IntroductionThe Russian Arctic occupies about 70% of theRussian Federation. It is an important and developingsource of natural resources. It accounts for 90% of coalreserves, 80% of hydropower resources, large strategicreserves of oil and gas, almost the entire volume ofexplored rare metals and diamonds, 50% of iron oredeposits, 80% of forest resources, and more than 60%of fresh water reserves [1, 2]. Intensive development ofnatural resources attracts a lot of shift workers. However,the harsh climatic conditions make it difficult for thetemporary residents to live and work in the RussianArctic: rapid temperature changes, extreme light regime,and various geomagnetic, gravitational, and radiationanomalies [3–7]. Moreover, such conditions are quiteoften accompanied by unfavorable social and industrialenvironment. Together with information overloads,it causes additional mental fatigue and emotionalstress in the migrant workers, which can becomechronic [3, 8–12].In October 2020, Russian President Vladimir Putinsigned the Strategy for the Development of the RussianArctic and Ensuring National Security for the period until2035. The pressing issue makes it extremely relevant toimprove the adaptation of shift workers and strengthentheir health. First of all, shift workers need access toadequate nutrition [6, 8, 9, 13–15]. Second, they shouldbe provided with functional and preventive foods tomaintain health, restore energy costs, reduce the loss ofworking time, and increase performance [16–18].The research objective was to collect and processscientific and technical data on the food patterns ofcommunities that experience constant physical exertionunder harsh climatic conditions and to prove the prospectsfor introducing freeze-dried long-storage products intolocal diets.Study objects and methodsThe paper introduces a review of domestic and foreignscientific publications in two major fields: nutrition anddiet of the residents of the Far North and the developmentof freeze-dried products for long-term storage in extremeconditions.Results and discussionDiets and food patterns of Arctic communitiesoften become focus of scientific attention. As a rule,research objective is to calculate deviations from therecommended nutrient intake [19, 20].Ionova studied the diet of the shift workers in theYamal-Nenets Autonomous Region and revealed ahighly atherogenic character of their diet: more thanАннотация.Введение. В статье собраны сведения об особенностях питания населения, работающего вахтовым методом в условияхКрайнего Севера. Цель работы – сбор и анализ научно-технической информации о структуре питания временно работающегоприезжего населения в российских регионах с трудными климатическими условиями, а также перспективах использованиясухих сублимированных продуктов с функциональными свойствами в условиях повышенных физических нагрузок.Объекты и методы исследования. Научные публикации, посвященные вопросам питания и рациона населения,проживающего в условиях Крайнего Севера, а также разработки сублимированных продуктов длительного хранения вэкстремальных условиях.Результаты и их обсуждение. Выявлено, что рацион вахтовиков характеризуется повышенным содержанием жировыхи углеводных продуктов, при недостатке полноценного белка, витаминов и минеральных веществ. В рационах отмеченонедостаточное количество молока и молочных продуктов, свежих фруктов и овощей, и повышенное содержание сахара икондитерских изделий, что отрицательно влияет на здоровье населения и приводит к развитию наиболее распространенныхалиментарно-зависимых хронических неинфекционных заболеваний. Показано, что рацион должен соответствоватьособенностям обмена веществ при хроническом стрессе и быть полноценным не только по количественному содержаниюкомпонентов, но и по качественному. Определено, что отсутствие необходимых продуктов связано со сложностямиих доставки в регион, что приводит к микробиологической и химической контаминации пищевых продуктов во всехадминистративных территориях Арктической зоны. В связи с чем, возникает необходимость в специализированныхпродуктах высокого качества с длительными сроками хранения.Выводы. Предложено расширение ассортимента и улучшение структуры питания путём использования в рационахсублимированных функциональных продуктов. Дана информация по примерам использования сублимированных продуктовв нашей стране и за рубежом в условиях повышенных нагрузок в питании космонавтов, военнослужащих, спортсменови др. Показана экономическая эффективность применения сублимированных продуктов питания в зависимости отпродолжительности хранения и дальности перевозки, по сравнению с холодильным хранением. Обобщены данные оперспективах метода вакуумной сублимационной сушки для создания специализированных сублимированных продуктов.Ключевые слова. Питание, рацион, сублимированные продукты питания, функциональные продукты, стресс, адаптация,макронутриенты, микронутриенты, Крайний СеверДля цитирования: Freeze-Dried Food in the Diet of Temporary Residents of the Far North / E. I. Titov, I. S. Krasnova,V. I. Ganina [et al.] // Food Processing: Techniques and Technology. – 2021. – Vol. 51, № 1. – P. 170–178. https://doi.org/10.21603/2074-9414-2021-1-170-178.172Titov E.I. et al. Food Processing: Techniques and Technology, 2021, vol. 51, no. 1, pp. 170–17825% of the temporary residents demonstrated excessfat consumption [20]. Epidemiological studies on theterritory of the Yamalo-Nenets Autonomous Regionshowed that local shift workers aged 20–59 wereprone to metabolic syndrome. Their actual diet wasimbalanced in many aspects as it contained too muchcommon fats, cholesterol, and sodium, while lacking ω-3polyunsaturated fatty acids, carbohydrates dietary fiber,vitamins, and minerals, e.g. B-group vitamins, potassium,calcium, magnesium, phosphorus, etc. [19, 21, 22].At a mine in the North-Yenisei region of theKrasnoyarsk Territory, the food in the stationary canteenfully met the requirements for proteins. In fact, the localshift workers received more protein than recommendedfor the daily intake, because they habitually chosemeat or fish for lunch and dinner, while their breakfastconsisted mostly of boiled eggs, cheese, sausages, andcottage cheese with sour cream. However, the FederalResearch Center for Nutrition and Biotechnology warnsthat protein assimilation can fall down to 80%, whichjustifies the increased protein intake. The diet satisfiedthe physiological need for fats by 100% and for digestiblecarbohydrates – by 85.3%. The content of dietary fiber inthe daily ration exceeded the norm by two times becausevegetable salads, bean puree, cereals, bread, etc. were themost popular and affordable dishes for breakfast or as aside dish. The miners’ diet proved to be quite complete,varied, and balanced. However, the distribution ofcalories by meals was imbalanced, and the diet was poorin vitamin C, calcium, and magnesium [8].In the Norilsk industrial region, miners’ diet appearedlacking in calories and essential micronutrients. The dietrevealed a significant shortage of dairy products, freshvegetables, and fruits. The share of fish, seafood, eggs,and vegetable oil was below the recommended level,while that of sugar and confectionery products exceededthe norm [23].A research on the food patterns and nutritional statusof industrial workers in the Sverdlovsk region showed anexcessive intake of fats, saturated fatty acids, and monoanddisaccharides, as well as a lack of polyunsaturatedfatty acids and dietary fiber [24].Since the 1990s, the Federal Service of StateStatistics for the Republic of Sakha (Yakutia) hasregistered a downward trend in the annual production andconsumption of many foods per household member. Fordairy products, this amount has fallen from 437 to 279 kg;vegetables and melons – from 82 to 62 kg; eggs – from269 to 176 pcs. By 2012, the share of agriculturalproducts produced in Yakutia was 28% of the norm formeat products, 73% – for dairy products, 66% – for eggs,and 46% – for vegetables and melons. These data indicatethat the local food pattern is undergoing a transformationas the share of carbohydrates and fats increases due to thedecreasing protein intake [25].The Federal Research Center for Nutrition andBiotechnology studied the food patterns of the indigenousand migrant communities of the Russian Arctic.Compared to the indigenous people, the newcomersappeared to consume less bakery products, fatty products,and fish while eating more vegetables, dairy products(kefir, fermented baked milk, yogurt, sour clotted milk,cheese, cottage cheese, sour cream, etc.), and – lessoften – such canned dairy products as sweet condensedmilk [26]. In general, the local level of consumptionof dairy products is not high enough. For instance, inthe Tyumen region, only 45.5% of surveyed residentsconsume dairy products every day. The insufficientcalcium intake is typical of all age groups [27].In 2014, the level of self-sufficiency for milk inaccordance with the recommended rational consumptionrates was 9.3% in the Murmansk Region and 0.5% in theChukotka Autonomous Region [13]. A similar study for2013 also confirmed that the level of self-sufficiency forcertain foods was lower than the recommended nutritionalstandards. For milk, it ranged from 0.6 in the ChukotkaAutonomous Region to 59% in the Republic of Sakha(Yakutia); for meat – from 4 in the Magadan Region to34.3% in Chukotka and Yakutia; for eggs – from 21.7 inChukotka to 69.5% in the Murmansk Region [28].Scientists believe that introducing functional andlocally produced foods into the local diet can increasepeople’s resistance to unfavorable environmental andlabor conditions [8, 13, 29–31]. However, there isevidence that European settlers who adjusted to the localproducts and food patterns of the indigenous populationdeveloped negative changes in lipid metabolism laterin life. Their metabolism shifted from the carbohydratetype to the fatty type, and it is fats that compensate forincreased energy consumption, which increases serumcholesterol and atherogenic lipids in peripheral blood,thus triggering atherosclerosis [32].Panin et al. performed a longitudinal study, whichresulted in the principle of adequacy of nutrition to thestate of energy metabolism. The obtained results made itpossible to reconsider the nutritional standards for shiftworkers in order to adjust them to the adaptive changesin their metabolism. The research team developedcarbohydrate, basic, and protein-lipid diets for youngmale shift workers and tested them under real-lifeconditions in the Far North. Both the carbohydratediet and the diet of the indigenous population provedinadequate for the migrant working population. Theideal of proteins:fats:carbohydrates ratio was 16:40:44.However, energy value can vary depending on theseverity of labor [33].Available publications demonstrate that the diet oftemporary residents of the Far North should correspondto the metabolic profile typical of people in chronicenvironment stress and be complete both quantitativelyand qualitatively [8, 19, 29, 31, 34]. Most studies on thediet of non-indigenous communities register excessiveconsumption of carbohydrates, refined sugars, and173Титов Е. И. [и др.] Техника и технология пищевых производств. 2021. Т. 51. № 1 С. 170–178saturated fatty acids against the deficiency of vitamins,some minerals, essential proteins, and amino acids.If combined with low ambient temperatures andinsufficient calorie intake, even a short-term physicalactivity can lead to vitamin C deficiency. Lowtemperatures are known to affect the metabolism ofvitamin C and B-group vitamins [6, 35, 36]. Moreover,vitamin D deficiency is quite common in high latitudes[37, 38]. These factors trigger the development of suchalimentary chronic non-infectious conditions as obesity,atherosclerosis, cardio-vascular problems, arterialhypertension, diabetes, vitamin deficiency, etc. [20, 22,26, 34, 39, 40].Fresh vegetables, fruits, berries, as well as eggs anddairy products, are hard to find in the Russian Arctic. It isconnected with the existing microbiological and chemicalcontamination of food products in all administrativeterritories of the Arctic zone [13, 14]. Nowadays, themicrobiological indicators of milk, fermented dairyproducts, meat, poultry, fish, and seafood seldom meetsanitary and epidemiological standards [14].This situation results from the economic difficultiesassociated with the food supply to these remote territories[8, 14, 40, 41, 42]. The most cost-effective and popularway of food delivery is first by railroad and then by rivertransport. Other options are the Northern Sea Route andair transport.The food delivery scheme to the Republic of Sakha(Yakutia) shows that the shipping cost for perishablefood by rail and river transport is 82 rubles (30 days), bythe Northern Sea Route – 118 rubles (13–20 days), by air– 283 rubles (7 h). All these deadlines are hard to meet inthe harsh climate, and delivery period often exceeds shelflife of such perishable goods as dairy products, freshfruits and vegetables, etc. [2].Such conditions require new long-storage foodproducts with a low weight and volume, which can beachieved by lowering the final moisture content andusing vacuum packaging. For instance, Filippova et al.developed a technology for natural cryogenic productsto be used in extreme living conditions. The team groundraw materials at cryogenic temperatures and then driedthem at moderate temperatures. The experiment involvedcontract servicemen (n = 30 in each observation) thatperformed extreme physical activities. Introducing 30 gof the experimental product per day for 15 days had apositive effect on their morphological and functionalcondition. The scientists reported reliable data on thepositive changes in the respiratory, cardiovascular, andcentral nervous systems [43].The modified diet had a beneficial effect on lipidand protein metabolism as well as liver function. 46.7%of the test subjects improved the muscle strength of thedominant hand. The share of soldiers with excellentphysique increased by 1.6 times, the number of thosewith good physical adaptation – by 1.4 times. Thenumber of test subjects whose defense mechanismsimproved their adaptive potential increased by 1.5 times.The new product was also tested on a group of conscriptservicemen with weight deficit (n = 650), who consumedup to 35 g per day for 15 days. The new diet helped themto restore standard body weight in 75% of cases. Afterthe experiment was repeated, 99% of the test subjectsreached standard body weight [43].Freeze-dried food products are another promisingdirection in improving the diets of temporarily residentsof the Arctic regions. Such products are obtained byvacuum freeze drying, which increases shelf life whilepreserving the nutritional value. The method can beapplied to a wide range of food products, especiallyvegetables and fruits, but also dairy and meat products.Domestic freeze-dried products often proved invaluablein harsh conditions. For instance, freeze-dried meat andcottage cheese were in the diet of the famous Arcticexpeditions organized by The Komsomolskaya Pravdain the summer of 1973–1974 in order to find traces ofRussian pioneers. The expeditions received wide mediacoverage. The freeze-dried products were developedby the All-Russian Research Institute of Canning andVegetable Drying. During the ascent to Everest in 1984,Russian climbers gave full marks to the freeze-driedproducts developed by Vladimir Voskoboinikov [44].In the early 1960s, the Moldavian Research Instituteof Food Industry developed and tested a wide range ofvegetable-based freeze-dried products, which wereregularly used in space flights. In the mid-1970s,the Research Institute of Food Concentrate Industryand Special Food Technology became the leadingorganization for the development of rations and foods forcosmonauts, borscht with meat being their first successfulfreeze-dried project.The contemporary list of space foods includes 300types of high-quality, reliable, long-storage productsdesigned for specific conditions of transportation andoperation [45, 46]. Another list of 100 commercialfoods ensures the diversity of space diet. These productspassed cold-and-hot control tests and were divided intotwo groups: those with limited shelf life (60 days) andthose with prolonged shelf life (12-15 months). The firstgroup includes pressed beluga caviar, adjika, horseradish,ketchup, and salami mini sausages, while the secondconsists of liver pate, canned fish, meat, vegetable andfruit, freeze-dried yoghurts, dry instant drinks, andchocolate.The ration of ISS crews includes the following freezedriedproducts:– beef-based soups, e.g. borscht, green cabbage soup,sauerkraut cabbage soup, pickle soup, potato soup, andsmoked borscht;– main courses, e.g. goulash, pork tenderloin, roast beefwith side dishes (cabbage, peas in milk sauce, mashedpotatoes, buckwheat porridge), pork with lecso, vegetablestew with meat, home-style beef, and pasta with meat;174Titov E.I. et al. Food Processing: Techniques and Technology, 2021, vol. 51, no. 1, pp. 170–178– canned meat, e.g. chopped pork with eggs, veal withvegetables, chicken with eggs, chicken with prunes,chicken omelet, etc., and commercial canned food,e.g. liver pate with dill or bacon; and– canned fish, e.g. five kinds of pike perch, five kinds ofsalmon, beluga, sturgeon, aspic sturgeon, bream in spicytomato-mustard sauce, etc.The diet also includes such complete protein productsas freeze-dried milk, cottage cheese with blackcurrantpuree, sea buckthorn puree, and freeze-dried nuts, aswell as canned processed cheeses. Freeze-dried productsinclude pea puree soup, Bulgarian beans, and cannedbeans in tomato sauce.Freeze-dried foods are also known to be part ofNASA rations [47]. In the early days of the US spaceprogram, space flights lasted from a few minutes to24 h and required no substantial meals. However,astronauts involved in project Mercury contributed to thedevelopment of space food. They tested the physiologyof chewing, drinking, and swallowing solid and liquidfood in microgravity. The first astronauts ate freeze-driedfoods from aluminum tubes. Those tubes caused manyproblems: it was like sucking in a beverage through astraw, except that the food was much thicker. Specialmaterials coated the inner surface of aluminum tubesbecause the metal could interact with acids found insuch products as applesauce and produce hydrogen gas.Aluminum tubes often weighed more than the food theycontained.Eventually, tubes gave way to lighter plasticcontainers. Scientists developed small-size solidfreeze-dried foods compressed into dehydrated piecesor cubes. The cubes were rehydrated with saliva whenchewing. Food crumbles floating in microgravity coulddamage equipment, or the astronaut could inhale them.That is why the cubes were coated in gelatin to reducecrumbling. Those products were vacuum-packed inseparate portioned containers made of transparent threelayerplastic foil, which prevented moisture ingress,preserved taste, and helped to avoid spoilage.More recent diets included freeze-dried grape andorange drinks, fruit cocktails, turkey chunks, applesauce,cream chicken soup, shrimp cocktail, beef stew, chickenwith rice, and turkey with gravy. The menu was repeatedevery four days. Each astronaut received 0.58 kg offreeze-dried food per day.Freeze-dried products are an important part ofNATO army rations, which proves its rationale. Forexample, individual LRP rations are used in to feedsmall, well-armed reconnaissance teams that patrol deepin enemy-held territory. Each package contains 40 bags,each of which provides one soldier with three meals.The food packet weighs 300 g, and its calorie contentis 1540 kcal [48–50].In addition, freeze-dried foods are used byprofessional athletes during outdoor competitions and arepart of emergency food reserves [51–53].Vacuum freeze drying includes freezing the productand removing moisture by sublimating ice crystals invacuum. The process requires low temperatures, whichpreserves all important characteristics and qualityindicators of the product [54]. High-quality freezedriedproducts – vegetables, fruits, fermented milkproducts, minced meat and fish – are important both asindependent food products and as part of existing rationsand formulations. This principle can improve the diet oftemporary residents of Arctic Russia, both shift workersand their families.At the production stage, freeze drying is moreexpensive than simple freezing. However, storage,transportation, and cooking of frozen products requiremore energy costs, which is confirmed by foreign anddomestic studies [55, 56].Russia has good prerequisites for increasing theshare of freeze-dried foods in the food patterns of Arcticcommunities. The city of Borovsk, Kaluga Region, boastsa freeze drying plant with 20 domestic freeze-dryingunits that produce 340 kg of raw materials per dryingcycle each. The plant delivers one hundred differentfood products of plant origin. The technologies meet thebest international standards. Freeze-dried products fromBorovsk are highly appreciated by Russian consumersand receive prizes at domestic and foreign exhibitions.Freeze drying is a prospective technology to be usedin the diet of shift workers in the Russian Arctic [54].Freeze-dried products have numerous advantages:– they preserve nutritional value, including biologicallyactive thermolabile components, i.e. vitamins, enzymes,amino acids, probiotic microorganisms, etc. [56, 57];– maintain excellent sensory properties, e.g. size, taste,color, smell, etc. [58–62];– are resistant to radiation;– have low moisture content, which makes it possibleto store them for up to two years in sealed packaging inunregulated temperature conditions, and they maintainhigh sanitary and hygienic parameters [63];– possess good porosity and high hygroscopicity; as aresult, they regain their initial state quite easily, and thepowders get totally dispersed during rehydration [64];– can acquire new consumer properties and increase theirnutritional value if rehydrated with various biologicalfluids, e.g. minced meat reconstituted with milk;– contribute to new technologies due to traditional andnon-traditional raw materials [65];– have low weight, which reduces transport costs [66].For example, the mass of vegetable-based freeze-driedproducts is ten times lower than that of correspondingfresh fruits and vegetables.The review shows that the contemporary diets of shiftworkers in the Far North have a lot of flaws. They containa lot of fats, fast-digesting carbohydrates, and sodium,but lack fermented dairy products, fruits, and vegetables.Functional foods with prolonged shelf life can improvethe situation.175Титов Е. И. [и др.] Техника и технология пищевых производств. 2021. Т. 51. № 1 С. 170–178ConclusionTheoretical and practical research in new technologiesof freeze-dried products for preventive dietary nutritionis especially important as it contributes to the extensivedevelopment of natural resources in the RussianArctic, which is fueled by the migration of able-bodiedpopulation from the central regions. Shift workers havetheir own food patterns which local food cannot satisfy.As a result, their diet is imbalanced and poor in variousmacro- and micronutrients. Industrial production offreeze-dried products could improve the diet of shiftworkers in the Far North and people in emergencysituations, e.g. they can be added to autonomous survivalkits. Freeze-dried products can increase the adaptivepotential and improve the health of shift workers in hardto-reach regions.ContributionE.I. Titov supervised the research. V.I. Ganinareviewed the available scientific publications on nutritionand diets of shift workers in various regions of the FarNorth. I.S. Krasnova reviewed articles on the experienceof using freeze-dried products for long-term storage inextreme conditions. E.G. Semenova was responsiblefor the section about alimentary non-infectious chronicdiseases and the deficiency of various macro- andmicroelements in the diet of temporary residents of theFar North.Conflict of interestsThe authors declare that there is no conflict ofinterests related to the publication of this article.