The effects of fish collagen on the proteolysis of milk proteins, ACE inhibitory activity and sensory evaluation of plain- and Allium sativum-yogurt

Technological aspects and health effects of hydrolyzed collagen and application in dairy products

With the rise of a consumer market increasingly concerned with food and healthy lifestyle habits, the search for functional products has increased in the last years. In this context, dairy products are relevant since they are already included in the consumer's diet. Furthermore, hydrolyzed collagen stands out among products with bioactive action, as it promotes the reduction of the incidence of arthritis, osteoporosis, hypertension, obesity, and premature aging and contains healing, antioxidant and antimicrobial properties. In addition to health benefits, the addition of these ingredients to dairy products can influence physical, chemical, rheological, microbiological, and sensory characteristics, such as: decreased syneresis and improved texture of fermented milks; viscosity increase in dairy beverage; increased proteolytic activity in cheeses; and increasing the viability of probiotics, without significantly altering the quality standards of the legislation. Despite the benefits described, more studies are needed to evaluate these effects in different dairy products.

Effect of Storage Time and Bacterial Strain on the Quality of Probiotic Goat's Milk Using Different Types and Doses of Collagens

Recently, increasing attention has been focused on developing new products based on goat’s milk. Consumers positively perceive fermented goat’s milk products as health-promoting due to their nutritional value, digestibility, and potential source of probiotics. This study aimed to evaluate the possibility of using different doses of collagen and collagen hydrolysate in the production of probiotic goat’s milk fermented by four monocultures: Lacticaseibacillus casei 431® Lactobacillus acidophilus LA- 5®, Lacticaseibacillus paracasei LP26, and Lacticaseibicillus rhamnosus Lr- 32®. A total of 20 experimental groups were prepared, including control groups (without additives), and due to the added probiotic (Lacticaseibacillus casei, Lactobacillus acidophilus, Lacticaseibacillus paracasei, and Lacticaseibacillus rhamnosus), various collagen doses (1.5% and 3.0%) and collagen types (hydrolysate and bovine collagen). Physicochemical, organoleptic, and microbiological characteristics were evaluated after 1 and 21 days of cold storage. The applied additives increased the acidity of the milk even before fermentation. However, milk with bovine collagen and hydrolysate had a higher pH value after fermentation than control milk. The study showed higher than 8 log cfu g−1 viability of probiotic bacteria in goat’s milk products during storage due to the proper pH, high buffering capacity, and rich nutrient content of goat’s milk. The best survival rate was shown for the L. casei strain after 21 days in milk with collagen protein hydrolysate. Moreover, collagen in milk fermented by L. rhamnosus decreased syneresis compared to its control counterpart. The addition of collagen, especially the hydrolysate, increased the gel hardness of the fermented milk. The collagen additives used in the milk, both in the form of hydrolysate and bovine collagen, caused a darkening of the color of the milk and increased the intensity of the milky-creamy and sweet taste.

Isolation, identification, and biochemical characterization of five Lacticaseibacillus strains from Oggtt: A traditional fermented and dried buttermilk

This study investigates the isolation and characterization of the main lactic acid bacteria responsible for fermentation of Oggtt, a dried fermented buttermilk. Five isolates with Gram-positive staining and negative catalase and oxidase activity were identified using phenotypic and genotypic methods, and their antagonistic, exopolysaccharides and organic acid production, proteolytic activity, and antioxidant capacity were assessed. The isolates are classified as Lacticaseibacillus paracasei Ogt_1, Lacticaseibacillus casei Ogt_2, Lacticaseibacillus paracasei Ogt_3, Lacticaseibacillus paracasei Ogt_4, and Lacticaseibacillus paracasei Ogt_5. All strains possessed high antagonistic activity against Proteus vulgaris, Staphylococcus aureus, and Escherichia coli. All strains produced high levels of lactic acid (11177.3-15404.9 μg/ml), tartaric acid (2197.8-4058.5 μg/ml), and exopolysaccharides(20.86-239.9 mg/L) and possessed high proteolytic and antioxidant activity at variable manners. Overall, this study indicates the isolation of important Lacticaseibacillus strains from Oggtt, which could be used as starter cultures for developing functional foods.

Effect of Collagen Types, Bacterial Strains and Storage Duration on the Quality of Probiotic Fermented Sheep’s Milk

Collagen has become popular in dietary supplements, beverages and sports nutrition products. Therefore, the aim of this study was to evaluate the possibility of using various doses of collagen and collagen hydrolysate to produce probiotic sheep’s milk fermented with Lactobacillus acidophilus, Lacticaseibacillus casei, Lacticaseibacillus paracasei and Lacticaseibacillus rhamnosus. The effects of storage time, type and dose of collagen, and different probiotic bacteria on the physicochemical, organoleptic and microbiological properties of fermented sheep’s milk at 1 and 21 days of refrigerated storage were investigated. The addition of collagen to sheep’s milk increased the pH value after fermentation and reduced the lactic acid contents of fermented milk compared to control samples. After fermentation, the number of probiotic bacteria cells was higher than 8 log cfu g⁻¹. In sheep’s milk fermented by L. acidophilus and L. casei, good survival of bacteria during storage was observed, and there was no effect of collagen dose on the growth and survival of both strains. The addition of collagen, both in the form of hydrolysate and bovine collagen, resulted in darkening of the color of the milk and increased the sweet taste intensity of the fermented sheep’s milk. However, the addition of hydrolysate was effective in reducing syneresis in each milk sample compared to its control counterpart.

Yogurt Fortification by the Addition of Microencapsulated Stripped Weakfish (Cynoscion guatucupa) Protein Hydrolysate

The aim of the present work was to fortify yogurt by adding a stripped weakfish (Cynoscion guatucupa) protein hydrolysate obtained with the enzyme Protamex and microencapsulated by spray drying, using maltodextrin (MD) as wall material. The effects on the physicochemical properties, syneresis, texture, viscoelasticity, antioxidant and ACE inhibitory activities of yogurt after 1 and 7 days of storage were evaluated. In addition, microbiological and sensory analyses were performed. Four yogurt formulations were prepared: control yogurt (without additives, YC), yogurt with MD (2.1%, YMD), with the free hydrolysate (1.4%, YH) and the microencapsulated hydrolysate (3.5%, YHEn). Yogurts to which free and microencapsulated hydrolysates were added presented similar characteristics, such as a slight reduction in pH and increased acidity, with a greater tendency to present a yellow color compared with the control yogurt. Moreover, they showed less syneresis, the lowest value being that of YHEn, which also showed a slight increase in cohesiveness and greater rheological stability after one week of storage. All yogurts showed high counts of the microorganisms used as starters. The hydrolysate presence in both forms resulted in yogurts with antioxidant activity and potent ACE-inhibitory activity, which were maintained after 7 days of storage. The incorporation of the hydrolysate in the microencapsulated form presented greater advantages than the direct incorporation, since encapsulation masked the fishy flavor of the hydrolysate, resulting in stable and sensorily acceptable yogurts with antioxidant and ACE inhibitory activities.

Animal by-products collagen and derived peptide, as important components of innovative sustainable food systems-a comprehensive review

In 2020, the world's food crisis and health industry ushered into a real outbreak. On one side, there were natural disasters such as the novel coronavirus (2019-nCoV), desert locusts, floods, and droughts exacerbating the world food crisis, while on the other side, the social development and changes in lifestyles prompted the health industry to gradually shift from a traditional medical model to a new pattern of prevention, treatment, and nourishment. Therefore, this article reviews animal by-products collagen and derived peptide, as important components of innovative sustainable food systems. The review also considered the preparation, identification, and characterization of animal by-product collagen and collagen peptides as well as their impacts on the food system (including food processing, packaging, preservation, and functional foods). Finally, the application and research progress of animal by-product collagen and peptide in the food system along with the future development trend were discussed. This knowledge would be of great significance for a comprehensive understanding of animal by-product collagen and collagen peptides and would encourage the use of collagen in food processing, preservation, and functional foods.

Proteolytic profile, angiotensin-I converting enzyme inhibitory activity and sensory evaluation of Codonopsis pilosula and fish collagen cheese

Four types of cheeses were prepared included plain- cheese (control), Codonopsis pilosula (CP)- cheese, plain- cheese with fish collagen (FC; control) and CP- cheese with FC. The effects of cheese samples on acidification, proteolysis of milk proteins using three methods (cadmium-ninhydrin method, O-phthaldialdehyde (OPA) assay, and electrophoresis assay), and angiotensin-converting enzyme (ACE)-inhibitory activity were investigated during 0, 2, & 4 weeks of ripening. In addition, the sensory evaluation was also investigated during 0, 2, 4, & 8 weeks of ripening. The presence of FC in CP- cheese increased the numbers of free amino acids (FAA) at 0 and 2 weeks. The addition of CP both in the presence and absence of FC affected positively (p < 0.05) on the concentrations of OPA peptide in cheese compared to their respective controls. The presence of CP and/or FC in cheese increased the degradation of milk proteins (α-, β-, & κ- caseins, β-lactoglobulin, and α-lactalbumin) compared to their respective controls during ripening periods. The highest ACE inhibitory activity was shown at 4 weeks of ripening for CP- cheese both in the absence (67.75 ± 14.15%) and the presence (78.65 ± 2.85%) of FC. In addition, 8-week-old CP-cheese in the presence and absence of fish collagen had similar organoleptic characteristics to plain-cheese. In conclusion, C. pilosula and/or fish collagen may lead to the development in the production and formulation of cheese with anti-ACE activity.

Probiotic capability of novel lactic acid bacteria isolated from worker honey bees gut microbiota

The study aimed to evaluate the probiotic and safety properties of lactic acid bacterial (LAB) strains isolated from the gut microbiota of honey bee Apis mellifera L., since this source remains a promising reservoir of microbial diversity. A total of five bacterial isolates were molecularly identified using 16S rRNA gene sequencing as Enterococcus faecalis-HBE1, Lactobacillus brevis-HBE2, Enterococcus faecalis-HBE3, Enterococcus faecalis-HBE4 and Lactobacillus casei-HBE5. Gut tolerance conditions (low pH and bile salt) were evaluated. Exopolysaccharides (EPS) production, hemolytic, antioxidant activity, resistance toward antibiotics and technological characteristics (starter activity, pH and proteolysis) were examined. The five isolates showed a high survival rate (>95%), under gastrointestinal tract conditions indicating excellent potential for application as probiotics. The isolates showed no hemolytic activities and good acidification rates in the range of pH 4.6-4.98 after incubation at 37°C for 24h. The isolates exhibited promising proteolytic activity as well as DPPH radical scavenging activity in the range of 16.52-59.39%. All the tested isolates had the capability to produce exopolysaccharides except Lactobacillus casei-HBE5. These results put forward that lactic acid bacterial strain isolated from honey bee workers can be considered as promising candidates for future applications as starter cultures and could constitute new potential probiotics for the production of functional dietary products promoting health benefits.

The effects of Lycium barbarum water extract and fish collagen on milk proteolysis and in vitro angiotensin I-converting enzyme inhibitory activity of yogurt

Plain and Lycium barbarum yogurt were made in the presence and absence of fish collagen. Yogurt samples were analyzed for acidification, milk protein proteolysis, angiotensin I-converting enzyme (ACE) inhibitory activity, and sensory evaluation during refrigerated storage for up to 21 days. The o-phthaldialdehyde peptides amount of L. barbarum yogurt both in the presence and absence of fish collagen were significantly increased during 14 days of storage. SDS-PAGE showed improvement in whey proteins degradation of L. barbarum yogurt with/without fish collagen after 3 weeks of storage. L. barbarum yogurt in absence of fish collagen was acting as a great ACE inhibitor reached up to 85% on day 7 of storage. The incorporation of L. barbarum and/or fish collagen affected to a small extent the overall sensory characteristics of yogurt. Yogurt supplemented with L. barbarum and/or fish collagen may lead to the improvement in the production and formulation of yogurt differing in their anti-ACE activity.

Short communication: Biogenic amine formation during fermentation in functional sheep milk yogurts

The present study evaluated biogenic amine (BA) content during the fermentation period in functional sheep milk yogurts. Four treatments were prepared and assessed: natural (NSY), prebiotic (PreSY), probiotic (ProSY), and synbiotic (SynSY). Biogenic amines (putrescine, cadaverine, spermidine, spermine, and tyramine), proteolysis activity, and pH were measured during each hour of fermentation. Grumixama pulp was added to all formulations as a technological strategy and potential substrate for bacteria during fermentation. The yogurt and probiotic bacteria were viable (≥7 log cfu·mL^-1) on d 0. The pH levels of the functional sheep milk yogurts had a more pronounced decrease than did the control of NSY. However, all yogurt samples underwent gradual decreases in pH until final fermentation. Proteolytic activity remained constant in all treatments during fermentation. The NSY, PreSY, ProSY, and SynSY presented the same behavior for all BA, with differences in concentration. Putrescine, cadaverine, and spermidine contents decreased, whereas spermine remained constant and tyramine increased. We conclude that fermentation of functional sheep milk yogurts can produce tyramine.

Biological activities of lactobacilli relevant to cardiovascular health in skim milk

In this study, skim milk was fermented using 14 Lactobacillus strains for 16 h at 42 °C or for 48 h at 25 °C. On conclusion of fermentation, the proteolytic, angiotensin converting enzyme-inhibitory (ACE-I), and antioxidant activities as well as the inhibition of thrombin and cholesterol micellar solubility were determined. The results revealed that Lb. paracasei B-4564 exhibited the highest ACE-I activity (68.11%) under the 42 °C for 16 h condition, while Lb. rhamnosus B-1445 demonstrated the highest ACE-I activity (92.23%) under the 25 °C for 48 h condition. Lb. paracasei B-4564 exhibited the highest inhibition rate of thrombin (42.43 and 48.10%) and cholesterol (68.60 and 87.01%) under the 42 °C for 16 h and 25 °C for 48 h conditions, receptively. Lb. rhamnosus B-442 exhibited the highest DPPH radical scavenging activity of 95.63 and 62.89% under the 42 °C for 16 h and 25 °C for 48 h conditions, receptively. Lb. rhamnosus B-1445 demonstrated the highest Fe²⁺ chelating activity and reducing power under both the tested fermentation conditions.

Angiotensin-converting enzyme inhibition and antioxidant activity of commercial dairy starter cultures

In this study, skim milk fermented with 14 commercial dairy starters were evaluated for their proteolysis ability, angiotensin I-converting enzyme (ACE)-I, and antioxidant properties. The antioxidant activity was determined using DPPH radical scavenging, chelating of Fe²⁺ ions, and reducing power assays. The results showed that the coagulation time, pH, and titratable acidity varied among the used starters and appeared to be starter dependent. Lactobacillus helveticus Lh-B02 starter had the highest proteolytic and ACE-I activity. Lactobacillus casei-01, Yo-Fast 1, YC-281, MYE 96, and YO-MIX 205 starters had the highest DPPH radical scavenging activity. Chelating of Fe²⁺ ions of the L. casei-01 starter was the highest, whereas the O-114 starter was the greatest in reducing power. Regarding the yogurt starters, Yo-Fast 1 starter exhibited h igh values o f proteolytic, ACE-I, and DPPH radical scavenging activity. A positive correlation was observed between the proteolytic and ACE-I or antioxidant activities of all starters.