Physicochemical, antioxidant and sensory evaluation of a beetroot juice-based functional energy drink

Introduction

The innovation and advancement over the past several years has facilitated a plethora of functional beverages. A functional beverage can be defined as "any non-alcoholic drink that provides additional health benefits due to the inclusion of any bioactive component from a plant, animal, marine or microorganism source" (Gayathry & John, 2021) [5] . Functional beverages can be classified as dairy-based beverages (including probiotics and mineral enriched drinks), vegetable and fruit beverages, sports and energy drinks (Corbo et al. 2014) [4] . Functional beverages are gaining popularity due to increasing consumer awareness regarding health promoting foods rich in bioactive compounds. Beetroot is recognized as an excellent source of betalains, phenolic compounds, flavonoids, minerals and dietary fibre (Chhikara et al. 2019) [3] . Beetroot juice contains biologically accessible antioxidants and inorganic nitrates which have been associated with improved cardiovascular health, enhanced exercise performance and reduced oxidative stress (Wootton et al. 2011) [15] . Litchi and pear juices contribute desirable flavour and additional nutrients, whereas ashwagandha is traditionally known for its adaptogenic and energy enhancing properties. Development of a beetroot based energy drink incorporating these ingredients provides an opportunity to formulate a novel functional beverage with improved nutritional quality and consumer acceptability.

Material and Methods

Procurement of beetroot

Fresh and optimally mature beetroot, ashwagandha, litchi and pear were purchased from the local market of Palampur, Himachal Pradesh, ensuring they were free from any bruises or damage.

Development of beetroot juice

Beetroots were kept in freezer for one day for (Freezing process of fresh beetroots could have led to higher degree of tissue damage resulted in an increased extraction of betalains reported by Bianchi et al. 2021). After peeling it was cut in pieces and crushed in mixer grinder to extract juice.

Sensory evaluation of developed energy drink

A group of 10 sanctioned judges from the Department of Food Science, Nutrition, and Technology at COCS, CSKHPKV, Palampur conducted sensory evaluation of different functional beverages made with beetroot as the main ingredient. Each judge received one control sample and four other treatments E1, E2, E3, E4 for energy drink. The control treatment followed a standard recipe, while the other four treatments involved blending of functional ingredients such as litchi juice, pear juice and ashwagandha in varying proportions with the standard recipe. To ensure impartial evaluation, the samples were given numerical codes.

Panellists were instructed to rate the products based on various attributes like colour, appearance, consistency, flavour, taste, and overall acceptability using a scorecard that used a nine-point hedonic scale, following the guidelines described in Larmand, 1977.

Nutritional analysis: Moisture, crude fat, crude protein, crude fibre, ash content, and total carbohydrate contents were determined according to the standard procedures of AOAC (2010) [1] for proximate composition analysis. Total soluble solids (TSS) and titratable acidity were estimated following the methods described by Rangana (2014). Ascorbic acid content was determined using the method of Rangana (2007). Total sugars and reducing sugars were estimated by the Lane and Eynon (1923) method as reported by Rangana (2014) [16,17,18] , while non-reducing sugars were calculated from the difference between total sugars and reducing sugars. Total phenolic content and total flavonoid content were determined according to the methods of Singleton et al. (1999) and Zhishen et al. (1999) [11,14] , respectively. Antioxidant activity was evaluated using the DPPH radical scavenging assay described by Brand-Williams et al. (1995) and total betalain content was determined following the method of Stintzing et al. (2003) [12,13] , whereas total carotenoid content was estimated using the procedure described by Rangana (2014). The colour characteristics of the samples were measured in terms of L*, a*, and b* values using a Colour Flex meter with 45°/0° geometry and standard illuminant C (Hunter Lab Colour Flex 150, Hunter Associates Inc., USA). The energy value of the samples was calculated according to the method proposed by O'Shea and Maguire (1962) [9] .

Statistical Analysis:

The data analysis involved the use of OPSTAT software to calculate the average and variation in different attributes of beetroot based energy drink. To compare the chemical and antioxidant properties of the newly developed products with their corresponding control samples, an independent sample t-test was performed. When examining the sensory attributes, a one-way ANOVA test was employed and compared at 5 percent level of significance to identify any level of significant.

Results and Discussion

Sensory evaluation of beetroot-based energy drink Various energy drink formulations were prepared with varying ratios of beetroot juice (BJ), litchi juice (LJ), pear juice (PJ), and ashwagandha extract (AE). The treatments are denoted as E0, E1, E2, E3, and E4, each with a specific ratio of the ingredients. The sensory evaluation was conducted based on four attributes: colour, taste, consistency, and overall impression (Table 1). Colour refers to the visual appearance of any product. In all the energy drink formulations the colour scores ranged from 8.00 to 5.50, with higher scores indicating a more visually appealing colour.

Colour and consistency scores of the blended energy drink differed non-significantly in case of control (E0) energy drink and the first two formulations of energy drink (E1 and E2) but a significant decrease was observed in these two attributes in E3 and E4 formulations of energy drinks. On the other hand, when it comes to taste, the scores in all the formulations including the control ranged from 8.60 to 4.80, with higher scores representing a more favourable taste.

Control (E0) Blended (E2) Plate 1: Appearance of beetroot-based energy drink

The control (E0) energy drink had a significantly higher taste scores than blended energy drink (E1), but no significant difference in taste scores was observed in E1 and E2 energy drink with taste scores of 7.50 and 7.80 respectively. Subsequently, there was a significant decrease in taste with increase in proportion of ashwagandha extract in different formulations. Overall acceptability which provides an overall impression of the energy drink based on colour, taste, and consistency ranged from 8.60 to 4.80, with higher scores in control energy drink suggesting a better overall sensory experience followed by E2 treatment. Based on these observations, it was concluded that blended energy drink (E1 and E2)did not exhibit any significant differences in terms of colour, taste, and consistency. Therefore, treatment E2, which contained a 5 percent of ashwagandha extract was taken further for analysis in comparison with the control (E0) energy drink. Jairajpuri et al. (2012) [6] reported that orange juice blended with 6 percent ashwagandha extract was the most acceptable by a panel of judges for sensory parameters.

Chemical parameters of beetroot-based energy drink

Table 2 depicts that the total soluble solid content of control (E0) and blended energy drink (E2) was 11.00 and 10.000 brix whereas the acidity content of both the formulations of energy drink was 0.26 and 0.25 percent respectively. Further scrutiny of data reveal that that there was no significant difference in the brix acid ratio between the control (E0) energy drink (42.35%) and blended (E2) energy drink (40.49%). Similarly, a non-significant variance in the levels of total sugars, reducing sugars, and non-reducing sugars between the control energy drink (23.64%, 12.83%, and 10.81%, respectively) and blended (E2) energy drink (22.41%, 11.94%, and 10.47%, respectively). The blended energy drink (E2) exhibited a significantly higher energy content (39.20 kcal/100ml) compared to the control energy drink (35.60 kcal/100ml) with a t-value of 8.60, indicating a significant difference (p=0.009) between both treatments. This variation in energy content could be attributed to the inclusion of ashwagandha extract, which is a known source of energy. Ashwagandha extract was intentionally added to create an energy drink based on beetroot juice. Ashwagandha is known as energy boosting tonic and memory enhancer. It is mainly grown in India that is why also called Indian ginseng (Javedet al. 2023) [7] . This value of energy closely resembled to value reported by Ashraf et al. (2022) [2] who reported that beetroot energy drink contained an energy content of 35.223 Kcal/100ml.

Antioxidant properties of beetroot-based energy drink

The ascorbic acid, betacyanins, betaxanthins, total betalains, TPC, TFC, antioxidant activity as assessed by DPPH assay of beetroot blended energy drink has been presented in Table 3. A perusal of the data reveal that there were no significant difference between the control energy drink and blended energy drink (E2) in all these components. The ascorbic acid content in both control energy drink (4.76 mg/100ml) and blended (E2) energy drink (4.73 mg/100ml) did not show a significant difference. Similarly, there were no significant variations in betacyanins, betaxanthins, and total betalains levels in control energy drink with values of 30.32, 9.90 and 40.23 mg/100ml, respectively and blended (E2) energy drink with values of 30.03, 9.30 and 39.32 mg/100ml, respectively. The total phenols and flavonoids contents in the control energy drink (8.50 mg/100ml) differed non-significantly to blended (E2) energy drink (9.43 mg/100ml), Similarly, the antioxidant activity in the control (E0) energy drink (31.68%) did not significantly differ from that in blended (E2) energy drink (33.52%). These results suggested that the formulation changes made in the blended (E2) energy drink did not significantly alter the antioxidant properties of the beetroot energy drink when compared to the control energy drink.

Colour analysis of beetroot-based

The degree of lightness, or L* value, was found to be significantly lower in the blended (E2) energy drink (19.15) in this analysis when compared to the control (E0) energy drink (17.44), suggesting that the control energy (E0) drink appeared darker (Table 4). The redness intensity, or a* value, was found to have significantly decreased in the blended (E2) energy drink (10.52) as compared to the control (E0) energy drink (23.13), suggesting a change towards a less intense red colour. Furthermore, there was a significant decrease in the control energy (E0) drink (10.76) yellowness (b* value) when compared to the blended (E2) energy drink (13.62), indicating a reduction in the beverage's yellow tones. Key information about how the treatment affects the beverage's aesthetic appeal is provided by the significant variations in colour parameters that were found between both the samples. These outcomes are significant for the thesis research because they provide important information about potential shifts in consumer preferences and sensory perception regarding the colour of the beetroot energy drink. The a* values were significantly higher in control energy drink as compared to blended energy (E2) drink. This significant difference in L*, a*, b* values might be due to the blending of 5 per cent ashwagandha extract in E2 energy drink.

Conclusion

The study concluded that beetroot juice can successfully be utilized for the development of a functional energy drink. Incorporation of 5% ashwagandha extract along with litchi and pear juice produced a beverage with good sensory acceptability and enhanced energy value without adversely affecting antioxidant properties. The developed beverage exhibited appreciable levels of betalains, phenolics, flavonoids and antioxidant activity, indicating its potential as a natural functional beverage for health-conscious consumers.

References

1. AOAC. Official Methods of Analysis. 16th ed. Washington (DC): Association of Official Analytical Chemists; 2010.
2. Ashraf S, Sayeed SA, Ali R, Vohra F, Ahmed N, Alam MK. Assessment of potential benefits of functional food characteristics of beetroot energy drink and flavoured milk. Journal of Biomed Research International. 2022;2022:1-10.
3. Chhikara N, Kushwaha K, Sharma P, Gata Y, Panghal A. Bioactive compounds of beetroot and utilization in food processing industry: A critical review. Food Chemistry. 2019;272:192-200.
4. Corbo MR, Bevilacqua A, Petruzzi L, Casanova FP, Sinigaglia M. Functional beverages: The emerging side of functional foods commercial trends, research, and health implications. Comprehensive Reviews in Food Science and Food Safety. 2014;13:1192-1206.
5. Gayathry KS, John JE. Functional beverages: Special focus on anti-diabetic potential. Journal of Food Processing and Preservation. 2021;45:e15974.
6. Jairajpuri DS, Saqib Q. Fortification of orange juice with Withania somnifera and Solanum nigrum extract: A potential functional fruit beverage and its quality evaluation. Pakistan Journal of Food Sciences. 2012;25:58-65.
7. Javed S, Nazir A, Zahoor AF, Al-Huqail AA. Ashwagandha. In: Essentials of Medicinal and Aromatic Crops. 2023. p. 123-143.
8. Larmond E. Laboratory Methods for Sensory Evaluation of Foods. Ottawa: Canada Department of Agriculture; 1977.
9. O'Shea J, Maguire MF. Determination of calorific value of feedstuffs by chromic acid oxidation. Journal of the Science of Food and Agriculture. 1962;13(10):530-534.
10. Ranganna S. Handbook of Analysis and Quality Control for Fruit and Vegetable Products. 2nd ed. New Delhi: Tata McGraw-Hill Publishing Co. Ltd.; 2014.
11. Singleton VL, Orthofer R, Lamuela-Raventós RM. Analysis of total phenols and other oxidation substrates and antioxidants by means of Folin-Ciocalteu reagent. Methods in Enzymology. 1999;299:152-178.
12. Stintzing FC, Schieber A, Carle R. Evaluation of colour properties and chemical quality parameters of cactus juices. European Food Research and Technology. 2003;216(4):303-311.
13. Williams WB, Cuvelier ME, Berset C. Use of a free radical method to evaluate antioxidant activity. LWTFood Science and Technology. 1995;28(1):25-30.
14. Zhishen J, Mengcheng T, Jianming W. The determination of flavonoid contents in mulberry and their scavenging effects on superoxide radicals. Food Chemistry. 1999;64:555-559.
15. Wootton-Beard PC, Ryan L. A beetroot juice shot is a significant and convenient source of bioaccessible antioxidants. Journal of Functional Foods. 2011;3(4):329-334.
16. Ranganna S. Handbook of Analysis and Quality Control for Fruit and Vegetable Products. 2nd ed. New Delhi: Tata McGraw-Hill Publishing Co. Ltd.; 2007.
17. Ranganna S. Handbook of Analysis and Quality Control for Fruit and Vegetable Products. 2nd ed. New Delhi: Tata McGraw-Hill Publishing Co. Ltd.; 2014.
18. Lane JH, Eynon L. Determination of reducing sugars by Fehling's solution with methylene blue indicator. Journal of the Society of Chemical Industry. 1923;42:32T-37T.