SOLUBILISATION OF NITROGENOUS CONSTITUENTS OF BREWERS' SPENT GRAIN

The extraction of nitrogenous material from Brewers' spent grain (BSG) by solvents (water, sodium chloride solution, aqueous alcohol, acidic and alkaline solutions) commonly used to extract cereal proteins, resulted in the relatively low (0·2 to 8·5%) recovery of the total nitrogen. The recovery of nitrogenous material by the use of aqueous alkaline solutions was increased from 3–4% to 41% when the BSG was subjected to cellulase incubation prior to extraction. Approximately 75% of the nitrogen was solubilized with trifluoracetic acid. Detergent solutions (acid, neutral) solubilized more than 80% of the total nitrogen of the BSG. The low solubility of the nitrogenous constituents by conventional protein solvents could be the result of association between cellulosic material and protein.     

Constitution of leguminous seeds. Polyacrylamide-disc gel electrophoresis of acid soluble and acid precipitated proteins prepared from baby lima beans

Acid soluble proteins (bipyramidal crystalline, 76.9% protein, 15% carbohydrate) prepared by citric acid extraction and acid precipitated proteins (amorphous, 64.2% protein, 11.3% carbohydrate) prepared by alkali extraction from baby lima beans (Phaseolus lunatus) were found to behave in a similar manner under alkaline conditions (pH 8.9) of electrophoresis (absence of urea). Striking differences were observed in the behaviour of the two types of protein preparations when electrophoresis was performed under acidic conditions (pH 4.5; absence and presence of urea and a mixture of urea and 2-mercaptoethanol) and in the presence of sodium dodecyl sulphate.     

Structural and Rheological Properties of Succinoglycan Biogums Made from Low-Quality Date Syrup or Sucrose Using Agrobacterium radiobacter Inoculation

This study examines and compares the structural and rheological properties of succinoglycan exopolysaccharide made by fermentation of sucrose or date syrup at identical temperature, pH, and total soluble solid. Using thin-layer chromatography (TLC), Fourier transform infrared (FTIR) spectroscopy, and rotational viscometery structural and rheological properties of prepared exopolysaccharides were assessed. The variables under studies were biogum concentrations (0.5%, 1.0%, 1.5%, and 2.0% w/w), temperature (5, 25 and 40°C), and pH (2.5, 4.0, 7.0, and 10.0). Results revealed that the quantity of exopolysaccharide produced in the date syrup (DSE) medium was three to five times greater than that of sucrose (SE) medium. The biogums exhibited non-Newtonian, shear-thinning behavior, and the viscosity of DSE was higher than SE at all tested concentrations. The TLC and FTIR spectroscopy assessments designated that the biogum is composed of glucose and galactose units, carrying a carboxylic group and indicated the presence of succinoglycan. The outcomes of this study could be useful to food industries seeking low cost biogum.     

Changes in chemical composition of the kew cultivar of pineapple fruit during development

The chemical composition of the Kew cultivar of Indian pineapple (Ananas cosmosus L.) was studied after 65 days (pre-mature), 100 days (early mature), and 150 days (late-mature) from flowering. The fruit was analysed for sugars, amino acids and minerals. Total soluble carbohydrates increased from 6.02 to 9.24%, and protein content decreased from 0.69 to 0.21%, during the fruit-development process. The vitamin C content decreased from 20.4 to 11.1 mg 100 g^?1 edible fruit during development. Fructose, glucose and sucrose together constituted approximately 5.0% (pre-mature), 2.4% (early mature), and 1.2% (late-mature) of fresh weight. The contents of iron, boron and zinc increased during development. The major minerals in the mature fruit were potassium (31.33 mg 100 g^?1), phosphorus (3.13 mg 100 g^?1), calcium (3.92 mg 100 g^?1), sodium (2.63 mg 100 g^?1), iron (3.22 mg 100 g^?1), zinc (0.55 mg 100 g^?l), and copper (0.06 mg 100 g^?1) of fresh sample. The content of most amino acids decreased during development; only aspartic acid showed a considerable increase in the late-mature fruit.     

The effects of sorbates on the ensilage of chopped whole-plant maize and lucerne

The incorporation of (a) sorbic acid (0.18 and 0.90 g kg^?1, fresh weight basis) and potassium sorbate (0.90 g kg^?1) with chopped lucerne, and (b) sorbic acid (0.90 g kg^?1) and potassium sorbate (0.90 g kg^?1) with chopped maize (whole-plant) at the time of ensiling, led to a reduction in the surface spoilage associated with the ensilage of these two forages. Use of sorbic acid (0.90 g kg^?1) and potassium sorbate (0.90 g kg^?1) led to (a) a reduction of volatile nitrogen (VN), higher levels of residual water-soluble carbohydrates (WSC) in lucerne silage and more aerobically stable lucerne silage and (b) a reduction in weight loss, population of yeasts and moulds, and VN, higher levels of WSC in maize silage and more aerobically stable maize silage when compared to the untreated forages or forages treated with sorbic acid and potssium sorbate at 0.045 and 0.18 g kg^?1 (fresh weight basis), respectively.     

Effect of dephosphorylation on bovine casein

Bovine whole casein, α- and β-casein were dephosphorylated by potato acid phosphatase (EC 3.1.3.2); the extents of dephosphorylation were as follows: whole casein 71.6%, α-casein 89.2% and β-casein 73.7%. SDS-PAGE, urea-PAGE, RP-HPLC and ESI-MS demonstrated effects of dephosphorylation on the caseins; α- and β-casein showed both proteolysis and dephosphorylation while whole casein showed only dephosphorylation. Urea-PAGE and ESI-MS confirmed the identities of the individual fractions. ESI-MS established (a) the MW for α- and β-casein as 23 612 and 24 017 kDa, respectively, (b) random removal of 1, 2, 4, 6, 7 and 8 phosphate groups during dephosphorylation of α-casein, (c) random removal of 1, 2, 3, 4 and 5 phosphate groups during dephosphorylation of β-casein and (d) limited dephosphorylation of both α-casein (1 and 2 phosphates) and β-casein (1 phosphate) in the absence of the phosphatase.     

Protein Structural Changes During Preparation and Storage of Surimi

The changes in protein structure associated with the preparation and frozen storage of surimi were investigated. Raw surimi was prepared by repeatedly washing Alaska pollock flesh with chilled water. The product was either slowly frozen or underwent rapid freezing using liquid air; in either case it was then subjected to frozen storage at ‐20 °C for 24 mo. Fourier transform infrared/attenuated total reflectance (FTIR/ATR) spectroscopy showed that during preparation of surimi, the a‐helix content increased with increased number of washing cycles. Differential scanning calorimetry (DSC) revealed a shift in the thermal transition of actin to a higher temperature during surimi preparation. Electrophoresis, FTIR/ATR spectroscopy, and DSC results revealed a loss of myofibrillar proteins from surimi after 3 washing cycles, suggesting that 3 washing cycles were adequate to prepare surimi. Sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE) showed relatively minor changes in protein subunit structure with some loss of the myosin light chains (MLC); myosin heavy chain (MHC), actin, and tropomyosin were found to be relatively stable. Native‐PAGE showed no major changes in surimi after 24 mo storage at ‐20 °C. FTIR/ ATR spectroscopy indicated a significant decrease in a‐helix relative to p‐sheet structure in surimi after 2 y of storage at ‐20 °C. The loss of α‐helical content was more significant in slowly frozen surimi compared with rapid‐frozen surimi samples. DSC results revealed a shift in the thermal transition of actin to lower temperatures during frozen storage of surimi.     

A Device for Monitoring Silage Effluent Produced in Laboratory Silos

A relatively simple device was constructed and employed for monitoring production of effluent from laboratory silos. In experiments in which laboratory silos were filled (.7 kg) with red clover, barley mixture (25.7% dry matter) or with alfalfa (26.0% dry matter), pressures simulated commercial silos. Significant differences in quantities of silage effluent were obtained when the same forage was subjected to different treatments designed to disrupt plant cell membranes before external pressure was applied. The device potentially is useful for investigating effects of various conditions of ensiling on effluent production during silage fermentation.     

Characterization of the produced electrospun fish gelatin nanofiber containing fucoxanthin

Food Science and Biotechnology - This study aims to prepare fish gelatin nanofibers extracted from fish waste by using electrospinning method and its encapsulation with fucoxanthin extracted from...