Bake‐Off Technology (BOT) of Par‐Baked Burger Buns: Thermal, Microstructure, Microbial, and Quality Properties During Frozen Storage

Owing to the increasing trend of consumption of ready-to-use leafy vegetables, the necessity of determining the best conditions for their frozen storage and the considerable impact of freezing on their sensory attributes, research was carried out to determine the best freezing temperature and storage time for a mixture of Allium ampeloprasum, Lepidium sativum and Stureia hortensis. The results for freezing temperature at three different storage times showed that colour and overall acceptability at - 18 °C were always ranked first (P < 0.05), while taste at - 18 °C was ranked first on days 120 and 150. The results for frozen storage time at three different temperatures indicated that colour, taste and acceptability were not significantly different. Overall, the results of this research indicated that the sensory attributes of leafy vegetables during 180 days of frozen storage were affected mainly by freezing temperature rather than frozen storage time.

Impact of guar and xanthan gums on proofing and calorimetric parameters of frozen bread dough

In attempts to produce a low-fat cheese with a rheology and texture similar to that of a full-fat cheese, guar gum (within 0.0025–0.01%; w/v, final concentration) was added to low-fat milk. The obtained cheeses were characterised regarding their physicochemical, thermal, rheological and textural properties. Control cheeses were also produced with low and full-fat milk. The physicochemical properties of the guar gum modified cheeses were similar to those of the low-fat control. No significant differences were detected in the thermal properties (concerning the enthalpy and profile of water desorption) among all types of cheeses. The rheological behaviour of the 0.0025% modified cheese was very similar to the full-fat control. Overall, no trend was observed in the texture profile (hardness, cohesiveness, gumminess and elasticity) of the modified cheeses versus guar gum concentration, as well as in comparison with the control groups, suggesting that none of the studied polysaccharide concentrations simulated the textural functions of fat in Edam cheese.

The paper presents the results of the evaluation of the effect of additives on the rheological properties of composite flour made of wheat flour in the amount of 70% and spelt flour at 30%. As additives guar gum (0.5% by weight of flour) and xanthan gum (0.16% by weight of flour) were used. Properties of produced control dough and doughs with hydrocolloids were evaluated by means of rheological appliances by Farinograph, Extenzograph, Amylograph and Rheofermentometer. Based on the observed results it can be concluded that the addition of xanthan gum has a positive effect on increasing of farinographic water absorption capacity, extension of dough development time and dough stability and generally positively affected farinographic properties. The addition of guar gum has improved especially extensographic properties as extensographic energy and extensographic resistance. Based on amylographic evaluation of control doughs and doughs with additives it can be stated that in the dough with guar gum the amylographic maximum has slightly increased. Hydrocolloid guar gum contributed to an increased retention capacity of dough observed. Based on our measurements we can indicate that addition of guar and xanthan gum contributed to an increased rheological quality of doughs prepared with addition of flour from spelt wheat. With reference to the baking experiment it was found that the use of hydrocolloids has a positive effect on the improvement of the baking properties, in particular larger volume, specific volume, and the volume yield of the dough with the addition of guar and xanthan gum compared to the control. Our results showed that aditives significantly influenced rheological qualities of dough and a baking quality of products. These findings thus allow optimizing the recipe in order to increase the technological quality of leavened bakery products.

This study was performed to evaluate the effect of different freezing conditions and storage periods on physicochemical and microbial characteristics of garlic. Garlics were washed, dried, sliced to 0.3 cm then packed in LDPE+LLDPE film bags. They were treated with still-air freezing at -20°C (SAF20), -40°C (SAF40) and immersed-liquid freezing at -40°C (ILF40). Frozen garlics were stored under frozen storage conditions for 7 months at -20°C and quality characteristics were measured monthly during the frozen storage. Freezing rate of garlic was the fastest in ILF 40 (10 min), SAF40 (40 min) and SAF20 (1,600 min) sequentially. In ILF40, drip loss, cutting force, total aerobic bacteria count and pH were the lowest, whereas pyruvic acid and allicin content were the highest (p&lt;0.05) during frozen storage, these results were the most similar characteristics with the fresh garlic. During frozen storage, drip loss, color difference and total organic acid content were significantly fluctuated in SAF20 (p&lt;0.05), while they were not changed in ILF40. Overall, total aerobic bacteria count and pH decreased, cutting force, pyruvic acid and allicin content remained unchanged in all groups. In conclusion, the optimal freezing conditions for garlic with the least quality changes was considered to be ILF40 (immersed liquid freezing), keeping quality characteristics up to 7 months by freezing storage.

ABSTRACTMonolithic NbB2, NbB2-SiC, and NbB2-SiC-GNP samples were produced by spark plasma sintering (SPS), and the effects of additives on the mechanical and thermal properties, microstructures, and oxidation behavior of the samples were investigated. The addition of SiC up to 30 vol% decreased the Vickers hardness of the binary composites due to microcrack formation. The fracture toughness and oxidation resistance of NbB2 were improved with the incorporation of SiC. Fracture toughness was higher for all the composites in comparison to monolithic NbB2, moreover the highest value of ~5.2 MPa·m1/2 exhibited by 3 vol% GNP-containing composite. A strong interface and homogeneous distribution of GNPs enhanced the thermal transfer properties and improved the oxidation resistance of selected NbB2-SiC ceramics in oxidation studies at 1200°C. A combination of high mechanical properties, high thermal conductivity, and low mass gain was achieved for the NbB2-SiC-GNP samples with 1 and 3 vol% GNPs.

Effect of frozen storage duration on temporal dominance of sensations (TDS), chemical investigations and moisture distribution of roasted chicken wings

New experimental basis was developed and implemented to provide improvement in geothermal data reliability and extension of the geothermal data application in geophysics. A continuous thermal core logging technology was developed (2015) and applied (2015-2018) on 27 300 cores from 31 wells. Correlations between thermal and other rock properties, established from integration of thermal and standard logging data, allowed to improve standard logging data quality and estimate thermal properties from standard logging data. New optical scanning instruments provide profiling thermal properties to characterize formation heterogeneity continuously with spatial resolution up to 0.2 mm. International recommendations on rock thermal property measurements were developed. The approaches were developed to improve techniques of thermal property integration in modern hydrodynamic simulators. Techniques were elaborated to determine firstly rock matrix thermal properties and provide fast thermal property measurements on rock cuttings. Rock fracturing characterization became possible from thermal core profiling. Vast data on thermal property at elevated temperatures were obtained with the special instruments. New investigations of vertical variations in heat flow performed with the new technologies confirmed our previous data on heat flow increase with a depth by 45-120 % that requires serious corrections of the previous results and reconstruction of geothermal maps often.

Effect of ultrasound pretreated hydrocolloid batters on quality attributes of fried chicken nuggets during post-fry holding.

In this study, physicochemical and organoleptical properties of muffin cake prepared by substitution of egg white with different levels of whey protein concentrate (WPC) and different levels of guar and xanthan gums in the furmolation were evaluated.WPC at three levels ;25 , 50 and 75 % , guar gum at two levels ; 0.1 and 0.3 % , and xanthan gum at two levels ; 0.1 and 0.15 % , were considered as variable treatments . Data analysis showed that addition of WPC, significantly affected the physicohemical and sensory properties of the samples. Moreover guar and xathan gum affected all the physicochemical and sensory properties except for the after one and two days of storage, crust colour and taste. The results of this research showed that although WPC alone was not an appropriet substitution for egg white, the application of WPC at levels of 25 and 50% along with guar (0.3%) or xanthan gum (0.15%) could be an appropriate substitution for egg white while maintaining sensory properties and improving almost all of the physicohemical characteristices of muffin cakes. Key words: muffin cake; whey protein concentrate; guar gum; xanthan gum; physicochemical properties; organoleptical properties.

Mildly cooked snow crab clusters were subjected to three freezing methods (in brine, in still air, and in circulating air), two frozen storage times (72 h and 6 months), and two thawing methods (in air and in circulating water) followed by refrigerated storage. The clusters were evaluated for weight changes during freezing, frozen storage and thawing as well as for drip loss and melanosis during the refrigerated storage. Both the freezing method and the frozen storage time significantly affected the weight changes (P < 0.001) and drip loss (P < 0.015), likely due to differences in the protein denaturation and crystallization phenomena related to the rates of freezing and thawing. Freezing in brine allowed the least weight loss during the freezing process whereas freezing in circulating air followed by short frozen storage and thawing in air minimized the weight loss during the frozen storage and thawing process. The melanosis was significantly affected by both the freezing and the thawing method (P < 0.001) in the case of short frozen storage, whereas for long frozen storage, only the effect of the freezing method was significant. To minimize melanosis, the clusters should be frozen in brine and thawed in water.

Smart and biodegradable packaging is very desire combination due to the combination of two very important properties nowadays. From many biode-gradable polymers starch is the first one applied in the packaging industry. In this work, a processing and properties of biodegradable composites based on Mater-Bi modified with silver was presented. The Mater-Bi/Ag composites were prepared by melt blending and injection molding process. The morphology and dispersion of Ag particles in the polymer matrix were investigated with scanning electron microscopy (SEM). The crystallization, melting behavior and thermal properties were studied using differential scanning calorimetry (DSC). The Young’s modulus, tensile strength, elongation at break and tensile-impact strength for Mater-Bi/composites with different of silver content and pure polymer were compared. Mater-Bi composites modified with silver were found to be active against Pseudomonas aeruginosa, Escherichia coli, and Listeria monocytogenes. Selected mechanical, thermal and microbial properties were conducted. Results showed a significant improvement in mechanical and thermal properties in accordance with the addition of silver into Mater-Bi matrix. Silver easily incorporated in polymer matrix and produces homogeneous Mater-Bi/0.5Ag composite. The results have shown that obtained composite have good mechanical and thermal properties and simultaneously can inhibit growth of some pathogen bacteria.

Thermal stability of proteins in frozen and thawed freshwater prawns was measured by differential scanning calorimetry. The onset and peak melting temperatures corresponding to myosin denaturation, as well as total enthalpy of denaturation of prawn muscle, decreased after freezing–thawing treatments. There were no significant differences in the thermal properties of prawns with changes in the rate of freezing, ie blast (fast) vs still (slow) freezing. However, the thermal properties were influenced by the rate of thawing. Rapid thawing using a combination of microwave and tap water resulted in a lower (P⩽0·05) thermal stability of prawn proteins compared to slow (refrigeration) or moderately fast (tap water) thawing methods. Keeping prawn shells intact or not intact during freezing–thawing did not alter the thermal properties of the prawn proteins. © 1997 SCI.

Effect of manganese addition on thermal and electrical properties of Zr45Cu45Al10 metallic glass

ABSTRACTCross-linked polymer beads with different cross-linking agent loading were prepared by carrying out cross-linking suspension copolymerization of styrene-divinylbenzene (St- DVB) monomers using guar gum (GG) and xanthan gum (XG) from bioresources as eco-friendly suspension biopolymer stabilizers in the presence of non reactive diluents. The effects of GG and XG as suspension biostabilizers on the characteristics of the styrene copolymer beads were investigated regarding thermal properties, porosity characteristics, solvent swelling ratio, and surface morphologies using TGA, DSC, XRD, SEM, BET analyses. Spherical and regular beads with smooth surface were produced and the average particle size was in the range 170–290 μm (50–80 mesh size). The porosity characteristics of the produced beads including surface area and pore volume were in range 0.45 m2/g and 32–45 ml/g, respectively. Overall, the present article provided a novel route to prepare cross-linked polystyrene copolymer beads with tunable porosity suitable for catalyst support.