Rajesh Kumar Bajaj

Preparation of iron bound succinylated milk protein concentrate and evaluation of its stability.

Major problems associated with the fortification of soluble iron salts include chemical reactivity and incompatibility with other components. Milk protein concentrate (MPC) are able to bind significant amount of iron due to the presence of both casein and whey protein. MPC in its native state possess very poor solubility, therefore, succinylated derivatives of MPC (succ. MPC) were also used for the preparation of protein-iron complex. Preparation of the complex involved centrifugation (to remove insoluble iron), ultrafiltration (to remove unbound iron) and lyophilisation (to attain in dry form). Iron binding ability of MPC enhanced significantly (P<0.05) upon succinylation. Stability of bound iron from both varieties of complexes was monitored under different conditions encountered during processing. Higher stability (P<0.05) of bound iron was observed in succ. MPC-iron complex than native protein complex. This method could be adopted for the production of stable iron enriched protein, an organic iron source.

Bioactive Peptides in Yogurt

Abstract Yogurt is a coagulated milk product obtained from lactic acid fermentation by the action of Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophilus. Proteolytic activity of S. thermophilus and L. delbrueckii ssp. bulgaricus indicate that both organisms possess different exopeptidases and peptidases. Bioactive peptides have been defined as specific protein fragments that have a positive impact on body functions or conditions and may ultimately influence health. At present, milk proteins are considered the most important source of bioactive peptides. Bioactive peptides may affect the major body systems—namely, the cardiovascular, digestive, endocrine, immune, and nervous systems. The strain should not be too proteolytic and must have the right specificity to give high concentrations of active peptides. The concentration of bioactive peptides appears to rely on a balance between their formation and further breakdown that in turn depends on storage time and conditions.

Buffalo Milk Casein Derived Decapeptide (YQEPVLGPVR) Having Bifunctional Anti-inflammatory and Antioxidative Features Under Cellular Milieu

Antioxidants having anti-inflammatory potential will be useful in reducing the progression of many lifestyle associated diseases. Under present investigation, buffalo casein derived decapeptide (YQEPVLGPVR) displayed anti-inflammatory response by suppressed (p < 0.01) murine splenocytes proliferation, reduced inflammatory cytokine levels (Interferon-γ) besides elevated levels of regulatory cytokines (Interleukin-10 and Transforming Growth Factor-β) in splenocyte culture supernatant. Decapeptide also improved the phagocytosis (p < 0.01) of peritoneal macrophages. Subsequently, antioxidative feature of the peptide was also identified by efficient (p < 0.01) free radical scavenging using chemical assays (ABTS: 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid and ORAC: oxygen radical absorption capacity methods) which was later confirmed for protective action against H2O2 mediated oxidative stress on intestinal epithelial cells by inhibition (p < 0.01) of cellular ROS generation, oxidative products formation along with elevated (p < 0.01) activities of antioxidative enzymes (catalase and glutathione peroxidase). Declined (p < 0.01) mRNA expression of a transcription factor (Nuclear factor erythroid 2-related factor: Nrf-2) involved in redox signalling further established the protective effect of peptide against oxidative stress induced injury.

Bio-accessible milk casein derived tripeptide (LLY) mediates overlapping anti- inflammatory and anti-oxidative effects under cellular (Caco-2) and in vivo milieu

Inflammation and oxidative stress are closely linked patho-physiological processes which occur concurrently in many diseased conditions. Recently, interdependence between these two processes explains the antioxidant paradox associated with failure to select appropriate agents required for prevention of diseases known to be induced by oxidative stress. Present study established the overlapping anti-inflammatory and anti-oxidative potential along with bio-accessibility of milk casein derived tripeptide (LLY). Tripeptide exhibited anti-inflammatory response under ex vivo conditions by suppressing (P<.01) mice splenocytes proliferation and modulating their cytokines (IFN-γ, IL-10 and TGF-β) with improved phagocytosis of peritoneal macrophages. Conversely, tripeptide displayed extraordinary radical scavenging ability and cellular anti-oxidative potential using chemical assays and H2O2 induced oxidative stress model on Caco-2 cells. Under cellular assessment, on one hand tripeptide inhibited (P<.01) intracellular ROS generation and reduced MDA and protein carbonyls but on the other also increased (P<.01) the activity of anti-oxidative enzyme, catalase without much effect on SOD and GPx. This anti-oxidative potential was further established by studying relative expression of genes (Nrf-2 and Keap1) and Nrf-2 nuclear translocation associated with anti-oxidative signaling in Caco-2 cells. Bio-accessibility of tripeptide and its intact transport across Caco-2 cell monolayer was also found to be 1.72±0.22% through PepT1 mediated transport mechanism. Besides, tripeptide displayed strong anti-oxidative and anti-inflammatory potential under in vivo conditions in mice against ethanol induced oxidative stress by elevating (P<.01) liver GSH content and by decreasing (P<.01) the activities of anti-oxidative enzymes, MDA along with reduced expression of CYP2E1, PPAR-α, TNF-α and COX-2 genes than ethanol control.

Evaluation of casein & whey protein hydrolysates as well as milk fermentates from Lactobacillus helveticus for expression of gut hormones

Background & objectives: Milk proteins play a beneficial role in the regulation of food intake, postprandial glycaemia and enteroendocrine hormone secretions and thus are receiving considerable attention for the management of metabolic inflammatory disorders such as type 2 diabetes mellitus (T2DM). The objective of this study was to evaluate the efficacy of peptide/s obtained from milk proteins (casein and whey) as well as from the milk fermented with Lactobacillus helveticus as secretagogues for gut hormones and to purify and characterize the active peptides. Methods: Effect of hydrolysates of casein protein (CP) and whey protein (WP) and L. helveticus fermented milk on the expression of proglucagon, pro-gastric inhibitory peptide (GIP) and cholecystokinin (CCK) genes was monitored by real-time quantitative polymerase chain reaction. The active glucagon-like peptide-1 (GLP-1) secretion was also quantitatively measured using ELISA. Results: Hydrolysates of CP and WP as well as fermentates of L. helveticus induced the proglucagon, pro-GIP and CCK expression and secretion of GLP-1 in STC-1 (pGIP/Neo) cells. However, intact casein exhibited maximum GLP-1 secretion and proglucagon expression. Two active peptides (F5 and F7) derived from CP1 and WP3 hydrolysates having the ability to upregulate the GLP-1 secretion by 1.6 and 1.8 folds were obtained, and the mass was found to be 786 and 824 Da, respectively, as determined by electrospray ionization-mass spectrometry. However, no single active peptide from L. helveticus fermented milk could be obtained. Interpretation & conclusions: Casein as well as fermentates obtained from L. helveticus fermented milk showed higher potential for GLP-1 induction. These can be explored as novel therapeutics to T2DM effectively after demonstrating their in vivo efficacy in appropriate animal models.