site.btaCryobiologist Tsvetan Tsvetkov: Designer of the Bulgarian Space Menu
Academician Tsvetan Tsvetkov (1943-2022) takes credit for the design of the Bulgarian space menu, which was developed for the first and second Soviet-Bulgarian space missions implementing the Shipka Research Project under the Intercosmos Programme, Prof. Dr Iliana Nacheva, Director of the Institute of Cryobiology and Food Technology, told BTA.
The first Bulgarian space menu consisted of more than 50 types of freeze-dried foods: yoghurt, nuts, strawberries, apples, apricots, peaches, melon, moussaka, bean soup and other meals. Their composition and energy content were geared to the extreme working and living conditions of cosmonauts during space flight.
The space foods were available during the two space flights with Bulgarian participation as full daily menus, in complete tablet form with a minimum mass and volume 250-350 grams. These research achievements have ranked Bulgaria third in the world after the US and Russia as space food producing countries.
The Bulgarian menu is intended for a daily course of two breakfasts, lunch and dinner. These foods meet the needs of the human body for biological nutrients. The Tsvetkov team holds two patents for the development of freeze-dried products.
Freeze-dried fruits and vegetables are characterized by minimum moisture, high carbohydrate content, vitamins, mineral salts, a maximum preserved enzyme system, flavour complex, and high microbial purity.
Space food is increasingly expanding its reach. It is now also used by participants in expeditions to Antarctica and the Himalayas.
Tsvetkov's overall scientific and inventive pursuits marked a breakthrough in cryobiology and cryobiotechnology, interdisciplinary fields that are extremely important for agriculture, food processing, medicine and pharmacy. His contributions in the cryopreservation of tissue transplants, model and natural biomembranes and cell organelles are achievements on a global scale. He developed unique technologies for lyophilized space foods. Tsvetkov has 42 inventions and 37 patents in his name. On April 26, 2004 he was inscribed in the Golden Book of Inventors at the Patent Office of the Republic of Bulgaria.
In 1979 he defended his doctoral thesis, earning the academic degree of Doctor of Technical Sciences. As from 1987 he was a full professor at the Higher Institute of Food Industry in Plovdiv (South Central Bulgaria). He also taught in the Master of Biotechnologists programme of the Sofia University Faculty of Biology and at the Technical University of Sofia. He was elected corresponding member of the Bulgarian Academy of Sciences in 1989 and academician in 1994. He founded and directed the Institute of Cryobiology and Food Technology at the National Centre for Agricultural Sciences of the Agricultural Academy.
Tsvetkov's scientific achievements are documented in over 250 research papers, of which 35 present his original fundamental research contributions published in the American journal CRYOBIOLOGY, and 75 were reported at international congresses and symposia. He published 15 monographs, 14 books, textbooks, reference books, reviews and brochures. Tsvetkov is holder and co-holder of about 60 implemented rationalizations, author's certificates and patents in cryogenic processes and freeze drying.
In 1973 he was admitted as a member of the International Institute of Refrigeration in Paris, where he was Vice President of the Cryobiology and Lyophilization Committee. As from 1977, he represented Bulgaria in the US-based International Society of Cryobiology, the American Association of Tissue Banks (AATB), the International Confederation for Thermal Analysis and Calorimetry (ICTAS), and the Japanese Society for Low Temperature Medicine. Tsvetkov was a long-standing member of the Editorial Board of the journal CRYOBIOLOGY.
Developments Put to Practice
Tsvetkov developed biotechnologies for food preservation and drying in vacuum. Under his guidance, lyophilized foods on various bases and functional foods for nutrition under extreme conditions, obtained by modern cryobiotechnological methods, were developed and implemented. Technologies for preparation and storage of various lyophilized biopreparations for wound healing and materials for biotransplantation were designed as well.
Tsvetkov's research effort contributed to identify the factors affecting the cultivation, cryoprotection, freeze-drying, long-term storage and rehydration of selected strains of Bulgarian cultures: Lactobacillus bulgaricus and Streptococcus thermophylus.
Over 60 types of freeze-dried functional foods were also developed to improve human health status, including a series of freeze-dried biostimulants designed for athletes, for healthy and sick people.
Analyses and concepts were evolved in order to intensify and optimize processes, machinery and equipment in cryobiology and lyophilization and to set up automated assembly lines for the needs of agriculture and the food industry.
Cryobiological terminology was proposed as one of the first attempts to systematize and standardize the terms and concepts in this new scientific field. It is of great theoretical and practical significance for its future development.
Optimal technological parameters for low-temperature treatment of probiotics were developed on the basis of effective means of putting biological systems into a state of deep-stem anabiosis.
Original combined technologies based on freeze-drying and radiation irradiation (cold sterilization) were devised, experimented and implemented for long-term, high-quality and safe preservation and storage of various types of fruits, meat and perishable meat products in order to extend their shelf life while keeping their consumer value to the greatest extent.
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This article was written within the framework of a partnership initiative between BTA and the Bulgarian Patent Office (BPO) which envisages the presentation of Bulgarians listed in the Golden Book of BPO and the activities of the BPO in a joint weekly column entitled "Created in Bulgaria".