Ograniczanie wyników

Czasopisma help
Autorzy help
Lata help
Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 112

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 6 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych:  extrusion
help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 6 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
The properties oť potato starch saturated with Na, K, Ca and H cations were studied in extrudates cooked at 60°-65°-75°C, 90°-105°-120°C and 140°-155°-170°C. The morphological features of the extrudates, their specific gravity and expansion ratio as well as starch properties depended on the temperature of extrusion and type of saturating cations. The higher were the temperatures of extrusion, the higher was the solubility of the extrudates, but lower rétrogradation degree and the amount of sediment obtained from centrifuged pastes. The starches saturated with Na, K, Ca and H cations, either non-extruded or extruded at 60°-65°-75°C and 90°-105o-120°C exhibited different solubility and rétrogradation degree; the starches extruded at 140°-155o-170°C were totally soluble and their rétrogradation degree was similar. Some differences in water absorption capacity of the extruded starches saturated with different cations were observed - the extrudates of Na, K and Ca starches exhibited higher water absorption capacity than non-extruded starches, while the water absorption capacity of extruded hydrogen starch was lower than before extrusion.
Background. Lactobacillus acidophilus has become increasingly popular because of their beneficial effects on health of their host, and are called proboscis. In order to exert beneficial effects for probiotics, they must be able to tolerate the acidic conditions of the stomach environment and the bile in the small intestine. Micro- encapsulated form has received reasonable attention, since it can protect probiotic organisms against an unfavourable environment, and to allow their release in a viable and metabolically active state in the intestine. The aim of this study was to investigate some factores, such as chitosan solution pH and concentration, xanthan concentration, cell suspension-xanthan ratio, mixed bacteria glue liquid-chitosan ratio, which impacted the process of microencapsulation of L. acidophilus. Material and methods. In this study, L. acidophilus was immobilized with xanthanthitosan gel using extrusion method. The viable counts and encapsulation yield of L. acidophilus encapsulated in different chitosan solution pH (4.5, 5, 5.5 and 6), in different chitosan concentration (0.5%, 0.7%, 0.9% and 1.1%), in different xanthan concentration (0.5%, 0.7%, 0.9% and 1.1%), in different cell suspension-xanthan ratios (1:5, 1:10, 1:15 and 1:20), in different mixed bacteria glue liquid-chitosan ratios (1:3,1:4,1:5 and 1:6), have been investigated by single factor experiment method. Results. The optimum conditions of microencapsulated L. acidophilus have been observed. The optimum chitosan solution pH for L. acidophilus was 5.5; the optimum chitosan concentration was 0.9%; the optimum xanthan concentration was 0.7%; the optimum cell suspension-xanthan ratio was 1:10; the optimum mixed bacteria glue liquid-chitosan ratio was 1:3. Conclusions. These results will be helpful to further optimize the process of L. acidophilus microencapsulation, and provide reference for obtaining higher viable counts and entrapped yield of L. acidophilus microcapsules.
Background. Polyphenols which are included in a group of food antioxidants have a beneficial impact on human organism, as they prevent the occurrence of life style diseases, including cardiovascular diseases and cancer. Cereals are the main source of polyphenols in a human diet, and especially rye is characterized by high level of these compounds. Many technological processes applied in food production cause a decrease of polyphenols in rye and reduce their antioxidative activity. The aim of the study was to estimate quantitative changes of polyphenols in rye grains subjected to extrusion, under varying process conditions and establish the antioxidant activity of the obtained rye extrudates. Material and methods. The materials were extrudates prepared from grains of three rye cultivars, namely Amilo, Rostockie and Agrikolo. Extrusion was performed in a single- screw laboratory extruder Brabender 20 DN. Contents of phenolic acids and apigenin in analysed samples was checked by HPLC. Antioxidant activity was measured by FRAP and EPR methods. Results. All rye extrudates contained ferulic acid levels (53-104 mg/100 g d.m.) approximately 112-316% higher as compared to raw material (25 mg/100 g d.m.). The highest antioxidant activity (using of FRAP method) was measured in extrudates prepared at extrusion parameters: 14% moisture of raw material and 180°C but the lowest at 20% moisture and 120°C. The analysis of spin label reduction kinetics (in EPR method) allowed to conclude, that its reduction was greater for extrudates (except extrudates obtained at moisture content 20% and 120°C) as compared to raw material. Conclusions. Content of polyphenols and antioxidative activity of rye extrudates is highly dependant on the moisture content of raw material and extrusion temperature.
The paper deals with the study results upon the extrusion of fine ground vegetable-herbal mixtures. The extrusion process was carried out using single-screw extruder S-60 at temperatures: section I – 70°C, section II – 100°C, and head 100°C equipped with a nozzle with 4-milimeter-diameter perforation. Before extrusion, mixtures were wetted to adjust moisture content of 10% and 30%, respectively. The achieved product did not have great water stability, thus it may be easily dissolved in water and may be applied as an additive, spice or a concentrating agent for food. High kinetic durability along with low final moisture content allows for a safe transport and storage of the product.
Processes of compaction of granular materials were described using selected models. The analysis of their accuracy on the example of wheat was the basis for the discussion on their applicability to the processing of plant-origin materials. Parameters of the model equations for wheat, compressed at 10-18% moisture content were calculated, and the relations between these parameters and wheat moisture were determined. It was found that the analyzed models described the pressure compaction of granular plant material with different accuracy, and were highly dependent on moisture. The study also indicated that the model of Ferrero et al. fits the experimental results well. The parameters of this model reflected very well the physical phenomena which occur during compression.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 6 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.