05). Meanwhile, it reduced significantly the firmness and consistency, but not the cohesiveness, of whole yoghurts co-fermented by L. acidophilus L10. As expected, in general, all texture parameters significantly increased during cold storage, being the most marked increase observed after 1 and 14 days. Garcia-Perez et al. (2006) found that the addition of orange fiber below 1% concentration reduce the firmness of skim yoghurt. However, the present study shows that at the end of storage, firmness and consistency Selleck Vorinostat in all passion fruit peel powder skim yoghurts were higher than in their respective controls, except when using L. acidophilus NCFM as
probiotic, while their cohesiveness was increased by the addition of the PFPP in all cases. As regards the whole yoghurts, firmness was higher in controls co-fermented by L. acidophilus NCFM and B. lactis strains (P < 0.05), while consistency and cohesiveness were significantly higher in the same yoghurts but that co-fermented by B. lactis Bl04. According to Damin et al. (2008), the firmness is higher in yoghurts lasting longer fermentation time. However, Lumacaftor research buy in the present study skim yoghurts co-fermented by lactobacilli – in spite of the longer fermentation time – did not show any firmness increase after
1 day of cold storage compared to the other treatments. Cultures of lactic acid bacteria producer of exopolysaccharides (EPS) have been used to improve the texture of yoghurts (Sodini et al., 2004 and Welman and Maddox, 2003). However, the high counts of EPS-producing L. acidophilus and
S. thermophilus in skim yoghurts did not correspond to any increase in their textural parameters. This observation can be explained with the formation of a few weak polysaccharide–protein interactions instead of more stable protein–protein ones ( Folkenberg et al., 2006 and Ramchandran and Shah, 2009), which may have contributed to lowering the firmness of yoghurts. The results of the present study GNA12 taken together suggest that the textural parameters were influenced by a combination of factors such as culture composition, milk type and passion fruit peel powder addition, which justifies further efforts in this field. Results demonstrated that PFPP reduced significantly the maximum acidification rate in both skim and whole milks and reduced the fermentation time in all skim yoghurts, except the one fermented with B. lactis Bl04. Total titratable acidity was higher in skim yoghurts, especially in those with PFPP, indicating a lower buffering capacity of the skim milk regarding the whole one. In general, skim yoghurts presented higher counts of probiotic bacteria than the whole ones. The yoghurts with passion fruit peel powder had variable counts of probiotics but similar to those of control yoghurts in most of the cases. Passion fruit peel powder increased cohesiveness of all probiotic skim yoghurts.