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Sound absorption properties of the patented wood, lightweight stabilised blockboard
2023
Roziņš, Rihards | Brencis, Raitis | Spulle, Uldis | Spulle-Meiere, Ivanda
It is well known that wood tends to shrink and swell as the relative humidity of the air changes. There have been, and still are, attempts to make dimensionally stable wood panels such as Dendrolight®. The physical-mechanical, operational, including acoustic, properties of this material have been significantly improved compared to traditional wood-based panels. However, the production of this material requires very specific processing equipment and a large energy investment. The developers of this material in Latvia invented and patented wood, Lightweight Stabilised Blockboard (LSB). In order for this material to be used in the production of various products, it is necessary to clarify its characteristic, technological, as well as operational properties. The study gathers information about the sound absorption properties of various natural and wood materials, characteristics, and the sound absorption of the studied material at different sound frequencies. The reviewed sources of information indicate that nowadays there are still problems in sound conduction and absorption and isolation issues are being addressed in building acoustics. The production of samples and the determination of sound absorption were carried out using a developed methodology developed in accordance with regulatory requirements. The data obtained in the practical study were compared with the relevant indicators of the Dendrolight® and wood-based panels used for building structures and to determine their compliance with the requirements set forth in the standards ISO 10534-2 and ISO 11654. Research data show that LSB corresponds to E sound absorption class in some of the investigated frequencies.
显示更多 [+] 显示较少 [-]Fatty acid composition of different breed goat milk
2023
Marcinkoniene, Liga | Ciprovica, Inga
The chemical composition of goat milk, especially fatty acid profile is recently renewed due to the role of monosaturated and polyunsaturated fatty acids in human nutrition. These nutrients are important to analyse in connection with the different breeds receiving the same breeding and feed. The aim of this study was to analyse goat milk fatty acid profile in relation to different breeds. Specimens for fatty acid analyses were collected from individual animals of breeds like Latvian Native (n=5), Saanen (n=5), and crossbreeds (n=5). Bulk milk samples (n=5) were also taken for milk quality testing and fatty acid range determination. Fat content was analysed according to ISO 1211:2011 and fatty acids were measured with the chromatographic method. Protein, lactose, casein and urea concentration was analysed according to ISO 13366-2:2007 and somatic cell count to ISO 9622/IDF141:2013.The highest fat concentration was determined in crossbreed milk samples (3.81 g 100 gE−1) and the lowest (2.96g 100 gE−1) in the Latvian Native breed goat milk samples. The highest butyric acid (0.12 g 100 gE−1) and caproic acid (0.12 g 100 gE−1) concentration was established in Saanen goat milk samples. Compared to other breeds, the milk of the Latvian Native breed goats is characterised by a higher capric acid (0.20 g 100 gE−1) concentration, while a higher concentration of total unsaturated and monounsaturated fatty acids was detected in the samples of crossbreed goat milk. The average fatty acid composition of bulk milk samples was 68% for saturated fatty acids, 23% for monosaturated fatty acids and 4.3% for polyunsaturated fatty acids. In analysed goat milk samples, fatty acids showed the characteristic fatty acid profile of goat milk.
显示更多 [+] 显示较少 [-]Evaluation of fatty acid composition in amaranth pasta developed for a vegan diet
2023
Marisheva, Alla | Beitane, Ilze
Consumers’ growing demand for vegan products creates a need for new nutrient-dense products. Amaranth seeds are characterised as a nutritious product due to the content of proteins, fats, etc. Considering the high-quality fats and their amount in amaranth seeds, the aim of this study was to analyse the profile of fatty acids in amaranth pasta which was developed for a vegan diet. Seven samples: amaranth, amaranth-oat, and amaranth-buckwheat pasta in different ratios, were analysed in the study. The preparation of samples for analysis was carried out according to LVS EN ISO 6498:2012; fatty acid composition was determined using thug/MS analytic method. The highest total fat content was determined in the amaranth pasta – 5453.62 mg 100 gE−1 of product, followed by the amaranth-oat pasta (85%/15%) – 4988.14 mg 100 gE−1 of product and amaranth-oat pasta (70%/30%) – 4772.93 mg 100 gE−1 of product. In the developed pasta samples, over 70% of total fat was unsaturated fatty acids and more than one-third of total fat was PUFA. The highest PUFA/SFA ratio was determined for amaranth-oat pasta (70%/30%), amaranth-buckwheat pasta (85%/15%), and amaranth-buckwheat pasta (70%/30%). Quantitatively, the essential fatty acids were oleic acid, linoleic acid, and palmitic acid. The triterpene squalene was detected with a probability of 90% in all amaranth, amaranth-oat, and amaranth-buckwheat pasta samples. The developed pasta for a vegan diet contains good-quality fat.
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