Anthocyanins have gathered the attention of the scientific community mostly due to their vast range of possible applications. They have been the center point of the research in many different fields, ...among which is food development, where their innate coloring, antioxidant capacity, and biological potential open interesting venues to the development of new food additives and functional foodstuffs. As the range of application grows, so does the necessity to obtain these compounds, and since they are naturally occurring, the most common way to obtain anthocyanins is to extract them from different plant sources, such as fruits and flowers. Several efforts have been made to develop methods that allow for better extraction yields and higher purification rates therefore this review aims to compile the information regarding extraction and purification procedures in a comprehensive manner.
•MRS medium is the major source of interfering compounds.•MRS medium was responsible for the introduction of glucose-rich material.•Lactose may promote the co-precipitation of several medium ...components.•YE also contributed with mannoproteins.•TCA method was shown to be more efficient in recovery of EPS.
De-Man Rogosa and Sharpe (MRS) is a complex medium commonly used to obtain exopolysaccharides (EPS) from lactic acid bacteria. However, the various nutrients (carbon and nitrogen sources) of media and supplements added to enhance the bacterial growth and EPS production, may interfere with the purification of the extracts resulting in an over-estimation of the EPS and erroneous structural assignments. The efficiency of trichloroacetic acid (TCA)/pronase and 5-sulfosalicylic acid – SSA methods was evaluated. In addition, the interference of the major MRS broth components as well as lactose was evaluated using xanthan gum as model control EPS. It was concluded that MRS medium is a major source of interfering compounds in the quantification of EPS, mainly glucose-rich material and to a lesser extent mannoproteins from yeast extract. This effect was found to be potentiated by the presence of lactose. TCA/pronase method was shown to be more efficient in eliminating interferents.
Processing of whey proteins yields several bioactive peptides that can trigger physiological effects in the human body: on the nervous system via their opiate and ileum-contracting activities; on the ...cardiovascular system via their antithrombotic and antihypertensive activities; on the immune system via their antimicrobial and antiviral activities; and on the nutrition system via their digestibility and hypocholesterolemic effects. The specific physiological effects, as well the mechanisms by which they are achieved and the stabilities of the peptides obtained from various whey fractions during their gastrointestinal route, are specifically discussed in this review.
Aims
Chitosan is a natural compound that has been validated as a viable antimicrobial agent against Staphylococcus aureus. With this work we sought to evaluate the planktonic and sessile sensitivity ...of methicillin‐resistant S. aureus to chitosan's activity and evaluate if methicillin‐resistant S. aureus (MRSA) would be more or less sensitive to chitosan's activity than methicillin‐sensitive S. aureus (MSSA).
Methods and Results
A group comprised of reference strains and clinical multiresistant isolates of MSSA and MRSA were used. Methicilin resistance effect upon chitosan activity was assessed in planktonic setting and in different phases of sessile colonization, namely adhesion, biofilm formation and mature biofilm through biomass and metabolism inhibition. The results obtained showed that S. aureus methicillin resistance mechanism did not impair chitosan's activity as the highest bacterial susceptibility was registered for MRSA. Chitosan was highly effective in inhibiting MSSA and MRSA strains in both planktonic and sessile settings with biofilm inhibition percentages reaching as high as 90% for MRSA.
Conclusions
Staphylococcus aureus methicillin resistance did not impair chitosan's antimicrobial and antibiofilm activities and MRSA and MSSA were inhibited both in planktonic and sessile settings at low concentrations with great efficacy.
Significance and Impact of the Study
Considering the obtained results chitosan shows potential as an alternative for the control of biofilm‐related recalcitrant MRSA infections.
Aims
The present work aimed to characterize the impact of an anthocyanin‐rich blueberry extract upon the growth, adhesion and biofilm formation of several pathogens including some multiresistant ...bacteria.
Methods and Results
A group comprised of reference strains and clinical multiresistant isolates of Pseudomonas aeruginosa, Escherichia coli, Proteus mirabilis, Acinetobacter baumannii and Staphylococcus aureus, were used to screen for antimicrobial activity. Microbial growth was determined through the measurement of the optical density while adhesion and biofilm formation was determined using the standard crystal violet staining procedure. The results showed that, while blueberry extract was only effective in hindering the growth of Staph. aureus and E. coli, it was capable of significantly inhibiting biofilm formation and bacterial adhesion for all micro‐organisms tested.
Conclusions
The extract demonstrated a considerable potential as a natural, alternative antimicrobial capable of either interfering with microbial growth or hamper the adhesion to surfaces, with Staph. aureus proving to be the most susceptible micro‐organism.
Significance and Impact of the Study
The overall study demonstrates the potential of anthocyanin extracts as natural effective alternative antimicrobial agents. Additionally, the extract's capacity to reduce adhesion without reducing bacterial growth reduces the likeliness of resistance development while reducing the probability of infection.
Selected bacterial strains were immobilised on the surface of hydroxyapatite (Ca10(PO4)6(OH)2 – HAp) of natural origin (fish bones). The capacity of the material, alone and in combination with the ...bacterial strains to act as heavy metal removers from aqueous streams was assessed. Pseudomonas fluorescens (S3X), Microbacterium oxydans (EC29) and Cupriavidus sp. (1C2) were chosen based on their resistance to heavy metals and capacity of adsorbing the metals.
These systems were tested using solutions of Zn(II), Cd(II) and in solutions containing both metals. A synergistic effect between the strains and HAp, which is effective in removing the target heavy metals on its own, was observed, as the combination of HAp with the bacterial strains led to higher adsorption capacity for both elements.
For the solutions containing only one metal the synergistic effect was greater for higher metal concentrations; 1C2 and EC29 were the most effective strains for Zn(II) and Cd(II) respectively, while S3X was less effective. Overall, an almost four-fold increase was observed for the maximum adsorption capacity for Zn(II) when 1C2 was employed – 0.433 mmol/g in comparison of 0.121 mmol/g for the unmodified HAp. For Cd(II), on the other hand, an almost three-fold increase was registered with EC29 bacterial strain – 0.090 vs 0.036 mmol/g for the unmodified HAp. When the solutions containing both metals were tested, the effect was more marked for lower concentrations.
► Bacterial strains were successfully immobilised on a hydroxyapatite (HAp) surface. ► The combined HAp + bacteria systems were used for removal of Zn(II) and Cd(II). ► The removal efficiency was higher for both metals if compared with unmodified HAp. ► Different strains showed different abilities for metals removal.
The objective of this work was to evaluate the effectiveness of antimicrobial edible coatings to wrap cheeses, throughout 60d of storage, as an alternative to commercial nonedible coatings. Coatings ...were prepared using whey protein isolate, glycerol, guar gum, sunflower oil, and Tween 20 as a base matrix, together with several combinations of antimicrobial compounds—natamycin and lactic acid, natamycin and chitooligosaccharides (COS), and natamycin, lactic acid, and COS. Application of coating on cheese decreased water loss (~10%, wt/wt), hardness, and color change; however, salt and fat contents were not significantly affected. Moreover, the antimicrobial edible coatings did not permit growth of pathogenic or contaminant microorganisms, while allowing regular growth of lactic acid bacteria throughout storage. Commercial nonedible coatings inhibited only yeasts and molds. The antimicrobial edible coating containing natamycin and lactic acid was the best in sensory terms. Because these antimicrobial coatings are manufactured from food-grade materials, they can be consumed as an integral part of cheese, which represents a competitive advantage over nonedible coatings.
This study evaluated the effects of a fibre and phenolic‐rich flour (IGF) prepared from Isabel grape by‐products on the growth and metabolism of different probiotics and distinct bacterial ...populations part of the human intestinal microbiota during an in vitro colonic fermentation. IGF was submitted to simulated gastrointestinal digestion before use in the experiments. IGF favoured the growth of the probiotics Lactobacillus acidophilus La‐05, L. casei L‐26 and Bifidobacterium lactis Bb‐12, with viable counts of >7 log CFU per ml, as well as caused decreases in pH values and increases in organic acid production in the growth medium during 48 h of cultivation. IGF increased the population of beneficial micro‐organisms forming the human intestinal microbiota, particularly Lactobacillus spp., decreased the pH values, and increased the lactic acid and short‐chain fatty acid (acetic, butyric and propionic acids) production during 24 h of in vitro colonic fermentation. These results indicate the potential prebiotic effects of IGF, which should represent a novel sustainable added‐value ingredient with functional properties and gut‐health benefits.
Significance and Impact of the Study: Isabel grape by‐products are rich in dietary fibres and phenolic compounds. Using these materials to elaborate a flour should be a strategy to produce ingredients with a high added value linked to an emerging zero waste approach in the agroindustry. Isabel grape flour (IGF) elaborated in this study had stimulatory effects on distinct probiotic strains. It caused overall beneficial effects on human intestinal microbiota in vitro, characterizing this product as a potential candidate for use as a prebiotic ingredient to formulate functional foods and dietary supplements.
•Tomato processing generates a considerable amount of valuable by-products.•Tomato by-products can emerge as a potential source of bioactive compounds (BC).•Green technologies can recover these ...high-added-value compounds.•Compounds’ bioaccessibility could be affected by technology recovery.•BC contain anti-inflammatory, antioxidant, and chemopreventive properties.
The tomato processing industry is one of the world's most important markets. This industry aims to optimise production, minimise energy costs and waste streams while ensuring high-quality products. This sector produces substantial amounts of by-products frequently disposed of as waste rather than reintroducing them with a new intent into the supply chain. However, these by-products are rich in bioactive compounds (BC), including carotenoids, fibre, which exhibit antioxidant, anti-inflammatory and chemopreventive properties, and cardiovascular protection. Reusing these compounds is favourable to reducing the environmental impact and enables the development of added-value products with various possible uses such as food and feed additives, nutraceuticals, cosmeceuticals, etc. This review summarises relevant issues towards the recovery and valorisation of BC from industrial tomato by-products within a circular economy context.
As blueberries are rich in phenolic compounds, which possess a demonstrated antimicrobial activity, it may be interesting to further elucidate its real potential and properties. As such, the main ...goal of this work was to evaluate the potential antimicrobial activity of Vaccinium corymbosum dry fruits and leaves aqueous extracts against several contaminants/pathogenic microorganisms while at the same time assessing the effect of V. corymbosum over lactic acid bacteria.
•Food contaminants and pathogens were was inhibited.•Both fruit and leaf extracts presented inhibition.•Lactic acid bacteria were not inhibited.
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