Preparation Of Protein Hydrolysates Research Articles

An optimized protocol for the preparation and application of acid protease

A protocol is devised for the optimal secretion and recovery of acid (fungal) protease preparation at 400 1 scale. Using UV-exposed, high yielding Rhizopus SMC strain, this protocol comprised of: (a) an optimized production medium (pH 4.3 ± 0.2) containing 3% (w/v) wheat flour, 0.1% (v/v) Tween-80, 0.003% (v/v) corn oil and 0.1 N NaOH-extract (1 h, 90°C) of 3% (w/v) soybean flour and 0.5% (w/v) casein; (b) optimized physical parameters of production, such as a 24-h-old inoculum (5%, v/v), 28 ± 1°C, 300 ± 20 rpm, aeration at the rate of 13 ± 2 m 3 h −1 for the first 16 h and 33 ± 3 m 3 h −1 after 16 h until harvesting (80 ± 10 h); and (c) recovery steps including filtration (600 1 h −1, rate of filtration), precipitation (15°C, 8 h) with 4 vol of denatured spirit, centrifugation (27°C, 1700 rpm, 1800 1 h −1), dehydration under vacuum (740 mm of Hg, 35°C, 20 h) and pulverization through 200 mesh sieve. This procedure afforded an average 70% recovery of acid protease in the form of off white-faintly brown coloured free-flowing powder containing 2000 ± 200 U g −1 activity. The raw material cost was US$ 18 ± 2 MU −1. During storage in moisture-free conditions for 24 months at 4, 27 and 37°C, the protease preparation was found to retain 90, 80 and 75% of its initial activity, respectively. The enzyme was stable in a broad pH range and its optimal activity was at 60°C. These features are desirable in commercial applications of acid protease in (a) degreasing-cum-dehairing of hide for superior leather, (b) digestive aid formulation and (c) the preparation of protein hydrolysates.

Rapid Protein Hydrolysis by Microwave Irradiation Using Heat‐Resistant Teflon‐Pyrex Tubes

AbstractA rapid peptide‐bond hydrolysis by means of microwave irradiation is introduced for the facile preparation of protein hydrolysates used for amino acid analysis. The optimal hydrolysis condition has been determined using several enzymes with known amino acid compositions. The effects of hydrolysis time on the recovery of various labile and hydrophobic amino acids are also exemplified in the microwave heating of standard amino acids. The method has been applied to the complete amino acid analysis with a single nonvolatile solvent of methanesulfonic acid with good recovery of tryptophan and half‐cystine. It provides a radical expedition of protein and peptide hydrolysis via commercial microwave ovens and specially‐designed Teflon‐Pyrex tubes, circumventing the tedious procedures using vacuum‐sealed pyrex lubes heating at 110°C for more than 24 h. This novel type of microwave chemistry associated with rapid peptide‐bond cleavage is of great potential in the automation of the complete process of amino acid analysis starting from the preparation of protein hydrolysates.

Preparation and Characterization of Enzymic Milk Protein Hydrolysates from an Ultrafiltration Reactor

Addition of small amounts of plasma activated the deamination of tryptamine by platelet monoamine oxidase (MAO). At higher concentrations, plasma inhibited the deamination instead. The inhibition was increased with increasing amounts of plasma added. The inhibition was uncompetitive in nature, partially reversed by prior ultrafiltration of the plasma through PM30 membranes and completely reversed by protein precipitation of plasma with perchloric acid. Addition of high amounts of plasma in vitro also inhibited the activity of bovine striatal MAO. The inhibition of striatal deamination of tryptamine by plasma was noncompetitive in nature, completely reversed by ultrafiltration through PM30 membranes and partially reversed by perchloric acid treatment. The inhibition of striatal deamination of serotonin was noncompetitive in nature, not reversed by ultrafiltration but completely reversed by perchloric acid treatment. The pattern of inhibition of platelet or striatal MAO by plasma was different from that induced by addition of bovine serum albumin (BSA). Low concentrations of BSA added in vitro activated the deamination of tryptamine or serotonin by platelet or striatal MAO by decreasing the Km, while higher concentrations also decreased the Vmax. The presence of protein, non-albumin circulating modulators of platelet or striatal MAO in plasma is discussed.

Preparation of a protein hydrolysate from tomato seed meal

Preparation of a protein hydrolysate from tomato seed meal

LITERATURE ABSTRACTS

GENERAL PRINCIPLES: Elasticity of Collagen Casings. M. Branicz GENERAL PRINCIPLES: Rheological Modeling of Cooked Potatoes. D. C. Davis, P. F. McMahan and H. K. Leung GENERAL PRINCIPLES: Investigation into the Interaction of Different Properties in the Course of Sensory Evaluation Tests. II. The Effect of Consistency upon Taste. Gy. Urbányi OBJECTIVE MEASUREMENTS: Determination of the Shelf Life of Food Products. I. Varsányi and L. Somogyi OBJECTIVE MEASUREMENTS: The Influence of the Interaction of Mono‐ and Di‐Glycerides with Milk Proteins on the Rheology and Stability of Food Emulsions. G. Doxastakis and P. Sherman OBJECTIVE MEASUREMENTS: Time‐Temperature Tolerance and Physical‐Chemical Quality Tests for Frozen Red Hake. J. J. Licciardello, E. M. Ravesi, R. C. Lundstrom, K. A. Wilhelm, F. F. Correia and M. G. Allsup OBJECTIVE MEASUREMENTS: The Preparation of Protein Hydrolysate from Defatted Coconut and Soybean Meals II Quality and Sensory Evaluation of Products. Chay B. Pham and R. R. Jel Rosario OBJECTIVE MEASUREMENTS: Factors Affecting the Staling of Madeira Slab Cake. Robin C. E. Guy OBJECTIVE MEASUREMENTS: Solubilisation and Characterisation of Wheat Gluten Proteins: Correlations Between the Amount of Aggregated Proteins and Baking Quality. J. Michael Field, Peter R. Shewry and Benjamin J. Miflin OBJECTIVE MEASUREMENTS: Predicting the Texture of Sausage Containing Soy Protein from Their Emulsifying Capacity and Efficiency. C. Simard, F. Castongne and A. Boudreau OBJECTIVE MEASUREMENTS: Dynamic Mechanical Properties of Milk and Milk Gel. M. Tokita, H. Futakuchi, R. Niki, S. Arima, and K. Hikichi OBJECTIVE MEASUREMENTS: The Secondary Phase of Milk Coagulation. Effect of Calcium, pH and Temperature on Clotting Activity. M. A. Mehaia and M. Cheryan OBJECTIVE MEASUREMENTS: Differential Scanning Calorimetry, Melting Temperature Range, and Viscosity for Oils Presumably Provoking “Toxic Syndrome.” C. Herrera Gomez, J. Martin Cabrera and G. Montes Gallegos RELATIONSHIP TO STRUCTURE: Microstructure of Protein Gels in Relation to Their Rheological Properties. T. Sone, S. Dosako and T. Kimura.

The preparation of protein hydrolysate from defatted coconut and soybean meals.

SummaryProtein hydrolysate prepared from defatted soybean meal and coconut meal using acid hydrolysis under different conditions were analysed and subjected to sensory evaluation. Analysis of amino acid after hydrolysis showed a 10.32% reduction in the soybean product and a 31.93% reduction in coconut product. Chemical analyses showed similarities in pH, viscosity, salt content and reducing sugar between the hydrolysates and the commercial soy sauce sample. Both amino and total nitrogen and acidity were higher in the hydrolysate than the commercial sample.Sensory evaluation showed that hydrolysed soybean products gave better scores in terms of colour, aroma, flavour and general acceptability than coconut products. Addition of soybean to coconut meal resulted in improved hydrolysed product.

The preparation of protein hydrolysate from defatted coconut and soybean meals

SummaryThis study was conducted to determine the effects of temperature, time and concentration of acids on the hydrolysis of coconut and soybean meals. Using 6∼ hydrochloric acid (HCl), the complete hydrolysis of soybean meal was reached after 36 hr at 95°C, while it took only 24 hr to complete the process when 18 N sulphuric acid (H2SO2) was used at the same temperature. Coconut protein exhibited some degree of resistance to hydrolysis. Using 10 N HC1 and 18 N H2SO2 in two separate tests, it took 48 hr to complete hydrolysis at 95°C. Sulphuric acid caused a considerably greater decomposition of amino acids than HCl during longer periods of reaction with high acid concentration and temperature. Flavour development is a function of the free amino acids released which in turn is a function of acid concentration, reaction time and temperature.

Preparation of fish protein hydrolysates

A process for the preparation of fish protein hydrolysates using commercially available proteolytic enzymes is described. Both non-fatty and fatty species of fish have been used as the raw material and the hydrolysates obtained have been assessed in nutritional studies on neonatal animals. Data on the release of nitrogenous substances during the digestion of cod with the enzyme papain are presented, together with amino acid analyses of the various fractions produced. As far as hydrolysates from non-fatty species are concerned there are no technical difficulties in preparing a spray-dried or concentrated product suitable for animal feeding. For hydrolysates from fatty species, however, it is necessary either to remove the oil mechanically or to stabilise it with suitable antioxidants. For the present exercise, hydrolysates were frozen and stored at −30°C until required for the nutritional studies. Before any industrial development is considered, further studies on the drying and storing of hydrolysates from fatty species are necessary.

Continuous Proteolysis with a stabilized stabilized protease. I. Chemical stabilization of an alkaline protease.

Due to the loss of enzymatic activity as a function of time, an alkaline protease, selected for the continuous preparation of protein hydrolysates (J. Boudrant and C. Cheftel, Biotechnol. Bioeng., 18,1735, 1976), was chemically stabilized by a simple treatment with glutaraldehyde. Two fractions, soluble and insoluble, were obtained. The activities of these two fractions were measured with casein and N-benzoyl-L-arginine ethyl ester (BAEE) as a function of glutaraldehyde concentration used. It was noted that the insoluble fraction was practically inactive with the first substrate and that the heat stability of the soluble form was likewise enhanced. Molecular weights of these two forms were unchanged, but the uv-spectrum of the soluble form was modified. From amino acid analysis, it appears that this treatment mainly provokes a decrease in lysine content.

Hyperammonemia accompanying parenteral nutrition in newborn infants

Elevated concentrations of blood NH3 were found in seven infants who were receivingcasein or fibrin hydrolysates intravenously. Hepatic enzymes and/or hepatic histology were abnormal in four of these seven infants. The high concentration of NH3 in the protein hydrolysate preparation may contribute to the hyperammonemia. Elevated concentrations of blood NH3 were found in seven infants who were receivingcasein or fibrin hydrolysates intravenously. Hepatic enzymes and/or hepatic histology were abnormal in four of these seven infants. The high concentration of NH3 in the protein hydrolysate preparation may contribute to the hyperammonemia.

Oil cake meal for preparation of protein hydrolysate

AbstractWith a view to preparing substitutes for liver or other animal protein hydrolysates used in the treatment of protein malnutrition, a process has been developed based on sesame and mustard cakes as the starting materials. The laboratory process has been successfully scaled up to pilot plant production to compute tentative costing schedule. Essentially the process consists in defatting the cake, isolating the protein by peptization and isoelectric precipitation, enzymatically digesting the protein isolate by papain, and concentrating the digest under reduced pressure. The final product is a light brown fluffy powder, rich in almost all the essential amino acids. Growth experiments with rats have indicated that the product is comparable to commercial casein although supplementation with lysine could further enhance its biological value.

Conference on Amino-Acid and Protein Hydrolysates

THE Food Group of the Society of Chemical Industry is arranging a conference on "Amino Acids and Protein Hydrolysates", which will be held in the William everidge Hall, University of London, Senate House, London, W.C.I, during September 28-30. Papers will be presented upon the chemistry, properties, preparation, analysis, industrial applications and nutritive aspects of amino-acids and protein hydrolysates, and it is hoped that visits may be arranged to laboratories engaged upon work in this field. A detailed programme and application forms for registration will be issued in due course; the honorary secretary of the conference is Dr. A. J. Amos, 88 Madeley Road, London, W.5.

Differential Nitrogen Retention from Casein, Lactalbumin, and Soy Protein, and Hydrolysates Therefrom

Summary The various data illustrating different methods for the biological evaluation of the protein lead, generally speaking, to the same conclusions. The evidence clearly shows the superiority of lactalbumin over casein and the superiority of both casein and lactalbumin over soy protein. If a relative value of 100 was assigned to the lactalbumin, the value for the casein would be about 80 and that of the soy protein between 50 and 60. These general relationships have been indicated by published data from time to time, although the magnitude of the differences have been subject to variations depending upon the particular methods used. Reference has been made to the linear relationship between nitrogen balance and absorbed nitrogen wherein variations in the slopes of the curves are of value as a means for determining the relative or absolute merits of the test materials. Such evidence shows that in each instance the original protein is slightly superior to its hydrolysate in respect to maintenance of a positive nitrogen balance. This relationship, however, is not consistently shown by the calculated biological values (table 1).The relatively greater difference between the iso-electric albumin and its hydrolysate may be accounted for by the intermediate step of peptization before hydrolysis. The difference between the peptized lactalbumin and the hydrolysate prepared direct therefrom is not of substantial magnitude. Two significant deductions may be drawn from the data as a whole. First, appropriate preparation of protein hydrolysates may offer a means of extracting unavailable or indigestible protein from sources not recognized as suitable food products. Second, the mere stipulation of a given percentage of protein in foods or feed stuffs is inadequate in describing their protein value. For instance, in using the nitrogen balance data as a basis of interpretation the soy protein has only about 50 per cent the value of the lactalbumin and about 60 per cent the value of casein; the other data are in substantial agreement. From the standpoint of protein conservation and food economy it is seemingly apparent that as a particular protein more nearly approaches the ideal a commensurate reduction in the amount of dietary protein could be made. The physiological aspects of the lower protein intake may also be of importance from the standpoint of health because the data indicate that a large proportion of the nitrogen absorbed from inferior protein is excreted without commensurately contributing to physiological functions. The average survival period of the groups of animals used in these investigations when furnished the nitrogen-free diet following the test period tends to indicate a significant effect of the previous protein intake. The average survival time for the lactalbumin group was about 30 per cent longer than for the soy protein group, and the survival time for the casein group was about 24 per cent longer than for the soy protein group. One may presume that the variations observed are due to an imbalance or deficiency of amino acids, or possibly to an absence of physiologically important linkages in the inferior protein molecule. If evidence should clearly disclose that the former condition is the cause of the differences, the fortification and enhancement of a deficient protein by appropriate synthetic amino acids in proper balance should prove to be of importance from the standpoint of health and economy and conservation of natural food protein.