Effect of adding fresh and freeze‐dried buckwheat sourdough on gluten‐free bread quality

This study demonstrates new possibilities in using freeze‐dried buckwheat sourdoughs in the processing of gluten‐free bread (GFB). Fresh and freeze‐dried (at temperatures of 20, 40 and 60 °C) sourdoughs were added in the amounts of 10, 20, 30 and 40% of the total flour content. Significant and beneficial changes in the quality of bread under the influence of different quantities of fresh and freeze‐dried sourdoughs additive were observed. Freeze‐dried buckwheat sourdoughs at the level of 20 and 30% gave the best baking results for GFB. pH of bread significantly changed, which had a positive effect on increasing its suitability for the storage. Buckwheat sourdough dried at 40 °C is the most highly recommended for GFB processing. Higher temperatures (60 °C) caused the least change in bread volume; however, a bitter aftertaste from burning was slightly detectable. Freeze‐dried buckwheat sourdoughs can be used directly in processing, thus eliminating the long fermentation of sourdough.     

Characteristics of tiger nut milk: effects of milling

A standard method for the extraction of tiger nut milk has been introduced. It has been shown that, although milling duration improves the yield of tiger nut milk solids and its nutrient composition, there is a quantifiable loss of nutrient in the pressing residue during milk extraction. Milling duration improved the colloidal stability of the milk against creaming during 16 h of storage. A higher milling intensity resulted in the aggregation of biological polymers which resulted in colloidal destabilisation. Milling improved the lightness and stability and reduced browning rate of the tiger nut milk during storage. This report is important for the production of tiger nut milk of consistent and comparable characteristics. Milling has been introduced as a processing method for the qualitative and quantitative modulation of the properties of tiger nut milk. It is recommended to develop further strategies to improve the colloidal stability of tiger nut milk as a beverage.     

Effect of complexation of oxidised corn starch with mineral elements on physicochemical properties

The objective of this study was to determine the effect of complexation of oxidised starch with mineral elements on its physicochemical properties. Corn starch was oxidised with sodium hypochlorite and, afterwards, modified with ions of potassium, magnesium and iron. Thus, native and modified starches were analysed for: contents of mineral elements, colour parameters (L*a*b*), water binding capacity and solubility in water at temperature of 60 and 80 °C. Thermodynamic characteristics of gelatinisation by DSC, molecular weight distribution by GPC, intrinsic viscosity and pasting properties by RVA were studied. The efficiency of incorporation of metal ions into oxidised corn starch was about 30%, 20% and 20% for potassium, magnesium and iron ions, respectively. The complexation with potassium ions caused the greatest changes in the molecular weight distribution and the intrinsic viscosity of starches and viscosity of starch pastes. Only modification of starch with iron ions affected the colour parameters of the starch. Incorporation of metal ions into starch resulted also in changes in its water binding capacity and solubility in water.     

Phenotypic and genotypic antimicrobial susceptibility pattern of Streptococcus spp. isolated from cases of clinical mastitis in dairy cattle in Poland

Mastitis of dairy cattle is one of the most frequently diagnosed diseases worldwide. The main etiological agents of mastitis are bacteria of the genus Streptococcus spp., in which several antibiotic resistance mechanisms have been identified. However, detailed studies addressing this problem have not been conducted in northeastern Poland. Therefore, the aim of our study was to analyze, on phenotypic and genotypic levels, the antibiotic resistance pattern of Streptococcus spp. isolated from clinical cases of mastitis from dairy cattle in this region of Poland. The research was conducted using 135 strains of Streptococcus (Streptococcus uberis, n = 53; Streptococcus dysgalactiae, n = 41; Streptococcus agalactiae, n = 27; other streptococci, n = 14). The investigation of the antimicrobial susceptibility to 8 active substances applied in therapy in the analyzed region, as well as a selected bacteriocin (nisin), was performed using the minimum inhibitory concentration method. The presence of selected resistance genes (n = 14) was determined via PCR. We also investigated the correlation between the presence of resistance genes and the antimicrobial susceptibility of the examined strains in vitro. The highest observed resistance of Streptococcus spp. was toward gentamicin, kanamycin, and tetracycline, whereas the highest susceptibility occurred toward penicillin, enrofloxacin, and marbofloxacin. Additionally, the tested bacteriocin showed high efficacy. The presence of 13 analyzed resistance genes was observed in the examined strains [gene mef(A) was not detected]. In most strains, at least one resistance gene, mainly responsible for resistance to tetracyclines [tet(M), tet(K), tet(L)], was observed. However, a relationship between the presence of a given resistance gene and antimicrobial susceptibility on the phenotypic level was not always observed.     

N,N,N-trimethyl chitosan as an efficient antibacterial agent for polypropylene and polylactide nonwovens

The paper presents a method of depositing N,N,N-trimethyl chitosan (TMC) layers onto polypropylene and polylactide nonwovens. A two-step modification procedure is applied: first, grafting the nonwovens with acrylic acid and next layer-by-layer deposition. Turbidimetric measurements confirm the creation of polycomplexes between grafted poly(acrylic acid) and deposited TMC. The created material structure is evaluated using gravimetric analysis, reflectance Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive spectroscopy measurements and pH-metric titration. The modified material exhibits good antibacterial properties against Gram-positive bacteria Staphylococcus aureus.     

Safety assessment and antimicrobial properties of the lactic acid bacteria strains isolated from polish raw fermented meat products

Twenty-one strains of the genus Lactobacillus and the genus Pediococcus, isolated from Polish raw fermented meat products, were examined for the potential probiotic properties: resistance to simulated gastric and intestine conditions, safety assessment, and antimicrobial properties. Strains were resistant to gastric enzymes and low pH (3–6 log CFU/mL decrease) and intestinal enzymes and bile salts (1–3 log CFU/mL decrease). Most strains were resistant to gentamycin, streptomycin, vancomycin, tetracycline, ciprofloxacin, and kanamycin. Three of them (Lb. brevis BAL1, BAL10, and KL5) produced β-glucuronidase, which excludes them from qualifying as safe. Seven strains had the ability to produce bacteriocins or bacteriocin-like substances. Overall, strains Lb. brevis SCH6, Pd. pentosaceus BAL6, and KL14 revealed selected superior characteristics (resistance to the gastrointestinal conditions, safety assessment, and antimicrobial properties) as compared to the other LAB strains investigated, which made them a viable bioprotective culture that can be inoculated in raw fermented meat products as starter cultures.