1,720,998 research outputs found
Structural and Physico-Chemical Changes of Mozzarella di Bufala Campana Cheese Influenced by Covering Liquid Composition
No full text: Mozzarella di Bufala Campana is an Italian protected designation of origin cheese characterized by a stretched structure, high moisture (<65%), and short shelf life (<30 days). This cheese is generally stored refrigerated in a covering liquid that is an aqueous solution containing NaCl and organic acids. Although microbial growth has been reported as the main cause of quality deterioration, physico-chemical phenomena (water/solute migration, enzymatic reactions, etc.) also play a role in determining the cheese quality and its storability. This study investigates the effect of covering liquids formulated with different percentages of NaCl (1, 2%) and types of organic acids (lactic acid, citric acid, and a 1:1 mix of both) on the evolution of some physico-chemical characteristics of the cheese (moisture, pH, electrical conductivity, color, expressible serum, texture, rheology) during a 30-day storage period. Eight cheese batches collected from different dairies were considered as replicates of the study. The % of NaCl in the covering liquid showed a strong, significant effect on the evolution of different structural, physico-chemical characteristics of the cheeses; in particular, a NaCl concentration of 2% caused the greatest extent of moisture content increase because of casein swelling during storage, accompanied by softening of the structure
Differential scanning calorimetry application to freeze-dried milk and milk fractions
No full textThe thermal profiles of whole freeze-dried raw milk, obtained by differential scanning calorimetry (DSC) upon heating, were compared to those of their concentrate fractions (cream, skimmed milk, acid casein and whey) in order to associate the thermal peaks with the related components. Two peaks associated with fat melting, a glass transition attributed to caseins and a complex exothermic peak associated with lactose and its interactions with the other milk components were observed, in a close relation to the values of water activity of the samples. Freeze drying is the least invasive technique for drying milk, thus the results of this study may be attributed to the thermal transitions of milk components in their native state, unlike what is observed on roller- or spray-dried milk. The DSC technique is confirmed as an effective tool for the evaluation of the thermophysical properties of milk, as modified by different industrial processes
Influence of Different Starches on the Thermo-Rheological and Textural Properties of Plant-Based Gels
No full textExtraction of phycocyanin—A natural blue colorant from dried spirulina biomass: Influence of processing parameters and extraction techniques
No full textAbstract: Phycocyanin, a natural blue colorant, is typically extracted from liquid biomass of Arthrospira platensis, a blue–green algae called spirulina. In this study, we developed a scalable process to extract phycocyanin from dried spirulina biomass. First, we established the optimal ionic strength and pH for the extraction buffer. The results showed that a minimum ionic strength (>5 g/L NaCl) must be maintained to minimize the co-extraction of the green chlorophyll. The optimal pH of the phosphate buffer (100 mM) for phycocyanin extraction is 7.5; however, the pH should be immediately adjusted to 6.0 to 6.5 after the extraction to keep phycocyanin stable. Second, we also investigated three processing techniques, that is, high-pressure processing (HPP), pulsed electric field (PEF), and ultrasonication, to break the cell walls of spirulina and facilitate the release of phycocyanins into extraction buffers. HPP and PEF do not lead to the release of phycocyanin into the extraction buffer. However, ultrasonication breaks down the spirulina into fine particles and releases most of the phycocyanin, along with other impurities, immediately after the treatment. Last, it has been revealed that most of the phycocyanin can be extracted from biomass within 3 hr by phosphate buffer only (pH 7.5, 100 mM) at room temperature. It is concluded that there is no need to treat the rehydrated biomass solution by HPP, PEF, or ultrasonication due to the minimal benefits they brought for the extraction. Based on these results, we proposed an extraction process for the plant production of phycocyanin starting from dried spirulina biomass. Practical Applications: Limited information can be found on the extraction of phycocyanin from dried spirulina biomass, especially how to better preserve the natural blue color of phycocyanin during extraction. We have investigated the method and presented a different view from previous processes. Pulsed electric field, high-pressure processing, and ultrasonication were employed to accelerate the extraction of phycocyanin from dried biomass. However, it was found that, unlike the extraction from live wet biomass, these techniques do not help with the extraction from dried biomass. Based on investigations, we have proposed a process that can be easily scaled up for the commercial production of phycocyanin from dried spirulina biomass
Exploring Italian consumer acceptance and sensory preferences of cereal bars made by Brewery Spent Grains.
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Microencapsulated olive leaf extract enhances physicochemical stability of biscuits
Full text linkFree and microencapsulated olive leaves extracts (OLE) have been proposed as natural antioxidant to prolong the stability of biscuits, under two accelerated storage conditions, with and without UV light. The equivalent of 500 μg gallic acid/ g of dough has been selected as the sensory acceptable OLE concentration. Higher total phenol content and antioxidant activity were observed in biscuits enriched with both free (B-OLE) and microencapsulated (B-MCR) OLE, in comparison to the controls (B-C), being B-MCR less affected than B-OLE during storage. Higher oxidative stability was detected for B-MCR than B-OLE and B-C, when measured by both peroxide value and Oxitest. A general hardness decrease was observed for all the formulations during storage, being however B-MCR always harder than B-OLE and B-C, probably because of the interactions of the microsphere polymers (alginate and pectin) with water. Darker colours were measured for the enriched biscuits in comparison to the control ones, being all slightly affected during storage by water migration and lipid oxidation phenomena
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