The study – published in LWT - Food Science and Technology – investigated the antioxidant effects of lentils on lactic acid and probiotic bacteria growth in yoghurt products.
Led by Farah Hosseinian from Carleton University, Canada, the research team added ground up samples of green and red lentils to a pasteurised probiotic yoghurt product containing microbial starter cultures, finding that yoghurts containing 0-4% lentil powder maintained a stable yoghurt product with an even and consistent texture, and resulted in an increased population of probiotic bacteria.
“Overall, lentils show promise as a new and valuable component in fermented dairy products by promoting the growth of beneficial bacteria while also providing antioxidative benefits,” said Hosseinian and her colleagues.
“Results of this study demonstrate that green lentils selectively enhanced the number of probiotic bacteria in yoghurt in the initial stages of storage and maintained overall microbial counts (starter cultures and probiotics) over a 28-day storage period,” they revealed.
Hosseinian suggested an optimal concentration of lentil to be added to milk without disrupting yoghurt formation is 4%, noting that yoghurts prepared with 6% ground green lentils “resulted in excessive fermentation and the milk curdled in a manner resembling spoiled yoghurt.”
The researchers noted that the addition of prebiotic sources such as inulin has also been shown to improve the stability and sensory characterization of yogurt products, however to date, research on the prebiotic potential of lentils is very limited and none have investigated their effects on the growth rate of probiotics when incorporated in yogurt.
As a result, Hosseinian and her colleagues evaluated the antioxidant potential of lentil polysaccharides in stimulating the growth of probiotic bacteria in yogurt. The team measured microbial counts, pH and total titratable acidity (TTA) in yogurt samples containing starter cultures with or without probiotic bacteria. The samples were supplemented with, or without, ground lentils.
Hosseinian revealed that the green lentils selectively enhanced the number of probiotic bacteria in yogurt in initial stages of storage, and helped to maintain overall counts of microbes - including probiotics and starter cultures - over 28-days.
“Furthermore, the overall reduction in pH and increase in TTA in lentil containing yogurt samples after the 28-day storage period at 4 °C, suggest that starter cultures preferentially utilize lentils toward the end of this storage period.”
The team said future studies with animal models and human clinical trials are necessary to determine any health-related properties of yogurt and other fermented dairy products containing lentils.
Source: LWT - Food Science and Technology
Published online ahead of print, doi: 10.1016/j.lwt.2012.07.032
“Lentils enhance probiotic growth in yogurt and provide added benefit of antioxidant protection”
Authors: Rania Agil, Aline Gaget, Julia Gliwa, Tyler J. Avis, William G. Willmore, Farah Hosseinian