Integral valorisation of tomato by-products towards bioactive compounds recovery: Human health benefits.

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.

Anthocyanin extraction from plant tissues: A review.

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.

Bacteria immobilisation on hydroxyapatite surface for heavy metals removal.

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.

Evaluation of antimicrobial edible coatings from a whey protein isolate base to improve the shelf life of cheese.

The objective of this work was to evaluate the effectiveness of antimicrobial edible coatings to wrap cheeses, throughout 60 d 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.

Bioconversion of oleuropein to hydroxytyrosol by lactic acid bacteria.

The aim of this work is to study the conversion of oleuropein-a polyphenol present in olives and olive oil by-products-into hydroxytyrosol, a polyphenol with antioxidant and antibacterial properties. The hydrolysis reaction is performed by lactic acid bacteria. Six bacterial strains (Lactobacillus plantarum 6907, Lactobacillus paracasei 9192, Lactobacillus casei, Bifidobacterium lactis BO, Enterococcus faecium 32, Lactobacillus LAFTI 10) were tested under aerobic and anaerobic conditions. The oleuropein degradation and hydroxytyrosol formation were monitored by HPLC. Results showed that oleuropein could be successfully converted into hydroxytyrosol. The most effective strain was Lactobacillus plantarum 6907, with a reaction yield of hydroxytyrosol of about 30 %. Different reaction mechanisms were observed for different microorganisms; a different yield was observed for Lactobacillus paracasei 9192 under aerobic or anaerobic conditions and an intermediate metabolite (oleuropein aglycone) was detected for Lactobacillus paracasei 9192 and Lactobacillus plantarum 6907 only. This study could have significant applications, as this reaction can be used to increase the value of olive oil by-products and/or to improve the taste of unripe olives.

Use of response surface methodology to optimize protease synthesis by a novel strain of Bacillus sp. isolated from Portuguese sheep wool.

AIMS: To investigate the influence of yeast extract, peptone, temperature and pH upon protease productivity by Bacillus sp. HTS102--a novel wild strain isolated from wool of a Portuguese sheep breed (Merino). METHODS AND RESULTS: A 2(4) full factorial, central composite design together with response surface methodology was used to carry out the experiments and analyse the results, respectively. Among the individual parameters tested, temperature and peptone concentration produced significant effects upon protease productivity. A high correlation coefficient (R(2 ) = 0·994, P < 0·01) indicated that the empiric second-order polynomial model postulated was adequate to predict said productivity, with the optimum loci characterized by: temperature of 43°C, peptone content of 1·4 g l(-1) , pH of 5·1 and yeast extract concentration of 10·0 g l(-1) . CONCLUSIONS: Protease synthesis depends chiefly on temperature and peptone level. The maximum protease activity was more than twice that obtained with the basal medium, so the experimental design and analysis undertaken were effective towards process optimization. SIGNIFICANCE AND IMPACT OF THE STUDY: Rational choice of processing conditions for maximum protease productivity will be relevant if an economically feasible fermentation process based on Bacillus sp. HTS102 is intended.

Chitosan: antimicrobial action upon staphylococci after impregnation onto cotton fabric.

BACKGROUND: High levels of viable Staphylococcus aureus, which are often found on inflamed skin surfaces, are usually associated with atopic dermatitis. Textiles, owing to their high specific surface area and intrinsic hydrophilicity, retain moisture while also providing excellent environmental conditions for microbial growth and proliferation. Recently, a number of chemicals have been added to textiles, so as to confer antimicrobial activity. AIMS: To evaluate the antimicrobial action of chitosan upon selected skin staphylococci. METHODS AND RESULTS: We isolated staphylococci from normal skin of 24 volunteers and studied their survival upon contact with chitosan-impregnated cotton fabric. Low and high molecular weight chitosans were used at two concentrations; all four did effectively reduce the growth of some staphylococci (namely Staph. aureus), by up to 5 log cycles, thus unfolding a potential towards control and even prevention of related skin disorders. CONCLUSION: Our data suggest an effective, but selective antibacterial action of chitosans towards skin bacteria. SIGNIFICANCE AND IMPACT OF THE STUDY: The possibility to use a natural biopolymer incorporated in a textile to alleviate and even treat some of the symptoms associated with this skin condition may raise an alternative to existing medical treatments. The selectivity observed prevents full elimination of bacteria from the skin surface, which is an advantage.

Effects of extracts of selected medicinal plants upon hepatic oxidative stress.

Aqueous extracts of a few medicinal plants traditionally used in Portugal have been assayed for their effects upon hepatic oxidative stress in mice. Previous in vitro studies had allowed characterization of agrimony, sage, savory, and raspberry in terms of overall antioxidant capacity and phenolic content. In the present study, the antioxidant effect and safety of these four plants were evaluated in vivo. For this purpose, mice ingested extracts in aqueous form (or water, used as the control) for 4 weeks; damage to lipids, proteins, and DNA was evaluated by oxidative cell biomarkers by the end of that period. Levels of hepatic glutathione and activities of enzymes involved in metabolism thereof were also determined. Finally, catalase and superoxide dismutase (SOD) activities were quantified, as these enzymes play a crucial role in antioxidant defense. When compared with the control, both raspberry and savory produced significant lipid protection; however, protein damage was significantly lower only in raspberry-treated animals. On the other hand, DNA damage was prevented only by savory. All plants led to a decrease in catalase activity, whereas all but sage also produced a decrease in SOD activity. With regard to glutathione levels and activities of enzymes involved in its metabolism, the aforementioned extracts exhibited different effects. In general, raspberry appeared to be the most promising extract, followed by savory, sage, and agrimony, sorted by decreasing performance in protection; the latter was even slightly toxic. Hence, the plants tested possess compounds with interesting biological activities that may support eventual inclusion in food or feed as functional additives.

Invited review: physiological properties of bioactive peptides obtained from whey proteins.

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.

Activity of adventitious Enterococcus strains on model curdled caprine milk: microbial growth and evolution of concentration of organic acids and lactose throughout time.

Enterococci offer a few unique advantages when compared with other lactic acid bacteria in that they are resistant to phages, stable lactose fermenters, tolerant to relatively high concentrations of sodium chloride and optimal growers at relatively high temperatures (Franz et al., 1999). Such genus occurs and grows in a variety of cheeses, especially artisanal cheeses produced in Southern Europe usually from raw milk; they are claimed to play a major role in ripening and aroma development in such cheeses (Freitas et al., 1995; Macedo et al., 1995). Enterococci can produce lactic, acetic, propionic and succinic acids (Ocando et al., 1994), compounds that have been correlated with flavor characteristics of cheese; hence strains of Enterococcus have been successfully used as starters for different cheese (Franz et al., 1999).

Characterization of whey cheese packaged under vacuum.

Vacuum packaging was assayed at 4 degrees C and was tested in comparison to unpackaged counterparts, in both microbiological and physicochemical terms, in studies pertaining to the preservation of Requeijão, a traditional Portuguese whey cheese. Bacteria were absent (i.e., <10 CFU/g) in whey cheeses on the day of manufacture as a result of thermal processing. After storage, both unpackaged and packaged cheeses exhibited high viable counts of Bacillus, Pseudomonas, Enterobacteriaceae, and lactic acid bacteria (especially lactococci). Yeasts, staphylococci, enterococci, and spore-forming clostridia were severely inhibited by the package vacuum combined with the increasing acidification developed therein. Whey cheeses packaged under vacuum underwent substantial acidification, slight depletion of lactose, and no significant variation in moisture content or texture; conversely, unpackaged whey cheeses exhibited substantial loss of water and a concomitant increase in rigidity. Vacuum packaging strongly inhibited lipolysis (even if viable counts of some microbial groups were high); saturated fatty acids (mainly C16:0 and C14:0) accounted for ca. 73% of the total free-fatty acid content, whereas the most concentrated unsaturated fatty acids were C18:1 and C18:2 (ca. 14% each). The conclusions generated in our study are, in general, useful for a wide range of whey cheeses worldwide: i.e., Requéson (Spain), Ricotta (Italy), Broccio (France), and Anthotyro (Greece). In addition, our conclusions are particularly helpful in terms of improving the safety of Requeijão, a widely acclaimed dairy specialty.