Volume 49, Issue 1, 2019

The present research features a new biotechnological approach for complex processing of secondary cereal products. The approach makes it possible to obtain new functional foods and ingredients, such as carbohydrate-protein concentrate, dietary fiber concentrates, biologically active substances, polyphenols, and xylo-oligosaccharides. The complex biotechnology involves oat bran biotransformation and includes chemical, hydrothermal, and enzymatic methods of extraction, which allows manufacturers to obtain functional ingredients with antioxidant and prebiotic properties. The concentrates obtained as a result of the study contained a significant amount of protein, hydrolysis products of polysaccharides (glucose, maltodextrins), and free polyphenols. The experiment produced concentrates of biologically active substances containing xylo-oligosaccharides and phenolic compounds. The content of polyphenols was 67% of the total amount in oat bran, protein – 6.9%, carbohydrates – 80.7% xylo-oligosaccharides whith prebiotic properties 35.3%–71.5%, and ash 11.3%. The obtained data indicated a high antioxidant activity of polyphenol extracts. The differences in antioxidant activity between various methods of extraction are associated primarily with the completeness of extraction and the stability of the extracted phenolic compounds. Ultrasonic treatment proved beneficial for the extraction kinetics and the polyphenol yield at the initial stage, with an increase in antioxidant properties. As for the antioxidant activity of polyphenol concentrate during storage, the research did not reveal changes for 8 months at a temperature of 20 ± 1°C and a relative humidity of 70 ± 5%. The study of the growth dynamics of Lactobacillus acidophilus and Bifi obacterium bifi um in media containing xylo-oligosaccharide concentrate confirmed the presence of prebiotic properties and their selectivity. The accumulation of biomass of prebiotic cultures occurred faster with the use of nutrient media with the use of xylo-oligosaccharide concentrate and lactulose, as compared with milk. Thus, the research confirmed the feasibility of biotechnology for transforming oat bran into functional ingredients, which makes it possible to use them in new technological solutions for products with bifidogenic properties.

The use of infusions and extracts from domestic plant materials is a promising direction in the development of functional beverages since they contain a wide range of substances of various pharmacological properties. Drinks fortified with physiologically active natural components maintain a certain level of this content in human body. They can have a healing or prophylactic effect. However, there is a lack of technologies for the effective production of biologically active substances from plant materials. Moreover, the development of cultivated botanical medicinal plant species remains quite poor. The present study features the qualitative and quantitative composition of biologically active substances of medicinal plants that are endemics of Siberia. They are Rhodiola rosea (Rhodiola rosea L.) and maral root (Rhaponticum carthamoides). The paper introduces a method for increasing their biosynthetic activity. An experiment helped to select a composition of the nutrient medium for the cultivation of callus cultures of Rhodiola rosea (Rhodiola rosea L.) and maral root (Rhaponticum carthamoides) in vitro, which contributed to an increase in the biosynthesis of biologically active substances. For callus cultures of Rhodiola Rosea (line R.r-1k) the following composition was used: mineral base – MS; sucrose – 30 g; inositol – 100 mg; thiamine – 1.0 mg; pyridoxine – 1.0 mg; Ca-panthetonate – 10 mg; kinetin – 0.05 g; naphthyl acetic acid – 0.1 g; 2.4-D – 0.5. For callus cultures of maral root (line R.c -2k): mineral base – SH; sucrose – 30 g; inositol – 100 mg; thiamine – 5.0 mg; pyridoxine – 0.5 mg; nicotinic acid – 5.0 mg; kinetin – 0.1 g; indoleacetic acid – 1.0 g. The authors developed a technology for the production of functional whey-based tonic drink fortified with extract of carotenoids isolated from the fruits of mountain ash and the extract of biologically active substances Rhodiola rosea and maral root. The presence of biologically active substances in the plant and medicinal raw materials gives the drink antioxidant and bactericidal properties, as well as helps to raise the overall state of the organizm and strengthen the immune system.

Bread is the most popular food ever. However, more and more people are abandoning traditional wheat bread in favor of bakery products with various functional additives. Crushed safflower seeds are an unconventional plant additive that is a source of complete vegetable protein, polyunsaturated fatty acids (including linoleic and linolenic acids), dietary fiber, vitamins, and minerals. The present paper introduces a recipe of bread fortified with crushed safflower seeds and safflower oil. The authors studied the sensory and physico-chemical properties of the bread. The prototypes had a smooth surface without cracks and uniform porosity and demonstrated a light yellow color when fractured. The taste and smell were typical of this type of product, with a pleasant delicate flavor and aroma of the additive. There was a slight increase in the porosity, acidity, dimensional stability, and humidity, compared with the control sample. The article contains a technological scheme of production and the formulation of bread with the addition of crushed safflower seeds, as well as some optimal technological production parameters. The authors carried out a medical and biological evaluation of the effectiveness of the bakery products with the addition of seeds and safflower oil in the diet of people aged 18–29 with excess body weight. The conducted research proved the therapeutic efficiency of the developed product in hypocaloric diet for individuals with excess body weight. No tolerability problems or side effects were determined. An optimum method of treatment was developed. The results of the study make it possible to recommend bakery products with crushed seeds and safflower oil for the diet of overweight patients aged 18–29.

In order to expand the range of balanced, high-quality, and safe dairy products, constant work is required to create new technologies, control the quality, as well as to develop new methods for the identification of plant additives. The paper presents some results of the development and quality assessment of cottage cheese mousse with pumpkin puree using physicochemical methods and molecular genetic analysis. An analysis of organoleptic and physicochemical methods revealed that the quality and safety of Adagio pumpkin (S. rero.) corresponds with the State Standard 7975-2013 and Sanitary Regulations 2.3.2.1078-01. The authors introduce a new method for pumpkin puree production. An experiment demonstrated that pumpkin puree meets organoleptic and physico-chemical indicators stated in the requirements of State Standard 32742-2014. The composition of biologically active nutrients was determined as follows: the content of pectin substances was 2.27 g/100 g, fiber – 1.5 g/100 g, and β-carotene – 2.97 mg/100 g. The paper describes a scientifically-based formula and a new technology for the production of a high nutritional value product, i.e. curd mousse with pumpkin puree. The research also included a quality and safety assessment of the developed mousse. A molecular genetic analysis was used to identify pumpkin in the semi-finished product and dairy product. Based on the GenBank NCBI database, the matK chloroplast genome gene was chosen as the target gene. With the help of various software packages based on the matK gene, universal primers were developed and designed. Optimal parameters for amplifying fragments of species-specific pumpkin DNA were defined experimentally. Electrophoregrams were made to visualize the presence of pumpkin in the puree and cottage cheese mousse. As a result, the classical polimerase chaim reaction (PCR) method was recommended to identify pumpkin in food products with the determination of amplification products in agarose gel using primers developed on the basis of the matK gene of the chloroplast genome.

The research features the technological challenge of producing jelly desserts by replacing gelatin by non-starch polysaccharides of plant, bacterial, and algal origin (separately or in binary mixtures) in order to overcome religious and ethical constraints. The authors focused on the texture which is responsible for gel network formation of desserts. Hydrocolloids are widely used in many food formulations to improve quality attributes and shelf-life. The polysaccharides under analysis included alginate, pectin, iota-carrageenan, konjac glucomannan, xanthan, and guar gum, separately or in binary mixtures. The experiment made it possible to determine polysaccharides and their optimal concentrations (konjac glucomannan 0.4 % : xanthan gum 0.6 %; locust bean gum 0.2 % : xanthan gum 0.8 %; iota-carrageenan 0.4 %) as gelling agents for the production of desserts without gelatin. Formation of a gel network in desserts occurs as a result of a complex interaction of hydrocolloids, milk fat, and sugar. Structure formation of jelly desserts with polysaccharides occurs already at 18 ± 2°C in 20–40 minutes. In contrast, the structure formation of the control sample occurred at 4 ± 2°C in 2–3 hours. Sensory evaluation of the products was conducted by panellists according to the following criteria: taste, colour, consistency, aroma, and appearance. The paper also describes an analysis of texture indicators. The shelf-life was assessed according to moisture content and water activity as 24 hours at 4 ± 2°C. Several economically-viable new formulations were identified: they successfully reproduced the essential attributes of well-established and widely-consumed traditional gelatin desserts.

The research featured consumer properties of 18 varieties of apples, 12 varieties of pears, and 6 varieties of strawberries grown in the Republic of Belarus. The research objective was to study the sensory component composition of apples, pears, and strawberries to select varieties with the best consumer properties. Hexylacetate was detected in Charovnitsa, Zaslavskoye, Belarusian Sinap, and Pamyat Sikory apples. As for the pear varieties, Alesya, Belan, and Krasavita were found to contain butylbutanoate and hexylbutanoate. In all the samples of fresh pears, aroma-forming esters were mainly represented by hexylacetate and butyl acetate. Pears that reached full ripeness contained esters of unsaturated acids that are responsible for a characteristic pear flavor: methyl 2.4-decadienoate and two isomers of (cis-, trans-) ethyl-2.4-decadienoate. All the samples of strawberry contained linalool, which gives a floral flavor. Its quantity differed according to the variety: from 0.4% (Rusish variety) to 4.53% (Alpha variety). The apple varieties of Pamyat Kovalenko, Krasavita, and Dyayment had a high content of sugars (≥ 10%). Charovnitsa, Belana, and Zorka had a low acidity and can be recommended for the production of juice products for children. All the studied varieties of pears had a low sugar content (about 7%) and organic acids (≤ 0.3%), which also makes them suitable for children. The average acid content for strawberry was 9.1 g/kg, while the predominant acid was citric. However, Belarusian strawberries contained less sugar than stated in the databases, an average of 52.5 g/kg. Belana, Dyayment, Zorka, and Charovnitsa apples and Pamyat Yakovleva pears demonstrated a high sugar-acid index and the most harmonious taste. Garden strawberries had a low sugar-acid index value, not more than 6.2. The samples revealed various amounts of catechins, phenolic acids, flavonols, and anthocyanins. The obtained data on the component composition of 18 varieties of apples, 12 varieties of pears, and 6 varieties of garden strawberries of the B elarusian selection can serve as a marker of the authenticity of products by comparing with the existing database of basic quality indicators and the composition of raw materials.

Confectionery products of high nutritional value are affordable and rich in vitamins and minerals. Their development requires new raw materials with a high physiological value, which would be available on the local consumer market. Vegetable syrups can be used in sugar confectionery products, especially if they are fortified with vitamins and minerals. The present research proves the expediency of using fortified syrups in the production of sugar glasses. This type of caramel has a high energy value but no biologically valuable substances in the composition. Therefore, fortified syrups increase the biological value of the product. The study featured samples of sugar glasses with syrups fortified with rosehip, sea buckthorn, lemongrass, and cranberries. The paper describes their nutritional value, as well as the therapeutic and prophylactic properties of the syrups. It also contains data on the sensory quality, physic-chemical parameters, and the nutritional value.

Spray drying is currently used to obtain powder products from suspensions. It is considered the most effective type of drying for such media. The complexity of the drying process is associated with thermal destruction of components, which degrades the properties of the product and imposes significant restrictions on temperature condition. The present research features the simulation of transient modes of operation of the solenoids to generate a controlled cavitation effect when applied to a stream of acoustic vibrations using a magnetostrictive generator of ultrasound. The authors propose a new design of spray nozzle for drying suspensions with counter-connected solenoids. Such solenoids can cause deformation of the main suspension supply line. The intensity of the cavitation processes depends on the dynamics of the solenoid actuation. The paper introduces a mathematical modeling of transient modes of operation for ultrasonic frequency generator solenoids that create a controlled cavitation effect when applied to the jet of acoustic oscillations of this frequency. When modeling the process of operation of solenoids, the main criterion for changing the intensity of cavitation is the average rate of change in the volume of the cavity at the stage of its collapse, related to one cycle of oscillations for a spherical cavity. An increase in the static pressure of the liquid led to a shift in the phase of the collapse of the cavity. As a result of the chosen mathematical model, a numerical experiment with modeling in the MathCAD program was carried out. It revealed some graphical dependences of the change in U(t), L(t), and R(t). The obtained data allow one to predict the ballast induction and active load (R, L) for the control of transients in the solenoid of the ultrasonic generator. These dependences make it possible to choose more effective parameters for drying suspensions, which is especially important for heat- sensitive components.

Food is one of the major health-determining factors. Thus, any product should be of high quality and contain valuable substances. Therefore, the authors selected a flour baking mix with a high content of protein to determine the key operation parameters of the vibration mixer. There have been a lot of researches that feature flour baking mixes with the help of various mixers. The present research employed an original vibration mixer of continuous action with a method of “consecutive dilution”. The experiment determined the speed of vibrotransportation of the protein mix through the operating part of the device. The power consumption of the device, as well as the speed of the vibrotransportation of the baking mix, can affect the process of mixing. Therefore, the authors studied the mutual impact of the technological parameters of the mixer and the power consumption. The analysis helped to determine the effect of the key parameters on the speed of vibrotransportation of the flour baking mix. The speed υ increased with the increase in the oscillation frequency of the operating part f and the vibration amplitude A. A high amplitude and oscillation frequency proved to increase the value of power consumption of the vibromixer. Its key operation parameters were as follows: the amplitude of vibration A = 0.0035 m, the angle of vibration β = 45°, the height of the vibroboiling layer = 0.02 m, the diameter of perforation of the operating part of the device d = 0.007 m.

Flax seeds are a valuable source of several active components and can be used for controlled modeling of bakery food value. The study featured flour mixes of first grade wheat flour and flaxseed flour (flax meal) in the ratio 92.5%:7.5%; 90.0%:10.0%, and 87.5%:12.5%. The rheological properties of the dough were studied using the Mixolab (Chopin Technologies, France). The laboratory was located at the Polzunov Altai State Technical University (Barnaul, Russia). The mixolabogram and radial diagram were used to define the differences in the parameters of the rheological profile of the 4 flour samples. With the increase of flaxseed flour in the composition, the mixing time increased from 5.58 to 5.77 minutes, and the stable state of the dough became longer: from 9.25 to 9.67 minutes. The water ab-sorption capacity of flour mixes directly depended on the dosage of flax flour and increased from 69.4 to 72.9%. However, viscosity, amylolytic activity, and retrogradation revealed inversed dependence on the dosage of flax flour. The moisture content of the dough increased from 47.0 to 50.0% and the initial acidity of the dough increased from 2.5 to 3.5 degree with the increasing dosage of flax flour, which changed the dynamics of acidification during fermentation. This resulted in a more rapid maturation of dough and reduced the total fermentation period from 90 to 60 minutes. Thus, the flax flour mixes can be characterized as “fillers” that produce bread of reduced volume. The authors state the optimal dosage of flax flour as 7.5–10.0% and propose various modes of the technological process for obtaining bread with good consumer properties.

As quality requirements get lower and lower, the quality of buckwheat grain meant for buckwheat groats is deteriorating. The most typical example is winter buckwheat grain. Buckwheat grain has to be sorted according to various fractions before scouring. Thus, the mechanical properties of these fractions remain a relevant field of study. The research features the dynamic pattern in the mechanical properties of the main fractions of winter buckwheat grain according to fraction before and after storage. The research subject is fractions of buckwheat sorted according to grain size before scouring. The buckwheat grain was harvested in the foothills of the Altai Territory in May 2015; it meets the necessary standards. There were twelve samples: six samples were harvested and sent for recycling (May 2015); other six samples were stored for eight months up to March 2016. The buckwheat did not pass the temperature treatment stage. The smaller fractions revealed a greater deformation before and after storage. That can lead to a higher deformation rate during scouring. Thus, the changes in the mechanical properties of winter buckwheat grain occur differently for each fraction.

The research features the rational conditions of the process of rapid freezing for unpackaged small-sized foods by the method of continuous and discrete heat sink. The paper presents a graphical interpretation of the calculations of the average volume temperature for various temperature regimes that are used to freeze semi-finished products. The method makes it possible to determine the temperature at any time. The experiment defined the most rational range of air circulation speeds with a continuous heat sink in the range from 4 m/s to 6 m/s. The article features curves of changes in temperature and heat flux density during the rapid freezing of small-sized semi-finished meat products. They show the nature of the changes in the air coefficient of the meat sample heat transfer curves and the medium velocity of the object air. An increase in the heat flux density and a reduction in the duration of freezing by about 1.4 times occurred when the temperature of the cooling medium decreased from –20°C to – 40°C at an air speed of 6 m/s. The research determined the process characteristics of rapid freezing in continuous mode using a discrete heat sink. The authors describe the comparative characteristics of the change in the duration of the freezing process and the speed of the process with continuous and discrete heat sinks. The study presents the curves of changes in temperature and heat flux density during rapid freezing of small-sized semi-finished meat products, depending on the conditions of heat transfer. When a discrete heat sink was used, the duration of the freezing process was fpund to be 20 min, while with a continuous heat sink it lasted 26 min. The paper also includes a thermogram and the kinetics of heat sink during freezing in discrete conditions, as well as a software program for quick freezing of semi-finished minced meat products. The indicators of the meat quality are considered depending on the conditions of the heat sink, as well as the change in the physicochemical properties of the product after freezing and during storage. Studies of quality indicators of small-sized semi-finished meat products were carried out in the laboratory of the scientific-innovative enterprise “Sibagropererabotka” (Novosibirsk, Russia).

The present research features the problems of wheat processing. Wheat processing has its own specific features. For instance, the process of gluten extrusion forming is very complex since it is associated with the visco-elastic and adhesive properties of raw gluten. The article discusses the results of applying the numerical finite difference method to the Navier-Stokes equation in the case of the one-dimensional problem when a cooled viscoelastic material has to pass through circular nozzles. The paper also features the obtained surface model of velocity evolution and some averaged results for the possible automation of the process. The viscosity properties of raw gluten are variable and depend on temperature, chemical composition, and properties of the raw material. Modeling makes it possible to characterize the properties of the material and its behavior in various situations. Such research demands neither additional time nor significant costs. The authors identified patterns of movement for raw gluten in the extrusion molding unit and selected the most appropriate automation system to control the speed of its movement to the molding assembly in the grinder feed screw. The significance of the research is obvious for subsequent physical and mathematical modeling of heat and mass transfer processes of vacuum freezing and drying and granulating of gluten extrusions. The results of the research presented in the article are consistent with the available information on this topic. The present approach to solving the problem of choosing the best rational hydrodynamic regimes was applied due to the complexity of the experimental determination of velocity fields and the difficulty of analyzing the Navier-Stokes system of hydrodynamic differential equations with variable proportionality coefficients.

Every year, hundreds of thousands of tons of fruits and vegetables are supplied to the territory of the Russian Federation by exporting producers from different countries. During transportation and storage, the supplied fruits and vegetables undergo various physical and biochemical changes, leading to weight loss and changes in quality indicators. Loss of moisture during transportation is one of the main causes of damage to fruits and vegetables. The relevance of the research topic is determined by the need to minimize the loss of mass and moisture of exotic fruits during transportation and storage in warehouse conditions.Objective: to establish the rates of loss of 10 samples of exotic fruits. The samples included Thai pineapple, Thai watermelon, guava, cantaloupe melon, carambola, Thai mango, papaya of Holland variety, green papaya, passionflower (passion fruit, pitaya). The fruits were transported by air from Thailand (Bangkok) to Krasnoyarsk. The flight duration was 8 hours, flight altitude – 10,000 m. The storage conditions were as follows: temperature – 5–8°C, humidity – 47%, storage time – 10 days in winter period. The paper presents the results obtained for the dynamics of mass and humidity during transportation by air of samples of exotic fruits and during storage in warehouse conditions. It was established that the loss of mass and moisture of exotic fruits in the process of transportation and storage occurred in all samples. The highest percentage of weight loss was observed in Thai mango and amounted to 2.93%. The greatest loss of moisture during storage in warehouses was observed in Thai watermelon (3.5%), the smallest – in Thai pineapple (0.5%). The largest weight loss was set for guava (4.6%), the smallest – for Thai watermelon (0.5%).

It featured the dynamics of the biochemical parameters of potato tubers in the autumn and winter storage peri- od. The samples were gathered in 2011–2013 during field experiments. The experiments included 12 various doses and ratios of mineral fertilizers under drip irrigation. The soil was leached chernozem (Voronezh region). During 3 storage periods (Sep- tember–April), the content of vitamin C in moderately fertilized tubers decreased by 3.0–3.2 times. The content of vitamin C in heavily fertilized tubers decreased by 3.3–3.4 times. The loss of dry matter and starch at small and moderate doses of fertilizers N30-60P90-120K60-90 amounted to 1.4–1.5 and 1.0–1.1%. The loss of dry matter and starch from high doses of fertilizers N120-150P180-210K150-180 equaled 1.6–2.0 and 1.4–1.7%. The content of nitrates in the tubers gradually decreased during stor- age, and the greatest decrease occurred in April. For moderately fertilized tubers, the residual amount decreased by 3.2–3.3 times by April. For heavily fertilized tubers, it decreased by 2.5–2.9 times against 3.7 times in the control sample. Enhanced nitrogen and nitrogen-potassium fertilizer worsened all the biochemical indicators of the potatoes. In order to maintain optimal biochemical pa- rameters of tubers during storage, the proportion of phosphorus (kg/ha of active substance) had to be increased by 1.5–1.7 times as related to nitrogen. The share of potassium was increased by 1.3 times. The best results (yield = 37.8 t/ha, optimal biochemical pa- rameters, concentration of nitrates = 36.6 mg/%) were achieved by drip irrigation and application of N90P150K120 kg/ha of active ingredient. A dose of N120P180K150, (yield – 41.5 t/ha) was found beneficial, provided the potatoes were filled separately from the total pile. Such potatoes have to be sold at the end of the storage period, when the concentration of nitrates in tubers becomes 2.5– 2.9 times lower.

The research features a comprehensive study aimed at increasing the technological compatibility of multilayer packaging materials. The paper describes a recycling technology with the prospect of returning the resulting secondary raw materials to the production cycle. The research included the following tasks: to conduct a comprehensive study of polyolefin mixtures modified by ethylene propylene copolymer; to study the effect of the copolymer on the rheological and physicomechanical properties of polymer compositions; to propose a technology for the recycling of secondary polyolefin mixtures. The research involved the following methods: the capillary viscometry method was used to determine the rheological properties of polymer compositions; the tensile test method was employed to define the physicomechanical properties of the compositions; the pycnometric method was used to assess the density of the mixtures. The study featured such polymers as polyethylene, polypropylene, and ethylene-propylene copolymer, which was chosen as a link between the polymers. The authors obtained polymer compositions in various ratios of polyethylene, polypropylene, and ethylene-propylene copolymer: 70:30:0; 68.5:28.5:3; 65:25:10; 30:70:0; 28.5: 68.5: 3; 25:65:10. The article describes the process of modifying polyolefin compositions based on polyethylene and polypropylene by ethylene-propylene copolymer on a single-screw extruder. The authors defined the rheological properties and the deformation-strength characteristics of the polymer mixtures. Repeated processing proved to lead to a decrease in the physicomechanical properties of polyolefin mixtures, with the exception of compositions based on polyethylene and polypropylene in the ratio of 30:70, where the breaking stress increased. The number of processing cycles increased the melt flow rate of the mixtures. The proposed technology is meant for producing multilayer packaging materials using packaging waste in the middle layer for contact with food.

The paper describes a comprehensive study of the strategic planning of innovative development at industrial enterprises: the main directions, the basic principles, and the system as a whole. The research features the planning mechanism of innovations and investments. It introduces a scheme of strategic management of innovative development of industrial economic entities and their typological classification. Based on foreign and domestic academic sources, the authors systematized innovative strategies and prospective directions of feed industry development. Oil cake and seed cake production make up an important part of feed industry worldwide. The research included monitoring of this industry segment. It featured a case of a regional experimental compound feed plant (stock company OAO Voronezh). The study revealed some basic conditions and directions of innovativedevelopment of feed production under the import substitution and strategic goals policy.

Currently, chocolate and chocolate products remain quite popular among various consumer groups. According to experts, the average Russian consumes 4.7 kg of chocolate and chocolate products per year. The Russian chocolate market is 91% Russian-made. The market offers a wide range of products for various market segments. The high level of competition among the major domestic producers stimulates them to systematically study consumer preferences and adapt to them. In contrast with the central part of Russia, such market novelties as chocolate with salt, pepper, and other specific additives take root quite slowly in the non-metropolitan areas. The present research features the Kemerovo market of chocolate products and the preferences of Kemerovo residents. The main research method was questioning. The study revealed that the main target audience is the economically active female population aged 18–39. The greatest preference is given to milk chocolate in the middle price segment. As for the most preferred chocolate packaging, most respondents singled out plastic and paper packaging. As a rule, chocolate is purchased at a supermarket. Consumers are positive about new products but prefer to buy their favorite types of chocolate. The data obtained allowed the authors to formulate recommendations for chocolate producers taking into account the requirements of the main target audience, their preferences in taste, packaging, and the place of purchase.