Functional Characteristics of Extruded Blends of Potato Flakes and Whey Protein Isolate

Author(s):  
Mariya A. Dushkova ◽  
Nikolay D. Menkov ◽  
Nesho G. Toshkov

The purpose of the present study was to explore the effects of feed moisture and the addition of whey protein isolate on some physicochemical properties of the obtained extrudates from potato flakes. Extrudates were produced using a laboratory single-screw extruder. Conditions during extrusion were: screw speed - 200 rpm; compression ratio - 3:1; extruders temperature zones - 120, 150, 160 °C; diameter of the nozzle - 5 mm. With increasing of feed moisture content and protein level, there was a significant rise of density as well as lowering of expansion of extrudates. As the feed moisture content increased from 13 to 20 percent w.w. the water absorption index (WAI) increased and the water solubility index (WSI) decreased. The feed protein level increased the protein content and decreased WAI. A maximum of WSI was observed at feed moisture content 20 percent w.w. and protein level 18 percent w.w. The extrusion and the protein addition do not affect the equilibrium moisture of the potato flakes extrudates.

2020 ◽  
Vol 26 (8) ◽  
pp. 666-675
Author(s):  
Zahra Moradi

Considering environmental pollution caused by the non-biodegradable polymers used in food packaging, developing and enhancing the properties of biodegradable films seem to be necessary. For this aim, in the present study, kefiran-whey protein isolate bionanocomposite films were prepared and the impact of different concentrations (1, 3 and 5% w/w) of Al2O3 (alumina) nanoparticles on their physical, morphological, thermal and mechanical properties was studied. Based on the obtained results, an increase in the nanoparticles content led to a significant decrease (p < 0.05) in the water vapor permeability, moisture absorption, moisture content, and water solubility. Scanning electron microscope images showed a homogeneous structure, confirming the good dispersion of alumina nanoparticles with smooth surface up to concentration of 3%. In addition, both thermal stability and mechanical properties of the films were improved by the increased concentrations of alumina. The results of X-ray diffraction indicated that the intensity of the crystalline peaks of film increased with the addition of Al2O3 to kefiran-whey protein isolate matrix. By considering all results, the concentration of 3% was proposed as the appropriate concentration of Al2O3 for the nano-reinforcement of kefiran-whey protein isolate bionanocomposites.


Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4278
Author(s):  
Fitriani Fitriani ◽  
Sri Aprilia ◽  
Nasrul Arahman ◽  
Muhammad Roil Bilad ◽  
Hazwani Suhaimi ◽  
...  

Among the main bio-based polymer for food packaging materials, whey protein isolate (WPI) is one of the biopolymers that have excellent film-forming properties and are environmentally friendly. This study was performed to analyse the effect of various concentrations of bio-based nanocrystalline cellulose (NCC) extracted from pineapple crown leaf (PCL) on the properties of whey protein isolate (WPI) films using the solution casting technique. Six WPI films were fabricated with different loadings of NCC from 0 to 10 % w/v. The resulting films were characterised based on their mechanical, physical, chemical, and thermal properties. The results show that NCC loadings increased the thickness of the resulting films. The transparency of the films decreased at higher NCC loadings. The moisture content and moisture absorption of the films decreased with the presence of the NCC, being lower at higher NCC loadings. The water solubility of the films decreased from 92.2% for the pure WPI to 65.5% for the one containing 10 % w/v of NCC. The tensile strength of the films peaked at 7% NCC loading with the value of 5.1 MPa. Conversely, the trend of the elongation at break data was the opposite of the tensile strength. Moreover, the addition of NCC produced a slight effect of NCC in FTIR spectra of the WPI films using principal component analysis. NCC loading enhanced the thermal stability of the WPI films, as shown by an increase in the glass transition temperature at higher NCC loadings. Moreover, the morphology of the films turned rougher and more heterogeneous with small particle aggregates in the presence of the NCC. Overall, the addition of NCC enhanced the water barrier and mechanical properties of the WPI films by incorporating the PCL-based NCC as the filler.


Foods ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1892
Author(s):  
Qiyang Jiao ◽  
Ziyuan Liu ◽  
Baoyun Li ◽  
Bo Tian ◽  
Ning Zhang ◽  
...  

Whey protein isolate nanofibrils (WPNFs) can be used as a novel stabilizer in the Pickering emulsion system to improve the water solubility, stability and bioavailability of lipophilic bioactive ingredients. In this study, conjugated linoleic acid (CLA) and WPNFs were used to prepare a stable Pickering emulsion. We used a transmission electron microscope, low-temperature scanning electron micrographs and other methods to evaluate the micromorphology, surface hydrophobicity and structural units of the obtained WPNFs. Compared with whey protein isolate/CLA Pickering emulsion, the WPNFs/CLA Pickering emulsion has greater ability to remove 2,2-Diphenyl-1-picrylhydrazyl and 2,2′-amino-di(2-ethyl-benzothiazoline sulphonic acid-6) ammonium salt free radicals. Furthermore, the WPNFs/CLA Pickering emulsion has a more stable effect in terms of droplet size and zeta potential over a wider range of ionic strength and temperature conditions. These findings indicate that Pickering emulsion stabilized by WPNFs is more suitable as a carrier of CLA, as it increases the solubility of CLA and has better active applications in biology and food.


Foods ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 705
Author(s):  
Yejun Zhong ◽  
Jincheng Zhao ◽  
Taotao Dai ◽  
Jiangping Ye ◽  
Jianyong Wu ◽  
...  

Protein–polyphenol interactions influence emulsifying properties in both directions. Puerarin (PUE) is an isoflavone that can promote the formation of heat-set gels with whey protein isolate (WPI) through hydrogen bonding. We examined whether PUE improves the emulsifying properties of WPI and the stabilities of the emulsions. We found that forming composites with PUE improves the emulsifying properties of WPI in a concentration-dependent manner. The optimal concentration is 0.5%, which is the highest PUE concentration that can be solubilized in water. The PUE not only decreased the droplet size of the emulsions, but also increased the surface charge by forming composites with the WPI. A 21 day storage test also showed that the maximum PUE concentration improved the emulsion stability the most. A PUE concentration of 0.5% improved the stability of the WPI emulsions against environmental stress, especially thermal treatment. Surface protein loads indicated more protein was adsorbed to the oil droplets, resulting in less interfacial WPI concentration due to an increase in specific surface areas. The use of PUE also decreased the interfacial tension of WPI at the oil–water interface. To conclude, PUE improves the emulsifying activity, storage, and environmental stability of WPI emulsions. This result might be related to the decreased interfacial tension of WPI–PUE composites.


Foods ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1296
Author(s):  
Jéssica Thaís do Prado Silva ◽  
João Vitor Munari Benetti ◽  
Taís Téo de Barros Alexandrino ◽  
Odilio Benedito Garrido Assis ◽  
Jolet de Ruiter ◽  
...  

Whey protein isolate (WPI) can be used effectively to produce food-grade particles for stabilizing Pickering emulsions. In the present study, crosslinking of WPI microgels using organic acids (tannic and citric acids) is proposed to improve their functionality in emulsions containing roasted coffee oil. It was demonstrated that crosslinking of WPI by organic acids reduces the microgels’ size from ≈1850 nm to 185 nm and increases their contact angle compared to conventional WPI microgels, achieving values as high as 60°. This led to the higher physical stability of Pickering emulsions: the higher contact angle and smaller particle size of acid-crosslinked microgels contribute to the formation of a thinner layer of particles on the oil/water (O/W) interface that is located mostly in the water phase, thus forming an effective barrier against droplet coalescence. Particularly, emulsions stabilized by tannic acid-crosslinked WPI microgels presented neither creaming nor sedimentation up to 7 days of storage. The present work demonstrates that the functionality of these crosslinked WPI microgels can be tweaked considerably, which is an asset compared to other food-grade particles that mostly need to be used as such to comply with the clean-label policy. In addition, the applications of these particles for an emulsion are much more diverse as of the starting material.


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