Extensive Hydrolysate Research Articles

Obtención y aplicaciones de hidrolizados protéicos

A review on the obtention of plant protein hydrolysates for food use has been carried out. First, the components and factors that participate in the hydrolysis are described. Then a description of the different types of hydrolysates is done: limited hydrolysates (between 1% and 10% degree of hydrolysis) that are used to improve functional properties of foods; hydrolysates with variable degree of hydrolysis that are used as flavourings; by last, extensive hydrolysates (degree of hydrolysis above 10%) that are used as protein suplement in the diet or with a defined composition for the treatment of specific illness.

Extensive and Partial Protein Hydrolysate Preterm Formulas: The Effect on Growth Rate, Protein Metabolism Indices, and Plasma Amino Acid Concentrations

ABSTRACTBackgroundThe use of protein hydrolysate preterm formulas is restricted because data on their nutritional adequacy are scarce. The authors evaluated the rate of growth and indices of protein metabolism in low‐birth weight infants fed extensive and partial protein hydrolysate preterm formula followed for 12 weeks.MethodsA total of 61 low‐birth weight infants were assigned randomly to receive extensive protein hydrolysate preterm formula (EH; n = 16), partial protein hydrolysate preterm formula (PH; n = 15), and standard preterm formula (SF; n = 15), or were fed their own mother's fortified breast milk (FBM; n = 15). The infants were investigated at study entry, and at 4, 8, and 12 weeks after study entry.ResultsThere were no differences with respect to growth rate (weight gain, increments in length and head circumference), urea, albumin, prealbumin, transferrin, and plasma amino acid concentrations (except for tyrosine on a single occasion) according to the degree of hydrolysis. There were also no differences between groups fed hydrolyzed formulas and SF. However, several differences were found when EH and PH were compared with FBM. Weight gain from the entry to 12 weeks, serum urea at 12 weeks, and total plasma essential amino acids at 8 weeks were significantly higher in groups fed EH and PH than in those fed FBM. In addition, valine was significantly higher in groups fed PH (P < 0.05) than in the group fed FBM at 8 and 12 weeks, tyrosine was higher in EH and PH in comparison with FBM at 4 weeks, and in PH versus FBM at 12 weeks after study entry.ConclusionsThis study suggests that experimental EH and PH are at least nutritionally equivalent to SFs.

Extensive and Partial Protein Hydrolysate Preterm Formulas: The Effect on Growth Rate, Protein Metabolism Indices, and Plasma Amino Acid Concentrations

The use of protein hydrolysate preterm formulas is restricted because data on their nutritional adequacy are scarce. The authors evaluated the rate of growth and indices of protein metabolism in low-birth weight infants fed extensive and partial protein hydrolysate preterm formula followed for 12 weeks. A total of 61 low-birth weight infants were assigned randomly to receive extensive protein hydrolysate preterm formula (EH: n = 16), partial protein hydrolysate preterm formula (PH: n = 15), and standard preterm formula (SF; n = 15), or were fed their own mother's fortified breast milk (FBM; n = 15). The infants were investigated at study entry, and at 4, 8, and 12 weeks after study entry. There were no differences with respect to growth rate (weight gain, increments in length and head circumference), urea, albumin, prealbumin, transferrin, and plasma amino acid concentrations (except for tyrosine on a single occasion) according to the degree of hydrolysis. There were also no differences between groups fed hydrolyzed formulas and SF. However, several differences were found when EH and PH were compared with FBM. Weight gain from the entry to 12 weeks, serum urea at 12 weeks, and total plasma essential amino acids at 8 weeks were significantly higher in groups fed EH and PH than in those fed FBM. In addition, valine was significantly higher in groups fed PH (P < 0.05) than in the group fed FBM at 8 and 12 weeks, tyrosine was higher in EH and PH in comparison with FBM at 4 weeks, and in PH versus FBM at 12 weeks after study entry. This study suggests that experimental EH and PH are at least nutritionally equivalent to SFs.

Alcalase rapeseed inhibitors: purification and partial characterization.

Extensive rapeseed protein hydrolysate obtained sequentially with Alcalase and Flavourzyme showed inhibitory activity towards Alcalase. Inhibitory activity decreased as the hydrolytic process progressed probably by heat denaturation and/or partial protease degradation. Alcalase rapeseed inhibitors were purified by gel filtration and subsequent ion exchange chromatography. They are composed of peptides of 8.4 and 6.1 kDa linked by interchain disulphide bonds, as observed by reducing SDS-PAGE, with a native molecular weight of 18 kDa. Aminoacid composition of the inhibitors was characterized by the high proportion of methionine (4.2%) and cysteine (4.6%). Alcalase inhibitors were partially resistant to heat treatment; after heating at 70 degrees C for 45 minutes more than 50% of the original inhibitory activity remained in the purified protein but after heating at 90 degrees C for 5 minutes, inhibitory activity decreased very fast to a basal level. The possible relation of these protease inhibitors with the 2S albumin storage proteins is discussed.

The lessons of noninterventional and interventional prospective studies on the development of atopic disease during childhood.

The lessons of noninterventional and interventional prospective studies on the development of atopic disease during childhood.

Enzymatic protein hydrolysates in human nutrition

Protein hydrolysates constitute an alternative to intact proteins and elemental formulas in the development of special formulations designed to provide nutritional support to patients with different needs. The production of extensive protein hydrolysates by sequential action of endopeptidases and exoproteases coupled with the development of post-hydrolysis procedures is considered the most effective way to obtain protein hydrolysates with defined characteristics. This paper reviews the development and use of protein hydrolysates for dietary treatment of patients with phenylketonuria, food allergy and chronic liver failure.

Production of an extensive sunflower protein hydrolysate by sequential hydrolysis with endo- and exo-proteases.

A high quality protein isolate has been obtained from defatted sunflower meal by alkaline extraction and isoelectric precipitation. Protein content was increased from 31.2 % in the defatted flour to 97 % in the protein isolate. The percentages of fiber, soluble sugars, polyphenols and residual lipids in the protein isolate were reduced to more than 90 % with respect to the defatted meal. The protein isolate was used as starting material for the generation of an extensive enzymatic protein hydrolysate. The hydrolysis was carried out in a pH stat using sequentially an endo-protease (Alcalase) and an exo-protease (Flavourzyme). The protein hydrolysate, with a degree of hydrolysis of 50.7 %, was white and non bitter.

Protein quality of chickpea ( Cicer arietinum L.) protein hydrolysates

Chickpea protein isolate (CPI) was used as the starting material in the production of chickpea protein hydrolysates (CPHs). To obtain a highly extensive hydrolysate with a degree of hydrolysis higher than 50%, a sequential utilisation of endoprotease (Alcalase) and exoprotease (Flavourzyme) was necessary. Molecular weight patterns of CPHs were determined by gel filtration chromatography. As a result of the enzymatic activity, differences in the chromatographic pattern of CPHs were observed. Although significant ( P⩽0.05) decreases of Phe and Arg were observed after hydrolysis, adequate amounts of essential amino acids in relation to the reference pattern of FAO (FAO/WHO/ONU, 1985. Energy and requirements. Technical report series No. 724. Geneva) were found. In vitro protein digestibility of CPHs (95%) were similar to that of the starting material (CPI), and TIA was not detected in any case. A high increase of solubility in CPHs, with respect to CPI, was observed, one CPH being totally soluble over a wide pH range (2–10) when the enzymes were added sequentially. Due to their high protein quality and solubility, CPHs might be considered as potential ingredients in the food industry.

Production and characterization of an extensive rapeseed protein hydrolysate

AbstractRapeseed protein isolate has been used as starting material for the generation of an extensive protein hydrolysate. Protein hydrolysis was produced by using sequentially an endopeptidase (Alcalase) and an exopeptidase (Flavourzyme). The final hydrolysate has a 60% degree of hydrolysis and was completely soluble between pH values 2.5 and 7. Molecular weight profile of the protein hydrolysate was characterized by gel filtration chromatography. A reduction in protein size was observed during the hydrolysis process with accumulation of small peptides and free amino acids after Flavourzyme digestion. Amino acid composition of fractions with different molecular weights of the final hydrolysate was analyzed. Some of these fractions, enriched or poor in certain amino acids, could be used for supplementation or treatment of determined clinical syndromes.

Monoclonal and polyclonal antibodies against casein components of cow milk for evaluation of residual antigenic activity in ‘hypoallergenic’ infant formulas

Hydrolysed casein and whey protein formulas have been developed with the aim of preventing sensitization in infants at high risk of cow milk allergy. Subsequently these products have also been used for treatment of children with cow milk allergy. However, severe reactions have occurred in some allergic infants fed with these formulas raising doubts about their absolute safety and suggest the need for developing in vitro techniques for detection of eventual residual allergenic activity in such preparations. Our purpose was to evaluate the usefulness of monoclonal and polyclonal antibodies against casein components (alpha, beta and kappa casein) as reagents for the detection of the residual antigenic activity of casein components in several hydrolysed formulas. The monoclonal and polyclonal antibodies were produced according to standard procedures by immunizing female Balb/c mice with casein fraction (a mixture of alpha, beta and kappa casein). ELISA assays were developed to test the specificity of the antibodies and to detect and evaluate the amount of residual antigenic activity of the casein components in hydrolysed formulas. Use of polyclonal antiserum specific for casein allowed detection of residual antigenic activity of casein components in all partial hydrolysates and in the two extensive whey protein hydrolysates in the amounts ranging from 0.05 to 0.67% of total protein. No such activity was detectable in either the two extensive casein hydrolysates tested or the aminoacid based formula. The polyclonal antiserum proved to be more suitable than monoclonals for detecting residual antigenic activity in the hydrolysates. The monoclonal antibodies were directed against epitopes expressed on different casein components. In this study the ELISA inhibition assay with polyclonal antibodies specific for casein components of cow milk proved to be a sensitive method for estimating residual antigenicity in the hydrolysed formulas commercially available for infants with cow milk allergy suggesting their potential application for the quality control of hypoallergenic infant formulas.

Studies on bovine pancreatic deoxyribonuclease A: II. The effect of different bivalent metals on the specificity of degradation of DNA

The specificity of deoxyribonuclease A has been shown to vary according to the bivalent metal used for activation of the enzyme. Examination of the 5′- and 3′-terminal nucleosides of oligonucleotides released by deoxyribonuclease A from Escherichia coli K12 and calf thymus DNA after partial, intermediate or extensive periods of hydrolysis has shown that changes in specificity of the enzyme also occur with time during the hydrolysis. The change in specificity was observed only when the enzyme was activated by certain bivalent metal ions and the ions have been divided into two groups. With each ion of Group A, which includes Cd 2+, Ca 2+, Ba 2+, Co 2+ and Mg 2+ plus Ca 2+, distribution of terminal nucleosides of oligonucleotides released by deoxyribonuclease at any period of hydrolysis was the same, the specificity of the enzyme thus remaining constant. With each bivalent metal of Group B, Mg 2+, Mn 2+, Ni 2+, Sr 2+ and Zn 2+, the distribution of terminal nucleosides of oligonucleotides released by deoxyribonuclease A when partial and extensive hydrolysates of DNA were compared was different. Knowledge of the nucleoside termini of mono-, di- and trinucleotides alone only gives partial information on specificity. Total hydrolysates or oligonucleotides of various chain length indicated that deoxyribonuclease activated by Mg 2+, Sr 2+ and Ni 2+ and probably all ions of Group B can be used to isolate certain oligonucleotides lacking dA at the 3′ end. This observation may be of use in sequence studies on DNA.