L M Khomich’s scientific contributions

Juices from fruits and vegetables show a complex composition, they contain several hundred different substances. In addition to water and common metabolites such as carbohydrates, juices contain organic acids, minerals and trace elements, vitamins, polyphenolic and other biologically active compounds. Moreover, each type of juice is characterized by a unique set of natural compounds and is able to contribute to providing the human body with micronutrients. The study and analysis of the nutrient composition of commercially produced juices, which are currently the most consumed by the population, contributes to understanding the place of juices in healthy nutrition and is intended to contribute to the development of relevant recommendations for their use. The purpose of the research was to evaluate their nutritional density and nutritional value based on the analysis of published data on the nutrient composition of juices, and then offer recommendations on the use of juices in healthy nutrition. Material and methods. The analysis of nutrient profiles of ten popular types of juices presented on the market of the Russian Federation (apple, orange, grapefruit, grape, tomato, pomegranate, pineapple, carrot, cherry, peach) was carried out. Nutritional density indices (NDI) were calculated as the degree of satisfaction of a person's need for a particular nutrient when filling the calorie value of the diet (2500 kcal) only with this product. The integral score characterizing the degree of the juice compliance with an optimally balanced daily diet, taking into account the energy content, which provides 5% of energy, was also calculated. Results. NDI and the integral score of various types of juices show that juices have a high nutritional value and can make a significant contribution to the intake of some nutrients and bioactive compounds. The most important substances from juices are polyphenolic compounds (flavonoids, phenolic acids) and carotenoids (β-carotene, lycopene). All juices also contain significant level of potassium and magnesium, and they can serve a source of some vitamins and minerals (depending on the individual nutrient profile): citrus juices are the source of vitamin C and folates, pineapple - of manganese, vitamin C and B vitamins, apple - chromium, grape - molybdenum, iron and chromium, pomegranate - copper and tannins, cherry - iron, copper and pantothenic acid; vegetable juices, such as tomato and carrot juices, contain a wide range of essential micronutrients. Juices with pulp and juices without clarification can be a source of pectins and dietary fiber. Modeling of juice rotation in the diet shows that in this case, 75% of the nutrients (from 32 studied) will have a NDI1, i.e. provide a meaningful intake with juice. Conclusion. The characteristic features for each type of juice regarding the content of vitamins, minerals and other biologically active compounds should be taken into account to assess the place of juices in healthy nutrition and develop modern recommendations for their consumption. Such recommendations include alternating different types of juices in the diet, as well as, if necessary, the choice of certain juices to include in the diet, depending on the individual's nutritional needs.

Carrot juice is one of the main products of carrot processing and the second most popular vegetable juice after tomato. Due to the presence of a complex of various nutritive and biologically active substances (BAS) carrot juice can make a significant contribution to maintaining human healthy diet. The aim of the study was to establish the nutrient profile of carrot juice. Material and methods: A study of parameters of carrot juice of industrial production, characterizing its nutritional and biological value was carried out. The results of these experiments were compared with the data of BAS profiles of carrot juice from reference books and scientific publications. Results and discussion: The established nutrient profile includes data about content of more than 30 nutritients and BAS. The sucrose is the predominant carbohydrate in carrot juice; glucose and fructose concentrations are substantially lower. Among organic acids predominates L-malic acid whereas content of citric acid is usually 5-10 fold lower than that of L-malic acid. The total acidity of carrot juice is low, on average 0.25 mg of organic acids is present in 100 cm3 of juice. Carrot juice is a relatively rich source of a number of vitamins and minerals. A serving (200-250 cm3) of industrial carrot juice on average contains around 18% of the recommended daily intake (RDI) for potassium, 9% for magnesium, 8% for iron, 12% for copper and 14% for manganese. Vitamins are represented to a large extent by β-carotene and other carotenoids (more than 400% of the RDI in a serving), as well as niacin, biotin and pantothenic acid - about 7% of the RDI in a serving for each of these vitamins. The content of vitamins E and K in serving averages 17 and 10% of the RDI respectively. Not clarified carrot juice contains about 1.1 g of dietary fiber in 100 cm3, including pectins - about 0.2 g/100 cm3. Conclusion: Based on the results of this investigation the carrot juice might be considered as a substantial source of minor BAS mostly carotenoids, vitamins E and K, group B vitamins: niacin, biotin, pantothenic acid, mineral substances: potassium, magnesium, iron, copper, manganese, as well as dietary fiber.

Peach fruits (Prunus persica L.) contain a complex of nutritive and biologically active substances. The extraction of juice from peaches is relatively difficult due to the high content of fruit pulp so for the purposes of the juice industry, most peaches are processed in puree which is the basis for the production of peach juice products. Data on the nutrient content in peach juices-purees are few and require clarification and addition as applied to industrial products. The aim of the study was to investigate and update the composition of main nutrients of peach juice-puree. Material and methods. The nutrient composition of peach juice products of industrial production has been studied. Analysis of the results obtained in conjunction with the analysis of the data of reference books and scientific publications regarding peach fruits and juices-purees from them has been performed. Results and discussion. Nutrient profile of peach juice-puree has been established. The nutrient profile shows the content of more than 30 nutritive and biologically active substances. The prevailing saccharide in peach juice-puree is sucrose; glucose and fructose are present in lower concentrations. In addition to sugars, peach juice-puree contains sorbitol - about 0.4 g per 100 g. The total acidity of peach juice-puree is low, in 100 g there is an average of 0.5 g of organic acids, most of which are L-malic and citric acids. Regarding the polyphenols of peach juice-puree, the most significant are hydroxycinnamic acids, mostly chlorogenic, at the concentration of about 10 mg/100 g. The main type of peach juice products on the market are peach nectars containing 40-50% of juicepuree. Peach nectar is rich in vitamin E - more than 20% of the daily requirement per serving, dietary fiber (15% of the daily requirement for pectins and 5% of total dietary fibers), and the content of hydroxycinnamic acids in it fully satisfies or exceeds the adequate daily intake. A serving of peach nectar also contains on average 7% of daily requirement for β-carotene, 8% in copper, 6% in potassium. Conclusion. The most significant micronutrient and minor biologically active substances for peach juice products are dietary fibers, hydroxycinnamic (chlorogenic) acids, β-carotene, vitamin E, and potassium and copper.

Pomegranate juice is one of the main products of pomegranate processing with high content of a complex of polyphenolic compounds. It possesses high antioxidant activity. The aim of the study is to establish the nutritional profile of pomegranate juice. Material and methods. A research of nutrient composition of commercial pomegranate juice and analysis of the results in conjunction with the data of chemical composition present in reference books and scientific publications have been carried out. Results and discussion. The nutrient profile of pomegranate juice has been defined. The nutrient profile shows the content of more than 30 nutrients and biologically active substances. Sugars of pomegranate juice are represented by glucose and fructose in approximately equal concentrations. Citric and L-malic acids prevail of the organic acids in pomegranate juice while the content of citric acid, as a rule, is several times higher than the content of L-malic. The total acidity of pomegranate juice is high, on average 1.1 g of organic acids is present in 100 cm3 of juice. A portion of pomegranate juice of industrial production on average contains 15% of the recommended daily allowance of potassium, 5% of magnesium, about 10% of copper. Pomegranate juice is rich in polyphenolic compounds - flavonoids and phenolic acids, as well as tannins, which are mainly represented by ellagotannins. The content of anthocyanins in pomegranate juice of industrial production on averages is 1 mg/100 cm3 (the majority is cyanidin-3,5-O-diglucoside - about 40% of the total content of anthocyanins), ellagic acid - on average 4 mg/100 cm3. The total concentration ellagotannins ( mostly punicalin and punicalagin ) is on average 40 mg/100 cm3. Conclusion. Polyphenolic compounds (ellagotanins, anthocyanins, ellagic acid) and minerals - potassium, magnesium, copper are the most significant for pomegranate juice from the point of view of providing human body with micronutrients and minor biologically active substances.

Everyjuice contains a unique set of nutritive and biologically active substances, exhibiting the properties of the named fruit or vegetable. To characterize the nutritional profile of tomato juice, the literature data (including official reference books) and the results of studies of domestic industrially produced tomato juices conducted by the Russian Juice Producers Union (RSPS) and its members have been analyzed and summarized. From the point of view of providing a man with micronutrients and minor biologically active substances, tomato juice is a significant source of antioxidants-carotenoids and Vitamin E, as well as several minerals and trace elements. The amount of lycopene in a glass of tomato juice (200-250 ml) completely satisfies or exceeds the recommended daily intake of this carotenoid; the level of β-carotene in the same volume ofjuice provides about 20% of the recommended daily intake of Vitamin A; potassium and copper-12-15%, magnesium, iron, manganese and phosphorus-about 5%. Tomato juice is a source of dietary fiber, including soluble dietary fiber (pectin). A glass of tomato juice contains about 12% of the recommended daily intake of pectins and about 8% of dietary fiber. Wherein the calorie content of tomato juice is low-an average of 19 kcal/100 ml. The article continues a series of publications on juices nutrient profiles.

Based on the published data on the content of nutritive (NS) and biologically active substances (BAS) and the results of studies of various samples of domestic industrial grapefruit juice, the article presents the nutrient prof He of grapefruit juice containing data about more than 30 NS and BAS. Grapefruit juice is one of the relatively low-calorie fruit juices - 100 ml of grapefruit juice contains an average of 39 kcal. Like other citrus juices, it is rich in organic acids, the main of which is citric acid (0.8-2 g/100 ml). Potassium, magnesium, Vitamin C, as well as flavonoids (mostly narigin) are the most significant for the estimation of nutritional and biological value of grapefruit juice of industrial production. A glass of grapefruit juice contains, on average, about 10% of the daily requirement in potassium, 6% - in magnesium and about 100% - in Vitamin C. The amount of flavonoids in a glass of grapefruit juice provides up to 60% of the adequate daily intake. Conducted studies of fresh grapefruits purchased in the trade network show that the content of potassium, magnesium and Vitamin C in grapefruit juice of industrial production is comparable to the content of these micronutrients in fresh fruits.

Russia is one of the main producers of sour cherry, along with Turkey and Poland, and juice products from sour cherry are widely represented in the trade network. Sour cherry, contains practically no sucrose, has a high content of organic acids, is rich in mineral and polyphenolic compounds, in particular, in anthocyanins, which give it a bright color. Sour cherry is close to many berries by its composition. At the same time, the literature data on the content of various natural substances in sour cherry juice are not numerous and need to be clarified, especially with reference to the industrially produced juice products. Organic acids of sour cherry juice are represented mainly by L-malic acid (1.2-2.7 g/100 ml). The most significant substances of sour cherry juice are polyphenolic compounds - flavonoids, mainly represented by anthocyanins (about 70% of them is cyanidin-3-O-glucosylrutinoside); phenolic acids - hydroxycinnamic acids, mainly represented by chlorogenic acids and 3-coumaroylquinic acid, as well as mineral substances - potassium, magnesium, copper and manganese. Sour cherry juice has a high acidity and is usually consumed in the form of nectars. Flavonoids content in a portion of sour cherry nectar is about 15% of adequate daily intake, anthocyanins - 20%, and the content of hydroxycinnamic acids - exceeds it. One portion of nectar contains on the average 10% of the daily requirement of the human body in copper and manganese, 6% in potassium and 3% in magnesium.

Fruits and vegetables are an important component of proper nutrition, but its consumption in Russia is below the recommended levels, and fruit and vegetable juices can partially fill the lack of fruits and vegetables in the diet. Russian Union of Juice Producers (RSPS) has been accumulating data on nutritive and biologically active substances of juices during five years to assess the contribution of juices to the diet. RSPS has organized research in accredited laboratories of more than 500 samples of reconstituted and direct juices available on the shelves of Russian stores since 2010 with the aim to specify and supplement the data listed in the various reference books. Analysis of literature data on the content of nutritive and biologically active substances is performed in the article together with the results of studies of various samples of apple juice of domestic industrial production. The nutrient profile of apple juice is given on this basis and contains 30 nutritive and biologically active substances. The most significant from the point of view of providing human body with micronutrients and minor biologically active substances for apple juice of industrial production are Potassium, Chromium and hydroxycinnamic (mostly chlorogenic) acids. A glass of apple juice (250 ml) contains, on average, about 8% of the daily requirement for potassium, 12.5% for chromium and about 150% of adequate daily intake of hydroxycinnamic acids. Additionally apple juices (except clarified ones) contain pectins-in a glass (250 ml) ofjuice on average there is 15% of daily requirement in pectins, and the total content of soluble and insoluble dietary fiber in apple juices with pulp on averages make 5% of daily human requirement in a dietary fiber.