In this study, the effect of stevia and inulin interactions on fermentation profile of Lactobacillus acidophilus in milk and in vitro systems was investigated. The medium were analysed for pH, cell ...density (OD600), probiotic bacterial counts, prebiotic activity score (PAS), lactic acid and short‐chain fatty acid (SCFA) content. In the second stage of the study, the potential prebiotic activity of stevia and its effect on milk fermentation characteristics as sugar substitute were evaluated in symbiotic milk system. Consequently, it was found that stevia improved the survival of L. acidophilus in in vitro and in the milk matrix and could be assigned as a potential prebiotic source and sugar replacer for the manufacture of sugar‐reduced dairy products. These results show that the in vitro‐positive prebiotic activity of stevia is closer to inulin and is related to its fermentation profile and growth parameters with high short‐chain fatty acid production. The counts of probiotic bacteria remained within the biotherapeutic level (>7 log10 cfu/mL) during 28 days of storage in stevia and inulin milk system with high viscosity index and gel characteristics.
In this study, the changes during storage in the physicochemical, textural and sensory properties of nonfat yoghurts fortified with whey proteins, namely whey protein concentrates (WPC), whey protein ...isolates and whey protein hydrolysates, were investigated. Enrichment of nonfat yoghurt with the whey protein additives (1% w/v) had a noticeable effect on pH, titratable acidity, syneresis, water‐holding capacity, protein contents and colour values on the 14th day of storage (P < 0.01). The addition of whey proteins to the yoghurt milk led to increases in the hardness, cohesiveness and elasticity values, resulting in improved textural properties. The addition of WPC improved the texture of set‐type nonfat yoghurt with greater sizes in the gel network as well as lower syneresis and higher water holding capacity. This study suggests that the addition of whey protein additives used for fortification of yoghurt gave the best textural and sensory properties that were maintained constant during the shelf life.
In this study, the effects of β‐glucan from two different cereal sources (barley and oat), as prebiotics, on the viability of Bifidobacterium animalis subsp. lactis strain Bb‐12 in probiotic set ...yoghurt and the properties of yoghurt were studied. Physicochemical properties of yoghurt samples (including pH, titratable acidity (La%), whey separation, organic acids such as lactic and acetic acid, colour (L*, a*, b*, ΔE, C*, h*) and sensorial properties) were significantly affected by the addition of barley‐ and oat‐based β‐glucan. As a result, the survival of B. animalis subsp. lactis was maintained within probiotic and therapeutic levels (>7 log cfu/g), due to the possible prebiotic effect of barley‐ and oat‐based β‐glucan, after 28 days of cold storage of the probiotic yoghurt. In conclusion, β‐glucan can be used for the development of cereal‐based functional dairy products with sufficient beneficial effects, probiotic viability and acceptable sensory characteristics.
This study investigated the effects of adding short‐chain and long‐chain inulins on the growth of Lactobacillus rhamnosus and the physicochemical and sensory properties (appearance, ...structure‐texture, odor and taste) of probiotic yogurt during cold storage. The inulin‐supplemented yogurt batches were compared with control batches of unsupplemented yogurt and L. rhamnosus‐inoculated yogurt. The inulins were incorporated at 2% w/w in the yogurt mixtures that were inoculated with L. rhamnosus and mixed cultures of Streptococcus thermophilus and L. delbrueckii ssp. bulgaricus. The contents of organic acids (lactic, citric, acetic, propionic, formic and butyric) profile were determined using high‐performance liquid chromatography. The results indicated that the viability of L. rhamnosus (6.71 log10 cfu/g) in probiotic yogurt was enhanced by the presence of short‐chain inulin (RSI). Consequently, yogurt with short‐chain inulin (RSI) received higher scores for odor, taste and overall acceptance than did yogurt containing long‐chain inulin (RLI). However, the chain lengths of the inulins did not significantly affect the consistency, product appearance or the organic acid profile.
Practical Applications
Inulin is a natural component of some fruits and vegetables and widely used in functional foods for its nutritional benefits. In addition to its health promoting properties, as a dietetic fibre and as a prebiotic ingredient inulin has technological properties, as a low‐calorie sweetener, fat substitute and texture modifier. Inulin also promotes healthy probiotic bacteria grown in the colon and enhances calcium absorption and immune functions. This study provided information on the effects of short‐chain and long‐chain inulin on the properties of probiotic yogurt containing Lactobacillus rhamnosus.
The fatty acid content and physicochemical composition of the milk obtained from 3 cattle farms at summer and winter season for different milking time were studied. Physicochemical properties varied ...due to different feeding strategies used in the observed farms. The lowest values of total fat and protein were observed in winter time with the highest fat content of morning milking. The groups of fatty acids (FAs), namely saturated (SAFA), monounsaturated (MUFA) and polyunsaturated (PUFA) were examined together with the individual acids with short and long chains. The major fatty acids of milk samples were myristic, palmitic, stearic and oleic acids. In the summer season the content of unsaturated fatty acid was quantitatively higher than the saturated fatty acid. It can be concluded that the fatty acid composition and quality of milk was significantly depended on breeding, feeding strategies, milking and cattle management practices.
Abstract In recent years, since excess adiposity is thought to be responsible for the development of chronic diseases, many ingredients have been developed for the specific purpose of fat replacement ...in functional dairy foods. Carob bean gum (CBG) is widely used in food systems to modify quality attributes and shelf-life as thickening and gelling agents. Objective of this study was to develop reduced fat (12%) and low fat (6%) yoghurt using CBG as a carbohydrate based fat replacer. The results revealed that the addition of CBG increased the textural and sensory attributes of reduced fat yoghurts. In this present study, the textural properties such as firmness, and stickiness of yoghurt samples were significantly higher in the low fat yoghurt (6%, T5) with CBG, and yellowness index was increased in low fat (6%, T3 and T5) yoghurts. The addition of CBG to reduced fat and low fat yoghurts (T4, T5) improved the sensory properties and acceptance index.
Fortifying yoghurt or dairy products with fibres and probiotic bacteria is an increasing interest to create functional foods with health benefits and improve their functionality. In this study milk ...fermented with acacia exudate gum and black carrot (Daucus carota L. ssp. sativus var. atrorubens alef) pulp components had a significantly shorter fermentation time than the others in milk fermented with Streptococcus thermophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus acidophilus and Bifidobacterium animalis subsp. lactis. Potential prebiotic addition increased the cohesiveness, index of viscosity and decreased the index of syneresis in synbiotic yoghurt samples. Sensory evaluation showed that incorporation of functional components increased satisfactory texture, and had sensory characteristics with high scores during cold storage.
In this study, the properties of the milk treated with combination of solution plasma (SP) processing and pulsed electric field (PEF) for different periods (5 and 10 min) was investigated. The ...microbiological, physicochemical, and sensory properties of the probiotic yoghurt drink (Ayran) produced from these milks were determined during storage. PEF was performed at voltage 3500 V, repetition 17,000 Hz, and pulse width 2.58 μs on the raw milk. Lactobacillus acidophilus and Bifidobacterium animalis subsp. lactis probiotic cultures were used in production with conventional yoghurt bacteria Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus. In addition to the probiotic viability, texture and sensory quality in terms of consumer preference were investigated. It was determined that the viscosity and dry matter values of the solution plasma‐treated samples were lower compared to the samples produced by heat treatment, and these values decreased further with the increase in plasma application time. It was also found that the maximum increase in L* and b* values of all samples during storage was in the samples treated with plasma for 10 min. The viability of the probiotic bacteria in probiotic Ayran samples were determined to be within the therapeutic level (>6.27 log10 cfu ml−1) with higher scores for sensorial qualifications.
Practical applications
Consumers’ expectations of more nutritious and microbiologically safe food have enabled the development of new processing technologies. Probiotic fermented milk products are products that provide health benefits in the prevention of gastrointestinal diseases, regulation of metabolism, and stimulation of the immune system. The processing of these dairy products with non‐thermal technologies provides advantages in preserving their functional properties.
Abstract In recent years, since excess adiposity is thought to be responsible for the development of chronic diseases, many ingredients have been developed for the specific purpose of fat replacement ...in functional dairy foods. Carob bean gum (CBG) is widely used in food systems to modify quality attributes and shelf-life as thickening and gelling agents. Objective of this study was to develop reduced fat (12%) and low fat (6%) yoghurt using CBG as a carbohydrate based fat replacer. The results revealed that the addition of CBG increased the textural and sensory attributes of reduced fat yoghurts. In this present study, the textural properties such as firmness, and stickiness of yoghurt samples were significantly higher in the low fat yoghurt (6%, T5) with CBG, and yellowness index was increased in low fat (6%, T3 and T5) yoghurts. The addition of CBG to reduced fat and low fat yoghurts (T4, T5) improved the sensory properties and acceptance index.
In this study single cell oil (SCO) production by Fusarium species using deproteinized whey as carbon source was investigated. The total lipid accumulated in the biomass of the fungi examined ranged ...from 0.1467 to 0.8661 mg lipid per mg wet weight. Gas chromatography analysis of the synthesized microbial lipids from the Fusarium species revealed that the major constituents were palmitic acid (C16:0), palmitoleic acid (C16:1), stearic acid (C18:0), oleic acid (C18:1) and linoleic acid (C18:2). Therefore, the whey medium was found to be effective for promotion of the accumulation of substantial amounts of lipids by Fusarium species.
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