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CNAA / Theses / 2018 / July /

Technological regimes to ensure the antioxidant potential of some horticultural products during storage and processing

Author: Cristea Elena
Degree:doctor of engineering
Speciality: 05.18.01 - Technology of food products (with specification of products and procedures)
Scientific adviser: Rodica Sturza
doctor habilitat, professor, Technical University of Moldova
Institution: Technical University of Moldova


The thesis was presented on the 3 July, 2018
Approved by NCAA on the 23 November, 2018


Adobe PDF document0.60 Mb / in romanian


CZU 664.8.022.7(043.2)

Adobe PDF document 8.61 Mb / in romanian
226 pages


antioxidant potential, colour, plant extracts, CIELab, polyphenols.


The aim of the study:identifying the technological operational regimes to maintain the antioxidant potential and the colour of the hydroalcoholic extracts from grape marc and berries.

The study objectives include the determination of the concentration of various classes of biologically active compounds in horticultural extracts and the instrumental characterization of their colour; the research of the evolution of the antioxidant activity and colour parameters during heat treatments and storage at different temperatures and in different environments (pH, ionic strength); the research of the copigmentation with gallic and tannic acids; the research of the influence of the nanoincapsulation in β-lactoglobulin on the antioxidant activity of the grape marc extract; the research of the separation of different fractions of antioxidant compounds using colloidal microfoam.

The scientific novelty and originalityinclude establishing the correlations antioxidant activitycolour and antioxidant activity-polyphenol content in various horticultural extracts; identifying optimal thermal treatments and optimal environmental conditions (pH, ionic strength) to maintain the antioxidant activity and colour of different plant extracts; testing the stability of the extracts in the presence of mineral salts used in food systems i.e. CaCl2; NaCl and KNO3, which showed colour enhancement in the grape marc extract; researching the copigmentation with gallic and tannic acids in different plant extracts. New results on the encapsulation of grape marc extract in β-lactoglobulin were obtained and the separation of polyphenols from aronia extracts using colloidal microfoam was tested for the first time.

The main scientific problem solved in the study consists of the identification of the optimal technological conditions to ensure the stability of the antioxidant properties and colour of the horticultural plant extracts for their use in food industry.

Theoretical importance. The research results present data on the content of polyphenolic compounds with antioxidant properties in horticultural plant extracts from Moldova; the instrumental colour parameters and the antioxidant activity of the extracts were investigated depending on the environment, temperature, storage time. New data on correlations antioxidant activity-colour and antioxidant activity-polyphenol content was obtained. New hypothetical deductions on the interaction between grape marc anthocyanins and Ca2+ ions were formulated.

Practical importance. The optimal storage conditions and thermal regimes for the use of the grape marc and berry hydroalcoholic extracts in food systems maintaining their antioxidant properties and colour characteristics were identified and scientifically proven based on the experimental results.

The implementation of the scientific results was carried out by their application and further research within the bilateral project „The substitution of synthetic food additives with bioactive components extracted from natural renewable resources” and the AUF project „L’utilisation de techniques innovantes dans l’obtention des molecules biologiquement actives”.