Lentil (Lens culinaris) flour addition to yogurt: Impact on physicochemical, microbiological and sensory attributes during refrigeration storage and microstructure changes

Abstract

This study aims to assess the quality attributes of lentil flour fortified yoghurt during cold storage (6 ± 2 °C) for 21 days. Yogurt formulation was based on the addition of roasted and unroasted lentil flour at rate of 4%. Three formulations (first and the second treatments were prepared with the addition of unroasted and roasted lentil flour (ULF and RLF), respectively and third one plain yogurt) were prepared from partially skimmed cow milk and fermented with specific thermophilic bacteria of yogurt. The physicochemical (pH, titratable acidity and dry extract), microbiological quality and sensory acceptance were evaluated through the entire storage period. Lentil flours structure (roasted and unroasted) has been observed, before and after addition in the yogurt, by scanning electron microscope (SEM). Results showed that addition of lentil flour significantly (p < 0.05) affected the physicochemical and sensorial properties of fortified yogurts. Low syneresis value was observed in yogurt with unroasted and roasted lentil flour, respectively compared with the control. While, the microbiological analysis showed that the yogurts are of satisfactory quality. The most preferred yogurt was the one incorporated with unroasted lentil flour. The SEM observations of lentil flours before and after addition in yogurt found the significant changes in their morphology structure.