Impact of high-intensity ultrasound on the physicochemical and functional properties of a protein isolate from passion fruit (Passiflora edulis) seeds

Abstract

A protein isolate from passion fruit seeds (PFSPI) obtained by alkaline extraction and isoelectric precipitation was treated with sonication for 15 and 30 min at 40 kHz to evaluate its impact on the physicochemical and functional properties. The PFSPI had a purity of 96.21% protein, with albumins being the main fraction (75.66%). Ultrasound increased the bulk density (ρ) of PFSPI by 13.3% and the formation a more porous structure by a greater separation between particles. Protein solubility of PFSPI in the range of pH 2–12 sonicated for 15 and 30 min, increased on average 5.21 and 9.86%, respectively, in comparison with the control. PFSPI foaming properties were influenced by pH and sonication time, achieving up to 577%, while the minimum gelling concentration was reduced from 4 to 2% at pH 7. Therefore, sonication treatment improved some functional properties of PFSPI for its potential use as a food ingredient.

Modification of the physicochemical, functional, biochemical and structural properties of a soursop seed (Annona muricata L.) protein isolate treated with high-intensity ultrasound

“…The reduction in W a iin sonicated protein isolates is due to structural modification of the proteins, which facilitates the removal of a greater amount of free water during freeze-drying [18] . Reductions in W a by effect of ultrasound also have been reported for protein isolates from fruit passion [16] , jackfruit [15] and guamuchil [18] seed fruits. The W a values of SSPI of this study (0.404–0.502) were below of the limit value (0.660) considered as safe to prevent the microbiological decay in foods [56] .…”

“…The highest augment on the protein content by effect ultrasound was 5.9 %, increasing from 78.3 % (0 W) to 82.9 % (600 W/30 min). On the other hands, reductions of 70.6 % (400 W/30 min) and 69.2 % (600 W/30 min) also were observed for lipids and moisture contents, respectively, with respect to 0 W. The reduction in the moisture content could be due to the structural modification of the proteins because of the ultrasonic cavitation, which promotes easier and greater water removal [16] . The decrease in moisture content by ultrasound could be the cause of a concentrating effect of the protein content in the SSPI [50] .…”

“…Therefore, such pH values were chosen for the preparation of the SSPI by alkaline extraction and isoelectric precipitation. In previous studies, the pH values for protein extraction and isoelectric precipitation from fruit passion [16] , mango [17] , and orange [19] de-oiled seed flours were 12.0 and 4.5, 11.0 and 5.0, and 12.0 and 4.5, respectively, while that the maximal and minimal protein extractions were 49.5 % and 7.8 %, 53.4 % and 6.9 %, and 90.5 % and 30.7 %.

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“…Recent studies with jackfruit [15] , passion fruit [16] , mango [17] , guamuchil [18] , and orange [19] seeds from fruit processing, have been considered as good raw material in the production of protein concentrates or isolates. On the other hand, when the vegetable protein presents deficiencies in its functional or nutritional characteristics, which limits its application as a food ingredient, some physical, chemical, enzymatic treatments or their combination can be applied to improve its quality [20] .…”

Modification of rheological properties of animal and vegetable proteins treated with high‐intensity ultrasound: A review

“…Espinosa‐Murillo et al. (2021) found that the treatment with an ultrasonic bath (40 kHz; 300 W for 15 and 30 min) increased the protein solubility and foaming capacity of protein isolate from fruit passion seeds.…”