Antioxidant capacity of hydrolyzed protein fractions obtained from an under-explored seed protein: Gingerbread plum (Neocarya macrophylla)

Functional, thermal and structural properties of fractionated protein from waste banana peel

Defatted banana peel powder was fractionated using the Osborne method to extract albumin, globulin, prolamin, and glutelin for physicochemical and functional characterization. The total recovery of protein was ∼89.76%. Albumin was the dominant one in terms of yield (62.4%) and protein content (65.15%) among all the fractions. The mean diameter of albumin (635.05 µm) and glutelin (642.62 µm) were significantly smaller than globulin (726.81 µm) and prolamin (986.45 µm). The highest water (1.86 ± 0.12 g/g), oil (1.97 ± 0.12 g/g) holding capacity, and emulsion capacity (59.27 ± 1.25%) were found for the albumin fraction. In contrast, the glutelin fraction showed the highest foaming capacity (19.13 ± 0.41%) and dispersibility (951.55 ± 3.83 g/kg). The denaturation temperature of protein fractions was found in the range of 30.31-82.08 °C. FTIR confirmed low carbohydrates and protein richness of albumin fraction. XRD revealed the crystalline nature of albumin (65%) and the amorphous nature of other fractions (41-45%). The morphology of all fractions was different, which influenced the functional characteristics.

Influence of high-intensity ultrasound on physicochemical and functional properties of a guamuchil Pithecellobium dulce (Roxb.) seed protein isolate

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.