摘要:

AbstractThe demands concerning microbial inhibitor tests were subjected to marked changes during the last decades: It started with the claim of being able to detect contaminated milk which might cause problems during fermentation processes (‘technological safety’). Due to the present day attention drawn to toxic and allergic hazards for numerous antimicrobials Maximum Residue Limits (MRLs) or safe/tolerance levels are fixed (‘toxicological safety’). This means a variety of demands underlying permanent changes with respect to the ‘detection pattern’ which cannot be fulfilled by a single test. Within an Integrated Dectection System microbial inhibitor tests play an important role as screening methods for those antimicrobials which can be detected with satisfactory sensitivities. This paper deals with some features of microbial inhibitor tests such as detection limits, performance, susceptibility for interference factors, qualitative determination and stan

ISSN:0027-769X    

DOI:10.1002/food.19960400102

出版商:WILEY‐VCH Verlag GmbH    

年代:1996

数据来源: WILEY

摘要:

AbstractIm Verlauf der Plasteinreaktion konzentrieren sich hydrophobe Peptide überwiegend in den Aggregaten (Plasteinen), während hydrophile Peptide in Lösung (Überstand) verbleiben. Liquidchromatographische und sequenzanalytische Untersuchungen der pankreatischen Casein‐Plasteine haben ergeben, daß die Aggregate überwiegend aus den freien Aminosäuren Tyrosin, Phenylalanin und Tryptophan bestehen. Darüber hinaus enthalten die Plasteine kurzkettige Peptide insbesondere vom C‐terminalen Ende des β‐Caseins. Die Charakterisierung der funktionellen Eigenschaften der Plasteine hat deutlich gemacht, daß die Aggregation der kurzkettigen Peptide und freien Aminosäuren auf nicht‐kovalenten, hydrophoben und ionogenen Wechselwirkungen beruht. In den Überständen aus der Plasteinreaktion konnten Caseinophosphopeptidsequenzen insbesondere aus αs

ISSN:0027-769X    

DOI:10.1002/food.19960400103

出版商:WILEY‐VCH Verlag GmbH    

年代:1996

数据来源: WILEY

摘要:

AbstractThe influence of acetylation on surface adsorption and emulsifying properties of faba beans protein isolates (FBPI) was studied. Generally, acetylation improved the interfacial activity of FBPI. The plateau value of the Gibbs' adsorption isotherms measured with the Wilhelmy‐plate was between 22.97 and 24.22 mN/m. The critical association concentration (CAC), i.e. the inflection point of the adsorption isotherms, was shifted from 2.06. 10−5to 5.35. 10−7g/ml with progressive acetylation. The dependence of the CAC on the degree of acetylation was found to be significant. For FBPI stabilized n‐decane/water emulsions with varying volume fraction of oil (ϕ) the emulsifying activity index increased from 166 to 593 m2/g whereas the droplet size decreased from 7.79 to 3.4 μm with acetylation. The correlation between emulsifying activity of FBPI and both degree of acetylation and adsorption behaviour was only significant for emulsions w

ISSN:0027-769X    

DOI:10.1002/food.19960400104

出版商:WILEY‐VCH Verlag GmbH    

年代:1996

数据来源: WILEY

摘要:

AbstractParameters of lipid metabolism (triacylglycerols TG, cholesterol CH, HDL‐CH, LDL‐CH, atherogenic index AI, profile of fatty acids) were measured in blood samples of 81 healthy lacto and lacto‐ovo vegetarians (42 males, 39 females; age range 19–39 years). The average period of being on a vegetarian diet was 6.2 years. Low levels of TG, CH, LDL‐CH, AI and HDL‐CH values on the borderline between standard and reduced risk (1.4 mmol middot; 1−1) can be considered as favourable from the atherosclerosis prevention aspect. Compared with non‐vegetarians (n = 62), the levels of TG, CH, LDL—CH, and AI are significantly reduced in the vegetarian group. As opposed to non‐vegetarians, vegetarians showed a higher total sum of polyunsaturated fatty acids, a significantly higher content of linoleic acid (C 18:2) and linolenic acid (C 18:3), unchanged content of oleic acid (C 18:1), stearic acid (C 18:0) and other polyunsaturated fatty acids. The process of lipoperoxidation (with polyunsaturated fatty acids as substrate) is involved in the etiology of cardiovascular and oncological diseases. Favourable values of prooxidative‐antioxidative parameters demonstrated a reduced risk of lipoperoxidation in vegetarians, compared to non‐vegetarians (significantly reduced content of conjugated dienes of fatty acids in plasma, significantly higher plasma levels of vitamin C, β‐carotene, vitamin E/cholesterol ratio — an indicator of LDL protection, vitamin E/triacylglycerols ratio — an indicator of fatty acid protection —, selenium and

ISSN:0027-769X    

DOI:10.1002/food.19960400105

出版商:WILEY‐VCH Verlag GmbH    

年代:1996

数据来源: WILEY

摘要:

AbstractOxidative rancidity in fresh, frozen and cooked chicken breast and leg meat was evaluated by measuring malondialdehyde (MDA) in fat from meat with an improved 2‐thiobarbituric acid (TBA) assay with antioxidant protection, and by measuring the relative fluorescent products of organic and aqueous layers from Folch extracted meat. Fresh samples were frozen for 3 and 6 months at −18 °C and cooked in convection and microwave ovens. Frozen storage for 3 and 6 months either before cooking or after convection and microwave cooking substantially increased MDA concentrations in fat from meat, whereas cooking was more effective in generating fluorescent products. There were no significant differences in free MDA concentrations or TBA numbers in chicken meat between convection and microwave cooking methods. The certain secondary fluorescent products were significantly higher in meat cooked by convection oven. The initial levels of either MDA or fluorescent products in meat are of primary importance in determining the final MDA and fluorescence levels after proces

ISSN:0027-769X    

DOI:10.1002/food.19960400106

出版商:WILEY‐VCH Verlag GmbH    

年代:1996

数据来源: WILEY

摘要:

AbstractCrude aqueous extracts from the peripheral rot zone of cocoyam tubers infected bySclerotium rolfsii saccwere shown to be inhibitory to dialysed in vivo polygalacturonase (PG) of the pathogen. The PG inhibitory action, phenol oxidase and peroxidase activities were higher in cocoyam tubers of theXanthosoma sagittifoliumvarieties than in those of theCoolocasia esculentavarieties. The levels of phenol oxidase, peroxidase and PG inhibitory activities also decreased as the postharvest age of the tubers increased.

ISSN:0027-769X    

DOI:10.1002/food.19960400107

出版商:WILEY‐VCH Verlag GmbH    

年代:1996

数据来源: WILEY

摘要:

AbstractThe present work is a part of research programme aimed to use gamma irradiation to decrease the growth of fungi and the concentration of mycotoxines which present naturaly in collected samples of wheat flour from Egyptian markets (first part). To follow the technological, rheological and chemical characters of bread “Balady” common type in Egypt, same samples of wheat flour were irradiated with 2, 4 and 8 kGy for these purposes. The Egyptian bread type (Balady) had been prepared from irradiated and non‐irradiated samples. The chemical analysis proved a significant induction in reducing sugars (RS) which increased gradually with increasing doses as 16.75%, 30.30%, 43.24% after using 2, 4 and 8 kGy respectively. Same trend was observed with total sugars (TS), less changes were observed in non‐reducing sugars (NRS) and starch content.Results obtained showed that an actual reduction in dough development time, stability, weaking of dough and height of bread especially for irradiated samples at 4 and 8 kGy but 2 kGy was less effective. The reduction of Alkaline Water Retention Capacity (AWRC) was clear at high doses whereas 2.0 kGy improved the freshness of aged “balady” bread.Concerning, the evaluation of organoleptic characters of bread as judged by the panelists, all the samples were accepted either irradiated or not. But, the lowest values of acceptance resulted from irradiated samples with 4 and 8 kGy.Therefore, using 2 kGy can be recommended for keeping quality of wheat flour to avoid the infestation or pathogenic infection. Whereas high doses (4–8 kGy) can be use for eliminating the mycotoxins with some changes of quality which can be overcome by using some additional matters to get more acceptable bread and less changes in technologic

ISSN:0027-769X    

DOI:10.1002/food.19960400108

出版商:WILEY‐VCH Verlag GmbH    

年代:1996

数据来源: WILEY

摘要:

AbstractSelected five spices were treated with simple natural methods as washing with pure tap water then drying at room temperature, thermal treatment at 70 °C/15 minutes besides irradiation with 5.0 and 10 kGy. The evaluation of the used treatments efficiency depends on microbiological and chemical studies. The results show that untreated samples were highly contaminated with pathogenic and toxigenic microbes. Gamma irradiation was effective in decontamination especially 10 kGy but caused losses in major components of flavour as anethol, mechavicul, anise‐aldehyde in anise, β‐pinen and cineol in black pepper. Also, irradiation induced the changes of monoterpene hydrocarbons to alcohol terpens in essential oils of black pepper.Thermal treatment reduced the microbial count and pathogenic microbes to the same safe range as an irradiation dose of 5 kGy. Thermal techniques improved the flavour, as anisealdehyde in fennel, anethol in anise and B‐pinen in black pepper. Washing of the spices removed slightly the microbes but revealed no changes in flavour except the anise flavour which increased markedly.Finally, thermal and washing treatments could be recommended as simple natural techniques to produce spices with good flavour and in safe range for hygienic quality comparing with sterilized dose

ISSN:0027-769X    

DOI:10.1002/food.19960400109

出版商:WILEY‐VCH Verlag GmbH    

年代:1996

数据来源: WILEY

摘要:

AbstractDry yambean seeds, prior to soaking and during storage treatments, were moist cooked and autoclaved. Seeds, presoaked in water, sodium chloride (brine), as filterate (alkali) and a mixture of brine and alkali (alkalibrine) were also similarly cooked. Water and alkali‐soaked seeds became hydrated faster than those pre‐soaked in brine and alkali‐brine solution. When cooked under constant temperature conditions the untreated yambean took about 190 min to cook on a hot plate and kerosene stove and 65 min by autoclaving. Soaking treatments substantially rendered dry yambean more quick‐cooking, especially when pre‐contacted in brine or alkali‐brine for which cooking time was about a third of that of un‐soaked seeds. Yambean cook‐ability declined by 9% after 3 months in storage under room temp

ISSN:0027-769X    

DOI:10.1002/food.19960400110

出版商:WILEY‐VCH Verlag GmbH    

年代:1996

数据来源: WILEY

摘要:

AbstractEffect ofCallosobruchus chinensis(L.) infestation was seen on the carbohydrate and dietary fibre content of chickpea, green gram and pigeon pea at 10, 20, 30, 40, 50 and 60 per cent levels of infestation. With increase in level of infestation energy, starch, total sugars and non‐reducing sugars decreased, whereas significant increase in the reducing sugars, crude fibre, neutral detergent fibre, acid detergent fibre, hemicellulose, cellulose and lignin was observe

ISSN:0027-769X    

DOI:10.1002/food.19960400111

出版商:WILEY‐VCH Verlag GmbH    

年代:1996

数据来源: WILEY