Process optimization of spray drying of beetroot Juice

The aim of this study was to optimize the spray drying process for beetroot juice. Influence of feed flow rate (8, 10 and 11 mL/min), processing temperature (140, 150 and 160 °C) and maltodextrin concentration (20, 25, and 30%) on packed bulk density, moisture content and betalain content of beetroot powder were assessed using response surface methodology. The following optimum process parameters were determined; feed flow rate feed flow rate of 10 mL/min, processing temperature of 149 °C and maltodextrin concentration of 20%. The predicted values for packed bulk density, moisture content and betalain content were 0.62 g/mL, 6.12 and 33.84 mg/100 g of dry matter, respectively. Within the optimum parameters, the experimental values for packed bulk density, moisture content and betalain content were 0.62 ± 0.1 g/mL, 6.10 ± 0.1 and 33.14 ± 0.1 mg/100 gm of dry matter. The similarity of the experimental results to the predicted values verified the models.

Partial purification and characterization of amylase enzyme under solid state fermentation from Monascus sanguineus

Amylase is an important enzyme having a varied range of industrial applications from food to cosmetics, from pharmaceutical to detergent industry, etc. The present study was carried out considering these important applications of amylase enzyme. Monascus sanguineus also has not been explored for its efficiency to produce amylase enzymes under solid state fermentation. In the present study, various substrates were screened and among them beetroot as a solid substrate has given maximum yield (0.029 U/mL). Enzyme activity was further optimized by response surface methodology (RSM) and maximum experimental yield of 0.014 U/mL was obtained at optimized conditions of pH 5, incubation temperature of 50 °C and 10 min incubation time. A MATLAB software package was used for the graphical and regression analysis of the experimented data. Enzyme kinetics was calculated with different concentrations of starch and observed Km value was 0.055 mM from linear regression analysis. The enzyme was moderately inhibited (44.7%) by NaCl and KCl (0.105 U/mL) with minimum inhibition (14.8%) observed with SDS. Molecular weight calculation and amylase confirmation in protein sample was done by SDS-PAGE and Zymography. Calculated molecular weight was 56 kDa. Alkaline amylase produced by M. sanguineus has exhibited high efficiency towards removal of stains on cloths in combination with commercial detergent (Surf excel) at 20 °C. It can be concluded that the fungus M. sanguineus is a good source of amylase production under solid state fermentation. Application of amylase produced by M. sanguineus in detergent industry was also carried out and it was proven very effective in stain removal from the fabrics.

The effect of six days of dietary nitrate supplementation on performance in trained CrossFit athletes

BACKGROUND

While it is well established that dietary nitrate reduces the metabolic cost of exercise, recent evidence suggests this effect is maintained 24 h following the final nitrate dose when plasma nitrite levels have returned to baseline. In addition, acute dietary nitrate was recently reported to enhance peak power production. Our purpose was to examine whether chronic dietary nitrate supplementation enhanced peak power 24 h following the final dose and if this impacted performance in a heavily power-dependent sport.

METHODS

In a double-blind, randomized, crossover design, maximal aerobic capacity, body composition, strength, maximal power (30 s Wingate), endurance (2 km rowing time trial), and CrossFit performance (Grace protocol) were assessed before and after six days of supplementation with nitrate (NO) (8 mmol·potassium nitrate·d^-1) or a non-caloric placebo (PL). A 10-day washout period divided treatment conditions. Paired t-tests were utilized to assess changes over time and to compare changes between treatments.

RESULTS

Peak Wingate power increased significantly over time with NO (889.17 ± 179.69 W to 948.08 ± 186.80 W; p = 0.01) but not PL (898.08 ± 183.24 W to 905.00 ± 157.23 W; p = 0.75). However, CrossFit performance was unchanged, and there were no changes in any other performance parameters.

CONCLUSION

Consuming dietary nitrate in the potassium nitrate salt form improved peak power during a Wingate test, but did not improve elements of strength or endurance in male CrossFit athletes.

Emerging technique for healthier frying for production of reduced-fat beetroot (Beta vulgaris) chips

In the present work, the processing variables were optimized to retain betalain compound and their effect on quality attributes (oil content, breaking force and color) of fried beetroot chips. The beetroot slices were fried in lab scale vacuum fryer. Experimental design with temperature (86-153 °C), absolute pressure (1.3-9.7 kPa) and frying time (2.6-9.4 min) as independent variables which produced 20 different combinations, were studied using response surface methodology to study the effect of these variables on product responses. Multiple regression equations were obtained to describe the effects of each variable on product responses. Results predicted that optimum frying conditions namely temperature ranging from 101 to 110 °C, pressure ranging from 2.9 to 4.4 kPa and time 6.0 min required for preparing beetroot chips with oil content (Y₁) ≤ 15.7, breaking force (Y₂) ≤ 11.53, L* value (Y₃) ≥ 27.94, a* value (Y₄) ≤ 17.87, b* value (Y₅) ≥ 6.46, betalain content (Y₆) ≥ 13.05 (mg/l) and overall acceptability (Y₇) ≥ 7.5. Further results showed that traditionally fried beetroot chips contain 2.6 mg/l betalain, 19.68 N breaking force, 21.1 L*, 15.18 a*, 2.38 b*, overall acceptability 6.0 and 38.41 % oil content.

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.

Degradation kinetics of bioactive components, antioxidant activity, colour and textural properties of selected vegetables during blanching

Bioactive components of fruit and vegetables play an important role in scavenging free radicals and protect the body from degenerative diseases. A kinetic study was conducted to quantify the losses occurring in bioactive components, antioxidant activity and changes in colour and firmness of four commonly used vegetables (beetroot, green pea, eggplant and green pepper) during heat treatment (70-90 °C). The study revealed that logistic model can predict the variation in bioactive components and antioxidant activity with higher R² and lower root mean square error (RMSE) as compared to first order model due to logarithmic reduction in these properties in the beginning of the process itself. However zero and first order kinetic models were found suitable to predict the changes occurring in colour and firmness respectively during blanching. D, z value, activation energy (E_a), activation enthalpy and entropy were calculated for all measured parameters for selected vegetables in the temperature range of 70-90 °C. These finding would be useful in designing thermal processes and related calculations for these vegetables.

The plasma bioavailability of nitrate and betanin from Beta vulgaris rubra in humans

Purpose

To evaluate the plasma bioavailability of betanin and nitric oxide (NOx) after consuming beetroot juice (BTJ) and whole beetroot (BF). BTJ and BF were also analysed for antioxidant capacity, polyphenol content (TPC) and betalain content.

Methods

Ten healthy males consumed either 250 ml of BTJ, 300 g of BF or a placebo drink, in a randomised, crossover design. Venous plasma samples were collected pre (baseline), 1, 2, 3, 5 and 8 h post-ingestion. Betanin content in BTJ, BF and plasma was analysed with reverse-phase high-performance liquid chromatography (HPLC) and mass spectrometry detection (LCMS). Antioxidant capacity was estimated using the Trolox equivalent antioxidant capacity (TEAC) and polyphenol content using Folin–Ciocalteu colorimetric methods [gallic acid equivalents (GAE)] and betalain content spectrophotometrically.

Results

TEAC was 11.4 ± 0.2 mmol/L for BTJ and 3.4 ± 0.4 μmol/g for BF. Both BTJ and BF contained a number of polyphenols (1606.9 ± 151 mg/GAE/L and 1.67 ± 0.1 mg/GAE/g, respectively), betacyanins (68.2 ± 0.4 mg/betanin equivalents/L and 19.6 ± 0.6 mg/betanin equivalents/100 g, respectively) and betaxanthins (41.7 ± 0.7 mg/indicaxanthin equivalents/L and 7.5 ± 0.2 mg/indicaxanthin equivalents/100 g, respectively). Despite high betanin contents in both BTJ (~194 mg) and BF (~66 mg), betanin could not be detected in the plasma at any time point post-ingestion. Plasma NOx was elevated above baseline for 8 h after consuming BTJ and 5 h after BF (P < 0.05).

Conclusions

These data reveal that BTJ and BF are rich in phytonutrients and may provide a useful means of increasing plasma NOx bioavailability. However, betanin, the major betalain in beetroot, showed poor bioavailability in plasma.

Dietary nitrate modulates cerebral blood flow parameters and cognitive performance in humans: A double-blind, placebo-controlled, crossover investigation

Nitrate derived from vegetables is consumed as part of a normal diet and is reduced endogenously via nitrite to nitric oxide. It has been shown to improve endothelial function, reduce blood pressure and the oxygen cost of sub-maximal exercise, and increase regional perfusion in the brain. The current study assessed the effects of dietary nitrate on cognitive performance and prefrontal cortex cerebral blood-flow (CBF) parameters in healthy adults. In this randomised, double-blind, placebo-controlled, parallel-groups study, 40 healthy adults received either placebo or 450 ml beetroot juice (~5.5 mmol nitrate). Following a 90 minute drink/absorption period, participants performed a selection of cognitive tasks that activate the frontal cortex for 54 min. Near-Infrared Spectroscopy (NIRS) was used to monitor CBF and hemodynamics, as indexed by concentration changes in oxygenated and deoxygenated-haemoglobin, in the frontal cortex throughout. The bioconversion of nitrate to nitrite was confirmed in plasma by ozone-based chemi-luminescence. Dietary nitrate modulated the hemodynamic response to task performance, with an initial increase in CBF at the start of the task period, followed by consistent reductions during the least demanding of the three tasks utilised. Cognitive performance was improved on the serial 3s subtraction task. These results show that single doses of dietary nitrate can modulate the CBF response to task performance and potentially improve cognitive performance, and suggest one possible mechanism by which vegetable consumption may have beneficial effects on brain function.

Free radical scavenging and antioxidant activity of betanin: electron spin resonance spectroscopy studies and studies in cultured cells

Betanin is a red pigment present in red beetroot. Recently, potential health benefits of betanin-rich beetroot have been suggested. However, little is known regarding the free radical scavenging and antioxidant activity of betanin. Electron spin resonance spectroscopy (ESR) and spin trapping techniques were applied to evaluate the ability of betanin to scavenge hydroxyl, superoxide, 2,2 diphenyl-1-picrylhydrazyl (DPPH), and galvinoxyl free radicals. In addition, we tested in cultured cells the ability of betanin to prevent DNA damage and to induce the transcription factor Nrf2 (nuclear factor (erythroid-derived 2)-like 2) as well as its down-stream target heme oxygenase1 (HO-1), paraoxonase1 (PON1) and glutathione (GSH). Betanin dose-dependently scavenged DPPH-, galvinoxyl-, superoxide-, and hydroxyl-radicals in the ESR and spin trapping studies and prevented hydrogen peroxide induced DNA damage as determined by the Comet assay. Furthermore, betanin treatment induced the transcription factor Nrf2 and resulted in an increase of HO-1 protein levels, PON1-transactivation and cellular GSH. Present data suggest that betanin is both a free radical scavenger and an inducer of antioxidant defense mechanism in cultured cells.

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.