In this study, antioxidant, chemical, microbiological, and sensory attributes changes taking place during the production of probiotic yoghurt using pulp of soursop (Annona muricata), sweetsop (Annona squamosa), and custard apple (Annona reticulata) were evaluated. The products were stored at 4 °C for 28 d, during which time physicochemical properties and viability of probiotic bacteria and yoghurt starter cultures were evaluated weekly. Yoghurts prepared with fruit pulps displayed higher antioxidant activities on the first day of storage compared to the control. During the storage, the addition of fruit pulps influenced (p < 0.05) pH, titratable acidity, syneresis and counts of B. animalis ssp. lactis BB-12 of yoghurts, whereas counts of Streptococcus thermophiles and Lactobacillus delbrueckii ssp. bulgaricus were found to be insignificant. Sensory evaluation results showed that yoghurt containing soursop fruit pulp had better sensory scores than other treatments. Therefore, these results proved that soursop can be used to produce probiotic yoghurt with enhanced physicochemical, microbiological and sensory properties.

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In the current study, the effect of two exopolysaccharide (EPS) producing starter cultures (YF‐L903 and YC‐X11) and a commercial starter culture (STI‐12) on the physicochemical, microbiological, and sensory attributes of probiotic goats' milk set‐yoghurt was evaluated after processing and storage at 4°C for 28 days. The type of starter culture had no effect (p > .05) on acidification of set‐yoghurts. There were no differences (p > .05) in terms of viable cell counts in two tested set‐yoghurts; more or less similar final cell counts were observed for Bifidobacterium animalis subsp. lactis BB‐12 (~7.9 log cfu/g), Streptococcus thermophilus (~8.2 log cfu/g), and Lactobacillus delbrueckii subsp. bulgaricus (~7.8 log cfu/g). In situ EPS production of the starter cultures resulted goats' milk set‐yoghurt with low syneresis, high apparent viscosity, and improved sensory attributes. Practical applications This study showed that in situ EPS production by EPS producing starter cultures markedly improved the quality attributes of goats' milk set‐yoghurt. EPS production of starter cultures significantly reduced syneresis and improved apparent viscosity and sensory attributes of goats' milk set‐yoghurt. This work can have an impact in advancing our understanding of the role of EPS producing starter within the context of goats' milk set‐yoghurt production and in developing improved fermented goats' milk based dairy products. There is very little microbiological and physicochemical information on goats' milk set‐yoghurt produced with EPS producing strains, and little understanding on the role of the produced EPS. To the best of our knowledge this is the first study investigating the microbiological and physicochemical characteristics of goats' milk set yoghurts produced with the help of EPS producing starter cultures. Therefore, we believe that this work can have an impact in advancing our understanding of the role of EPS producing starter within the context of goats' milk yoghurt production and in developing improved fermented goats' milk based dairy products.

Hydrocolloids can act as gluten substitutes to form the structural equivalents of the gluten network in gluten-free bakery products. “Purple yam” (Dioscorea alata) is one of the underutilized yams in Sri Lanka with high nutritional potential. The overall objective of this study was to develop gluten-free muffins using “Purple yam” (Dioscorea alata) flour with hydrocolloids (pectin, xanthan gum, and guar gum) and investigate the nutritional composition and selected properties of the muffins. The texture profiles of gluten-free muffins were analyzed through the following parameters: hardness, adhesiveness, cohesiveness, etc. The chromameter values were obtained and sensory evaluations for gluten-free muffins were carried out. The highest moisture content was recorded in pectin-incorporated muffins ( 17.70 ± 0.50 % ). The protein content of all three types of muffins was around 5%. The highest fat content was recorded in pectin-incorporated muffins ( 19.26 ± 0.51 % ). The ash content of all three types of muffins was around 2%. Potassium was the most predominant element found in each muffin. The hardness of guar gum-incorporated muffin ( 6379.3 ± 135.9   g ) was greater than that of the pectin-incorporated one ( 6082.3 ± 23.4   g ). Xanthan gum-incorporated muffins had significantly decreased cohesiveness ( 0.19 ± 0.04 ). The highest springiness was obtained in pectin-incorporated muffin ( 37.13 ± 1.61   mm ). The descending order of the chewiness of muffin is pectin − added > xanthan   gum − added > guar   gum − added sample. According to the sensory evaluation, pectin-incorporated muffin was the best as it had obtained the highest sum of ranks for appearance, color, taste, after taste, and overall acceptability.