non-transformed drug-resistant colonies did appear on the low-concentration cerulenin plates. However, these non-transformed colonies could easily be identified, based on their cycloheximide sensitivity and/or their resistance to aureobasidin A to which the transformants were sensitive. Therefore, the dual drug resistance of PGKp-YAP1 could be used as an effective selection for PGKp-YAP1 recipient cells. The PGKp-YAP1 marker was used to disrupt the LYS2 gene and to transform an industrial yeast strain, indicating that this marker can be used for efficient and reliable gene manipulations in any Saccharomyces cerevisiae strain.