Alfalfa sprout flour: A promising ingredient to improve probiotic survival and antioxidant activity in mint-flavored stirred yogurt

• Alfalfa sprout flour (ASF) is rich in phenolic compounds and nutrients. • ASF could enhance the survival of L. acidophilus in flavored stirred yogurt. • Yogurt with ASF shows lower syneresis compared to the control. • ASF improves the antioxidant activity and total phenol content of stirred yogurt. • High concentration of ASF (1%) negatively affects the odor and flavor. This study examined the impact of alfalfa sprout flour (ASF) on the pH, titratable acidity (TA), syneresis, water-holding capacity (WHC), color attributes, antioxidant potential, survival of Lactobacillus acidophilus LA-5, and sensory properties of mint-flavored stirred yogurt over 24 days of cold storage. Four probiotic yogurt batches were prepared, namely plain probiotic yogurt (PPY), mint-flavored probiotic yogurt (MFPY), and MFPY with 0.5 and 1% w/w of ASF (MFPY-ASF-0.5%, and MFPY-ASF-1%). Yogurt with added ASF exhibited the highest increase in TA (18.80-24.40%) and a decrease in pH (0.18). L. acidophilus maintained the highest survival rate (7.3-7.43 Log CFU/g) in MFPY-ASF-1% yogurt between days 8 to 24 of storage, exceeding the minimum count recommended for the therapeutic effects of probiotics. PPY and MFPY demonstrated significantly lower WHC and higher syneresis values compared to MFPY-ASF-0.5% and MFPY-ASF-1% ( P < 0.05). The addition of mint and ASF remarkably decreased lightness ( L *) and increased yellowness ( b* ) and greenness (- a* ) values of samples compared to PPY. All flavored samples exhibited a gradual decrease in b* and -a* values, alongside an increase in L* values, during storage. ASF-enriched yogurts showed high total phenol content, total flavonoid content, and antioxidant activity. Although an increase in ASF levels resulted in a reduction in consumer preferences for odor and flavor, all samples received satisfactory overall acceptability scores (3.05-4.30) at the end of storage. In conclusion, the inclusion of ASF at the 1% level presents a promising opportunity for producing value-added yogurt with enhanced probiotic survival, antioxidant activity, and favorable technological properties.