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CNAA / Theses / 2018 / July /

Biochemical and technological changes of walnuts during processing and storage,PhD thesis in technology

Author: Boaghi Eugenia
Degree:doctor of engineering
Speciality: 05.18.01 - Technology of food products (with specification of products and procedures)
Scientific adviser: Vladislav Reşitca
doctor, associate professor (docent)
Institution: Technical University of Moldova


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


Adobe PDF document1.61 Mb / in romanian


CZU 634.51.65

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walnuts, processing, sorption, oxidation, respiration, bleaching, walnut milk.


Field of study: 253.01 – Technology of plant origin products (Technology of catering products).

The purpose of the work: Quantification of quality parameters (physical, chemical and physico-chemical) and their evolution in storage period depending on the changes in the biochemical, physico-chemical and technological properties of the walnut fruit.

Objectives:Studying the intensity of the biological oxido-reduction process (respiratin process) of walnuts during storage; Research on the impact of moisture and water activity on the hygroscopic properties of walnuts; Appreciation of effective ways and methods for improving the quality of walnuts at primary processing.

Scientific novelty consists in the multi-spectral analysis of the biochemical changes of the walnuts during storage and those that follow the technological treatments. It was experimentally proved the particularities of the walnut respiration process by involving the fatty acids Krebs in cycle as main sources of energy.It has been shown that humidity sorption processes in relatively small amounts predominantly influence the oxidation reactions of polyunsaturated fatty acids in the walnut core texture.

Important scientific problemsolved consists in the scientific identification and argumentation of some new technological processes of walnuts treatment (pericarp etching with ethephon and hellwhitening with oxidizing agents), which had the effect of improving their quality (the degree of the pericarp dehiscence and the shell color) and which allowed the upgrading of the post-harvest handling scheme of the nuts into the shell.

Theoretical significance.There have been obtained scientific results demonstrating the possibility of monitoring and conducting biochemical changes duringwalnut storage and chromatic parameters that influence the commercial aspect of walnuts in the shell.

The applicative valueconsistsin the elaboration and optimization of the decay process of pericarp and whitening of walnut shells and technological developments for walnut kernel processing with the production of new O/W emulsion products.

Implementation of scientific results. The results obtained are reflected in the institutional project reports no. 15.817.02.30A "Methodological and technical elaboration for the modernization of the walnut processing technology (Juglans regia L.) with the use of biologically active components in functional food" "NUCALIM-PROBIO", strategic direction 50.07 and a patent application Whitening the walnuts.