Copper Chloride Crystallisation GESTE 3 (Gestalt Evaluation and Structural Evaluation III) (2016 - 2022)

In recent literature on the assessment of food quality, the matrix, i.e. the structure in which the ingredients are incorporated, is becoming increasingly important. The copper chloride crystallisation method provides information on properties of the matrix/structure of the food by examining the ageing resistance of the whole food.

In copper chloride crystallisation, an aqueous copper chloride dihydrate solution with added plant extract crystallises in the form of juice or extract (Busscher et al. 2010). Spontaneous crystallisation in the form of needles occurs when the saturation limit of the salt solution is exceeded during the phase of evaporation of the liquid. The resulting crystal images are evaluated either with a computer-assisted texture and structure analysis (Andersen et al. 1999, Doesburg and Nierop 2013) or visually (Huber et al. 2010, Doesburg et al. 2015,). Visual evaluation allows conclusions to be drawn about the ageing resistance of the food under investigation by comparing it with reference images of different ageing stages of the food extract (e.g. Fritz et al. 2011, 2017, 2020). A number of coded samples from different cultivation trials were investigated, always showing a higher ageing resistance of organically vs. conventionally grown wheat (Fritz et al. 2011, 2018), grapes (Fritz et al. 2017, 2020), apples (Weibel et al. 2000) and beetroot (Mäder et al. 1993). The GESTE consortium is an expert panel that has documented the methodological principles of visual evaluation of copper chloride crystal images since 2013 and was then trained on these defined criteria. The panel evaluates the ageing resistance of samples from different backgrounds (e.g. fertilisation, cropping systems, varieties, processing: Doesburg et al. 2015, 2021, Fritz et al. 2018).

The Geste group is a consortium of 8 researchers from 4 laboratories, which further develops the visual evaluation of the copper chloride crystallisation method.

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Doesburg, P., Fritz, J., Athmann, M., Bornhütter, R., Busscher, N., Geier, U., Mergardt, G., Scherr, C., 2021. Kinesthetic engagement in Gestalt evaluation outscores analytical ‘atomic feature’ evaluation in perceiving aging in crystallization images of agricultural products.  PLoS ONE, 16(3), e0248124. https://doi.org/10.1371/journal.pone.0248124

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Fritz, J., Athmann, M., Andersen, J.-O., Doesburg, P., Geier, U. & Mergardt, G., 2018. Advanced panel training on visual Gestalt evaluation of biocrystallization images: ranking wheat samples from different extract decomposition stages and different production systems. Biological Agriculture & Horticulture 0, 1-12 https://doi.org/10.1080/01448765.2018.1492457

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Fritz, J., Athmann, M., Meissner, G., Kauer, R. & Köpke, U., 2017. Quality characterisation via image forming methods differentiates grape juice produced from integrated, organic or biodynamic vineyards in the first year after conversion. Biological Agriculture & Horticulture 33, 195-213 https://doi.org/10.1080/01448765.2017.1322003

Fritz, J., Athmann, M., Meissner, G., Kauer, R., Schultz, H.R., 2020. Quality assessment of grape juice from integrated, organic and biodynamic viticulture using image forming methods. OENO one, https://doi.org/10.20870/oeno-one.2020.54.2.2548

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