Cadmium contents of oats (Avena sativa L.) in official variety,organic cultivation,and nitrogen fertilization trials during 1997-1999

The cadmium (Cd) contents of oats (Avena sativa L.) in Finland were examined over a 3 year period in three types of trials: official variety, organic vs conventional cultivation, and nitrogen fertilization trials. Large seasonal and regional variations were found in the Cd concentrations. In official variety trials, the mean Cd contents in 1997, 1998, and 1999 were 0.046, 0.029, and 0.052 mg kg(-1) dry weight (dw), respectively, ranging from 0.008 to 0.120 mg kg(-1) dw. The concentrations were generally well below the maximum permitted level of 0.100 mg kg(-1) fresh weight. No significant differences were found between the organic and the conventional cultivation techniques. Nitrogen (N) fertilization increased the Cd contents of oats especially at high nitrogen rates (160 kg N hectare(-1) (ha)). Significant cultivar differences (p < 0.001) were determined in all trials. Cultivars Salo and Kolbu had consistently higher contents, and Belinda and Roope had lower Cd contents among the different growing conditions. Hence, it is possible to cultivate and develop oat cultivars less likely to accumulate Cd.     

Fermentation-induced changes in the nutritional value of native or germinated rye

Processing is important both for the sensory and nutritional quality of grains. In the case of whole grains, it especially may influence the levels and bioavailability of the bioactive compounds. Yeast, lactic acid and mixed fermentation were shown to vary in their effects on native and germinated wholemeal rye flour. The presence of Saccharomyces cerevisiae was important for enhanced levels of the analysed compounds. The levels of folates, free phenolic acids, total phenolic compounds, lignans and alkylresorcinols were increased especially by fermentation of germinated rye, which also resulted in lower pH when compared with native rye flour, the level of folate was increased up to seven-fold and that of free phenolic acids by up to ten-fold after germination and fermentation. Tailored fermentation thus offers a tool to further increase the bioactive potential of wholemeal rye.     

Quantities of phenolic compounds and their impacts on the perceived flavour attributes of rye grain

The use of whole grain rye products, beneficial to one's health, could be substantially extended if the typical intensively bitter flavour of rye could be modified without losing the characteristic rye-like flavour. The aim of the study was to evaluate the contribution of non-volatile phenolic compounds on the perceived flavour. Rye grain was milled into five milling fractions. The levels of phenolic compounds, i.e. the phenolic acids, alkylresorcinols and lignans, of the fractions were analysed and related statistically to sensory flavour profiles by partial least-squares (PLS) regression. The non-bound (free) phenolic acids are suggested to be most flavour-active. Cereal and intense flavour and aftertaste were related to vanillic and veratric acids, alkylresorcinol C_23:0, and other lignans except for pinoresinol. The perceived bitterness of the bran fractions was suggested to result from pinoresinol and syringic acid. Sinapic and ferulic acids, alkylresorcinols, except for alkylresorcinol C_23:0, and syringaresinol seemed to cause the germ-like flavour. Phenolic acids, alkylresorcinols and lignans distributed with a similar pattern in the rye grain as the flavour attributes: the phenolic compounds were clearly located in the outer bran fractions being intense in flavour, but not in the mild-tasting inner layers of the grain.     

Contents of vitamins, mineral elements, and some phenolic compounds in cultivated mushrooms

The aim of the study was to determine the contents of mineral elements (Ca, K, Mg, Na, P, Cu, Fe, Mn, Cd, Pb, and Se), vitamins (B(1), B(2), B(12), C, D, folates, and niacin), and certain phenolic compounds (flavonoids, lignans, and phenolic acids) in the cultivated mushrooms Agaricus bisporus/white, Agaricus bisporus/brown, Lentinus edodes, and Pleurotus ostreatus. Selenium, toxic heavy metals (Cd, Pb), and other mineral elements were analyzed by ETAAS, ICP-MS, and ICP methods, respectively; vitamins were detected by microbiological methods (folates, niacin, and vitamin B(12)) or HPLC methods (other vitamins), and phenolic compounds were analyzed by HPLC (flavonoids) or GC--MS methods (lignans and phenolic acids). Cultivated mushrooms were found to be good sources of vitamin B(2), niacin, and folates, with contents varying in the ranges 1.8--5.1, 31--65, and 0.30--0.64 mg/100 g dry weight (dw), respectively. Compared with vegetables, mushrooms proved to be a good source of many mineral elements, e.g., the contents of K, P, Zn, and Cu varied in the ranges 26.7--47.3 g/kg, 8.7--13.9 g/kg, 47--92 mg/kg, and 5.2--35 mg/kg dw, respectively. A. bisporus/brown contained large amounts of Se (3.2 mg/kg dw) and the levels of Cd were quite high in L. edodes (1.2 mg/kg dw). No flavonoids or lignans were found in the mushrooms analyzed. In addition, the phenolic acid contents were very low.     

Contents of phenolic acids, alkyl- and alkenylresorcinols, and avenanthramides in commercial grain products

The contents of free and total phenolic acids and alk(en)ylresorcinols were analyzed in commercial products of eight grains: oat (Avena sativa), wheat (Triticum spp.), rye (Secale cerale), barley (Hordeum vulgare), buckwheat (Fagopyrum esculentum), millet (Panicum miliaceum), rice (Oryza sativa), and corn (Zea mays). Avenanthramides were determined in three oat products. Free phenolic acids, alk(en)ylresorcinols, and avenanthramides were extracted with methanolic acetic acid, 100% methanol, and 80% methanol, respectively, and quantified by HPLC. The contents of total phenolic acids were quantified by HPLC analysis after alkaline and acid hydrolyses. The highest contents of total phenolic acids were in brans of wheat (4527 mg/kg) and rye (4190 mg/kg) and in whole-grain flours of these grains (1342 and 1366 mg/kg, respectively). In other products, the contents varied from 111 mg/kg (white wheat bread) to 765 mg/kg (whole-grain rye bread). Common phenolic acids found in the grain products were ferulic acid (most abundant), ferulic acid dehydrodimers, sinapic acid, and p-coumaric acid. The grain products were found to contain either none or only low amounts of free phenolic acids. The content of avenanthramides in oat flakes (26-27 mg/kg) was about double that found in oat bran (13 mg/kg). The highest contents of alk(en)ylresorcinols were observed in brans of rye (4108 mg/kg) and wheat (3225 mg/kg). In addition, whole-grain rye products (rye bread, rye flour, and whole-wheat flour) contained considerable levels of alk(en)ylresorcinols (524, 927, and 759 mg/kg, respectively).     

Nutritional Value of Commercial Protein-Rich Plant Products

The goal of this work was to analyze nutritional value of various minimally processed commercial products of plant protein sources such as faba bean (Vicia faba), lupin (Lupinus angustifolius), rapeseed press cake (Brassica rapa/napus subsp. Oleifera), flaxseed (Linum usitatissimum), oil hemp seed (Cannabis sativa), buckwheat (Fagopyrum esculentum), and quinoa (Chenopodium quinoa). Basic composition and various nutritional components like amino acids, sugars, minerals, and dietary fiber were determined. Nearly all the samples studied could be considered as good sources of essential amino acids, minerals and dietary fiber. The highest content of crude protein (over 30 g/100 g DW) was found in faba bean, blue lupin and rapeseed press cake. The total amount of essential amino acids (EAA) ranged from 25.8 g/16 g N in oil hemp hulls to 41.5 g/16 g N in pearled quinoa. All the samples studied have a nutritionally favorable composition with significant health benefit potential. Processing (dehulling or pearling) affected greatly to the contents of analyzed nutrients.     

Plant-derived biomolecules in fermented cabbage

The formation of plant-derived biomolecules during sauerkraut fermentation was studied. Cabbage was fermented with a starter culture, and the results were compared to the results of spontaneous fermentation. The concentration of flavonoids and glucosinolates was analyzed by HPLC, and that of the glucosinolate breakdown products, by GC-MS. Of the 20 different flavonoids tested, only kaempferol was found (0.9 mg/ kg FW, fresh weight). The content of kaempferol remained constant in the cabbage fiber matrix over the fermentation process. The nitrite concentration was below the detection limit in both fermentations. The total glucosinolate content in the raw material was 3.71 micro mol/g DW, dry weight. Glucosinolates were totally decomposed in both fermentations during two weeks, and different types of breakdown products were formed. Isothiocyanates, indole-3-carbinol, goitrin, allyl cyanide, and nitriles were determined in the fermented cabbage. Isothiocyanates and allyl cyanide were the predominant breakdown products in both fermentations. Sulforaphane nitrile and goitrin were found only in small quantities in the end products.     

Effect of processing and storage on the stability of flaxseed lignan added to bakery products

The study focused on the effects of processing and storage on the stability of flaxseed-derived secoisolariciresinol diglucoside (SDG) added to various bakery products. The SDG concentration of doughs, baked rye breads, graham buns, and muffins was analyzed by high-performance liquid chromatography-diode array detection; the baked products were analyzed immediately after baking and upon storage at room temperature for 1 week and at -25 degrees C for 1 and 2 months, respectively. Added SDG was found to withstand normal baking temperatures in all bakery products. SDG also was a relatively stable compound during storage. Similarly, the content of SDG in flax buns containing fat-free flaxseed meal was unaffected by storage. We conclude that cereal-based bakery products can be supplemented with flaxseed-derived SDG.     

Effect of processing and storage on the stability of flaxseed lignan added to dairy products

This study investigated the effects of processing and storage on the stability of purified, flaxseed-derived secoisolariciresinol diglucoside (SDG) added to milk prior to the manufacture of different dairy products. We analyzed the effect of high-temperature pasteurization, fermentation, and milk renneting as well as storage on the stability of SDG added to milk, yogurt, and cheese. Also, the stability of SDG in whey-based drinks was studied. Added SDG was found to withstand the studied processes well. In edam cheese manufacture, most of the added SDG was retained in the whey fraction and 6% was found in the cheese curd. SDG was also relatively stable in edam cheese during ripening of 6 weeks at 9 degrees C and in yogurt during storage of 21 days at 4 degrees C. Up to 25% of added SDG was lost in whey-based drinks during storage of 6 months at 8 degrees C. We conclude that SDG can be successfully supplemented in dairy-based products.