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1.
BACKGROUND: Very few studies concern the effects of layer housing systems and age on egg technological properties. Thus the aim of this work was to study the influence of these two factors on egg performance in fresh pasta production, focusing on pasta cooking behaviour. Samples of pasta subjected to analysis were prepared with eggs laid by Hy‐Line Brown hens (from 27 to 68 weeks old) housed in cage, barn and organic systems. RESULTS: Higher average values of weight increase and matter loss during pasta cooking were observed for samples prepared with eggs laid by older hens. Such cooking behaviour indicated the development of a weaker pasta protein network, resulting from a decrease in the quantity of albumen protein and an increase in fat content, which is due to the reduction in albumen/yolk ratio during hen aging. The housing system had a significant effect only on matter loss in cooking water, but differences between samples were so small as to be unlikely perceived by consumers. CONCLUSION: Both hen age and housing system significantly affected pasta cooking behaviour, but the greatest effect was exerted by the hen age. Copyright © 2010 Society of Chemical Industry  相似文献   

2.
The influence of egg pasteurisation and of thermal treatment(s) of fresh egg pasta on the protein network in the pasta were studied. Protein structural parameters were correlated with the physico-chemical and rheological characteristics of pasta. Twelve samples of fresh egg pasta were laboratory-produced, using raw or pasteurised whole egg, and either left untreated or submitted to one or two pasteurisation processes. Industrial pasteurisation of the eggs did not affect the protein network of pasta or its rheological and functional characteristics. Double thermal pasteurisation of egg pasta deeply influenced its structural characteristics, due to the formation of a tight protein network stabilised by disulfide bonds, in which ovalbumin plays an essential role. This tight protein network affected the cooking behaviour and the rheological properties of fresh egg pasta, decreasing weight increase upon cooking and break strain, while increasing break load and Young modulus. The indexes derived from these studies were applied to the characterisation of 24 commercial samples of fresh egg pasta. By using the Young modulus before and after cooking (rheological parameters) and protein solubility in buffer-saline (structural parameter), it was possible to discriminate three groups of samples as a function of the severity of their thermal treatment.  相似文献   

3.
BACKGROUND: The use of antibiotic growth promoters in animal feeds is not approved for laying hens in many countries, and economically feasible biological measures which include probiotics are developed to improve hen performance. The present study investigated the effects of probiotics on hen performance for a 48‐week period and the cholesterol, total lipid and fatty acid composition of egg yolk at 24, 28 and 32 weeks of age. RESULTS: Egg weight of Lactobacillus culture (LC)‐fed hens was significantly (P < 0.05) greater than that of control hens throughout the laying period. From 20 to 44 weeks of age, LC‐fed hens produced a significantly (P < 0.05) lower percentage of small eggs and a higher percentage of large eggs, and from 45 to 68 weeks of age a significantly (P < 0.05) lower percentage of medium eggs and a higher percentage of large and extra‐large eggs than control hens. Significantly (P < 0.05) less cholesterol was found in egg yolks of hens fed LC at 24 and 28 weeks of age, but not at 32 weeks of age. The total lipid content and the fatty acid composition of egg yolks were similar between the treatments at 24, 28 and 32 weeks of age, except for stearic acid (C18 : 0), which was significantly reduced in the egg yolk of LC‐fed hens at 28–32 weeks of age. CONCLUSION: The greatest benefit of LC was in increasing egg weight and improving egg size by influencing a shift from small and medium to large and extra‐large eggs. Copyright © 2008 Society of Chemical Industry  相似文献   

4.
The aim of this study was to determine whether anti-ovarian autoantibodies appear in the circulation of laying hens and whether the concentrations of these antibodies change with respect to ageing and egg laying rate. Autoantibodies to ovarian tissues in the circulation of aged (aged approximately 670 days) White Leghorn hens with low (< 50%) and high (> 90%) egg laying rates were examined by ELISA and western blotting. Young laying hens (aged 185 days) with > 95% egg production were used as controls. The results of the ELISA indicated that IgG, which bound to the ovary and small white follicles, was present in the circulation of old laying hens. More hens that laid few eggs had circulatory autoantibodies to the ovary and small white follicles, as determined by the cut-off value in ELISA (mean absorbance + 2 SD of young laying hens), than did hens that laid greater numbers of eggs, and the concentration of IgG was significantly higher in the hens that laid few eggs. In contrast, when the muscle proteins were used as antigens there were no significant differences in the absorbance values among low and high laying frequency old hens or young hens. Western blotting revealed many bands of immunoprecipitates formed by ovarian antigens and antibodies in the serum of old hens, indicating the presence of many binding sites for circulatory IgG in ovarian tissues. These results indicate that antibodies to ovarian tissues appear in the circulation of laying hens during ageing, and that the concentration of these autoantibodies is related inversely to the rate of egg laying by hens.  相似文献   

5.
To evaluate the nutritional significance of cumin seed meal (CSM) as a commercial poultry feedstuff on laying hen performance and quality of laid eggs, an experiment was conducted using 144 (48‐week‐old) laying hens receiving diets containing 0, 25 and 50 g CSM kg?1 with or without polyethylene glycol (PEG 6000) and xylanase enzyme (Grindazym? GP 15000) for 9 weeks. Body weight on the first and last days of the experiment and daily egg production and egg weight and weekly feed intake during the first, fifth and ninth weeks of the experiment were recorded. Shell weight, shell thickness, Haugh unit and yolk colour were measured during the last week of the experiment. The results showed that inclusion of CSM in laying hen diets had no negative influence on the parameters measured compared with the control diet (P > 0.05), but enhanced egg yolk colour (P < 0.05). PEG increased the daily feed intake of birds receiving CSM diets (P < 0.01) and tended to enhance daily egg production and egg weight, although not significantly. Grindazym decreased shell weight and thickness of laid eggs (P < 0.05) and tended to increase hen body weight, but had no influence on other parameters measured. The results demonstrated that CSM can be substituted for wheat bran in layer diets at 25 or 50 g kg?1 dietary inclusion level without any adverse effect on hen performance or egg quality, and might enhance egg yolk colour. In view of the low price of CSM, it could be concluded that inclusion of CSM in the diet might be beneficial to the commercial laying hen industry and reduce the overall cost of egg production. Copyright © 2006 Society of Chemical Industry  相似文献   

6.
Hypocrellins, including hypocrellin A and hypocrellin B, are natural red pigments isolated from a traditional Chinese medicine. The present work was designed to investigate the influence of dietary HA supplementations on the colour and emulsifying properties of egg yolk and HA distributions in tissues of laying hens. A Chinese hen breed (black-bone silky fowl) was used. Ninety-six layers were assigned randomly to diets containing 0, 10, 30 and 50 mg HA per kilogram for 21 days. HA concentrations in egg yolk and tissues of laying hens such as ovary, liver, lung, heart, gizzard and breast muscle were determined by HPLC. Dietary HA supplementations improved the colour of egg yolk (P < 0.05), whereas no significant differences (P > 0.05) in the emulsifying properties of egg yolk were observed. There was a dose-dependent manner increase in egg yolk HA content in response to dietary HA supplementations (P < 0.05). The highest HA concentration was measured in ovary followed by liver and egg yolk.  相似文献   

7.
Cholesterol oxidation was studied in 12 samples of mass-produced egg pasta and in home-made egg pasta produced with fresh eggs obtained from hens bred in the open with organic methods (a), fresh eggs purchased in a local retail shop (b) and spray-dried eggs, which are not allowed by Italian law (c). The lipids of commercial egg pasta contained almost twice the concentration of cholesterol of hand-made egg pasta (2.6 vs. 1.4 mg/100 mg lipids). Mass-produced egg pasta contained 2.2±1.5 g oxycholesterols (cholesterol oxidation products, or COPs)/g of pasta, Epo being the most represented oxycholesterol. The oxycholesterol content in home-made pasta was 1.7, 3.5 and 3.6 g/g pasta, for pasta obtained with samples a, b and c, respectively. 7-Hydroxycholesterol and -epoxy-cholesterol were not taken in account, because they co-eluted with campesterol and campestanol, respectively. The home-made procedure (eggs mixed with flour and water and dried for 48 h at 30 °C) led to the formation of 7 k and 7, rather than Epo. The use of eggs from hens bred in the open reduced the COPs content considerably. The home-made product should be consumed within a few days after manufacturing or should be immediately refrigerated.  相似文献   

8.
As part of a study of the reasons for the large effects of a small dietary supplement of methyl sterculate on the physical properties and lipid composition of hen's egg yolk, individual yolks from sterculate-fed hens have been examined. These yolks set to a firm gel on cooling in the range 20-0 °C, but there were large variations in eggs from different hens that were accompanied by variations in the proportion of saturated fatty acid residues in the yolk lipids. Gel formation was reversible on immediate rewarming but prolonged storage at low temperature caused irreversible alterations. Diluted yolk showed analogous changes in viscosity on cooling and provided a convenient model system for examining the effect of pH, ionic strength, and the action of trypsin. From these results it is concluded that the protein of the high-lipid low-density lipoprotein of yolk is directly involved in the gelation of the yolk. A series of eggs laid by one sterculatefed hen over 30 days showed large and possibly periodic variations in the lipid composition and gelation temperature of the yolks. These results and some data from other hens suggested that large variations in yolk properties accompany a high response to sterculate feeding.  相似文献   

9.
Vaccination of hens withSalmonella enteritidis(SE) bacterin has become an important industry management tool to reduce both the incidence of SE in flocks and the production of SE-contaminated eggs. After vaccination, antibodies to SE can be found in both the serum and egg yolks. The current study was undertaken to examine whether the antibodies deposited in eggs after vaccination would have any effect on thein vitrogrowth of 10 SE seeded into pooled egg contents and incubated at 37°C for 24 h. The SE inoculum grew well in egg contents from control-vaccinated hens, and a high percentage of these samples were culture positive for SE. Conversely, significantly fewer egg contents from vaccinated hens were positive for SE at weeks 2, 3, 4, and 5 post-primary vaccination and weeks 1, 2, and 4 post-secondary vaccination. After 24 h incubation, the SE inoculum grew to 108–109organisms ml−1in egg contents from control hens, while growing to less than 104organisms ml−1in egg contents from vaccinated hens. No inhibition of growth was observed for a second organism,Proteus mirabilis, in egg contents from bacterin-vaccinated hens, indicating antigen-specificity of the activity. Inhibition of SE growth was observed in egg contents from vaccinated hens diluted 1:5 in eggs from control hens. Mixed results were observed for egg contents receiving a 10-fold higher SE inoculum with significant inhibition of growth observed in one trial and minimal inhibition observed in a second trial. Supplementing the egg samples with an iron source abrogated the inhibition, suggesting that the iron- restricted environment found in eggs may play a role in the observed inhibition.  相似文献   

10.
Effects of freezing assisted with magnetic fields (MFs) in a Cell Alive System (CAS) commercial unit at 50 °C, with a static MF only (0% CAS) and with a static MF plus oscillating MF (10% CAS) on egg white (W) was investigated. W samples were from commercial eggs from three strains of laying hens (two of them living in fortified cages and the third one in liberty at outdoor). The main goal was to follow the protein thermal denaturation involved in W processing. Thermal denaturation enthalpy was markedly affected (~ 50% total protein in comparison with fresh sample) but similar for both MFs processes, where 0% CAS was taken as Control freezing treatment. MFs effects were predominantly thermal in nature and constituted the factor with the highest influence on thermal behavior, as well as on the majority of the functional properties exhibited by MFs samples. Rheology and free Sulfhydryl content were studied complementarily to Differential Scanning Calorimetry (DSC) data. Some important functional properties as Foaming parameters and Texture of W gel were also determined. The hen strains-feeding factor did not practically influence the physical or functional behaviors of both untreated and processed W samples.  相似文献   

11.
Nissan Kassis 《LWT》2010,43(5):777-73
Novel, nutritionally-enhanced egg products were developed by substituting saturated fat and cholesterol-containing yolk with omega-3 fatty acids-rich (ω-3 FA) flaxseed, menhaden, algae, and krill oils. The ω-3 FA-fortified eggs are typically developed through alteration of hen feed. However, the present study aimed at creating such a product via processing. Experimental egg products were developed to match composition, color, and texture of hen eggs (mixed whole egg). Experimental egg products, mixed whole egg, and liquid egg product (Egg Beaters™) were cooked, analyzed, and compared. Moisture, protein, and fat content of experimental egg products matched (P > 0.05) whole egg. The L (lightness) for experimental egg products was generally similar to mixed whole egg except when krill oil was added. Experimental egg products had higher (P < 0.05) a and b than mixed whole egg and Egg Beaters™, indicating more redness and yellowness, respectively. Texture profile analysis (TPA) values (hardness, springiness, cohesiveness, gumminess, chewiness, and resilience) revealed that experimental egg products had similar (P > 0.05) and greater (P < 0.05) textural properties when compared to mixed whole egg and Egg Beaters™, respectively. Fundamental torsion test confirmed that experimental egg products and mixed whole egg had generally similar texture, but were firmer (P < 0.05) than Egg Beaters™. Kramer shear test indicated a trend (P > 0.05) of slightly firmer texture for experimental egg products than Egg Beaters™.  相似文献   

12.
An investigation was carried out to assess the possibility of using single dietary sources as alternatives to feed deprivation for the induction of moult in commercial laying hens. The study involved six dietary groups of 29 laying hens: unmoulted, dried tomato pomace, alfalfa meal, rice bran, cumin seed meal and feed withdrawal. The birds received the above diets during the moulting period (11 days), and body weight loss and ovary weight regression were measured. Post‐moult production parameters (number of eggs produced per hen per day, egg weight, shell weight, yolk colour and Haugh unit) were measured for 12 weeks. Results showed that all dietary sources were as effective as feed withdrawal in causing ovary weight regression in birds. Birds provided with tomato pomace or alfalfa showed lower weight losses than feed‐deprived birds at the end of the moulting period. Hens moulted by tomato pomace or alfalfa exhibited post‐moult levels of egg production over a 12 week period that were superior to those of hens moulted by feed withdrawal. Post‐moult eggs laid by hens moulted by all dietary sources were of comparable quality to eggs from feed‐deprived hens and superior to those from unmoulted hens. As fibrous feeds with low metabolisable energy and an appreciable amount of protein, dried tomato pomace and alfalfa meal may be fed to hens on an ad libitum basis for effective moult induction while reducing the stress of severe starvation and retaining comparable egg quality and production. Copyright © 2007 Society of Chemical Industry  相似文献   

13.
Folate content in eggs from three different breeds of hens fed with three different feeds, one organic and two conventional, was compared using a simplified microbiological assay. Retention of folate when boiling the eggs was also studied. Folate content in eggs did not differ significantly due to the breed of hen or the feed used. The loss of folate when boiling the eggs was 9%. The results from the microbiological assay were confirmed by LC/MS. According to this study, 1 egg (60 g) provides 40–50 μg of folate. This corresponds to 13–17% of the recommended daily intake, 300 μg for adults in the Nordic Nutrition Recommendations. The folate forms found in egg yolk with LC/MS were 5-methyl-tetrahydrofolate and 10-formyl-folic acid, whereas no folates were found in egg white. In this study, no polyglutamate folate forms could be detected in eggs.  相似文献   

14.
The aim of this work was to study the foaming, gelling and rheological properties of albumen as simultaneously affected by the housing system (i.e. conventional cage, organic and barn) and the age of layers (27, 30, 35, 43, 53 and 68 weeks). Significant effects of the two considered factors and of their interactions were found for almost all the studied properties. In particular, with the increasing of the hen age, a loss in albumen consistency and a weakening of the albumen gel structure were observed. As regards the housing system, differences observed, even if statistically significant, were little and unlikely to have a real effect on technological performances of the eggs when used as food ingredients. Significant correlations amongst technological properties of albumen and its pH and protein content were also found.  相似文献   

15.
Experiments were carried out in the laboratory with the aim of accessing the effectiveness and parasitism by Trichogramma evanescens to prevent Corcyra cephalonica from infesting rice in paper and jute bags. Eight small jute or paper bags filled with 5 kg of organic rice grains were prepared and the openings sealed. Sentinel egg cards were prepared with thirty fresh eggs of C. cephalonica glued onto small pieces of paper cardboard. Eight sentinel egg cards were introduced into a plastic box measuring 60 × 40 × 21 cm, i.e four cards on top surface of the bag and the box bottom, respectively. Approximately 500 adults of T. evanescens were released 10–30 cm away from the egg cards. The control boxes contained no parasitoids; there were five replicates for all treatments and controls. Two experimental conditions were tested, i) placing a single T. evanescens-release unit with sentinel egg cards placed every 3–4 days without any further replacement of the release unit for three weeks, ii) both new host eggs and T. evanescens release units were replaced every 3–4 days. Mean emergence of C. cephalonica was significantly (p > 0.001) suppressed by the release of T. evanescens. There was statistically no significant difference on the number of emerged moths on paper bag compared to jute bag. All sentinel egg patches were visited by T. evanescens. There was no correlation between the distance (10–30 cm) at which the sentinel egg cards were placed away from the T. evanescens release point and the number of parasitized C. cephalonica eggs. There was no decrease in parasitism over time. The results demonstrate that T. evanescens has the potential for host-location ability and parasitism of C. cephalonica both on paper and jute bags. This parasitoid could be a promising candidate for the biological control of moth pests in bagged stored products.  相似文献   

16.
Development of gluten-free fresh egg pasta analogues containing buckwheat   总被引:1,自引:0,他引:1  
To improve the use of common buckwheat (Fagopyrum esculentum), characterized by interesting nutritional properties, it could be used in pasta formulations. In particular, as buckwheat is devoid of the gluten-forming proteins, it might be an ingredient for celiac patient food. The aim of this study was to develop both fresh egg pastas integrated with buckwheat and fresh egg pasta analogues classifiable as gluten-free, based on buckwheat and rice flours. Matter loss in the cooking water and weight increase during cooking of buckwheat pasta were higher than those of a reference sample made of common wheat flour. As buckwheat integration increased, sample break strain was significantly lower, as a result of the progressive reduction in gluten content. In the production of gluten-free pasta analogues, wheat flour was substituted with rice flour, precooked rice flour or pregelatinized rice starch. Since samples containing precooked rice flour gave the best results, in terms of workability, break strain and weight increase during cooking, they were also produced on an industrial scale. Industrial gluten-free fresh egg pasta analogues were tougher and less deformable in comparison with the laboratory-produced samples. These results were determined by the presence of the double thermal pasteurisation treatment, which allows to obtain a better structure of the product, showing also a lower matter loss during cooking.  相似文献   

17.
Sixty Hy-line brown hens were randomly assigned to four barns (n = 4) to investigate the effects of cholecalciferol (vitamin D₃) versus 25-hydroxyvitamin D3 (25-OH-D₃) enriched diets on egg vitamin D concentration, antioxidant activity and egg quality parameters. Experimental design was a 4 × 4 Latin square consisting of 4 experimental treatments and 4 experimental periods. The treatments were (1) 1500 IU of vitamin D₃ (2) 3000 IU of vitamin D₃ (3) 1500 IU of vitamin D₃ and 37.5 μg of 25-OH-D₃ (4) 75 μg of 25-OH-D₃ per kg of feed. Hens offered 75 μg of 25-OH-D₃ had a higher (P < 0.05) total vitamin D egg yolk content (5.06 μg/egg), and antioxidant activity compared to other dietary treatments. The results demonstrates that the enrichment of hen diets with 25-OH-D₃ may be a useful approach and may contribute between 25 and 33% towards total vitamin D daily requirements while also improving antioxidant status of eggs.Industrial relevanceVitamin D deficiency is now regarded as a major issue in northern Europe and has been described as a pandemic. A growing interest in vitamin D food fortification in northern Europe to satisfy the current dietary intake recommendations has been observed. The use of a bio-addition approach for increasing vitamin D intake through biofortification of livestock feeds attracts attention. Enrichment of the hen's diet with vitamin D may also supply additional benefits of increasing antioxidant activity. This increase in antioxidant activity may have the ability to increase food quality and extend the shelf life. This study explores the effect of vitamin D enriched diets fed to laying hens on vitamin D egg yolk content and antioxidant activity in the egg. These enriched diets could demonstrate that enrichment of hen diets with 25-hyroxvitamin D₃ may be a useful approach for tackling low vitamin D intakes and improving antioxidant capacity of eggs.  相似文献   

18.
A tannins-rich chestnut extract was used to enhance the antioxidant and antibacterial properties of chitosan-based film materials. The favourable mechanical properties of the novel material enabled its application in the preparation of the sachets that were used for packing and storage of filled fresh pasta. The fresh pasta ageing progressed in conventional refrigerated storage conditions of 8 °C with 60 ± 2% relative humidity in the absence of light for 60 days. The rapid moisture mobility between a starchy food and sachets during the first 9 days of storage induced retrogradation of the fresh pasta, whereby total phenolic content show dependency on moisture throughout the shelf life. Active components within the sachet prevented microbial growth on the food surface during the entire 60 days.  相似文献   

19.
A 16‐wk feeding experiment was conducted to investigate the effects of a prebiotic, isomaltooligosaccharide (IMO), a probiotic, PrimaLac®, and their combination as a synbiotic on the chemical compositions of egg yolks and the egg quality of laying hens. One hundred and sixty 16‐wk‐old Hisex Brown pullets were randomly assigned to 4 dietary treatments: (i) basal diet (control), (ii) basal diet + 1% IMO (PRE), (iii) basal diet + 0.1% PrimaLac® (PRO), and (iv) basal diet + 1% IMO + 0.1% PrimaLac® (SYN). PRE, PRO, or SYN supplementation not only significantly (P < 0.05) decreased the egg yolk cholesterol (24‐ and 28‐wk‐old) and total saturated fatty acids (SFA; 28‐, 32‐, and 36‐wk‐old), but also significantly (P < 0.05) increased total unsaturated fatty acids (UFA; 28‐, 32‐, and 36‐wk‐old), total omega 6 and polyunsaturated fatty acids (PUFA), including linoleic and alpha‐linolenic acid levels in the eggs (28‐wk‐old). However, the total lipids, carotenoids, and tocopherols in the egg yolks were similar among all dietary treatments in the 24‐, 28‐, 32‐, and 36‐wk‐old hens. Egg quality (Haugh unit, relative weights of the albumen and yolk, specific gravity, shell thickness, and yolk color) was not affected by PRE, PRO, or SYN supplementation. The results indicate that supplementations with IMO and PrimaLac® alone or in combination as a synbiotic might be useful for improving the cholesterol content and modifying the fatty acid compositions of egg yolk without affecting the quality of eggs from laying hens between 24 and 36 wk of age.  相似文献   

20.
Effects of α‐ and β‐chitosan (CH), soybean oil (SO) and their emulsions (CH:SO = 2:3) as coating materials on selected internal quality and sensory properties of eggs were evaluated during 5 weeks storage at 25 °C. After 3 weeks of storage, α‐ and β‐CH‐coated eggs changed to B grade, while SO‐ and emulsion‐coated eggs preserved grade A quality. Weight loss of eggs coated with SO and CH:SO emulsions was <2.0% vs. 5.3–5.8% for noncoated and CH‐coated eggs after 5 weeks of storage. β‐CH (0.9%) maintained lower weight loss of eggs than α‐CH (1.2%) only at 1‐week storage. Albumen pH of eggs coated with SO and CH:SO emulsions decreased progressively throughout storage. Eggs coated with β‐CH:SO emulsion and SO were significantly glossier than noncoated eggs. Consumers indicated positive purchase intent (69.17–76.67%) for all coated eggs. Overall, α‐CH:SO and β‐CH:SO emulsions extended egg shelf life by at least 3 weeks during room temperature storage.  相似文献   

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