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TRENDS IN THE DEVELOPMENT OF THE PROCESSING OF MELONS AND GOURDS
Mariam Alimardanova1, Dinara Tlevlessova2, Laila Syzdykova3, Abdieva Karlygash4, Elena Petrenko5, Alexandra Brindyukova6
department of Food Technology, JSC Almaty Technological University, Almaty, Republic of Kazakhstan ORCID: https://orcid.org/0000-0003-4861-7862
2Department of Food Technology, JSC Almaty Technological University, Almaty, Republic of Kazakhstan ORCID: https://orcid.org/0000-0002-5084-6587
3JSC Almaty Technological University, Almaty, Republic of Kazakhstan ORCID: https://orcid.org/0000-0002-6299-5061
4JSC Almaty Technological University, Almaty, Republic of Kazakhstan ORCID: https://orcid.org/0000-0003-0111-6737
5Department of Food Technology, JSC Almaty Technological University, Almaty, Republic of Kazakhstan ORCID: https://orcid.org/0000-0002-1252-6216
6Department of Food Technology, JSC Almaty Technological University, Almaty, Republic of Kazakhstan ORCID: https://orcid.org/0000-0002-6085-4003
S Corresponding author: Elena Petrenko, e-mail: 2.petrenko.elena.1@mail.ru
ARTICLE INFO
ABSTRACT
a s
s
Article history: Received date 05.01.2023 Accepted date 21.02.2023 Published date 28.02.2023
Section:
Food production DOI
10.21303/2313-8416.2023.002870
KEYWORDS
watermelons
melons
technology
technique
processing
characteristics
indicators
rheology
The review of equipment for processing and technology of processing melons and gourds is given. Primary processing of gourds has not been industrialized in the CIS countries and abroad until recent years. Theoretical prerequisites for the creation of products based on melon are presented, the issues of rational use of melon for the production of long-term storage products are highlighted. The main physical-mechanical and rheological properties of pumpkin, melon and watermelon fruits are given. The proposed options for equipment and technological lines for the processing of watermelon, melon, pumpkin fruits are presented. The technologies for processing the fruits of watermelon and melon are described.
The object of research: Melons and gourds, namely processing technology.
Investigated problem: Imperfect technologies for processing melon fruits.
The main scientific results: systematization of data on the problem of processing melon
fruits for food in order to choose a rational way to improve processing technologies.
The area of practical use of the research results: The bottom line is the developed
technologies
Innovative technological product: technology for processing gourds.
Scope of the technological innovative product: food industry (Food production).
© The Author(s) 2023. This is an open access article under the Creative Commons CC BY license
1. Introduction
1. 1. The object of research
The object of research is scientific and technical information, articles and works of scientists on the processing of melons and gourds.
1. 2. Problem description
Gourds (watermelon, melon, pumpkin) are of great food, fodder, technical and agrotechni-
cal importance. The products of these crops can be consumed both in their natural form and in the form of processed products.
The fruits of melons and gourds are rich in vitamins, minerals and are very beneficial for
human health. Growing pumpkins, zucchini, squash and melons is not particularly laborious, and the plants themselves are relatively unpretentious to growing conditions, they are able to produce a large harvest of not only tasty, but also very useful fruits.
A variety of vitamins allows the use of pumpkin as a prophylactic and therapeutic agent for various diseases. The peeled pulp of melons and gourds can be widely used to obtain juice concentrate, jams, marmalade, candied fruits, the production of freeze-dried powder, baby food, puree, porridge, paste, and the bark after drying can be used to obtain pectin.
Modern agricultural production requires the solution of many problems, among which the increase in crop yields and the increase in the commercial yield of high-quality products while reducing overall costs and reducing losses are of decisive importance. Of particular relevance is the all-round reduction or complete elimination of the share of manual labor due to the comprehensive mechanization of technological processes.
One of the main factors hindering the use of gourds in the food industry is the high labor intensity of post-harvest processing in order to obtain purified pulp. In this case, the issue of mechanization of the separation of seeds from the pulp has not been practically resolved. The technology for removing the outer cover from the fruits of gourds, as a rule, is based on the use of manual labor, since the existing constructive and technological solutions for peeling fruits from the bark do not provide efficient and high-quality work during the processing of gourds.
To solve this problem, it is necessary, on the basis of an analysis of the features of the development of gourds, to substantiate a rational technology and develop technical means for mechanizing the processes of processing pumpkin fruits for both technical and food purposes.
Not only domestic scientists, but also scientists from foreign countries are working on the problem of processing gourds. Works are carried out in different directions and for different types of fruits: pumpkin (peeling, seeds, harvesting); melon (peeling, seeds, processing of seeds for oil, etc.); watermelon (peeling, juice extraction, etc.).
1. 3. Suggested solution to the problem
Let's bring review from foreign bases. For processing melon seeds, a peeling machine is proposed to solve the problems associated with peeling melon seeds. Parameters evaluated include the efficiency of shelling, the percentage of shelled and damaged seeds, throughput and productivity of the machine. The machine has been assembled and consists of a hopper, a frame, a peeling and cleaning unit, chutes and an engine. The peeling operation was carried out using melon seeds in three different moisture levels (6.99, 11.90 and 18.32 %) and at 2 peeling speeds of 2500 and 1500 rpm. The results obtained showed that a shelling speed of 1500 rpm and a moisture content of 18.32 % had the best cleaning efficiency of 76.30 % and the lowest percentage seed damage of 22.60 % compared to a shelling speed of 2500 rpm and a seed moisture content of 6.99 %, which had a shelling efficiency of 70.0 % and a percentage of seed damage of 68.10 %. The productivity of the machine and equipment is 7.95 and 9.56 kg/h, respectively. Practical application: the built peeler is practically applicable for shelling melon seeds and subsequent cleaning it from chaff. This will solve a common problem associated with the processing of melon seeds, which limits their further use [1].
In the works of Vasylenko S. V., Kopylov M. V., Kairbaeva A. E. it was found that the percentage of shelling for squeezing oil from melon seeds is an important indicator, so when the seeds were peeled and clean from the husk, the oil yield was low, the machine strained during the extraction, with a percentage of 70/30 seeds and husks, the machine easily pressed the oil and the yield was high [2].
Also proposed is a machine for cleaning melon from seeds and seed bed in a whole melon. Based on the method of rectangular circulation diagram, a machine for extracting the pulp of seed melon was designed. An improved rocker cam was used for the melon feed mechanism, a mechanism with 2 round pins and a 4-channel wheel mechanism was chosen to realize the precise indexing movement of the melon saddle in the cork, and a flat-bottom cam mechanism with an improved rod drive mechanism was used for the saddle lifting tool. An orthogonal experiment was carried out and the following optimal digging parameters were determined: type of digging tool - semi-cycle, speed of the digging tool - 240 rpm, installation angle of the digging tool - 15°. Repeated tests have shown that the degree of purification is more than 98 %, the degree of absence of seeds of grain is more than 98 %, the degree of loss is less than 2 % and the degree of destruction is less than 1 %, respectively [3].
Marketing is taking over our lives everywhere, and for the convenience of consumers, fruit cuts, freshly cut slices of watermelons and melons are offered. The paper [4] proposes a machine for cutting watermelons and melons into slices for the convenience of selling in supermarkets. The machine cuts the fruits of watermelons and melons into disks, the results given in this work show that this type of cutting is convenient for consumers and is packed in sealed packaging for preservation
and can be stored for a week under refrigeration conditions. Improved shelf life of freshly cut melons and watermelons is reported in [5] This study assessed the impact of post-harvest processing and packaging technologies on consumer acceptability and taste profiles of freshly cut watermelons. Changes in odor of samples stored at 3°C correlated with consumer sensory ratings for color, fresh appearance, firmness, aroma, and taste. Freshly cut watermelon, sealed in unperforated film and stored at 3°C for 6 and 8 days, achieved the highest taste and overall sensory scores compared to modified atmosphere (5 % O2 and 10 % CO2).
A machine for extracting juice from watermelon fruits was proposed and designed [6]. The results of the analysis of productivity showed that the type of fruit and the condition of the peel significantly affect the yield in the amount of 1 %. The percentage of juice yield from peeled and unpeeled watermelons was 89.5 % and 89.7 %, respectively. The extraction efficiency was 96.6 % for peeled watermelons and 97.1 % for unpeeled ones. Production losses were 2.9 % and 2.6 %, respectively. The proposed device is easy to use and maintain, so it is perfect for the needs of small fruit juice producers and can help to achieve cost-effectiveness for small production.
The mechanical properties of fruits and vegetables can be applied to improve the efficiency of processing equipment, including cleaners. As a rule, the effectiveness of a mechanical cleaner depends on the influence of various forces on the performance of the machine. Useful forces such as tearing and cutting are deliberately applied for cleaning; while unwanted forces such as shock and compression can reduce the impact of the former forces. Unwanted exercise may also be a major cause of common problems such as bruising [7]. Knowing the mechanical properties of agricultural products will help designers apply forces correctly.
One of Harker's publications et al., [8], which is related to the mechanical properties of melon, focuses on comparing instrumental (using puncture, shear, and tensile strength) and sensory measurements of tissue strength and juiciness for several fruits and vegetables, including watermelon and cantaloupe. They only studied the cellular basis of the flesh to determine the characteristics that affect sensory texture, signs of firmness and succulence. Attempts to find any useful published data on the mechanical properties of melon varieties that could be used as a database for the design of a mechanical cleaner have been unsuccessful. The current study was conducted on three common varieties of melon, namely cantaloupe melon, honeydew melon and watermelon, to explore selected mechanical properties that would form a database for designing cleaning equipment. The mechanical properties of three common melon varieties were measured. These are strength, breaking force, shear strength, maximum shear force and cutting force. The role of the peel (%) for each property was also calculated as the relative contribution of the peel to the crude product. Peel resistance at peeling was statistically found to be the same (/>>0.05) for all grades. The same result was found for unrefined products. The use of tear force was not recommended for cleaning watermelon due to the similar values of this property for cleaning it and the uncleaned body. The required energy for cleaning all three varieties of melon was determined to be 500 Nm. It is not recommended to peel melons with cutting tools [9].
The mechanical properties of three common pumpkin varieties were evaluated and compared statistically. Strength, tear strength, shear strength, and cutting strength were determined for Jarradale, Jap, and Butternut grades. The study was carried out in three cases of flesh, skin and crude product, ignoring the strength and breaking strength of the flesh. The relative contribution of the skin to the crude case of each property was evaluated. The grades were found to be statistically similar in tear strength, toughness and maximum shear strength in the unrefined cases. Also, the leather of the three grades showed the same shear strength (/>0.05). Varieties Jap and Butternut showed similar values in some other properties. The maximum flesh shear strength of the flesh, the shear strength of the unpeeled case, and the relative contribution of the skin to the shear strength of the unpeeled case were close (/>0.05) for these varieties. Jarradale had no difference in flesh shear strength with the other two varieties. It was also similar (/>0.05) to Japo in the relative contribution of leather to the shear strength, tear strength, and toughness of the uncleaned casing [10].
In the following study, a heavy crop harvesting robot (HRHC) was developed and evaluated. This robot consists of a robotic tractor as a mobile platform, a specially designed robotic arm for this application, a developed pumpkin end effector and a control system. The final evaluations were focused on eight parameters including working space, system resolution, harvestable area, accuracy, repeatability, harvest success rate, cycle time, damage rate. The results showed that this
robot has a harvest success rate and a damage rate of 92 % and 0 % respectively. The average cycle time in scenarios 1, 2 and 3 was 58.7, 41.9 and 35.1 s, respectively. The working space parameters of the final system, including working space volume, harvesting surface and harvesting length, were 5.662^109 mm3, 2.86*106 mm2 and 800 mm, respectively, which were 70.6, 81.3 and 99 % on the required parameters in the design system, respectively. Accuracy and repeatability were 4.5 and 5.23 mm, respectively. The system resolution in the x, y, and z directions was 1 mm, which had a tolerance of 75, 50, and 25 ^m, respectively. These results show that the system has sufficient motion resolution, accuracy and repeatability for pumpkin harvesting. The harvest success of the HCRH system (100 %) was higher than the overall average harvest success of previous studies between 1984 and 2012. During the experiments, no damage was found to the fetuses. The result of the experiments meets certain requirements and the HCRH system, recognized as applicable for harvesting pumpkins in the field [11].
To automate the collection of melons, a mobile Cartesian robot has been developed that collects melons at previously known coordinates, the principle is based on Markov chains. Numerous experiments have proven the applicability of this robot for collecting melons [12].
Improving food quality and reducing waste in mechanical operations in the food industry requires comprehensive knowledge of material response to stress. While research has focused on the mechanical response of the food material, the amount of waste after harvest and during processing steps is still quite high in both developing and developed countries.
The development and evaluation of the main model of the mechanical reaction of hard-skinned vegetables during post-harvest and processing operations is proposed in the following study [13]. The model focuses on both the tensile and compressive properties of pumpkin pulp and rind tissues, where the behavior of these tissues varies depending on various factors such as rhe-ological response and cellular structure. The modeling process took into account both the elastic and plastic response of the tissue, and applied finite elasticity in combination with pseudoelasticity theory to create the model. The results were then validated using published results from experimental work with pumpkin pulp and skin under uniaxial tension and compression. The determining coefficients for peeling in tensile testing were a=25.66 and p=-18.48 MPa, and for meat a=-5.29 and P=5.27 MPa. In compression, the governing factors were a=4.74 and p=-1.71 MPa for skin samples and a=0.76 and p=-1.86 MPa for flesh samples. The constitutional curves accurately predicted force values and are close to the experimental values. The curves were fitted for the entire stress-strain curve, as well as for the portion of the curve up to the bioproduct yield strength. The simulation results showed good agreement with the empirical values, and the design curves are very similar to the experimental ones.
For tensile testing of pumpkin pulp and peel samples, knowledge of the properties of similar fruits was applied, in particular, on arc samples with a constant loading rate of 20 mm/min-1. The results showed that the maximum tensile stress of pumpkin pulp and peel samples was 0.535 and 1.45 MPa, respectively. The modulus of elasticity of the pulp and peel samples was 6.82 and 25.2 MPa, respectively, and the values of the fracture modulus were 14.51 and 30.88 MPa, respectively. The results of tensile tests were used to develop a finite element model of mechanical peeling with hard vegetable skins [14].
In this study, an empirical study was made of the mechanical properties of pumpkin peel. The test was part of the FE simulation and simulation of the mechanical peeling stage for hard-skinned vegetables. The compression test was carried out on a Japanese variety pumpkin. In addition, the stress-strain curve, bioavailability and strength of the pumpkin skin were calculated. The energy required to reach the biological yield strength was 493.75, 507.71 and 451.71 N/mm, for loading speeds of 1.25, 10 and 20 mm/min, respectively. The average value of the force on the biological yield strength of the pumpkin peel was 310 N [15].
There are various load sources that deform crop tissues, including impact, compression, and tension. The Scanning Electron Microscope (SEM) method is a common way to analyze cellular changes in materials before and after these loading operations.
In the article [16], structural changes in the peel and tissues of pumpkin under mechanical load are studied. Compression and indentation tests were performed on skin and flesh samples. The structure of the samples was then fixed and dehydrated to capture cellular changes under SEM. The results were compared with images of normal peel and skin tissues. The findings suggest that
normal flesh tissue had larger cells, while the skin's cellular structure was smaller. Structural damage was clearly observed in the tissue structure after compression and indentation. However, the damage from the flat end indenter was much more severe than from the spherical end indenter and compression test. An integrated deformed tissue layer was observed in compressed tissue, while indentation tests formed a deformed area under the indenter and left the rest of the tissue intact. There was an obvious broken layer of cells on the walls of the hole after the indentations at the flat ends, while the spherical indenter created a flattened layer around the hole. In addition, the effect of stress on skin samples was less compared to meat samples. Experiments have shown that the rate of tissue damage at a constant load rate is highly dependent on the shape of the equipment. This fact and the observed structural changes after loading highlight the importance of adjusting post-harvest equipment to reduce tissue damage to crops.
A line for processing watermelons and a plant for obtaining watermelon pulp and seeds were described in [17].
The aim of the study is study of innovative research in the field of processing melons and gourds and food production based on them.
2. Materials and methods
2. 1. The chemical composition of melon fruits
Research work was carried out in the accredited testing laboratory "Food Safety" of the Almaty Technological University, where the following indicators of melons of late ripening varieties were determined: mass fraction of solids, mass fraction of protein, mass fraction of fat, mass fraction of pectin substances, content of vitamin C, carotenoids, potassium, magnesium, iron, organic acids and antioxidant activity, using modern standard research methods [18].
The melon variety Myrzachulskaya is more balanced in composition, it has a higher content of vegetable protein by almost 3.8 times compared with the Zhuldyz variety and 1.9 times with the Ameri variety [19].
Myrzachulskaya variety contains a larger amount of fat - 0.26 %, which is 0.134 % higher than that of the Zhuldyz variety and 0.17 % higher than that of the Ameri variety. In terms of the content of the mass fraction of pectin substances, the Myrzachulskaya variety is inferior to the Zhuldyz variety by 0.11 g/100 g, but slightly exceeds the Ameri variety - by 0.045 g/100 g.
Myrzachulskaya variety in terms of the content of ascorbic acid and vitamin C are 2.78 mg/100 g higher than that of the Zhuldyz variety and 6.61 mg/100 g higher than that of the Ameri variety.
Myrzachulskaya and Ameri varieties (respectively 0.12, 01124, 0.104 mg/100 g).
Melons are rich in potassium, magnesium and iron, which are so necessary to maintain the cardiovascular system of the body in good shape.
Ameri variety shows the best results, it contains 117.38 mg/100 g of potassium, 10.846 mg/100 g of magnesium and 1.193 mg/100 g of iron. The second place is occupied by the Myrzachulskaya variety - 116.64 mg/100 g of potassium, 10.812 mg and 1.007 mg/100 g of iron. In the Zhuldyz variety, respectively, there are 113.0 mg/100 g of potassium, 10.43 mg/100 g of magnesium and a significantly lower iron content - only 0.353 mg/100 g.
In the Ameri variety, the content of malic acid is 348.8 mg/kg, which is significantly higher than in the Zhuldyz variety by 47 mg/kg and by 58.8 mg/kg in the Myrzachulskaya variety. According to the content of citric acid, the Zhuldyz variety differs- 47.5 mg/kg, then the Myrzachulskaya variety - 27.0 mg/kg and the Ameri variety - 18.0 mg/kg. Succinic acid is more contained in the Myrzachulskaya variety - 62.0 mg/kg, less in the Ameri variety, only 6.3 mg/kg, and in the Zhuldyz variety of succinic acid - 56.2 mg/kg. The total antioxidant activity in the Ameri variety is 28 mg/100 g. In the Myrzachulskaya and Zhuldyz varieties, the level of antioxidant activity is almost the same, 27.4 mg/100 g and 27.3 mg/100 g, respectively.
Thus, taking into account the rich chemical composition of melons of late ripening varieties, they should be used for the production of long-term storage products of increased nutritional and biological value in order to expand the range of products from non-traditional types of food raw materials with a high content of biologically active substances.
Calorie content was 34-36 kcal/100 g. Nutritional value, g/100 g: proteins - 0.4-0.6; fats - 0.240.35; carbohydrates -7.3-7.5; dietary fiber -0.8-1.0; water -88-92; unsaturated fatty acids - less than 0.1; saturated fatty acids - less than 0.1.
Myrzachulskaya, respectively: water - 6.0-6.2; lipids - 25.0-26.5; protein (Nx 6.25) - 22.525.5; starch and soluble sugars - 10.0-11.0; pentosans - up to 8.0; cellulose - 21.4-20.0; ash - 3.02.5. The kernel contains up to 30-50 % oil, and the husk contains 0.5-0.6 %.
To study the pectin content in melon fruits, the following varieties of melons sold in the Almaty region were taken: Inghirnaya(sample No. 1), Gulyabi (No. 2), Myrzachulskaya (No. 3), Gurbek (No. 4) and Ameri (No. 5).
3. Results and discussion
The results of the analysis showed that the moisture content in different parts of the melon is not the same. So the highest humidity was in the crust 88.6 %, and the smallest in the placenta 82.8. The moisture content of the pulp was 82.8 %. The mass fraction of pectin substances per absolutely dry matter in the crust is 10.9 % more than 2 times higher than in melon pulp 5.09 %. The rather high content of total pectin in the placenta is 7.44 %, which makes it a potential object for the extraction of pectin, possibly in the form of an intermediate product - liquid pectin, for use on site for the production of jams or pectin-containing drinks [20].
The content of pectins in the raw product, due to its high moisture content, does not exceed 1.28 % in the placenta and 1.18 % in the crust [21, 22].
An important indicator for the suitability of raw materials for processing in order to obtain pectin is the proportion of protopectin in the total content of pectin substances.
If the indicator is 70-90 %, then such raw materials can be used to obtain pectin. As can be seen from the table, the content of protopectin in all parts of the melon is included in this interval, and in the placenta the proportion of protopectin is 88.31 %. In the crust, this indicator is in the middle of the interval - 78.90 %, which once again confirms its suitability for extracting pectin, given its high yield during melon processing. The content of protopectin in the pulp is close to the lower limit of the interval, which makes it unprofitable for obtaining pectin, but allows it to be used for pectin-containing products.
Gulyabi variety is distinguished by more juicy pulp, the moisture content in it reaches 90.3 %, and the crust is slightly drier - 87.7 %.
The mass fraction of total pectin in the crust is 1.21 %, which, after recalculation for absolutely dry matter, is 9.8 %, which is 1.1 % lower than that of the Myrzachulskaya variety. The proportion of protopectin in the total content of pectin in the crust is 82.65 %, which is higher than that of Myrzachulskaya and makes it no less suitable for pectin production.
The content of pectin in the crust of raw Inzhirnaya melon is the highest of all five samples - 1.67 % due to the lowest moisture content in it 82.4 %, in the absolutely dry matter of this melon pectin is also quite a lot of 9.5 %, which is not significantly inferior variety Gulyabi. Very low pectin content in Gurbek melon rind 7.43 % and especially in Ameri melon rind 6.13 %. However, in the latter variety, almost all pectin is protopectin. The proportion of protopectin in the total content of pectin is 96.25 %, which, taking into account its thick crust, the yield of which when cut is 33.13 %, does not exclude the Ameri variety from the raw material for pectin production.
According to [23], pectins with a degree of esterification of more than 66 % are highly soluble in water (for example, apple), and less than 39.6 % are slightly soluble. According to the degree of esterification, pectins of all varieties of melon are closer to the latter. Pectins with a low content of methoxyl groups contained in melon are able to form sugar-free jelly in the presence of a small amount of polyvalent metal ions. A high content of acetyl groups associated with the hydroxyl groups of pectin substances was found in melon, which significantly worsens them. jelly-forming properties.
There is a problem of processing melons and gourds of early ripeness, due to their poor keeping quality. This aspect is poorly studied in world practice.
In modern market conditions, the issue of production of new high-quality functional food products is one of the most urgent. It provides for the innovative development of agriculture, an accelerated transition to the use of highly productive, resource-saving technologies.
The problems of producing high-quality raw materials, their maximum preservation during storage and processing remain relevant. One of the determining factors for improving the integrated system for the production of fruits and berries is a scientifically based approach to raw materials as an object of storage and processing, the quality of which is determined by the genotype of the variety, environmental, soil-climatic, and technological factors [24].
Confectionery products (CP) are an integral and favorite component of the diet of all categories of the population due to their pleasant sweet taste and attractive aroma. CP consumption in developed countries reaches 18.. .20 kg per person per year.
At the same time, the consumer today has become much more demanding and seeks to enjoy without harm to health. When making a purchase, it weighs its expediency, focuses not only on the price, but also carefully analyzes the information on the composition of each purchased product, which indicates an increase in the culture of consumption of sweets.
The pulp is dominated by fructose, well absorbed by diabetics, nitrogen substances, fiber, iron mineral salts, vitamins B1, B2, C and PP. Watermelon is very rich in carotenoids, which have an antioxidant effect, thanks to which they neutralize the harmful effects of free radicals.
Attention is paid to organic products for baby food. Among the physiological features of early childhood is the immaturity of the gastrointestinal tract (GIT), characterized by high permeability of the intestinal wall, enzyme deficiency, as well as the immaturity of the immune system, lack of antioxidant protection. Children are particularly sensitive to adverse environmental factors during the period of active growth. Studies of the role of the genetic polymorphism of the paraoxonase gene in children have shown that the paraoxonase enzyme is involved in protection against organophospho-rus compounds and oxidative stress, and also inactivates pesticides in the body. Lower levels of the enzyme persist in children until at least seven years of age. This explains the ability of pesticides to influence the development of atopic dermatitis, endocrine, immune, reproductive systems and cognitive impairment in young children [25].
According to the World Health Organization (WHO), about 60 % of deaths in the world are caused by non-communicable diseases. In 2005, an estimated 17.5 million people died from cardiovascular disease (CVD), representing 30 % of all deaths in the world, of which 80 % were from low- and middle-income countries. By 2020, studies show that CVD mortality is expected to increase by 120 % for women and 137 % for men. These results highlight the need to explore opportunities to minimize or eliminate CVD and other non-communicable diseases in developing countries such as Nigeria [26].
Due to the presence of agar and pectin in the recipe ofjelly marmalade, the carbohydrate composition consists of simple sugars (sucrose, glucose, maltose), oligosaccharides (molasses dextrins). It is known that digestible carbohydrates entering the body under the action of enzymes are broken down to glucose and absorbed into the blood, after which they are oxidized for energy, and the excess is converted into glycogen [27].
The glycemic index, as well as the rate of breakdown and stability of carbohydrates, depends on the structure of sweeteners, the conformations of individual monomeric units, and the nature of the relationship between them.
The watermelon fruits were sorted, sized and washed. Then they were cut into cubes and mixed in a coffee grinder with 20 ml or 200 ml of water separately. They were then strained into a closed container and stored in a refrigerator at +4 °C until use. Juices were mixed in various ratios: watermelon juice and rowan juice (90:10, 80:20, 70:30, 60:40 and 50:50).
Fruit gummies serve as an adequate, balanced diet and contain antioxidants such as vitamins C and A, which play an important role in preventing cancer, cardiovascular problems, and improving vision. It has been reported that watermelon has nutritional properties and is rich in antioxidant properties, which can scavenge free radicals, thereby improving the body's antioxidant status. Thus, it is considered appropriate to produce marmalade from these perishable but healthy products in order to make them available throughout the year, as well as to add them to various food products.
The proposed method consists in cooling watermelon fruits to a temperature of +4 °C, then washing and calibrating. Sorted by size and weight, watermelon fruits are peeled, the pulp is cut into cubes, passed through a press and the juice is separated from the seeds. Rowan fruits are cleaned, washed, and juice is prepared. Watermelon juice and prepared rowan juice in various proportions were heated to 95 °C and static for 15 minutes. The marmalade recipe provides for the preparation of sugar-syrup or sugar-syrup-invert syrup, its boiling down to a mass fraction of solids of 85-87 %, cooling the resulting syrup to a temperature of 55-65 °C, followed by the introduction of swollen gelatin, lemon juice pre-soaked in a juice mixture acid, mixed, the resulting mass is cooled to a temperature of 40-50 °C, after which it is cast and aged to obtain the final product - jelly marmalade, which is made from the initial components taken at the following ratio, wt. % (Table 1).
Table 1
Marmalade recipe
Ingredient name Percentage
Sugar -treacle or sugar -treacle- invert syrup 50-60
Gelatin 10-15
Juice mix (watermelon+rowanberry ) 90/10 40-25
Rest 1
The resulting marmalade samples showed a mass fraction of protein 0.40-0.80 %, fat 0.200.40 %, ash content 1.20-1.70 %, crude fiber 0.10-0.30 %, carbohydrates 62, 10-67.16 %, P-carotene 610-1350 ng/100 g and ascorbic acid 9.60-15.40 mg/100 g.) ng/100 g was higher than that of the control sample (610±0.30) ng/100 g. This means that marmalade contains a significant amount of carotenoids
Carotenoids in high amounts can fight diseases such as age-related muscle degenerative diseases, hypercholesterolemia, cardiovascular disease, hypertension, and the occurrence of cancer in humans [27, 28].
In addition, the value of carotenoids indicates that marmalade is a potential source of vitamin A, given that the recommended daily intake is 750 mcg/100 g for a 65 kg adult. The carotenoid content of cooked marmalade was lower than that of some commonly consumed foods such as corn (200 ^g/100 g), psyllium (800 ^g/100 g), cabbage (2000 ^g/100 g) and carrots (12000 ^g/100 g). G). Carotenes are normally converted to retinol (vitamin A) in the small intestine, and its color also makes food more attractive to the eye [29, 30]. The high levels of carotenoids in marmalade may be the result of the red (lycopene) pigment in watermelon [31].
The result of the organoleptic evaluation showed that the prototype marmalade compares very well with imported strawberry marmalade in terms of color, taste, palatability. The 90/10 sample was rated higher than the 50/50 sample. This observation is consistent with the result of chemical analysis, in which a sample with a 90/10 juice ratio showed better nutritional qualities and a longer shelf life. Variation in the ratio of watermelon and rowan juices is shown in Fig. 1, in the context of the evaluated sensory features.
Color
Fig. 1. Organoleptic analysis of watermelon pulp marmalade
The result of microbial contamination tests showed that the total number of aerobic bacteria of 2.0X101 CFU/g for the sample of the prototype marmalade samples was lower than 4.M01 CFU/g of the imported commercial brand. Similarly, the amount of yeast and mold of l.OxlO1 CFU/g respectively for the prototype marmalade was lower than 2.M01 CFU/g for the control. The results showed that no coliforms were found in all samples. This indicates that all samples are safe for human consumption, moreover, the total number of microorganisms does not exceed the allowable limits >105 recommended by the International Commission on Microbiological Characteristics of Foods, ICMSF [32].
Varieties of melon during their biological ripeness have a different pulp structure:
1) spreading, extremely juicy, melting in the mouth;
2) dense, viscous;
3) crispy, watermelon-like;
4) potato, crumbly.
In Kazakhstan, melons of local selection have dense viscous pulp. The type of spreading, melting in the mouth pulp is due to its high juiciness and cell maceration. The crunchy watermelon-like pulp of melons has a highly porous structure and a more developed coarse conductive system. The pulp has many intercellular spaces with a large number of air bubbles, which also create elasticity, which makes these melons "crunchy" when eaten fresh.
In the fruits of melons and gourds, there are three systems of feeding vessels:
1) passing through the center of the fetus;
2) along its periphery;
3) in the middle of cow pulp. They are interconnected by the ends of the branches [33].
For an accelerated quantitative and qualitative assessment of the degree of microbial contamination of finished products, the determination was carried out on an automated express system, the BakTrak device. This method makes it possible not only to determine the number of microorganisms in the sample, but also to determine the level of their activity, which is decisive in the process of food spoilage by microorganisms [34].
Microbiological analysis of samples by the standard method was carried out based on the SanPiN 42-123-4940-88 standards according to standard methods immediately after manufacture and periodically during storage. The total number of mesophilic aerobic and facultative anaerobic microorganisms per 1 g (MAFAM), the titer of bacteria of the Escherichia coli group (ECG), the presence of pathogenic microorganisms, incl. Salmonella in 25 g and pathogenic staphylococcus in 1 g, the number of yeasts and micromycetes in 1 g [35-40].
In the course of the study, part of the sugars included in the formulation was replaced by HFS, which made it possible to save up to 70 % of sugar. All types of raw materials must meet the requirements of regulatory documentation. For the agar use, it is provided for soaking in water in the ratio of agar: water - 1:40 for 30.40 minutes 3 MPa). After complete dissolution of the agar, the prescribed amount of glucose-fructose syrup is added, which is necessary for the preparation of jelly marmalade, and mixed. After complete mixing of the mass, melon pulp is added in the form of a homogeneous ground mass. Stirred and boiled in a vacuum cooker. To a mass fraction of solids 73-75 %. Next, the syrup is filtered, rowan juice is added, brought to a solids content of 60 %, and sent to a tempering machine with a temperature of 60 °C. Next, marmalade is cast into molds and left at room temperature until solidified, for 80 minutes, the moisture content in finished products is 18 %. Then they are sent for drying in a ventilated oven at a temperature of 40 °C within 20 min.
The chemical composition of the raw material, in our case, melon puree, is shown in Table 2.
Table 2
The chemical composition of melon puree
Nutrient Quantity
Norm*
% of norm in 100 g
% of the norm in 100 kcal
100 % normal
Calories Proteins Fats
337 kcal 0.04 g 0.01 g
1684 kcal 76 g 56 g
20 % 0.1 %
5.9 %
500 g 190000 g 560000 g
The energy value of jelly -melon marmalade is 337 kcal.
Jelly-melon marmalade has an increased nutritional value, especially in the content of sodium, potassium, calcium, phosphorus, vitamins C and E, and neurovitamins.
Dyes and flavors are excluded from the recipe, as marmalade acquires color due to the content of melon juice and puree, turning into a jelly mass.
In the proposed method, carbohydrate-containing raw materials, namely sugar, are replaced by stevioside, which makes it possible to use products for people suffering from diabetes.
An increase in the dosage of melon juice over 250 kg/t leads to an increase in the content of reducing sugars, the consistency of finished products becomes loose, a decrease in its dosage to less than 214 kg/t leads to a deterioration in its consistency, it becomes glassy, nutritional value decreases, and stickiness increases.
Microbiological indicators of the finished product are summarized in Table 3.
The amount of yeast and mold 1.0*10' CFU/g respectively for the prototype marmalade was lower than 2.1*10* CFU/g for the control. The results showed that no coliforms were found in all samples. This indicates that all samples are safe for human consumption, moreover, the total
number of microorganisms does not exceed the acceptable limits of >105 recommended by the International Commission on Microbiological Characteristics of Foods, ICMSF [41].
Table 3
Microbiological indicators of melon -jelly marmalade
Name of indicator Indicator value
coli Missing
Causative agents of botulism Missing
ECG Missing
Salmonella in 25 cm3 of product Missing
Yeast, CFU /g no more than 50
Mold, CFU /g no more than 50
According to organoleptic indicators, the products must meet the requirements given in Table 4.
Table 4
Organoleptic characteristics of jelly marmalade from pulp and melon juice Name of indicator Index
Taste, smell, color Taste and smell characteristic of melon, color from light yellow to dark yellow
Consistency Gelatinous, lingering consistency is allowed for marmalade on agaroid, gelatin, modified starch
Form For shaped - correct, with a clear contour without deformation. Slight sags are allowed, fuzzy
edges are allowed for marmalade by casting
The moisture content of marmalade, in accordance with the indicators of regulatory documents, does not exceed 20 %, the mass fraction of reducing substances is not more than 20 %. The mold content according to the normative documents for jelly marmalade is 100 g/cm3, in our marmalade it does not exceed 50 g/cm3.
Marmalade should be stored at a temperature of +15 °C without exposure to direct sunlight. Shelf life without loss of quality under these conditions is 1.5 months.
Methods for processing and mechanization of the preparation of watermelons and melons are described in [42-50].
There are plans to expand the scope of the study. Processing of fruits of melons and watermelons for long-term storage products with the preservation of all useful properties.
Restrictions may be the seasonality of raw materials and low keeping quality. The condition of applicability is the compliance of raw materials with normative documents on the content of nitrites. With a larger quantity, finished products are quickly spoiled. The fruits must be whole, without dents. Overripe fruits should not have pronounced pungent odors.
The production of food products based on melons and gourds is limited by the duration and temperature regime of heat treatment. The increase in time and temperature during the cooking of juices and mashed gourds has a negative impact on the organoleptic indicators of the quality of finished food products.
4. Conclusions
All varieties of melons sold on the territory of the Republic of Kazakhstan and melons of domestic selection were studied. The works of employees of the Almaty Technological University on the processing of melon into blended juices, marmalade, pectin, etc. are given. The results of the work on the development of marmalade from the pulp and juice of watermelon and melon fruits are presented.
Watermelon and rowan extract marmalade is highly nutritious and good for human consumption. In the production of marmalade, technology should be followed, marmalade should be produced in safe, hygienic conditions, watermelon should be brought to a temperature of +4 °C before processing, and watermelon juice should be stored in sealed containers and kept in a refrigerator at a temperature of 4±4 °C for no more than 24 hours. Further research work will be done to investigate the preservative effect of natural antioxidants alone or in combination with each other on marmalade samples.
An analysis of the results of the studies carried out allows to note that the obtained blended juices are distinguished by a richer vitamin composition in terms of quality and quantity. Therefore, the taken raw materials-enrichers make it possible to obtain drinks enriched with vitamins of a given qualitative composition. This is of no small importance, because according to research by scientists it has been established that vitamins are involved in the regulation of the most important processes in the body only in the form of coenzymes (the vitamins themselves are inactive). Therefore, the processes in which vitamins are involved are complex and involve not one, but two or even several (up to 6) vitamins.
An overview of the technology for processing melons and gourds is given: peeling, pulp extraction, separating seeds for technical and food needs. The results of research and development of mechanisms and devices for processing watermelons, pumpkins and melons are presented. The theoretical foundations of research and the evidence base are given. Criterial equations are derived for all processes of processing melons and gourds.
The technologies developed by the authors for the processing of gourds for food are presented.
Conf lict of interest
The authors declare that there is no conflict of interest in relation to this paper, as well as the published research results, including the financial aspects of conducting the research, obtaining and using its results, as well as any non-financial personal relationships.
Funding
The study was performed without financial support.
Data availability
Data will be made available on reasonable request.
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