Sorption isotherms and glass transition temperatures of fish protein hydrolysates with different degrees of hydrolysis

Jardim, D. C. P.; Cândido, Lys Mary Bileski; Netto, Flávia Maria

doi:10.1080/10942919909524607

Cited by 9 publications

(4 citation statements)

References 13 publications

(19 reference statements)

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“…It should be noted that the sorption isotherms were determined using the freeze‐dried samples, so the water contents are not exactly equal to the water contents during hydrolysis. The sorption isotherms are in line with other studies regarding native wheat gluten, (e.g., Viollaz and Rovedo, ) and similar to other protein hydrolysates (Chiang et al, ; Jardim et al, ). Figure b illustrates that an increase in DH% is only possible with a reduction in a w .…”

Section: Discussionsupporting

confidence: 90%

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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Section: Discussionsupporting

confidence: 90%

Factors impeding enzymatic wheat gluten hydrolysis at high solid concentrations

Hardt

Janssen

Boom

et al. 2014

Biotech & Bioengineering

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“…T g diminished with increasing moisture content, showing values between 1 and 55 °C for moisture values between 17 and 6 g water/100 g solids. However, the increase in degree of hydrolysis of the hydrolysates was not refl ected in a decrease in T g (Jardim et al 1999). …”

Section: Glass Transition In Fi Sh Meatmentioning

confidence: 99%

Differential Scanning Calorimetry

Schubring

2009

Fishery Products

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Differential scanning calorimetry (DSC) is a well-established measuring method that is used on a large scale in different areas of research, development, and quality inspection and testing. Thermal effects can be quickly identifi ed and the relevant temperature and the characteristic caloric values determined using substance quantities in the mgmilligram range. Measurement values obtained by DSC allow heat capacity, heat of transition kinetic data, purity and glass transition to be determined. DSC curves serve to identify substances (Höhne et al. 1996). When a material undergoes a change in physical state such as melting or transition from one crystalline form to another, or when a material reacts chemically, heat is either absorbed or liberated. According to Lund (1983), DSC offers a tremendous potential for studying physicochemical changes that occur in foods. During the 1980s, its use in food research became apparent.DSC is characterised by its usefulness for analysing phase changes. Reactions that can lead to such phase changes are crystallisation of water (melting and freezing), evaporation of water and certain chemical reactions, for example protein denaturation. In DSC the temperature of the sample and reference are maintained the same and amount of heat required to achieve this is recorded. The DSC curve is a plot of heat fl ow against temperature. Consequently, the enthalpy change involved in the reaction can be determined from the area under the curve of heat-fl ow versus time. Material of known enthalpy can be used to calibrate the equipment. For samples containing water, evaporation is prevented using sealed containers. For examining frozen water in foods, results that are more reproducible are obtained while thawing frozen products than during cooling and freezing of products, because the variable phenomenon of super-cooling occurs during freezing. For proteins, the temperature corresponding to the maximum peak height is often used as an indication of the denaturation temperature, and the width of the peak as a measure of the complexity of the denaturation reaction. Using these assumptions, it is possible to observe how the denaturation temperature is affected by the changes in pH or the presence of other components, and the variation in enthalpy with denaturation temperature. As a protein becomes more denatured, the size of the peak should decrease. Phase changes in these both main components of the fi sh fl esh (water and protein) are subject of DSC investigation in this special fi eld. DSC has emerged 173 Fishery Products: Quality, safety and authenticity Edited by Hartmut Rehbein and Jörg Oehlenschläger

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“…Equilibrium moisture contents were determined by drying at 105 • C to constant weight. 26 Solubility Solubility S was determined by the method of Morr et al 27 in a 10 g l −1 protein solution (N × 6.25), as a function of pH or NaCl concentration.…”

Section: Water-sorption Isothermsmentioning

confidence: 99%

Enzymatic hydrolysis of Nile tilapia (Oreochromus niloticus) myofibrillar proteins: effects on nutritional and hydrophilic properties

Cândido

Sgarbieri

2003

J Sci Food Agric

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Protein concentrate (PC) was prepared from eviscerated and mechanically deboned fish. The pulp was washed sequentially with 0.05 M NaCl and 4 g l −1 NaHCO 3 solutions, with cold ethanol and then with hot (50 • C) ethanol. Subsequently, it was dried (40 • C) and ground to 60 mesh. Enzyme (Flavourzime  ) hydrolysates were prepared with a degree of hydrolysis (DH) ranging from 3.5 to 45%. The PC was characterized for proximate composition, amino acid profile, physical and functional properties. The influence of DH on functional and nutritional properties was evaluated. Hygroscopicity increased in all hydrolysates for environmental relative humidities above 40% and solubility increased rapidly for DH above 7%. Water retention, water absorption and oil absorption all decreased as a function of DH. The pH (3 to 9) influenced the water and oil absorption of the hydrolysate with 7% DH. A pH near the isoelectric point tends to decrease water absorption but increase oil absorption capacity. The insoluble fraction (IF) of the hydrolysates presented a better amino acid profile than the soluble fraction (SF). The nutritional indexes determined for the IF did not differ from the total hydrolysate, but they were consistently higher than those for the SF.

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Sorption isotherms and glass transition temperatures of fish protein hydrolysates with different degrees of hydrolysis

Cited by 9 publications

References 13 publications

Factors impeding enzymatic wheat gluten hydrolysis at high solid concentrations

Factors impeding enzymatic wheat gluten hydrolysis at high solid concentrations

Differential Scanning Calorimetry

Enzymatic hydrolysis of Nile tilapia (Oreochromus niloticus) myofibrillar proteins: effects on nutritional and hydrophilic properties

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