Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Occurrence of pyrrolizidine alkaloids in animal- and plant-derived food : results of a survey across Europe
Mulder, Patrick P.J. ; Lopez Sanchez, Patricia ; Castelari, Massimo ; Bodi, Dorina ; Ronczka, Stefan ; Preiss-Weigert, Angelika ; These, Anja - \ 2018
Food Additives & Contaminants. Pt. A, Chemistry, Analysis, Control, Exposure & Risk Assessment 35 (2018)1. - ISSN 1944-0049 - p. 118 - 133.
eggs - herbal supplements - mass spectrometry - meat - milk - Pyrrolizidine alkaloids - survey - tea

Pyrrolizidine alkaloids (PAs) are secondary metabolites of plant families such as Asteraceae or Boraginaceae and are suspected to be genotoxic carcinogens. Recent investigations revealed their frequent occurrence in honey and particularly in tea. To obtain a comprehensive overview of the PA content in animal- and plant-derived food from the European market, and to provide a basis for future risk analysis, a total of 1105 samples were collected in 2014 and 2015. These comprised milk and milk products, eggs, meat and meat products, (herbal) teas, and (herbal) food supplements collected in supermarkets, retail shops, and via the internet. PAs were detected in a large proportion of plant-derived foods: 91% of the (herbal) teas and 60% of the food supplements contained at least one individual PA. All types of (herbal) teas investigated were found to contain PAs, with a mean concentration of 460 µg kg−1 dry tea (corresponding to 6.13 µg L−1 in [herbal] tea infusion). The highest mean concentrations were found in rooibos tea (599 µg kg−1 dry tea, 7.99 µg L−1 tea infusion) and the lowest in camomile tea (274 µg kg−1 dry tea, 3.65 µg L−1 tea infusion). Occurrence of PAs in food supplements was found to be highly variable, but in comparable ranges as for (herbal) tea. The highest concentrations were present in supplements containing plant material from known PA-producing plants. In contrast, only 2% of the animal-derived products, in particular 6% of milk samples and 1% of egg samples, contained PAs. Determined levels in milk were relatively low, ranged between 0.05 and 0.17 µg L−1 and only trace amounts of 0.10–0.12 µg kg−1 were found in eggs. No PAs were detected in the other animal-derived products.

Milk progesterone measures to improve genomic selection for fertility in dairy cows
Tenghe, Amabel Manyu Mefru - \ 2017
Wageningen University. Promotor(en): Roel Veerkamp; B. Berglund, co-promotor(en): D. J. de Koning; Aniek Bouwman. - Wageningen : Wageningen University - ISBN 9789463431330 - 179
dairy cows - fertility - progesterone - milk - genomics - genetic improvement - heritability - genetic parameters - dairy performance - reproductive traits - animal genetics - animal breeding - dairy farming - melkkoeien - vruchtbaarheid - progesteron - melk - genomica - genetische verbetering - genetische parameters - melkresultaten - voortplantingskenmerken - diergenetica - dierveredeling - melkveehouderij

Improved reproductive performance has a substantial benefit for the overall profitability of dairy cattle farming by decreasing insemination and veterinary treatment costs, shortening calving intervals, and lowering the rate of involuntary culling. Unfortunately, the low heritability of classical fertility traits derived from calving and insemination data makes genetic improvement by traditional animal breeding slow. Therefore, there is an interest in finding novel measures of fertility that have a higher heritability or using genomic information to aid genetic selection for fertility. The overall objective of this thesis was to explore the use of milk progesterone (P4) records and genomic information to improve selection for fertility in dairy cows. In a first step, the use of in-line milk progesterone records to define endocrine fertility traits was investigated, and genetic parameters estimated. Several defined endocrine fertility traits were heritable, and showed a reasonable repeatability. Also, the genetic correlation of milk production traits with endocrine fertility traits were considerably lower than the correlations of milk production with classical fertility traits. In the next step 17 quantitative trait loci (QTL) associated with endocrine fertility traits, were identified on Bos taurus autosomes (BTA) 2, 3, 8, 12, 15, 17, 23, and 25 in a genome-wide association study with single nucleotide polymorphisms. Further, fine-mapping of target regions on BTA 2 and 3, identified several associated variants and potential candidate genes underlying endocrine fertility traits. Subsequently, the optimal use of endocrine fertility traits in genomic evaluations was investigated; using empirical and theoretical predictions for single-trait models, I showed that endocrine fertility traits have more predictive ability than classical fertility traits. The accuracy of genomic prediction was also substantially improved when endocrine and classical fertility traits were combined in multi-trait genomic prediction. Finally, using deterministic predictions, the potential accuracy of multi-trait genomic selection when combining a cow training population measured for the endocrine trait commencement of luteal activity (C-LA), with a training population of bulls with daughter observations for a classical fertility trait was investigated. Results showed that for prediction of fertility, there is no benefit of investing in a cow training population when the breeding goal is based on classical fertility traits. However, when considering a more biological breeding goal for fertility like C-LA, accuracy is substantially improved when endocrine traits are available from a limited number of farms.

Background analysis for a Temporary Measure (State aid) aimed at restructuring the Dutch Dairy Sector
Jongeneel, Roel ; Silvis, Huib ; Daatselaar, Co ; Everdingen, Walter van - \ 2017
Wageningen : Wageningen Environmental Research (Wageningen Economic Research memorandum 2017-054) - 20
dairy farming - agricultural sector - milk - markets - crises - agricultural crises - netherlands - melkveehouderij - landbouwsector - melk - markten - landbouwcrises - nederland
The EU dairy sector is facing a crisis, which also affects Dutch dairy farmers. Low milk prices have negatively affected dairy farm profitability. At the same time, the structural adjustment in the Dutch dairy sector has slowed down: the reduction in the rate of farm exits was below normal levels and in contrast with the pattern observed in several other EU Member States. Now the Dutch government would like to consider a temporary support programme aimed at restructuring the dairy sector. The Ministry of Economic Affairs has requested Wageningen Economic Research to provide a background analysis with respect to such a temporary measure. This analysis is requested because the proposed measure would imply state aid to the Dutch dairy sector, which is only allowable in case a number of criteria are satisfied. This research should provide insight into this matter.
Dry period length of dairy cows : milk composition and quality
Vries, Ruben de - \ 2017
Wageningen University. Promotor(en): Toon van Hooijdonk; K. Holtenius, co-promotor(en): Kasper Hettinga; H.L.M. Lindmark-Månsson. - Wageningen : Wageningen University - ISBN 9789463430463 - 141
dairy cows - dry period - milk composition - milk quality - milk - casein - micelles - melkkoeien - gustperiode - melksamenstelling - melkkwaliteit - melk - caseïne - micellen

A dry period of dairy cows is historically seen as a period during which the cow can restore its body condition and regenerate its mammary epithelium in order to be high yielding in the successive lactation. Recent work has indicated that high yielding cows generally experience a severe negative energy balance in early lactation. Dry period reduction is a strategy to improve the energy balance of dairy cows in early lactation. This thesis aimed at evaluating the influence of dry period length on milk composition and milk quality. Milk composition parameters indicate the processing quality of milk for the dairy plant, and may also reflect the physiological condition and energy status of the cow.

In this work, omission of the dry period was related to a reduced β-casein fraction in early lactation milk. Applying a short (4 weeks) instead of a conventional (8 weeks) dry period resulted in increased plasmin activity in milk, but did not affect the β-casein fraction. Increased plasmin activity in relation to a shortened dry period was particularly found in milk of cows of third or higher parity, that generally had relatively high somatic cell count. At low somatic cell counts, dry period reduction or omission only tended to result in an increased plasmin activity due a higher casein concentration in milk. From increased concentrations of a number of low abundant proteins in colostrum of cows with a short dry period it was hypothesized that a short dry period was related to increased proliferation of mammary epithelial cells during the first days in lactation.

Although the casein composition of milk was related to both plasmin activity in milk and the metabolic status of cows, which are both influenced by dry period length, quantitative differences in casein composition of cows with different dry period length were small. It was concluded that shortening or omitting the dry period of cows with good mammary health obtains milk with a higher protein content with little differences in protein composition.

Determination of energy and protein requirements for crossbred Holstein × Gyr preweaned dairy calves
Silva, A.L. ; Marcondes, M.I. ; Detmann, E. ; Campos, M.M. ; Machado, F.S. ; Filho, S.C.V. ; Castro, M.M.D. ; Dijkstra, J. - \ 2017
Journal of Dairy Science 100 (2017)2. - ISSN 0022-0302 - p. 1170 - 1178.
maintenance - milk - retained energy - starter feed

The objective was to quantify the energy and protein nutritional requirements of Holstein × Gyr crossbred preweaned dairy calves until 64 d of age. Thirty-nine Holstein × Gyr crossbred male calves with an average initial live weight (mean ± SEM; for all next values) of 36 ± 1.0 kg were used. Five calves were slaughtered at 4 d of life to estimate the animals' initial body composition (reference group). The remaining 34 calves were distributed in a completely randomized design in a 3 × 2 factorial arrangement consisting of 3 levels of milk (2, 4, or 8 L/d) and 2 levels of starter feed (presence or absence in diet). At 15 and 45 d of life, 4 animals from each treatment were subjected to digestibility trials with total collection of feces (for 72 h) and urine (for 24 h). At 64 d of age, all animals were slaughtered, their gastro-intestinal tract was washed to determine the empty body weight (EBW; kg), and their body tissues were sampled for subsequent analyses. The net energy requirement for maintenance was estimated using an exponential regression between metabolizable energy intake and heat production (both in Mcal/EBW0.75 per d) and was 74.3 ± 5.7 kcal/EBW0.75 per d, and was not affected by inclusion of starter feed in the diet. The metabolizable energy requirement for maintenance was determined at the point of zero energy retention in the body and was 105.2 ± 5.8 kcal/EBW0.75 per d. The net energy for gain was estimated using the EBW and the empty body gain (EBG; kg/d) as 0.0882 ± 0.0028 × EBW0.75 × EBG0.9050±0.0706. The metabolizable energy efficiency for gain (kg) of the milk was 57.4 ± 3.45%, and the kg of the starter feed was 39.3 ± 2.09%. The metabolizable protein requirement for maintenance was 3.52 ± 0.34 g/BW0.75 per d. The net protein required for each kilogram gained was estimated as 119.1 ± 32.9 × EBW0.0663±0.059. The metabolizable protein efficiency for gain was 77 ± 8.5% and was not affected by inclusion of starter feed in the diet. In conclusion, the energy efficiency for gain of milk is higher than that of starter and the net protein required per unit protein gain increases with empty body weight.

The role of casein micelles and their aggregates in foam stabilization
Chen, Min - \ 2016
Wageningen University. Promotor(en): Erik van der Linden; Toon van Hooijdonk, co-promotor(en): Marcel Meinders; Guido Sala. - Wageningen : Wageningen University - ISBN 9789462579842 - 124
foams - foaming - milk - casein - micelles - physical properties - stabilization - schuim - schuimen - melk - caseïne - micellen - fysische eigenschappen - stabilisatie

Many foam products derived from milk or specific dairy ingredients suffer from drainage, coalescence and/or disproportionation. Previous studies indicated that foam properties of milk are strongly influenced by the composition of the milk as well as by the processing conditions during foam production. The aim of this research was to get a better understanding of these two factors. Interestingly, the presence of aggregates of casein micelles was found to result in very stable foams. The interfacial properties (adsorption speed, adsorption energy, dynamical interfacial tension, interfacial dilatational moduli), thin film stability (rupture time) and foam properties (foamability, drainage, coalescence) of casein micelle dispersions were determined. Based on these data, the very stable foams were concluded to result from properties of the thin films in the foam, which were affected drastically by the presence of the large aggregates of casein micelles.

Impact of microbial variability on food safety and quality
Aryani, D.C. - \ 2016
Wageningen University. Promotor(en): Marcel Zwietering, co-promotor(en): Heidy den Besten. - Wageningen : Wageningen University - ISBN 9789462577381 - 190 p.
listeria monocytogenes - lactobacillus plantarum - growth analysis - kinetics - growth models - inactivation - heat stress - strain differences - food safety - milk - ham - microbial diversity - food quality - groeianalyse - kinetica - groeimodellen - inactivatie - warmtestress - stamverschillen - voedselveiligheid - melk - microbiële diversiteit - voedselkwaliteit
Consumption of dairy foods and diabetes incidence: a dose-response meta-analysis of observational studies
Gijsbers, L. ; Ding, E.L. ; Malik, Vasanti ; Goede, J. de; Geleijnse, J.M. ; Soedamah-Muthu, S.S. - \ 2016
American Journal of Clinical Nutrition 103 (2016)4. - ISSN 0002-9165 - p. 1111 - 1124.
dairy - milk - yoghurt - type 2 diabetes - cheese
BACKGROUND: A growing number of cohort studies suggest a potential role of dairy consumption in type 2 diabetes (T2D) prevention. The strength of this association and the amount of dairy needed is not clear. OBJECTIVE: We performed a meta-analysis to quantify the associations of incident T2D with dairy foods at different levels of intake. DESIGN: A systematic literature search of the PubMed, Scopus, and Embase databases (from inception to 14 April 2015) was supplemented by hand searches of reference lists and correspondence with authors of prior studies. Included were prospective cohort studies that examined the association between dairy and incident T2D in healthy adults. Data were extracted with the use of a predefined protocol, with double data-entry and study quality assessments. Random-effects meta-analyses with summarized dose-response data were performed for total, low-fat, and high-fat dairy, (types of) milk, (types of) fermented dairy, cream, ice cream, and sherbet. Nonlinear associations were investigated, with data modeled with the use of spline knots and visualized via spaghetti plots. RESULTS: The analysis included 22 cohort studies comprised of 579,832 individuals and 43,118 T2D cases. Total dairy was inversely associated with T2D risk (RR: 0.97 per 200-g/d increment; 95% CI: 0.95, 1.00; P = 0.04; I2 = 66%), with a suggestive but similar linear inverse association noted for low-fat dairy (RR: 0.96 per 200 g/d; 95% CI: 0.92, 1.00; P = 0.072; I2 = 68%). Nonlinear inverse associations were found for yogurt intake (at 80 g/d, RR: 0.86 compared with 0 g/d; 95% CI: 0.83, 0.90; P < 0.001; I2 = 73%) and ice cream intake (at ∼10 g/d, RR: 0.81; 95% CI: 0.78, 0.85; P < 0.001; I2 = 86%), but no added incremental benefits were found at a higher intake. Other dairy types were not associated with T2D risk. CONCLUSION: This dose-response meta-analysis of observational studies suggests a possible role for dairy foods, particularly yogurt, in the prevention of T2D. Results should be considered in the context of the observed heterogeneity.
Grondstofefficiëntie in de zuivel-, varkensvlees-, aardappel- en suikerketen
Baltussen, W.H.M. ; Dolman, M.A. ; Hoste, R. ; Janssens, S.R.M. ; Reijs, J.W. ; Smit, A.B. - \ 2016
LEI Wageningen UR (Nota / LEI Wageningen UR 2016-013) - 85 p.
agro-industriële ketens - efficiëntie - duurzaamheid (sustainability) - melk - varkensvlees - aardappelen - suiker - productie - nederland - agro-industrial chains - efficiency - sustainability - milk - pigmeat - potatoes - sugar - production - netherlands
In opdracht van het ministerie van Economische Zaken en Topsector Agri & Food heeft LEIWageningen UR de state-of-the-art in kaart gebracht op het gebied van de duurzaamheidsprestatiesvoor vier belangrijke grondstoffen van de aardappel-, suiker-, varkensvlees- en zuivelketen. De viergrondstoffen zijn: land, water, energie en fosfaat. De focus in dit rapport ligt op de kansen enuitdagingen die er zijn op het gebied van efficiënter grondstofgebruik.
New tools in modulating Maillard reaction from model systems to food
Troise, A.D. - \ 2015
Wageningen University. Promotor(en): Vincenzo Fogliano, co-promotor(en): Claire Berton-Carabin; P. Vitaglione. - Wageningen : Wageningen University - ISBN 9789462575455 - 129
maillard-reactie - maillard-reactieproducten - modulatie - controle - inkapselen - olijfolie - melk - emulsies - modellen - voedsel - gereedschappen - maillard reaction - maillard reaction products - modulation - control - encapsulation - olive oil - milk - emulsions - models - food - tools
New tools in modulating Maillard reaction from model systems to food

The Maillard reaction (MR) supervises the final quality of foods and occupies a prominent place in food science. The first stable compounds, the Amadori rearrangement products (APs) and Heyns rearrangement products (HPs), represent the key molecules from which a myriad of reactions takes place and each of them contributes to the formation of Maillard reaction end-products (MRPs) or advanced glycation end products (AGEs).

Several papers have dealt with the control of the MR in foods ranging from the thermal loading reduction, to the use of alternative process technologies, reactants impact or enzymes, as well as to the monitoring of the end-products formation by multiresponse modeling. The strategies used up to now aim at common goals: the reduction of potentially toxic compounds and the promotion of desired molecules formation as well as flavor, aroma, color and texture attributes. In other words the ultimate target is the promotion of food quality by tuning the MR.

This thesis introduces four alternative strategies that are able to control the final extent of the MR in foods.

The possibility to segregate reactants by encapsulating some minor components and thus delaying the MR was highlighted in Chapter 2. The encapsulation of sodium chloride, ascorbic acid, PUFA and iron inside hydrophobic capsules was used as a possible example: the core material release over the time delayed the reaction rates.

The results obtained through the treatment with the enzyme fructosamine oxidase (Faox) I and II which is able to deglycate free Amadori products and capitalize the local unfolding of lysine peptide bound residues were reported in Chapter 3. Data showed that Faox can reduce the formation ofNε-(Carboxymethyl)-L-lysine and bound hydroxymethylfurfural in model system and in low lactose milk.

The effects obtained with the addition of spray-dried olive oil mill wastewaters in milk was illustrated in Chapter 4. This ingredient acts as a source of phenylethanoids, which can trap a-hydroxycarbonyls and a-dicarbonyls and can form adducts with amino groups after the oxidation of phenolic rings into quinone. The use of this functional ingredient before milk thermal treatment resulted in a reduction of off-flavor, reactive carbonyls species and bound MRPs.

The possibilities offered by the location of MR reactants in microemulsion was investigated in Chapter 5. The oil/water partition coefficient of amino acids played a key role in the formation of Amadori compounds. The anchoring effect of tricaprylin and Tween 20 toward aliphatic amino acids in microemulsion systems was evaluated and compared to a control aqueous solution of amino acids and glucose. Results confirmed the hypothesis: the higher the partition coefficient the lower the formation of aliphatic amino acids Amadori compounds.

All of the four proposed strategies involved location and interaction of reagents, reactants, intermediates and final products. As a result each strategy depicted a specific route for the control of the final extent of the MR. Many steps are still necessary to scale up these methodologies into the food production chain, however new ways for obtaining foods of superior quality have been paved.

Concentrations of dioxins and dioxine-like PCBs in feed material in the Netherlands, 2001-11
Adamse, P. ; Fels-Klerx, H.J. van der; Schoss, S. ; Jong, J. de; Hoogenboom, L.A.P. - \ 2015
Food Additives & Contaminants. Pt. A, Chemistry, Analysis, Control, Exposure & Risk Assessment 32 (2015)8. - ISSN 1944-0049 - p. 1301 - 1311.
toxic equivalency factors - contaminated feed - milk - food - fat - residues - pcdfs - pcdds - eggs
This study aimed to obtain insights into contamination of feed materials used in the Netherlands with dioxins (polychlorinated dibenzo-p-dioxins and dibenzofurans) and dioxin-like polychlorinated biphenyls (PCBs). Monitoring results from the period 2001-11, covering in total 4938 samples, were statistically analysed and evaluated against the statutory limits set at the beginning or during this period. The percentage of samples exceeding maximum levels set within the European Union for either dioxins or the sum of dioxins and dioxin-like PCBs were below 1% for most feed categories, except for fish meal (4.1%), clay minerals (binders and anti-caking agents) (3.4%), and vegetable oils and byproducts (1.7%). For most feed categories, non-compliance with the action threshold (roughly 33% lower than maximum levels) for either dioxins or dioxin-like PCBs was up to three times higher than non-compliance with the respective maximum levels. Exceedance of action thresholds was just above 1% for animal fat, pre-mixtures and feed materials of plant origin excluding vegetable oils. For the categories fish meal, clay minerals, and vegetable oils and byproducts, the action thresholds were exceeded by 5.0%, 9.8% and 3.0% of the samples, respectively. In general, the percentages of samples that exceeded the action thresholds and maximum levels were lower than those reported for the European Union by the European Food Safety Authority (EFSA). In most of the feed materials, there seems to be a decreasing trend in concentrations of dioxins or dioxin-like PCBs over the years. However, a lowering of the limits of quantification during this period and the low concentrations in most samples precludes drawing strong conclusions.
Dynamics of the proteome in human and farm animal milk
Zhang, L. - \ 2015
Wageningen University. Promotor(en): Toon van Hooijdonk, co-promotor(en): Kasper Hettinga; Jacques Vervoort. - Wageningen : Wageningen University - ISBN 9789462574199 - 193
moedermelk - melk - kamelenmelk - proteomen - melkeiwit - melkeiwitten - lactatie - melksamenstelling - melkbewerking - kwantitatieve analyse - kwalitatieve analyse - human milk - milk - camel milk - proteomes - milk protein - milk proteins - lactation - milk composition - milk processing - quantitative analysis - qualitative analysis


The milk proteome changes due to many factors, such as lactation, individual, health status, processing, and species differences. The objective of the work described in this thesis was to increase our understanding of the dynamics of proteome in human and farm animal milk, and its contributions on the improvement of infant formula. This study shows that milk proteome not only differs qualitatively and quantitatively but also differs in their changing rate over lactation between species, especially for immune-related proteins. In addition, milk proteome shows different stability under different processing within and between species. It is concluded that although milk proteome differs between species, the function of milk proteins is essentially the same for all newborns, in providing nutrients and immunity for their growth and development. Both enriching specific milk proteins and mild processing of milk proteins should be considered for the improvement of infant formula.

Heliotropium europaeum Poisoning in Cattle and Analysis of its Pyrrolizidine Alkaloid Profile
Shimshoni, J.A. ; Mulder, P.P.J. ; Bouznach, A. ; Edery, N. ; Pasval, I. ; Barel, S. ; Khaliq, M.A.E. ; Perl, S. - \ 2015
Journal of Agricultural and Food Chemistry 63 (2015)5. - ISSN 0021-8561 - p. 1664 - 1672.
metabolic-activation - senecio-jacobaea - toxicosis - livestock - enzymes - calves - milk
Pyrrolizidine alkaloids (PAs) are carcinogenic and genotoxic phytochemicals found exclusively in angiosperms. The ingestion of PA-containing plants often results in acute and chronic toxicities in man and livestock, targeting mainly the liver. During February 2014, a herd of 15-18-month-old mixed-breed beef cattle (n = 73) from the Galilee region in Israel was accidently fed hay contaminated with 12% Heliotropium europaeum (average total PA intake was 33 mg PA/kg body weight/d). After 42 d of feed ingestion, sudden death occurred over a time period of 63 d with a mortality rate of 33%. Necropsy and histopathological examination revealed fibrotic livers and moderate ascites, as well as various degrees of hyperplasia and fibrosis of bile duct epithelial cells. Elevated ¿-glutamyl-transferase and alkaline phosphatase levels were indicative of severe liver damage. Comprehensive PA profile determination of the contaminated hay and of native H. europaeum by LC-MS/MS revealed the presence of 30 PAs and PA-N-oxides, including several newly reported PAs and PA-N-oxides of the rinderine and heliosupine class. Heliotrine- and lasiocarpine-type PAs constituted 80% and 18% of the total PAs, respectively, with the N-oxides being the most abundant form (92%). The PA profile of the contaminated hay showed very strong resemblance to that of H. europaeum
Two distinct groups within the Bacillus subtilis group display significantly different spore heat resistance properties
Berendsen, E.M. ; Zwietering, M.H. ; Kuipers, O.P. ; Wells-Bennik, M.H.J. - \ 2015
Food Microbiology 45 (2015). - ISSN 0740-0020 - p. 18 - 25.
thermal inactivation - bacterial-spores - sporulation - food - sporothermodurans - strains - systems - milk - stearothermophilus - temperatures
The survival of bacterial spores after heat treatment and the subsequent germination and outgrowth in a food product can lead to spoilage of the food product and economical losses. Prediction of time-temperature conditions that lead to sufficient inactivation requires access to detailed spore thermal inactivation kinetics of relevant model strains. In this study, the thermal inactivation kinetics of spores of fourteen strains belonging to the Bacillus subtilis group were determined in detail, using both batch heating in capillary tubes and continuous flow heating in a micro heater. The inactivation data were fitted using a log linear model. Based on the spore heat resistance data, two distinct groups (p <0.001) within the B. subtilis group could be identified. One group of strains had spores with an average D120 °C of 0.33 s, while the spores of the other group displayed significantly higher heat resistances, with an average D120 °C of 45.7 s. When comparing spore inactivation data obtained using batch- and continuous flow heating, the z-values were significantly different, hence extrapolation from one system to the other was not justified. This study clearly shows that heat resistances of spores from different strains in the B. subtilis group can vary greatly. Strains can be separated into two groups, to which different spore heat inactivation kinetics apply.
Characterization and comparison of phenolic composition, antioxidant capacity and instrumental taste profile of juices from different botanical origins
Granato, D. ; Karnopp, A.R. ; Ruth, S.M. van - \ 2015
Journal of the Science of Food and Agriculture 95 (2015)10. - ISSN 0022-5142 - p. 1997 - 2006.
red wines - vitamin-c - chemical-composition - sensory properties - fruit juices - chemometrics - milk - proanthocyanidins - carotenoids - beverages
BACKGROUND The European Union registered a consumption of about 10.7 billion litres of juices in 2011 and a great part of this amount is imported from other countries, which makes the monitoring of their quality essential. This work was aimed at mapping the quality of various juices from different botanical origins from instrumental taste, chemical marker and antioxidant capacity perspectives. It also characterized the individual phenolic composition of juices previously classified according to their antioxidant activity and total phenolic material level. RESULTS Overall, by using correlation analysis and chemometrics (HCA and PCA), data showed that total phenolics, specifically gallic acid, p-coumaric acid, anthocyanins, flavanols and flavonols, are the main contributors to the antioxidant activity. Elderberry and pomegranate juices presented the highest phenolic content and antioxidant activity. On the other hand, orange, apple and cranberry juices had the lowest levels of total phenolics and flavonoids, DPPH and CUPRAC. CONCLUSION The use of chemometrics coupled to ANOVA seems to be a suitable approach to evaluate the quality of fruit juices from different botanical origins. Additionally, the instrumental taste profile correlated well with the chemical composition and antioxidant capacity, showing its potential application in assessing the functionality of juices
Photopyroelectric assessment of the thermal effusivity of fresh hen egg and of rehydrated egg powders
Szafner, G. ; Nemeth, C. ; Bicanic, D.D. ; Doka, O. - \ 2015
Journal of Thermal Analysis and Calorimetry 120 (2015)1. - ISSN 1388-6150 - p. 363 - 368.
conductivity - diffusivity - parameters - products - heat - spectroscopy - temperature - milk
The availability of thermo-physical data of foods and their constituents is of general importance to food industry. The thermal effusivity e is one among the relevant thermodynamical quantities. The latter is normally calculated from the relationship e = (¿¿c)½, where c is specific heat, ¿ is the density, and ¿ is the thermal conductivity. The necessity for performing the time consuming independent measurements of these three quantities is the major reason that the existing database with effusivity of foods is not very wide. This paper describes the application of the inverse photopyroelectric (IPPE) technique that allows the determination of effusivity from a single measurement. This approach was used to directly measure thermal effusivity of fresh egg yolk, egg white, and white/yolk blends. In addition, thermal effusivity of rehydrated egg powders (white, yolk, and the whole egg powder) has been measured and compared to that of the fresh hen egg. In case of the egg white, effusivity of rehydrated egg powders was practically the same as that of the fresh egg. However, the difference in effusivity between fresh egg yolk and rehydrated egg yolk, and between the blend of fresh egg and the rehydrated whole egg power was significant. Finally, thermal effusivity of rehydrated egg yolk, egg white, and the whole egg powder was determined as a function of dilution factor.
Study on mandatory origin labelling for milk, milk used as an ingredient in dairy products, and unprocessed meat other than beef, pig, poultry, and sheep and goat meat AGRI-2013-EVAL-03 Study Report : Part B – Minor Meats
Baltussen, W.H.M. ; Christodoulou, Maria ; Maréchal, Anne ; Roest, Kees De; Corradini, E. ; Grochowska, Renata - \ 2014
European Commission (EC) - 53 p.
labelling - provenance - milk - milk products - milk production - horse meat - rabbit meat - game meat - cost benefit analysis - consumer information - eu regulations - international trade - european union - etiketteren - herkomst - melk - melkproducten - melkproductie - paardenvlees - konijnenvlees - wild (vlees) - kosten-batenanalyse - consumenteninformatie - eu regelingen - internationale handel - europese unie
Analysis of light scattered by turbid media in cylindrical geometry
Tromp, R.H. ; Liemert, A. ; Meinders, M.B.J. - \ 2014
Langmuir 30 (2014)28. - ISSN 0743-7463 - p. 8276 - 8282.
diffusing-wave-spectroscopy - photon transport - casein micelles - milk - suspensions - dynamics - probes - fluids - foam
The angle dependence of the transmitted light through a cylindrical turbid sample (latex suspension, developing milk gel, draining/coarsening milk, and protein foams) in a standard light scattering setup was analyzed in terms of the transport mean free path length or scattering length l* (a measure for the turbidity) and the absorption length labs. By variation of the concentration of an absorbing dye, the independence of l* and labs was demonstrated. The resulting value of the specific extinction coefficient of the dye was found to be in fair agreement with direct spectroscopic determination and practically identical in milk and latex suspensions. The validity of this technique for obtaining l* was demonstrated by monitoring the acid-induced gelation of milk. The possibility to simultaneously determine l* and labs was used to follow the time development of a draining and coarsening protein foam which contained an absorbing dye. It was shown that labs can be used as a measure for the volume fraction of air in the foam. This method of monitoring the transmission of multiple light scattering provides an easy way to determine l* and, specifically for foams, quantitative data dominated by the bulk of the foam.
Smediger kaas door juiste voer
Hettinga, K.A. ; Dijkstra, J. - \ 2014
De zelfkazer 66 (2014)6. - ISSN 0166-4549 - p. 10 - 11.
kazen - smaak - eiwitgehalte - vetgehalte - voersamenstelling - onverzadigde vetten - vetzuren - melk - melkvet - cheeses - taste - protein content - fat content - feed formulation - unsaturated fats - fatty acids - milk - milk fat
Veel kaasmakers willen smedige (zachte, smeuïge) kaas maken, want de gemiddelde consument vindt die kaas het lekkerst. Kasper Hettinga en Jan Dijkstra van Wageningen Universiteit vertellen hoe de smedigheid van kaas kan worden beïnvloed door de samenstelling van het veevoer.
Short communication: Effect of concentrate supplementation and prolificacy on the productive and economic performance of autochthonous sheep breeds fed forage-based diets
Ripoll Bosch, R. ; Joy, M. ; Sanz, A. ; Blasco, I. ; Ripoll, G. ; Álvarez-Rodríguez, J. - \ 2014
Spanish Journal of Agricultural Research 12 (2014)4. - ISSN 1695-971X - p. 1099 - 1104.
farming systems - milk - sustainability - ewes
Sheep farming systems in Spain are experiencing an intensification process, characterised by a general selection criteria of enhancing prolificacy in ewes, and by increasing indoor feeding with concentrates to the detriment of grazing. This study evaluated the effects of concentrate supplementation and prolificacy on productive and economic performance of a local sheep breed in different price scenarios. Ewes were fed forage hay ad libitum, without (in prepartum period, PRE-HAY; and in post-partum period, POST-HAY) or with concentrates (300 g d–1 in pre-partum period, PRE-CON; and 750 g d–1 in post-partum period, POST-CON). The inclusion of concentrate during the pre-partum period (last 10 weeks of pregnancy) had no effect on the productive performance of the ewes. In contrast, the inclusion of concentrate in the post-partum period (6 weeks), resulted in greater milk yield (1009 vs. 1275 ± 89 g d–1), lamb average daily gain (151 ± 12 vs. 225 ± 19 g d–1) and lamb output (kg of lamb LW weaned). However, the greater productivity thanks to the use of concentrates did not always turn into greatest profitability, since the economic margin was highly influenced by the cost of the diet and extremely subjected to variability in price of concentrates. Hence, the inclusion of concentrates in sheep meat production was not always justified in economic terms. In conclusion, the use of concentrates should only be considered as long as prices of commodities remain low, and inadvisable when prices reach a certain threshold or are subject to certain volatility in markets.
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