In this study the content of soluble oxalate in brews of 149 samples of black teas, as well as crushed and instant coffees was determined using oxidimetric method. It was shown that the average content of soluble oxalate reaches the highest value in instant coffees (152.19 mg in 100 cm3 of brews or 25.36 mg/g of dry mass), compared with the mean content in black teas (89.19 mg in 100 cm3 or 14.87 mg/g) and crushed coffees (47.94 mg in 100 cm3 or 7.96 mg/g).
It was also found that in sample of instant coffee, which was mixed product of natural coffee and grain cereals coffee 30:70 w/w, contained reduced concentration of soluble oxalate in comparison with crushed whole natural coffees. Higher mean content of the oxalate was determined in an instant coffee obtained by spray-drying technology, and subsequently underwent a process of agglomeration, in relation to the instant coffee products subjected to freeze-drying. However, no significant differences were shown in mean oxalate content in the analysed seven commercial brands of crushed coffees. The obtained results indicated that black teas in the form of whole leaves were characterised by a higher mean oxalate content than highly disintegrated black teas packed to the ready-to-use tea bags. The highest mean oxalate content was determined in leaf teas from Sri Lanka “Ceylon Sir Roger” (125.44 mg in 100 cm3 or 20.91 mg/g), Chinese origin tea “Yunnan” (109.35 mg in 100 cm3 or 18.23 mg/g) and Indian origin tea “Madras” (94.68 mg in 100 cm3 or 15.78 mg/g). By contrast, the Indian teas packed in tea bags presented following mean level of soluble oxalates: 33.52 mg in 100 cm3 or 11.97 mg/g (“Saga”) and 38.36 mg in 100 cm3 or 9.59 mg/g (“Lipton”).
Full text available in Polish in Adobe Acrobat format:https://www.npt.up-poznan.net/pub/art_4_42.pdf
| MLA | Sperkowska, Beata, and Grzegorz Bazylak. "Analiza zawartości szczawianów w naparach czarnych herbat i kaw dostępnych na polskim rynku." Nauka Przyr. Technol. 4.3 (2010): #42. |
| APA | Beata Sperkowska, Grzegorz Bazylak (2010). Analiza zawartości szczawianów w naparach czarnych herbat i kaw dostępnych na polskim rynku. Nauka Przyr. Technol. 4 (3), #42 |
| ISO 690 | SPERKOWSKA, Beata, BAZYLAK, Grzegorz. Analiza zawartości szczawianów w naparach czarnych herbat i kaw dostępnych na polskim rynku. Nauka Przyr. Technol., 2010, 4.3: #42. |
Beata Sperkowska
Katedra i Zakład Bromatologii
Uniwersytet Mikołaja Kopernika w Toruniu
ul. Jagiellońska 13
85-067 Bydgoszcz
Poland
e-mail: gbazylak@cm.umk.pl