Impact of carob (Ceratonia siliqua L.) pulp flour supplementation on probiotic viability, milk fermentation and antioxidant capacity during yogurt storage

Abstract

The aim of this study was to investigate the effect of carob pulp flour addition on probiotic viability, milk fermentation (pH, acidity and syneresis) and antioxidant activity, during yogurt cold storage (4 °C, 28 days). Methods: Four types of yogurts were prepared: plain yogurt (Y); yogurt with carob pulp flour (YC); yogurt with probiotic (YP) and yogurt with carob pulp flour and probiotic (YPC). Results: Ceratonia siliqua L. pulp flour supplementation (4% w/v) increased probiotic survival (15.96 %), titratable acidity (27.65 %) and syneresis (30.13 %). Carob pulp flour improved antioxidant activity for both DPPH (62.8 %) and iron chelating test (35.81 %), where yogurt containing probiotic and carob exhibited the highest antioxidant activity. Carob pulp flour had a selective effect on probiotic growth implying its prebiotic potential. Probiotic bacteria were viable and available at high concentration (> 106 CFU/mL) at 28 day storage to sustain human health. Conclusion: Our results show that Algerian Carob can be considered as a very potential prebiotic, stimulating the growth of beneficial bacteria and exert strong antioxidant activity due to the presence of polyphenols.