Sudhir Kumar Tomar

Current status and emerging role of glutathione in food grade lactic acid bacteria

Lactic acid bacteria (LAB) have taken centre stage in perspectives of modern fermented food industry and probiotic based therapeutics. These bacteria encounter various stress conditions during industrial processing or in the gastrointestinal environment. Such conditions are overcome by complex molecular assemblies capable of synthesizing and/or metabolizing molecules that play a specific role in stress adaptation. Thiols are important class of molecules which contribute towards stress management in cell. Glutathione, a low molecular weight thiol antioxidant distributed widely in eukaryotes and Gram negative organisms, is present sporadically in Gram positive bacteria. However, new insights on its occurrence and role in the latter group are coming to light. Some LAB and closely related Gram positive organisms are proposed to possess glutathione synthesis and/or utilization machinery. Also, supplementation of glutathione in food grade LAB is gaining attention for its role in stress protection and as a nutrient and sulfur source. Owing to the immense benefits of glutathione, its release by probiotic bacteria could also find important applications in health improvement. This review presents our current understanding about the status of glutathione and its role as an exogenously added molecule in food grade LAB and closely related organisms.

“Potential Health Benefits of Lunasin: A Multifaceted Soy-Derived Bioactive Peptide”

Bioactive peptides are small protein fragments derived from enzymatic hydrolysis of food proteins, fermentation with proteolytic starter cultures, and gastrointestinal digestion. These peptides have positive impacts on a number of physiological functions in living beings. Lunasin, a soy-derived bioactive peptide, is one of the most promising among them. Lunasin encoded within 2S albumin (GM2S-1) gene, identified as a novel peptide extracted from soybean seed. It is composed of 43 amino acid residues with a molecular weight of 5.5 kDa. Extensive scientific studies have shown that lunasin possesses inherent antioxidative, anti-inflammatory, anticancerous properties and could also play a vital role in regulating of cholesterol biosynthesis in the body. Its high bioavailability and heat stable nature allow its potential use as dietary supplement. The present review summarizes some of the potential health and therapeutic benefits of lunasin reported hitherto.

Food protein-derived bioactive peptides in management of type 2 diabetes

AbstractBackground Type 2 diabetes (T2D), one of the major common human health problems, is growing at an alarming rate around the globe. Alpha-glucosidase and dipeptidyl peptidase IV (DPP-IV) enzymes play a significant role in development of T2D. Hence, reduction or inhibition of their activity can be one of the important strategies in management of T2D. Studies in the field of bioactive peptides have shown that dietary proteins could be natural source of alpha-glucosidase and DPP-IV inhibitory peptides.PurposeThe purpose of this review is to provide an overview of food protein-derived peptides as potential inhibitors of alpha-glucosidase and DPP-IV with major focus on milk proteins.MethodsEfforts have been made to review the available information in literature on the relationship between food protein-derived peptides and T2D. This review summarizes the current data on alpha-glucosidase and dipeptidyl peptidase IV inhibitory bioactive peptides derived from proteins and examines the potential value of these peptides in the treatment and prevention of T2D. In addition, the proposed modes of inhibition of peptide inhibitors are also discussed.ResultsStudies revealed that milk and other food proteins-derived bioactive peptides play a vital role in controlling T2D through several mechanisms, such as the satiety response, regulation of incretin hormones, insulinemia levels, and reducing the activity of carbohydrate degrading digestive enzymes.ConclusionsThe bioactive peptides could be used in prevention and management of T2D through functional foods or nutraceutical supplements. Further clinical trials are necessary to validate the findings of in vitro studies and to confirm the efficiency of these peptides for applications.

Lactic acid bacteria as a cell factory for riboflavin production

Consumers are increasingly becoming aware of their health and nutritional requirements, and in this context, vitamins produced in situ by microbes may suit their needs and expectations. B groups vitamins are essential components of cellular metabolism and among them riboflavin is one of the vital vitamins required by bacteria, plants, animals and humans. Here, we focus on the importance of microbial production of riboflavin over chemical synthesis. In addition, genetic abilities for riboflavin biosynthesis by lactic acid bacteria are discussed. Genetically modified strains by employing genetic engineering and chemical analogues have been developed to enhance riboflavin production. The present review attempts to collect the currently available information on riboflavin production by microbes in general, while placing greater emphasis on food grade lactic acid bacteria and human gut commensals. For designing riboflavin‐enriched functional foods, proper selection and exploitation of riboflavin‐producing lactic acid bacteria is essential. Moreover, eliminating the in situ vitamin fortification step will decrease the cost of food production.

Multifaceted attributes of dairy propionibacteria: a review

Dairy propionibacteria are Generally Recognized as Safe (GRAS) status microorganisms which have been traditionally used for the manufacture of Swiss type cheeses. In the last two decades various added features and functionalities have been discovered and developed from these bacteria. Propionibacteria are robust organisms with remarkable adaptability to technological and physiological stress conditions. Besides, they also display a multitude of health promoting properties like modulation of gut microbiota, improved gut physiology and immunomodulation suggesting their promising probiotic potential. Propionibacteria produce an interestingly wide range of functional biomolecules like B group vitamins, trehalose, conjugated linoleic acid, propionic acid, bacteriocins, bifidogenic factors etc. These bacteria are thus now being explored for designing novel functional foods as well as for industrial production of nutraceuticals. Growing interest in these bacteria is fueled by the first whole genome sequencing of a Propionibacterium freudenreichii strain providing a platform for better understanding of various pathways and further improvement in related process technologies.

A method for estimation of urea using ammonia electrode and its applicability to milk samples.

A method for the estimation of urea in milk using ammonia electrode is described. Urea is first degraded by urease enzyme into ammonium ion and carbon dioxide at neutral pH. The ammonium ion is then converted into ammonia at alkaline pH. A linear inverse relationship was observed between logarithmic concentration of ammonia or urea and electrode response. Repeatability, expressed as a coefficient of variation, was 1.77% at a level of 8.92 mm-urea in milk. The method was validated in milk samples spiked with between 2 x 10-3 and 10 x 10-3 m-urea and recovery of added urea was quantitative. Whereas, preservative sodium azide at 0.5 g/l or 2 g/l level did not affect results, lower values of urea concentration in presence of Bronopol at 0.5 g/l were observed. Urea levels in milk samples estimated by this method were comparable to standard enzymatic method. The method is simple, fast and is not prone to interference from other milk constituents.

Response surface optimization of the cultivation conditions and medium components for the production of folate by Streptococcus thermophilus.

Optimization of the cultivation conditions and medium components for folate production by the highest folate producing Streptococcus thermophilus strain RD102 was carried out using a 23 central composite design and surface modelling method of response surface methodology. As folate production was observed to be growth-associated, hence the desired responses selected for the optimization were both folate production and growth. The selected factors based on preliminary investigations were incubation period, concentrations of p-amino benzoic acid (PABA) the growth precursor, and lactose as carbon source. The optimum concentrations of PABA and lactose were found to be 300 micropm and 3% respectively at 72 h incubation. The optimized conditions resulted in an increase in folate production by 26% compared with control conditions (0% PABA and lactose at 37 degrees C). Using the method of experimental factorial design and response surface analysis, it was possible to determine optimal operating conditions to obtain a higher folate production by Strep. thermophilus. Therefore, this study constitutes a step in developing strategies to modulate the folate level to a higher level.

Riboflavin and health: A review of recent human research

ABSTRACT There has lately been a renewed interest in Riboflavin owing to insight into its recognition as an essential component of cellular biochemistry. The knowledge of the mechanisms and regulation of intestinal absorption of riboflavin and its health implications has significantly been expanded in recent years. The purpose of this review is to provide an overview of the importance of riboflavin, its absorption and metabolism in health and diseased conditions, its deficiency and its association with various health diseases, and metabolic disorders. Efforts have been made to review the available information in literature on the relationship between riboflavin and various clinical abnormalities. The role of riboflavin has also been dealt in the prevention of a wide array of health diseases like migraine, anemia, cancer, hyperglycemia, hypertension, diabetes mellitus, and oxidative stress directly or indirectly. The riboflavin deficiency has profound effect on iron absorption, metabolism of tryptophan, mitochondrial dysfunction, gastrointestinal tract, brain dysfunction, and metabolism of other vitamins as well as is associated with skin disorders. Toxicological and photosensitizing properties of riboflavin make it suitable for biological use, such as virus inactivation, excellent photosensitizer, and promising adjuvant in chemo radiotherapy in cancer treatment. A number of recent studies have indicated and highlighted the cellular processes and biological effects associated with riboflavin supplementation in metabolic diseases. Overall, a deeper understanding of these emerging roles of riboflavin intake is essential to design better therapies for future.

Soy Bioactive Components in Functional Perspective: A Review

Functional foods are the focus of attraction for well-being. The healthy living of Asians may be attributed to a diet enriched with soy isoflavones viz. genistein and daidzein which fills the gap of proteinaceous diet in vegetarians. Several factors, such as administration, dosage, metabolism, ingestion of other pharmacological substances, type of estrogen receptors, and presence or absence of endogenous estrogen, affect the activities and bioavailability of isoflavones. The mode of therapeutic action could be either through the stimulation of estrogen receptors or by the non-involvement of estrogen receptors. Soy, due to its isoflavones content, serves as a balanced and remedial substitute in combating various lifestyle disorders, like cancer prevention, by interruption of the breakdown of extracellular matrix that surrounds growing vessels and tumors, lowering of lipid and blood insulin levels by regulating lipid and glucose metabolism, alleviation of menopausal symptoms, and osteoprotective effects by modulating estrogen receptors, thus acting as a safer switch to hormone replacement therapy, anti-hypertensive effect which may also contribute to cardioprotective, anti-oxidative effect, regulation of cognitive functions, and many others. Therefore, it could be regarded as a valuable therapeutics. However, since soy isoflavones also act as endocrine disruptors, they also possess some negative effects. Concerns have been raised in relation to thyroid function abnormality. In view of the previously mentioned facts an attempt has been made to review the literature available on both beneficial as well as deleterious role of isoflavones, soy derived bioactive compounds.

Effect of developed acidity and neutralization of milk on sensory, microstructural and textural changes in khoa prepared from cow and buffalo milk

Khoa is a heat desiccated milk product which serves as base material for traditional dairy based Indian sweets. Sensory, textural and microstructural changes in khoa were studied to assess the effect of developed acidity and neutralization of milk. Noticeable changes were observed in sensory, textural and micro structural quality of khoa as affected by quality of milk. Lower hardness, springiness, cohesiveness and accordingly, gumminess and chewiness were observed in khoa manufactured using neutralized milk due to higher moisture retention as compared to control and acidic milk khoa. It was also evident from the Scanning Electron Microscopy that higher moisture retention in neutralized milk khoa resulted in elongation of native microstructure of khoa by suppressing the grain formation leading to smooth and plain surface while, developed acidity in milk resulted in greater granule formation in the resulting khoa causing shrinkage of native microstructure and acidic flavour in khoa. Similarly, acidification and subsequent neutralization of milk adversely affected sensory attributes of resulting khoa.