Investigations on beetroot colours for the purpose of regulation

Summary Six commercially available colour products were fractionated on Sephadex, Bio-Gel- and Polyclar, colums, and the celow content of individual fractions determined by spectrophotometric measurements. Betanine was found to comprise 75%–95% of the red pigments. As betanine and closely related compounds were found to form the main part of the red colour of beetroot colour preparations, it was concluded that the red colour content of these products might be determined spectrophotometrically without prior separation. A formula for calculating the red colour content is given and, in the Danish national specification for beetroot food colours, the colour strength is based on this formula.The colour products were also examined by electrophoresis and TLC, and tests for identity were investigated. An attempt was made to obtain crystalline betanine but without success.

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Untersuchungen über die Farbstoffe der roten Beete zum Zwecke der Regulierung

Zusammenfassung Sechs kommerziell erhältliche Farbstoffe wurden in Sephadex-, Biogel- und Polyclarsdulen fraktioniert, und der Farbstoffgehalt der einzelnen Fraktionsprodukte mittels spektrophotometrischer Messungen bestimmt. Der Betaningehalt wurde zu 75–95% bestimmt. Da Betanin und eng verwandte Verbindungen den größten Teil des Farbstoffes von Auszügen der roten Beete bilden, ergibt sich, daß der Gehalt an rotem Farbstoff auf spektrophotometrischem Wege ohne vorherige Trennung bestimmt werden kann. Eine Formel zur Berechnung des Gehaltes an rotem Farbstoff von Auszügen roter Beete wird angegeben, und in der nationalen dänischen Vorschrift über den LebensmittelfarbstoffBeetenrot wird diese Formel zur Bestimmung des Gehalts an rotem Farbstoff angewendet.Die Farbstoffe wurden mittels Elektrophorese und Dünnschichtchromatographie untersucht und Identitätstests ausgeführt. Ein Versuch, kristallines Betanin herzustellen, wurde durchgeführt, aber ohne Erfolg.

     

Butternut and beetroot pectins: Characterization and functional properties

The physicochemical characteristics and functional properties of butternut (Cucumis moschata Duch. ex Poiret) and beetroot (Beta vulgaris L. var. conditiva) pectins obtained by enzymatic extraction from by-products of vegetable processing have been evaluated. The molecular mass distribution was determined using Gel Permeation Chromatography using light scattering, refractive index and UV detectors and the samples were found to be highly heterogeneous and polydisperse. M_w values of 136,000 and 1,309,000 g/mol were determined for butternut and beetroot pectins respectively. Butternut pectin had a high degree of methyl esterification. In the presence of high concentrations of sugar and at low pH, this pectin did not form gels but instead produced viscous solutions. Solutions showed pseudoplastic flow behaviour with a shear thinning index of 0.68 as determined from the Power law model. Beetroot pectin had a low degree of methyl esterification and formed gels with addition of Ca²⁺ at concentrations of 10 mg/g pectin or higher. The maximum value of the storage modulus was obtained at a Ca²⁺/GalA ratio of 0.25. The thermal stability of gels suggested that hydrogen bond interactions prevailed in the absence of Ca²⁺, whereas electrostatic junction zones increasingly developed between pectin chains as the calcium concentration increased. Aqueous solutions of butternut and beetroot pectins significantly reduced surface tension and both samples were able to form stable oil-in-water emulsions. It was found that protein and/or polyphenol – rich fractions present in the pectins adsorbed at the oil–water interface and were responsible for the emulsification properties.     

Degradation kinetics of beetroot pigment encapsulated in polymeric matrices

Kinetic studies on the degradation of water‐soluble beetroot pigment, mainly consisting of the betalain betanin, encapsulated in three different matrices (pullulan and two maltodextrin samples differing in their molecular weight) were carried out under various water activity (a_w = 0.23, 0.43, 0.64, 0.75 and 0.84) and temperature (30, 40 and 50 °C) conditions. The water sorption behaviour of these materials was also examined. Degradation of the pigment was monitored by absorbance measurements at 537 nm (λ_max of betanin). The highest values of the rate constants for degradation were observed at an intermediate water activity level (a_w = 0.64) for all matrices and all three storage temperatures examined. An attempt to relate the degradation kinetics to the molecular mobility of the wall material was not successful. Pigment losses were observed even at temperatures below the glass transition temperature (T_g) of the polymeric matrices, although degradation was largely slowed down in the glassy state. In the vicinity of the T_g zone, where all polymers go through a glass → rubber transition, there was not a distinct change in the reaction rate, which could reflect the pronounced changes in molecular mobility of the wall material. In fact, some of the lower degradation rates were observed mostly under conditions where the matrices were fully plasticised (ie rubbery) and ‘collapsed’, implying that the degradation kinetics is not governed by factors related only to the physical state of the polymeric wall material. © 2001 Society of Chemical Industry     

Characterization of the phenolic acid profile and in vitro bioactive properties of white beetroot products

The impact of boiling, baking and fermentation treatment on the phenolic acid profile, antioxidant capacity (AC) and angiotensin-1 converting enzyme (ACE) activity of white beetroot was investigated. The phenolic acids were analysed by liquid chromatography–mass spectrometry (micro-HPLC-MS/MS), while AC and ACE were determined by in vitro assays. Phenolic acids concentration was between 87.55 and 100.98 ng g⁻¹ d.m. Ferulic and p-coumaric acids were the main compounds among the nine phenolic acids identified. Boiling increased the phenolic acid content by 3%; however, baking and fermentation reduced the level of these acids by approximately 6% and 11%, respectively. A significant positive correlation was observed between the results of all AC assays and sinapic and caffeic acid content. The ACE inhibitory activity of white beetroot products may be attributable to the combined effect of the syringic, 4-hydroxybenzoic, ferulic and p-coumaric acids. Our study indicates that white beetroot as a novel product may be a valuable source of phenolic acids and functional properties.     

Betalain and phenolic compositions of four beetroot (Beta vulgaris) cultivars

Four cultivars of red beetroot (Beta vulgaris) were evaluated with respect to their betalain and phenolic contents. The compounds were analysed using HPLC and identified by HPLC-DAD, HPLC-ESI-MS and NMR techniques. Betalains (vulgaxanthins I and II, betanin and isobetanin) and phenolics [5,5',6,6'-tetrahydroxy-3,3'-biindolyl, feruloylglucose and #-D-fructofuranosyl-!-D-(6-O-(E)-feruloylglucopyranoside)] were determined in different parts of the root; betalains were analysed separately in the water extract and phenolics in the fractionated 80% aqueous methanol extract (betalain-free water fraction). In each cultivar, both betanin and isobetanin were found in greater amounts in the peel than in the flesh. A similar trend was not observed in the distribution of vulgaxanthins. The three studied phenolics appeared in all root parts of the beetroot cultivars with the flesh generally containing the least content. Additionally, two phenolic amides (N-trans-feruloyltyramine and N-trans-feruloylhomovanillylamine) and four flavonoids (betagarin, betavulgarin, cochliophilin A and dihydroisorhamnetin) were detected in the fractionated 80% aqueous methanol peel extracts (acetonitrile fraction) of beetroot.     

Comparison of total antioxidant potential,and total phenolic,nitrate, sugar,and organic acid contents in beetroot juice,chips, powder,and cooked beetroot

Beetroot is a vegetable rich in nitrate (NO ₃ ^? ), antioxidants and phenolic compounds that are related to improvements in cardiovascular function and exercise performance. However, it is unknown if convenient forms of beetroot administration provide different amounts of these nutrients. The total antioxidant potential (TAP), total phenolic (TPC), sugar, organic acid, and NO ₃ ^? contents of beetroot juice (BJ), chips (BC), powder (BP), and cooked beetroot (CB) were compared. Significant (p<0.01) differences in chemical compositions and functional properties were found between beetroot formulations. Higher amounts of TAP and organic acids were observed in BC and BP, compared with the other formulations. BJ exhibited the highest contents of total sugars, TPC, and NO ₃ ^? . All beetroot formulations were suitable and advantageous based on taste preferences and convenience for consumers and for nutrient amounts required to meet dietary recommendations.     

Development of functional pectin edible films with fillers obtained from red cabbage and beetroot

The present study aims to develop through casting, functional composite edible films based on pectin using beetroot powder and red cabbage powder as fillers obtained from by-products of plant tissue industrialisation. Physico-chemical, mechanical, thermal properties and colour stability of the films along 30 days of storage (5–45 °C; absence of light) were evaluated. The moisture and the stress at break decreased, and the intensity of red colour and the hydrophobicity increased with the presence of fillers. According to the FTIR results, there was a good compatibility between matrix and fillers in the composites. Pectin films generated an enhanced stability of red colour after 30 days of storage at 5 and 25 °C and, in general, after 16 days for 45 °C, showing their suitability to be used as colouring agents for edible food packaging applications.     

A beetroot juice shot is a significant and convenient source of bioaccessible antioxidants

The total antioxidant capacity (TAC) and total polyphenol (TP) content of a beetroot juice shot (70 mL) was examined following in vitro digestion. TAC was assessed using the ferric reducing antioxidant power (FRAP) assay and TP content was measured using the Folin Ciocalteu (FC) method (measured as gallic acid equivalents (GAE) before and after an in vitro digestion procedure with simulated gastric (GAS) and duodenal (DUO) phases. The beetroot shot had a high TAC (697.9 ± 1.6 μmol/70 mL) and TP content (68.4 ± 0.3 mg GAE/70 mL). FRAP values increased approximately 3-fold after GAS (2361.2 ± 20.9 μmol/70 mL) and remained high following DUO (1740.3 ± 21.1 μmol/70 mL). TP content increased 5-fold following GAS (341.6 ± 4.8 mg GAE/70 mL) and remained 3.3-fold higher following DUO (223.2 ± 5.4 mg GAE/70 mL). The beetroot shot delivers a high amount of bioaccessible antioxidants and may be a cost effective and convenient method of increasing antioxidant status.     

The effect of electrical processing on mass transfer in beetroot and model gels

The diffusion between solids and surrounding liquids has been studied under the influence of different electric field strengths varying between 0–1000 V m⁻¹, characteristic both of ohmic heating and Moderate Electric Field (MEF) processing. The rate of enhancement of mass transfer between slabs of beetroot and surrounding fluid has been studied at up to 60 °C, as a function of electric field strength and the orientation of the slab to the field. Enhancements in diffusion coefficient of up to a factor of 2 are seen, with decreased enhancement at higher temperature and when the electric field does not pass through the particle. Diffusion into gels has been studied and enhancement found only for alginate (an ionically set gel) and not for gelatin and egg albumin, that are thermally set gels.     

短期摄入甜菜根汁对足球运动员体能和认知能力影响

目的 评估连续3天摄入甜菜根汁(BRJ)对足球运动员爆发力、反复冲刺能力和疲劳状况下认知水平的影响。方法 本研究招募24名男性大学生足球运动员,采用随机、双盲、安慰剂对照实验设计,分为对照组、低剂量组[每天分2次共摄入300 mL(0.53%NO₃^-)BRJ]、高剂量组[每天分2次共摄入300 mL(4%NO₃^-),BRJ],受试者首先进行前测[反向跳跃(CMJ)、有Yo-Yo间歇恢复测试(YY1R)、stroop色词测试]建立基线,进行3天不同NO₃^-浓度BRJ或安慰剂补充,期间保持正常训练生活。最后1次补充BRJ后2 h后进行检测。结果 经过短期BRJ补充,YY1R方面,低剂量组和高剂量组相较于对照组,跑动距离指标显著增加(P<0.05),且高剂量组的跑动距离明显多于低剂量组(P<0.05)。测试过程中,第1～12趟冲刺的RPE,各组间没有显著性差异(P>0.05);第13～20趟冲刺对照组RPE值显著高于低剂量和高剂量组(P<...     

Effects of processing conditions on soluble sugars content of carrot,beetroot and turnip

The effect of processing conditions on the soluble sugars fraction of three vegetables, carrot, beetroot and turnip, was evaluated by high-performance liquid chromatography (HPLC) and by a colorimetric method using potassium ferricyanide. Processing was performed at 121°C during 15 min and three different lots of each vegetable were studied. To verify whether the behaviour was homogeneous, each lot was processed three times, consecutively, under the same conditions. Results were statistically evaluated by two-way ANOVA to elucidate the effects of processing on each vegetable. A significant reduction was observed of soluble sugars, fructose, glucose and sucrose, in the processed samples. A high correlation was observed between the results of total sugars obtained by HPLC and by the colorimetric method.     

Effect of lactobacillus fermented beetroot juice on composition and activity of cecal microflora of rats

This study aimed at determination of the effect caused by ingestion of beetroot juice fermented by Lactobacillus casei 0920 and Lactobacillus brevis 0944 strains on the state of cecal ecosystem of experimental rats. The intake of fermented beetroot juice containing 3.5–4.0 × 10⁹ CFU/mL live Lactobacillus sp. cells positively modulated the cecal microflora of the rats and its metabolic activity. The counts of Lactobacillus sp., Bifidobacterium sp., Bacteriodes sp., and Enterococcus sp. were maintained at the level of 8.2–8.6, 6.2–7.5, 8.0–8.3, and 7.3–7.7 log units, respectively, while the number of Clostridium sp. cells was increased by 1.1–1.6 log units and Enterobacteriaceae bacteria were reduced by 0.8–2.1 log units. In this study, the selected cecal enzymes such as β-glucosidase, β-glucuronidase, and β-galactosidase as well as the profile and concentration of short chain fatty acids (SCFA) were the biochemical markers of metabolic activity of the intestinal ecosystem. The considerable decrease in activities of β-glucosidase and β-glucuronidase was observed in all three experimental groups fed with the fermented beetroot juice. Total concentration of SCFA was the highest (78.1 μmol/100 g BW vs. 59.2 μmol/100 g BW in control group) in intestines of rats fed with 6 mL of fermented beetroot juice daily. These results prove that the fermented beetroot juice benefits cecal microbial activity.     

Microwave-assisted infrared dry-peeling of beetroot: Peeling performance,product quality,and cell integrity

The use of low power-short time microwave (MW) treatment before infrared (IR) heating could help improve the peeling performance of beetroot. MW-assisted IR peeling (MWIR) and IR peeling of beetroot were investigated and compared with the conventional hot-lye peeling method. Also, the effects of these peeling methods on the quality and microstructure were evaluated. Hot-lye peeling at 95 °C for 40 s and 60 s was used as control. Results showed that MW-assisted IR peeling at power 640 W and heating time 7 min produced samples with the highest peelability (99.4%), lowest peel thickness (0.075 mm), and peel remaining (0.8%), lower peeling loss (4.23 g), and better peeling easiness when compared with lye peeling and IR peeling. IR peeling alone produced samples with the lowest peeling loss (2.87 g) and surface colour change, and the highest vitamin C retention (75.32%) than MW-assisted IR and lye peeling respectively. The product microstructure for the different peeling methods showed cellular distortion as a result of thermal expansion. MW pretreatment shows a promising potential to further develop the IR dry-peeling method, to replace the conventional hot lye chemical peeling.     

Survival of Lactobacillus casei and functional characteristics of reduced sugar red beetroot yoghurt with natural sugar substitutes

In this study, probiotic gel fermentation and functional characteristics of reduced sugar yoghurt with red beetroot bioactive components and steviol glycosides from Stevia rebaudiana extracts as natural source of noncaloric sweeteners were investigated. A significant increase in Lactobacillus casei viability and fermented gel network and a decrease in syneresis were determined in yoghurt sweetened with steviol glycosides and high content of red beetroot bioactive components such as total phenolics, anthocyanins and total antioxidant capacity (DPPH and FRAP). The survival of L. casei was maintained within probiotic and therapeutic levels (>9 log₁₀ CFU/g), due to the possible prebiotic effect of steviol glycosides and fermentable fibres and phenolic compounds of red beetroot during 28 days of cold storage of the probiotic yoghurts. Colour properties (L*, a*, b*, ΔE*, C*, h*) and such sensory properties as smoothness, sweetness astringency were significantly affected. The highest organic acid content was found in red beetroot enriched yoghurt with stevia, while the most dominant organic acids were butyric, lactic, malic and citric. As a result, it was determined that fermented milk products, which are supported by phytochemical and steviol glycoside interactions, have adequate nutritional effects, high probiotic viability and acceptable sensory properties     

The influence of Lactobacillus bacteria type and kind of carrier on the properties of spray-dried microencapsules of fermented beetroot powders

The aim of this study was to evaluate the influence of bacteria type and carrier addition during microencapsulation process by spray-drying on the microorganism survival and physicochemical properties of fermented beetroot juice powder. Selected bacteria were as follows: L. fermentum, L. plantarum and L. brevis and its mixture in proportion 1:1:1. Fermented beetroot juice containing selected LAB was spray-dried at 160 °C. Maltodextrin and gum Arabic were used as drying carriers at 10% (w/w). All powders were stable (low water activity below <0.25, high dry matter content 95–98%). Bacteria type had the main influence on the chemical properties and amount of bacteria. The highest bacteria content was observed in powders with L. brevis as a starter, and the same was observed for polyphenols and betalain content. However, the method of drying fermented juices still needs to be refined due to the 50% reduction in the number of microorganisms during the drying process.