Munir Ahmad Sheikh

Effect of fortification on physico-chemical and microbiological stability of whole wheat flour

Stability of fortified whole wheat flour (WWF) was evaluated using NaFeEDTA, elemental iron, ZnSO4 and ZnO as fortificants. Fortified WWF was stored in tin boxes and polypropylene bags for 60 days under ambient storage condition (ASC) and controlled storage condition (CSC). Fortification significantly (p⩽0.05) decreased moisture and protein content and increased ash content to 5.44%, 6% and 23%, as compared to control. Fortified WWF, assayed periodically for mould contamination manifested a significant inhibition (∼1 log reduction) in flours containing elemental iron. Low storage temperature and relative humidity (RH) indicated lower level of mould count during extended storage time. Tin boxes, as storage material, exhibited a better protection against mould attack, acting as an effective barrier for moisture. Fortificants exerted a slight deteriorative effect on texture characteristics of the chapattis made of these flours but chapattis were still accepted by the judges. Zinc fortificants seemed like having little or no effect on the quality of the flours and chapattis, made of such flours. Shelf life of fortified flour may be extended by using elemental iron as fortificant and storing the product in tin boxes under relatively low temperature and RH.

XRD studies of chitin-based polyurethane elastomers.

Chitin-based polyurethane elastomers (PUEs) were synthesized by step growth polymerization techniques using poly(epsilon-caprolactone) (PCL) varying diisocyanate and chain extender structures. The viscosity average molecular weight (M(v)) of chitin was deduced from the intrinsic viscosity and found; M(v)=6.067 x 10(5). The conventional spectroscopic characterization of the samples with FTIR, (1)H NMR and (13)C NMR were in accordance with proposed PUEs structure. The crystalline behavior of the synthesized polymers were investigated by X-ray diffraction (XRD), differential scanning calorimetery (DSC) and loss tangent curves (tan delta peaks). The observed patterns of the crystalline peaks for the lower angle for chitin in the 2theta range were indexed as 9.39 degrees, 19.72 degrees, 20.73 degrees, 23.41 degrees and 26.39 degrees. Results showed that crystallinity of the synthesized PUEs samples was affected by varying the structure of the diisocyanate and chain extender. Crystallinity decreased from aliphatic to aromatic characters of the diisocyanates used in the final PU. The presence of chitin also favors the formation of more ordered structure, as higher peak intensities was obtained from the PU extended with chitin than 1,4-butane diol (BDO). The value of peak enthalpy (DeltaH) of chitin was found to be 47.13 J g(-1). The higher DeltaH value of 46.35 J g(-1) was found in the samples extended with chitin than BDO (39.73 J g(-1)).

Food Fortification Strategy—Preventing Iron Deficiency Anemia: A Review

Iron deficiency anemia (IDA) is a significant challenge in developing countries. It increases the risk of premature delivery and low birth weight. In children, IDA retards growth, impairs cognitive performance, and reduces physical activity. It also accelerates the mortality and morbidity rate in women. The key factors responsible include dietary elevated iron demand, socioeconomic, and disease status. To overcome IDA, disease control measures, dietary diversification, supplementation and iron fortification in food have been adopted. Iron fortification in food is considered a long term and sustainable strategy in the present scenario. For an efficient fortification program, the combination of iron fortificants and food vehicle must be safe, acceptable, and consumed by the target population. Moreover, it should not adversely affect acceptability and stability of the end product.

Evaluation of biocompatibility and mechanical behavior of chitin-based polyurethane elastomers. Part-II: Effect of diisocyanate structure.

Chitin-based polyurethane elastomers having potential for biomedical applications with tunable mechanical properties were synthesized by step growth polymerization techniques using poly(epsilon-caprolactone) (PCL) with different diisocyanates. The prepolymer was extended using chitin and/or 1,4-butane diol (BDO). The structures of the resulted polymers were determined by Fourier transform infrared (FTIR), 1H NMR and 13C NMR spectroscopic techniques. The effect of structure of diisocyanates and chain extenders on mechanical properties and in vitro biocompatibility were investigated. The results revealed that the final polymers extended with chitin are preferred candidates for surgical threads with on going investigations into their in vitro biocompatibility and non-toxicity.

Strain Improvement Through UV and Chemical Mutagenesis for Enhanced Citric Acid Production in Molasses-Based Solid State Fermentation

Aspergillus niger was subjected to UV radiation and chemical mutagenesis to develop its hyper-producing mutants for enhanced citric acid production. Ethyl methane sulfonate (EMS) and Ethidium bromide (EB) were used for chemical mutagenesis of Aspergillus niger. UV, and chemically treated mutants of Aspergillus niger were identified by using 2-deoxy, D-glucose as selective marker. The selected mutants were cultured in solid state fermentation (SSF) of sugarcane molasses medium (10%) using corn cobs, banana stalk, sugarcane bagasse, wheat straw, and wheat bran as carrier substrates. After pH adjustment and sterilization, the triplicate flasks were inoculated with 5 mLof homogenous spore suspensions of selected mutants of A. niger and the flasks were subjected to SSF under still culture conditions. The mutant EB-3 (treated with 1 mg/mL ethidium bromide for 120 min) giving highest citric acid yield (64.2 mg/mL) in 72 h was selected as hyper-producing mutant. Citric acid production process using EB-3 mutant was then optimized to enhance citric acid production by the mutant in SSF. Aspergillus niger EB-3 mutant could produce 67.72 mg/mL citric acid in 72 h using banana stalks as support material under optimum conditions of pH (pH 6), incubation temperature (35°C) and inoculum size (5 mL) in SSF.

Thermal Characterization of Purified Glucose Oxidase from A Newly Isolated Aspergillus Niger UAF-1

An intracellular glucose oxidase was isolated from the mycelium extract of a locally isolated strain of Aspergillus niger UAF-1. The enzyme was purified to a yield of 28.43% and specific activity of 135 U mg−1 through ammonium sulfate precipitation, anion exchange and gel filtration chromatography. The enzyme showed high affinity for D-glucose with a Km value of 2.56 mM. The enzyme exhibited optimum catalytic activity at pH 5.5. Temperature optimum for glucose oxidase, catalyzed D-glucose oxidation was 40°C. The enzyme showed a high thermostability having a half-life 30 min, enthalpy of denaturation 99.66 kJ mol−1 and free energy of denaturation 103.63 kJ mol−1. These characteristics suggest the use of glucose oxidase from Aspergillus niger UAF-1 as an analytical reagent and in the design of biosensors for clinical, biochemical and diagnostic assays.

Reduction of Cyanogenic Compounds in Flaxseed (Linum usitatissimum L.) Meal Using Thermal Treatment

Flaxseed (Linum usitatissimum L.) provides multiple nutritional benefits, including high quality protein, dietary fiber, and is the most abundant source of α-linolenic acid (C18:3). However, the presence of anti-nutritional factors, such as cyanogenic compounds, restricts flaxseeds consumption as a food or feed. This study investigated the reduction of cyanogenic compounds, measured as hydrocyanic acid (HCN), in full-fat flaxseed using extrusion processing without a die by following the response surface methodology. The ranges of processing variables selected were: barrel exit temperature of 76.3–143.6°C; screw speed of 59.6–160.5 rpm; and feed rate of 26.4–93.6 kg/h. The experimental values of HCN reduction obtained were from 60.8 to 86.6%. Optimum extrusion conditions of barrel exit temperature, screw speed, and feed rate were found to be 143.6°C, 133.5 rpm, and 57.8 kg/h for maximum (89.1%) reduction of HCN. This effect was mainly dependent on barrel exit temperature, whereas screw speed and feed rate had no or minimal effect. The mutual interaction effect of barrel exit temperature and screw speed was found to be significant (p ≤ 0.01). The degree of correlation (R2) for HCN reduction was 97.2%, which showed the validity of applied second-order response model. The results of this study demonstrated that significant reduction of HCN in flaxseed can be achieved commercially using an extruder without a die.

Enhanced production and characterization of a novel β- D-glucose:oxygen-1-oxidoreductase by using Aspergillus niger UV-180-C mutant strain

Along with other emerging health consequences, diabetes mellitus is one of the critical threats spreading all over the world with continuity. The investigation of glucose level in diabetic patients requires the key enzyme β-D-glucose:oxygen-1-oxidoreductase/glucose oxidase, where its optimized production by mutant derived strain could affect the economic burden and accuracy of the test. Wild type Aspergillus niger was subjected to ultraviolet radiation for enhanced production of glucose oxidase. It was found that UV-180-C is a potential mutant derived strain, screened by using 2-deoxy-Dglucose. Optimum production of glucose oxidase from A. niger UV-180-C was carried out by using CSL (2%), fermentation period (36 h), pH (5.5 and 4.5 for wild and mutant respectively), temperature (30°C), MgSO 4 .7H 2 O (0.0%), CaCO 3 (0.1%), KH 2 PO 4 (0.8 and 1.0% for wild and mutant strains), Urea (0.3%). Crude enzyme was subjected to ammonium sulfate precipitation and resulted into 145.8 UmL -1 activity. Glucose oxidase from mutant derived A. niger exhibited optimum pH at 6, temperature 20°C, K m 10mM and V max 142 UmL -1 . The pyridoxal phosphate caused significant inhibition to the enzyme which indicates the presence of lysyl residues near or at the active site of the enzyme from both wild and mutant derived strains. Key words :Enhanced production, UV radiations, β-D-glucose:oxygen-1-oxidoreductase, A. niger

Determination of in vitro antidiabetic effects of Zingiber officinale Roscoe

Aqueous extracts of Zingiber officinale rhizomes were studied to evaluate their antidiabetic effects on protein glycation and on the diffusion of glucose in vitro in the present study. Zingiber officinale rhizome aqueous extract were examined at concentrations of 5, 10, 20 and 40 g/L. The antidiabetic effects were found to be dose-dependent. Antidiabetic potential of Zingiber officinale was mainly through inhibition of the glucose diffusion and to a limited extent by reducing the glycation. However, further studies are needed to determine in vitro effects of therapeutic potential by restraining postprandial glucose absorptions and plasma protein glycations in diabetic subjects.

Inhibition of protein glycation and advanced glycation end products by ascorbic acid

Advanced glycation end products (AGEs) formation is increased in diabetes mellitus, leading to microvascular and macrovascular complications. Recently, much attention has been focused on natural and synthetic inhibitors to delay the onset or progression of diabetes and its comorbidities. Ascorbic acid (AA) can react with proteins, including hemoglobin and possibly interfere with protein glycation process. An in vitro glycation model containing plasma from type 2 diabetic and non-diabetic healthy volunteers together with glucose as glycating agent was used to study antiglycation activity of AA. Samples with different concentrations of glucose and AA were incubated for five weeks at 37°C. Nonenzymatic glycation (NEG) was quantitated by thiobarbituric acid calorimetry and AGEs were measured by enzyme linked immuno-sorbent assay (ELISA). The NEG and AGEs levels were reduced by AA. Increasing the AA concentrations greatly diminished protein glycations, indicating dose-dependent effects of AA. Plasma NEG and AGEs were decreased with an average of 20 to 26% (p < 0.05) and 26 to 28% (p < 0.05). A significant correlation was found between the glycation inhibition and the inhibition of AGE formation (p < 0.05). The antiglycation role of AA is evident in the present study and it also indicates the possibility of inexpensive, relatively non-toxic vitamin therapy for the prevention and treatment of diabetic complications. It is plausible that AGEs inhibition by AA may also form the basis for future intervention strategies in both diabetic and non-diabetic individuals. Keywords: Diabetes mellitus, glycation, advanced glycation end products, hyperglycemia, ascorbic acid