27 research outputs found
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Surfactant TWEEN20 provides stabilisation effect on anthocyanins extracted from red grape pomace
Red grape pomace, a wine-making by-product is rich in anthocyanins and has many applications in food and pharmaceutical industry. However, anthocyanins are unstable during processing and storage. This study aimed to investigate the stability of anthocyanins obtained by hydroalcoholic extraction (with and without sorbic acid) and colloidal gas aphrons (CGA) separation; a surfactant (TWEEN20) based separation. Anthocyanins in CGA samples showed higher stability (half-life = 55 d) than in the crude extract (half-life = 43 d) and their stability increased with the concentration of TWEEN20 in the CGA fraction (6.07–8.58 mM). The anthocyanins loss in the CGA sample (with the maximum content of surfactant, 8.58 mM) was 34.90%, comparable to that in the crude ethanolic extract with sorbic acid (EE-SA) (31.53%) and lower than in the crude extract (44%). Colour stabilisation was also observed which correlated well with the stability of individual anthocyanins in the EE and CGA samples. Malvidin-3-o-glucoside was the most stable anthocyanin over time
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The use of asparaginase to reduce acrylamide levels in cooked food
Strategies proposed for reducing the formation of the suspected carcinogen acrylamide in cooked foods often rely on a reduction in the extent of the Maillard reaction, in which acrylamide is formed from the reaction between asparagine and reducing sugars. However, the Maillard reaction also provides desirable sensory attributes of cooked foods. Mitigation procedures that modify the Maillard reaction may negatively affect flavour and colour. The use of asparaginase to convert asparagine to aspartic acid may provide a means to reduce acrylamide formation, while maintaining sensory quality. This review collates research on the use of enzymes, asparaginase in particular, to mitigate acrylamide formation. Asparaginase is a powerful tool for the food industry and it is likely that its use will increase. However, the potential adverse effects of asparaginase treatment on sensory properties of cooked foods and the need to achieve sufficient enzyme–substrate contact remain areas for future research
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Assessment of antimicrobial activity, mode of action and volatile compounds of etlingera pavieana essential oil
Etlingera pavieana (Pierre ex Gagnep.) R.M.S. is a rhizomatous plant in the Zingiberaceae family which could be freshly eaten, used as a condiment or as a traditional remedy. Our work investigated the chemical composition and antimicrobial activity of the E. pavieana essential oils extracted from the rhizome (EOEP). We extracted the EOEP from the rhizome by hydrodistillation and analyzed the chemical composition by headspace solid-phase microextraction coupled with gas chromatography/mass spectrometry (HS-SPME-GC/MS). A total of 22 volatile compounds were identified where trans-anethole (78.54%) and estragole (19.36%) were the major components in the EOEP. The antimicrobial activity of EOEP was evaluated based on the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) values using the broth dilution method and enumerating cell death overtime. Our work shows that the EOEP exhibits potent antibacterial activity against foodborne pathogenic Gram-positive bacteria, namely Bacillus cereus, Staphylococcus aureus and Listeria monocytogenes in the range of 0.1–0.3% (v/v). We further investigated the mechanism of EOEP inhibition using Synchrotron Fourier transformation infrared (FTIR) microspectroscopy. Here, we show significant differences in DNA/nucleic acid, proteins and cell membrane composition in the bacterial cell. To conclude, EOEP exhibited antimicrobial activity against foodborne pathogens, especially the Gram-positive bacteria associated with ready-to-eat (RTE) food and, thus, has the potential to serve as a natural preservative agent in RTE products
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Detrimental effect on the gut microbiota of 1,2-dicarbonyl compounds after in vitro gastro-intestinal and fermentative digestion
This study, investigated the stability of dicarbonyl compounds (DCs), 3-deoxyglucosone (3-DG), glyoxal (GO) and methylglyoxal (MGO) during simulated gastrointestinal
digestion processes and the impact these compounds have on the gut microbiota. DCs pass almost unaltered through the in-vitro gastrointestinal digestion phases (concentration loss: 11% for 3-DG, 24% for GO and MGO) and have an effect on the fermentative digestion process, reducing the total gut bacterial population up to 6 Log10 units. Previous studies have shown no antimicrobial activity for 3-DG, however, for the first time it has been shown that when incubated with faecal bacteria 3-DG strongly
depressed this microbial community.
The influence of dicarbonyl compounds on the anaerobic fermentation processes was confirmed by the reduced production of short-chain fatty acids. Considering the modern Western diet, characterised by high consumption of ultra-processed foods rich in dicarbonyl compounds, this could lead to a reduction of bacteria important for the
microbiome
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Influence of sugar type on the bioavailability of cocoa flavanols.
The beneficial effects of cocoa on vascular function are mediated by the absorption of monomeric flavanols into the circulation from the small intestine. As such, an understanding of the impact of the food matrix on the delivery of flavanols to the circulation is critical in assessing the potential vascular impact of a food. In the present study, we investigated the impact of carbohydrate type on flavanol absorption and metabolism from chocolate. A randomised, double-blind, three-arm cross-over study was conducted, where fifteen volunteers were randomly assigned to either a high-flavanol (266 mg) chocolate containing maltitol, a high-flavanol (251 mg) chocolate with sucrose or a low-flavanol (48 mg) chocolate with sucrose. Test chocolates were matched for micro- and macronutrients, including the alkaloids theobromine and caffeine, and were similar in taste and appearance. Total flavanol absorption was lower after consumption of the maltitol-containing test chocolate compared with following consumption of its sucrose-containing equivalent (P = 0·002). Although the O-methylation pattern observed for absorbed flavanols was unaffected by sugar type, individual levels of unmethylated ( - )-epicatechin metabolites, 3'-O-methyl-epicatechin and 4'-O-methyl-epicatechin metabolites were lower for the maltitol-containing test chocolate compared with the sucrose-containing equivalent. Despite a reduction in the total plasma pool of flavanols, the maximum time (T max) was unaffected. The present data indicate that full assessment of intervention treatments is vital in future intervention trials with flavanols and that carbohydrate content is an important determinant for the optimal delivery of flavanols to the circulation
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Identification and quantification of glucosinolate and flavonol compounds in rocket salad (Eruca sativa, Eruca vesicaria and Diplotaxis tenuifolia) by LC–MS: highlighting the potential for improving nutritional value of rocket crops
Liquid Chromatography Mass Spectrometry (LC-MS) was used to obtain glucosinolate and flavonol content for 35 rocket accessions and commercial varieties. 13 glucosinolates and 11 flavonol compounds were identified. Semi-quantitative methods were used to estimate concentrations of both groups of compounds. Minor glucosinolate composition was found to be different between accessions; concentrations varied significantly. Flavonols showed differentiation between genera, with Diplotaxis accumulating quercetin glucosides and Eruca accumulating kaempferol glucosides. Several compounds were detected in each genus that have only previously been reported in the other. We highlight how knowledge of phytochemical content and concentration can be used to breed new, nutritionally superior varieties. We also demonstrate the effects of controlled environment conditions on the accumulations of glucosinolates and flavonols and explore the reasons for differences with previous studies. We stress the importance of consistent experimental design between research groups to effectively compare and contrast results
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Mediation of coffee-induced improvements in human vascular function by chlorogenic acids and its metabolites: two randomized, controlled, crossover intervention trials
Background & aims
Polyphenol intake has been linked to improvements in human vascular function, although data on hydroxycinnamates, such as chlorogenic acid (CGA) have not yet been studied. We aimed to investigate the impact of coffee intake rich in chlorogenic acid on human vascular function and whether CGAs are involved in potential effects.
Methods
Two acute randomized, controlled, cross-over human intervention trials were conducted. The impact of coffee intake, matched for caffeine but differing in CGA content (89, and 310 mg) on flow-mediated dilation (FMD) was assessed in 15 healthy male subjects. In a second intervention trial conducted with 24 healthy male subjects, the impact of pure 5-caffeoylquinic acid (5-CQA), the main CGA in coffee (5-CQA; 450 mg and 900 mg) on FMD was also investigated.
Results
We observed a bi-phasic FMD response after low and high polyphenol, (89 mg and 310 mg CGA) intake, with increases at 1 (1.10 ± 0.43% and 1.34 ± 0.62%, respectively) and 5 (0.79% ± 0.32 and 1.52% ± 0.40, respectively) hours post coffee consumption. FMD responses to coffee intake was closely paralleled by the appearance of CGA metabolites in plasma, notably 3-, 4- and 5-CQA and ferulic-4′-O-sulfate at 1 h and isoferulic-4′-O-glucuronide and ferulic-4′-O-sulfate at 5 h. Intervention with purified 5-CQA (450 mg) also led to an improvement in FMD response relative to control (0.75 ± 1.31% at 1 h post intervention, p = 0.06) and concomitant appearance of plasma metabolites.
Conclusions
Coffee intake acutely improves human vascular function, an effect, in part, mediated by 5-CQA and its physiological metabolites
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Oxidative discolouration in whole-head and cut lettuce: biochemical and environmental influences on a complex phenotype and potential breeding strategies to improve shelf-life
Lettuce discolouration is a key post-harvest trait. The major enzyme controlling oxidative discolouration
has long been considered to be polyphenol oxidase (PPO) however, levels of PPO and subsequent development of discolouration symptoms have not always correlated. The predominance of a latent state of the enzyme in plant tissues combined with substrate activation and contemporaneous suicide inactivation
mechanisms are considered as potential explanations for
this phenomenon. Leaf tissue physical properties have
been associated with subsequent discolouration and
these may be influenced by variation in nutrient
availability, especially excess nitrogen and head maturity at harvest. Mild calcium and irrigation stress has
also been associated with a reduction in subsequent
discolouration, although excess irrigation has been
linked to increased discolouration potentially through
leaf physical properties. These environmental factors,
including high temperature and UV light intensities,
often have impacts on levels of phenolic compounds
linking the environmental responses to the biochemistry
of the PPO pathway. Breeding strategies targeting the
PALand PPOpathway biochemistry and environmental
response genes are discussed as a more cost-effective
method of mitigating oxidative discolouration then
either modified atmosphere packaging or post-harvest
treatments, although current understanding of the
biochemistry means that such programs are likely to
be limited in nature and it is likely that they will need to be deployed alongside other methods for the foreseeable future
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Modelling extraction kinetics of betalains from freeze dried beetroot powder into aqueous ethanol solutions
The extraction kinetics of betalains (betacyanin and betaxanthin) from freeze dried beetroot powder into aqueous ethanol solutions is modelled by considering the concentration of a given betalain at any given time to result from a balance between the rate of its release from the solid phase and the rate of its chemical degradation in the extract phase. The mathematical model obtained shows that the concentration of the betalain peaks before progressively decreasing with time. The model was experimentally validated for various combinations of temperature (55-85 °C), ethanol concentration (10-30%) and particle size (120-300 µm). The ratio of betacyanin to betaxanthin in the liquid phase was approximately 1 over the duration of extraction at 55 and 65 °C. However, the ratio decreased at the higher temperatures of 75 and 85 °C. A maximum productivity rate of a given betalain was defined as its peak concentration divided by the time taken to reach the peak concentration, which was found to be relatively insensitive to the ethanol concentration below 75 °C