ISSN:0027-769X    

DOI:10.1002/food.19970410302

出版商:WILEY‐VCH Verlag GmbH    

年代:1997

数据来源: WILEY

摘要:

AbstractResults of this study confirm that high temperature (118°C/15 min) and high pressure (400 MPa/5 min) processing of skim milk, skim milk ultrafiltration and ultracentrifugation fractions, and model milk salt solutions cause dramatic shifts in their colloidal and soluble Ca phospate equilibrium that affect their pH, dissolved Ca content, turbidity, and casein micelle microstructure. The relations between high temperature and high pressure processing‐induced changes in the colloidal and soluble Ca phosphate equilibrium were evaluated in raw, pasteurized, and high temperature treated skim milk, ultrafiltration retentate and permeate of pasteurized skim milk, clear ultracentrifugation infranatant of pasteurized skim milk, and synthetic milk ultrafiltrates with and without lactose or Ca. The magnitude of the pH and dissolved Ca shifts caused by high temperature and high pressure processing was a function of casein micelle concentration. Ultrafiltration permeate exhibited the most drastic shifts in pH and dissolved Ca contents due to high temperature and high pressure processing. Although high temperature processing reduced the pH of ultrafiltration permeate from 6.59 to 6.03 and the dissolved Ca from 100% to 58%, high pressure processing reversed both of these changes. These changes in high temperature and high pressure processed milk, milk fractions, and model milk salt solutions were related to microstructural changes in the casein micelles as revealed by electron microsco

ISSN:0027-769X    

DOI:10.1002/food.19970410303

出版商:WILEY‐VCH Verlag GmbH    

年代:1997

数据来源: WILEY

摘要:

AbstractThe concentration of extracellular polysaccharides (EPS) of 80 cereal grain samples of the German harvest 1995 was investigated. In addition to this, the total as well as the inherent mycoflora of two winter wheat and two winter rye brands which showed the highest EPS‐concentration was detected on maltsalt agar (NaCl 5%). Surface disinfection with 1% NaOCl for the determination of the internal mycoflora caused a significant reduction in number and kind of fungi. However, the mycoflora of all samples was dominated by fungi of the generaAlternaria spp.andCladosporium spp., Aureobasidium pullulans, Fusarium spp.andEpicoccum purpurascens(in decreasing order) occurred to a minor extent. A possible contamination of the cereal grains with mycotoxins ofAlternariaandCladosporiumis discusse

ISSN:0027-769X    

DOI:10.1002/food.19970410304

出版商:WILEY‐VCH Verlag GmbH    

年代:1997

数据来源: WILEY

摘要:

AbstractMehrereAmadori‐Verbindungen (Fructose‐Aminosäuren), wichtige Zwischenprodukte derMaillard‐Reaktion, wurden 1991 erstmals in rohen Kakaobohnen nachgewiesen. Durch ein modifiziertes Extraktionsverfahren konnte jetzt auch Fructose‐Phenylalanin (Fru‐Phe) in Rohkakao gefunden werden. Um den Beitrag derAmadori‐Verbindungen als Aromavorstufen zu verfolgen, wurden Fru‐Phe und Fru‐Leu (Fructose‐Leucin) bei 145 °C geröstet und die Röstaromen analysiert. Sie enthielten Schlüsselverbindungen des Kakaoaromas. Durch feucht‐thermische Behandlung und Trocknung ließ sich die Konzentration anAmadori‐Verbindungen in Kakaokernbruch erhöhen und die Aroma‐ausbeute nach Röstung steigern. Der Beitrag vonAmadori‐Verbindungen zur Aromabildung in Kakao scheint erwiesen und k

ISSN:0027-769X    

DOI:10.1002/food.19970410305

出版商:WILEY‐VCH Verlag GmbH    

年代:1997

数据来源: WILEY

摘要:

AbstractGlycoalkaloid levels in different cultivars collected from three regions were monitored during two years. With the exception of Karin, one of the most widely grown cultivar in the Czech Republic, none of the cultivars used for human consumption exceeded the levels considered safe. The average of total glycoalkaloids content for tested cultivars ranged from 31 to 166 mg/kg fresh weight. There were no significant differences between glycoalkaloid levels in tubers from different regions. Attention was paid to the adequate sampling procedure.

ISSN:0027-769X    

DOI:10.1002/food.19970410306

出版商:WILEY‐VCH Verlag GmbH    

年代:1997

数据来源: WILEY

摘要:

AbstractThe effects of illumination, near‐ultraviolet, incubation temperature pH and some minor elements on the growth rate and production of aflatoxin B1byA. flavusand ochratoxin A byA. ochraceuswere investigated. Aflatoxin B1and ochratoxin A production was considerably higher in the light than in the dark. The greatest aflatoxin B1and ochratoxin A production was occurred after 11 days of fermentation with light‐ and dark‐grown cultures at 25 °C. The mycelial dry weight was also greater in the light than in the dark for bothA. flavusandA. ochraceus.Exposure of conidia to near‐UV irradiation increased mycelial dry weight and mycotoxins by both fungi more than white light. The greatest aflatoxin B1and ochratoxin A was at 25 °C with UV‐grown culture (24 h exposure) producing a mean of 400 and 260 μg/50 ml of medium, respectively. The maximum aflatoxin B1and ochratoxin A yield was obtained at pH 5.5 and with increasing the initial pH to near neutrality, both mycotoxins yield decreased. Iron, cupper and zinc were observed to stimulate aflatoxin B1and ochratoxin A production and enhanced the growth rate of bothA. flavusand

ISSN:0027-769X    

DOI:10.1002/food.19970410307

出版商:WILEY‐VCH Verlag GmbH    

年代:1997

数据来源: WILEY

摘要:

AbstractThe object of this work was to present some results from the evaluation of microbiological (total bacterial count, coliform bacteria, aerobic sporogenic bacteria, yeasts and moulds), nutritional (lysine) and sensory (shape, surface, colour, consistency, odour, taste, the profiling of tastiness) quality and of the awvalues of amaranth biscuits and crackers during the four‐month storage (January‐April, 1996 every 30th day) in laboratory conditions (20 ± 2°C and RH = 62 ± 1%). From the aspect of consumers the chosen parameters of quality permitted the storage stability of the indicated non‐traditional products to be estimated and on the basis of the favourable evaluation recommended for the rational n

ISSN:0027-769X    

DOI:10.1002/food.19970410308

出版商:WILEY‐VCH Verlag GmbH    

年代:1997

数据来源: WILEY

摘要:

AbstractFresh marjoram volatiles contained mostly (97%) monoterpenes and to a small extent (3%) sesquiterpenes. The impact of drying methods, namely, convection and microwave drying on the flavour quality of the herb was studied. Cis‐sabinene hydrate, trans‐sabinene hydrate and terpinen‐4‐ol were found to be the major components responsible for the characteristic flavour of the herb. The Indian marjoram contained more of cis‐sabinene hydrate (23.6%) compared to any other sample referred to in the literature and this compound was retained in the convection and microwave (175 W) dried samples to a great extent. Convection drying at ∼45°C preserved the flavour quality of marjoram better than micr

ISSN:0027-769X    

DOI:10.1002/food.19970410309

出版商:WILEY‐VCH Verlag GmbH    

年代:1997

数据来源: WILEY

摘要:

AbstractStudies both on the 2‐thiobarbituric acid assay (fat autoxidation, fat rancidity) and 2‐thiobarbituric acid‐aldehyde reactions were carried out. Physico‐chemical properties in solution of the reagents (2‐thiobarbituric acid, malonaldehyde) and the red adduct, especially, were evaluated. The 2‐thiobarbituric acid structure did not change if heated in diluted acid media (until 1% v/v concentration for strong acids) or in 50% v/v concentration for weak acids, as acetic acid. For high acid concentrations, especially with oxyacids (phosphoric acid, trichloroacetic acid), an oxidant hydrolytical effect can be observed. Diluted solutions of malonaldehyde, in a diluted weak acid medium, remained stable for more than ten days. For the first time the stoichiometries of the red and yellow adducts in solution were determined. Both the absorption maxima and molar absorptivity of the red adduct in acid medium were determined. The neutral and alkaline media were less favourable for the assay sensitivity and stability. The more suitable organic solvents for using in the optimized 2‐thiobarbituric acid assay in aqueous medium were cyclohexane, chloroform and the ethers, because the red adduct was not very soluble (less than 0.1 g/1) in the organic solvents (fa

ISSN:0027-769X    

DOI:10.1002/food.19970410310

出版商:WILEY‐VCH Verlag GmbH    

年代:1997

数据来源: WILEY

摘要:

AbstractGroundnut, coconut and mustard oil treated whole chick pea, mung bean and pigeon pea were infested withCallosobruchus chinensis(L.) and stored for six months. Samples were analysed at monthly intervals for selected B complex vitamins viz. thiamine, riboflavin and niacin. With increase in storage period, values for all the three vitamins decreased in untreated legues. After two months of storage slight decrease in thiamine, riboflavin and niacin content of coconut oil treated legumes was observed which continued till the end of six months as compared to the other two oil treated counterparts. The storage period was associated with insect infestation, which in turn influenced the B complex vitamins of legumes. Groundnut, mustard and coconut oils were able to protect legumes for six months against insect infestation when applied in small amount (0.5%), whereas coconut oil had protective effect against insect infestation only for four months.

ISSN:0027-769X    

DOI:10.1002/food.19970410311

出版商:WILEY‐VCH Verlag GmbH    

年代:1997

数据来源: WILEY