Changes in the Physicochemical Parameters of Yoghurts with Added Whey Protein in Relation to the Starter Bacteria Strains and Storage Time

Influence of Plant Additives on Changes in the Composition of Fatty Acids, Lipid Quality Indices and Minerals of Fermented Dairy Products from Cow's Milk

The aim of this study was to assess the effect of selected plant additives on changes in the content of fatty acids, lipid quality indicators and mineral composition of yogurts produced from cow's milk. The analysis included natural yogurts and yogurts enriched with 10% of chia seeds, hulled hemp seeds, quinoa seeds and oat bran. The fatty acid composition, the content of lipid quality indicators and the content of mineral components was varied in all analyzed yogurts. The plant additives used caused significant (p ≤ 0.05) changes in their fatty acid content, i.e., a significant decrease in the content of saturated fatty acids (SFAs) and short-chain fatty acids (SCFAs), and a significant increase in the content of monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs). The plant additives used caused significant (p ≤ 0.05) changes in the content of fatty acids, i.e., a significant decrease in the content of saturated fatty acids (SFAs) and short-chain fatty acids (SCFAs), and a significant increase in the content of monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs). It was shown that additives such as chia seeds and peeled hemp seeds caused the greatest changes in the analyzed yogurts. Yogurts with these additives were characterized by a significant increase in the content of polyunsaturated fatty acids (PUFAs), including n-3 acids, and a more favorable n-6/n-3 ratio. Yogurts with these additives were also characterized by significantly (p ≤ 0.05) lower atherogenic (AI) and thrombogenic (TI) indices and a higher hypocholesterolemia-to-hypercholesterolemia ratio (H/H). The addition of peeled hemp seeds caused the greatest changes in the content of minerals. Yogurts with hemp seeds were characterized by the highest content of all measured macroelements, as well as copper, iron and zinc. In turn, the highest manganese content was determined in the yogurts with the addition of chia seeds.

Fortification of goat milk yogurts with date palm (Phoenix dactylifera L.) coproducts: Impact on their quality during cold storage

The aim of this study was to investigate the impact of different concentrations (3% and 6%) of two ingredients (paste and flour) obtained from the valorization of date fruit coproducts on the nutritional (proximate composition and mineral profile), technological (coagulation curve, pH, acidity, sugar and organic acid content and syneresis), physicochemical (color, water activity and texture), microbiological and sensory properties of goat's yogurt during 21 days of refrigerated storage. Both ingredients enhanced the growth and stability of the yogurt starter culture, thereby improving the probiotic potential of date-added yogurts. Physicochemically, the addition of date flour (at both concentrations) induces stronger modifications (texture, color and syneresis) in yogurts than the date paste. During storage, date paste reduced the syneresis and hence maintained yogurts' physical quality. Consumers preferred the yogurts with date paste (3% and 6%) rather than with date flour, because its addition led to a more brownish color and granular texture.

Yogurt, in the context of a healthy diet, for the prevention and management of diabetes and obesity: a perspective from Argentina

Diabetes is a non-communicable chronic, but preventable, disease whose occurrence is related to unhealthy lifestyles, including inadequate diet. Obesity is a risk factor for diabetes. In Argentina, 12.7% of the population is living with diabetes. In this work, we aimed at giving a perspective on the role of yogurt, as part of a healthy lifestyle, for the prevention and management of obesity and diabetes. The intake of yogurt declined in the last decade in Argentina. In the context of the global diet, the contribution of a moderate increase of yogurt consumption has the potential to improve up to 10% the nutritional density of the Argentine population's diet, given its present low diversity and wide gaps in nutritive foods. The consumption of yogurt can be beneficial in the prevention and management of obesity and T2DM. The ready availability of yogurt and its easy introduction to diverse diets suggests that educating the general public to incorporate this fermented milk as part of a healthy diet may potentially contribute to improved public health through prevention of NCDs and the costs associated with them.

Effect of freeze-dried protectants on the survival rate and fermentation performance of fermented milk's directed vat set starters

A directed vat set (DVS) starter was proposed to improve the drawbacks of liquid starters in fermented production and enhance the survival rates of B. animalis subsp. lactis BZ11, S. thermophilus Q-1, and Lactiplantibacillus plantarum LB12. The protective agent formula was optimized using the response surface method (RSM), with the survival rate as the benchmark. The best combination of cryoprotectants was determined to be BZ11: 10 % skimmed milk powder, 3 % sodium glutamate, and 15 % trehalose; LB12: 10 % skim milk powder, 5 % glutamate sodium, and 10 % trehalose; Q-1: 10 % skimmed milk powder, 3 % sodium glutamate, and 10 % trehalose. The survival rate of BZ11 significantly increased to 92.87 ± 1.25 %. The DVS fermented milk did not differ significantly from the control group regarding cholesterol removal, live cell counts and pH (p > 0.05). All DVS can be stored for at least 2500 d at -20 °C-this DVS starter for fermented milk benefits from its large-scale and automated commercial production.

Whey proteins as a functional food: Health effects, functional properties, and applications in food

Functional foods are defined as foods and ingredients that exhibit health benefits beyond their nutritional value. Research on functional foods is increasing rapidly as they may help prevent and manage some non-communicable diseases. Whey proteins are recognized as a high-quality nutrient source and known to contain some bioactive components. They are rich in essential amino acids such as cysteine, branched-chain amino acids such as leucine, valine, and isoleucine, and bioactive peptides. Whey proteins look promising as a potential functional food, given its antioxidant, anti-inflammatory, blood pressure lowering, anti-obesity, and appetite suppressing effects that is discussed in the literature. Whey proteins also show functional properties that play an essential role in food processing as an emulsifier, fat-replacer, gelling and encapsulating agent and are known to improve sensory and textural characteristics of food. This review focuses on the functional food aspects of whey proteins, associated health effects, and current food applications.

Development and properties of functional yoghurt enriched with postbiotic produced by yoghurt cultures using cheese whey and skim milk

This study aimed to examine the effects of supplementation of postbiotics derived from Streptococcus thermophilus (ST) and Lactobacillus delbrueckii subsp. bulgaricus (LB) in cheese whey (CW) and skim milk (SM) on antioxidant activity, viability of yoghurt starters, and quality parameters of low-fat yoghurt during 22 days of storage. The LB-CW (L delbrueckii ssp. bulgaricus postbiotic-containing cheese whey) sample exhibited the highest antioxidant activity, with 18.71% inhibition (p > 0.05). This sample also showed the highest water holding capacity (77.93%; p < 0.05) and a trend toward receiving the most favorable sensory attributes (p > 0.05) compared to the other samples. The LB-CW and LB-SM yoghurt samples exhibited significantly higher body and texture scores compared to the ST-SM-fortified yoghurt (p < 0.05). However, there was no significant difference in the overall acceptability of the LB-SM and ST-SM yoghurt samples across both starters (p > 0.05). Such findings highlight the potential of postbiotics as functional ingredients to enhance the nutritional and sensory aspects of yoghurt, further contributing to its appeal as a health-promoting product.

Effects of ultrasonic processing on the quality properties of fortified yogurt

This study evaluated the effect of ultrasonic processing on functional yogurts fortified with banana-resistant starch (BRS) and green papaya powder (GPP). Ultrasonication technology (80% amplitude, 8 min at 20 kHz frequency) was utilized as an alternative to conventional thermal treatment (85 °C, 30 min) to improve functional yogurts' physical and textural properties. A total of 6 set-type yogurt groups were prepared by ultrasonication (UT) and conventional treatment (CT). Based on the textural studies and correlation (Pearson's) plots, fortified and UT samples were more stiff, firm, sticky, adhesive, and viscous (least elastic) compared to the CT samples. All of the tested yogurts maintained a remarkable number of viable colony counts (≥7.23 log CFU/mL) during the storage. Ultrasonication significantly (p < 0.05) changed the L, a*, and b* color values. The ultrasonic processing reduced whey syneresis and improved the water-holding capacity in fresh and stored yogurts. Further, it retained the fatty acid profile of fortified yogurts. However, ultrasonication negatively affected, i.e., reduced the total polyphenol content and antioxidant activity of yogurts as compared to the conventionally (thermal) treated counterparts. Overall, ultrasound technology can be a potential alternative to thermal treatment for the improved quality and safety of fortified yogurts.

Properties of Yoghurt Fortified in Lactoferrin with Effect of Storage Time

The stability of fortified yoghurts during refrigerated storage is important for industry and the consumer. The aim of the study was to evaluate the nutritional value, microbiological quality, organoleptic properties, and structure of natural yoghurts made with the addition of lactoferrin during refrigerated storage. In this study, we produced natural yoghurts fortified in lactoferrin, using YC-X11 yoghurt starter culture based on Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus. Physicochemical (acidity, nutritional value and structure) as well as microbiological and organoleptic changes occurring during 28-days refrigerated storage were determined. Storage research made it possible to determine the direction of changes taking place in the products. The analysed parameters did not differ statistically significantly between the control yoghurts and those with the addition of lactoferrin. Textural and rheological studies also shown that the addition of lactoferrin did not significantly change the structure of the yoghurt. The yoghurts were characterized by high sanitary and hygienic quality during the whole refrigerated storage. Lactoferrin has a positive effect on the durability of the product.

Influence of commercial starter culture on fermentation dynamics and quality characteristics of yogurts obtained with different formulations

BACKGROUND

Four commercial starter cultures containing Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus (S1, S2, S3 and S4; S3 also contained Limosilactobacillus fermentum) were compared for fermentation, volatile flavor compounds, physicochemical parameters and microbiology, in yogurt prepared from three milk base formulations with increased protein (B1, B2 and B3).

RESULTS

The fermentation patterns differed among starters, with Yoflex Mild 1.0 (S4) and SLB95 (S2) showing the longest fermentation time, depending on the formulation. At 21 days, S. thermophilus counts were similar among starters and higher than 8.52 log CFU mL^-1 , for all yogurts. The highest counts (6.86 log CFU mL^-1 ) for L. delbrueckii subsp. bulgaricus was found for S2 yogurts made from whey protein hydrolysate (B3). Minor water-holding capacity was detected for YF-L811 (S1) yogurts. Yoflex Harmony 1.0 (S3) starter containing Lim. fermentum produced a distinctive volatile profile characterized by aldehydes with respect to yogurts prepared with S1, S2 and S4, which were characterized by ketones.

CONCLUSION

Results indicate the usefulness of carrying out studies similar to the present one to select the most appropriate process conditions depending on the desired product. © 2022 Society of Chemical Industry.

The Quality and Flavor Changes of Different Soymilk and Milk Mixtures Fermented Products during Storage

This study explored the effects of two mixed fermentation methods: one was fermenting a soymilk and milk mixture by a lactic acid bacteria fermenting agent at 0.1 g/kg and 42 °C until the acidity was 70 °T, which was set as the MFSM method, and the other was fermenting milk alone by lactic acid bacteria at 42 °C for 12 h, placing it in a 4 °C refrigerator after acidification for 24 h and then mixing it with soymilk at a 1.5:1 ratio and storing the mixture at 4 °C, which was set as the SMFSM method. The quality and flavor of the soymilk and milk mixture products were investigated on the 0th, 15th and 30th days during storage. The changes in acidity, pH, number of viable bacteria, viscosity, water-holding capacity, texture, rheological properties, sensory quality and volatile flavors were determined. The results showed that compared with the fermented soymilk and milk mixtures under the MFSM method, the samples of fermented soymilk and milk mixtures under the SMFSM method showed a significant slowdown of acidification during storage, so that the sensory quality of the products was almost unaffected by acidity on the 30th day of storage. Furthermore, the number of viable bacteria was greater than 7 log cfu/mL. The water holding capacity did not change significantly until the 30th day. There was also no whey precipitation, indicating good stability. The samples in SMFSM mode had higher aromatic contents and beans during storage than the fermented soymilk and milk mixtures in MFSM mode. The rich variety of volatile flavors and the presence of acetoin, 2-heptanone, and (E,E)-3,5-octadien-2-one throughout the storage period allowed the samples to maintain a good sensory flavor during storage.

Suitability of Goat Colostrum to Produce a Fermented Yogurt-Type Product

The aim of this study was to investigate the potential use of goat colostrum to produce a yogurt-type product as a novel functional dairy food. Four batches of fermented goat colostrum (GCY) were produced using fermented goat milk (GMY) as a reference. Physicochemical, mechanical, and microbial characteristics of cold storage fermented products were evaluated in a weekly basis for 28 days. Sensory analysis was applied to detect potential differences between products and to evaluate the acceptance of GCY by consumers. Results indicate that colostrum showed higher coagulation times than goat milk (480 vs. 350 min to reach pH 4.6). In general, GCY showed a higher protein and fat content and similar features than GMY for most quality parameters, which were highly stable along time. Sensory evaluation led to significant differences between products related to their color and taste. The consumer acceptance test, using a 5 point-Likert scale, showed an overall acceptance of 3.90 ± 0.79 for GCY, with aroma and consistency being the sensory attributes having highest ratings (4.30 ± 0.80 and 4.20 ± 0.96, respectively). Therefore, fermenting goat colostrum with yogurt specific starters could be an interesting alternative to make use of surplus colostrum on farms, allowing for the diversification of commercial goat milk products with potential health benefits for the consumer.

An insight into the health beneficial of probiotics dairy products: a critical review

Probiotic dairy products satisfy people's pursuit of health, and are widely favored because of their easy absorption, high nutritional value, and various health benefits. However, its effectiveness and safety are still controversial. This proposal aims to analyze the effect of probiotics on the quality characteristics of dairy products, clarify a series of physiological functions of probiotic dairy products and critically evaluate the effectiveness and safety of probiotic dairy products. Also, dairy products containing inactivated microorganisms were compared with probiotic products. The addition of probiotics enables dairy products to obtain unique quality characteristics, and probiotic dairy products have better health-promoting effects. This review will promote the further development of probiotic dairy products, provide directions for the research and development of probiotic-related products, and help guide the general public to choose and purchase probiotic fermentation products.

The Concept of Postbiotics

The scientific community has proposed terms such as non-viable probiotics, paraprobiotics, ghostbiotics, heat-inactivated probiotics or, most commonly, postbiotics, to refer to inanimate microorganisms and/or their components that confer health benefits. This article addresses the various characteristics of different definitions of ‘postbiotics’ that have emerged over past years. In 2021, the International Scientific Association for Probiotics and Prebiotics (ISAPP) defined a postbiotic as “a preparation of inanimate microorganisms and/or their components that confers a health benefit on the host”. This definition of postbiotic requires that the whole or components of inactivated microbes be present, with or without metabolic end products. The definition proposed by ISAPP is comprehensive enough to allow the development of postbiotics from different microorganisms, to be applied in different body sites, encouraging innovation in a promising area for any regulatory category and for companion or production animals, and plant or human health. From a technological perspective, probiotic products may contain inanimate microorganisms, which have the potential to impart a health benefit. However, their contribution to health in most cases has not been established, even if at least one probiotic has been shown to confer the same health benefit by live or inanimate cells.

Fatty Acid Profile, Conjugated Linoleic Acid Content, and Lipid Quality Indices in Selected Yogurts Available on the Polish Market

The aim of the present study was to determine the fatty acid composition, the content of cis9trans11 C18:2 acid (CLA), and lipid quality indices in yogurts made of cow's milk, available on the Polish market. The test material consisted of: natural yogurts, natural yogurts with additives (muesli, cereal grains), bio yogurts, bio yogurts with additives (millet groats, quinoa, chestnuts), probiotic yogurts, and eco yogurts. All the products were bought in the period from May to June 2021. The conducted research showed that the analyzed yoghurts were characterized by a varying content of fatty acid groups, different values of the calculated lipid quality indices, as well as a different content of conjugated linoleic acid cis9trans11 C18: 2 (CLA). Natural yogurts with additives had the highest content of polyunsaturated fatty acids (PUFAs) and n-3 PUFAs. Natural and bio yogurts with additives had a higher content of n-6 PUF than the other analyzed yogurts. The n-6/n-3 ratio was lower in bio yogurts and eco yogurts. Natural yogurts with additives featured the lowest index of atherogenicity (AI) and index of thrombogenicity (TI) and the highest hypocholesterolemic/hypercholesterolemic ratio (H/H). The fat extracted from the bio yogurts had the highest (0.90% of total fatty acids) mean content of cis9trans11 C18:2 (CLA). In fat of the other analyzed yogurts, mean CLA content in total content of fatty acids varied from 0.48% in natural yogurts with additives to 0.81% in bio yogurts with additives.

Chemical composition, quality attributes and antioxidant activity of stirred-type yogurt enriched with Melastoma dodecandrum Lour fruit powder

Incorporation of Melastoma dodecandrum Lour fruit powder as a promising functional ingredient for stirred-type yogurt (STY) improved physicochemical properties, polyphenol contents, antioxidant activity, microstructure, and texture of STY.

Functionality and Palatability of Yogurt Produced Using Beetroot Pomace Flour Granulated with Lactic Acid Bacteria

Following the idea of sustainability in food production, a yogurt premix based on beetroot (Beta vulgaris) pomace flour (BPF) was developed. BPF was granulated with lactose solution containing lactic acid bacteria (LAB) by a fluidized bed. Particle size increased ~30%. A decrease in Carr Index from 21.5 to 14.98 and Hausner ratio from 1.27 to 1.18 confirmed improved flowability of granulated BPF, whereas a decrease in water activity implied better storability. Yogurts were produced weekly from neat starters and granulated BPF (3% w/w) that were stored for up to one month (4 °C). High viability of Streptococcus thermophilus was observed. Less pronounced syneresis, higher inhibition of colon cancer cell viability (13.0-24.5%), and anti-Escherichia activity were ascribed to BPF yogurts or their supernatants (i.e., extracted whey). Acceptable palatability for humans and dogs was demonstrated. A survey revealed positive consumers' attitudes toward the granulated BPF as a premix for yogurts amended to humans and dogs. For the first time, BPF granulated with LAB was used as a premix for a fermented beverage. An initial step in the conceptualization of a novel DIY (do it yourself) formula for obtaining a fresh yogurt fortified with natural dietary fiber and antioxidants has been accomplished.

Effect of Sea Buckthorn (Hippophae rhamnoides L.) Mousse on Properties of Probiotic Yoghurt

The stability of the physico-chemical and sensory characteristics of yoghurts during refrigerated storage is important for industry and the consumer. The aim of the study was to evaluate the nutritional value, microbiological quality, sensory properties, and structure of natural probiotic yoghurts made with the addition of sea buckthorn fruit mousse during refrigerated storage. In this study, we produced natural, probiotic organic yoghurts with the addition of superfoods, i.e., sea buckthorn (Hippophae rhamnoides L.) fruit mousse, using ABT-1 probiotic yoghurt starter culture based on Lactobacillus acidophilus LA-5, Bifidobacterium lactis BB-12, and Streptococcus thermophilus. Physico-chemical (acidity, nutritional value, and structure) as well as microbiological and sensory changes occurring during 21-day refrigerated storage were determined. The yoghurts were characterized by high sanitary and hygienic quality during the whole refrigerated storage. Fourier-Transform Infrared (FTIR) spectra were also used in the analyses of the obtained yoghurt samples. The applied yoghurt additive was visible at the spectral level as an increase in the intensity of the characteristic bands for vibrations related to protein, fat, and polysaccharide structures. Sea buckthorn can be used as a modern and unconventional addition to yoghurts with health-promoting properties. Micrographic studies have shown that the addition of sea buckthorn mousse significantly changes the microstructure of the yoghurt. The structure of sea buckthorn to yoghurt seems to be more susceptible to the influence of damaging factors, which is also confirmed by the FTIR test conducted during the storage.