Fresh Beetroot Research Articles

Evaluation of energy efficiency and quality parameters by drying beets with a refractive window (Betavulgaris)

This study evaluated the energy efficiency associated with drying by refractance window™ and its effect on the physical and chemical properties of beetroot in two different physical states, in semisolid (puree type) and solid (slices) were compared. The refractance window™ drier was compared to a tray dryer at 70 °C on the food surface. The drying time was calculated through the kinetics in both dryers in both physical states of the beetroot determining the moisture content at the beginning and the end of the drying process after which water activity and color retention were determined. Total polyphenol and flavonoid contents respectively, and antioxidant activity were evaluated. Overall energetic efficiency for both dryers was calculated. The beetroot dried in semisolid state using the refractance window™ technology retained color and showed no differences when compared with fresh beetroot. No significant differences in total polyphenol content and total flavonoid content when compared with the fresh sample after application of the refractance window™ were found. The overall energetic efficiency was higher after using refractance window™ drying in beetroot in the two physical states and produced greater retention of quality parameters when compared with the tray dryer.

Effect of Preparation and Drying Techniques on the Physicochemical, Functional and Nutritional Properties of products from Beetroot (Beta Vulgaris L.) varieties

Beetroot (Beta vulgaris L.) is rich in biologically active compounds. This study aimed to assess how different methods of preparation and drying affect the physical, chemical, functional, and nutritional properties of iron-rich beetroot powder. Two beetroot varieties, Detroit Dark Red (DetR) and Crimson Globe (CrimG), were processed using three drying techniques: sun drying (SD), oven drying (OD), and freeze drying (FD), with both boiled and fresh beetroots. The properties evaluated in the study included water activity, color, total phenolics and flavonoids, oxalate content, and mineral content. The results showed significant (p<0.05) differences in these properties between the dried and fresh samples. Notably, drying increased calcium, zinc, and phosphorus levels while decreasing the iron content. Boiling followed by sun drying was the best method for retaining iron, particularly for the CrimG variety. The study suggests that drying can help preserve or even enhance the physicochemical properties and micronutrient content, especially iron while reducing phytochemical levels affecting iron absorption. These findings are important for developing iron-rich beetroot products to improve dietary iron intake, especially for adolescent children.

Beetroot juices as colorant in plant-based minced meat analogues: Color, betalain composition and antioxidant activity as affected by juice type

The aim of this work was to study the suitability of the application of beetroot juices (obtained from fresh beetroot, cooked beetroot, beetroot powder and commercial beetroot juice) as colorants in the development of meat analogues, as well as their antioxidant properties. Fresh beetroot juice showed the highest betalain content (119.53 mg betanin/100 ml and 48.27 mg vulgasanthin I/100 ml) and commercial juice the lowest (49.40 mg betanin/100 ml and 7.21 mg vulgasanthin I/100 ml). Juices from fresh and cooked beetroot showed ABTS, FRAP and FIC values higher than values obtained for commercial juice (ascorbic acid added). Textured soy protein with cooked beetroot juice or with commercial juice showed the same appearance that of minced beef and pork meat, respectively, which is in accordance with their hue values and reflectance spectra. The attractive red color of betalains and their stability at the pH value of meat analogues make beetroot juices ideal for their application as colorants in meat analogues.

Drying kinetics and quality assessment of refractance window dried beetroot

AbstractThin‐layer drying of red beetroot having slice thicknesses of 0.5, 1, and 1.5 mm was carried out using a solar‐assisted continuous refractance window dryer at 75, 80, and 85°C drying temperatures for 30, 45, and 60 min. The drying kinetics including moisture ratio, drying rate, and moisture diffusivity was observed to understand the drying behavior of beetroot. The moisture ratio was fitted to the drying models for thin‐layer modeling of the beetroot drying. The drying operation reduced the firmness and water activity of the fresh beetroot; however, the antioxidant properties of dried beetroot increased with drying treatment. The minimum alteration was observed with a color difference and hue angle of dried slices. Process optimization was carried out to obtain the ideal drying conditions, which indicated the use of a dryer at 85°C temperature, 0.5 mm slice thickness, and 60 min exposure time with a desirability value of 0.874.Practical applicationsFourth‐generation drying technology refractance window drying dried the beet root slices without case hardening and improve its antioxidant properties. Dried beetroot contains carotenoids, vitamins, nitrates, flavonoids, and various minerals that have antioxidant, anti‐inflammatory, anticarcinogenic, and hepato‐protective activities. Dried beetroot flakes or powder is useful for the development of different functional foods that have anti‐diabetic, cardiovascular disease lowering, hypertensive, and wound healing benefits.

Antioxidant Capacity, Nitrite and Nitrate Content in Beetroot-Based Dietary Supplements.

Due to the high content of bioactive substances, beetroot and its preserves might be a valuable constituent of a diet. Research into the antioxidant capacity and content of nitrate (III) and (V) in beetroot-based dietary supplements (DSs) worldwide is limited. The Folin-Ciocalteu method, CUPRAC, DPPH, and Griess methods were used to determine total antioxidant capacity, total phenolic content, nitrites, and nitrates content in fifty DSs and twenty beetroot samples. Moreover, the safety of products was evaluated because of the concentration of nitrites, nitrates, and the correctness of labelling. The research showed that a serving of fresh beetroot provides significantly more antioxidants, nitrites, and nitrates than most daily portions of DSs. Product P9 provided the highest dose of nitrates (169 mg/daily dose). However, in most cases, the consumption of DSs would be associated with a low health value. The acceptable daily intake was not exceeded in the cases of nitrites (0.0015-0.55%) and nitrates (0.056-48%), assuming that the supplementation followed the manufacturer's recommendation. According to European and Polish regulations, 64% of the products tested did not meet all the requirements for labelling food packaging. The findings point to the need for tighter regulation of DSs, as their consumption might be dangerous.

Investigation of the Antimicrobial Properties of Beetroot–Gelatin Films Containing Silver Particles Obtained via Green Synthesis

Silver nanoparticles are produced using various physical, chemical or physicochemical methods. Simple low-cost nontoxic environmentally friendly, or “green”, chemistry methods are important, especially for their invasive application in the medicine and food industries. Silver-nanoparticle-enriched biocompatible films were produced at room temperature from fresh beetroot juice, AgNO3 and gelatin–water solution using the photoreduction method. The optical, morphological and structural characteristics of the experimental samples were analyzed using UV-VIS, XRD and SEM techniques. The antimicrobial activity of newly produced films was investigated using the agar diffusion method. The synthesis of nanoparticles was approved their characteristic LSPR peaks in the UV-VIS absorbance spectra. According to the XRD patterns of the films, these nanoparticles were assigned to the cubic phase of metallic Ag. It was found that the antimicrobial activity of the silver nanoparticles in the beetroot–gelatin films might be effective; however, it depends on the silver ion concentrations used for the production of these films and on the medium’s pH.

ОРГАНИЗАЦИЯ ХРАНЕНИЯ ОВОЩЕЙ В ЛЕЧЕБНО-ИСПРАВИТЕЛЬНОМ УЧРЕЖДЕНИИ СИСТЕМЫ ФСИН

The issues of the organization of rational storage of food products supplied for the needs of the penal system for the purpose of food supply of the special agent are considered. Much attention is paid to the development of a warehouse economy in the direction of storing plant-growing products included in the medical nutrition standards of people in medical and correctional institutions. To study the rational storage of vegetable products received for the needs of the penal system, the entire system of the warehouse management of the medical institution was analyzed in order to identify possible storage of vegetable products for a longer time than prescribed in regulatory legal acts by reducing natural loss. The economic efficiency of the warehouse economy is analyzed on the example of a typical medical correctional institution operating in one of the territorial bodies of the Federal Penitentiary Service of Russia in order to possibly find money savings associated with the process of storing vegetables. The main directions of the warehouse economy functioning are considered. The general characteristics of the warehouses of the medical and correctional institution are given. The volumes of harvesting vegetables for 2019-2021 in a medical and correctional institution are characterized. The norms of natural loss for such vegetable products as: late fresh carrots, fresh food potatoes (late), fresh beetroot (late), fresh white cabbage (late) are calculated. It follows from the analyzed directions that the largest storage areas of vegetable products are occupied under potatoes, since in accordance with regulatory legal acts, the name of this product is included in the catering of the special ingredient in a larger volume and it is advisable to keep these products fresh for a long time, while avoiding the purchase of fresh harvest at a more expensive price. A similar analysis was carried out for vegetable products included in the norms of food security. The dynamics of changes in natural loss by month in percentage terms of vegetable losses is shown. Ways to reduce natural attrition in medical and correctional institutions of the Federal Penitentiary Service of Russia are outlined.

Different Methods of Betalain Extraction from Red Beetroot (Beta vulgaris L.) for Preparation of Solid Food Colour and Preparation of Beetroot Leather

An experiment was conducted at the Department of Horticulture, Naini Agricultural Institute, Sam Higginbottom University of Agriculture Technology and Sciences, Prayagraj, Uttar Pradesh during the year 2021-2022. This experiment was conducted to assess the best extraction method for highest concentrated Betalain formulation. The best betalain extraction method was obtained from freezing – ground and squeezing method, which had highest betalain extract (530m/kg fresh beetroot) with pH 5.08. Altogether 11 treatments were taken for both betalain powder and beetroot leather preparation. Combination of Freezed-Betalain and 3g corn starch (T9) was found best for betalain powder prepration in terms of physio-chemical properties, pH and organoleptic test viz. color and appearance, texture and taste. The combination of beetroot pulp 860g + 1g salt + 1g citric acid + 200g sugar + 4g maltodextrin powder was best for preparation of beetroot leather in terms of physio-chemical properties and organoleptic taste. The powder and leather samples were stored both at ambient temperature (28 ± 5 °C) and refrigerated condition (5 ± 2 °C) for 60 days. Beetroot leather performed well under cold temperature than the room temperature and on the other, betalain powder performed better in room temperature. The maximum Benefit cost ratio (2.46) was found in T9 (Freezed Betalain + 3g corn starch).

Fresh and Stored Sugar Beet Roots as a Source of Various Types of Mono- and Oligosaccharides.

Although sugar beets are primarily treated as a source of sucrose, due to their rich chemical composition, they can also be a source of other carbohydrates, e.g., mono- and oligosaccharides. The study focused on both fresh beet roots and those stored in mounds. Our studies have shown that, in addition to sucrose, sugar beet tissue also comprises other carbohydrates: kestose (3.39%) and galactose (0.65%) and, in smaller amounts, glucose, trehalose and raffinose. The acidic hydrolysis of the watery carbohydrates extracts resulted in obtaining significant amounts of glucose (8.37%) and arabinose (3.11%) as well as xylose and galactose and, in smaller amounts, mannose. An HPSEC liquid chromatography study of the molecular mass profile of the carbohydrate compounds present in the beet roots showed alongside the highest percentage (96.53–97.43%) of sucrose (0.34 kDa) the presence of pectin compounds from the araban group and arabinoxylooligosaccharides (5–9 kDa) with a percentage share of 0.61 to 1.87%. On the basis of our research, beet roots can be considered a potential source of carbohydrates, such as kestose, which is classified as fructooligosaccharide (FOS). The results of this study may be helpful in evaluating sugar beets as a direct source of various carbohydrates, or as a raw material for the biosynthesis of fructooligosaccharides (FOS) or galactooligosaccharides (GOS).

The influence of different drying methods on the quality attributes of beetroots

Beetroot is recognized as a health-promoting vegetable due to its abundant source of bioactive compounds. Drying methods significantly influence the quality of products. Therefore, it is important to choose a suitable drying method to obtain high quality of dried beetroots. The aim of this research was to investigate the influence of different drying methods on the quality attributes of beetroots. Fresh beetroots were dehydrated by freeze drying (FD), heat pump drying (HPD), vacuum drying (VD), microwave drying (MD) and microwave vacuum drying (MVD), respectively. The drying time, final moisture content, rehydration ratio, color, microstructure, betalain content and total flavonoids content of beetroots prepared by different drying methods were analyzed. The results showed that MVD and MD were superior to VD, HPD and FD in terms of drying time. The drying time (0.77±0.03 h) of MD was reduced by 97.40 % compared with FD, which was only 9.83 % of VD and 11.27 % of HPD. No significant differences in the final moisture content among beetroots dried using different drying methods were observed. Beetroots dried by FD showed the most desirable color and porous structure. Besides, beetroots dried by MVD exhibited the largest rehydration ratio, while the lowest rehydration ratio appeared in the beetroots obtained using MD. In addition, beetroots prepared by HPD illustrated the highest contents of betacyanin, betaxanthin and total flavonoids, which were 5.48±0.03 mg/g, 2.40±0.02 mg/g and 24.71±0.47 mg rutin equivalent/g, respectively. These results identify that it is difficult to achieve the best quality dried beetroots using a single drying method. Therefore, considering the quality attributes, the combined drying method (HPD+MVD) would be a very promising alternative method for obtaining dehydrated beetroots

Sensory attributes, bioactive compounds, antioxidant activity and color values of jam and candy developed from Beetroot (Beta vulgaris L.)

Beetroot is a root vegetable with abundant bioactive compounds like phenols, flavonoids and betalains that give the beetroot a characteristic colour. The present study was conducted to develop preserved functional foods from fresh beetroot and analyze sensory attributes, physico-chemical properties, nutritional parameters, bioactive compounds, antioxidant activity and color values. Total soluble solids and acidity contents of raw beetroot, beetroot jam and candy was found to be 10.72° Brix and 0.06 %, 69.03 °Brix and 0.72 % and 69.43° Brix and 0.12 %, respectively. The TSS content of jam and candy was found to be 55.77±0.09 and 66.50±0.19, respectively. Total phenols, flavonoids, betalains and antioxidant activity of jam and candy were found to be 82.58 and 98.94 mg GAE/100g, 47.85 and 45.51 mg QE/100 g, 267.73 and 357 mg/100g and 35.43 and 42.13 %, respectively. The L* value indicating the lightness of a product decreased for beetroot jam as opposed to L* value of beetroot candy, which increased compared to raw beetroot. The a* value revealing the redness of jam increased whereas redness of candy decreased compared to raw beetroot. The present study indicated that; beetroot could be used for the preparation of jam and candy with good sensorial quality, which has a high market potential.

Study on the effect of intermittent microwave drying conditions on the bioactive compounds and antioxidant capacity of beetroots

The object of this research was the beetroots prepared by intermittent microwave drying at different conditions. The paper aimed to investigate the influence of intermittent microwave drying conditions (power density, microwave gap ratio and slice thickness) on the bioactive compounds and antioxidant capacity of beetroots. A microwave drying system SAM-255 (CEM Corporation, USA) was used to intermittent microwave drying of fresh beetroots. The effect of different power densities (1.0, 1.5, 2.0, and 2.5 W/g), microwave gap ratios (1, 2, 3, and 4) and slice thicknesses (2, 4, 6, and 8 mm) on the bioactive compounds and antioxidant capacity of beetroots were investigated. Colorimetric methods were used to determine contents of betalains, total phenolic and total flavonoid, and antioxidant capacity of dried beetroots. The ascorbic acid content was determined using 2,6-dichloroindophenol titration method. Results showed that power density, microwave gap ratio and slice thickness significantly affected the drying time, bioactive compounds and antioxidant capacity of beetroots. The drying time decreased with the increasing of power density, while increased significantly with the growth of slice thickness and microwave gap ratio. The shortest drying time (35.4±2.6 min) of beetroots was occurred at microwave gap ratio of 2. The content of betacyanins was found to be the highest in the dried beetroots with thickness of 2 mm. The beetroots with slice thickness of 2 and 4 mm showed the highest betacyanins content. Moreover, the highest content of ascorbic acid (240.00±2.32 mg/100 g) and total flavonoid (14.52±0.06 mg rutin equivalent (RE)/g) was appeared at power density of 2.0 W/g, while the content of total phenolic to be highest (12.54±0.13 mg gallic acid equivalent (GAE)/g) at slice thickness of 6 mm. For the antioxidant capacity of dried beetroots, the 1,1-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity reached to the highest value of 6.43±0.03 mg trolox equivalent (TE)/g at power density of 2.5 W/g. While the highest values of ferric-reducing antioxidant power (FRAP) (15.47±0.10 mg TE/g) and 2,2′-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging activity (25.31±0.30 mg TE/g) at microwave gap ratio of 2. It was found that ABTS radical scavenging ability and FRAP were related to the presence of reductions including betalains, ascorbic acid, and total flavonoid in beetroots. The most effective condition for intermittent microwave drying of beetroots were microwave gap ratio of 2, power density of 2.0 W/g, and slice thickness of 4 mm, leads to a better preservation of bioactive compounds and high antioxidant capacity.

Preparation And Quality Evaluation Of Sugar And Honey Based Beetroot Candies

Beetroot is notable for its sweetness, high sugar content, but is very low in calories. Despite its nutritional value, many people refuse to consume it because of its earthy flavor. So, the study was conducted in the laboratory of Pokhara Bigyan Tatha Prabidhi Campus from September 2020 to December 2020 to prepare sugar and honey-based beetroot candy and make a comparative study on their qualities. By following the preliminary operations, fresh beetroot was candied by using honey and sugar syrup of 30 °Brix. Within certain days of boiling and draining of syrup, a gradual increment of TSS was obtained up to 70 °Brix and was finally dried at 55±3 ℃. The moisture content (26.18±0.58), crude fat (0.52±0.01), crude protein (1.60±0.14), crude fiber (2.39±0.19), titratable acidity (0.23±0.05), pH (5.82±0.02), reducing sugar (38.07±0.28), color (6.7±0.24), flavor (6.3±0.18), texture (6.65±0.25), taste (7.10±0.22), appearance (7.17±0.27) and overall acceptability (7.10±0.24) was recorded more in honey-based candy while carbohydrate (70.01±0.76) and ash (1.75±0.13) was recorded more in sugar-based candy. The total soluble solid was obtained equally in both sugar and honey-based candy which was 70 °Brix. The honey-based candy was better in nutritional, chemical and sensory attributes so it is suggested to use honey as a syrup instead of sugar syrup.

Influence of vacuum microwave drying parameters on the physicochemical properties of red beetroots

In recent years, the consumption of red beetroots has increased significantly due to its good taste, high nutritional value and abundant active compounds. Red beetroot is prone to spoilage due to its high moisture content, making it perishable. Vacuum microwave drying is a gentle drying method by inducing fast water evaporation from food products at low temperature, which can improves the product quality. The objective of this study was to investigate the effects of vacuum microwave drying parameters, including microwave power (500, 1000, and 1500 W) and vacuum degree (50, 70, and 90 KPa), on the physicochemical properties (drying time, rehydration ratio, color change, and contents of betalain and total phenolic) of red beetroots. The results showed that microwave power and vacuum degree had significant effects on the physicochemical properties of red beetroots. All the red beetroots after vacuum microwave drying had higher lightness (L*), lower redness (a*) and yellowness (b*) than that of fresh red beetroots. The drying time, rehydration ratio, betacyanin content and betaxanthin content of red beetroots decreased significantly with the increase of microwave power (P < 0.05), while the rehydration ratio, color parameters (a*, b*, and chroma values), betacyanin content and betaxanthin content of red beetroots significantly increased with the increase of vacuum degree (P < 0.05). Compared with other microwave powers, the red beetroots dried at 500 W showed longer drying time, higher rehydration ratio, more yellowish hue, and higher contents of betacyanin and betaxanthin. The lowest values of total color difference (∆E) and hue angle (H°) of dried red beetroots were obtained at microwave power of 1500 W. The dried red beetroots obtained at 90 KPa had the shortest drying time, the highest rehydration ratio, the best color, and the highest contents of betacyanin and betaxanthin. Meanwhile, the red beetroots dried at 50 KPa had the highest total phenolic content (12.47 ± 0.09 mg GAE/g). Based on the physicochemical properties of red beetroots, vacuum microwave drying at low microwave powers and high vacuum degree appears to be a suitable method for drying red beetroots.

VITAMIN C, TOTAL PHENOLS AND ANTIOXIDATIVE ACTIVITY OF ORGANICALLY GROWN RED BEETROOT (BETA VULGARIS SSP. RUBRA) AND EFFECT OF PROCESSING

The demand for organic food is rising since consumers want food from reliable, highest quality sources originating from the environment, undisturbed by cultivation and processing. It is necessary to determine to what extent there is a scientific basis for the claims that organic food is of high quality. In this study, beetroot from an organic production system originating from 6 certified organic food producers from different geographic locations was examined. The organic beetroot samples were processed by pasteurization at 700 C and 900 C into beet juice or by drying at 550 C. The following samples were tested and compared: fresh beetroot, pasteurized beet juice and dried beetroot slices. The concentration of vitamin C, level of total phenol compounds (TPC) and antioxidative activity (TAA) in beetroot were influenced by the geographic origin and the applied processing method. The highest degradation for all analysed parameters was found in the samples treated by drying or pasteurisation at 90ºC. The lowest losses of studied phytochemical components were observed during juice pasteurisation at 700C. The correlation coefficient between TPC and TAA was high and significant (r2 = 0.966).

Research of physicochemical properties and antioxidant activity of beetroots as affected by vacuum microwave drying conditions

The object of research is the beetroots, dried by vacuum microwave drying at different conditions. Physicochemical properties and antioxidant activity of beetroots were studied using vacuum microwave drying at different microwave power (500, 1000, and 1500 W), vacuum degree (–0.05, –0.07, and –0.09 MPa) and sample thickness (2, 4, and 6 mm). A colorimeter was used to evaluate the color quality of beetroots. Colorimetric methods were used to determinate contents of betalain, ascorbic acid and total flavonoid, and antioxidant activity (ferric reducing antioxidant power assay) of beetroots. Results showed that the drying time decreased with increasing microwave power and vacuum degree, while increased significantly with the increase of sample thickness. The lightness (L*) of dried beetroots was higher than that of fresh beetroots. The values of redness (a*) increased with the increase of vacuum degree. The values of yellowness (b*) increased with the growth of vacuum degree and microwave power, while reduced as the sample thickness added. The total color difference (∆E) of dried beetroots reduced with increasing vacuum degree, and displayed the lowest value (5.95) at a vacuum degree of –0.09 MPa as compared to fresh beetroots. The content of betacyanin, betaxanthin and ascorbic acid displayed a declining tendency with the growth of microwave power, while increased with the increase of vacuum degree. And the total flavonoid content of beetroots illustrated a decreasing tendency with the increase of vacuum degree, microwave power and sample thickness. The ferric reducing antioxidant power (FRAP) of dried beetroots decreased significantly with the increase of microwave power, and showed the highest value (14.70 mg trolox equivalents/g) at a microwave power of 500 W. The most favorable conditions for vacuum microwave drying of beetroots were microwave power of 500 W, vacuum degree of –0.09 MPa and sample thickness of 2 mm. It leads to better physicochemical properties of bioactive compounds and higher antioxidant activity of dried beetroots. The dried beetroots can be used as functional foods and value-added food products.

Antimicrobial and Anticancer Effect of Bioactive Compounds in Red Beet Roots التأثير المضاد للنشاط الميکروبى و المضاد للسرطان للمواد الفعاله فى جذور البنجر الأحمر.

This research was carried out to study the bioactive compounds which found in red beet roots as antimicrobial activity and as anticancers in the lung and breast . Red beet roots were used and a set of technological treatments (drying, blanching than drying and freeze-drying) were carried out to choose the most appropriate treatments to reduce the loss of bioactive substances. Chemical properties, minerals and active substances were estimated for each of the previous treatments. Results showed that the drying treatment of red beet roots exhibited the lowest rates of loss in chemical composition and active substances. Methanolic extract of fresh red beet roots and other treatments of red beet roots as antimicrobial activity of some types of bacteria, fungi and yeasts, and the results showed positive effects on bacteria and yeast. Also, the effect of the methanolic extract of fresh beet roots and other treatment of red beet roots were examined as anticancers on the carcinogenic cells of the lung and breast.The results showed that the IC50 obtained from fresh and dried red beet roots extract were 352, 227, 242 and 321 µg/ml on both of breast and lung cancer cells, respectively. Therefore, the study recommends that red beet roots could be added in many foodstuffs to reduce the incidence of cancer.

Effect of Composition and Processing Conditions on Selected Properties of Potato-Based Pellets and Microwave-Expanded Snacks Supplemented with Fresh Beetroot Pulp

The aim of this study was to evaluate the influence of the addition of fresh beetroot pulp in amounts from 2.5 to 30.0 g/100 g, as well as variable screw speeds (60, 80, 100 rpm) on the chemical composition, water absorption, water solubility index, density, expansion rate, and texture of potato-based pellets and expanded snacks. Their protein and starch structure was analyzed using the Fourier-transformed infrared (FTIR) spectroscopy. The snack pellets were made at a moisture content of 33 g/100 g of blends using a single-screw extruder equipped with a plasticizing unit having a length-to-diameter ratio (L/D) of 18. Processing temperature ranged from 65 to 105°C. The ready-to-eat snacks were expanded using microwave treatment (750 W, 40 s). Fresh vegetable pulp addition raised the protein content. The extrusion-cooking caused an increase in the content of insoluble dietary fiber and water absorption index of the pellets. In contrast, the microwave treatment reduced values of these parameters in expanded products and decreased the insoluble dietary fiber content of the expanded snacks. The addition of fresh beetroot pulp diminished the expansion ability and increased the content of β-sheet proteins. Additionally, an increase in the content of β-turn and β-sheet protein fractions was observed at the expense of random coil structure. This indicates that the protein structure underwent some form of ordering as the molecular interactions of the proteins intensified. The highest fraction of β-structures and the smallest content of random coil were observed when 80 rpm was applied during processing. It seems to be the most efficient screw speed in processing fresh beetroot pulp-supplemented snack pellets. Application of a fresh beetroot pulp as an additive in microwave expanded snacks made it possible to obtain products with an increased amount of fiber and a reduced fat content as an attractive and healthy alternative to deep-fried snacks.

Impact of Cold Storage on Bioactive Compounds and Their Stability of 36 Organically Grown Beetroot Genotypes.

In order to exploit the functional properties of fresh beetroot all year round, maintaining the health-benefiting compounds is the key factor. Thirty-six beetroot genotypes were evaluated regarding their content of total dry matter, total phenolic compounds, betalain, nitrate, and total soluble sugars directly after harvest and after cold storage periods of one and four months. Samples were collected from two field experiments, which were conducted under organic conditions in Southwestern Germany in 2017 and 2018. The outcome of this study revealed a significant influence of genotype (p < 0.05) on all measured compounds. Furthermore, significant impacts were shown for storage period on total dry matter content, nitrate, and total phenolic compounds. The medians of nitrate content based on the genotypes studied within the experiment ranged between 4179 ± 1267–20,489 ± 2988 mg kg−1 DW (dry weight), and that for the total phenolic compounds varied between 201.45 ± 13.13 mg GAE 100 g−1 DW and 612.39 ± 40.58 mg GAE 100 g−1 DW (milligrams of gallic acid equivalents per 100 g of dry weight). According to the significant influence of the interactions of storage period and genotype on total soluble sugars and betalain, the decrease or increase in the content of the assessed compounds during the cold storage noted to be genotype-specific. Therefore, to benefit beetroots with retained quality for an extended time after harvest, selection of the suitable genotype based on the intended final use is recommended.

Effect of microwave-assisted drying methods on the physicochemical properties of beetroots

In this study, fresh beetroots were dried by five different microwave-assisted drying methods, including high-power microwave drying followed by low-power microwave drying (HMD—LMD), high-power microwave drying followed by hot-air drying (HMD—HD), hot-air drying followed by low-power microwave drying (HD—LMD), high-power microwave drying followed by vacuum drying (HMD—VD), and vacuum drying followed by low-power microwave drying (VD—LMD). After drying, moisture content, color, and rehydration ratio as well as betalains and total phenolic contents of the dried beetroots were investigated. The drying time of each microwave-assisted drying method was also investigated. As for drying time, HMD—LMD lasted 46.0 min compared to VD—LMD which lasted 308.0 min. HD—LMD took 185.0 min less than HMD—HD (230.0 min) and HMD—VD (265.0 min). The beetroots obtained by VD—LMD showed the best color appearance, the highest betalain content and total phenolic content, but its drying time was the longest and rehydration ratio was the lowest. The beetroots obtained using HD—LMD showed the highest rehydration ratio. Considering physicochemical properties of dried beetroots and economics, HD—LMD is a recommended and suitable drying method.