Wild edible fruits as a potential source of phytochemicals with capacity to inhibit lipid peroxidation

The edible fruits of four wild small trees or shrubs (Arbutus unedo, Crataegus monogyna, Prunus spinosa and Rubus ulmifolius) traditionally consumed in the Iberian Peninsula were studied to evaluate their potential for human nutrition, considering their content in bioactive compounds. Lipophilic phytochemicals, such as fatty acids and tocopherols, as well as some hydrophilic antioxidants, such as vitamin C (ascorbic and dehydroascorbic acids), and organic acids, were analysed. In addition, the antioxidant activity, measured as lipid peroxidation inhibition (β-carotene/linoleate and TBARS assays), was evaluated in each fruit. As far as we know, this is the first report relating to bioactive compounds in wild fruits with relation to the lipid peroxidation inhibition. Data revealed that these wild edible fruits are good sources of bioactive compounds such as ascorbic acid, tocopherols and polyunsaturated fatty acids. They could be considered as functional foods or potential sources of lipidic bioactive compounds to be included as antioxidant food ingredients or in dietary supplements, mainly Rubus ulmifolius, due to its high content in tocopherols. This study provides useful and relevant information that justify tocopherols influence in the prevention of lipid peroxidation, due to the strong correlation observed (r > 0.95) between these lipophilic bioactive compounds and the antioxidant activity.ERDF and the Spanish Ministry of Education and Science (CGL2006-09546/BOS). The authors are also grateful to Fundação para a Ciência e a Tecnologia (FCT, Portugal) and COMPETE/QREN/EU for financial support to CIMO (strategic project PEst-OE/AGR/UI0690/2011). We also thank to María Molina, Laura Aceituno, Susana González, and Manuel Pardo de Santayana for their collaboration in the gathering and preparation of the samples

The profile of tocochromanols in selected dairy products with addition of plant oils

W pracy scharakteryzowano zawartość tokochromanoli (tokoferoli -T i tokotrienoli -T3) w serach dojrzewających (30 prób) oraz w produktach seropodobnych (6 prób) z dodatkiem olejów roślinnych. Analizie poddano sery, które zakupiono w supermarketach na terenie Poznania oraz uzyskano bezpośrednio od producentów. W pracy zastosowano efektywną ekstrakcję tłuszczu metodą Rose-Gottlieba. Następnie oznaczano jakościowo i ilościowo tokochromanole za pomocą wysokosprawnej chromatografii cieczowej (HPLC). Analiza tokochromanoli w przebadanych serach wykazała zafałszowania tylko w 4 próbach, w których oznaczono wszystkie formy tokoferoli α-, β-, γ- i δ-T oraz α-, β-, γ- i δ-T3. Sery oryginalne charakteryzowała tylko obecność homologu α-T.The aim of this study was to characterize tocochromanols (tocopherols -T and tocotrienols -T3) in selected dairy products - rennet ripening cheese and cheese products with addition of plant oils. The analysis was based on 36 products bought in supermarkets in Poznan and those obtained directly from the manufacturers. The first step in this research was elaboration of the effective extraction of fats. The Rose- Gottlieb method was used. Next, the HPLC method was applied for qualitative and quantitative analyses of tocopherol homologus. Original cheese was characterized by the presence of alpha-T only. Analysis of tocochromanols in 30 cheese samples showed 4 being adulterated: all forms of tocopherols and tocotrienols ((α-, β-, γ- and δ-) were present

Applying liquid chromatography [HPLC] to study the genuineness of butter

Celem pracy była ocena masła, sprzedawanego na polskim rynku, pod względem ewentualnego fałszowania jego składu poprzez zastępowanie tłuszczu mlecznego olejami roślinnymi. Stosując chromatografię cieczową, w próbkach masła oznaczono jakościowo oraz ilościowo tokoferole (–T) i tokotrienole-(-T3), charakterystyczne dla tłuszczów roślinnych. W przebadanych, losowo zakupionych w handlu detalicznym, kostkach masła Ekstra, Śmietankowego i Osełkowego stwierdzono, że 33% przebadanych próbek było produkowanych z dodatkiem tłuszczu roślinnego, o czym świadczy obecność tokoferoli, a w szczególności tokotrienoli, które występują jedynie w tłuszczu palmowym lub kokosowym. Udział procentowy tych homologów w sumarycznej zawartości -T i T-3 kształtował się na poziomie od 40 do 82%. Taka ilość oznaczonych tokochromanoli świadczy o różnym dodatku tłuszczu roślinnego do tłuszczu mlecznego i wskazuje na obecność na polskim rynku nierzetelnych producentów, którzy deklarują tylko zawartość tłuszczu mlecznego (82 lub 73,5%) na opakowaniach masła.The objective of the analysis was to assess butter sold at the Polish market from the point of view of its composition that could potentially be adulterated by replacing milk fat with plant oils. Liquid chromatography (HPLC) was applied to qualitatively and quantitatively determine two organic compounds, appearing characteristic for plant oils: Tocopherol (-T) and tocotrienol (-T3) in the samples of butter. At the retail market, slabs of butter were randomly bought called Extra, Śmietankowe, and Osełkowe; those slabs of butter were analysed. It was found that 33% of all the butter samples analysed were manufactured with plant fat added because they contained tocopherols, and, in particular, tocotrienols, which occurred exclusively in palm or in coconut oils. The percent rate of these homologues in the total content of tocochromanols ranged from 40 to 82%. The quantity of tocochromanols identified proved that various amounts of plant oil have been added to milk fat; it also meant that there were unreliable manufacturers on the Polish market who showed solely the content of milk fat (82 or 73.5%) on the packages of their butter

Applying quantum dots to determine food components and contaminants

Kropki kwantowe (QD) są półprzewodnikowymi nanostrukturami o średnicy 1 ÷ 100 nm, zdolnymi do fotoluminescencji. W roztworach oddziaływania pomiędzy atomami na powierzchni kropki kwantowej i otaczającymi je cząsteczkami mogą w istotny sposób wpływać na fotoluminescencje QD. Właściwość ta jest podstawą wykorzystania kropek kwantowych w analityce. Często stosuje się modyfikacje kropek kwantowych poprzez powlekanie ich powierzchni związkami zdolnymi do oddziaływania z analitem. Zastosowanie kropek kwantowych umożliwia opracowania nowych, czułych, selektywnych i szybkich metod analitycznych. W pracy przedstawiono metody oznaczania sacharydów, peptydów i białek, kwasu askorbinowego, związków fenolowych oraz zanieczyszczeń żywności i substancji niepożądanych. Opisano także szereg mechanizmów oddziaływania kropek kwantowych z oznaczanymi substancjami.Quantum dots (QD) are semiconductor nanostructures of a diameter between 1 and 100 nm, capable of photoluminescence. In solutions, interactions occurring between the atoms on the surface of a quantum dot and the neighbouring molecules can significantly affect the photoluminescence of QD. Owing to this characteristic, quantum dots are utilized in analytical methods. Modified quantum dots are often used; their modification consists in coating their surface using molecules capable of interacting with an analyte. The use of quantum dots makes it possible to develop novel, sensitive, selective, and quick analytical methods. In the paper, some methods are described, which are used to determine saccharides, peptides, proteins, ascorbic acid, phenolic compounds, food contaminants, and undesirable substances. Furthermore, some mechanisms are depicted of the interaction between quantum dots and an analyte