The effect of dietary CLA supplementation on meat and eating quality, and the histochemical profile of the m. longissimus dorsi from stress susceptible fatteners slaughtered at heavier weights

The influence of adding 2% CLA to the morning feed of a group of 20 crossbred fatteners from 70 to 130 kg on meat quality, eating quality and dietetic value of m. longissimus dorsi was evaluated compared with a group of 20 controls. Addition of 2% CLA in feed did not influence fattening and slaughter results and also some traits of meat and eating quality. The only significant differences were observed in dry matter content, in meat flavour and L^*, b^*, and hue angle value. Meat from fatteners from the experimental group had a statistically significant higher content of CLA (P0.01) and lower content of unsaturated fatty acids especially C18: 2, C18: 1 and C20: 4, PUFA fatty acids (P0.01) and a reduction in the ratio of n-6: n-3 PUFA (P0.01). No statistically significant influence of CLA on the content of cholesterol was observed. The results of the current histochemical study showed that dietary CLA supplementation significantly increased both the number and diameter of white fibres, and correspondingly reduced the number and diameter of red fibres. The percentage and diameter of intermediate fibres was unaffected by CLA.     

Antioxidative capacity of tomato products

The antioxidative capacity of methanol/water and hexane extracts of five tomato juices, four canned tomatoes and four tomato pastes was measured using two test systems: with 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS⁺) and with linoleic acid emulsion. In both the ABTS assay and the linoleic acid system, most of the antioxidative capacity of analysed products was from the methanol-water fraction, which contained polyphenols and ascorbic acid. On the basis of the wet weight of the tomato products, tomato pastes had the highest activity towards ABTS⁺ (micromoles of Trolox equivalents per gram) followed by tomato juices, and canned tomatoes. The inhibition of formation of thiobarbituric acid-reactive substances in the linoleic acid emulsion was strongly dependent on antioxidant concentration. The results suggest that tomato products, in addition to fresh tomatoes, may also be important in supplying dietary antioxidant, especially polyphenols and carotenoids.     

New or lesser known cultivar selection as a tool for sensory and nutritional value enhancement of osmo-convectively dried sour cherries

Taking into consideration the economic importance of sour cherry growing in Europe as well as the arising perspective of novel sour cherry product development, an investigation outlining the processing usefulness of some promising sour cherry cultivars that could lead to a better final product quality was undertaken. Nine new or lesser popular cultivars of sour cherries were compared to ‘English Morello’ with particular consideration given to processing suitability for osmo-convective drying. The quality of raw material was characterized taking into account fruit size, soluble solids content, acidity and pro-health properties. To assess the quality trait stability of individual cultivars, standard deviations were calculated. As a measure of ascertaining the fruits' suitability for drying, the sensory properties of osmo-dried products produced by the examined cultivars were considered. The gathered data demonstrates high seasonal variations in quality traits of the most investigated cultivars, which could well restrict their processing usefulness, especially for osmo-drying, as this product was found highly sensitive to fluctuation of raw material uniformity. Among the tested cultivars ‘Nefris’ emerged the most suitable for processing purposes. Fruits of this cultivar gave high quality dried product of repeatable sensory attributes characterized by significantly better pro-health properties than that of ‘English Morello’.     

Effect of probiotic cultures on the stability of anthocyanins in blueberry yoghurts

Dependent on anthocyanin pigments, colour is one of the main quality factors of berry products. In this paper we assess the influence of probiotic bacteria on the degradation rate of anthocyanins in yoghurts with a highbush blueberry preparation during storage. Four types of yoghurts were prepared: first with the yoghurt starter culture YC-X16 only (Steptococcus thermophilus and Lactobacilllus delbrueckii subsp. bulgaricus) and three more, each with the starter culture YC-X16 and one of the three probiotic cultures: Bb-12, La-5 and LCP, respectively (Bif. animalis subsp. lactis – Bb-12; Lactobacillus. acidophilus – La-5 and Lactobacillus. paracasei subsp. paracasei – LCP).Derivatives of malvidin were the predominant anthocyanins in the tested yoghurts. Degradation of pigments occurred in accordance with the first-order reaction and its half-life time depended on the bacterial cultures. Anthocyanins in the probiotic yoghurt made with LCP culture were characterized by lower stability than those made with the other bacterial cultures. The impact of lactic bacteria or their metabolic products on the stability of anthocyanins in berry yoghurts shows that an appropriate selection of culture for production of yoghurt is recommended.     

Physicochemical properties of starches obtained from Polish potato cultivars

Selected physicochemical, thermal, and rheological properties of starches isolated from new Polish potato varieties were determined. The starches contained 25.7–30.0 g/100 g d.m. of amylose and 59.5–90.2 mg/100 g d.m. of phosphorus. Gelatinization temperatures were 62.6–64.0, 68.9–69.9, and 73.6–77.0°C for T_O, T_P, and T_E, respectively, whilst enthalpy of gelatinization amounted to 11.1–15.3 J/g. The retrogradation degree of starch was from 52.90 to 78.53%. Pasting curves showed significant differences between the starches. Peak viscosity and final viscosity ranges were 2035–4458 and 1931–2985 mPa · s, respectively. Starch pastes exhibited non‐Newtonian, shear thinning, and thixotropic behavior. After cooling they demonstrated diversified viscoelastic properties, however, all of them were classified as weak gels. Significant linear correlations among selected rheological parameters and amylose and phosphorus content were found. Results of principal component analysis demonstrated an ability to differentiate the starches isolated from different potato varieties.     

Biodenitrification of concentrated red beet juice

The aim of the study was to determine the possibility to microbiologically remove nitrates from a concentrated red beet juice (3600?mOsm/kg) using halophilic bacteria, Halobacterium mediteranei, Halobacterium denitrificans, and Micrococcus halobius. As a result of microbiologic denitrification, dry matter content in the beet juice concentrate was reduced about 10?% and pH was found to decrease from 7.0 to 6.2. The content of nitrates in the concentrate decreased from 20 to 37?%, but in the diluted concentrate, the reduction rate of nitrates was higher, from 32 to 75?%. The highest denitrification rate was recorded for bacteria Micrococcus halobius. As a result of the fermentation process, changes in colour and contents of betalain pigments were observed. The content of betacyanin pigments decreased, while that of betaxanthin pigments increased.     

New contact acoustic emission detector for texture evaluation of apples

A new contact acoustic emission detector (CAED) was developed for the instrumental texture evaluation of apples. The goal of this work was to determine the relations between instrumental parameters and sensory texture attributes, and to develop calibration models for prediction of the sensory texture of apples with CAED. Seven apple cultivars were used for the construction and validation of the models. CAED is particularly useful for evaluation of sensory crispness, crunchiness and hardness. There is also a significant correlation of acoustic emission counts with juiciness, mealiness and overall texture. Validation of the models indicates better prediction of these sensory attributes by total acoustic emission counts than prediction by puncture firmness in terms of variance explained, root-mean-square of a model prediction, and bias.     

Antimicrobial susceptibilities of Listeria monocytogenes strains isolated from food and food processing environment in Poland

A total of 471 Listeria monocytogenes isolates from different types of food and food-related sources in Poland during 2004-2010 were examined. This number includes 200 isolates from fish, 144 from fresh and frozen vegetables, 43 ready-to-eat products (deli foods, cold cuts), 13 from dairy products, 16 from raw meats, 15 from confectionery products and 40 directly from processing plants. All isolates were subjected to serotyping and lineage assays using PCR, and antimicrobial susceptibility using E-test and a broth microdilution method. Of all isolates, 256 (54.4%), 120 (25.5%), 59 (12.5%), 36 (7.6%) were identified as serotypes 1/2a (or 3a), 1/2c (or 3c), 1/2b (or 3b or 7), and 4b (or 4d or 4e), respectively. A direct correlation between the most common serotypes and three L. monocytogenes lineages was also observed. All L. monocytogenes isolates belonged to lineages I (20.2%) and II (79.8%). All strains were sensitive to ampicillin, amoxicillin, gentamicin, erythromycin, trimethoprim, rifampicin, vancomycin, chloramphenicol and sulfamethoxazol. Two of the L. monocytogenes strains (0.42%) showed phenotypic resistance. One strain was resistant to tetracycline and minocycline due to the presence of tet(M). It did not carry gene int, which may indicate that the tet(M) gene in this strain was not integrated in the transposon Tn916-Tn1545 family. The resistance of the second strain to ciprofloxacin and norfloxacin was attributed to active efflux associated with overexpression of gene lde. Our data indicate the low prevalence of antimicrobial resistance among L. monocytogenes isolates from food and food-related sources in Poland.     

Implementation of chemometrics in quality evaluation of food and beverages

Conventional methods for food quality evaluation based on chemical or microbiological analysis followed by traditional univariate statistics such as ANOVA are considered insufficient for some purposes. More sophisticated instrumental methods including spectroscopy and chromatography, in combination with multivariate analysis—chemometrics, can be used to determine food authenticity, identify adulterations or mislabeling and determine food safety. The purpose of this review is to present the current state of knowledge on the use of chemometric tools for evaluating quality of food products of animal and plant origin and beverages. The article describes applications of several multivariate techniques in food and beverages research, showing their role in adulteration detection, authentication, quality control, differentiation of samples and comparing their classification and prediction ability.     

Comparison of Physicochemical,Mechanical, and (Micro-)Biological Properties of Sintered Scaffolds Based on Natural- and Synthetic Hydroxyapatite Supplemented with Selected Dopants

The specific combinations of materials and dopants presented in this work have not been previously described. The main goal of the presented work was to prepare and compare the different properties of newly developed composite materials manufactured by sintering. The synthetic- (SHAP) or natural- (NHAP) hydroxyapatite serves as a matrix and was doped with: (i) organic: multiwalled carbon nanotubes (MWCNT), fullerenes C60, (ii) inorganic: Cu nanowires. Research undertaken was aimed at seeking novel candidates for bone replacement biomaterials based on hydroxyapatite—the main inorganic component of bone, because bone reconstructive surgery is currently mostly carried out with the use of autografts; titanium or other non-hydroxyapatite -based materials. The physicomechanical properties of the developed biomaterials were tested by Scanning Electron Microscopy (SEM), Dielectric Spectroscopy (BSD), Nuclear Magnetic Resonance (NMR), and Differential Scanning Calorimetry (DSC), as well as microhardness using Vickers method. The results showed that despite obtaining porous sinters. The highest microhardness was achieved for composite materials based on NHAP. Based on NMR spectroscopy, residue organic substances could be observed in NHAP composites, probably due to the organic structures that make up the tooth. Microbiology investigations showed that the selected samples exhibit bacteriostatic properties against Gram-positive reference bacterial strain S. epidermidis (ATCC 12228); however, the property was much less pronounced against Gram-negative reference strain E. coli (ATCC 25922). Both NHAP and SHAP, as well as their doped derivates, displayed in good general compatibility, with the exception of Cu-nanowire doped derivates.