Culinary Treatment Research Articles

Leaching of cadmium, lead and mercury from fresh and differently preserved edible mushroom, Xerocomus badius, during soaking and boiling

Many mushroom species are known as cadmium, lead or mercury accumulators. A possibility to decrease the metal levels was therefore investigated. Leaching of the metals from fresh, freeze-dried, air-dried and frozen slices of widely consumed Xerocomus badius was tested in three experiments. Common culinary treatments, soaking in 0.3% table salt solution at ambient temperature for 5, 10 or 15 min or repeatedly for 3×5 min and boiling in the same solution for 15, 30 or 60 min, were investigated. Short-time boiling was observed as a more efficient operation than soaking. The metals were leached to the greatest extent from the most destroyed tissues of frozen mushroom slices, but less so from fresh or freeze-dried tissues. The most extensive leaching was observed for cadmium and the lowest for mercury.

Advanced Glycation End Products and Nutrition.

Advanced glycation end products (AGEs) may play an important adverse role in process of atherosclerosis, diabetes, aging and chronic renal failure. Levels of Ne-carboxymethyllysine and fluorescent AGE values were estimated in two nutritional population groups - alternative group (vegetarians - plant food, milk products, eggs) and traditional group (omnivorous subjects). Vegetarians have a significantly higher carboxymethyllysine content in plasma and fluorescent AGE values. Intake of proteins, lysine and monosaccharides as well as culinary treatment, consumption of food AGEs (mainly from technologically processed products) and the routes of Maillard reaction in organism are the substantial sources of plasma AGEs. Vegetarians consume less proteins and saccharides. Lysine intake is significantly reduced (low content in plant proteins). Subjects on alternative nutrition do not use high temperature for culinary treatment and consume low amount of technologically processed food. Fructation induced AGE fluorescence is greater as compared with that induced by glucose. It is due to higher participation of a more reactive acyclic form of fructose. Intake of vegetables and fruit with predominance of fructose is significantly higher in vegetarians. Comparison of nutrition and plasma AGEs in vegetarian and omnivorous groups shows that the higher intake of fructose in alternative nutrition of healthy subjects may cause an increase of AGE levels.

A review of trace element concentrations in edible mushrooms

Wild growing mushrooms have been a popular delicacy in many countries. Some species, mainly from genera Agaricus, Macrolepiota, Lepista and Calocybe accumulate high levels of cadmium and mercury even in unpolluted and mildly polluted areas. The concentrations of both metals and also of lead increase considerably in the heavily polluted sites, such as in the vicinity of metal smelters. The usual concentrations of the three deleterious metals are presented in tables for 25 species consumed within Europe. A brief overview of 12 other metals in mushrooms is also given. Present knowledge of metal speciation in mushrooms is limited as is knowledge of their bioavailability in man. Thus, consumption of the accumulating species should be restricted. Semimetals selenium, arsenic and antimony do not occur in undesirable levels. The cultivated species, especially the common mushroom ( Agaricus bisporus) and oyster mushroom ( Pleurotus ostreatus) contain only low levels of the trace elements. Very scarce information is available on metal losses during preservation and culinary treatment of mushrooms.

Comparison of volatile components in raw and cooked green beans by GC-MS using dynamic headspace sampling and microwave desorption

The effects of four culinary treatments (steaming and boiling in a covered pot, a pressure cooker or a microwave oven) on the volatile component profile of green beans were evaluated. Volatile compounds in raw and cooked beans were analysed by means of dynamic headspace sampling onto an adsorbent, followed by microwave desorption into a gas chromatograph equipped with a mass spectrometric detector. Twenty-seven compounds were identified, including alcohols, aldehydes, ketones, esters, terpenes, sulphur compounds and alkenes. All of the thermal treatments caused important changes in the volatile compound profile in particular an increase in carbonyl compounds and a decrease in alcohol compounds, most notably in the case of the covered pot. It is concluded that the change in aroma during the cooking of green beans depends on compounds from lipid oxidation as well as compounds from other types of reactions, for instance the Strecker degradation.

The effects of various culinary treatments on the pigment content of green beans ( Phaseolus vulgaris, L.)

The effects of four culinary treatments (steaming and boiling in a covered pot, a pressure cooker or a microwave oven) on the chlorophyll a and b, all- trans-lutein, phaeophytin a and b and all- trans- β-carotene (provitamin A) contents of green beans ( Phaseolus vulgaris, L.) were evaluated. The pigments in the fresh and treated beans were determined by gradient elution reverse-phase HPLC with UV detection. Boiling the beans in a covered pot, pressure cooking or microwaving them caused smaller losses of pigments than steamed cooking. Since pressure cooking also generally leads to smaller losses of nutritious components (e.g. vitamin C), it is recommended over the traditional method of boiling beans in a covered pot.

Pesticide Residue Concentrations in the Belgian Total Diet, 1991-1993

In the period 1991-1993, an official study was conducted to measure the presence and evaluate the risk of pesticide residues in plantbased food in the Belgian total diet. Positive samples were subjected to one or more culinary treatments (washing, peeling, steaming, or cooking) to determine the decrease of residues in prepared ready-to-eat food. Thus, better estimates of pesticide residues taken up through consumption were determined and compared with toxicological criteria. Washing did not significantly reduce residues. Peeling fruits removed almost all pesticides. The effects of cooking and steaming varied, depending on the type of food and pesticide.

Epidemiological aspects of the Bombay duck or ‘bombil’ (Harpodon nehereus buch.)

The survival of the organismsMicrococcus pyogenes var.aureus,Escherichia coli, Salmonella typhosa, Salmonella schottmuelleri andVibrio comma in sea water and in thebombil tissue has been studied. In addition the survival of these organisms in inoculated fish subsequently refrigerated, dehydrated, or held at room temperature has been studied. The effect of heat and culinary treatment on the inoculated fish has also been observed. Our results when correlated with the casual occurrence of bacteria of faecal origin on the flesh and ventriculus of the fish, together with the findings that cocci are present in large numbers on the skin and in almost pure culture in the ventriculus of the dehydrated fish (these have been reported in a previous communication, 1953), suggest the possibilities of this fish being a carrier of enteric infections. The fact thatE. coli, S. typhosa andM. pyogenes var.aureus resist culinary treatment, also indicates that infection is possible on consuming contaminated foods, even after the cooking process.