Showing papers in "Nahrung-food in 1994"

Rapeseed meal‐glucosinolates and their antinutritional effects Part 4. Goitrogenicity and internal organs abnormalities in animals

Abstract: This paper surveys the literature concerning biological properties of rapeseed glucosinolates, chiefly the goitrogenic activity of these compounds and their influence on the morphological and histological abnormalities of internal organs in animals. An attempt has been made to establish threshold glucosinolate levels in diet which trigger the onset or increase of internal organs impairment in animals depending on their species and breeding.

Rapeseed meal-glucosinolates and their antinutritional effects. Part 3. Animal growth and performance.

Abstract: On the basis of literature data biological properties of rapeseed glucosinolates, and especially their influence on the growth and weight of animals were characterized. The aim was to determine a limiting value of these compounds in diets for particular animal species and age groups at which no limitation of growth or development was observed. Rapssamenmehl-Glucosinolate und ihre antinutritiven Effekte. 3. Mitt. Wachstum und Leistung bei Tieren Auf der Basis von Literaturdaten sind die biologischen Eigenschaften von Rapssaat-Glucosinolaten und besonders deren Einflus auf Wachstum und Gewicht von Tieren charakterisiert worden. Ziel der Arbeit war die Bestimmung eines Grenzwertes dieser Verbindungen in der Diat besonders von Tierarten und -altersgruppen, bei dem keine Begrenzung im Wachstum und in der Entwicklung zu beobachten ist.

Winter season krill (Euphausia superba D.) as a source of n‐3 polyunsaturated fatty acids

Abstract: Krill (Euphausia superba D.) caught in winter near South Georgia were examined as a raw, intermediate product, precipitate and by product. The following assayes were performed: lipid composition (TLC), fatty acid composition (GC), lipid susceptibility to oxidation, and carotenoids content. The krill harvested in July/August was found to contain about 3% of lipids. The amount of n-3 polyunsaturated fatty acids (PUFA; eicosapentaenoic and docosahexaenoic acids) in total lipids of whole krill accounts for 19.0 ± 1.7% of fatty acids. There was no any lost of n-3 PUFA during processes used to obtain the precipitate and the lipid formula. Euphausia superba is a valuable source of n-3 PUFA, primarily because of their stability in krill.

Rapeseed meal‐glucosinolates and their antinutritional effects Part 5. Animal reproduction

Abstract: Although there is no clear evidence to fully describe the mechanism involved in glucosinolate-related effects on animal reproduction, lowered fertility in animals fed diets with rapeseed meal (RSM) inclusion is related to glucosinolate content in the diet. Negative effects can result both from multidirectional action of glucosinolates, malnutrition of mother due to the thyroid dysfunction, transfer of goitrogenic compounds to foetus and reduced transfer of nutritive compounds (e.g. iodine) through the placenta. The degree of reproduction impairment depends both on glucosinolate content and on the type of animal. Pregnant female rats are sensitive to the presence of glucosinolates, and the first symptoms of fertility impairment and lowering of offspring survival rate may occur at low glucosinolate levels, e.g. with diets containing low glucosinolate rapeseed meal (LG-RSM). In the case of swine, the limiting value above which sows fertility may be impaired is 4 mumol of total glucosinolates per g diet and 8 mmol of daily intake of these compounds. Opinions on the permitted RSM inclusion in diet for hens are very divergent. Some authors recommend limiting of the RSM inclusion to 10%, while others did not find any lowering of egg production in hens fed with two- or three-fold greater RSM inclusion rates. Most long-term experiments with heifers, cows and ewes indicate that ruminants tolerate the level of glucosinolate in LG-RSM although feeding this fodder as the only high-protein concentrate component may lead to impaired fertility.

Effect of processing on starch digestibility in some legumes — An in vitro study

Abstract: The effect of processing treatments on the rate of starch digestibility in three legumes, viz, bengal gram (Cicer arietinum L), cowpea (Vigna unguiculata) and green gram (Vigna radiata) was studied using an in vitro dialysis system The processes studied were fermentation, germination, pressure cooking and roasting The released sugars measured as glucose equivalents after 3 h digestion were expressed as digestibility index (DI) All the processing treatments except roasting, increased the rate of starch digestibility in all the three legumes Subsequent cooking of the germinated/fermented legumes lead to a further increase in starch digestibility The results of the study indicate that `slow release' property of legumes is heat labile and that loss of this property is independent of macro-nutrient and starch content

Effect of stabilization of rice bran on the extractability and recovery of proteins

Abstract: Untreated, stabilized (acid- or heat-stabilized to inactivate lipase) and parboiled rice bran samples were defatted and milled into 3 fractions of varying particle size. Proteins were extracted from the milled bran by extraction into water adjusted to pH 11.0 using 1N NaOH for 30 min. Protein content increased during milling as particle size decreased. Max. extraction of protein from defatted rice bran at pH 11.0 was 72%, of which 70% could be subsequently precipitated at isoelectric pH 4.0. Increasing extraction time or addition of NaCl, SDS, or sodium hexametaphosphate did not result in increased protein extraction. Extraction and precipitation profiles were similar for acid-stabilized and untreated rice bran and were superior to those of heat-stabilized and parboiled bran. Denaturation of protein by heat affected extractability. Protein content of concentrates obtained from unstabilized and acid-stabilized rice bran was 71-73%, compared with 39.5 and 54.5% for heat-stabilized and parboiled rice bran, respectively.

The effect of squalene on the thermostability of rapeseed oil

Abstract: The effect was studied of squalene added in the amount from 0.10 to 1.0% on the thermostability of rapeseed oil during heating at 170 °C with changes in the content of unsaturated fatty acids, polar compounds, peroxides and values of dynamic viscosity as the basis for conclusion. Under the condition applied the addition of squalene retarded the degradation of unsaturated fatty acids and limited the extend of polymerization, the most significant efficiency being achieved with the highest squalene concentration. The addition of about 0.5% of squalene was proposed as practically applicable; higher squalene concentration gave no proportional increase in its protective effect. Der Einflus von Squalen auf die Thermostabilitat von Rapsol Es wurde der Einflus eines Zusatzes von 0,10 bis 1,0% Squalen auf die Thermostabilitat von Rapsol beim Erhitzen auf 170 °C im Hinblick auf Veranderungen des Gehaltes an ungesattigten Fettsauren, polaren Verbindungen, Peroxiden und der Werte der dynamischen Viskositat untersucht, um daraus Schlusfolgerungen abzuleiten. Unter den angewendeten Bedingungen verzogerte der Zusatz von Squalen die Zersetzung von ungesattigten Fettsauren und begrenzte die Ausdehnung der Polymerisation; die signifikanteste Wirkung wurde mit dem hochsten Squalenzusatz erreicht. Ein Zusatz von etwa 0,5% Squalen wird als praktisch anwendbar vorgeschlagen; hohere Squalenkonzentrationen gaben keinen proportionalen Anstieg der Schutzwirkung.

Interactions of isothiocyanates with egg white proteins

Abstract: Glucosinolates and their very highly reactive breakdown products (mainly isothiocyanates = ITC) belong to one of the most important natural toxicants. This paper deals with the interactions of allyl-, butyl-, phenyl- and benzyl ITC with egg white proteins resulting in the formation of ITC-protein-conjugates. The ITC's react with amino groups by forming thiourea derivatives. Such reactions are well described by changes in the amounts of free amino groups and available lysine. Further reaction sites are sulphhydryl side chains of proteins leading to dithiocarbamate esters. The investigations further show that such reactions are accompanied with a decrease in the solubility of the prepared conjugates. Simultaneously a shift of the isoelectric range to a lower value of pH can also be observed. Changes in electrophoretic patterns and mobility can also be seen due to the strong electrophilic attack of ITC to proteins. Comparison of the 4 investigated preparations shows that benzyl-ITC is the most reactive partner for egg white proteins. Glucosinolate und ihre reaktiven Spaltprodukte (hauptsachlich Isothiocyanate = ITC) zahlen zu den wichtigsten naturlichen Schadstoffen. Wie gezeigt wird, fuhren Wechselwirkungen von Allyl-, Butyl-, Benzyl- und Phenyl-ITC mit Eiklarproteinen (frisches Eiklar) zur Bildung von ITC-Protein-Konjugaten. Die ITC reagieren mit Aminogruppen unter Bildung von Thioharnstoff-Derivaten. Diese Reaktionen lassen sich uber Anderungen (Abnahme) im Gehalt an freien Aminogruppen und an verfugbarem Lysin gut beschreiben. Die Sulfhydryl-Gruppen der Proteine reagieren ebenfalls mit den ITC unter Bildung von Dithiocarbamidsaureester (Nachweis uber die Schwefelkohlenstoff-Freisetzung aus diesen Estern). Infolge dieser Reaktionen wird in Abhangigkeit von Art und Menge des eingesetzten Isothiocyanates die pH-abhangige Proteinloslichkeit herabgesetzt, wobei gleichzeitig eine Verschiebung des isoelektrischen Bereiches in Richtung niedrigerer pH-Werte erfolgt. Die elektrophile Reaktion der ITC mit den Proteingruppen fuhrt weiterhin zu einer Veranderung im elektrophoretischen Verhalten (Harnstoff- und SDS-PAGE) der Proteine. Von den untersuchten Isothiocyanaten zeigt sich das Benzyl-ITC als der reaktivste Partner gegenuber Eiklarproteinen.

Chromatographic separation of flaxseed phenolics

Abstract: A column chromatography method for separation of phenolic compounds from flaxseed using Sephadex LH-20, RP-8 and silica gel is described. TLC analysis proved that separated fractions contained numerous phenolic compounds. All fractions exhibited a maximum UV absorption between 270 and 290 nm. Additional shoulders were observed between 274 and 350 nm. These results imply that lignans and their derivatives are the main phenolic compounds present in flaxseed.

Biochemical studies of some non-conventional sources of proteins. Part 7. Effect of detoxification treatments on the nutritional quality of apricot kernels.

Abstract: Detoxification of apricot kernels by soaking in distilled water and ammonium hydroxide for 30 h at 47 degrees C decreased the total protein, non-protein nitrogen, total ash, glucose, sucrose, minerals, non-essential amino acids, polar amino acids, acidic amino acids, aromatic amino acids, antinutritional factors, hydrocyanic acid, tannins and phytic acid. On the other hand, removal of toxic and bitter compounds from apricot kernels increased the relative content of crude fibre, starch, total essential amino acids. Higher in-vitro protein digestibility and biological value was also observed. Generally, the detoxified apricot kernels were nutritionally well balanced. Utilization and incorporation of detoxified apricot kernel flours in food products is completely safe from the toxicity point of view.

Biochemical and toxicological studies on the effect of high and low erucic acid rapeseed oil on rats

Abstract: Rats were fed on diets containing rapeseed oil, either containing low or high erucic acid content as well as the hydrogenated ones for 6 weeks. Body weight gain, biochemical and pathological parameters were investigated. The data showed high body weight gain for rats fed diets containing low erucic rape oil (LERo) compared with those fed either the high erucic rape oil (HERo), the hydrogenated or the partially hydrogenated oil diets. All rats showed non significant changes for total lipids, total cholesterol, GPT and GOT, except the partially hydrogenated rape oil diet which showed significant decrease for total cholesterol. Alkaline phosphatase however showed a significant decrease, while plasma phospholipids showed significant increase in rats fed on the hydrogenated oil diet. Triglycerides indicated non significant increase except in the group that received low erucic rape oil diet. Histopathological study showed changes in all tissues examined (liver and kidney). Biochemische und toxikologische Untersuchungen uber den Einflus von erucasaurereichen und -armen Rapsolen auf Ratten. Ratten erhielten 6 Wochen lang Diaten, die erucasaurearmes bzw. -reiches sowie hydriertes Rapsol enthielten. Es wurden die Gewichtszunahme verfolgt und biochemische und pathologische Parameter bestimmt. Ratten, die eine Diat mit erucasaurearmem Rapsol erhalten hatten, wiesen eine hohere Gewichtszunahme auf als solche, die Diaten mit erucasaurereichem, hydriertem oder partiell hydriertem O1 erhielten. Alle Ratten zeigten keine signifikanten Veranderungen bei den Gesamtlipiden, bei Gesamtcholesterol, GPT und GOT; lediglich bei Ratten mit der Diat mit partiell hydriertem Rapsol war eine signifikante Abnahme im Gesamtcholesterolgehalt zu verzeichnen. Bei Ratten mit der Diat mit hydriertem O1 nahm die alkalische Phosphatase signifikant ab, die Plasmaphospholipide nahmen signifikant zu. Triglyceride zeigten keinen signifikanten Anstieg; eine Ausnahme bildeten Ratten der Gruppe, die die Diat mit erucasaurearmem O1 erhalten hatte. Histopathologische Untersuchungen zeigten in allen gepruften Geweben (Leber, Niere) Veranderungen.

Flavour-enhancement of low-fat Kashkaval cheese using heat-or freeze-shocked Lactobacillus delbrueckii var. helveticus cultures

Abstract: Kashkaval cheese of different fat contents was manufactured using heat- or freeze-shocked cultures of Lactobacillus delbrueckii var. helveticus added at a level of 2% to cheese milk prior to renneting. Levels of moisture, total N, salt or titratable acidity of cheeses with different fat levels were different. Proteolysis and lipolysis in low-fat Kashkaval cheese without additives were lower than those found in full-fat cheese. Incorporation of heat- or freeze-shocked L. delbrueckii var. helveticus cultures into milk of low-fat cheese greatly enhanced proteolysis and increased slightly the levels of free fatty acids. Regular low fat cheese did not develop adequate Kashkaval cheese flavour and the cheese was firm. However, addition of heat- or freeze-shocked cultures increased the flavour intensity and improved body and texture of the resultant cheese, yielding low-fat cheese with flavour intensity and body characteristics similar to those of standard fat cheese at each stage of ripening. Aromaverbesserung von fettarmem Kashkaval Kase unter Verwendung von hitze- oder kaltegeschockten Kulturen von Lactobacillus delbrueckii var. helveticus Bei der Herstellung von Kashkaval Kase mit verschiedenen Fettgehalten werden 2% hitze- oder kaltegeschockte Kulturen von lactobacillus delbrueckii var. helveticus zur Milch vor dem Einlaben zugesetzt. Bei den Kasen mit verschiedenen Fettgehalten sind die Gehalte an Feuchtigkeit, Gesamt-N, Salz und titrierbarer Saure unterschiedlich. Proteolyse und Lipolyse sind in fettarmem Kashkaval Kase ohne Zusatze geringer als im Vollfett-Kase. Der Zusatz von hitze- oder kaltegeschockten Kulturen von L. delbrueckii var. helveticus zur Milch fur den fettarmen Kase fordert deutlich die Proteolyse und erhoht leicht den Gehalt an freien Fettsauren. Normaler fettarmer Kase entwickelt nicht das typische Kashkaval-Aroma, und der Kase ist fest. Der Zusatz von hitze- oder kaltegeschockten Kulturen erhoht jedoch die Aromaintensitat und verbessert Gefuge und Textur des resultierenden Kases. Man erhalt Kase mit Aromaintensitaten und Textureigenschaften, die dem Standard-Fettkase in jedem Stadium der Reifung sehr ahnlich sind.

Comparative studies between fumigation and irradiation of semi-dry date fruits

Abstract: This experiment was carried out on Egyptian semi-dried date fruits “El-Seidi CV.” which are used to process paste of dates. It is aimed to compare the effect of irradiation (1.5, 3.0 kGy) and fumigation with methyl bromide (MB) on physical, chemical and mycological characters, especially production of aflatoxins during storage of the dates for long time (8 months). Irradiation was more effective in de-infestation of dates than MB, but caused significant loss in weight of dates. No significant changes were observed in irradiated samples as well as in MB samples for moisture content, pH-values and titratable acidity, but significant changes were observed in browning and sugars, either total, reducing, non reducing or sugar/acid ratio. Irradiation (3.0 kGy) was more effective than other treatments for inhibition of the growth of fungi and prevention of aflatoxin production in synthetic broth media or date fruits. Therefore, irradiation dose (3.0 kGy) can be recomended to use than fumigation (MB) to keep date fruits with good quality, free from infestation, contamination and more safe for human consumption during long storage period.

Aluminium content in tea leaves and in differently prepared tea infusions

Abstract: Aluminium content of tea leaves has been engaging the attention during recent years because of its uptake in the form of beverages such as tea. Hence, data were generated on the Al content in tea and its infusions, using an inductively coupled plasma spectrometer. The average values of Al in fresh tea leaves and commercial tea powders were 250 and 325 pg/g dry wt., respectively. Tea infusions contained 20-80 pg/l of Al. Al complexes with tea components like tannic acid and theoflavins were studied and stability characteristics as well as the nature of the complexes were computed.

Importance and utilization of amaranth in food industry Part I. Characteristic of grain and average chemical constitution of whole amaranth flour

Abstract: Amaranth seeds are very small. Their bulk density is 843 g dm−3. Basic analysis of amaranth whole flour from Slovakia proved evidently a high content of proteins (17.7% on dry basis), what is typical for amaranths. The lipid content of amaranth grains is rather high (7.32% on d. b.). Amaranths with their high content of fat are similar to oats. From the point of storage time of the amaranth flour the high content of fat was assumed as an unfavourable factor. The quantity of fiber (4.91% on d.b.) is comparable with more varieties of amaranth cultivated abroad. Amaranth has a relatively high content of Ca, Mg, P, K and Fe. The quantity of thiamine corresponds to the average values of amaranth grown abroad. Riboflavin is present up to quadruple amount in comparison to the literature. The acidity of flour during 6 weeks of resting increased relatively little.

Distribution of radioactive octacosanol in response to exercise in rats

Abstract: To study the mechanism of action of octacosanol in rats the biodistribution of radioactivity of octacosanol was investigated in response to exercise. The amount of voluntary exercise was significantly higher in octacosanol fed rats than in the control. After ingestion of 14C-octacosanol, the accumulation of radioactivity of octacosanol in the muscle of exercised group given octacosanol was significantly higher in comparison with that of the exercised control group given no octacosanol and also the non-exercised groups irrespective of whether they were given octacosanol or not. The muscle thus seemed to be able to store a considerable amount of octacosanol in response to exercise. Although the exact mechanism of increase in physical exercise caused by octacosanol is not known, it is possible that octacosanol increases the mobilization of free fatty acids from fat cells within muscle. The results indicate that octacosanol possesses an adipokinetic activity, which might affect the lipolysis process of muscle.

Untersuchung über Änderungen von Fleischproteinen während der Gefrierlagerung

Abstract: Es wird der Einflus des Gefrierens und der Gefrierlagerung auf Proteine des Muskels L. dorsi vom Schwein untersucht. Frisches Fleisch wird in Scheiben (1 cm dick) geteilt, eingepackt und eingefroren (2 verschiedene Geschwindigkeiten). Nach 0 h (Kontrolle), 48 h, sowie 2, 4 und 6 Monaten Gefrierlagerung werden Proben genommen und Anderungen der Proteine mit Hilfe der DSC und der Polyacrylamid-Gelelektrophorese untersucht. Die DSC-Thermogramme zeigen 4 Peaks, von denen dem 1. Peak Myosin und dem 4. Peak Actin zugeordnet wird. Der 2. Peak wird durch sarkoplasmatische bzw. Bindegewebs-Proteine verursacht. Der 3. Peak ist nicht identifiziert. Beim Messen der Enthalpien des DSC-Thermogramms wird festgestellt, das die Enthalpie des Myosin-Peaks wahrend der Gefrierlagerung abnimmt, die Enthalpie des Actin-Peaks aber unverandert bleibt. Zu Beginn der Versuche wurde angenommen, das die SDS-PAGE eine geeignete Methode fur die Untersuchung der Proteindenaturierung sein konnte. Die Ergebnisse zeigen jedoch keine signifikanten Anderungen in den Elektropherogrammen wahrend der gesamten Gefrierlagerung. Investigation of changes in meat proteins during frozen storage. The effect of freezing and frozen storage on proteins was investigated in case of pork L. dorsi muscle. After fresh pork was sliced (1 cm thickness), wrapped and frozen (2 different velocities) samples were taken (control, 48 h-, 2, 4 and 6 month-frozen storage) and changes in proteins investigated by DSC and SDS-PAGE. DSC-thermograms show 4 peaks corresponding to myosin (peak 1) and actin (peak 4). Peak 2 reflects the sarcoplasmic proteins and connective tissue contribution. Peak 3 is not defined. When measuring the enthalpies of the DSC-thermograms, it can be observed that the enthalpy ascribed to myosin decreases during frozen storage, while the enthalpy corresponding to actin is not affected. At the beginning of our experiments SDS-PAGE was supposed to be a proper method for the investigation of protein denaturation. Our results show no significant changes in the electropherograms during the whole period of frozen storage.

Availability of calcium from kilkeerai (Amaranthus tricolor) and drumstick (Moringa oleifera) greens in weanling rats.

Abstract: The present study was undertaken to determine the extent of calcium absorption in weanling rats from two types of greens rich in oxalates. The edible portions of greens namely kilkeerai (Amaranthus tricolor) and drumstick (Moringa oleifera) were analysed for moisture, calcium and total and soluble oxalates. Three groups of 6 male weanling albino rats were fed ad libitum on milk diet and two experimental diets containing greens. Urine and faecal samples were collected for a period of 7 days after 5 days of acclimatization period and were analysed for calcium. From the values obtained percent absorption and retention of calcium were calculated. Results revealed that calcium absorption and retention from milk diet (92 and 78%, respectively) were significantly higher than greens. Average calcium absorption and retention from greens diet were 75.5 and 60%, respectively. Presence of oxalates inhibited intestinal absorption of calcium.

Mycoflora of post-harvest maize and wheat grains and the implication of their contamination by molds

Abstract: Thirteen fungi including toxigenic Aspergillus nidulans and A. clavatus were isolated from the grains. The isolated fungi grew well at 25–30 °C. A. clavatus and A. nidulans were grown in liquid maize yeast extract medium and wheat yeast extract medium. Both fungi produced amylases on the two media and on the basal medium at 30 °C. During incubation more total reducing sugars were detected in maize grains than in wheat while non-reducing sugars were detected than reducing sugars in both grains. A. clavatus showed highest amylase activities at 25–30 °C and at a pH 7–8 while 30 °C and pH 6.0 were the optimum conditions for highest amylase activities of A. nidulans. During incubation with both fungi a decrease in the protein and carbohydrate contents of both grains was recorded while more fat was accumulated in the grains. Pilzflora von Mais- und Weizenkornern nach der Ernte und Auswirkungen der Kontamination mit Pilzen Aus den Kornern werden 13 Pilze einschlieslich der toxigenen Arten Aspergillus nidulans und A. clavatus isoliert. Sie zeigen bei 25–30 °C gutes Wachstum. A. clavatus und A. nidulans werden im flussigen Mais-Hefeextrakt- und Weizen-Hefeextrakt-Medium gezuchtet. Beide Pilze bilden auf beiden Medien und auf dem Basalmedium bei 30 °C Amylasen. Wahrend der Bebrutung werden in Maiskornern mehr reduzierende Zucker als in Weizenkornern ermittelt, wogegen in beiden Kornerarten mehr nichtreduzierende als reduzierende Zucker freigesetzt werden. A. clavatus weist die hochsten Amylaseaktivitaten bei 25–30 °C und pH 7–8 auf, wahrend fur A.nidulans hierfur optimale Bedingungen bei 30 °C und pH 6,0 vorliegen. Wahrend der Bebrutung mit beiden Pilzen erfolgt eine Abnahme im Protein- und Kohlenhydratgehalt, dagegen wird Fett in den Kornern angereichert.

Mould contamination and the influence of water activity and temperature on mycotoxin production by two aspergilli in melon seed.

Abstract: Both the moisture levels and the incidence of mould contamination recorded for shelled water melon seed samples (22) obtained from 9 markets were generally higher as those recorded for the unshelled seed samples. 16 fungi, mostly toxigenic, were isolated from the surface-disinfected mouldy seeds. Of these isolates, 7, 3 and 2 species belonged to Aspergillus, Penicillum and Fusarium genera, respectively, while Botryodiplodia, Rhizopus, Sclerotium and Syncephalastrum had one respresentative each. Production of aflatoxins (B1, B2) by 5 toxigenic strains of Aspergillus flavus and of ochratoxin A by 4 toxigenic strains of A. ochraceus in melon seed at varying water activity (aw) and temperature levels were investigated. Of the aw levels (0.65, 0.70, 0.80, 0.90 and 0.98) provided, toxins were detected only at and above 0.80 with the peak production recorded at either 0.90 or 0.98 aw level. Whereas aflatoxins were produced and detected under all the test temperatures (15, 20, 25, 30, 35, and 40 °C), the elaboration of ochratoxin A was detected only as from 25 to 40 °C. Optimum temperature for toxin production by all the strains of the two fungi used was 30 °C. Pilzkontamination und der Einflus der Wasseraktivitat und der Temperatur auf die Mycotoxinbildung durch zwei Aspergilli in Melonensamen Die Wassergehalte und die Haufigkeit der Pilzkontamination waren bei geschalten, von 9 Markten erworbenen Wassermelonensamen (22 Proben) allgemein hoher als bei ungeschalten Samen. Aus den oberflachen-desinfizierten pilzhaltigen Samen wurden 16, meist toxigene Pilze isoliert. Von den Isolaten gehorten 7 zur Gattung Aspergillus, 3 zur Gattung Penicillium und 2 zur Gattung Fusarium: Botryodiplodia, Rhizopus, Sclerotium und Syncephalastrum waren je einmal vertreten. Es wurde die Bildung von Aflatoxinen (B1, B2) durch 5 toxigene Stamme von Aspergillus flavus und von Ochratoxin A durch 4 toxigene Stamme von A. ochraceus in Melonensamen bei unterschiedlicher Wasseraktivitat (aw) und unterschiedlichen Temperaturen untersucht. Bei den aw- Werten (0,65, 0,70, 0,80, 0,90 und 0,98) wurden Toxine nur bei den Werten uber 0,80 nachgewiesen; die grosten Mengen wurden bei 0,90 und 0,98 gebildet. Wahrend Aflatoxine bei allen getesteten Temperaturen (15, 20, 25, 30, 35 und 40 °C) nachgewiesen werden konnten, erfolgte die Ochratoxin A-Bildung nur bei Temperaturen zwischen 25 und 40 °C. Die optimale Temperatur fur die Toxinbildung lag fur alle Stamme der beiden Pilze bei 30 °C.

Comparison of processing treatments on the composition and functional properties of rapeseed preparations (Brassica campestris L. var. toria).

Abstract: Rapeseed preparations viz. rapeseed meal, concentrates and isolates were prepared using different processing treatments involving organic solvents, acids, alkali, steaming and boiling. Their antinutritional constituents and functional properties were studied in comparison to undefatted meal. Percent decrease in phytic acid and phenolic content was maximum in seeds boiled for 30 min and isolates, respectively. Isolate II prepared by sodium hexa-metaphosphate had minimum glucosinolates, maximum content of total proteins and much improved nitrogen solubility, emulsifying and foaming properties. Water absorption and fat absorption capacities were enhanced by boiling seeds prior to grinding and ammonia-methanol extraction, respectively. Viscosity decreased in all the treatments as compared to control. Vergleich verschiedener Verarbeitungsmethoden auf Zusammensetzung und funktionelle Eigenschaften von Rapssaatpraparaten (Brassica campestris L. var. toria) Rapssaatpraparate (Rapsmehl, Konzentrate, Isolate) wurden unter Anwendung verschiedener Methoden (organische Losungsmittel, Sauren, Alkali, Dampfbehandlung, Kochen) hergestellt. Ihre antinutritiven Bestandteile und funktionellen Eigenschaften wurden im Vergleich zu nicht entfettetem Mehl untersucht. Die prozentuale Abnahme des Gehaltes an Phytinsaure und an Phenolen war maximal bei Rapssaat, die 30 min gekocht worden war bzw. bei Isolaten. Isolat II, das unter Verwendung von Natriumhexametaphosphat hergestellt worden war, hatte ein Minimum an Glucosinolaten und einen maximalen Gehalt an Gesamtproteinen; Stickstoffloslichkeit, Emulgier- und Schaumbildungseigenschaften waren stark verbessert. Die Wasserabsorptions- und Fettabsorptionskapazitaten wurden durch Kochen der Saat vor dem Zerkleinern bzw. der Ammoniak-Methanol-Extraktion verbessert. Die Viskositat nahm gegenuber den Kontrollen bei allen Behandlungen ab.