Enzymes in Protein Modification

Nielsen, Per Henning

doi:10.1002/9781444309935.ch13

Cited by 4 publications

(6 citation statements)

References 55 publications

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“…This result was consistent with the published results. 28 With addition of PAE, two peaks appeared: one peak was located at about pH 4.5, and the other peak's location varied with PAE concentration from pH 5.4 for 3 wt % PAE to pH 6.1 for 10 wt % PAE (Fig. 1).…”

Section: Complexation Interactionmentioning

confidence: 94%

Isoelectric pH of polyamide–epichlorohydrin modified soy protein improved water resistance and adhesion properties

Zhong

Sun

Wang

2006

J of Applied Polymer Sci

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Protein macromolecules derived from plants have been considered as alternative resources for various applications, including adhesives, films, rubbers, and biocomposites. Plant protein polymers are pH sensitive and need to be modified to meet application performance. This study demonstrated interactions between polyamide-epichlorohydrin (PAE) and soy protein as affected by pH and temperature. PAE and soy protein molecules formed reversible ionic complexes at room temperature at a pH range of 4-9. The complexation interactions acted as physical crosslinking, which stabilized the soy protein structure and increased its denaturation temperature and enthalpy. The viscosity of adhesives derived from the interaction of PAE and soy protein was affected significantly by the complexation formation, denaturation, and pH. The complexation interactions improved the adhesion properties of the PAE/modified soy protein. pH also played an important role in the adhesion performance, which was attributed to the pH dependence of the protein conformation and PAE/soy protein complexation interactions.

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Section: Complexation Interactionmentioning

confidence: 94%

Isoelectric pH of polyamide–epichlorohydrin modified soy protein improved water resistance and adhesion properties

Zhong

Sun

Wang

2006

J of Applied Polymer Sci

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“…Hydrolysis reactions were conducted under floating pH conditions. Nevertheless, we measured the pH of some samples after 24 h. The pH always remained within the suitable pH range of Flavourzyme from 5 to 8 (Nielsen, ).…”

Section: Methodsmentioning

confidence: 99%

Factors impeding enzymatic wheat gluten hydrolysis at high solid concentrations

Hardt

Janssen

Boom

et al. 2014

Biotech & Bioengineering

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Enzymatic wheat gluten hydrolysis at high solid concentrations is advantageous from an environmental and economic point of view. However, increased wheat gluten concentrations result in a concentration effect with a decreased hydrolysis rate at constant enzyme-to-substrate ratios and a decreased maximum attainable degree of hydrolysis (DH%). We here identified the underlying factors causing the concentration effect. Wheat gluten was hydrolyzed at solid concentrations from 4.4% to 70%. The decreased hydrolysis rate was present at all solid concentrations and at any time of the reaction. Mass transfer limitations, enzyme inhibition and water activity were shown to not cause this hydrolysis rate limitation up to 50% solids. However, the hydrolysis rate limitation can be, at least partly, explained by a second-order enzyme inactivation process. Furthermore, mass transfer impeded the hydrolysis above 60% solids. Addition of enzyme after 24 h at high solid concentrations scarcely increased the DH%, suggesting that the maximum attainable DH% decreases at high solid concentrations. Reduced enzyme activities caused by low water activities can explain this DH% limitation. Finally, a possible influence of the plastein reaction on the DH% limitation is discussed.

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“…The presence of exoproteases in Flavourzyme ® which cleave at the C‐ or N‐terminal end of hydrophobic amino acid residues led to a reduction in bitterness (O'Sullivan et al ., ). Besides that, the extent of hydrolysis is important as excessive proteolysis reduces the Mw and could create unwanted flavours such as bitterness due to the formation of small peptides with a relatively high content of hydrophobic amino acids (Nielsen, ). The DHs directly influenced the Mw distribution and amino acid composition of hydrolysates (Kristinsson & Rasco, ), whereas different DH indicate different functionality of hydrolysates such as Mw , where low Mw hydrolysates have lower viscosity (Nieto‐Nieto et al ., ; Zhang et al ., ).…”

Section: Introductionmentioning

confidence: 99%

“…Proteins from meat, milk, wheat and soy are commonly used as ingredients in the food industry (Nielsen, ). In this study, meat protein (i.e.…”

Section: Introductionmentioning

confidence: 99%

Effects of enzymatic hydrolysis treatments on the physicochemical properties of beef bone extract using endo‐ and exoproteases

Chiang

Loveday

Hardacre

et al. 2018

Int J of Food Sci Tech

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This study reported the effects of enzymatic hydrolysis treatments on the physiochemical properties of beef bone extract using endo-and exoproteases. Each enzyme hydrolysis kinetics were studied using Michaelis-Menten model, and the ideal E/S ratio obtained for Protamex Ò (P), bromelain (B) and Flavourzyme Ò (F) was found to be 1.10%, 1.60% and 4.70% w/w, respectively. Seven hydrolysates were produced from single (P, B, F), simultaneous (P + F, B + F) and sequential (P > F, B > F) treatments, where bone extract hydrolysed by Flavourzyme Ò exhibited highest DH and proportion of low molecular weight (Mw) peptides (<5000 Da) in single treatment. When Flavourzyme Ò was used with Protamex Ò or bromelain in simultaneous or sequential treatments, no significant differences in Mw distribution, exposed SH content, SS content and viscosity were evident compared with Flavourzyme Ò only. This indicated that without the addition of other enzymes, Flavourzyme Ò was capable of increasing the proportion of low Mw peptides and reduce viscosity.

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Enzymes in Protein Modification

Cited by 4 publications

References 55 publications

Isoelectric pH of polyamide–epichlorohydrin modified soy protein improved water resistance and adhesion properties

Isoelectric pH of polyamide–epichlorohydrin modified soy protein improved water resistance and adhesion properties

Factors impeding enzymatic wheat gluten hydrolysis at high solid concentrations

Effects of enzymatic hydrolysis treatments on the physicochemical properties of beef bone extract using endo‐ and exoproteases

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