Browsing by Subject "Egg"

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    Feldstudie zur Eignung der Biophotonenmessung für die Differenzierung von ökologisch und konventionell erzeugten Hühnereiern
    (2009) Egerer, Ulrike; Grashorn, Michael
    Consumer demand for organic food is increasing. Conventional quality criteria are based on assay of individual chemical compounds, which depend much more on local conditions, climate and breed than on the production method. So alternatives need to be found to distinguish between organic and conventional food. Complementary approaches look at biological systems as a whole and focus on the inner structure of products. As shown in many studies, holistic criterions reflect differences in food quality, which are caused by the production method. F.A. POPP has rediscovered ultra weak light emissions that are presumed to originate from electromagnetic fields in living organisms. So-called 'biophotons' can be detected by highly sensitive photomultipliers as 'delayed luminescence' after illumination of the sample. Associated with living processes, the radiation reflects the state of the living tissue. In 2001 B. KÖHLER showed that egg yolks emit varying biophoton intensities depending on the husbandry system. Using standardized test conditions KÖHLER found that exposition to sunlight or to lighting that was similar to daylight, as well as feeding of green stuff, enhanced biophoton emission of yolks. The present investigation has been carried out under conditions of commercial egg production to discover whether biophoton emission is a suitable quality criterion for organic eggs. From July 2005 to November 2006, about 900 eggs have been collected in food stores and on farms. The biophoton intensity of each egg was determined and entered into a database according to its way of production (cage, deep litter, free-range, organic or from smallholders). The aim of this examination was to determine the differences in light emission of eggs originating from various production systems without standardized husbandry conditions. As a second project, a long-term observation has been conducted to see whether biophoton values of eggs remain stable over time. During the course of one year (from May 2006), biophoton emission has been measured each month. Samples have been taken from twelve hen houses with different husbandry systems: 2 houses with cage system, 4 with deep litter, 2 houses with free-range system and 4 organic farms ? adding up to more than 2,300 eggs. In addition to the measurement of biophoton emissions, conventional egg quality criteria have also been determined: egg mass, breaking strength of egg shell, albumen height, yolk color, proportion of yolk, fatty acid profile and lipid oxidation. Farmers have been interviewed about the age of their hens, flock size, lighting conditions and feed composition. Climatic conditions have been researched on the internet. It was expected that comparison of all collected data would give information on the origin and meaning of biophoton emission of egg yolks. In the present studies yolks were exposed to white light for 30 seconds. Delayed luminescence was detected for the duration of 60 seconds. The biophoton parameter used has been defined as the sum of light emission during the last 40 seconds of the measurement. Egg yolks from different animal husbandry systems differed in biophoton emissions. However, while conventionally produced egg yolks showed only minor differences, organic eggs as well as eggs from smallholders were characterized by clearly higher intensities. The long-term observation of yolks from 12 selected hen houses revealed great fluctuation of biophoton emissions over the course of the year. Nevertheless, it was remarkable that yolk samples with low contents of saturated fatty acids and high contents of polyunsaturated fatty acids showed the highest biophoton intensities. These samples originated from farms that offer both a green free range and feed including vegetables or dried grass. As KÖHLER had shown, feeding green stuff leads to higher light emissions of yolks and also influences the profile of fatty acids. Further examinations will be necessary to clarify the causality between fatty acid composition of the yolk and its biophoton emission. Another target of the described projects was to test the suitability of biophoton measurement for verifying the organic origin of eggs. In discriminant analyses egg samples of both studies were assigned to the categories 'organic' or 'conventional' according to their emission values. The hit ratio was about 70 %. This result is interesting considering the lack of techniques to distinguish between organically and conventionally produced eggs up to now. Optimization of measuring technique and procedure may improve the capability of the method. In any case, biophoton measurement could be used as a screening method. Detection of extremely low values would suggest a check of management conditions at the relevant farm, followed by comparison with standards for the respective animal husbandry system.
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    Zweinutzungshuhn – wie schmeckt das? Sensorische Beurteilung von Hühnerfleisch und Eiern von vier Zweinutzungshuhn-Genetiken
    (2023) Gebhardt, Beate; Maute, Jutta; Kiefer, Lukas
    Research into the sensory properties of meat and eggs from dual-purpose chickens has so far been a niche from a scientific point of view. In cooperation with the EIP-Agri project "ZweiWert", students at the DHBW Heilbronn therefore tasted, analysed and evaluated several dual-purpose chicken genetics in the integration seminar "Dual-purpose chickens: How to communicate the added value" in summer 2023. The genetics “Coffee" from the Ökologische Tierzucht (ÖTZ), "Sundheimer" from the Öko2Huhn project, "RegioHuhn" and "Lohmann Dual" as well as a control group from a classic laying or fattening line were assessed. The aim was to find out how different dual-purpose chickens taste and whether there are sensory differences or special features in meat and eggs Sensory attributes, including appearance, taste and smell, were recorded using a multi-methods assessment sheet. In short, the results of this explorative study show that dual-purpose chickens taste better. However, according to the testers judgement, there are differences not only between the different genetics, but also between the individual parts - breast, drumstick, wings or broth. The sensory profiles of the four dual-purpose chickens tested are varied and do not allow a clear sensory "ranking". The meat from Lohmann Dual apparently corresponds best to consumer preferences, while their eggs (cooked) are the least appealing. Overall, however, there is a consistent sensory superiority of the dual-purpose chickens over the specialised fattening or laying breed. These results - should they be confirmed in further studies - could contribute to increasing consumer acceptance of dual-purpose chickens and addressed in market communication to their further spread. The EIP project titled "Building Value Chains for Dual-Purpose Chickens in Baden-Württemberg" (ZweiWert) is funded by the Ministry of Food, Rural Areas and Consumer Protection of Baden-Württemberg from 01/2022 to 12/2024. Project partners include the Naturland Association of Baden-Württemberg, several departments of the University of Hohenheim, and many partners from agricultural production and marketing.