Preparation and characterization of soy protein isolate/SiO₂ nanocomposite films and their walnut oil microcapsules

Abstract

In this study, nano-SiO 2 /soy protein isolate composite film was prepared by casting method. The effects of (adding 0%, 1%, 3%, 5%, 7%, and 9% w/w) nano-SiO 2 on the properties of the resulting blend films were investigated. Results showed that the addition of 5% nano-SiO 2 exhibited good barrier properties.The mechanical properties including tensile strength and elongation at break of the film with 7% nano-SiO 2 is increased by 82.6% and 31.49% correspondingly. Differential scanning calorimetry indicated that the melting temperature of the composite film is increased by 56.6 C compared with the pure film. The wall material modified by nano-SiO 2 (adding 1%, 3%, 5%, 7%, and 9% w/w) was used for encapsulating walnut oil by spray drying. After accelerating oxidation test at 63 C for 12 days, we found that the encapsulation efficiency value of walnut oil microcapsules with 0%, 1%, 3%, 5%, 7%, and 9% nano-SiO 2 decreased by 64.23%, 48%, 21%, 22%, 21.00%, and 31% respectively. The results suggested that the stability of the core material was improved by adding nano-SiO 2 to the wall material.

Incorporation of hydroxytyrosol alkyl esters of different chain length as antioxidant strategy in walnut oil spray-dried microparticles with a sodium alginate outer layer

“…395, p. 133595. https://doi.org/10.1016/j.foodchem.2022.133595 encapsulated Similar values of EE for WO have been reported using SMP (91%) and SMP+tween-80 (91.01%) with an inlet air temperature of 180 ºC and feed atomization pressure of 3 bar, whereas lower EE values were reported for the encapsulation of WO with SMP+maltodextrin (22.5 -56.19%)(Shamaei et al, 2017). The WO encapsulation with a combination of gum values in the range 80 -85%(Yang et al, 2021).FoodChemistry, 2022Chemistry, , vol. 395, p. 133595. https://doi.org/10.1016Chemistry, /j.foodchem.2022…”

“…Currently, encapsulation of oils by spray-drying is used as a strategy to protect unsaturated lipids (Bakry et al, 2016), because it is simple, low-cost, with short drying times, reproducible and easy to scale up (Geranpour, Assadpour, & Jafari, 2020). There are few studies focused on WO encapsulation by spray-drying, where several biopolymers have been used as encapsulating agents, such as maltodextrin + hydroxypropyl methylcellulose (Martínez et al, 2015), gum Arabic + maltodextrin + gelatin (Luna-Guevara, Ochoa-Velasco, Hernández-Carranza, & Guerrero-Beltrán, 2017), skim milk powder (SMP) (Shamaei et al, 2016), SMP + maltodextrin (Shamaei, Seiiedlou, Aghbashlo, Tsotsas, & Kharaghani, 2017), soybean protein isolate + maltodextrin (Zhou et al, 2017a) or isolated soy protein modified with SiO2 nanoparticles (Yang et al, 2021). Capsul ® (as encapsulating agent) and sodium alginate (as outer layer) have been used in this study for WO microencapsulation by spraydrying using a three-fluid nozzle.…”

Development and Characterization of Pickering Emulsion Stabilized by Walnut Protein Isolate Nanoparticles

“…As shown in Figure 1 D, the characteristic peak of WalPI and nano-WalPI at 3313.3 and 3404.5 cm −1 is attributed to stretching vibrations of OH, and that at 2965.4 and 2931.4 cm −1 to stretching vibrations of CH [ 23 ]. The absorption peaks of amide I (1600~1700 cm −1 ) and the amide II bands (1500~1600 cm −1 ) are attributed to the stretching vibrations of C=O and bending vibrations of N-H, respectively [ 13 ]. Additionally, the main absorption peaks for WalPI (nano-WalPI) were from OH bending at 1401 (1389.6) cm −1 , C-N stretching, and N-H bending at 1241 (1236.2) cm −1 .…”

“…While the thickness of the interfacial layer exceeded the critical value, excess nano-WalPI was repelled by the emulsified droplets, causing the PEs to flocculate [ 35 , 36 ]. Furthermore, because the excess nano-WalPI wasn’t uniformly dispersed [ 13 ], the nano-WalPI combined to form insoluble complexes, resulting in the flocculation of the droplet and an increase in the apparent viscosity of the PE. The PEs with nano-WalPI concentrations of 2.0% to 2.5% exhibited shear-thinning behavior at a shear rate of 0.1–10 s −1 and Newtonian fluid behavior at a shear rate of 10–100 s −1 .…”

“…Walnut ( Juglans regia L.) is a great nutritional nut because of its high levels of unsaturated oils, proteins, polyphenols, vitamins, and other nutrients, and it has several potential health benefits, including antioxidant properties, immune regulation, and cholesterol reduction [ 13 , 14 ]. The walnut residue is the byproduct of walnut processing, with a protein content of more than 50% [ 15 ].…”