Common Starter Culture Research Articles

Fermentation of Rice, Oat, and Wheat Flour by Pure Cultures of Common Starter Lactic Acid Bacteria: Growth Dynamics, Sensory Evaluation, and Functional Properties.

Recent consumer demand for non-dairy alternatives has forced many manufacturers to turn their attention to cereal-based non-alcoholic fermented products. In contrast to fermented dairy products, there is no defined and standardized starter culture for manufacturing cereal-based products. Since spontaneous fermentation is rarely suitable for large-scale commercial production, it is not surprising that manufacturers have started to adopt centuries-known dairy starters based on lactic acid bacteria (LABs) for the fermentation of cereals. However, little is known about the fermentation processes of cereals with these starters. In this study, we combined various analytical tools in order to understand how the most common starter cultures of LABs affect the most common types of cereals during fermentation. Specifically, 3% suspensions of rice, oat, and wheat flour were fermented by the pure cultures of 16 LAB strains belonging to five LAB species-Lacticaseibacillus paracasei, Lactobacillus delbrueckii, Lactobacillus helveticus, Streptococcus thermophilus, and Lactococcus lactis. The fermentation process was described in terms of culture growth and changes in the pH, reducing sugars, starch, free proteins, and free phenolic compounds. The organoleptic and rheological features of the obtained fermented products were characterized, and their functional properties, such as their antioxidant capacity and angiotensin-converting enzyme inhibitory activity, were determined.

Unveiling of the key pathway in flavor formation in fermented milk of Lactococcus lactis subsp. lactis via genomics and metabolomics

Lactococcus lactis subsp. lactis is a common starter culture in the dairy industry. In this study, the key pathway of five strains of Lactococcus lactis subsp. Lactis regarding their fermentation characteristics in milk systems were studied by metabolomic approach, fermentation characterization and sensory evaluation. Strains DSCAB11M15 and DYNDL21-2, which express the cell wall proteinase PrtM/P, exhibited rapid proliferation and acidification, with significant differences in volatile and non-volatile metabolites including upregulation of flavor compounds such as ethyl butyrate and 2,3-butanedione. Additionally, DYNDL21-2, which carries the α-ketoacid decarboxylase gene, significantly increased the content of 3-methyl-butyric aldehyde, a compound that imparts a caramel-like flavor, in fermented milk. This study offers guidance for the comprehensive investigation of starter cultures with multiple approaches.

The interaction effect of mixing starter cultures on homemade natural yogurt’s pH and viscosity

Dairy yogurts are common food products consumed by people all over the world. Due to the simple process, many people have made their own natural yogurt at home. The fermentation due to the starter culture causes the textural properties of dairy yogurt. However, the literature is surprisingly scarce on the topic of starter culture interactions in the development of textural properties of dairy yogurt. This study investigated the interaction effect of three common starter cultures, Lactobacillus acidophilus , Lactobacillus bulgaricus and S treptococcus thermophiles, on the viscosity of homemade yogurt. Using Design Expert software, a 10-run mixture model experiment was designed to examine the textural properties developed by single or multiple inoculation of these starter cultures. All yogurt formulations reached the isoelectric point of milk and had pHs in the range 3.97 to 4.32 . Yogurt formulations with L. acidophilus and S. thermophilus resulted in viscosities which were similar to commercial yogurt viscosity (1.77 Pa.s), while L. bulgaricus resulted in yogurt with a lower viscosity. Based on the mixture model, L. acidophilus had most influence on the yogurt viscosity, followed by S. thermophilus and L. bulgaricus . In conclusion, L. acidophilus can be used as a single starter culture or combined with other starter cultures to develop high viscosity homemade yogurt. A Combination of S. thermophilus and L. acidphilus can also be used to develop high viscosity yogurts. However, L. bulgaricus should not be inoculated alone or become a dominant ratio in multiple starter culture inoculation as it will decrease the overall homemade yogurt viscosity.

The interaction effect of mixing starter cultures on homemade natural yogurt’s pH and viscosity

Dairy yogurts are common food products consumed by people all over the world. Due to the simple process, many people have made their own natural yogurt at home. The fermentation due to the starter culture causes the textural properties of dairy yogurt. However, the literature is surprisingly scarce on the topic of starter culture interactions in the development of textural properties of dairy yogurt. This study investigated the interaction effect of three common starter cultures, Lactobacillus acidophilus, Lactobacillus bulgaricus and Streptococcus thermophiles, on the viscosity of homemade yogurt. Using Design Expert software, a 10-run mixture model experiment was designed to examine the textural properties developed by single or multiple inoculation of these starter cultures. All yogurt formulations reached the isoelectric point of milk and had pHs in the range 3.97 to 4.32. Yogurt formulations with L. acidophilus and S. thermophilus resulted in viscosities which were similar to commercial yogurt viscosity (1.77 Pa.s), while L. bulgaricus resulted in yogurt with a lower viscosity. Based on the mixture model, L. acidophilus had most influence on the yogurt viscosity, followed by S. thermophilus and L. bulgaricus. In conclusion, L. acidophilus can be used as a single starter culture or combined with other starter cultures to develop high viscosity homemade yogurt. A Combination of S. thermophilus and L. acidphilus can also be used to develop high viscosity yogurts. However, L. bulgaricus should not be inoculated alone or become a dominant ratio in multiple starter culture inoculation as it will decrease the overall homemade yogurt viscosity.

Prevalence of Lactobacillus bulgaricus and Streptococcus thermophilus stability in commercially available yogurts in Sri lanka

Aims and Objectives: Common starter cultures found in fermented milk products are Lactobacillus bulgaricus and Streptococcus thermophilus. The viability of these bacteria is important in order to gain health benefits. It is important to investigate the stability of commercially available yogurts with respect to starter cultures and the quality.Materials and Methods: Yogurt samples were collected from highly marketed different brands designated as A, B, C, D, E, F, G and H from different areas from Sri Lanka. MRS and M17 agar were used to enumerate L. bulgaricus and S. thermophilus respectively and a pH change was measured.Results: The pH values decreased significantly and only two of these products maintained 106 cfuml-1 viable count of L. bulgaricus till the end of the shelf life. All products showed the highest number of S. thermophilus.Conclusion: The pH of the yoghurts significantly change with the storage. For optimum benefits, the yogurt products should be consumed within seventh to fourteenth day from its manufacturing date. Only two of the yoghurt products maintained 106 cfuml-1 viable count of L. bulgaricus till the end of the expiry.Asian Journal of Medical Sciences Vol.7(5) 2016 97-101

Towards the development of a common starter culture for fufu and usi (edible starch): Screening for potential starters

Fermented cassava products like fufu and usi are important staple foods in many African homes. Natural fermentation time is usually long resulting in slower acidification and inconsistent nutritional composition of products which could be overcome with the use of starter culture. However, most available starters are used for single food fermentation and are uneconomical. This necessitates the development of a starter culture for multiple related food products to reduce cost. Hence, this study aimed at screening for potential starters in the development of a common starter culture for fufu and usi. Fresh, peeled, chipped and grated cassava tubers were spontaneously fermented and lactic acid bacteria were isolated from the fermenting mash at 24 hour intervals. Ninety eight (98) isolates were randomly picked. Lactobacillus plantarum had highest occurrence (50.0%) in both fermentations. All selected isolates did not hydrolyze starch, but produced linamarase and pectinase. Fermenting pH ranged between 6.50 and 3.58 during 72 hours fermentation. Lactic acid concentration ranged from 1.10 g/L to 1.78 g/L at 24 hours, 1.22 g/L to 2.45 g/L at 48 hours and 0.57 g/L to 2.55 g/l at 72 hours. The highest hydrogen peroxide concentration produced was 629 µg/L at 24 hours while the least was 136 µg/L at 72 hours. 1.08 g/L of diacetyl was the least concentration produced at 24 hours while the highest was 2.86 g/L at 48 hours. Five potential starters were identified as Lactobacillus pentosus F2A, L. plantarum subsp. argentolarensis F2B, L. plantarum F2C, L. plantarum U2A and L. paraplantarum U2C.

Towards the development of a common starter culture for fufu and usi (edible starch): Screening for potential starters

Fermented cassava products like fufu and usi are important staple foods in many African homes. Natural fermentation time is usually long resulting in slower acidification and inconsistent nutritional composition of products which could be overcome with the use of starter culture. However, most available starters are used for single food fermentation and are uneconomical. This necessitates the development of a starter culture for multiple related food products to reduce cost. Hence, this study aimed at screening for potential starters in the development of a common starter culture for fufu and usi.Fresh, peeled, chipped and grated cassava tubers were spontaneously fermented and lactic acid bacteria were isolated from the fermenting mash at 24 hour intervals. Ninety eight (98) isolates were randomly picked. Lactobacillus plantarum had highest occurrence (50.0%) in both fermentations.All selected isolates did not hydrolyze starch, but produced linamarase and pectinase. Fermenting pH ranged between 6.50 and 3.58 during 72 hours fermentation. Lactic acid concentration ranged from 1.10 g/L to 1.78 g/L at 24 hours, 1.22 g/L to 2.45 g/L at 48 hours and 0.57 g/L to 2.55 g/l at 72 hours. The highest hydrogen peroxide concentration produced was 629 µg/L at 24 hours while the least was 136 µg/L at 72 hours. 1.08 g/L of diacetyl was the least concentration produced at 24 hours while the highest was 2.86 g/L at 48 hours.Five potential starters were identified as Lactobacillus pentosus F2A, L. plantarum subsp. argentolarensis F2B, L. plantarum F2C, L. plantarum U2A and L. paraplantarum U2C.

The substitution of a traditional starter culture in mutton fermented sausages by Lactobacillus acidophilus and Bifidobacterium animalis

Common starter cultures used in fermented mutton sausages were substituted by probiotic strains of Lactobacillus acidophilus CCDM 476 and Bifidobacterium animalis 241a. Technological properties of the traditional and the probiotic sausages were compared. The potential probiotic effect was evaluated by enumeration of bifidobacteria and lactobacilli in stool samples of 15 volunteers before and after a 14-day consumption period. The numbers of lactobacilli (107cfu/g) and bifidobacteria (103cfu/g) in the final product did not affect the technological properties. The use of L. acidophilus as a starter culture was found more beneficial than the use of B. animalis. Even after 60days of storage, high counts of L. acidophilus (106cfu/g) were detected; on the other hand, the counts of B. animalis were under the detection limit. Regarding sensory properties, the probiotic products showed better texture, and, curiously, a reduction of the typical smell of mutton. The numbers of lactobacilli in stool samples increased significantly after the consumption of the probiotic sausages.

The influence of some starter cultures and GDL on the formation of biogenic amines in dry sausages

The influence of five common starter cultures and glucono-delta-lactone (GDL) on the formation of histamine, tyramine, putrescine, cadaverine, spermine and spermidine in dry sausages was studied. Sausages were manufactured in a pilot plant from two different batches of raw material. No major differences were observed between the starter cultures studied in the biogenic amine levels detected during ripening. The lowest levels of histamine were detected in sausages fermented by GDL and Staphylococcae with or without lactic acid bacteria as a starter culture. In pure culture studies performed with a turbidometric method in MRS broth, non-starter lactic acid bacteria isolated from sausages were found to be more sensitive to acidic conditions than the starter strains used in the study. The addition of 2% histidine to MRS broth resulted in a tremendous increase in histamine production (from 1-2 to 6000 ppm). However, in histidine-fortified MRS broth with GDL addition, only 54 ppm of histamine was formed. According to these results, the pH decrease caused by GDL addition decreases histamine formation in dry sausages and in MRS broth. The differences in pH decrease may be one reason for the very varying concentrations of histamine detected in retail dry sausages.