Current state, challenges and future orientations of the applications of lactic acid bacteria exopolysaccharide in foods

In the quest for a balanced diet and better health, the global shift towards nutrient-dense foods highlights the multiple roles of lactic acid bacteria exopolysaccharides (LAB-EPS) in improving food quality and health. This paper offers a comprehensive survey of LAB-EPS, focusing on their classification, biosynthesis pathways and application in the food industry, from dairy products to bakery products and meat. It highlights the impact of LAB-EPS on the texture and sensory qualities of food. Despite their promising prospects, these polysaccharides face various application challenges in the food industry. These include variability in EPS production among LAB strains, complexity in structure-function relationships, and limited understanding of their health benefits. In order to address these issues, the review identifies and suggests future research directions to optimize the production of LAB-EPS, elucidating their health benefit mechanisms, and expanding their application scope. In summary, this review aims to contribute to advance innovation and progress in the food industry by developing healthier food options and deepening the understanding of LAB-EPS in promoting human health.

Comparative analysis of the quality of buffalo milk fresh cheese processed with Moringa oleifera seed milk coagulant and calf rennet

This study aimed to evaluate the impact of buffalo milk fresh cheese produced using M. oleifera seed milk coagulant and calf rennet. No significant difference was found between composition and functional characteristics (P > 0.05). M. oleifera seed milk coagulant cheese exhibited smaller pore size, a more uniform conformation and a denser network structure compared with calf rennet cheese. Moreover, hardness, adhesiveness, and chewiness of calf rennet cheese were significantly higher compared with M. oleifera seed milk coagulant cheese (P < 0.05). The storage modulus of both cheeses was greater than the loss modulus, thus indicating viscoelastic behavior. Moreover, the elastic gel formed in M. oleifera seed milk coagulant cheese exhibited superior stability. In addition, the content of phosphoserine, glutamic acid, long-chain fatty acids, medium-chain fatty acids, saturated fatty acids, monounsaturated fatty acids, aldehydes, esters, and lactones was significantly higher in M. oleifera seed milk coagulant cheese compared with calf rennet cheese (P < 0.05). In addition, a strong correlation was found between free amino acids, free fatty acid (FFA), and volatile flavor compounds. The findings of this study provide a theoretical foundation for the application of M. oleifera seed milk coagulant as a new plant milk coagulant resource in the dairy industry.

Functional roles and engineering strategies to improve the industrial functionalities of lactic acid bacteria during food fermentation

In order to improve the flavor profiles, food security, probiotic effects and shorten the fermentation period of traditional fermented foods, lactic acid bacteria (LAB) were often considered as the ideal candidate to participate in the fermentation process. In general, LAB strains possessed the ability to develop flavor compounds via carbohydrate metabolism, protein hydrolysis and amino acid metabolism, lipid hydrolysis and fatty acid metabolism. Based on the functional properties to inhibit spoilage microbes, foodborne pathogens and fungi, those species could improve the safety properties and prolong the shelf life of fermented products. Meanwhile, influence of LAB on texture and functionality of fermented food were also involved in this review. As for the adverse effect carried by environmental challenges during fermentation process, engineering strategies based on exogenous addition, cross protection, and metabolic engineering to improve the robustness and of LAB were also discussed in this review. Besides, this review also summarized the potential strategies including microbial co-culture and metabolic engineering for improvement of fermentation performance in LAB strains. The authors hope this review could contribute to provide an understanding and insight into improving the industrial functionalities of LAB.

Metabolites, flavor profiles and ripening characteristics of Monascus-ripened cheese enhanced by Ligilactobacillus salivarius AR809 as adjunct culture

Adjunct cultures strongly determined the distinguishing sensorial and nutritional characteristics of cheeses. Metabolites, flavor profiles and ripening characteristics of Monascus-ripened cheese enhanced by the co-fermentation of Ligilactobacillus salivarius AR809 were investigated. The AR809 significantly increased the contents of soluble nitrogen, small peptides (<1200 Da), free amino acids, and casein degradation degree in the resulting cheese. Furthermore, AR809 significantly promoted the formation of methyl ketones during cheese maturation. Based on untargeted metabolomics analysis, metabolites related to fatty acids metabolism and lysine degradation were highly enriched in Monascus-rich region of cheese. AR809 was primarily engaged in amino acid metabolism, promoting the synthesis of amino acids and dipeptide. L. salivarius and Monascus co-fermentation produced more beneficial bioactive metabolites involved in amino acids and lipid metabolisms than Monascus used alone in cheese ripening. Therefore, as adjunct culture, L. salivarius AR809 exhibited tremendous potential in improving nutrition and flavor quality during cheese ripening.

Changes of physicochemical and functional properties of processed cheese made with natural cheddar and mozzarella cheeses during refrigerated storage

The present study aimed to investigate changes of physicochemical and functional properties of the processed cheeses (PCs) made with Cheddar (PC1), Mozzarella (PC2) and both of them at a ratio of 1:1 (PC3) during storage at 4 °C for 4 months. The results showed that the type of natural cheese used affected the composition of PCs with lower fat content in PC2 due to the lower fat content of Mozzarella cheese used. PC2 with lower fat content showed decreased meltability and oil leakage compared with PC1 and PC3. The stretchability of all the samples significantly (P < 0.05) decreased during storage, and PC1 showed lower stretchability. This was confirmed by increased protein hydrolysis of all the samples during the storage with a higher level of proteolysis in PC1, leading to decreased stretchability of PCs. Further low-field nuclear magnetic resonance analysis indicated more entrapped water in cheese due to moisture migration into the cheese matrix that might squeeze the fat globules to aggregate, causing more fat leakage during later stages of storage. This was evidenced by microstructural analysis showing different extents of increase in fat particle sizes and decrease in free serum in all the PC samples over the storage time. Therefore, the present study provides further understanding of the mechanism of quality change of PC during refrigerated storage as affected by proteolytic properties and composition of natural cheese used.

Determination of the effects of proteolysis-based changes by adjunct lactobacilli on the bioactivity (ACE-inhibitory and antioxidant activities) of cheese: a model cheese study

Bioactive properties, proteolysis and microbiology of model cheeses with and without adjunct lactobacilli (Lactobacillus helveticus, Lactiplantibacillus plantarum, Lactobacillus bulgaricus and L. casei) were studied during 120 days of storage at 8 or 16 °C. Bioactive properties were observed in peptide fractions (< 3 kDa, 3-10 kDa, < 10 kDa) separated using ultrafiltration membranes. Antioxidant activity of these fractions was determined by radical scavenging assays as ABTS [2, 2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)]. Angiotensin-converting enzyme-inhibitory (ACE-i) activity (% and IC50) and peptide profiles of 70% ethanol-soluble and -insoluble fractions were determined by RP-HPLC. Use of lactobacilli as an adjunct culture significantly changed the RP-HPLC peptide profiles of the cheeses; however, slight changes were observed in the patterns of urea-polyacrylamide gel electrophoresis. Fractions smaller than 3 kDa had higher ACE-i and antioxidant activities for all cheese samples. In conclusion, this study indicates that the addition of lactobacilli as an adjunct culture contributed to the formation of bioactive compounds in the model cheeses and also changed the proteolysis levels.

Effects of Nutrients on the Growth of and Free Exopolysaccharide Biosynthesis by Streptococcus thermophilus 937 in a Chemically Defined Medium

The free exopolysaccharide (f-EPS) produced by Streptococcus thermophilus is a natural texture modifier with health-promoting properties and has thus become one of the most interesting metabolites for researchers. The present work aimed to further understand the nutritional requirements for the growth of and the f-EPS production by S. thermophilus. The types and concentrations of compounds in the complete chemically defined medium were changed in turn to evaluate the effects of single nutrients on the growth of and f-EPS production by S. thermophilus 937. The results showed that cysteine, glutamine, histidine, methionine, tryptophan, tyrosine, leucine, isoleucine, and valine played an important role in maintaining the rapid and stable growth of S. thermophilus 937. S. thermophilus 937 also required calcium pantothenate, niacin, pyridoxine, riboflavin, and thiamine hydrochloride as essential nutrients for growth. Increases in the concentrations of lactose, glutamate, histidine, or isoleucine significantly increased the production of free exopolysaccharide by S. thermophilus 937, and when the lactose concentration increased to 20 g·L-1 and the concentration of the three-amino-acid combination increased to 15 mM, the f-EPS yield increased to a maximum of 35.34 μg·mL-1. This finding indicated that lactose and the 3 amino acids exert synergistic effects on the promotion of f-EPS production. In addition, lactose and the three amino acids have strain specific promoting effects on f-EPS production by S. thermophilus. This study provides a further understanding of the effects of nutrients on the biosynthesis of f-EPS by S. thermophilus.

Effects of Exopolysaccharides from Lactiplantibacillus plantarum JLAU103 on Intestinal Immune Response, Oxidative Stress, and Microbial Communities in Cyclophosphamide-Induced Immunosuppressed Mice

This study investigated the effects of the exopolysaccharide from Lactiplantibacillus plantarum JLAU103 (EPS103) on the intestinal immune response, oxidative stress, intestinal mucosal barrier, and microbial community in cyclophosphamide-induced immune-suppressed mice. The results showed that EPS103 promoted the secretion of cytokines and the generation of secretory immunoglobulin A and mucin-2 in the small intestine of mice, which might be related to the activation of the MAPK pathway. Additionally, EPS103 protected against oxidative stress by activating antioxidation enzymes and Nrf2/Keap1 pathways. It also improved the intestinal physical barrier functions via regulating the ratio of villous height to crypt depth and upregulating the expression of tight-junction proteins. Meanwhile, EPS103 promoted the generation of short-chain fatty acids (SCFAs) and modulated the constituents of gut microbiota. These results suggested that EPS103 may modulate the intestinal immunoresponse relying on the regulation of SCFA production and gut microbiota in immunosuppressed mice, resulting in the activation of systemic immunity.

Recent Advances in the Production of Exopolysaccharide (EPS) from Lactobacillus spp. and Its Application in the Food Industry: A Review

Exopolysaccharide (EPS) show remarkable properties in various food applications. In this review paper, EPS composition, structural characterization, biosynthesis pathways, and recent advancements in the context of application of EPS-producing Lactobacillus spp. in different food industries are discussed. Various chemical and physical properties of Lactobacillus EPS, such as the structural, rheological, and shelf-life enhancement of different food products, are mentioned. Moreover, EPSs play a characteristic role in starter culture techniques, yogurt production, immunomodulation, and potential prebiotics. It has been seen that the wastes of fermented and non-fermented products are used as biological food for EPS extraction. The main capabilities of probiotics are the use of EPS for technological properties such as texture and flavor enhancement, juiciness, and water holding capacities of specific food products. For these reasons, EPSs are used in functional and fermented food products to enhance the healthy activity of the human digestive system as well as for the benefit of the food industry to lower product damage and increase consumer demand. Additionally, some pseudocereals such as amaranth and quinoa that produce EPS also play an important role in improving the organoleptic properties of food-grade products. In conclusion, more attention should be given to sustainable extraction techniques of LAB EPS to enhance structural and functional use in the developmental process of food products to meet consumer preferences.

Bioactive peptides in ripened cheeses: release during technological processes and resistance to the gastrointestinal tract

Milk proteins are recognized as the main source of biologically active peptides. Casein's primary structure contains several bioactive amino acid sequences on its latent inactive form. These potential active sequences can be released during cheese manufacture and ripening, giving rise to peptides with biological activity such as antihypertensive, antidiabetic, antioxidant, immunomodulatory, and mineral-binding properties. However, the presence of biopeptides in cheese does not imply actual biological activity in vivo because these peptides can be further hydrolyzed during gastrointestinal transit. This paper reviews the recent advances in biopeptide formation in ripened cheeses production, focusing on the influence of technological parameters affecting proteolysis and the consequent release of peptides. The main discoveries in the field of cheese peptide digestion through recent in vivo and in vitro model studies are also reviewed. © 2021 Society of Chemical Industry.

Role of lactic acid bacteria in flavor development in traditional Chinese fermented foods: A review

Traditional Chinese fermented foods are favored by consumers due to their unique flavor, texture and nutritional values. A large number of microorganisms participate in the process of fermentation, especially lactic acid bacteria (LAB), which are present in almost all fermented foods and contribute to flavor development. The formation process of flavor is complex and involves the biochemical conversion of various food components. It is very important to fully understand the conversion process to direct the flavor formation in foods. A comprehensive link between the LAB community and the flavor formation in traditional Chinese fermented foods is reviewed. The main mechanisms involved in the flavor formation dominated by LAB are carbohydrate metabolism, proteolysis and amino acid catabolism, and lipolysis and fatty acid metabolism. This review highlights some useful novel approaches for flavor enhancement, including the application of functional starter cultures and metabolic engineering, which may provide significant advances toward improving the flavor of fermented foods for a promising market.

Biotechnological approaches for the production of designer cheese with improved functionality

Cheese is a product of ancient biotechnological practices, which has been revolutionized as a functional food product in many parts of the world. Bioactive compounds, such as peptides, polysaccharides, and fatty acids, have been identified in traditional cheese products, which demonstrate functional properties such as antihypertensive, antioxidant, immunomodulation, antidiabetic, and anticancer activities. Besides, cheese-making probiotic lactic acid bacteria (LAB) exert a positive impact on gut health, aiding in digestion, and improved nutrient absorption. Advancement in biotechnological research revealed the potential of metabolite production with prebiotics and bioactive functions in several strains of LAB, yeast, and filamentous fungi. The application of specific biocatalyst producing microbial strains enhances nutraceutical value, resulting in designer cheese products with multifarious health beneficial effects. This review summarizes the biotechnological approaches applied in designing cheese products with improved functional properties.

Study of the Influence of Sociodemographic and Lifestyle Factors on Consumption of Dairy Products: Preliminary Study in Portugal and Brazil

Sociodemographic characteristics, including regional variations, have been associated with different food consumption patterns. Behavioral factors and lifestyle variables may also contribute to different food dietary trends. In this way, the present study intended to investigate the consumption habits of the most relevant types of dairy products around the world and relate them to sociodemographic factors, for example, age, sex, education and country as well as with some anthropometric and behavioral aspects, for example, body mass index, satisfaction with body weight and exercise or sedentary lifestyles. One other objective of the study was to categorize the lifestyles of the participants, according to measured variables linked with hours of inactivity or exercise, in order to use these as possible differentiating variables for the consumption of dairy products. The study involved a questionnaire survey undertaken on a non-probabilistic convenience sample of participants from Portugal (PT) and Brazil (BR), and participation was voluntary and anonymous. The data analysis involved different statistical techniques: basic statistics, chi-square tests, factor analysis, cluster analysis and tree classification analysis. The results showed that semi skimmed milk is never consumed by about half of the participants (47.4% for PT and 46.7 for BR), and those numbers increase for skimmed (64.8% for PT and 50.9% for BR), chocolate flavored milk (82.6% for PT and 65.6% for BR) and enriched milks (94.8% for PT and 85.3% for BR). Cheeses are also consumed in the two countries by small numbers of people. The number of participants consuming imported cheeses in both countries was particularly low (only 4.0% consume these more than once a week in both countries), suggesting national products may be preferred. It was further observed that those who consume cheese do it seldom (once a week) or sometimes (2–3 times per week). Butter is also consumed by only about half of the adult population (43.8% for PT and 49.5% for BR), but the percentage of those who never consume butter increases for skimmed butter (66.0% for PT and 82.6% for BR) and unsalted butter (70.2% for PT and 69.1% for BR). The consumption of yogurts also follows similar low consumption patterns. The most frequently consumed yogurt types in Portugal are liquid (30.5% consume regularly) and natural yogurts (34.8% consume regularly), while in Brazil the most frequent are creamy fruit pulp yogurt (14.4% consume regularly), liquid (13.7% consume regularly) and Greek type yogurt (10.2% consume regularly). A factor analysis and a cluster analysis established groups according to lifestyles, as follows: 1—Screeners, 2—Exercisers, 3—Travelers and 4—Others. These lifestyles were found to be influential in the consumption of dairy products for all classes of dairy tested: milk, cheese, yogurt and butter. For example, the screeners were found to consume more milk, more butter, more cheese and more yogurt. Additionally, other influential factors were age, sex, education, BMI and satisfaction with body weight. Nevertheless, country was not a meaningfully discriminant variable in relation to the other variables included in the classification analysis. The results concluded that, despite some small differences in the patterns of consumption of dairy products in both countries, the levels of consumption of dairy products are extremely low, for all classes studied (milk, cheese, yogurt or butter). Additionally, it was concluded that some factors are influential on the level of consumption of dairy products, and therefore decision makers can plan their interventions according to the characteristics of the targeted segments of the population, according to lifestyle, age, sex, education, BMI and satisfaction with body weight.

Paraprobiotic obtained by ohmic heating added in whey-grape juice drink is effective to control postprandial glycemia in healthy adults

The effect of paraprobiotic Lacticaseibacillus casei 01 inactivated by ohmic heating (8 V/cm, 95 °C/7 min, 60 Hz) whey-grape juice drink at the postprandial glycemia was evaluated. In vitro hypoglycemic activity was assessed by the α-glucosidase and α-amylase inhibition, while in vivo activity was determined using 15 healthy subjects, which consumed bread + probiotic whey drink, bread + paraprobiotic whey drink, and bread alone as a control. The probiotic and paraprobiotic grape-flavored whey drinks showed similar α-glucosidase and α-amylase inhibition (51.2 vs 51.8% and 43.2 vs 44.2%, respectively). The consumption of both paraprobiotic and probiotic whey drinks increased the incremental glucose rate when compared to the control due to the presence of sugar in its composition, without changes in the other parameters evaluated (maximum glucose value, glucose incremental percentage, and peak blood glucose time), showing a reduced glycemic response. In addition, the consumption of the paraprobiotic drink maintained the maximum glucose increase similar to the control, while an increase in this parameter was observed after the consumption of the probiotic drink. Therefore, the paraprobiotic grape-flavored whey drink may be an effective alternative to replace the probiotic product in reducing the postprandial glycemia in healthy individuals.

Fermented dairy products as delivery vehicles of novel probiotic strains isolated from traditional fermented Asian foods

The screening of novel probiotic strains from various food sources including fruits, vegetables, herbs, and traditional fermented foods, have been of growing concern recently. Most of these potential probiotic lactic acid bacteria isolates were distinguished from the commercial probiotics based on multiple therapeutic effects and functionalities. Recent in vitro and in vivo investigates have also verified the usage of probiotics to lower the risk of diseases. Application of these novel strains in fermented dairy products is also an emerging trend to improve the physical and quality characteristics, functional properties, and safety of dairy products. Moreover, since dairy products are one of the highest consumed products in the globe, the dispatch channels for fermented dairy products are already established. Therefore, incorporating novel probiotic strains into fermented dairy products might be the most feasible approach for their delivery. In this context, our aim is to discuss the feasibility of dairy products as delivery vehicles for novel probiotic strains. Thus, we summarize the scientific evidence that points to a dynamic future for the production of fermented dairy-based probiotics.

Use of Exopolysaccharide-Synthesizing Lactic Acid Bacteria and Fat Replacers for Manufacturing Reduced-Fat Burrata Cheese: Microbiological Aspects and Sensory Evaluation

This study aimed to set-up a biotechnological protocol for manufacturing a reduced-fat Burrata cheese using semi-skimmed milk and reduced-fat cream, in different combinations with exopolysaccharides-synthesizing bacterial starters (Streptococcus thermophilus, E1, or Lactococcus lactis subsp. lactis and Lc. lactis subsp. cremoris, E2) and carrageenan or xanthan. Eight variants of reduced-fat cheese (fat concentration 34–51% lower than traditional full-fat Burrata cheese, used as the control) were obtained using: (i) semi-skimmed milk and reduced-fat cream alone (RC) or in combination with (ii) xanthan (RCX), (iii) carrageenan (RCC), (iv) starter E1 (RCE1), (v) starter E2 (RCE2), (vi) both starters (RCE1-2), (vii) E1 and xanthan (RCXE1), or E1 and carrageenan (RCCE1). Post-acidification occurred for the RCC, RCX, and RCE2 Burrata cheeses, due to the higher number of mesophilic cocci found in these cheeses after 16 days of storage. Overall, mesophilic and thermophilic cocci, although showing cheese variant-depending dynamics, were dominant microbial groups, flanked by Pseudomonas sp. during storage. Lactobacilli, increasing during storage, represented another dominant microbial group. The panel test gave highest scores to RCE1-2 and RCXE1 cheeses, even after 16 days of storage. The 16S-targeted metagenomic analysis revealed that a core microbiota (S. thermophilus, Streptococcus lutetiensis, Lc. lactis, Lactococcus sp., Leuconostoc lactis, Lactobacillus delbrueckii, and Pseudomonas sp.), characterized the Burrata cheeses. A consumer test, based on 105 people, showed that more than 50% of consumers did not distinguish the traditional full-fat from the RCXE1 reduced-fat Burrata cheese.

Fermented milk: The most popular probiotic food carrier

Fermented milks are extensively produced and consumed all around the world. The production of these products is an old process that was used for extending the shelf life of milk. Nowadays, numerous traditional and industrial fermented milks with various texture and aroma can be found as an important part of human diet that exhibit several health benefits. In recent years, consumers' awareness about the effect of diet on health and tendency for consuming healthful food products directed manufacturers to develop functional foods. In this context, production of probiotic food products is a common approach. Fermented milks are suitable carrier for probiotics and their production and consumption can be a beneficial way for improving health status. For development of probiotic fermented milks, probiotic viability during fermentation and storage time, their interaction with starter cultures in the product as well as their effect on sensory properties of the product should be taken into account. This chapter describes different fermented milks, probiotics used in fermented milks, process of their production and quality aspects associated with these products.

Statistical optimization of levan: Influence of the parameter on levan structure and angiotensin I-converting enzyme inhibitory

Based on Plackett-Burman design, steepest ascent method, and Box-Behnken design, statistical optimization for B. subtilis AF17 for levan production was carried out. Sucrose, tryptone and initial pH were found to be the most significant parameter (P < 0.05) for levan production. Result showed that the optimum condition was sucrose 162.5 g/L, tryptone 10 g/L, initial pH 7 and maximum yield was 7.9 ± 0.18 g/L in 72 h fermentation. Purified levan was characterized using various physicochemical techniques such as GC-MS, 1H NMR, 13C NMR spectroscopy and SEC/TDA. Based on this data, the structure of levan was independent of initial culture conditions. The biomedical potential of the isolated Bacillus subtilis A17 levan for its angiotensin-I converting enzyme (ACE) inhibition activities was exploited in vitro. Interestingly, levan possessed an important angiotensin I converting enzyme (ACE) inhibitory 81.1 ± 4.1% at 4 mg/mL. The overall, data suggested that levan presents a promising natural source of antihypertensive agents.