Search results

The use of lactic acid bacteria in food production is perhaps one of the oldest examples of biotechnology. It is probable that fermented milk has been consumed since man started milking animals, possibly as far back as 11,000 years ago. Over the years, numerous fermented foods have been developed, each with its own microbiological flora involved in production. These fermented foods have arisen without microbiological skills or knowledge; only relatively recently have we been able to understand the biological process underlying food fermentation by lactic acid and other bacteria.

Probiotics are known to extend health benefits and therefore may be included during yoghurt manufacture to enhance its prophylactic properties. Different probiotic strains may exhibit diverse biotechnological behaviour in association with yoghurt cultures, therefore interactive behaviour amongst probiotic and yoghurt cultures must be evaluated prior to their commercial application. This paper aims to assess the effect of inclusion of different probiotic cultures on various biotechnological (technological, dietetic and prophylactic) characteristics of yoghurt cultures.

Yoghurt was assessed for technological characteristics based on acidification and flavour production, dietetic characteristics based on proteolytic activity, vitamin synthesis and L (+) lactic acid production and prophylactic characteristics based on β‐galactosidase activity, antibacterial spectrum, viability in product as well as during gastro‐intestinal transit, intestinal colonization, immunomodulation, anti‐carcinogenicity and hypocholesterolemic effect.

Different probiotic cultures exhibited diverse technological, dietetic and prophylactic behaviour in association with yoghurt cultures. Functional properties of traditional yoghurt could be enhanced with the combined introduction of probiotic cultures such as Bifidobacterium bifidum, Bifidobacterium infantis and Lactobacillus acidophilus and the resultant product may be recommended for consumption as a dietary adjunct.

The paper shows that combined introduction of probiotic cultures such as B. bifidum, B. infantis and L. acidophilus, as microbial additives during the manufacture of yoghurt would result in a product with enhanced functional properties.

Gamma-aminobutyric acid (GABA) is a four-carbon and nonprotein amino acid, made by various microorganisms, especially lactic acid bacteria (LAB) and probiotics. GABA has various physiological roles, for instance, insomnia, depression, hypotensive activity as well as diuretic effects. The production of GABA-based foods is a favorable result from GABA’s biological and functional properties. The purpose of this study is to investigate different methods of improving GABA production in probiotics and LAB to select the superlative method and bacterial strain.

In this review paper, all articles from five electronic databases containing Google Scholar, Web of Science, PubMed, Scopus and Science Direct were considered from 2000 to January 11, 2023, with keywords “Optimization” OR “Enhance” OR “Increase” AND “Gamma-aminobutyric acid” OR “GABA” AND “Probiotics” OR “Lactic acid bacteria” and selected according to the purpose of the study.

It seems that among all the investigated methods, an effective fermentation procedure with optimal conditions including fermentation medium, 5 L; glutamic acid, 295 g/L; incubation temperature, 32°C; inoculum, 10% (v/v); and agitation, 100 rpm, after 48 h of fermentation led to producing 205,800 mg/L of GABA from the effective bacterial strain Lactobacillus brevis NCL912.

With a simple but optimized fermentation, L. brevis NCL912 can be used for the efficient GABA production in the pharmacy and food factories.

The Indian diet is rich in all the essential nutrients required for the well-being of human life. Probiotics have always been part of our traditional diet but microbiota of traditional fermented foods has not been explored. This study aims to analyse various traditional Indian fermented products for their probiotic nature.

Fermented indigenous products such as kanji, vegetable pickles and curd were prepared under controlled conditions and stored at ambient temperatures for shelf life studies. During the shelf life study, pH, titratable acidity and Lactic acid bacteria (LAB) count were estimated.

LAB counts ranged between 106 and 108 cfu/g in all the products, reflective of the probiotic nature of the products. Growth was observed even at low pH of 2.77 in product such as lemon chilli and ginger pickle. The 16S RNA-based sequencing technique was used for the identification of probiotic organisms present in the product. Enterococcus lactis, enterococcus durans, bacillus subtilis and lactobacillus plantarum were detected in the products.

These observations emphasise the need to undertake in-depth analysis of the viability of LAB in these fermented Indian foods for improving their nutritional properties. A need exists to explore and popularise more indigenous fermented products as probiotics.

India has a very rich and diverse food culture which differs from one region to other. This is because of difference in climatic conditions which has led to variety of food products. There are many products prepared locally and are not studied scientifically. This study aimed to explore these products for the presence of LAB which could have a probiotic potential.

Discusses the exploitation of the metabolic activities of the lactic acid bacteria in the manufacture of dairy products. Gives the two main “starter culture” groups as: (1) mesophiles; and (2) thermophiles; and considers the relevance to the consumer of the presence of species from these groups in food products. Concludes that the presence of viable mesophiles is of limited significance in nutritional terms; but that the presence of thermophiles in bio‐yogurts and similar items will benefit the consumer, if these items are consumed on a regular basis.

Green leafy vegetables (GLVs) are important components of a balanced diet especially in developing countries where the major requirements of micronutrients are met. However, GLVs also contain significant amounts of oxalate, nitrate and nitrites, whose role in the human diet is constantly changing. The current study explored the behavior of nitrate, nitrites and oxalate in lactic-fermented GLVs with an intention to develop functional foods based on them.

Selected strains of beneficial lactic acid bacteria were used for the controlled fermentation of GLV, while an identical portion was subjected to spontaneous fermentation. The nitrate and nitrites were monitored spectrophotometrically, while oxalate contents were quantified by both titrimetric and by high-performance liquid chromatography throughout the duration of fermentation.

More than 90 per cent of individual constituents studied remained intact in the GLVs paste after the six-day controlled fermentation period. However, there was significant difference between the controlled and spontaneously fermented samples in terms of oxalate, nitrate and nitrite contents.

Controlled lactic fermentation although superior in all other aspects may not be able to lower the anti-nutrients present. The advantages of spontaneous fermentation vis-à-vis controlled fermentation are discussed. The work will bring out the importance of the beneficial effects of GLVs and the effect of lactic fermentation.

The purpose of the paper is to show that traditionally, kefir was obtained by fermenting milk with kefir grains. Wide variation in microflora of kefir grains makes it difficult to obtain an optimal and uniform starter culture necessary for obtaining a quality kefir. Reviewed literature on microbiological and technological innovations in kefir production would enrich the scientific knowledge resulting in production of kefir with superior physical, chemical, nutritional, therapeutic and sanitary qualities.

An attempt is made to highlight the microbiological and technological aspects of kefir production with regard to the microflora of kefir grains, suitability of different types of milk, treatment of milk, starter inoculation and incubation, packaging, storage and post‐production treatment of kefir as well as methods of preservation of kefir grains.

Diverse microflora of kefir grains is the prime cause for the wide variation in kefir quality. Production of kefir is based on symbiotic relation between lactic acid bacteria and yeasts and the type of milk, their heat‐treatment, size of inoculating starters and temperature of incubation influence their metabolic activities. Application of a suitable combination of lactic acid bacteria and yeasts would enable production of kefir with more uniform product with specific properties Packaging of kefir in a suitable container and storage at low temperature are suggested to retain its qualities.

Fermentation of milk with a suitable starter combination consisting of lactic acid bacteria and yeasts rather than application of kefir grains during the production of kefir would be more scientific to yield a product with enhanced nutritional and therapeutic qualities.

Kefir is a traditional fermented dairy beverage that has numerous health benefits due to the presence of bacteria and yeasts in an exopolysaccharide matrix. This study aims to isolate and identify beneficial microorganisms and evaluate the antimicrobial activity of kefir beverage against two important food-borne pathogens including Salmonella Typhimurium and Listeria monocytogenes.

Microorganisms were identified by the polymerase chain reaction with specific primers, and antimicrobial activity was evaluated by the disk diffusion method.

The following microorganisms were identified as natural inhabitants of the kefir grains: Leuconostoc lactis, Lactococcus lactis subspecies lactis, Streptococcus cremoris, Enterococcus faecalis, Enterococcus faecium, Lactobacillus helveticus, Leuconostoc mesenteroides, Lactobacillus fermentum, Lactobacillus reuteri, Lactobacillus plantarum, Lactobacillus casei, Bifidobacterium langum, Saccharomyces cerevisiae and Pichia fermentas. Also, the results obtained from the disk diffusion method showed the inhibitory effect of kefir milk on Salmonella Typhimurium and Listeria monocytogenes with an inhibitory average diameter of 8.3 ± 4–9.1 ± 2.8 and 3.4 ± 3–6.6 ± 3 mm, respectively.

The results of this study showed that Iranian traditional kefir beverage contained different species of lactic acid bacteria and yeasts and has antimicrobial activity against two important food-borne pathogens, Salmonella Typhimurium and Listeria monocytogenes, which the highest inhibitory effect was observed against Salmonella Typhimurium.

Since a sound detoxification method is needed for controlling aflatoxin B₁ (AFB₁), as one of the most harmful mycotoxins in animal production and food industry, this study was performed. The paper aims to discuss these issues.

This study was conducted to examine the ability of Lactobacillus rhamnosus strain GG to remove AFB₁ from liquid media. The binding of AFB₁ to Lb. rhamnosus GG was studied for viable, heat-killed and acid-killed bacteria. AFB₁ at concentrations (5, 10 and 20 μg/l) was added to the bacterial culture (109 cfu/ml) in MRS broth medium and incubated at 25°C for 4, 12 and 24 h. The aflatoxin-binding capacity of the strain was quantified by the amount of unbound AFB₁ using ELISA technique.

Results showed the AFB₁-binding capacity of viable, heat-killed and acid-killed bacteria was about 43, 49 and 50 percent, respectively. The percentage of AFB₁ removed was the highest amount in low (5 μg/l) and high (20 μg/l) concentrations, and there was no significant difference between them (p=0.05). These findings suggest that lactic acid bacteria can be exploited as an approach to detoxification of aflatoxins from foods.

This method is safe because non-viable bacteria have more ability to remove toxin than viable bacteria, and also it is an effective method with 50 percent approximately toxin removal.

Since there has been no research on the ability of this strain on the removal of AFB₁, the authors assessed the ability of the strain in high levels of AFB₁.

The purpose of this study was to assess the bacterial viability, antioxidative activity, antimutagenicity and sensory evaluation of fermented onion types by using probiotic starters after fermentation at 37 °C for 24 hours and storage in the refrigerator for 28 days.

For onion fermentation, Lactobacillus acidophilus (LA-5), Bifidobacterium bifidum (BB-12), and Streptococcus thermophilus (ST) were utilised. This research was conducted on three types of onion: white onion, red onion and scallion. With a 5% brine solution, the onions were sliced into 3-5 cm long and 1-2 cm wide slices. The process of fermentation was achieved by adding 2% (10⁸ CFU/ gm) of fresh probiotic starter and incubating it for 24 hours at 37 °C. The fermented onion samples were kept in the refrigerator for 28 days. After fermentation and storage, the pH and total acidity were estimated, the vitality of probiotic bacteria was evaluated in samples of the onion species. The Gas chromatography-mass spectrometry (GC-MS) technique was used to identify the bioactive components in fermented onion types. The antioxidant activity of fermented onions was measured using the 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) radical scavenging activity assay and the hydroxyl radical scavenging activity test. The Ames test was used to detect the antimutagenicity of fermented onion samples.

After fermentation, the fermented scallion (p = 0.036) has the highest vitality of all the starter bacteria species. The fermentation of onion types produced a pH of between 4.1–4.7 and 0.19–0.23% total acidity, which is in the range of reduced 3.1–3.5 pH values and 0.42–0.63% total acidity after 28 days. The viability of Lactobacillus acidophilus and Bifidobacterium bifidum in fermented scallions was Log. 7.79 and 7.57 CFU/gm. The GC-MS technique found 14 bioactive compounds in fermented white onions and 13 compounds in fermented white onions, with 15 compounds in scallion fermentation. The majority of these bioactive compounds are strong antioxidants. The antioxidant properties of fermented scallion significantly increased after 28 days of storage time, showing an inhibitory effect on the DPPH assay (p = 0.02) and the scavenging activity of the hydroxyl radical assay (p = 0.01). Sensory evaluation tests revealed that the fermented scallion was a suitable product in terms of appearance, aroma and overall acceptability.

Commercially accessible probiotic foods account for a sizable portion of the consumer market. Furthermore, as consumer interest in healthy eating grows, so does demand for plant-based goods. All onion types fermented with probiotic bacteria have many chemical compounds that have both antioxidant and carcinogenic activity. The fermented scallion onion sample was significantly superior to the rest of the other types of onions.