Studies on optimization and sensory evaluation of lassi blended with dragon fruit (Selenicereus Undatus) pulp

Introduction

Milk and milk-based products have long been recognized as essential components of human nutrition due to their balanced composition and high biological value. In recent years, consumer demand has shifted toward functional foods that offer additional health benefits beyond basic nutrition. Fermented dairy beverages such as lassi provide an excellent medium for incorporating natural ingredients like fruit pulps to enhance their nutritional and sensory properties (Tamime et al., 2007) [1] . Lassi is a traditional fermented milk beverage widely consumed across India and South Asia. It is prepared by blending curd (dahi) with water, sugar and optional flavouring agents. The beverage is valued for its probiotic properties, pleasant taste, cooling character and therapeutic attributes (Aneja et al., 2002; Panesar, 2011) [2,3] . The growing popularity of fruit-flavoured lassi varieties has opened new avenues for the development of functional dairy beverages with enhanced nutritional and sensory profiles (Patel et al., 2013) [4] . Dragon fruit (Selenicereus undatus), belonging to the family Cactaceae, is an exotic tropical fruit gaining widespread popularity due to its striking pink appearance and high therapeutic value. It is rich in natural betalain pigments, polyphenolic compounds, flavonoids, ascorbic acid, soluble dietary fibre and essential minerals including calcium, phosphorus and iron (Zainoldin et al., 2012; Siregar et al., 2023) [6,5] . Its antioxidant, anti-diabetic, hypocholesterolemic and immune-enhancing properties make it a suitable functional ingredient for dairy product fortification (Pavithra et al., 2023; Hafiz et al., 2025) [8,7] . The incorporation of dragon fruit pulp into lassi serves a dual objective: it imparts a natural attractive pink hue eliminating the need for synthetic colorants, while simultaneously enriching the beverage with bioactive functional compounds. Limited research has been conducted on dragon fruit blended lassi; therefore, the present study was undertaken to optimize the level of dragon fruit pulp incorporation and evaluate the resulting sensory and physico-chemical characteristics.

Materials and Methods

Collection of raw materials

Fresh cow milk (3.5% fat, 8.5% SNF) was procured from Natural Milk Pvt. Ltd., Latur. Fresh pink dragon fruit (Selenicereus undatus) was purchased from the local market in Latur city. Standard freeze-dried dahi culture (NCDC-167) containing Lactococcus lactis and Streptococcus thermophilus was used for fermentation at 2% inoculation rate.

ISSN Print: 2617-4693 ISSN Online: 2617-4707 NAAS Rating (2026): 5.29 Indexing: Embase

Preparation of dragon fruit pulp

Fresh dragon fruit was washed, peeled and cut into small slices. The pulp was extracted by pressing through a clean muslin cloth, removing seeds to obtain clear pulp, which was stored under refrigeration until use.

Preparation of lassi

Cow milk was pasteurized at 80-85 °C for 15 minutes, cooled to 37 °C and inoculated with active dahi culture (NCDC-167) at 2% on weight basis. Inoculated milk was incubated at 30 °C for 12 hours until set curd was obtained. The coagulum was broken and blended with 20% chilled water and 15% sugar (w/w). Dragon fruit pulp was incorporated as per experimental treatments. The prepared lassi was packed in sanitized glass bottles and stored at 7 ± 2 °C.

Treatment combinations

Four experimental treatments were formulated on a weight-by-weight basis as follows: T 0: 100 parts curd (Control, 0% dragon fruit pulp) T 1: 98 parts curd + 2 parts dragon fruit pulp T 2: 96 parts curd + 4 parts dragon fruit pulp T 3: 94 parts curd + 6 parts dragon fruit pulp

Sensory evaluation

Sensory evaluation was performed by a semi-trained panel of judges using a 9-point Hedonic scale (9 = Like extremely; 1 = Dislike extremely) as per the Quartermaster Food and Container Institute, USA. Evaluated parameters included colour and appearance, flavour, taste, body and texture, and overall acceptability.

Physico-chemical analysis

Titratable acidity was determined by IS: 1479 (1960) Part-I. pH was measured using a digital pH meter (EUTECH Instruments, Model 335). Fat content was determined by Gerber's method (IS: 1224, Part II, 1977). Protein was estimated using the Lowry method (Lowry et al., 1951) [9] . Moisture and total solids were determined by IS: SP (Part XI) 1981. Ash content was estimated by ignition in a muffle furnace at 550 °C as per IS: SP (Part XI) 1981.

Statistical analysis

All experimental data were statistically analysed using a Completely Randomized Design (CRD) with four replications per treatment, following the method of Panse et al. (1985) [10] . Significance of treatment differences was evaluated using Critical Difference (CD) at 5% level of probability.

Procedure

The fresh dragon fruit purchased from the local market was washed thoroughly and stored in the refrigerator. It was then peeled and cut into small slices. The slices were churned and pressed through a clean muslin cloth, collecting the pulp in a beaker and separating the seeds. The extracted pulp was stored under refrigeration until further use. For preparation of lassi blended with dragon fruit pulp, the cow milk was heated at 80-85 °C for 15 minutes and cooled to 37 °C. After cooling, standard dahi culture NCDC-167 @ 2 per cent (w/w) was added to the milk, which was then incubated at 30 °C for 12 hours to obtain set curd. The coagulum was broken and chilled water (20%) was added. Dragon fruit pulp was blended into the lassi as per the respective treatment combinations (T 0: 0%, T 1: 2%, T 2: 4%, T 3: 6% on weight basis) and churned using an electric churner. Sugar (15% by weight of lassi) was mixed uniformly. The prepared lassi was packed in sanitized glass bottles and stored at 7 ± 2 °C for further sensory and physico-chemical analysis.

Results and Discussion

Chemical composition of raw materials

The cow milk used in the study contained 3.50% fat, 8.50% SNF, 3.30% protein, 4.70% lactose, 87.80% moisture and 12.20% total solids, confirming compliance with FSSAI standards for standardized whole cow milk. The dragon fruit pulp contained 87.10 g moisture, 1.10 g protein, 0.57 g fat, 11.20 g carbohydrates, 2.80 g dietary fibre, 20.50 mg vitamin C, 8.50 mg calcium, 22.50 mg phosphorus and 1.90 mg iron per 100 g. These values are consistent with those reported by Sonawane (2017) and Siregar et al. (2023) [5] .

Sensory evaluation

Colour and appearance

The mean colour and appearance scores for T 0 , T 1 , T 2 and T 3 were 6.80, 7.50, 8.49 and 8.71, respectively (Table 1). The treatment effect was statistically significant (𝐹 cal = 29.1198 > 𝐹 table = 3.4903; CD at 5% = 0.5079). All four treatments differed significantly from one another (superscripts a, b, c, d). The progressive increase in scores with pulp level reflects the visually attractive pink-red colour imparted by the natural betalain pigments of dragon fruit pulp, which dispersed uniformly in the aqueous phase of lassi without precipitation. These findings agree with Kedaree et al. (2021) [11] , Jayasinghe et al. (2015) [12] and Aiswarya et al. (2025) [13] , who reported significant improvement in colour scores with increasing fruit pulp incorporation in fermented dairy products. Means with different superscripts differ significantly (p < 0.05)

Flavour

The mean flavour scores for T 0 , T 1 , T 2 and T 3 were 7.78, 8.23, 8.43 and 8.37, respectively (Table 2). T 2 recorded the highest numerical score (8.43), followed by T 3 , T 1 and T 0 . ANOVA indicated a non-significant treatment effect (𝐹 cal = 2.2401 < 𝐹 table = 3.4903), and all treatments were statistically at par (superscript 'a'). The mild fruity aromatic notes of dragon fruit pulp complemented the lactic acid flavour profile generated by the starter culture, providing a pleasant refreshing taste. These observations are in agreement with Khairnar et al. (2025) [14] and Jayasinghe et al. (2015) [12] .

Taste

Taste scores for T 0 , T 1 , T 2 and T 3 were 7.50, 7.77, 8.58 and 8.49, respectively (Table 3). T 2 (4% pulp) registered the highest mean score (8.58), followed by T 3 (8.49), T 1 (7.77) and T 0 (7.50). ANOVA showed a significant treatment effect ( 𝐹 cal = 10.8517 > 𝐹 table = 3.4903; CD at 5% = 0.4964), with T 0 and T 1 statistically at par and T 2 and T 3 at par and superior to T 0 and T 1 .

The slight decline in taste at 6% pulp may be related to higher acidity at elevated pulp levels. These results are consistent with Dhumal et al.

(2018) [15] , who observed a similar pattern of taste improvement up to an optimum level followed by a decline.

Body and texture

Body and texture scores were 7.65, 8.50, 8.15 and 8.00 for T 0 , T 1 , T 2 and T 3 , respectively (Table 4). T 1 (2% pulp) recorded the highest numerical score (8.50), followed by T 2 (8.15), T 3 (8.00) and T 0 (7.65) (2018) [16] and Jadhav (2016).

Means with different superscripts differ significantly (p < 0.05)

Overall acceptability

Overall acceptability scores ranged from 7.70 (T 0 ) to 8.58 (T 2 ). The mean scores for T 0 , T 1 , T [12] , Khairnar et al. (2025) [14] and Aiswarya et al. (2025) [13] . Means with different superscripts differ significantly (p < 0.05)

Physico-chemical properties

Titratable acidity

Titratable acidity increased progressively from 0.82% (T 0 ) to 0.84% (T 1 ), 0.89% (T 2 ) and 0.91% (T 3 ) (Table 6). The treatment effect was significant (𝐹 cal = 33.0526 > 𝐹 table = 3.4903; CD at 5% = 0.0237), with T 2 and T 3 statistically at par. The increase in acidity is attributed to the organic acids naturally present in dragon fruit pulp. These findings are consistent with Upadhyay et al. (2017) [17] and Siregar et al. (2023) [5] . Means with different superscripts differ significantly (p < 0.05)

pH

pH values declined progressively from 4.56 (T 0 ) to 4.43 (T 1 ), 4.37 (T 2 ) and 4.29 (T 3 ) (Table 7). The treatment effect was significant ( 𝐹 cal = 35.5044 > 𝐹 table = 3.4903), with T 1 and T 2 statistically at par. The decrease in pH corresponds with the progressive increase in titratable acidity upon dragon fruit pulp incorporation. A lower product pH enhances microbiological safety by suppressing pathogenic microorganisms, thereby extending storage stability. Similar results were reported by Ghule et al. (2015) [18] , Hafiz et al. (2025) [7] and Dhumal et al. (2018) [15] .

Fat content

Fat content decreased progressively from 2.55% (T 0 ) to 2.51% (T 1 ), 2.47% (T 2 ) and 2.44% (T 3 ) (Table 8). The treatment effect was significant (𝐹 cal = 14.0571 > 𝐹 table = 3.4903; CD at 5% = 0.0372). The ob-served reduction is attributed to the comparatively low fat content (0.57 g/100 g) of dragon fruit pulp and the dilution effect of increasing pulp levels. Comparable results were reported by Dhumal et al. (2018) [15] and Kahandal et al. (2020) [19] .

Protein content

Protein content decreased progressively from 3.13% (T 0 ) to 2.95% (T 1 ), 2.81% (T 2 ) and 2.71% (T 3 ) (Table 9). ANOVA indicated a highly significant treatment effect (𝐹 cal = 94.019 > 𝐹 table = 3.4903;

CD at 5% = 0.0576), with all four treatments differing significantly from one another. The reduction is associated with the comparatively low protein content (1.10 g/100 g) of dragon fruit pulp compared to the cow milk base (3.30%). Comparable findings were reported by Kahandal et al. (2020) [19] .

Moisture content

Moisture content increased from 87.21% (T 0 ) to 88.59% (T 1 ), 89.50% (T 2 ) and 89.65% (T 3 ) (Table 10). The treatment effect was significant (𝐹 cal = 12.7484 > 𝐹 table = 3.4903; CD at 5% = 0.9664), with T 1 , T 2 and T 3 statistically at par while T 0 differed significantly. The increase is consistent with the high moisture content of fresh dragon fruit pulp (87.10 g/100 g). Comparable results were reported by Dhumal et al. (2018) [15] .

Total solids

Total solids decreased from 12.79% (T 0 ) to 11.41% (T 1 ), 10.50% (T 2 ) and 10.35% (T 3 ) (Table 11). The treatment effect was significant ( 𝐹 cal = 12.7484 > 𝐹 table = 3.4903), with T 1 , T 2 and T 3 statistically at par while T 0 differed significantly. The decrease in total solids corresponds with the increase in moisture content, attributable to the high moisture content and comparatively lower total solids of fresh dragon fruit pulp. These findings are comparable with Mule et al. (2018) [16] and Bagal et al. (2016) [20] .

Ash content

Ash content increased numerically from 1.25% (T 0 ) to 1.36% (T 1 ), 1.44% (T 2 ) and 1.58% (T 3 ) with ANOVA showing a significant treatment effect (𝐹 cal = 51.127 > 𝐹 table = 3.4903). The increase in ash is attributed to the mineral contribution of dragon fruit pulp (calcium, phosphorus, iron), which supplemented the intrinsic mineral profile of the cow milk base, thereby increasing overall mineral residue upon ignition. This mineral enrichment represents a nutritional advantage of dragon fruit pulp incorporation into lassi.

Conclusion

The present study demonstrated that dragon fruit (Selenicereus undatus) pulp can be successfully incorporated into lassi at levels of 2-6% without adversely affecting product quality. Colour and appearance improved significantly with increasing pulp level, with T 3 (6% pulp) recording the highest score (8.71). Flavour scores improved numerically but non-significantly. Taste and overall acceptability were significantly influenced, with T 2 (4% pulp) recording the highest scores of 8.58 in both parameters. Physico-chemical analysis revealed progressive increases in acidity and ash, and decreases in fat, protein and total solids with increasing pulp incorporation. On the basis of highest overall acceptability (8.58) and favourable physico-chemical charac-teristics, T 2 (4% dragon fruit pulp) was identified as the optimum formulation. The study demonstrates the feasibility of developing a naturally coloured, nutritionally enriched and sensory-acceptable functional fermented dairy beverage by incorporating 4% dragon fruit pulp into lassi.

References

1. Tamime AY, Robinson RK. Yoghurt: Science and technology. Woodhead Publishing; 2007.
2. Aneja RP, Mathur BN, Chandan RC, Banerjee AK. Technology of Indian milk products. Dairy India Publications. 2002.
3. Panesar PS. Fermented dairy products. Food Science and Technology. 2011;2(3):123-130.
4. Patel A, Prajapati JB. Food and health applications of fermented dairy products. International Journal of Dairy Technology. 2013;66(3):291-299.
5. Siregar SF, Apriantini A, Soenarno MS. Physicochemical properties, antioxidant activity and organoleptic of yogurt with addition of red dragon fruit juice. Jurnal Ilmu Produksi dan Teknologi Hasil Peternakan. 2023;11(3):141-152.
6. Zainoldin KH, Baba AS. The effect of Hylocereus polyrhizus and Hylocereus undatus on physicochemical, proteolysis and antioxidant activity in yogurt. World Academy of Science, Engineering and Technology. 2012.
7. Hafiz MS, Karunanayaka IU, Nugraheni K, Fernando GSN. Valorisation of dragon fruit peel in drinking yoghurt. Czech Journal of Food Sciences. 2025;43(3):179-186.
8. Pavithra KJ, Mini C. Development and quality evaluation of dragon fruit (Hylocereus undatus) based blended RTS beverages. Asian Journal of Dairy and Food Research. 2023;42(1):110-116.
9. Lowry OH, Rosebrough NJ, Farr AL, Randall RJ. Protein measurement with the Folin phenol reagent. Journal of Biological Chemistry. 1951;193(1):265-275.
10. Panse VG, Sukhatme PV. Statistical methods for agricultural workers (4th ed.). Indian Council of Agricultural Research, New Delhi. 1985.
11. Kedaree VC, Nalkar SD, Deshmukh MB. Preparation of lassi blended with kiwi (Actinidia deliciosa) pulp. Journal of Pharmacognosy and Phytochemistry. 2021;10(2):768-771.
12. Jayasinghe O, Fernando S, Jayamanne V, Hettiarachchi D. Production of a novel fruit yoghurt using dragon fruit (Hylocereus undatus L.). European Scientific Journal. 2015;11(3):1857-1881.
13. Aiswarya VG, Rachana CR. Preparation and characterisation of purple dragon fruit (Hylocereus costaricensis) yogurt. International Journal of Horticulture and Food Science. 2025;7(1):149-151.
14. Khairnar SA, Kale SM, Sankpal SS, Chugh P, Patil NS. Optimization and quality evaluation of dragon fruit blended lassi. International Journal of Agriculture and Food Science. 2025;7(10):588-591.
15. Dhumal VS, Padghan PV, Shinde SP, Maske TA. Effect of pudina extract on physico-chemical properties of lassi. Journal of Pharmacognosy and Phytochemistry. 2018;7(1):2763-2766.
16. Mule SM, Kadam SS, Jadhav SR, Dandekar VS, Ramod SS. Studies on sensory evaluation of low fat lassi prepared by incorporation of lemon grass extract. International Journal of Chemical Studies. 2018;6(1):1299-1302.
17. Upadhyay S, Parimita, Kumar P. Preparation of carrot lassi. The Pharma Innovation Journal. 2017;6(8):302-305.
18. Ghule BK, Desale RJ, Gavhane MS, Khore MC. Preparation of strawberry lassi. Research Journal of Animal Husbandry and Dairy Science. 2015;6(1):22-26.
19. Kahandal SS, Shelke RR, Bawangade SS. Effect of strawberry pulp on physico-chemical properties of lassi. Journal of Pharmacognosy and Phytochemistry. 2020;9(5):527-529.
20. Bagal SV, Todkar SR, Thalkar TR. Utilization of papaya pulp for lassi preparation. Advances in Life Sciences. 2016;5(20):89638969.
21. How to cite this article: Kharat P, Andhare B, Chauhan D, Shinde A, Shinde S, Sakhare C. Studies on optimization and sensory evaluation of lassi blended with dragon fruit (Selenicereus Undatus) pulp. International Journal of Advanced Biochemistry Research. 2026;SP-10(10):164-169. doi: https://www.doi.org/10. 33545/26174693.2026.v10.i10Sc.10271