Search

The quality of protein is based on their amino acid composition, especially on the content and availability of essential amino acids. Cereals are important sources of protein for human nutrition, but are limited in the amounts of essential amino acids, notably lysine. The aim of this study was to analyze the chemical composition and amino acid profiles of different cereals that are important for nutritional purposes in human diet. The content of protein, moisture and crude fat in cereals varied significantly from 7.83 to 13.22%, 11.45 to 13.80%, and from 1.67 to 6.35%, respectively. The obtained results showed that oat had the highest contents of crude protein (13.22%), crude fat (6.35%) and crude cellulose (9.42%) compared to other cereals. Significant (p < 0.05) variation existed in the content of essential and nonessential amino acids among samples with the highest level in oat and wheat. Essential amino acids accounted for one-third of the total amino acids in the tested cereals. Glutamic acid was found to be the most abundant amino acid. It could be concluded that the amino acid composition of oat is the most favorable among cereals due to its high protein content and the content of lysine which can be found in limited amounts in most of the cereals.

A serious global problem with the increasing resistance of microorganisms to currently used antimicrobials has opened up the promotional research in the identification of new, more effective drugs with a broad spectrum of antimicrobial activities. Plant essential oils, due to the large biological and structural diversity of their components, are known to have many potential benefits. This study aimed to evaluate the antimicrobial and anti-adhesion activity of fifteen essential oils and their compounds against two bacterial and two yeast species responsible for food spoilage and infectious diseases. Antimicrobial activity was determined by testing the minimum inhibitory concentration (MIC), the minimum bactericidal concentration (MBC) and the minimum fungicidal concentration (MFC) of essential oils and compounds. The essential oils of Cinnamomum zeylanicum and Eugenia caryophyllus showed the highest antimicrobial activity with MICs ranging from 0.078 to 1.25 mg/mL, and 0.039 to 1.25 mg/mL, respectively. On the other hand, essential oils of Eucalypti aetheroleum and Salvia officinalis had significantly weaker antimicrobial properties than the others. Further, MICs were used to assess the inhibition of adhesion of bacteria Salmonella Typhimurium ATCC 25923 and Staphylococcus aureus ATCC 14208, and yeasts Candida albicans ATCC 10231 and Saccharomyces cerevisiae ATCC 9763 in a microtiter plate using the crystal violet staining method. Based on the percentage of adhesion inhibition, yeast S. cerevisiae ATCC 9763 showed a high level of antimicrobial resistance. E. caryophyllus had the strongest effect with inhibition up to 73%. Consistent with the antimicrobial susceptibility results, the most active anti-adhesion compounds were carvacrol and thymol. Considering the role of biofilm in food spoilage and clinical diseases, inhibition of the initial phase of biofilm formation by natural antimicrobial agents may be an alternative to commonly used synthetic ones.

A global increase in the demand for livestock products suggests that there will be a consequent rise in demand for feed, not only of cereals but of other feeds and particularly proteins. In the present study, oil industry by-products such as soybean meal, soybean cake and sunflower meal were analysed as sources of amino acids in animal nutrition. From among oilseed byproducts, the soybean meal content the most of crude protein up to 44% and the best of amino acid composition, while content of crude cellulose (about 6%) is lower in comparison to other oilseed meals. The results showed that the total amino acids in the examined samples ranged from 31.87 to 41.01%, and the total essential and nonessential amino acids varied from 13.41 to 17.38% and from 18.46 to 23.76%, respectively. Generally, the protein contained in soybean meal and cake was rich in essential amino acids. However, because of the lowest amino acid score, methionine was considered as a limiting amino acid in both soybean by-products. On the other hand, soya's meal contained higher level of lysine than other protein-based vegetable alternative to soya like sunflower meals examined in this study. Glutamic acid, aspartic acid, leucine and valine were the most abundant amino acids in all tested by-products of the oil industry. Therefore, partial substitution of protein sources in feeds with proteins from the oil industry by-products may improve feed quality.

In this work, the possibility of obtaining biopolymer films from Camelina sativa oilseed cake (CSoC) at different parameters of the synthesis process was investigated. The pH (values 8, 10, and 12), the temperature (60, 80, and 100 °C), and the concentration of the cake in the film-forming suspension (3, 4, and 5%) were varied. The films obtained were characterized by studying the mechanical, barrier, physico-chemical, structural, and biological properties (antioxidant and antimicrobial). The results showed moderate mechanical properties, indicating the application of these biopolymer materials as coatings. Low values of water vapor permeability (5.1–12.26 g/m2h) and very low transmission in the UV range (less than 2%) indicate good barrier properties. FTIR analysis confirmed the films' composite structures: peaks related to proteins, polysaccharides, lipids, and cellulose were detected. The biological activity of the obtained CSoC films was pronounced so that they could be used for active packaging. All films have high antioxidant activity, which is more pronounced in samples synthesized at pH 8. The films possess antibacterial properties against S. aureus, while some had an inhibitory effect on S. typhimurium. Standard score analysis showed that the film sample synthetized at pH = 10, temperature = 100 °C, and concentration = 5% had optimal investigated properties. [ABSTRACT FROM AUTHOR]

Food poisoning caused by Listeria monocytogenes leads to a 30% rate of mortality among patients. The application of essential oils (EOs) to food products is a suitable strategy to control pathogens and to extend their shelf life by reducing microbial levels. The objective of this study was to evaluate the antimicrobial potential of essential oils (EOs) against L. monocytogenes. The EOs used in this study were caraway (Carum carvi), cinnamon (Cinnamomum zeylanicum), dill (Anethum graveolens), clove (Syzygium aromaticum), mentha (Menthae piperitae aetheroleum), red thyme (Thymus vulgaris), rosemary (Rosmarinus officinalis), common sage (Salvia officinalis), clary sage (Salvia sclarea) and summer savory (Satureja hortensis). The minimal inhibitory concentrations (MICs) of EOs were determined using the broth microdilution method. According to the MIC values, all essential oils were effective in the inhibition of L. monocytogenes strains, with MICs varying from 256 μg/ml to 4096 μg/ml. The results showed that cinnamon EO had the highest antimicrobial activity, while dill and mentha EOs were the least effective against the L. monocytogenes. In addition, two different procedures were carried out to test the effect of antibiotics gentamycin and streptomycin against the L. monocytogenes strains, the broth microdilution method and the MIC Test Strip. Our results indicated that the reference strain L. monocytogenes ATCC 19111 was much more sensitive to antibiotics than L. monocytogenes strains isolated from meat, highlighting that gentamycin was the more effective in comparison to streptomycin.

It is known that some pathogens in feed production plants may exist throughout several months, even years. These strains are known as 'house strains' and the assumption is that the existence of such strains is enabled due to their ability to form biofilms. The objective of our experiment was to assess survivability of selected isolates that were previously characterized as rdar morphotype enclosed into biofilm on glass surfaces. Testing of cell viability in the biofilms was carried out in the condition of desiccation (28 days) and with periodic availability of nutrients (90 days) at ambient temperature. In both of tested conditions percent of viable cells was more than 50 % for all tested isolates. The obtained results suggest that survivability of Salmonella Enteritidis rdar morphotype cells enclosed into biofilm on glass surfaces under conditions of desiccation and periodic availability of nutrients may present a serious problem in the food and feed industry due to biofilm production, which contributes to their spreading throughout the whole facility and consequently increasing cross-contamination risks.

Listeria monocytogenes is ubiquitous in nature and a major concern for the food industry, since it is the causal agent of the serious foodborne illness listeriosis. This organism can be introduced through many routes to food-processing environments and may become established on food-processing equipment. Subsequently, food products may become contaminated during processing. In addition, the bacterium can grow at refrigeration temperatures. Biofilms are regarded as important with respect to the survival and growth of microorganisms in the food industry. Microorganisms growing in biofilms are protected against cleaning and disinfection and are difficult to eradicate. L. monocytogenes may grow in biofilms that protect them against environmental stress and can be isolated from surfaces after cleaning and disinfection. In this study, a total of eight L. monocytogenes strains isolated from the meat industry and one reference strain L. monocytogenes ATCC 19111 were studied for their capability to form a biofilm. The biofilm forming behavior of nine L. monocytogenes strains was determined in two different media, Tryptone soya yeast extract broth (TSYEB) or Brain-heart infusion broth (BHI), at temperatures 7 °C, 25 °C, 37 °C, 42 °C for 5 days. The method used to assess biofilm formation was crystal violet staining. All strains were able to form biofilm, but the growth condition affected the levels formed. The lowest biofilm formation was observed at 7 °C. Further, the most effective medium in promoting biofilm production by the L. monocytogenes isolates from meat was BHI medium while for reference strain L. monocytogenes ATCC 19111 it was TSYEB. Incubation temperature was the most significant factor influencing the biofilm production levels, and also the type of used nutritive medium was important factor.

Saccharomyces boulardii is unique probiotic and biotherapeutic yeast, known to survive in gastric acidity and it is not adversely affected or inhibited by antibiotics or does not alter or adversely affect the normal microbiota. S. boulardii has been utilized worldwide as a probiotic supplement to support gastrointestinal health. The multiple mechanisms of action of S. boulardii and its properties may explain its efficacy and beneficial effects in acute and chronic gastrointestinal diseases that have been confirmed by clinical trials. Caution should be taken in patients with risk factors for adverse events. Its potential application in various dairy foods could offer an alternative probiotic product to people suffering from antibiotic-associated diarrhea. This review discusses the evidence for efficacy and safety of S. boulardii as a probiotic for the prevention and therapy of gastrointestinal disorders in humans.

The use of natural antifungal agents has gained much attention to extend shelf-life, increase the safety of food products in the food industry and inhibit disease-causing microorganisms. The objective of this study was to evaluate the antifungal and anti-adhesion potential of 15 plant extract, essential oils and chemical compounds against Candida spp. and Pichia spp. Susceptibility tests indicated that essential oils of Cinnamomum verum and Origanum vulgare had the highest inhibitory effect. For most extracts and essential oils examined, Pichia membranifaciens ZIM 2417 was the most sensitive yeast, while Candida glabrata ZIM 2369 proved to be the least sensitive one. Anti-adhesion ability of the plant extracts and essential oils against C. glabrata ZIM 2369 was estimated by the standard crystal violet assay. The results showed that the essential oils of C. verum, O.vulgare, Satureja montana and Thymus vulgaris possessed promising activity against the initial phase of biofilm formation and the pre-formed 24 h biofilm of C. glabrata. On the other hand, Sedum roseum extract showed the strongest anti-adhesion effect. Results of this study support the use of plant extracts, essential oils and their biologically active components against C. glabrata. [ABSTRACT FROM AUTHOR]

Yeast adhesion to and biofilm formation on surfaces is present in many different environments. In food industry, bio films may be a source of contaminations, causing food spoilage and reducing quality of products. Candida and Pichia are two common yeast genera involved in the spoilage of some food products. The aim of this study is to assess the potential of Candida and Pichia species to adhere to two types of wooden surfaces (smooth and rough), one of the materials typical for the food processing industry, and investigate the influence of surface roughness of wood on the degree of yeast adhesion. The adhesion of the cells to the wooden surfaces was determined by rinsing them from the surface, followed by methylene blue staining, and quantification after imaging under microscope by automatic counting of viable cells. The results showed that all Candida and Pichia strains were able to adhere to the wooden surfaces in a species- and strain-dependent manner. On the other hand, our data indicated that adhesion by these yeasts was not significantly affected by the roughness of the wood surfaces. [ABSTRACT FROM AUTHOR]

The use of natural substances with antimicrobial activity in combination with conventional antimicrobial agents is a promising strategy in the control of pathogenic bacteria. The aim of this study was to examine the antimicrobial activity of a disinfectant based on sodium hypochlorite and lavender, tea tree, peppermint and rosemary essential oils against Gram-positive (Bacillus cereus ATCC 11778, Staphylococcus epidermidis ATCC 12228) and Gram-negative (Pseudomonas aeruginosa ATCC 10145, Salmonella Typhimurium ATCC 14028) bacteria. Further, to evaluate the antimicrobial activity of essential oils and the disinfectant mixed in various combinations in order to detect synergistic or antagonistic effects and discuss these effects on the basis of an improved checkerboard technique. The results showed a synergistic and additive effect for most combinations of the disinfectant and essential oils with fractional inhibitory concentrations index (FICI) values of 0.375 and 1, respectively. The effectiveness of the disinfectant in combination with essential oils was also determined using the quantitative suspension test and results indicated the maximum germicidal effect after the exposure time of 5 min. Taking into account increased interest in the use of natural antimicrobial agents in recent years, the application of a combination of disinfectant with essential oils represents a significant strategy in the control of pathogenic bacteria. [ABSTRACT FROM AUTHOR]