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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. [ABSTRACT FROM AUTHOR]

Alternative pretreatments to food materials are necessary to enhance the dehydration process and improve the quality of products. The aim of this study was to evaluate the effect of the ultrasound pretreatments on the dehydration behavior and quality characteristics of dehydrated shrimp. Shrimps were ultrasonicated in a salt solution (10%) at 4°C for 15 and 30 min in an ultrasonic bath (130 W, 40 kHz) and then dehydrated and their kinetics modeled. The ultrasound pretreatments for 15 and 20 min diminished the dehydration time by 15.6% and 12.1%, respectively, in comparison with the control treatments, being the Page model the one that best described the dehydration kinetics. The content of ash significantly increased (p <.05) and the water activity (aw) significantly decreased (p <.05), while some rehydration quality indices also raised in the dehydrated shrimps pretreated with ultrasound in comparison with controls. Ultrasound can potentially be applied for shrimp dehydration, given the advantages in reducing processing time and improving product quality. Practical applications: Shrimp (Litopenaeusvannamei) is a nutritious seafood that is appreciated for its delicious meat, which represents 53% of the world's aquaculture production of crustaceans. Unfortunately, shrimp like many foods is highly perishable; hence, different processing technologies must be applied to improve its useful life. At present, drying is the main applied method in the aquatic product processing industry, but depending of the applied conditions, changes may occur that affect the quality of the product. Pretreatments such as the ultrasound improved the dehydration process and the quality of the dehydrated shrimp. Therefore, such conditions could be used to produce ready‐to‐eat food from shrimp, as is currently demanded by consumers. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ultrasonication induced structural changes of guamuchil protein isolate (GSPI). • The physicochemical and functional properties of GSPI were changed by ultrasonication. • SEM demonstrated that ultrasonication altered the microstructure of GSPI. • Electrophoresis showed that ultrasonication did not change molar masses of GSPI. In this study, the influence of ultrasound on the physicochemical and functional properties of guamuchil seed protein isolate (GSPI) was investigated. The GSPI was prepared by alkaline extraction and isoelectric precipitation method followed by treating with ethanol (95%), from defatted guamuchil seed flour. GSPI suspensions (10%) were sonicated with a probe (20 kHz) at 3 power levels (200 W, 400 W, 600 W) for 15 and 30 min, in addition, to control treatment without ultrasound. Moisture content, water activity, bulk and compact densities and the L*, a* and b* color parameters of the GSPI decreased due to the ultrasound. Glutelin (61.1%) was the main protein fraction in GSPI. Results through Fourier transform infrared and fluorescence spectroscopy showed that ultrasound modified the secondary and tertiary protein structures of GSPI, which increased the surface hydrophobicity, molecular flexibility and in vitro digestibility of GSPI proteins by up to 114.8%, 57.3% and 12.5%, respectively. In addition, maximum reductions of 11.9% in particle size and 55.2% in turbidity of GSPI suspensions, as well as larger and more porous aggregates in GSPI lyophilized powders were observed by ultrasound impact. These structural and physicochemical changes had an improvement of up to 115.5% in solubility, 39.8% in oil absorption capacity, while the increases for emulsifying, foaming, gelling, flow and cohesion properties of GSPI were 87.4%, 74.2%, 40.0%, 44.4%, and 8.9%, respectively. The amelioration of the functional properties of GSPI by ultrasound could represent an alternative for its possible use as a food ingredient in industry. [ABSTRACT FROM AUTHOR]