Parameters for apple quality: and an outline for a new quality concept - part 1 report

In real life it is hard to distinguish between the two life processes, growth and differentiation. We cannot expect one measured parameter to represent only one aspect of vital quality. But for most parameters we can recognise emphases on one or more aspects of the vital quality concept. We made this prelimary classification both by thinking about the concept and by looking at the experimental results. Also the conventional parameters are interpreted as a result of these processes in a more holistic way than usual. We realise that various parameters all concerning the same aspect of our quality concept can show different levels of the aspect. To belong to the same aspect of the quality concept does not automatically mean that their correlation (see annex 14.2) must be high. We still have to get a lot of more experience to validate the parameters’ character. Here we present our first research on this topic, including the unanswered questions and realise that more experimental series will bring more and more certainty. After this first project we cannot say which parameters are so similar that it makes the other redundant. Until now we learned something from every parameter to develop our quality concept. Most inspiring for the new quality concept were the crystallisations, the delayed luminescence and the Bovis-value

Parameters for apple quality - 2 - and the development of the ‘inner quality concept’ 2001-2003

We found clear correlations between management measures, tree characteristics and fruit characteristics. This means that growers can regulate apple quality during the growing season. On the basis of the two apple experiments, we can distinguish respective sets of growth and differentiation parameters and evaluate them in the light of conventional fruit cultivation science. Our results have little new value for fruit growing in practice, however. The value of our research lies in the approach developed to draw up a quality concept and the way in which we can apply this concept to crops about which little knowledge exists regarding the relationship between management measures, crop characteristics and product quality characteristics. Our research also offers a method to validate experimental parameters

The effect of water activity and temperature on the production of some mycotoxins

Preventing mold from growing and producing mycotoxins requires knowledge of the conditions under which each of the toxinogenic molds becomes active. In this investigation the relation between fungal growth and mycotoxin formation and the factors water activity and temperature is studied. Various fungal species known to produce mycotoxin were tested. Optimal substrates for production of the particular mycotoxin were used to determine the lowest possible water activity and temperature at which mycotoxins may be produced.In article 1 a water activity measurement device is described which has been designed for accurate measurements. The first study encompasses the aflatoxin production by Aspergillus parasiticus at different conditions of water activity and temperature. Experience is gained with both liquid cultures and surface cultures. Because of its reproducibility and resemblance to mold growth in practice, the surface culture is preferred and used in the following investigations.In article 2 attention is paid to differences between Aspergillus flavus strains in their response to various conditions of water activity and temperature.In articles 3, 4 and 5 the results of similar investigations with patulin, penicillic acid and ochratoxin A, respectively, are described and discussed. The effect of water activity and temperature on mycotoxin production is studied with semi-synthetic agar media, but also with some natural substrates.In the last experimental section of the thesis the effect of water activity and temperature on the mycotoxin production rate and mycotoxin production lagtime of the four mycotoxins is described. For this a calculation model is developed to exclude the influence of mycelial weight and growth time on the outcome of the experiments.In the chapter Discussion the results of articles 1-5 are discussed in the light of the results described in the last experimental section. In a final discussion the practical implications of the results with respect to safeguarding of foods from mycotoxin contamination are considered.<p/

The Inner Quality Concept for food, based on life processes

How can we adequately express the quality of food produced by organic agriculture? To answer this research question, we defined a concept of ‘inner quality’ (formerly called ‘vital quality’) based on the life processes growth and differentiation, and their integration. Growers use management methods to influence life processes in their crops, thus optimising the quality of the final product. Traders and consumers can recognise certain product properties as being the result of these life processes. Here, we present a course of validation for the quality concept, together with appropriate quality parameters. The process of validation has been completed in part for two experimental crops, apple and carrot. This quality concept can provide a holistic context for the interpretation of individual food quality parameters as developed by different laboratories

Parameters for Carrot Quality: and the development of the Inner Quality concept

The life processes of the carrot plant were demonstrated by various parameters in this study. Growth processes, including photosynthesis, absorption of nitrogen and other nutrients and formation of cells, tissues and organs, are measured by the parameters weight of leaves and roots and emission 30-50 white of delayed luminescence. The nitrate content may indicate growth but has to be investigated further. Differentiation processes, including refining, ordering, ripening and secondary metabolisms, are measured by the parameters root stumpiness, saccharose, sweetness, dry matter and emission 30-50 ratio of delayed luminescence. Some other parameters may indicate differentiation processes but have to be further investigated: leaves/root weight ratio, monosaccharides/saccharose ratio, carotenes, initial and total emission white, hyperbolicity ratio and slope white of delayed luminescence. Integration of growth and differentiation is measured by resistance to pests and disease, total appreciation and storage test. Some other parameters may indicate integration but need further investigation: carrot taste, slope white of delayed luminescence. Copper chloride crystallisation did not produce clear pictures due to failure of the method applied and should be further investigated since, in the Apple-1 and -2 studies (Bloksma et al., 2001, 2004 b), it was one of the indicators of the life processes. Electro-chemical parameters, except possibly pH, did not indicate growth processes in his study or in the Apple-1 and -2 studies

Contaminants and micro-organisms in organic and conventional food products

In the Netherlands we investigated animal and plant products on potentially hazardous contamination with heavy metals, mycotoxins, pesticide residues, patho-genic micro-organisms and nitrate. In most cases, the organically produced foods had equal or lower amounts of contaminants than conventionally pro-duced products. These results conflict with a common idea that organic farming theoretically increases food safety risks. For many contaminants organic food showed a large diversity in the amount of contamina-tion. Experience with organic farming, managing and manure use partly explain these differences. Understanding of these cultivation parameters can help in further improvement of organic cultivation practices

Polyphasic identification of Penicillia and Aspergilli isolated from Italian grana cheese

"Available online 18 January 2018"Penicillium and Aspergillus genera, both including mycotoxin producing species, were reported as associated to cheese and cheese working environment, but never studied in an extensive way in Italian grana cheese (Grana Padano and Parmigiano Reggiano). The aim of this work was to address the identification of Aspergilli and Penicillia associated to grana cheese in order to lay down the basis for risk assessment and safe processing for a high quality production. One hundred and four strains belonging to Aspergillus and Penicillium genera were obtained from cheese crust and from ripening room air (with the latter largely dominant), and identified following a polyphasic approach, strongly required for the identification at the species level. Morphological observation was used along with molecular techniques, RAPD-PCR fingerprinting and calmodulin gene sequencing (CaM), the former aimed to limit as much as possible the latter sequencing effort. Seventy four percent of the strains were assigned to Penicillium subgenus Penicillium, section Fasciculata. Main mycotoxin producing species identified were A. flavus, P. crustosum and P. verrucosum, while the dominant species in both air and cheese crust was P. solitum, which has never been so far reported as mycotoxigenic. Results obtained in this study confirmed that mycotoxin contamination is a possible issue to face during grana cheese making.The present work was supported by the following institutions: Consorzio del Formaggio Parmigiano Reggiano, Consorzio per la tutela del Formaggio Grana Padano, Fondazione Romeo ed Enrica Invernizzi, the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/ 2013 unit and COMPETE 2020 (POCI-01-0145-FEDER-006684) and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte. Simone Decontardi carried out this work within the PhD school “Agrisystem” of the Universita Cattolica del Sacro Cuore (Italy).info:eu-repo/semantics/publishedVersio

Low Water Activity Induces the Production of Bioactive Metabolites in Halophilic and Halotolerant Fungi

The aim of the present study was to investigate indigenous fungal communities isolated from extreme environments (hypersaline waters of solar salterns and subglacial ice), for the production of metabolic compounds with selected biological activities: hemolysis, antibacterial, and acetylcholinesterase inhibition. In their natural habitats, the selected fungi are exposed to environmental extremes, and therefore the production of bioactive metabolites was tested under both standard growth conditions for mesophilic microorganisms, and at high NaCl and sugar concentrations and low growth temperatures. The results indicate that selected halotolerant and halophilic species synthesize specific bioactive metabolites under conditions that represent stress for non-adapted species. Furthermore, adaptation at the level of the chemical nature of the solute lowering the water activity of the medium was observed. Increased salt concentrations resulted in higher hemolytic activity, particularly within species dominating the salterns. The appearance of antibacterial potential under stress conditions was seen in the similar pattern of fungal species as for hemolysis. The active extracts exclusively affected the growth of the Gram-positive bacterium tested, Bacillus subtilis. None of the extracts tested showed inhibition of acetylcholinesterase activity

Methyl cellulose/cellulose nanocrystal nanocomposite fibers with high ductility

Methylcellulose/cellulose nanocrystal (MC/CNC) nanocomposite fibers showing high ductility and high modulus of toughness were prepared by a simple aqueous wet-spinning from corresponding nanocomposite hydrogels into ethanol coagulation bath followed by drying. The hydrogel MC aq. concentration was maintained at 1 wt-% while the CNC aq. loading was systematically varied in the range 0 – 3 wt-%. This approach resulted in MC/CNC fiber compositions from 25/75 wt-%/wt-% to 95/5 wt-%/wt-%. The optimal mechanical properties were achieved with the MC/CNC composition of 80/20 wt-%/wt-% allowing high strain (36.1 %) and modulus of toughness (48.3 MJ/m3), still keeping a high strength (190 MPa). Further, we demonstrate that the continuous spinning of MC/CNC fibers is potentially possible. The results indicate possibilities to spin MC-based highly ductile composite fibers from environmentally benign aqueous solvents.Peer reviewe