Dehydration of red beet root (Beta vulgaris) by hot air drying: Process optimization and mathematical modeling

Sustainable production of naturally colored extruded breakfast cereals from blends of broken rice and vegetable flours

There is a growing demand for practical and healthy food products. Obtaining naturally colored breakfast cereals with the incorporation of functional ingredients is a promising alternative for consumers that are looking for healthiness. This study aimed to evaluate the feasibility of using vegetable flours, rich in pigments, to obtain naturally colored breakfast cereals through thermoplastic extrusion. Vegetables considered "unsuitable for the retail market", classified as "type B", were used to prepare different flours from carrot (CF), spinach (SF) and beetroot (BF). Extrudates were produced from a mixture of 90% broken rice (BR) and 10% vegetable flour (CF, SF or BF). Besides giving the extrudates a natural color, the use of vegetable flours also provided nutritional and functional enrichment due to increased mineral, protein, lipid, fiber and phenolic compound contents, and greater antioxidant capacity. However, some of these components, such as fibers, affect extrudate physical structure and technological characteristics, evidenced by reduced expansion, hardness, paste viscosity and greater interaction with water present in milk under consumption conditions. In general, the evaluated flours proved to be an alternative for imparting a natural color to extruded breakfast cereals, in addition to positively contributing to their nutritional and functional value.

Multipronged Approach to Profiling Metabolites in Beta vulgaris L. Dried Pulp Extracts Using Chromatography, NMR and Other Spectroscopy Methods

Beetroot (Beta vulgaris L.) is known for being a rich source of phytochemicals, minerals and vitamins. This study aims to show how the combination of extraction/chromatography/mass spectrometry and NMR offers an efficient way to profile metabolites in the extracts of beetroot. Such combination may lead to the identification of more nutritional or medicinal compounds in natural products, and it is essential for our ongoing investigation to study the selective adsorption/desorption of these metabolites' on/off nanoparticles. The aqueous and organic extracts underwent analyses using UV-vis spectroscopy; GC-MS; LC-MS; 1H, 13C, 31P, TOCSY, HSQC, and selective TOCSY NMR experiments. Polar Extract: The two forms of betalain pigment were identified by UV-vis and LC MS. Fourteen amino acids, sucrose, and other compounds, among which is riboflavin, were identified by LC-MS. Two-dimensional TOCSY showed the spin coupling correlations corresponding to some of these compounds. The HSQC spectrum showed 1H/13C spin correlation in sucrose, confirming its high abundance in beetroot. Organic Extract: GC-MS data enabled the identification of several compounds including six fatty acid methyl esters (FAME) with higher than, on average, 90% similarity score. Selective TOCSY NMR data showed the spin coupling pattern corresponding to oleic, linoleic, and linolenic fatty acids. 31P NMR spectra indicate that phospholipids exist in both the organic and aqueous phase.

Effect of Maltodextrin, Arabic Gum, and Beetroot Juice Concentration on the Powder Properties of Spray-Dried Beetroot-Skim Milk Mixtures

Milk products are widely consumed as a beverage and used as the main ingredient in many food applications. Beetroot is suitable as an ingredient for the natural red color in food products. Color stability of natural colorants is mainly affected by mixtures of materials and temperatures. The effect of beetroot juice concentration and types of carrier agents on the physical properties of the red-colored skim-milk powder and rehydrated powder at different temperatures were studied. Beet juice concentration significantly affects the redness (a*) and lightness (L*) of skim milk in both powders and reconstituted forms. Powder with mixtures of maltodextrin and Arabic gum showed better retention of redness, high solubility, low moisture content, water activity, and less hygroscopic. The finding from this study may benefit food product development, beverage, and confectionery in the food industry.

Concentrations of Beetroot (Beta vulgaris L.) Peel and Flesh Extracts by Reverse Osmosis Membrane

The objective of this investigation was to concentrate betalains, phenolics, and antioxidants from the extract of peel and flesh of beetroot (Beta vulgaris L.). Thin-film composite reverse osmosis (RO) membrane composed of the thick polyamide barrier layer, microporous polysulfone interlayer, and polyester support web was used in membrane module. In a later exercise, thermo-instability of betalain color compounds was investigated with different temperatures. After the filtration of the aqueous extract of flesh, betacyanins, betaxanthins, and total betalains were increased by 5.2, 6.1, and 5.5 times, respectively. Likewise, the mentioned bioactive compounds were increased by 3.7, 4.9, and 4.2 times after filtration of the aqueous extract of peel. The amounts of total betalains measured in the final flesh extract were two times lower (14.33 ± 0.15 mg·g−1 dm) compared to the peel concentrate (30.02 ± 0.28 mg·g−1 dm). The superior amount of phenolic was shown in the final flesh extract (34.47 ± 0.19 mg GAE·g−1 dm) compared to peel extract (12.74 ± 0.42 mg GAE·g−1 dm). The antioxidant activity in final beetroot peel extract and flesh extract were 24.65 ± 1.42 mg ASE·g−1 dm and 11.6 ± 0.1 mg ASE·g−1 dm, respectively. The recovery of thermo-sensitive bio-colorants was achieved by membrane filtration with the least thermal degradation.

Mathematical Models to Describe the Foam Mat Drying Process of Cumbeba Pulp (Tacinga inamoena) and Product Quality

The present study investigated the mathematical modeling foam-mat drying kinetics of cumbeba pulp and the effect of drying conditions on the color and contents of ascorbic acid, flavonoids, and phenolic compounds of the powder pulps obtained. Foam-mat drying was carried out in a forced air circulation oven at temperatures of 50, 60, and 70 °C, testing foam-mat thicknesses of 0.5, 1.0, and 1.5 cm. The increase in the water removal rate is a result of the increase in air temperature and the decrease in the thickness of the foam layer. Among the empirical and semi-empirical mathematical models, the Midilli model was the one that best represented the drying curves in all conditions evaluated. Effective water diffusivity ranged from 1.037 × 10⁻⁹ to 6.103 × 10⁻⁹ m² s⁻¹, with activation energy of 25.212, 33.397, and 36.609 kJ mol⁻¹ for foam thicknesses of 0.5, 1.0, and 1.5 cm, respectively. Cumbeba powders showed light orangish colors and, as the drying temperature increased from 50 to 70 °C, for all thicknesses, the lightness value (L*) decreased and the values of redness (+a*) and yellowness (+b*) increased. Foam-mat drying at higher temperatures (60 and 70 °C) improved the retention of ascorbic acid and flavonoids, but reduced the content of phenolic compounds, while the increase in thickness, especially for flavonoids and phenolic compounds, caused reduction in their contents. The foam-mat drying method allowed obtaining a good-quality cumbeba pulp powder.

Effect of lacto-fermentation and freeze-drying on the quality of beetroot evaluated using machine vision and sensory analysis

This study was aimed at evaluating the effect of freeze-drying and lacto-fermentation on the texture parameters of images and sensory attributes of beetroots. The samples were imaged using a flatbed scanner, and textures from images converted to color channels L, a, b, R, G, B, X, Y, Z were computed. The discrimination of raw and processed beetroots was performed using models based on textures selected for each color channel. The sensory quality of processed samples was determined using the attributes related to smell, color, texture and taste. The highest discrimination accuracy of 97.25% was obtained for the model built for color channel b. The accuracies for other channels were equal to 96.25% for channel a, 95.25% for channel R, 95% for channel Y, 94.75% for channel B, 94.5% for channel X, 94% for channel L, 92.5% for channel G, 88.25% for channel Z. In the case of some models, the raw and lacto-fermented beetroots were discriminated with 100% correctness. The freeze-dried and freeze-dried lacto-fermented samples were also the most similar in terms of sensory attributes, such as off-odor, attractiveness color, beetroot color, crunchiness, hardness, bitter taste, overall quality. The results indicated that the image parameters and sensory attributes may be related.

Effect of processing on vitamin C content, total phenols and antioxidative activity of organically grown red beetroot ('Beta vulgaris' ssp. 'Rubra')

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 70 ºC and 90 ºC into beet juice or by drying at 55 ºC. 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 90 ºC. The lowest losses of studied phytochemical components were observed during juice pasteurisation at 70 ºC. The correlation coefficient between TPC and TAA was high and significant (r2 = 0.966).

Red Beetroot Betalains: Perspectives on Extraction, Processing, and Potential Health Benefits

In recent years, red beetroot has received a growing interest due to its abundant source of bioactive compounds, particularly betalains. Red beetroot betalains have great potential as a functional food ingredient employed in the food and medical industry due to their diverse health-promoting effects. Betalains from red beetroot are natural pigments, which mainly include either yellow-orange betaxanthins or red-violet betacyanins. However, betalains are quite sensitive toward heat, pH, light, and oxygen, which leads to the poor stability during processing and storage. Therefore, it is necessary to comprehend the impacts of the processing approaches on betalains. In this review, the effective extraction and processing methods of betalains from red beetroot were emphatically reviewed. Furthermore, a variety of recently reported bioactivities of beetroot betalains were also summarized. The present work can provide a comprehensive review on both conventional and innovative extraction techniques, processing methods, and the stability of betalains.

Three Types of Beetroot Products Enriched with Lactic Acid Bacteria

Beetroot (Beta vulgaris L.) represents a very rich source of bioactive compounds such as phenolic compounds and carotenoids, among which the most important being betalains, mainly betacyanins and betaxanthins. The beetroot matrix was used in a fresh or dried form or as lyophilized powder. A 10¹² CFU/g inoculum of Lactobacillus plantarum MIUG BL3 culture was sprayed on the vegetal tissue. The lactic acid bacteria (LAB) viability for all the products was evaluated over 21 days, by microbiological culture methods. The antioxidant activity of the obtained food products was correlated to the betalains content and the viability of LAB. The content of polyphenolic compounds varied between 225.7 and 1314.7 mg L⁻¹, hence revealing a high content of bioactive compounds. Through the confocal laser scanning microscopy analysis, a large number of viable probiotic cells were observed in all the variants but especially in the fresh red beet cubes. After 21 days of refrigeration, the high content of Lb. plantarum (CFU per gram) of the food products was attributed to the biocompounds and the nutrients of the vegetal matrix that somehow protected the bacterial cells, and thus maintained their viability. The obtained food products enriched with probiotic LAB can be regarded as new functional food products due to the beneficial properties they possessed throughout the undertaken experiments.

Development of several hybrid drying methods used to obtain red beetroot powder

Reduction of bioactive compounds sensitive to heat, light and oxygen could be attributed to drying. The effectiveness of microwave pretreatment at 525 or 420 W and the ohmic heating at 17.5 V/cm over the properties of beetroot powder were compared. This study aimed to develop novel hybrid drying methods. The effects of microwave and ohmic heating pre-treatment and subsequent microwave-convection drying were studied. Several investigations were performed, such as phenolic content, antioxidant activity, betalains content and color. The samples pretreated by microwave have registered higher polyphenols content and antioxidant capacity than those ohmically heated. The ohmic heating pretreated samples registered highest values for ΔL = 7.33-7.65 and ΔH = 8.18-10.02. Confocal microscopy reveals that the MW heating favors cellular lysis and cell content agglutinates. In conclusion, even if the MW preheating has certain disadvantages, in some cases it provides increased bioavailability generated by the vegetal cell disruption and the release of the bioactive compounds.

Mathematical modeling of uvaia byproduct drying and evaluation of quality parameters

Uvaia (Eugenia pyriformis) frozen pulp processing generates a solid byproduct that can potentially contain important components of human nutrition. In this study, the drying of uvaia byproduct was studied. Two different drying treatments were tested: drying of wet waste and drying of waste with prior removal of water by centrifugation. Three drying temperatures were used: 40, 60, and 80 °C. Eight models were applied to fit the drying curves: Page, Lewis, Modified Page, Logarithmic, Midilli, Wang and Singh, Henderson and Pabis, and Weibull. Midilli presented an excellent fit to the curves. The effective moisture diffusivity of the uvaia byproduct ranged between 8.52 × 10^-10 and 3.22 × 10^-9 m²/s. The activation energy was 25.65 and 24.97 kJ/mol for non-centrifuged and centrifuged assays, respectively. The dried byproducts had a reduction of 3-21% of the total phenolic content against the control. The assay performed at 40 °C with centrifugation presented the lowest total color difference value.

Minimally processed beetroot waste as an alternative source to obtain functional ingredients

Large amounts of waste are generated by the minimally processed vegetables industry, such as those from beetroot processing. The aim of this study was to determine the best method to obtain flour from minimally processed beetroot waste dried at different temperatures, besides producing a colorant from such waste and assessing its stability along 45 days. Beetroot waste dried at 70 °C originates flour with significant antioxidant activity and higher betalain content than flour produced from waste dried at 60 and 80 °C, while chlorination had no impact on the process since microbiological results were consistent for its application. The colorant obtained from beetroot waste showed color stability for 20 days and potential antioxidant activity over the analysis period, thus it can be used as a functional additive to improve nutritional characteristics and appearance of food products. These results are promising since minimally processed beetroot waste can be used as an alternative source of natural and functional ingredients with high antioxidant activity and betalain content.

Influence of different drying methods on the physicochemical properties of red beetroot (Beta vulgaris L. var. Cylindra)

There is an increased interest in preserving fruits and vegetables by drying. The novelty of this study consists in the combination of the following three drying methods: free convection (at 50, 60, and 70°C), forced convection at 40°C and 315W microwave power. The aim of this study was to investigate the effects of the drying conditions on red beetroot (Beta vulgaris L.) in terms of betalain variance, and polyphenol, microstructure changes (SEM). A strong thermal shock, provided by convection at 60° followed by microwave wattage 315W/9min, leads to a better preservation of bioactive compounds content (0.631±0.0042mg/g of betacyanin and 0.795±0.0019mg/g betaxanthin) when compared to convection at 50, 60 and 70°C. The results showed that combined drying methods led to a significant preservation of the phytochemical content as compared to the traditional methods.

Optimization and quality assessment of ready-to-eat intermediate moisture compressed beetroot bar

A ready-to-eat food product in the form of compressed bar from beetroot, enriched with dates and oats was developed. Levels of intermediate moisture beetroot shreds (60-100 g), dates (10-30 g) and oats (5-15 g) were optimized using response surface methodology and its quality attributes were investigated over a period of 6 months at different temperature conditions (ambient temperature; 22-32 and 37 °C). Optimum formulation for best beetroot bar consisted of beetroot shreds, dates and oat were derived as 71.8, 21.2, and 8.4 g, respectively. Developed product was found rich in fibers and minerals and recorded 38.4 mg/100 g betacyanains, 23.1 mg/100 g betaxanthins, 295 mg/100 g total phenolics (TP) and 160 mg/100 g total flavonoids (TF). The shelf stability studies of bar revealed predominant changes in bioactive compounds was caused by storage temperature. A loss of around 30, 15, 25, 31 and 32 % was observed for betacyanins, betaxanthins, TP, TF and radical scavenging activity, respectively during storage of 6 months at 6 °C compared to AT or 37 °C temperature conditions. The product had high overall sensory acceptability as well as microbial safety up to 6 months when stored at AT. The study indicated that beetroot could be effectively utilized into a novel shelf-stable ready-to-eat nutritious compressed product.

Home-Processed Red Beetroot (Beta vulgaris L.) Products: Changes in Antioxidant Properties and Bioaccessibility

In this study, the effects of home-processing on the antioxidant properties and in vitro bioaccessibility of red beetroot bioactives were investigated. For this purpose, fresh red beetroot and six different home-processed red beetroot products-including boiled, oven-dried, pickled, pureed, juice-processed, and jam-processed-were analyzed and compared for their total phenolic (TP) and total flavonoid (TF) contents, total antioxidant capacities (TAC), and individual anthocyanin contents. In addition, bioaccessibility of red beetroot antioxidants was determined using an in vitro simulated gastrointestinal digestion method. Dried, pureed, and fresh red beetroot samples had the highest TP, TF, and TAC values, which were 347 ± 23 mg gallic acid equivalent (GAE)/100 g, 289 ± 53 mg rutin equivalent (RE)/100 g, 3889 ± 982 mg trolox equivalent antioxidant capacity (TEAC)/100 g, respectively. The in vitro digestion method revealed the highest recovery for TP (16%) and TAC (1.3%) in jam. This study provides comparative data to evaluate the effects of various home-processing techniques on antioxidant potential of red beetroot products.

Drying of red beetroot after osmotic pretreatment: Kinetics and quality considerations

This article presents experimental studies on drying kinetics and quality effects of red beetroot (Beta vulgaris L.) after convective drying with a preliminary osmotic pretreatment. The effects of the osmotic agent (NaCl) concentration and the osmotic bath time on the product colour and nutrient content preservation, the water activity, and rehydration ability after drying were analysed. Osmotic dehydration curves and Solid Gain (SG), Water Loss (WL), Weight Reduction (WR) were determined. It was proved that drying of beetroot with osmotic pretreatment contributes to shorter drying time, smaller water activity, higher retention of betanin, better colour preservation, and a greater degree of water resorption.

Degradation of colour in beetroot (Beta vulgaris L.): a kinetics study

The kinetics of colour (measured as Hunter 'a/b' value) degradation in beetroot puree (Beta vulgaris L.) was studied over a temperature range of 50-120 °C (isothermal process), and also during normal open pan cooking, pressure-cooking and a newly developed and patented fuel-efficient 'EcoCooker' (non-isothermal heating process). The degradation of visual colour as measured as Hunter 'a/b' value was found to follow a first order kinetics, where the rate constant increased with an increase in the temperature. The temperature dependence of degradation was adequately modeled by Arrhenius equation. A mathematical model has been developed using the kinetic parameters obtained from the isothermal experiments to predict the losses of color in the non-isothermal heating/processing method based on the time-temperature data for each of the methods. The results obtained indicate a colour degradation of similar magnitude in all the three modes of cooking used in the study.