Food safety evaluation of broccoli and radish sprouts

Utilization of Germinated Seeds as Functional Food Ingredients: Optimization of Nutrient Composition and Antioxidant Activity Evolution Based on the Germination Characteristics of Chinese Chestnut (Castanea mollissima)

The current study investigated the impact of germination duration on the functional components (vitamin C, γ-aminobutyric acid (GABA), polyphenols, flavonoids) and antioxidant activity of germs and cotyledons of the germinated Chinese chestnut (Castanea mollissima). We utilized seeds of the "Zaofeng" Chinese chestnut to germinate, and sowed the seeds in wet sand at 22 °C and 85% relative humidity. The germination rate, length, diameter, and fresh weight of the sprouts were investigated at 0, 2, 4, 6, 8, and 10 days after sowing, and the kinetic changes of amylose, amylopectin, sugar components, soluble protein, vitamin C, GABA, total phenols, flavonoids, and the DPPH and ABTS free radical scavenging activity in the germs and cotyledons were monitored, respectively. The findings revealed that the germination rate and germ biomass increased continuously during germination. The germination rate reached 90% on the 8th day after sowing. Germination reduced amylose in cotyledons from 42.3% to 34.2%, amylopectin from 42.9% to 25.8%, total sugar from 12.6% to 11.4%, and vitamin C from 1.45 mg/g to 0.77 mg/g. Meanwhile, soluble protein in the embryos rose from 0.31% to 0.60%, vitamin C from 21.1 to 29.4 mg/g, GABA from 0.49 to 1.68 mg/g, total flavonoids from 53.6 to 129.7 mg/g, and ABTS antioxidant activity from 1.52 to 3.27 μmol TE/g. The average contents of D-fructose, inositol, vitamin C, GABA, polyphenols, and flavonoids and the DPPH and ABTS antioxidant activity in germs were as high as 22.5, 6, 35, 7.5, 10, 20, and 10 and 20-fold those of cotyledons, respectively. Especially, the average content of glucose in germ was as high as 80-fold that of cotyledon. D-xylulose, D-galacturonic acid, and D-ribose were only found in germs, but not in cotyledons. Considering the germ biomass and functional components content, germs of Chinese chestnuts germinated at 22 °C for 8 days are considered the most suitable raw material for functional food products. In conclusion, controlled germination not only enhances the physicochemical and functional properties of Chinese chestnut germs but also reduces the caloric content and improves the nutritional composition of the cotyledons appropriately. Moreover, the comprehensive evaluation of compositional changes and functionality in the embryo and cotyledon of Chinese chestnuts will provide a solid foundation for subsequent functional food processing utilizing germinated Chinese chestnuts.

Recent developments in applications of physical fields for microbial decontamination and enhancing nutritional properties of germinated edible seeds and sprouts: a review

Germinated edible seeds and sprouts have attracted consumers because of their nutritional values and health benefits. To ensure the microbial safety of the seed and sprout, emerging processing methods involving physical fields (PFs), having the characteristics of high efficiency and environmental safety, are increasingly proposed as effective decontamination processing technologies. This review summarizes recent progress on the application of PFs to germinating edible seeds, including their impact on microbial decontamination and nutritional quality and the associated influencing mechanisms in germination. The effectiveness, application scope, and limitation of the various physical techniques, including ultrasound, microwave, radio frequency, infrared heating, irradiation, pulsed light, plasma, and high-pressure processing, are symmetrically reviewed. Good application potential for improving seed germination and sprout growth is also described for promoting the accumulation of bioactive compounds in sprouts, and subsequently enhancing the antioxidant capacity under favorable PFs processing conditions. Moreover, the challenges and future directions of PFs in the application to germinated edible seeds are finally proposed. This review also attempts to provide an in-depth understanding of the effects of PFs on microbial safety and changes in nutritional properties of germinating edible seeds and a theoretical reference for the future development of PFs in processing safe sprouted seeds.

Radish microgreens produced without substrate in a vertical multi-layered growing unit are rich in nutritional metabolites

Growing microgreens on trays without substrate in a vertical multilayered growing unit offers several advantages over traditional agriculture methods. This study investigated the yield performance and nutritional quality of five selections of radish microgreens grown in sprouting trays, without a substrate using only water, in an indoor multilayer cultivation system using artificial light. Various parameters were measured, including fresh weight, dry matter, chlorophyll, minerals, amino acids, phenolics, flavonoids, anthocyanins, vitamin C, glucosinolates, and antioxidant activity with four different in vitro assays. After ten days, the biomass had increased by 6-10 times, and the dry matter varied from 4.75-7.65%. The highest yield was obtained from 'Asia red', while the lowest was from 'Koregon red'. However, 'Koregon red' and 'Asia red' had the highest dry matter. 'Asia red' was found to have the highest levels of both Chls and vitamin C compared to the other cultivars, while 'Koregon red' exhibited the highest levels of total phenolics and flavonoids. Although variations in the levels of individual glucosinolates were observed, there were no significant differences in the total content of glucosinolates among the five cultivars. 'Asia purple' had the highest anthocyanin content, while 'Asia green 2' had the lowest. The K, Mg, and Na concentrations were significantly highest in 'Asia green 2', and the highest Ca was recorded in 'Asia purple'. Overall, 'Asia purple' and 'Koregon red' were the best cultivars in terms of nutritional quality among the tested radish microgreens. These cultivars exhibited high levels of dry weight, total phenolics, flavonoids, anthocyanins, essential and total amino acids, and antioxidant activities. Moreover, the implementation of this vertical cultivation method for microgreens, which relies solely on water and seeds known for their tall shoots during the sprouting could hold promise as a sustainable approach. This method can effectively be utilized for cultivar screening and fulfilling the nutritional and functional needs of the population while minimizing the environmental impacts associated with traditional agriculture practices.

Metabolic Profiling of Primary and Secondary Metabolites in Kohlrabi (Brassica oleracea var. gongylodes) Sprouts Exposed to Different Light-Emitting Diodes

Light-emitting diode (LED) technology is one of the most important light sources in the plant industry for enhancing growth and specific metabolites in plants. In this study, we analyzed the growth, primary and secondary metabolites of 10 days old kohlrabi (Brassica oleracea var. gongylodes) sprouts exposed to different LED light conditions. The results showed that the highest fresh weight was achieved under red LED light, whereas the highest shoot and root lengths were recorded below the blue LED light. Furthermore, high-performance liquid chromatography (HPLC) analysis revealed the presence of 13 phenylpropanoid compounds, 8 glucosinolates (GSLs), and 5 different carotenoids. The phenylpropanoid and GSL contents were highest under blue LED light. In contrast, the carotenoid content was found to be maximum beneath white LED light. Principal component analysis (PCA) and partial least-squares discriminant analysis (PLS-DA) of the 71 identified metabolites using HPLC and gas chromatography-time-of-flight mass spectrometry (GC-TOF-MS) showed a clear separation, indicating that different LEDs exhibited variation in the accumulation of primary and secondary metabolites. A heat map and hierarchical clustering analysis revealed that blue LED light accumulated the highest amount of primary and secondary metabolites. Overall, our results demonstrate that exposure of kohlrabi sprouts to blue LED light is the most suitable condition for the highest growth and is effective in increasing the phenylpropanoid and GSL content, whereas white light might be used to enhance carotenoid compounds in kohlrabi sprouts.

Transduction of stx2a mediated by phage (Φ11-3088) from Escherichia coli O104:H4 in vitro and in situ during sprouting of mung beans

Escherichia coli O104:H4 strain 11-3088 encoding Stx2a is epidemiologically related to the foodborne outbreak associated with sprouts in Germany, 2011. Sprouting provides suitable conditions for bacterial growth and may lead to transduction of non-pathogenic strains of E. coli with Stx phages. Although transduction of E. coli by Stx phages in food has been documented, data on the phages from E. coli O104:H4 is limited. This study determined the host range of the bacteriophage Φ11-3088 from E. coli O104:H4 using E. coli O104:H4 ∆stx2::gfp::amp^r and demonstrated phage transduction during sprouting. The Φ11-3088∆stx transduced 5/45 strains, including generic E. coli, pap-positive E. coli O103:H2, ETEC, and S. sonnei. The expression level of Φ11-3088∆stx differed among lysogens upon induction. Of the 3 highly induced lysogens, the lytic cycle was induced in E. coli O104:H4∆stx2::gfp::amp^r and O103:H2 but not in S. sonnei. E. coli DH5α was the only strain susceptible to lytic infection by Φ11-3088∆stx. To explore the effect of drying and rehydration during seed storage and sprouting on phage induction and transduction, mung beans inoculated with the phage donor E. coli O104:H4∆stx2::gfp::amp^r (8 log CFU/g) were dried, rehydrated, and incubated with the phage recipient E. coli DH5α (7 log CFU/g) for 96 h. Sprouted seeds harbored about 3 log CFU/g of putative lysogens that acquired ampicillin resistance. At the end of sprouting, 71 % of putative lysogens encoded gfp, confirming phage transduction. Overall, stx transfer by phages may increase the cell counts of STEC during sprouting by converting generic E. coli to STEC.

Detection and Degradation Characterization of 16 Quinolones in Soybean Sprouts by Ultra-High Performance Liquid Chromatography-Tandem Mass Spectrometry

Recently, there have been increasing safety concerns about the illegal abuse of quinolone in soybean sprouts. This study aimed to establish an ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the simultaneous detection of 16 quinolones (QNs) in soybean sprouts, and then reveal their degradation characteristics. The samples were extracted with acetonitrile (with 1% formic acid), purified by a C18 adsorbent, and separated by an ACQUITY UPLC BEH C18 (1.7 μm, 2.1 mm × 100 mm) column. The internal standard method was applied for quantitative determination. The results demonstrated that the quantification linear range for 16 QNs was between 2.0 ng/mL and 50.0 ng/mL. The detection limits were between 0.5 μg/kg and 4.0 μg/kg, and the quantification limits were between 2.0 μg/kg and 20.0 μg/kg. This method was used to screen for quinolones in 50 batches of market soybean sprouts; the obtained results showed good agreement with those of the standard method. It was found that QNs possessed longer degradation half-life (T_1/2) in the storage stage of soybean sprouts, while they degraded to some extent during the germination stage via active enzyme action. In particular, ciprofloxacin was the most stable QNs with a T_1/2 of 70.71 d during the storage stage of soybean sprouts. This work not only offers an accurate and efficient QNs residual analysis strategy but also provides a reference for the supervision and management of QNs in foods.

Sprouts Use as Functional Foods. Optimization of Germination of Wheat (Triticum aestivum L.), Alfalfa (Medicago sativa L.), and Radish (Raphanus sativus L.) Seeds Based on Their Nutritional Content Evolution

Wheat, alfalfa, and radish sprouts are well-renowned for their high nutritional content. However, their optimal imbibition and germination durations are rarely considered in the literature. In this study, reduced imbibition times of 3 h, 10 h, and 4 h were demonstrated for the wheat, alfalfa, and radish seeds, respectively. The evolution of their crude fat, proteins, polyphenols, antioxidant activity, and vitamins were investigated over 7 days of germination. The crude fat and protein loads of these sprouts slightly varied during germination, whereas the phenolic compounds and antioxidant activity maxed out at day 7, 5, and 6 for the wheat, alfalfa, and radish sprouts, respectively, with significant levels of catechin. The vitamins highly increased, showing noteworthy yet different peaks of growth depending on the seed and the vitamin analyzed. Interestingly, alfalfa and radish sprouts, taken at their optimal germination day, would decidedly contribute to meet our Recommended Daily Allowances (RDAs) of vitamins E, A, and B6. Overall, for a greater nutritional content and a potential use of these sprouts as nutraceutical ingredients, our results suggested to leave the wheat, alfalfa, and radish seeds to germinate only over 7, 4, and 6 days, respectively, after which their nutritional quality tended to decrease.

Accumulation of Agmatine, Spermidine, and Spermine in Sprouts and Microgreens of Alfalfa, Fenugreek, Lentil, and Daikon Radish

Sprouts and microgreens are a rich source of various bioactive compounds. Seeds of lentil, fenugreek, alfalfa, and daikon radish seeds were germinated and the contents of the polyamines agmatine (AGM), putrescine (PUT), cadaverine (CAD), spermidine (SPD), and spermine (SPM) in ungerminated seeds, sprouts, and microgreens were determined. In general, sprouting led to the accumulation of the total polyamine content. The highest levels of AGM (5392 mg/kg) were found in alfalfa microgreens, PUT (1079 mg/kg) and CAD (3563 mg/kg) in fenugreek sprouts, SPD (579 mg/kg) in lentil microgreens, and SPM (922 mg/kg) in fenugreek microgreens. A large increase in CAD content was observed in all three legume sprouts. Conversely, the nutritionally beneficial polyamines AGM, SPD, and SPM were accumulated in microgreens, while their contents of CAD were significantly lower. In contrast, daikon radish sprouts exhibited a nutritionally better profile of polyamines than the microgreens. Freezing and thawing of legume sprouts resulted in significant degradation of CAD, PUT, and AGM by endogenous diamine oxidases. The enzymatic potential of fenugreek sprouts can be used to degrade exogenous PUT, CAD, and tyramine at pH values above 5.

Food sources and biomolecular targets of tyramine

Tyramine is a biogenic trace amine that is generated via the decarboxylation of the amino acid tyrosine. At pico- to nanomolar concentrations, it can influence a multitude of physiological mechanisms, exhibiting neuromodulatory properties as well as cardiovascular and immunological effects. In humans, the diet is the primary source of physiologically relevant tyramine concentrations, which are influenced by a large number of intrinsic and extrinsic factors. Among these factors are the availability of tyrosine in food, the presence of tyramine-producing bacteria, the environmental pH, and the salt content of food. The process of fermentation provides a particularly good source of tyramine in human nutrition. Here, the potential impact of dietary tyramine on human health was assessed by compiling quantitative data on the tyramine content in a variety of foods and then conducting a brief review of the literature on the physiological, cellular, and systemic effects of tyramine. Together, the data sets presented here may allow both the assessment of tyramine concentrations in food and the extrapolation of these concentrations to gauge the physiological and systemic effects in the context of human nutrition.

Effect of slightly acidic electrolyzed water on natural Enterobacteriaceae reduction and seed germination in the production of alfalfa sprouts

Microbial contamination of sprouts commonly occurs because of the pathogens present on and in the seeds and the optimal conditions for bacteria growth provided during the germination and sprouting processes. This study examined the decontamination effect of slightly acidic electrolyzed water (SAEW), a 'generally recognized as safe' (GRAS) disinfectant, in the production process of alfalfa sprouts. SAEW with various available chlorine concentrations (ACC, 25, 35, 45 mg/L) and different pH levels (5.0, 5.7 and 6.4) was used to soak seeds for different length of time (0.5 and 6 h), after which the variations in natural Enterobacteriaceae, water absorption and seed germination (germination rate, weight and length of sprouts) were determined. The results showed that when the seeds were soaked with SAEW, albeit with different ACC (25, 35 and 45 mg/L) and pH levels (5.0, 5.7 and 6.4), a significant reduction of Enterobacteriaceae and no negative effect on sprout quality was observed. The water absorption and germination rates were also not significantly adversely affected by SAEW soaking. These findings suggest that SAEW could be used to decontaminate natural Enterobacteriaceae in the production of alfalfa sprouts, with no negative side effects on the alfalfa seeds.

The combined effects of ultrasound and lactic acid in inactivating microorganisms on fresh radish (Raphanus raphanistrum subsp. sativus): Microbiological and quality changes

In order to reduce the risk of microbial contamination in fresh radish (Raphanus raphanistrum) and ensure its safety, combined effects of ultrasound and lactic acid in inactivating microorganisms and quality changes of radish were studied. Fresh radish samples were inoculated with Listeria monocytogenes, Escherichia coli, Staphylococcus aureus, and Shigella sonnei separately and were treated with lactic acid (L) 1% and 2%, ultrasound (U) with the amplitude of 0%, 25%, 50%, and 75% for 15 and 30 min and their combination. The quality parameters, including total phenol content, firmness, and total color change, were evaluated on the day of the experiment and after 24 hr of cold storage. Results showed that both applied treatments and their combinations had significant (p < .05) inhibitory effect on all of the studied bacteria. Total phenolic content of the ultrasound treated samples led to higher amounts comparing to other samples. Results showed that using ultrasound power (75%), for 30 min significantly (p < .05) decreased the firmness of samples after 24 hr of cold storage. In conclusion, the application of ultrasound and lactic acid can extend the shelf life of fresh radish.

The primary active components, antioxidant properties, and differential metabolite profiles of radish sprouts (Raphanus sativus L.) upon domestic storage: analysis of nutritional quality

BACKGROUND

This study aimed to analyze the nutritional quality of radish sprouts (Raphanus sativus L.) after domestic short-term storage. We stored fresh radish sprouts at 25 ± 1 °C and at 4 ± 1 °C for 12 h, and detected phenolic substances, glucosinolates, isothiocyanates, vitamin C, and various antioxidant and abiotic stress-related factors. We investigated nutrient-related metabolic differences and associated pathways and postharvest treatment effects on nutritional quality using metabolomic analysis.

RESULTS

Most active substances and antioxidant properties, but not phenolic acids and vitamin C, decreased significantly (P < 0.05) upon domestic storage; this reduction decelerated at low temperatures. Short-term storage disrupted redox balance; low temperature enhanced stress resistance. Differences were observed in amino acid and vitamin derivatives, phospholipid accumulation, and organic acids. Short-term storage at ambient temperature promoted lysine, threonine, cysteine, vitamin H, phospholipid, and lauric (dodecanoic) acid accumulation, inhibiting proline, phosphatidic acid (PA) (14:1(9Z)/12:0), and phosphatidylcholine (PC) (O-18:0/O-18:0) accumulation; low-temperature, short-term storage promoted myristic acid and phospholipid accumulation and reduced methionine synthesis and vitamin H and K accumulation.

CONCLUSION

Overall, the nutritional quality of radish sprout decreased upon short-term storage, with differences in certain active substances. © 2018 Society of Chemical Industry.

Extraction, profiling and bioactivity analysis of volatile glucosinolates present in oil extract of Brassica juncea var. raya

Cruciferous vegetables are rich source of glucosinolates (GSLs), which in presence of myrosinase enzyme cause hydrolytic cleavage and result in different hydrolytic products like isothiocyanates, thiocyanates, nitriles and epinitriles. The GSLs hydrolytic products are volatile compounds, which are known to exhibit bioactivities like antioxidant, fungicidal, bioherbicidal and anticancer. Among the Brassicaceae family, Brassica juncea is very well known for high content of GSLs. In the present study, the isolation of volatile oil of B. juncea var. raya was done by hydrodistillation method using clevenger apparatus and further there extraction was done by solvents ethyl acetate and dichloromethane. The volatile compounds present in the extract were analysed by gas chromatography/gas chromatography-mass spectrometry (GC/GC-MS). Fatty acid esters, sulphur and/or nitrogen compounds, carbonyl compounds and some other volatile compounds were also identified. Besides the analytical studies, the extracts were analysed for their bioactivities including radical scavenging activity by using DNA nicking assay and cytotoxic effect using different human cancer cell lines viz. breast (MCF-7 and MDA-MB-231), prostate (PC-3), lung (A-549), cervix (HeLa) and colon (HCT116) by MTT assay. The oil extracts were efficiently able to reduce the increase of cancer cells in a dose-dependent manner. Among all cell lines, the most effective anticancer activity was observed in case of breast (MCF-7) cancer cell line. So, MCF-7 cells were used for further mechanistic studies for analysing the mechanism of anticancer activity. Confocal microscopy was done for analysing morphological changes in the cells and the images confirmed the features typical of apoptosis. For evaluating the mode of cell death, spectrofluorometric determination of reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) was done. The volatile oil extract treated MCF-7 cells had a significant increase in number of ROS, also there was a rise in percentage of cells with increased disruption of MMP. So, the present study marks necessary indication that B. juncea (raya) oil extracts significantly induces apoptosis in all the above mentioned cancer cells lines through a ROS-mediated mitochondrial pathway and thus play a remarkable role in death of cancer cells.

Plant-Microbe and Abiotic Factors Influencing Salmonella Survival and Growth on Alfalfa Sprouts and Swiss Chard Microgreens

Microgreens, like sprouts, are relatively fast-growing products and are generally consumed raw. Moreover, as observed for sprouts, microbial contamination from preharvest sources may also be present in the production of microgreens. In this study, two Salmonella enterica serovars (Hartford and Cubana), applied at multiple inoculation levels, were evaluated for survival and growth on alfalfa sprouts and Swiss chard microgreens by using the most-probable-number (MPN) method. Various abiotic factors were also examined for their effects on Salmonella survival and growth on sprouts and microgreens. Community-level physiological profiles (CLPPs) of sprout/microgreen rhizospheres with different levels of S. enterica inoculation at different growth stages were characterized by use of Biolog EcoPlates. In the seed contamination group, the ability of S. enterica to grow on sprouting alfalfa seeds was affected by both seed storage time and inoculation level but not by serovar. However, the growth of S. enterica on Swiss chard microgreens was affected by serovar and inoculation level. Seed storage time had little effect on the average level of Salmonella populations in microgreens. In the irrigation water contamination group, the growth of Salmonella on both alfalfa sprouts and microgreens was largely affected by inoculation level. Surprisingly, the growth medium was found to play an important role in Salmonella survival and growth on microgreens. CLPP analysis showed significant changes in the microbial community metabolic diversity during sprouting for alfalfa sprouts, but few temporal changes were seen with microgreens. The data suggest that the change in rhizosphere bacterial functional diversity was dependent on the host but independent of Salmonella contamination.IMPORTANCE Sprouts and microgreens are considered "functional foods," i.e., foods containing health-promoting or disease-preventing properties in addition to normal nutritional values. However, the microbial risk associated with microgreens has not been well studied. This study evaluated Salmonella survival and growth on microgreens compared to those on sprouts, as well as other abiotic factors that could affect Salmonella survival and growth on microgreens. This work provides baseline data for risk assessment of microbial contamination of sprouts and microgreens. Understanding the risks of Salmonella contamination and its effects on rhizosphere microbial communities enables a better understanding of host-pathogen dynamics in sprouts and microgreens. The data also contribute to innovative preventive control strategies for Salmonella contamination of sprouts and microgreens.

High-Pressure Processing of Broccoli Sprouts: Influence on Bioactivation of Glucosinolates to Isothiocyanates

Effects of high-pressure processing (HPP, 100-600 MPa for 3 min at 30 °C) on the glucosinolate content, conversion to isothiocyanates, and color changes during storage in fresh broccoli sprouts were investigated. A mild heat treatment (60 °C) and boiling (100 °C) were used as positive and negative controls, respectively. Glucosinolates were quantified using liquid chromatography-mass spectrometry, and isothiocyanates were quantified using high-performance liquid chromatography-photodiode array detection. A formation of isothiocyanates was observed in all high-pressure-treated sprouts. The highest degree of conversion (85%) was observed after the 600 MPa treatment. Increased isothiocyanate formation at 400-600 MPa suggests an inactivation of the epithiospecifier protein. During storage, color changed from green to brownish, reflected by increasing a* values and decreasing L* values. This effect was less pronounced for sprouts treated at 100 and 600 MPa, indicating an influence on the responsible enzymes. In summary, HPP had no negative effects on the glucosinolate-myrosinase system in broccoli sprouts.

High Occurrence Rate and Contamination Level of Bacillus cereus in Organic Vegetables on Sale in Retail Markets

Organic foods have risen in popularity recently. However, the increased risk of bacterial contamination of organic foods has not been fully evaluated. In this study, 100 samples each of organic and conventional fresh vegetables (55 lettuce samples and 45 sprout samples) sold in South Korea were analyzed for aerobic bacteria, coliforms, Escherichia coli, and Bacillus cereus. Although the aerobic bacteria and coliform counts were not significantly different between the two farming types (p > 0.05), the occurrence rate of B. cereus was higher in organically cultivated vegetables compared with those grown conventionally (70% vs. 30%, respectively). The mean contamination level of B. cereus-positive organic samples was also significantly higher (1.86 log colony-forming unit [CFU]/g vs. 0.69 log CFU/g, respectively) (p < 0.05). In addition, six samples of organic vegetables were found to be contaminated with B. cereus at over 4 log CFU/g categorized as unsatisfactory according to Health Protection Agency guideline. The relatively higher occurrence rate of B. cereus in organic vegetables emphasizes the importance of implementing control measures in organic vegetable production and postharvest processing to reduce the risk of food poisoning.

The Effect of Dry Yeast Fermentation on Chemical Composition and Protein Characteristics of Blue Lupin Seeds

The effect of 24-hour fermentation of lupin seeds by different yeast strains on their chemical composition was determined. After fermentation, the mass fraction of proteins increased and their in vitro digestibility and biological activity significantly improved. The amino acid profile of fermented products was similar to that of raw lupin seeds. The significant reduction in the mass fraction of oligosaccharides and phytate, but not of alkaloids was found. The pH level of fermented products decreased as a consequence of the increase of lactic and propionic acid mass fractions. The most favourable changes in the chemical composition of blue lupin seeds were obtained in fermentation with Saccharomyces cerevisiae baker's yeast and Fermivin 7013 strain.

Hydrogen peroxide, nitric oxide and UV RESISTANCE LOCUS8 interact to mediate UV-B-induced anthocyanin biosynthesis in radish sprouts

The cross talk among hydrogen peroxide (H₂O₂), nitric oxide (NO) and UV RESISTANCE LOCUS8 (UVR8) in UV-B-induced anthocyanin accumulation in the hypocotyls of radish sprouts was investigated. The results showed that UV-B irradiation significantly increased the anthocyanin accumulation and the expression of UVR8, and a similar trend appeared in radish sprouts subjected to cadmium, chilling and salt stresses regardless of light source. However, these responses disappeared under dark exposure. These results suggest that abiotic stress-induced anthocyanin accumulation and UVR8 expression were light-dependent. Moreover, abiotic stresses all enhanced the production of H₂O₂ and exogenous H₂O₂ addition significantly increased the anthocyanin concentration and UVR8 transcription, while these increases were severely inhibited by addition of dimethylthiourea (DMTU, a chemical trap for H₂O₂). It seems to suggest that H₂O₂ played an important role in the anthocyanin biosynthesis. Furthermore, addition of 0.5 mM sodium nitroprusside (SNP, a NO-releasing compound) substantially induced the anthocyanin accumulation, and H₂O₂-induced anthocyanin accumulation and UVR8 expression were significantly suppressed by co-treatment with 2-phenyl-4,4,5,5-tetramethylimidazoline-3-oxide-1-oxyl (PTIO, a NO scavenger), which was parallel with the expression of anthocyanin biosynthesis-related transcription factors and structural genes. All these results demonstrate that both H₂O₂ and NO are involved in UV-B-induced anthocyanin accumulation, and there is a crosstalk between them as well as a classical UVR8 pathway.

UV-B-induced anthocyanin accumulation in hypocotyls of radish sprouts continues in the dark after irradiation

BACKGROUND

Raphanus sativus L. cv. Yanghua sprouts are rich in health-promoting anthocyanins; thus hypocotyls show a red color under light. In this study, effects of UV-B irradiation at 5 W m(-2) on anthocyanin biosynthesis in the hypocotyls of radish sprouts were investigated.

RESULTS

Anthocyanins began to accumulate rapidly from 24 h irradiation and increased continuously until 48 h, showing a similar pattern to phenylalanine ammonia lyase (PAL) activity, with a correlation coefficient of 0.804. The expression of DFR and ANS paralleled the upward trend in anthocyanin accumulation, while CHS, CHI and F3H were upregulated before accumulation. When sprouts were moved into the dark from UV-B, the anthocyanin accumulation did not stop immediately. By contrast, anthocyanin accumulated continuously for more than 12 h in the dark, which was further supported by the significantly higher PAL activity monitored at 24 h after irradiation. Similarly, the transcript levels of anthocyanin biosynthesis-related genes were much higher over 6 h after 12 h UV-B irradiation.

CONCLUSION

UV-B-induced anthocyanin accumulation continues in the dark after irradiation, which was supported by unfading PAL activity and high levels of biosynthesis-related genes. This will provide evidence to produce high-quality sprouts with more anthocyanins but less energy wastage in practice.

Effects of Replacement of Concentrate Mixture by Broccoli Byproducts on Lactating Performance in Dairy Cows

The objective of the present study was to determine the effects of feeding pelletized broccoli byproducts (PBB) on milk yield and milk composition in dairy cows. In Trial 1, an in vitro gas test determined the optimal replacement level of PBB in a concentrate mixture in a mixed substrate with Chinese wild ryegrass hay (50:50, w/w) at levels of 0, 10%, 20%, 30%, or 40% (dry matter basis). When the concentrate was replaced by PBB at a level of 20%, no adverse effects were found on the gas volume or its rate constant during ruminal fermentation. In trial 2, 24 lactating cows (days in milk = 170.4±35; milk yield = 30±3 kg/d; body weight = 580 ±13 kg) were divided into 12 blocks based on day in milk and milk yield and randomly allocated to two dietary treatments: a basic diet with or without PBB replacing 20% of the concentrate mixture. The feeding trial lasted for 56 days; the first week allowed for adaptation to the diet. The milk composition was analyzed once a week. No significant difference in milk yield was observed between the two groups (23.5 vs 24.2 kg). A significant increase was found in milk fat content in the PBB group (p<0.05). Inclusion of PBB did not affect milk protein, lactose, total solids or solids-not-fat (p>0.05). These results indicated that PBB could be included in dairy cattle diets at a suitable level to replace concentrate mixture without any adverse effects on dairy performance.

Development of Combined Dry Heat and Chlorine Dioxide Gas Treatment with Mechanical Mixing for Inactivation of Salmonella enterica Serovar Montevideo on Mung Bean Seeds

Foodborne outbreaks have been associated with the consumption of fresh sprouted beans. The sprouting conditions of mung bean seeds provide optimal conditions of temperature and relative humidity for any potential pathogenic contaminant on the seeds to grow. The lack of a kill step postsprouting is a major safety concern. Thus, the use of a kill step on the seeds prior to a sprouting step would enhance the safety of fresh sprouts. The objective of this work was to evaluate the effectiveness of the combined thermal and chlorine dioxide gas (3.5 mg/liter of air) treatment with mechanical mixing (tumbling) to eliminate Salmonella on artificially inoculated mung bean seeds. Although no viable Salmonella was recovered from seeds treated in hot water at 60°C for 2 h, these treated seeds failed to germinate. Dry heat treatments (55, 60, or 70°C) for up to 8 h reduced Salmonella populations in excess of 3 log CFU/g. The use of tumbling, while treating the seeds, resulted in up to 1.6 log CFU/g reduction in Salmonella populations compared with no tumbling. Dry heat treatment at 65°C for 18 h with tumbling resulted in a complete inactivation of Salmonella populations on inoculated seeds with low inoculum levels (2.83 log CFU/g) as compared with high inoculum levels (4.75 log CFU/g). The increased reductions in pathogenic populations on the seeds with the use of tumbling could be attributed to increased uniformity of heat transfer and exposure to chlorine dioxide gas. All treated seeds were capable of germinating, as well as the nontreated controls. These results suggest that this combined treatment would be a viable process for enhancing the safety of fresh sprouts.

Cerium oxide nanoparticles alter the antioxidant capacity but do not impact tuber ionome in Raphanus sativus (L)

The effects of nCeO2 on food quality are not well known yet. This research was performed to determine the impact of nCeO2 on radish (Raphanus sativus L.). Plants were cultivated to full maturity in potting soil treated with nCeO2 at concentrations of 0, 62.5, 125, 250, and 500 mg/kg. Germination, growth, photosynthesis, ionome, and antioxidants were evaluated at different growth stages. Results showed that at 500 mg/kg, nCeO2 significantly retarded seed germination but did not reduce the number of germinated seeds. None of the treatments affected gas exchange, photosynthesis, growth, phenols, flavonoids, and nutrients' accumulation in tubers and leaves of adult plants. However, tubers' antioxidant capacity, expressed as FRAP, ABTS(•-) and DPPH, increased by 30%, 32%, and 85%, respectively, in plants treated with 250 mg nCeO2kg(-1) soil. In addition, cerium accumulation in tubers of plants treated with 250 and 500 mg/kg reached 72 and 142 mg/kg d wt, respectively. This suggests that nCeO2 could improve the radical scavenging potency of radish but it might introduce nCeO2 into the food chain with unknown consequences.

Evaluation of chlorine dioxide gas treatment to inactivate Salmonella enterica on mungbean sprouts

Although freshly sprouted beans and grains are considered to be a source of nutrients, they have been associated with foodborne outbreaks. Sprouts provide good matrices for microbial localization and growth due to optimal conditions of temperature and humidity while sprouting. Also, the lack of a kill step postsprouting is a major safety concern. The objective of this work was to evaluate the effectiveness of chlorine dioxide gas treatment to reduce Salmonella on artificially inoculated mungbean sprouts. The effectiveness of gaseous chlorine dioxide (0.5 mg/liter of air) with or without tumbling (mechanical mixing) was compared with an aqueous chlorine (200 ppm) wash treatment. Tumbling the inoculated sprouts during the chlorine dioxide gas application for 15, 30, and 60 min reduced Salmonella populations by 3.0, 4.0, and 5.5 log CFU/g, respectively, as compared with 3.0, 3.0, and 4.0 log CFU/g reductions obtained without tumbling, respectively. A 2.0 log CFU/g reduction in Salmonella was achieved with an aqueous chlorine wash. The difference in microbial reduction between chlorine dioxide gas versus aqueous chlorine wash points to the important role of surface topography, pore structure, bacterial attachment, and/or biofilm formation on sprouts. These data suggested that chlorine dioxide gas was capable of penetrating and inactivating cells that are attached to inaccessible sites and/or are within biofilms on the sprout surface as compared with an aqueous chlorine wash. Consequently, scanning electron microscopy imaging indicated that chlorine dioxide gas treatment was capable of penetrating and inactivating cells attached to inaccessible sites and within biofilms on the sprout surfaces.

Effect of light on quality and bioactive compounds in postharvest broccoli florets

The effect of light treatment (fluorescent and light-emitting diode (LED) green light) on shelf life, visual quality and bioactive compounds in broccoli florets was investigated. The results showed that light treatment extended shelf life and inhibited the decrease of H value and chlorophyll contents in broccoli florets stored at 25 °C. The content of total phenols and glucosinolates were markedly increased by LED green light, but no effect on sulforaphane. Fluorescent and LED green light treatment significantly increased DPPH radical scavenging activity in broccoli, but little effect was found between the two light treatments. These results indicated that LED green light could be a useful technique for extending shelf life, maintaining visual quality and preventing decrease of bioactive compounds in broccoli florets.

Comparison of the growth of Escherichia coli O157: H7 and O104: H4 during sprouting and microgreen production from contaminated radish seeds

Both sprouts and microgreens are popular tender produce items, typically grown and harvested in indoor facilities which allow a higher degree of control compared to open field production. While sprouts, which have frequently been implicated in foodborne illness outbreaks, are the subject of numerous national and international standards for their production and distribution, there is a lack of data pertaining to the microbiological safety of microgreens. In this study, sprouts and microgreens were produced from radish seeds inoculated with Escherichia coli O157: H7 or O104: H4 and E. coli populations on the harvested products compared to assess the potentials of product contamination from contaminated seeds during sprouting and microgreen production. Both E. coli O157:H7 and O104:H4 grew rapidly during sprouting, reaching levels of 5.8-8.1 log cfu/g and 5.2-7.3 log cfu/g, respectively, depending on the initial inoculation levels of the seeds (1.5-4.6 log cfu/g and 0.8-4.3 log cfu/g on radish seeds, respectively). In comparison, E. coli O157:H7 and O104:H4 populations on harvested microgreens ranged from 0.8 to 4.5 log cfu/g and from 0.6 to 4.0 log cfu/g, respectively. Although harvested microgreens carried significantly less (P < 0.001) E. coli than sprouts germinated from seeds inoculated at the same levels, proliferation of E. coli O157:H7 and O104:H4 occurred during both sprouting and microgreen growth.

Effect of sprouting and light cycle on antioxidant activity of Brassica oleracea varieties

The antioxidant activity of sprouts from four Brassica oleracea varieties was evaluated using "in vitro" methods (total phenolic and flavonoid content; radical scavenging assays: DPPH, hydroxyl and peroxyl; and Ferrous Ion-chelating Ability Assay). Light cycles and sprouting influenced the potential antioxidant activity of sprouts and significant differences were observed between varieties. Generally, antioxidant activity decreased with sprouting and increased in the presence of light, whose discriminant effect was highly significant (P<0.001). Red cabbage sprouts produced under light cycles showed the highest antioxidant activity (57.11 μg mL(-1) Ferrous Ion-chelating Ability, 221.46 μg mL(-1) Hydroxyl radical scavenging, 279.02 μg mL(-1) Peroxyl radical scavenging). Among the traditional Portuguese brassica varieties, Penca cabbage sprouts produced under light presented higher antioxidant capacity, and also higher phenolic and flavonoid content (54.04 mg GAEg(-1) d.w. extract and 21.33 QEg(-1) d.w. extract, respectively) than Galega kale. The phenolic content of Brassica sprouts had a significant contribution to the antioxidant capacity.

O risco das aminas biogênicas nos alimentos

Aminas biogênicas são bases orgânicas de baixo peso molecular com atividade biológica, produzidas a partir da ação da enzima descarboxilase. Microrganismos utilizados na fermentação de alimentos são capazes de produzi-las. O consumo desses compostos causam graves efeitos toxicológicos, indesejáveis para a saúde humana. Embora não exista legislação específica sobre a quantidade máxima permitida de aminas em alimentos e bebidas, a presença e o acumulo destes compostos é de grande importância. O objetivo desta revisão é evidenciar a necessidade de mais estudos e discutir a presença de aminas biogênicas em alimentos variados.

Health effects and occurrence of dietary polyamines: a review for the period 2005-mid 2013

This review continues a previous one (Kalač & Krausová, 2005). Dietary polyamines spermidine and spermine participate in an array of physiological roles with both favourable and injurious effects on human health. Dieticians thus need plausible information on their content in various foods. The data on the polyamine contents in raw food materials increased considerably during the reviewed period, while information on their changes during processing and storage have yet been fragmentary and inconsistent. Spermidine and spermine originate mainly from raw materials. Their high contents are typical particularly for inner organs and meat of warm-blooded animals, soybean and fermented soybean products and some mushroom species. Generally, polyamine contents range widely within the individual food items.

6-Benzylaminopurine delays senescence and enhances health-promoting compounds of harvested broccoli

The effect of 6-benzylaminopurine (6-BA) on the color, antioxidant activity, and contents of total phenols, glucosinolate, and sulforaphane in broccoli florets was investigated. The results showed that 6-BA treatment markedly inhibited the increase of the L* value and malondialdehyde (MDA) content and retarded the decrease of the H value. 6-BA treatment reduced the rate of chlorophyll degradation by regulating the activities of chlorophyllase and Mg-dechelatase. When compared to control florets, the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity and the activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT) were enhanced in florets treated with 6-BA, whereas the activity of peroxidase (POD) was significantly reduced. The contents of total phenols, glucosinolate, and sulforaphane in broccoli florets were also profoundly increased after treatment with 6-BA. These results indicated that 6-BA could maintain the quality, delay senescence, and improve the nutritional value of broccoli.

Microbiological examination of vegetable seed sprouts in Korea

Sprouted vegetable seeds used as food have been implicated as sources of outbreaks of Salmonella and Escherichia coli O157:H7 infections. We profiled the microbiological quality of sprouts and seeds sold at retail shops in Seoul, Korea. Ninety samples of radish sprouts and mixed sprouts purchased at department stores, supermarkets, and traditional markets and 96 samples of radish, alfalfa, and turnip seeds purchased from online stores were analyzed to determine the number of total aerobic bacteria (TAB) and molds or yeasts (MY) and the incidence of Salmonella, E. coli O157:H7, and Enterobacter sakazakii. Significantly higher numbers of TAB (7.52 log CFU/g) and MY (7.36 log CFU/g) were present on mixed sprouts than on radish sprouts (6.97 and 6.50 CFU/g, respectively). Populations of TAB and MY on the sprouts were not significantly affected by location of purchase. Radish seeds contained TAB and MY populations of 4.08 and 2.42 log CFU/g, respectively, whereas populations of TAB were only 2.54 to 2.84 log CFU/g and populations of MY were 0.82 to 1.69 log CFU/g on alfalfa and turnip seeds, respectively. Salmonella and E. coli O157:H7 were not detected on any of the sprout and seed samples tested. E. sakazakii was not found on seeds, but 13.3% of the mixed sprout samples contained this potentially pathogenic bacterium.