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.

Key words:

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.

Key words:

baking quality, stability, winter wheat