Impact of Different Gums on Textural and Microbial Properties of Goat Milk Yogurts during Refrigerated Storage

The Effect of High-Pressure Processing of Caprine Milk on the Production and Properties of Yoghurt

The aim of this study was to determine the suitability of HP-treated caprine milk for yoghurt production and to evaluate the effect of HP treatment on yoghurt properties. Reconstituted caprine milk was subjected to HP treatment (350 MPa/10 min/20 °C); a lactic acid starter culture (YC-X16, Chr. Hansen) was added. Milk was fermented at a temperature of 43 °C until pH 4.60. Bacterial counts, pH, color, rheological characteristics, texture, microstructure, and the sensory attributes of the yoghurt were determined after production and after seven days of storage at a temperature of 4 °C. HP treatment increased color saturation and whiteness index and induced a minor increase in milk pH. Minor differences in the acidification curve were noted. During storage, Streptococcus thermophilus counts were significantly higher in yoghurt from HP-treated than from untreated milk, whereas Lactobacillus delbruecki ssp. bulgaricus counts remained stable. A color analysis did not reveal differences between the experimental and control yoghurts. After storage, yoghurt made from HP-treated milk was characterized by thicker consistency and lower rheological stability than the control yoghurt. The micrographs of the yoghurts confirmed the differences in rheological parameters. Yoghurt produced from HP-treated caprine milk and stored for seven days received the highest scores in the sensory evaluation.

Production and application of xanthan gum-prospects in the dairy and plant-based milk food industry: a review

Xanthan gum (XG) is an important industrial microbial exopolysaccharide. It has found applications in various industries, such as pharmaceuticals, cosmetics, paints and coatings, and wastewater treatment, but especially in the food industry. The thickening and stabilizing properties of XG make it a valuable ingredient in many food products. This review presents a comprehensive overview of the various potential applications of this versatile ingredient in the food industry. Especially in the plant-based food industries due to current interest of consumers in cheaper protein sources and health purposes. However, challenges and opportunities also exist, and this review aims to identify and explore these issues in greater detail. Overall, this article represents a valuable contribution to the scientific understanding of XG and its potential applications in the food industry.

Lactic acid bacteria viability in different refrigerated food matrices: a systematic review and Meta‑analysis

The aim of this systematic review and meta-analysis was to determine which variables affect the viability of lactic acid bacteria (LAB) added to different types of refrigerated foods during the first 28 days. Scopus, ScienceDirect, PubMed and Cochrane Central Register of Reviews databases were searched from 1997 to April 2022. A total of 278 studies, which showed randomized and controlled experiments published in peer reviewed journals, were included. The viability of LAB in different moments during the storage process was synthesized as mean point estimate (MPE) via random-effects meta-analyses and the effect of multiple factors on the LAB´s viability was evaluated by multiple meta-regression. The meta-analysis showed that the decrease in LAB viability will be more abrupt the greater the initial dose. The physical structure of food may influence bacterial viability. Fruit was the type of product that most quickly lost viability. Co-culture of two or more species did not affect viability. Preservation methods had an unfavorable effect and prebiotics had a beneficial effect on bacterial viability. Viability was genus dependent. The data obtained in this study provide an overview of the factors to be taken into account for the design of new foods.

Storage stability of texture, organoleptic, and biological properties of goat milk yogurt fermented with probiotic bacteria

Introduction

Goat milk is an attractive food due to its high nutritional values, easy digestibility and hypoallergenicity, but has an undesirable "goaty" flavor.

Methods

In this study, goat yogurt was fermented with four probiotics, respectively, including Lactobacillus acidophilus (GYA), Bifidobacterium animalis (GYB), Lactobacillus casei (GYC) and Lactobacillus plantarum (GYP), and tested for texture, organoleptic, and biological properties during a 4-week storage period at the refrigerated temperature.

Results

All goat yogurt with probiotics showed an increase on titratable acidity and a corresponding downward trend on pH value. Viable counts of L. acidophilus and L. casei were above 6 log cfu/mL at the end of the storage, which met the minimum standards for viable probiotic bacteria in yogurt specified by the Food and Agriculture Organization of United Nation (FAO). The texture and organoleptic characteristics of fermented goat milk depended on the strain and the storage period. DPPH free radical scavenging rate and ferric reducing antioxidant power activity gradually increased in all goat yogurts during the storage and yogurt with probiotic bacteria showed higher values than those of GY0.

Discussion

Among all probiotic containing goat yogurts, GYC exhibited the desirable characteristics of hardness, adhesiveness, water holding capacity, antioxidant activity during the whole storage. Furthermore, the addition of L. casei effectively weakened the goaty flavor and enhanced the overall acceptability. Thus, fermented goat milk with L. casei is optional for the development of goat milk product with satisfactory texture properties, pleasant sensory quality and high bioactivity.

Iogurte simbiótico sabor cajá (Spondias Mombin L.): características físico-químicas, microbiológicas e de aceitabilidade

Resumo O objetivo do trabalho foi avaliar os parâmetros físico-químicos, microbiológicos e a aceitabilidade de iogurtes funcionais, com e sem suplementação de frutooligossacarídeos, sabor cajá. Elaborou-se quatro formulações de iogurte, sendo elas: duas com leite integral com e sem suplementação de frutooligossacarídeos e duas com leite desnatado com e sem suplementação de frutooligossacarídeos. Foram analisados os valores de pH, acidez titulável, sólidos solúveis, padrões microbiológicos de qualidade, contagem de bactérias lácticas totais e análise sensorial, na qual foram realizadas perguntas sobre frequência de consumo, conhecimento dos benefícios relacionados ao consumo de produtos lácteos fermentados, intenção de compra e índice de aceitabilidade. Quanto ao pH, a formulação elaborada com leite integral e frutooligossacarídeos apresentou diferença significativa (p < 0,05) em relação às demais formulações. Não houve diferenças significativas (p > 0,05) quanto à acidez titulável e sólidos solúveis. A contagem de bactérias lácticas totais demonstrou valores elevados que atendem aos parâmetros da legislação. As formulações apresentaram qualidade higiênico-sanitária satisfatória e foram bem aceitas pelos consumidores para todos os atributos avaliados no teste sensorial. Assim, apresentaram-se viáveis em termos sensoriais, físico-químicos e microbiológicos, com potencial aproveitamento pela população por possuírem características simbióticas benéficas à saúde.

Retention of vitamin A after goat milk processing into cheese: a nutritional strategy

The deficiency in micronutrients is a public health problem, principally in lower-middle-income countries. Vitamin A (VA) is considered a micronutrient fundamental to the maintenance and development of different tissues in the organism. Therefore, it is an essential micronutrient in the human diet. In these terms, goat milk is the leading food consumed to provide nutritional support in innumerous lower-middle-income countries. Here our work aimed to produce goat cheese studying strategies to promote the retention of VA. Our experiment design also explores the use of the salting process to evaluate the levels of VA retention. The level of VA in goat cheese was determined using LC-MS/MS analysis. Additionally, the redox status of the goat cheese in terms of lipid peroxidation and protein oxidation was determined. The texture analysis was also evaluated to verify if the redox status and salting process influence the texture profile. The results showed that the salting process during goat cheese production improves the retention of VA in goat cheese. Moreover, the salting process also is related to alterations in the status redox of the goat cheese and texture parameters. Therefore, our results show that goat cheese production can be an alternative to produced dairy derivates with recognized concentrations of VA for human nutrition.

Different Ultrasound Exposure Times Influence the Physicochemical and Microbial Quality Properties in Probiotic Goat Milk Yogurt

Despite goat milk having health benefits over cow milk, goat milk yogurt (GY) presents low consistency and viscosity, which reduces its overall acceptability by the consumer. Thus, new innovative methods can be an alternative to improve the quality of GY. Hence, this study aimed to investigate the effect of ultrasound (US) treatment with different sonication times on quality parameters of probiotic GY during refrigerated storage. US treatment was conducted at 20 KHz for 3, 6, and 9 min in yogurt. Lactobacillus bulgaricus and Lactobacillus acidophilus LA-5 were sensitive to US treatment, presenting a decrease in the yogurts stocked. This loss of viability led to reduced post-acidification due to smaller lactose metabolization in yogurt samples submitted to the US. Among tested treatments, the application of 6 min enhanced the apparent viscosity and consistency index of GY yogurts. In addition, this time also reduced tyramine and total biogenic amine (BAs) content. These findings suggest that 6 min of sonication is a promising way to improve the rheological properties and reduce the acidity and BAs content in GY. Further studies should be performed to optimize the US setting conditions to preserve the probiotic culture viability in yogurts.

Optimization of stabilized probiotic Doogh formulation by edible gums and response surface methodology: assessment of stability, viability and organoleptic attributes

In this study the effect of gelan, xanthan and quince seed gum (QSG) on stability, probiotic viability and qualitative properties of Doogh using response surface methodology was determined. Three gums were used at three levels of 0, 0.25 and 0.5%. The results showed that the effect of QSG on viscosity and serum separation was significant (P < 0.05). The effect of QSG on viability of B. bifidum was significant (P < 0.05). Sensory evaluation showed that effect of using of QSG was significant and the score of taste, odor and overall acceptance increased by increasing of concentration of QSG. At the optimum point, the stability, viscosity pH, probiotic load and overall acceptance were 92.24%, 11.852 mPa s, 3.87, 8.37 log cfu/mL and 4.42, respectively. Using of combination of gums at the optimal concentration prevented phase separation and maintained the probiotic viability of Doogh. Therefore, the optimization of formulation can be used for production of stabilized probiotic Doogh in dairy industry.