Appearance and Textural Properties of Sheared Low Concentration Potato Protein Gels—Impact of Drying Method, pH, and Ionic Strength

Abstract

The objective was to prepare sheared gels of potato protein concentrate and evaluate the effect of pH (3, ∼4, ∼7), ionic strength (15 or 200 mM) and protein drying conditions (spray or freeze drying) on the final appearance and rheological characteristics. Heat-set gels 3 % (w/w) at a high ionic strength (200 mM) resulted in an inhomogeneous appearance with presence of clots, while low ionic strength (15 mM) gave homogenous structures. Gels prepared at pH 3 became transparent while preparation above pH 3.0 resulted in high turbidity. Heat treatment and cooling resulted in gelation for all samples except freeze dried powder at pH 3.0. Flow curves during shear from 0.1 to 100 s were fitted by the Herschel-Bulkley model indicating shear thinning behavior for all samples except the freeze dried sample at pH 3 which displayed a Newtonian behavior. Oscillatory measurements after shear indicated viscus behavior (phase angle above 45°) for the spray dried sample at pH 3, and gelled behavior (phase angle above 45°) for the remaining gelled samples. Structure recovery was observed after shear in all samples except at pH 3.0. The data shows potato protein can be used as ingredient in protein beverages.

Comparative Assessment of Thermal Aggregation of Whey, Potato, and Pea Protein under Shear Stress for Microparticulation

“…To our knowledge, there is only one study on heating and shearing potato proteins . Patatin, the main protein of potato protein, is a highly hydrophobic protein.…”

“…To our knowledge, there is only one study on heating and shearing potato proteins. 30 Patatin, the main protein of potato protein, is a highly hydrophobic protein. In contrast to whey proteins and pea proteins, patatin does not contain a disulfide bridge stabilizing the molecule but a free thiol group, rendering it reactive to form disulfide bonds.…”

Comparison of Thermal and High-Pressure Gelation of Potato Protein Isolates

“…However, the type of protein extraction and the extracted protein groups might have a major effect on gelation, as others reported that the gelation of potato protein is poor [ 34 ]. Thermal gelation of potato protein was reported to result in the weakest gel at pH ~5 and stronger gels below and above this pH [ 33 , 35 ]. Information regarding HP induced gelation of plant-based proteins is limited in general, and especially regarding the gelation of fruit and vegetable proteins [ 36 ].…”

Towards potato protein utilisation: insights into separation, functionality and bioactivity of patatin

“…(2017b) have used spray‐ or freeze‐dried potato protein powder to prepare sheared gels and assessed the impacts of pH, ionic strength and drying conditions of the protein on the final appearance and rheological characteristics of the resultant gel. The results indicated that high ionic strength led to a heterogeneous gel‐structure, the low pH contributed to a transparent solution and spray‐drying resulted in stronger protein interactions during gelation (Schmidt et al ., 2017b). The aggregation behaviour and mechanism of patatin were investigated by Pots et al .…”

“…Potato proteins can be categorised into three major groups, including patatin, protease inhibitors and high molecular weight (MW) proteins with relative contents of ~40%, ~50% and ~10% respectively (Pots et al ., 1999a). It has been well documented that patatin possesses good functional properties, including solubility, gel‐forming, foaming and emulsifying properties (Ralet & Guéguen, ; Waglay & Karboune, ; Schmidt et al ., 2017b, ). In addition, it possesses diverse bioactivity, including antioxidant, angiotensin I‐converting enzyme (ACE)‐inhibitory, renin‐inhibitory, lipid acyl hydrolase (LAH) and anticancer activities (Liu et al ., ; Sun et al ., ; Fu et al ., ).…”