Probiotic Yoghurt Made from Milk of Ewes Fed a Diet Supplemented with Spirulina platensis or Fish Oil

Abstract

Purpose Yoghurt is a widely consumed dairy product around the world. It has healing properties and characteristics that are important for human health. Our goal was to see how using ewes' milk fed Spirulina platensis (SP) or fish oil (FO)-supplemented diets affected the chemical, physical, and nutritional properties of yoghurt, as well as the activity and survival of starter and probiotic bacteria during storage. Methods The collected milk from each ewe group was preheated to 65 °C and homogenized in a laboratory homogenizer, then heated to 90 °C for 5 min, cooled to 42 °C, and divided into two equal portions. The first portion was inoculated with 2.0% mixed starter culture (Lactobacillus bulgaricus and Streptococcus thermophilus, 1:1), whereas the second was inoculated with 2% mixed starter culture and 1% Bifidobacterium longum as a probiotic bacteria. Results SP yoghurt had the highest levels of short chain-FA, medium chain-FA, mostly C10:0, and long chain-FA, namely C16:0, C18:2 and the lowest levels of C18:0 and C18:1, followed by FO yoghurt. The addition of SP or FO to ewes' diets resulted in yoghurt with higher viable counts of L. bulgaricus and S. thermophilus, which were still >107 cfu/g at the end of storage, as well as a higher level of acetaldehyde content (P<0.05) as a flavor compound, than the control (C) yoghurt. The viscosity of SP yoghurt was higher than that of FO and C yoghurt; the difference was not significant. The addition of B. longum, a probiotic bacteria, to all yoghurt samples, improved antioxidant activities, particularly against ABTS• radicals, but reduced SP yoghurt viscosity. When B. longum was added, acetaldehyde content increased from 39.91, 90.47, and 129.31 μmol/100g in C, FA, and SP yoghurts to 46.67, 135.55, and 144.1 μmol/100g in probiotic C, FA, and SP yoghurts, respectively. There was no significant difference in sensory qualities among all the yoghurt samples during all storage periods. Conclusions Supplementing the ewes' diets with Spirulina platensis or fish oil can change the fatty acid composition of the resulting yoghurt. The starter culture's activity, flavor compounds, and some chemical, physical, and antioxidant properties of milk produced from these diets can all be improved, particularly in yoghurt treated with probiotic bacteria (B. longum).

A Thorough Investigation of the Microbiological, Physicochemical, and Sensory Properties of Ewe’s Yoghurt Fermented by a Selected Multi-Strain Starter Culture

“…After fermentation, the final yoghurts show count loads one log cycle higher than inoculums ( S. thermophilus and L. delbrueckii were detected at 8.84 and 8.35 CFU/g, respectively, in EY-1 and 9.00 and 8.54 in EY-2). Similar results can be found in the work of Shazly et al [ 69 ], who produced probiotic yoghurt from ewe’s milk. Birollo et al [ 70 ] stated that the high levels of viable LAB in fermented milks are correlated with consumers’ health benefits.…”

Effect of Spirulina platensis on probiotic, nutritional, and quality properties of yogurt

“…On the last evaluation day, group B (0.5%) had the highest score. Although similar results were presented in other studies (Barkallah et al, 2017;Shazly et al, 2022), better results were obtained in the present work. As the amount of seaweed in yogurt increased, the stickiness values decreased.…”

“…WHC is related with the water retaining ability of proteins and dietary fibres in the structure of yogurt. In addition, the production of many capsular polysaccharides and exopolysaccharides by B. animalis may be another reason for this increase (Shazly et al, 2022).…”

Making Yoghurt Flavoured With Essential Oils

“…Starting from the classic yoghurt, many yoghurt varieties have been developed over time in which optional ingredients have been included such as: different strains of probiotic microorganisms (Abdelazez et al 2017, Akan et al 2022, Atallah 2016, Dimitrellou et al 2019, Douglas et al 2022, Ekinci et al 2008, Khademi et al 2022, Khalili et al 2020, Saleena et al 2022, Sarwar et al 2019, Warmi et al 2003), vitamins (Sobczak et al 2022 grains (Soltani et.al. 2017), seeds, fiber (Issar et al 2017), fruits (Abou El-Ez et al 2017, Al-Dhabi et al 2022, Buchilina & Aryana 2022Melia et al 2022, Melia et al 2022) algae (Shazly et al 2022), walnut (Baba et al 2018), honey (Rotar et al 2015, essential oils (Mishra et al 2020, Douglas et al 2017).…”