Tag Archives: stability

1232–1241 K. Sirviö, S. Niemi, S. Heikkilä and E. Hiltunen
Effects of sulphur on the storage stability of the bio and fossil fuel blends
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Effects of sulphur on the storage stability of the bio and fossil fuel blends

K. Sirviö*, S. Niemi, S. Heikkilä and E. Hiltunen

University of Vaasa, Faculty of Technology, PL 700, FIN-65101 Vaasa, Finland
*Correspondence: katriina.sirvio@uva.fi

Abstract:

In this study, the aim was to find out if mixing two common fuels together could be beneficial for both the environment and storage stability of fuel. It is obvious, that adding biodiesel to fossil fuel will decrease its sulphur content and reduce its carbon monoxide and hydrocarbon, sulphur dioxide and soot emissions. But will the high sulphur content enhance the storage stability of the biodiesel? Four B20 samples were produced, consisting of 20 vol% biodiesel and 80 vol% fossil diesel. The samples were prepared from rapeseed methyl ester (RME), low sulphuric fossil diesel fuel and high sulphuric diesel solvent. The blends had different sulphur contents of 6, 76, 149 and 226 mg kg-1. For these B20 fuel samples, the parameters were compared that correlate with the storage stability of the fuel blends. The studied parameters were the oxidation stability (OSI, according to EN 15751:2015), acid number (AN, according to EN 14104:2003) and kinematic viscosity (KV, by Stabinger SVM 3000 rotational viscometer). The measurements were carried out straight after mixing the blends, and again after 4, 8 and 12 weeks. According to the results, the fuel containing less sulphur slightly lost its oxidation stability within three months. Instead, the oxidation stability of high sulphuric samples improved within the same time frame. As a conclusion, the study gave a reason to assume that – in spite of its known drawbacks – the sulphur may be favourable to fuel blends’ storage stability but the phenomenon and chemistry should be studied in more detail.

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1002-1009 T. Michlová,, H. Dragounová and A. Hejtmánková
Stability of vitamin A and E in powdered cow’s milk in relation to different storage methods
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Stability of vitamin A and E in powdered cow’s milk in relation to different storage methods

T. Michlová¹,*, H. Dragounová² and A. Hejtmánková¹

¹Czech University of Life Sciences Prague, Faculty of Agrobiology, Food and Natural Resources, Department of Chemistry, Kamýcká 129, 165 21, Prague, Czech Republic 2Dairy Research Institute Ltd, Ke dvoru 791/12A, 160 00, Prague, Czech Republic *Correspondence: michlova@af.czu.cz

Abstract:

In this article, the influence of different ways of storage on the content of vitamin A and E in powdered cow´s milk was studied. The cow´s whole milk powder was taken directly from the manufacturer and stored for one year in 4 different ways – in the light at room temperature, in the dark at room temperature, in a refrigerator at 8°C and in a freezer at -20°C. The content of vitamins was measured 4 times during the first month and then once a month. The samples were stored for one year. Vitamins A and E were determined by HPLC using DAD and FLD detectors. Vitamin A was identified in all samples but only α-tocopherol (out of various forms of vitamin E) was detected in all samples. In all cases steeper decline of both vitamins in first 14 days of storage was identified. The highest losses of vitamin A and E in powdered milk occurred during storage in the light at room temperature. The value decreased by 91 resp. 95% of the original value.

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637-644 R. Koppel, A. Ingver
Stability and predictability of baking quality of winter wheat
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Stability and predictability of baking quality of winter wheat

R. Koppel, A. Ingver

Jõgeva Plant Breeding Institute, 1. J. Aamisepa St., Jõgeva alevik, 48306; e-mail:
Reine.Koppel@jpbi.ee

Abstract:

Baking quality of 11 winter wheat varieties was studied at the Jõgeva Plant Breeding Institute during 5 years (2005–2009). Protein content, farinograph absorption, dough stability time and loaf volume were examined in this study. The varieties were divided into clusters according to the average value of quality characteristics and coefficient of variation. Ada, Tarso, Portal, Ramiro had high protein content. Bjorke, Portal, Tarso belonged to the cluster with the highest farinograph absorption. Ada had the highest value of dough stability every year. Ada, Ebi, Compliment, Gunbo, Ramiro, Širvinta 1 and Tarso had higher loaf volume. For all the wheat quality parameters the variety effect was statistically significant but had very small magnitude compared to year effect. For the milling and baking industry, it is desirable that quality traits should be maintained as stable as possible through all environments. Varieties that had lower Cultivar Superiority value usually had higher coefficient of variation. Protein content is commonly used as predictor of baking quality. The correlation existed between protein content and farinograph absorption. Farinograph absorption correlated also with dough stability. Loaf volume had correlation with protein content only in one year out of five.

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