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Current study was taken up to develop probiotic chocolate using indigenous probiotic culture L. helveticus MTCC 5463. Preliminary trials included optimization of culture inoculums and physical form (freeze-dried or frozen concentrated) of addition and finally optimized product was tested for probiotic viability, texture, and organoleptic parameters at regular intervals during storage at 10±2 °C for 30 days. Probiotic chocolates prepared via incorporation of freeze dried culture (3% w/w) had acceptable organoleptic quality and had a similar behaviour as the control chocolate during storage. However, the viability of probiotic bacteria (2.42×108 CFU g–1) was achieved only up to 15 days of storage at 10±2 °C.
Abstract
The effect of the iron precursor on the thermal decomposition of iron oxyhydroxides was studied by DSC, DTA and TG in this work. Samples were prepared from iron nitrate, iron sulfate and iron chloride and the thermal curves obtained were analyzed by specific area measurements, X-ray diffraction and Mssbauer spectroscopy. It was found that the iron oxyhydroxide precursors affect the temperatures of the hematite formation as well as the textural properties of the final hematite producing particles with different diameters as following: iron sulfate (3.3 nm)<iron nitrate (15 nm)<iron chloride (24 nm).
Abstract
The effects of heating temperature of pyrolysis and activation processes on the textural and chemical properties of the chars and activated carbons prepared from oil palm stones, an abundant palm-oil mill solid waste, were studied. For both pyrolysis and activation, relatively high temperature was essential to develop pore structures in the chars and activated carbons. However, too high temperature would cause pore narrowing and pore enlargement during pyrolysis and activation, respectively. The temperature had an insignificant effect on the inorganic components of the chars and activated carbons, but affected their surface organic functional groups significantly.
Abstract
The Sanandaj-Sirjan granitoids (SSG) in western Iran are composed mainly of granite, granodiorite and tonalite. Chemically the rocks are peraluminous and metaluminous, and show S-and I-type characteristics. The oval shape of the plutons, with large axes parallel to the Zagros main trend, along with deformational textures and structures, the existence of aluminous minerals such as andalusite, garnet and sillimanite as well as micaceous enclaves and geochemical features, all support generation of these rocks by partial melting of heterogeneous source materials in a continental collision setting, corresponding to the Zagros Orogen.
Abstract
The definition as well as prediction of rock thermal behavior seems to be a quite difficult problem significantly effected by rock composition and structure. Temperature increase causes various changes of rock material (such as decomposition, oxidation, phase and polymorphic transformation, etc.). These changes are connected to thermal expansion with following appearance of tensions and cracks in minerals and rock structure. After consequential temperature decrease, developed tensions and cracks still influence the process. This study presents the application of thermogravimetric analysis, differential thermal analysis and thermomechanical analysis in characterization of selected marble thermal behavior. The texture and morphological orientation of calcite grains for marble samples was determined by optical microscopy. FTIR spectroscopy application along with X-ray diffraction (XRD) extended data about mineralogical composition. According to optical microscopy, the calcite grains show marked morphological anisotropy in one direction for some samples. Therefore, the thermal expansion had to be measured in three different (perpendicular to each other) directions. It is evident, that the effect of temperature on the final marble properties depends not only on mineralogical composition, but also on structure, texture and morphological orientation of grains. All these facts significantly influence the interpretation of differences in various marble thermal behavior.
The total viable cell count of bacteria in vacuum-packaged chilled minced beef has been decreased equally, by approx. two log-cycles, as an effect of 1.5-2.0 kGy gamma radiation or 200-300 MPa high hydrostatic pressure (UHP) treatment for 20 min. Coliform bacteria could be eliminated to non-detectable levels by the same treatments. The shelf-life of both untreated and non-thermally pasteurised samples were limited mainly by growth of lactic acid bacteria. At about equal bactericidal effect, more drastic changes of texture and colour occurred in UHP-pasteurized minced beef samples than in the radiation-pasteurized ones. Whereas radiation pasteurisation caused minimal changes in appearance, texture and DSC-thermograms of minced beef, UHP-pasteurisation of the raw samples proved to be strongly discolouring by denaturing the muscle pigments and causing extensive denaturation of the myofibrillar proteins. The water holding capacity of irradiated samples decreased, while that of high pressure treated ones increased as compared to the untreated control. Near infrared spectrometry and electronic nose measurements gave promising results to make distinctions non-destructively on changes of various physical-chemical changes and quality parameters as a function of pasteurising treatments and/or storage.
The aim of the current paper was to elucidate the influence of temperature and time on acrylamide formation and physico-chemical characteristics of bread. Additionally, the effect of asparaginase addition to bran was evaluated. With increasing baking time and temperature, the amount of acrylamide (µg kg−1) increased. The results indicated that the acrylamide concentration in treated samples with asparaginase was significantly less than those without asparaginase treatment. Based on Pearson’ test, it was found that there was a significant correlation between baking temperature and acrylamide concentration (R=0.99, P=0.025; and R=0.98, P=0.026 for the samples prepared by baking for 2.5 min and 3 min, respectively). The firmness of bread samples increased with increasing baking temperature (P>0.05), while asparaginase addition did not significant affect the textural characteristics of the final product. Breads baked at 320 °C for 3 min were more acceptable by the sensory panel in terms of their texture and chewiness, whereas the samples baked at 370 °C for 2.5 min had the lowest score in comparison to other evaluated samples.
The comparative efficacy of 0.4% carboxymethyl cellulose (CMC) and 0.3% sodium alginate (SA) was evaluated as fat replacer in low-fat (<0.5% milk fat) mozzarella pre-cheese on the basis of physico-chemical, processing, textural, and colour profile, nutritional and sensory attributes. High-fat mozzarella cheese (prepared from milk with 6.0% fat) was taken as control (FFMC), whereas low-fat mozzarella cheese (prepared from milk with <0.5% fat) without any fat replacer (LFMC) taken as negative control. The per cent yield was lower in low fat cheese with CMC (LFMC-CMC), whereas in low fat cheese with SA (LFMC-SA) it was comparable with FFMC. The moisture and protein contents were higher (P<0.05) in low-fat mozzarella cheese (LFMC-CMC, LFMC-SA) than in FFMC. The energy content in LFMC-CMC and LFMC-SA was 44 percent lower than in FFMC. The meltability decreased, whereas melt time increased in LFMC-CMC and LFMC-SA compared to FFMC. The processing and nutritional attributes were comparable in both treatments. Hardness increased, whereas chewiness decreased in low-fat cheese. However, type of fat replacer did not affect hardness of the product. Gumminess was higher (P<0.05) in LFMC-CMC than in LFMC-SA. The sensory panellists rated LFMC-SA better for flavour and overall acceptability than LFMC-CMC. The appearance, texture, and juiciness were comparable in low-fat and high-fat mozzarella cheese. Results indicated that 0.3 per cent SA can be successfully used for processing of low-fat cheese.
Sensory and physicochemical changes of three apple cultivars (‘Golden Delicious’, ‘Idared’ and ‘Gloster’) were monitored during 14 weeks of storage at 6 °C and 70% relative humidity in three following years. The aim was to investigate physicochemical parameters that were best correlated with sensory evaluation of apples during their storage. Sensory quality was assessed using a category point scale and the sensory profile was evaluated using a graphical unstructured scale. Physicochemical changes, such as weight, soluble solids, titratable acidity, and dry matter content, were monitored. All the examined parameters changed during the observed period, with the greatest changes occurring in weight, texture, and taste. There were also differences between the tested cultivars. Statistically significant correlations between sensory and physicochemical data were observed between texture characteristics and weight changes. In case of sweet taste, only a weak correlation between the intensity of sweet flavour and soluble solid content values was found. No statistically significant correlation between the intensity of sour taste and titratable acidity was observed.
Abstract
The purified bentonite parent clay, fraction ≤; 2 mm of montmorillonite type, has been pillared by various polyhydroxy cations, Al, AlFe and AlCu, using conventional pillaring methods. The thermal behavior of PILCs was investigated by combination of X-ray diffraction (XRD), thermal analysis (DTA, TG) and low temperature N2 adsorption/desorption (LTNA). Thermal stability of Al-, AlFe- and AlCu-PILC samples was estimated after isothermal pretreatment in static air on the temperatures 300, 500, 600 and 900C. Crucial structural changes were not registered up to 600C, but the fine changes in interlayer surrounding and porous/microporous structure being obvious at lower temperatures, depending on the nature of the second pillaring ion. AlFe-PILC showed higher thermal stability of the texture, the AlCu-PILC having lower values and lower thermal stability concerning both overall texture and micropore surface and volume. Poorer thermal stability of AlCu-PILC sample at higher temperatures was confirmed, the presence of Cu in the system contributing to complete destruction of aluminum silicate structure, by 'extracting' aluminum in stabile spinel form.
