Adjunct Starter Cultures Research Articles

Development of a functional Greek sheep yogurt incorporating a probiotic Lacticaseibacillus rhamnosus wild-type strain as adjunct starter culture

Greek yogurt is a fermented dairy product of high nutritional value that can be used as a matrix for the delivery of probiotics. The aim of this study was to develop a new probiotic Greek sheep yogurt with upgraded quality and functional characteristics. To do this, yogurt was manufactured by fermenting pasteurized milk with the commercial starter culture (Streptococcus thermophilus (ST), Lactobacillus bulgaricus (LB)) together with a probiotic Lacticaseibacillus rhamnosus (LR) wild-type strain (probiotic yogurt; PY). As a control, yogurt manufactured with only the starter culture (ST, LB) was used (conventional yogurt; CY) The survival of all three lactic acid bacteria (LAB) species (ST, LB, and LR) was monitored throughout the products’ shelf life (storage at 4 °C for 25 days), and also following exposure to a static in vitro digestion model (SIVDM). The population dynamics of total aerobic plate count (APC), Enterobacteriaceae, yeasts and molds grown in both yogurts were also determined. The total antioxidant activity (AA) of yogurts was comparatively determined using in parallel two different assays, whereas the Folin-Ciocalteu assay was used to determine their total phenolic content (TPC). At each sampling day, yogurts were also evaluated for their pH, titratable acidity (TA) and main sensory characteristics. The population of probiotic LR remained stable during the shelf life (and above 108 CFU/g). Yogurt starters (ST, LB) were not detected following SIVDM, whereas LR (in PY) presented a reduction of about only one log. The AA and TPC of PY were found significantly higher than that of CY (P < 0.05). At the end of storage (25th day), neither pH nor TA differed significantly between the two yogurt types, while no fungal growth was observed in the PY. Consumer sensory analysis did not reveal important differences between the two yogurt types during their shelf life. To sum up, the novel yogurt was able to deliver to consumers a high number of probiotic cells (>108 CFU/g), presented increased antioxidant power, had an expanded shelf life, and maintained its good sensory attributes.

Bacteriocinogenic Lacticaseibacillus paracasei strains from Inner Mongolian fermented milk efficiently control pathogenic bacteria in model cheddar-like cheese

Bacteriocins produced by lactic acid bacteria (LAB) consist of a wide range of antimicrobial proteins or peptides which can be used as bio-preservatives to control food-borne pathogens. In this study, bacteriocinogenic LAB strains were isolated from fermented milk in Inner Mongolia, China. These strains exhibited high antimicrobial activity and were identified as Lacticaseibacillus paracasei. The sensitivity of their antimicrobial activity to protease K implies the possible existence of bacteriocins within the culture. Selected L. paracasei strains were subjected to whole genome sequencing and the bacteriocin biosynthetic gene clusters were identified in-silico. To further verify the antimicrobial properties of the isolated strains in controlling food pathogens in model Cheddar-like cheese, they were used as adjunct starter cultures in cheese contaminated with Bacillus cereus and Listeria monocytogenes. The results showed that each of the five strains carries a minimum of three bacteriocins biosynthetic gene clusters. All L. paracasei strains exhibited the ability to inhibit B. cereus and L. monocytogenes and caused a significant log reduction of pathogens during cheese ripening. Additionally, the isolated strains improved cheese texture and flavor to varying degrees. In conclusion, the indigenious L. paracasei present in milk could play an important role in pathogen control and the quality improvement of Cheddar-like cheeses.

Lactic acid bacteria as an adjunct starter culture in the development of metabiotic functional turmeric (Curcuma longa Linn.) beverage.

Turmeric (Curcuma longa) is a highly nutritious rhizomatous herbaceous plant with remarkable chemical composition and biologically active compounds. This study aimed to evaluate the turmeric, ginger and lemon blend as a fermentable substrate by lactic acid bacteria to develop a fermented nondairy beverage. Results showed that turmeric blend (turmeric 2% w/v, ginger 1.5% v/v, 5% v/v) was an excellent matrix for lactic acid bacteria growth and fermentation dramatically increased total phenolic, flavonoid content and antioxidants capacities impacting the color and sensory properties. Moreover, the formulated fermented turmeric blend was stable for more than 90 days at 4 °C with a healthy bacterial population and nutraceutical stability. Turmeric beverage also inhibited the growth of Caco-2 and MOLT 4 cancerous cell lines in a dosage and time-reliant manner. This way, lactic acid fermentation can be considered as an appropriate tool for developing turmeric based novel bio-intervention with enhanced bioactivity and antagonistic efficacy against recurring food-borne pathogen in this post-antibiotic era.

Development of a novel functional yogurt rich in lycopene by Bacillus subtilis

Functional lycopene-rich yogurt displays attractive nutritious and health-promoting benefits among existing functional dairy products, owing to supplement with lycopene which could enhance immunity, prevent cancer, and cardiovascular diseases. Due to poor stability and fat-solubility of lycopene, its incorporation into yogurt is challengeable. In this study, carotenoid genes for lycopene synthesis were co-introduced into probiotic Bacillus subtilis for efficient lycopene production. Further engineered B. subtilis was applied as adjunct starter culture for achieving lycopene-rich yogurt. Developed yogurt exhibited desirable physiochemical characteristics compared with plain yogurt. Moreover, lycopene-rich yogurt was endowed with significantly high antioxidant capacity. More importantly, this functionalized yogurt had attractive sensorial attributes for quality-assured food to facilitate consumer acceptance. As the first report of fortifying yogurt of lycopene using B. subtilis with improved functional properties, this study offers a new and facile clue to enrich bioactive lycopene and probiotic B. subtilis in yogurt for healthy and nutritional food development.

Effects of Bifidobacterium longum CCFM5871 as an adjunct starter culture on the production of fermented milk

Bifidobacterium has been widely studied for its probiotic properties. In our previous study, Bifidobacterium longum CCFM5871 (CCFM5871) showed potential to relieve inflammation and constipation. In current study, we investigated the application of CCFM5871 as an adjunct starter culture for the production of fermented milk. First, genome analysis indicated that CCFM5871 possess various carbohydrate metabolic pathways, including the Leloir pathway of galactose metabolism and galactose related genes GH2 and GH27. Comparative genomic analysis shows that similar functional gene were detected in other bifidobacteria strains applied in dairy fermentation. Then the sugar metabolism phenotype experiment verified the result of genomic analysis. Subsequently, we evaluated the effects of CCFM5871 supplementation on the production and storage of fermented milk by monitoring changes in multiple parameters over 14 days of storage at 4 °C, including pH, titratable acidity, physical properties, volatile flavor compounds, and sensory quality. The bacterial level was significantly higher at the fermentation termination than the fermentation initiation, indicating that CCFM5871 can be regarded as a candidate for adjunct start culture. Compared to the control group, supplementation with CCFM5871 increased acidification and solidification of fermented milk. Moreover, we revealed that there was no other significant difference between the yogurt fermented with CCFM5871 and the yogurt with culture only in flavor and taste. In summary, our results identified that CCFM5871 may be an appropriate co-culture for fermented milk, and the genomic analysis may be instructive for future to filter the culture in fermented milk.

Inhibition of Listeria monocytogenes in Fresh Cheese Using a Bacteriocin-Producing Lactococcus lactis CAU2013 Strain.

In recent years, biocontrol of foodborne pathogens has become a concern in the food industry, owing to safety issues. Listeria monocytogenes is one of the foodborne pathogens that causes listeriosis. The major concern in the control of L. monocytogenes is its viability as it can survive in a wide range of environments. The purpose of this study was to isolate lactic acid bacteria with antimicrobial activity, evaluate their applicability as a cheese starter, and evaluate their inhibitory effects on L. monocytogenes. Lactococcus lactis strain with antibacterial activity was isolated from raw milk. The isolated strain was a low acidifier, making it a suitable candidate as an adjunct starter culture. The commercial starter culture TCC-3 was used as a primary starter in this study. Fresh cheese was produced using TCC-3 and L. lactis CAU2013 at a laboratory scale. Growth of L. monocytogenes (5 Log CFU/g) in the cheese inoculated with it was monitored during the storage at 4°C and 10°C for 5 days. The count of L. monocytogenes was 1 Log unit lower in the cheese produced using the lactic acid bacteria strain compared to that in the cheese produced using the commercial starter. The use of bacteriocin-producing lactic acid bacteria as a starter culture efficiently inhibited the growth of L. monocytogenes. Therefore, L. lactis can be used as a protective adjunct starter culture for cheese production and can improve the safety of the product leading to an increase in its shelf-life.

Lactic acid bacteria as an adjunct starter culture in the development of metabiotic functional black pearl grapes beverage

Black pearl Grapes are highly nutritious and one of the richest sources of polyphenols, but due to being delicate with very high loss at harvest and during distribution, is not consumed adequately. This study intended to develop functional lactic acid starter culture based fermented grapes beverage, in order to improve the quality and stability of this low pH fruit and to develop a fermented non-dairy beverage. Results showed that grapes blend was an excellent matrix for LAB growth with more than 9.38 log10 CFUml-1 of viability at the end of fermentation. LAB fermentation affectedly enhanced the total polyphenols and flavonoids content. Likewise, antioxidants capacities based on DPPH and FRAP activity were considerably increased correlating with each other, impacting the color and sensory properties of the grapes beverage. This way, the lactic acid fermentation can be considered as an appropriate tool for developing black pearl grapes based novel bio-intervention with enhanced antioxidants, polyphenols and flavonoids with anti-proliferative activity and antagonistic efficacy against recurring food borne pathogen in this post-antibiotic era.

Effects of Bacillus coagulans GBI-30, 6086 as an adjunct starter culture on the production of yogurt

The effects of Bacillus coagulans GBI-30, 6086 (BC30) as supplementation on yogurt fermentation and storage were investigated in this study. Over 14 d of storage at 4 °C, we monitored changes in multiple parameters, including pH, titratable acidity, bacterial level, texture profiles, volatile flavor compounds, and sensory quality. BC30 supplementation improved fermented milk acidification and proteolysis. The bacterial level was significantly higher at the fermentation termination (5.59 log CFU/mL) than the fermentation initiation (6.86 log CFU/mL) (P < 0.05), indicating that BC30 own the potential to serve as an adjunct start culture. During the storage period, a high bacterial level of BC30 was detected. With prolonged storage, the yogurt samples supplemented with BC30 showed a decrease in firmness and an increase in viscosity. Furthermore, 12 discriminatory volatiles of BC30 fermented yogurt were detected during storage. Notably, the contents of some important diketones (2,3-butanedione and 3-hydroxy-2-butanone) increased continuously during storage, peaking at 14 d. The BC30-supplemented fermented milk had similar human sensory scores to the control group. Comparative genomic analysis between BC30 and B. coagulans-70 indicated that both these two strains showed the potentially to survive in the dairy environment. Our results will be of interest to the dairy industry to develop novel functional dairy products.

Effects of Bifidobacterium Longum Ccfm5871 as an Adjunct Starter Culture on the Production of Fermented Milk

Effects of Bifidobacterium Longum Ccfm5871 as an Adjunct Starter Culture on the Production of Fermented Milk

Impact of Different Types of Exopolysaccharide-Producing Adjunct Starter Cultures on Enhancement of Karish Cheese Properties

Karish cheese is acid coagulated traditional Egyptian cheese and it exhibited undesirable textural characteristics. Therefore, Exopolysaccharide (EPS) producing Lactobacillus (Lb.) paracasei S12, Lb. paracasei S8, Enterococcus (Ent.) durans S27 and Ent. hirae S9 were used as adjunct cultures in manufacturing of Karish cheese. The effect of these adjunct cultures on the moisture content, fat, pH, yield, proteolytic activity, texture profile and over all sensory acceptance were studied. The moisture content in Karish cheese was significantly increased when EPS starter cultures were added particularly with two strains of enterococci. No significant changes were found in fat content and pH values between different Karish cheese treatments. The range of Fat/dry matter was between 3.57 to 5.67%. Cheese yield increased by 1.5 to 4% as a result of adding EPS producing cultures. Also, values of texture profile of different Karish cheese treatments were enhanced. Karish cheese manufactured with Ent. durans S27 had the highest proteolytic activity and had the lowest overall sensory acceptance score. The results of this study indicate that Lb. paracasei S12 and S8 and Ent. hirae S9 are recommended as adjunct cultures for manufacturing of Karish cheese.

Genomic analysis of B. coagulans ATCC 7050T reveals its adaption to fermented milk as an adjunct starter culture for yogurt

In this study, B. coagulans ATCC 7050T was used as a probiotic supplement. Genome analysis showed that carbohydrate metabolism pathways related to lactose and galactose were determined in B. coagulans ATCC 7050T, which indicated this strain has adaptability to fermented milk. The sugar metabolism phenotype analysis of this strain was also studied. The results showed that the strain had application potential in the development of dairy industry. Subsequently, the quality of yogurt samples fermented by commercial starter culture and B. coagulans ATCC 7050T in three proportions (1:1, 1:5, 1:10) was evaluated. Compared to the control group, the addition of B. coagulans ATCC 7050T enhanced fermented milk acidification and proteolysis. However, the post-acidification differences were more obvious with prolonged storage and the use of a larger inoculum of B. coagulans ATCC 7050T. Next, the physical properties of yogurt samples, including water holding capacity, hardness, consistency, cohesiveness, viscosity, and volatile compound content, were determined during the storage period. Compared to other groups, the yogurt samples in the YO-MIX 300 + B. coagulans ATCC 7050T (1:1) group were the most similar to the control group, suggesting the recommended proportion between starter culture and B. coagulans ATCC 7050T was 1:1 (viable bacteria).

Effect of adjunct starter culture on the quality of reduced fat, white, brined goat cheese: part I. Assessment of chemical composition, proteolysis, lipolysis, texture and sensory attributes

Effect of adjunct starter culture on the quality of reduced fat, white, brined goat cheese: part I. Assessment of chemical composition, proteolysis, lipolysis, texture and sensory attributes

Effects of Bacillus coagulans as an adjunct starter culture on yogurt quality and storage

Bacillus coagulans has been widely studied for its probiotic properties. Therefore, identifying a strain that can be used as an adjunct starter culture for yogurt production would have commercial value. In this study, 30 B. coagulans strains were isolated from vegetable samples from 11 provinces or autonomous regions in China, and their pan-genomic and phylogenetic characteristics were analyzed. Phylogenetic analysis categorized 30 strains into 4 different subphylotypes, including subtype I (11 isolates), subtype II (7 isolates), subtype III (11 isolates), and subtype IV (1 isolate). Four B. coagulans strains (B. coagulans-70, B. coagulans-78, B. coagulans-79, and B. coagulans-100) were randomly selected from each subphylotype of the phylogenetic tree as adjunct starter cultures. Compared with the other tested strains, B. coagulans-70 showed the highest count in yogurt at the end of the manufacturing period. Comparative genome analysis indicated that the different bacterial levels of B. coagulans strains in yogurt may be associated with the abundance of genes related to carbohydrate transport and metabolism (e.g., sucrose utilization). Finally, differences in texture and volatile flavor compound profiles were observed between the yogurt samples. Compared with the other groups, the addition of B. coagulans-70 exerted a positive effect on the appearance and texture of yogurt products. Volatile analysis showed increased quantities of 2-heptanone, 2-nonanone, amyl alcohol, and 2-hydroxy-3-pentanone in the B. coagulans-70 group compared with control yogurts. These results above combined with the results of a sensory evaluation indicated that B. coagulans-70 is the most suitable strain for further use in functional dairy product development.

Technological and enzymatic characterization of the yeasts isolated from natural fermentation media of Gemlik olives.

To determine the technological and enzymatic characteristics of 54 yeast strains belonging to 16 species previously isolated from natural fermentation media of Gemlik olives. The distinguishing feature of these strains, according to their selective technological and enzymatic properties using principal component analysis (PCA), was also intended. The technological properties of yeast strains, growth characteristics at different temperatures, pH and salt concentrations were examined. Besides, yeast strains' abilities to use oleuropein as a sole carbon source, to assimilate citric acid and to produce H2 S were examined and their catalase, pectolytic, proteolytic and killer activities were also tested. All strains could grow between 15 and 28°C which are favourable temperatures for natural olive fermentation and they were able to tolerate high salt concentration and low pH in the brine of natural fermentation media. As a result of enzymatic characterization with API-ZYM test system, all strains have esterase activity, which is an important feature for developing table olive aroma. In this research, β-glucosidase activity, which contributes to removing bitterness out of olives, was one of the main distinguishing features of yeast strains. Several strains of Candida hellenica, Pichia anomala and Candida pelliculosa species had β-glucosidase activity. PCA tested yeasts and several strains belonging to C. hellenica (AF84-1), P. anomala (BF1-1, BF46-2) and C. pelliculosa (BF46-3, BF143-2) species have promising technological and enzymatic properties for natural table olive production. Five promising strains belonging to C. hellenica, P. anomala and C. pelliculosa species may be suitable adjunct starter cultures with lactic acid bacteria in natural fermentation media of table olive. This study has been the first contribution to the enzymatic and technological characterization of yeasts isolated from Gemlik olives in Turkey. Some strains could be proposed as a promising adjunct culture in the production of table olives.

GABA-Producing Natural Dairy Isolate From Artisanal Zlatar Cheese Attenuates Gut Inflammation and Strengthens Gut Epithelial Barrier in vitro.

Probiotic bacteria are recognized for their health-promoting properties, including maintenance of gut epithelial integrity and host immune system homeostasis. Taking into account the beneficial health-promoting effects of GABA, the presence of the gadB gene, encoding glutamate decarboxylase that converts L-glutamate to GABA, was analyzed in Lactic Acid Bacteria (LAB) natural isolates from Zlatar cheese. The results revealed that 52% of tested Lactobacillus spp. and 8% of Lactococcus spp. isolates harbor the gadB gene. Qualitative and quantitative analysis of GABA production performed by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC) revealed the highest GABA production by Lactobacillus brevis BGZLS10-17. Since high GABA-producing LAB natural isolates are the most valuable source of naturally produced GABA, the probiotic properties of BGZLS10-17 were characterized. This study demonstrated high adhesion of BGZLS10-17 strain to Caco-2 cells and the ability to decrease the adhesion of Escherichia coli ATCC25922 and Salmonella enterica C29039. Treatment of differentiated Caco-2 cells monolayer with BGZLS10-17 supernatant containing GABA alleviated inflammation (production of IL-8) caused by IL-1β and significantly stimulated the expression of tight junction proteins (zonulin, occludin, and claudin 4), as well as the expression of TGF-β cytokine leading to the conclusion that immunosuppression and strengthening the tight junctions can have significant role in the maintenance of intestinal epithelial barrier integrity. Taken together the results obtained in this study support the idea that using of GABA producing BGZLS10-17 probiotic strain could be a good strategy to modulate immunological response in various inflammatory diseases, and at the same time, it could be a good candidate for adjunct starter culture for production of GABA-enriched dairy foods and beverages offering new perspectives in designing the novel functional foods.

Erratum to “Effects of applying Lactobacillus helveticus H9 as adjunct starter culture in yogurt fermentation and storage” (J. Dairy Sci. 102:223–235)

Erratum to “Effects of applying Lactobacillus helveticus H9 as adjunct starter culture in yogurt fermentation and storage” (J. Dairy Sci. 102:223–235)

Effects of applying Lactobacillus helveticus H9 as adjunct starter culture in yogurt fermentation and storage

Lactobacillus helveticus H9 is a probiotic bacterium originating from traditional Tibetan kurut. It has high angiotensin-converting enzyme-inhibitory (ACEI) and antihypertensive activities. We aimed to evaluate the effects of L. helveticus H9 supplementation in yogurt fermentation and storage. We monitored changes of multiple parameters over 28 d of storage at 4°C; namely, pH, titratable acidity, free amino groups, ACEI activity, physical properties, volatile flavor compounds, and sensory quality. Supplementation of L. helveticus H9 enhanced fermented milk acidification and proteolysis, resulting in a shorter fermentation time. The H9 treatment significantly increased the ACEI activity of the fermented milks. Fifteen key volatile flavors were detected by solid-phase microextraction-gas chromatography-mass spectrometry across all samples. More alcohols, aldehydes, and nitrogenous compounds, especially acetoin and benzaldehyde, were detected in the H9-supplemented fermented milks. The human sensory scores for flavor and texture, but not appearance, were lower for the H9-supplemented fermented milks, particularly beyond 2 wk of cold storage. Our results will be of interest to the dairy industry for developing novel functional dairy products.

Characterization of the Microbial Diversity and Chemical Composition of Gouda Cheese Made by Potential Probiotic Strains as an Adjunct Starter Culture.

This study characterized the microbial diversity and chemical properties of Gouda cheese made by probiotics during ripening periods. Lactobacillus plantarum H4 (H4) and Lactobacillus fermentum H9 (H9), which demonstrate probiotic properties and bioactivity, were used as adjunct starter cultures. Gouda cheese made with H4 (GCP1) and H9 (GCP2) demonstrated the highest production of formic acid and propionic acid, respectively. Moreover, the bacterial diversity, including richness and evenness of nonstarter lactic acid bacteria (NSLAB), increased in probiotic cheeses. Specifically, Lactobacillus, Leuconostoc, and Streptococcaceae were present at higher concentrations in probiotic cheeses than in control Gouda cheese (GCC). The proportion of H4 in GCP1 increased and culminated at 1.76%, whereas H9 in GCP2 decreased during ripening. Peptide profiles were altered by the addition of probiotics and included various bioactive peptides. In particular, three peptide fragments are newly detected. Therefore, Gouda cheese could be used as an effective probiotic carrier for H4 and H9.

Changes during ripening of reduced-fat Dutch-type cheeses produced with low temperature and long time (LTLT) heat-treated adjunct starter culture

Reduced-fat Dutch-type cheeses with low temperature and long time (LTLT) heat-treated adjunct starter cultures produced in the dairy industry were analyzed for basic chemical, proteolytic, microbiological, texture and organoleptic characteristics. Cheeses were produced with 1.5% addition of XT-312 starter heat-treated at 65 °C for 10 or 30 min. Particular analyses were carried out after 3, 6, 9 and 12 weeks of cheeses ripening. The use of the adjunct XT-312 starter heat-treated at both 10 and 30 min caused acceleration of the ripening process compared to control cheeses. The cheeses were determined for the content of nitrogen soluble at pH 4.6, TCA soluble nitrogen and ammonia nitrogen. The long time of the heat treatment of the additional starter turned out to be effective in improving textural and organoleptic characteristics of the analyzed reduced-fat cheeses.

Phage-Host Interactions of Cheese-Making Lactic Acid Bacteria

Cheese production is a global biotechnological practice that is reliant on robust and technologically appropriate starter and adjunct starter cultures to acidify the milk and impart particular flavor and textural properties to specific cheeses. To this end, lactic acid bacteria, including Lactococcus lactis, Streptococcus thermophilus, and Lactobacillus and Leuconostoc spp., are routinely employed. However, these bacteria are susceptible to infection by (bacterio)phages. Over the past decade in particular, significant advances have been achieved in defining the receptor molecules presented by lactococcal host bacteria and in the structural analysis of corresponding phage-encoded receptor-binding proteins. These lactococcal model systems are expanding toward understanding phage-host interactions of other LAB species. Ultimately, such scientific efforts will uncover the mechanistic (dis)similarities among these phages and define how these phages recognize and infect their hosts. This review presents the current status of the LAB-phage interactome, highlighting the most recent and significant developments in this active research field.