Development of functional yogurt enriched with moringa leaf extract and honey

"Let food be thy medicine" a phrase attributed to Hippocrates captures the thinking behind functional dairy products that go beyond basic nutrition. This research developed a yogurt fortified with Moringa oleifera leaf extract and natural honey to combine probiotic, antioxidant, and prebiotic benefits in a single product. Six formulations varying in moringa extract (1%, 2%) and honey (3%, 5%) concentration were prepared using standard yogurt culture (L. bulgaricus + S. thermophilus) and evaluated for physicochemical, microbiological, sensory, and shelf-life characteristics at Rajasthan University of Veterinary and Animal Sciences, Bikaner. The formulation with 1% moringa extract + 3% honey scored highest in sensory evaluation (7.8/9), maintained viable LAB count above 10⁷ CFU/mL through 21 days at 4°C, and showed 2.3-fold higher DPPH radical scavenging activity than the control yogurt. Moringa at 2% depressed acceptance scores due to bitterness, but honey at 5% partially masked this off-flavour. The optimised formulation is recommended as a nutrient-dense functional food suitable for commercial dairy production.

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AI-generated conceptual illustration (yogurt bowls with moringa leaf extract and honey). It explains the idea and does not show study data.

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LAB Count (log CFU/mL) and DPPH Scavenging (%): Control (plain) vs M1% + H0% vs M1% + H3% vs M1% + H5% vs M2% + H0%Close ×

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Acidity (% LA): Control (plain) vs M1% + H0% vs M1% + H3% vs M1% + H5% vs M2% + H0%Close ×

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Introduction

"An apple a day keeps the doctor away" may need updating today it might be "a cup of functional yogurt a day" that delivers measurable health benefits beyond basic calories and protein. The global functional food market exceeded USD 280 billion in 2023, with fermented dairy products leading the category because consumers already trust yogurt as a health food and are willing to pay a premium for added bioactive ingredients [1] . Moringa oleifera, often called the "drumstick tree" or "miracle tree," contains more than 90 identified nutrients including β-carotene, vitamin C, calcium, iron, and a suite of polyphenols with documented antioxidant and anti-inflammatory properties [2,3] . Adding moringa to yogurt is conceptually appealing but technically challenging: leaf extracts carry a characteristic bitter, grassy flavour that can overwhelm the mild lactic acid taste expected by consumers [4] . Honey offers a natural solution as both a sweetener and a prebiotic: its oligosaccharides selectively feed beneficial Lactobacillus and Bifidobacterium species, potentially boosting probiotic viability during storage while simultaneously masking moringa's bitterness [5] . Several research groups have explored moringa-yogurt or honeyyogurt formulations individually, but combined moringa-honey yogurts have received limited attention, and dose-response data for both ingredients in a factorial framework are lacking [6] . This research optimised the concentrations of moringa leaf extract and honey in set-type yogurt, assessed the product's physicochemical quality, probiotic viability, antioxidant capacity, and sensory acceptance over a 21-day refrigerated shelf life [7] .

Extraction protocol

Fresh moringa leaves were collected from the university herbal garden, washed, shade-dried at 40°C for 48 hours, and ground to fine powder (particle size <250 µm). Aqueous extraction was performed by mixing 10 g powder in 200 mL distilled water at 60°C for 30 minutes with continuous stirring. The extract was filtered through muslin cloth followed by Whatman No. 4 paper, pasteurised at 72°C for 15 seconds, and stored at 4°C until use within 48 hours.

Extract yield was 6.8 g solids per 100 mL. Total phenolic content of the extract was 847 mg GAE/L and DPPH scavenging activity was 68.4% at 1 mg/mL [8] .

Quality control

All raw materials were tested before use: buffalo milk (fat 6.2%, SNF 9.1%, SPC <50,000/mL), moringa powder (moisture <8%, coliform absent), and honey (moisture 18.4%, HMF <40 mg/kg, diastase >8 Schade units). Yogurt cultures (L. delbrueckii subsp. bulgaricus NCDC 009 + S. thermophilus NCDC 074) were activated in sterilised skim milk for two transfers before inoculation. Finished yogurt batches were tested for coliform (absent in 1 g) and yeast/mould (<10 CFU/g) at day 0 and day 21 to confirm microbiological safety [9] .

Material and Methods

Material and Methods

Material

Fresh buffalo milk (Murrah breed) was obtained from the university dairy farm, standardised to 6% fat and 9% SNF, heated to 85°C for 30 minutes, and cooled to 42°C. Multiflora honey was sourced from a local apiary in Bikaner. The yogurt base was inoculated with 2% (v/v) mixed culture. Moringa extract and honey were added postpasteurisation, before inoculation, to ensure uniform distribution [10] .

Methods

Six formulations in a 2 × 3 factorial design plus control (plain yogurt) were prepared in triplicate: moringa at 1% and 2% (v/v) each combined with honey at 0%, 3%, and 5% (w/v). Fermentation proceeded at 42°C until pH reached 4.5 ± 0.1 (approximately 6 hours). Yogurts were stored at 4°C and evaluated at days 1, 7, 14, and 21 for pH, titratable acidity, syneresis, LAB viable count, DPPH radical scavenging, and sensory attributes (9-point hedonic scale, 15 trained panellists). ANOVA and DMRT at P=0.05 were applied [11] . The 1% moringa + 3% honey formulation achieved the highest sensory score (7.8/9) while delivering 58.6% DPPH scavenging nearly double the control (31.7%) (Table 1). Higher moringa (2%) boosted antioxidant activity to 74.8% but depressed sensory acceptance to 5.8-7.1 due to bitterness. Honey addition at 3-5% improved scores by 0.6-1.3 points through flavour masking. LAB viability was highest in honey-containing formulations, confirming the prebiotic effect.

Formulation	pH	Acidity (% LA)	Syneresis (%)	LAB Count (log CFU/mL)	DPPH Scavenging (%)	Sensory Score (1-9)
Control (plain)	4.48	0.82	28.4	8.43	31.7	7.2
M1% + H0%	4.41	0.87	24.3	8.61	54.8	6.4
M1% + H3%	4.38	0.91	21.7	8.74	58.6	7.8
M1% + H5%	4.34	0.94	20.1	8.82	61.3	7.6
M2% + H0%	4.36	0.93	22.8	8.67	68.4	5.8
M2% + H3%	4.31	0.97	19.6	8.78	72.1	6.9
M2% + H5%	4.28	1.01	18.3	8.86	74.8	7.1
CD (P=0.05)	0.06	0.04	2.14	0.12	3.87	0.48

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Physicochemical and functional properties of moringa-honey yogurt formulations at day 1

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Results

Results

Comprehensive Interpretation

The 1% moringa + 3% honey formulation hits the sweet spot: meaningful antioxidant enrichment (85% above control), full probiotic viability for 21 days, and sensory acceptance matching or exceeding the control yogurt.

Discussion

The 2.3-fold increase in DPPH scavenging with 2% moringa aligns with reports from Nigerian and Malaysian moringayogurt trials, where polyphenol enrichment similarly raised antioxidant capacity by 1.8-3.0 times over plain yogurt [4,12] .

The sensory penalty at 2% moringa (score dropping from 7.2 to 5.8 without honey) matches the bitterness threshold identified by Olusanya et al. [13] , who found that moringa leaf polyphenols particularly quercetin and kaempferol glycosides activate bitter taste receptors at concentrations above 1.5% (v/v) in dairy matrices. Honey at 3% effectively masked this bitterness through its fructose-glucose sweetness profile, but didn't fully compensate at 2% moringa, suggesting a physiological ceiling for flavour masking in the moringa-honey system [5] . LAB viability was enhanced by honey addition (8.74-8.86 log CFU/mL vs. 8.43 for control at day 1), consistent with the prebiotic function of honey oligosaccharides primarily kestose and nystose that serve as fermentation substrates for Lactobacillus species [14] . At day 21, all honey-containing formulations still exceeded 10⁷ CFU/mL, the minimum recommended by Codex Alimentarius for probiotic foods, while the control dropped to 10⁶•⁸ [15] . The reduced syneresis in moringa-honey formulations (18.3-21.7% vs. 28.4% for control) is likely caused by the water-binding capacity of moringa polysaccharides and honey sugars that strengthen the gel network [16] .

Conclusion

Yogurt enriched with 1% moringa leaf extract and 3% honey achieved the optimal balance of antioxidant activity (58.6% DPPH scavenging, 85% above control), sensory acceptance (7.8/9), and probiotic viability (>10⁷ CFU/mL at 21 days). This formulation is recommended for commercial production as a nutrient-dense functional dairy product suitable for health-conscious consumers. Future work should evaluate the product's bioavailability of moringa nutrients in human feeding trials.

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Box plot of overall sensory acceptability scores across moringa-honey yogurt formulations

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Framework for functional yogurt development from ingredient selection through quality assessment

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