Properties of cast films of vicilin-rich protein isolates from Phaseolus legumes: Influence of heat curing

Recent advances in mung bean protein: From structure, function to application

With the surge in protein demand, the application of plant proteins has ushered in a new wave of research. Mung bean is a potential source of protein due to its high protein content (20-30 %). The nutrition, structure, function, and application of mung bean protein have always been a focus of attention. In this paper, these highlighted points have been reviewed to explore the potential application value of mung bean protein. Mung bean protein contains a higher content of essential amino acids than soybean protein, which can meet the amino acid values recommended by FAO/WHO for adults. Mung bean protein also can promote human health due to its bioactivity, such as the antioxidant, and anti-cancer activity. Meanwhile, mung bean protein also has well solubility, foaming, emulsification and gelation properties. Therefore, mung bean protein can be used as an antioxidant edible film additive, emulsion-based food, active substance carrier, and meat analogue in the food industry. It is understood there are still relatively few commercial applications of mung bean protein. This paper highlights the potential application of mung bean proteins, and aims to provide a reference for future commercial applications of mung bean proteins.

Protein composition of pulses and their protein isolates from different sources and in different isolation pH values using a reverse phase high performance liquid chromatography method

The objective of this study was to compare the composition of pulse proteins isolated from lentils and green and yellow peas at two isolation pH values (9 and 11) and determine the effect of this variability on protein functionality. Chromatogram peaks obtained from reverse-phase high performance liquid chromatography were identified by isolation of albumin-, vicilin- and legumin-rich fractions for the three pulses. Protein composition was obtained for each isolate and compared against that of the originating pulse flour. Lentil flour showed the highest level of vicilin with a vicilin/legumin ratio of ∼ 2.5, while this ratio was 1.3 and 1.2 for green and yellow pea flour, respectively. Albumin content of yellow pea flour was high (∼36.1 %), which reduced to ∼ 15-19 % in isolated proteins showing a loss in albumins during the isolation. Higher extraction pH increased pea protein yield but led to lower protein solubility with no changes in foaming properties and in-vitro digestibility.

Changes in Properties of Soy Protein Isolate Edible Films Stored at Different Temperatures: Studies on Water and Glycerol Migration

Plasticizers and the water migration of edible protein films during storage can result in changes in film properties, while specific changing processes need to be further explored. In this study, glycerol-plasticized soy protein isolate (SPI) films were stored at 25 °C, 4 °C, and -18 °C for 6 weeks (relative humidity (RH), 40-50%). The glycerol migration was monitored by the glycerol migration rate and differential scanning calorimetry (DSC). Water content, low-field nuclear magnetic resonance (LF-NMR), and thermogravimetric analysis (TGA) were used to analyze the water state. The results showed that significant pores and cracks were observed after storage at 25 °C. The proportion of bound water gradually increased, and the glycerol migration rate also reached 1.3% and 0.7% at 25 °C and 4 °C, respectively. The results proved that increasing the storage temperature accelerated the loss of water and glycerol, and decreased the mechanical properties of the SPI film.

Design of Bioinspired Emulsified Composite European Eel Gelatin and Protein Isolate-Based Food Packaging Film: Thermal, Microstructural, Mechanical, and Biological Features

The study focused on the elaboration and the characterization of blend biofilms based on European eel skin gelatin (ESG) and protein isolate (EPI) and the assessment of European oil (EO) incorporation effect on their properties. Data displayed that the incorporation of EPI and EO to the gelatin formulation decreased the lightness and yellowness of composite and emulsified films, respectively, compared to ESG film. Moreover, ESG films exhibited improved mechanical properties than EPI films. FTIR analysis, all incorporated films with EO at the ratio 1:4 (oil/polymer) revealed similar characteristic bands as in free-oil films. Further, the SEM images of 100% ESG and 100% EPI films showed a smooth and homogenous structure, whereas the cross-section of blend film (at a ratio 50:50) displayed a rougher microstructure. In addition, emulsified film ESG100 revealed a smooth and homogeneous microstructure compared to that prepared using EPI/ESG 50/50 ratio. Furthermore, EPI or EO addition into the ESG matrix enhanced the blend films antioxidant activities.

Pulse proteins: secondary structure, functionality and applications

Pulses are the second most important source of food for humans after cereals. They hold an important position in human nutrition. They are rich source of proteins, complex carbohydrates, essential vitamins, minerals and phytochemicals and are low in lipids. Pulses are also considered the most suitable for preparing protein ingredients (concentrates and isolates) because of their high protein content, wide acceptability and low cost. In addition, pulse proteins exhibit functional properties (foaming and emulsification, water and fat absorption and gelation) as well as nutraceutical/health benefiting-properties which makes them healthier and low cost alternative to conventional protein sources like soy, wheat and animals. Proteins from different pulses (beans, peas, lentils, cowpeas, chickpeas, pigeon peas, etc.) differ in their composition and structure hence for finished product suitability. Therefore, this article aimed to review composition, structure-function relationship and current applications of different pulse proteins in the food industry.

Effects of Soy Lecithin Levels and Microfluidization Conditions on Properties of Fish Gelatin-Based Film Incorporated with Palm Oil

Properties of film-forming dispersion (FFD) and emulsion film incorporated with palm oil containing soy lecithin at 50 % and 75 % (w/w, based on palm oil) and emulsified with different microfluidization pressures (6.89, 13.79 and 20.68 MPa) and pass numbers (2 and 4) were investigated. Microfluidized FFD containing 50 % soy lecithin showed the smaller oil droplet size. The lower water vapor permeability with higher tensile strength and elongation at break were found for films from microfluidized FFD (p < 0.05). Films containing 50 % soy lecithin had higher light transmittance and lower b*- and ΔE*-values than those containing 75 % soy lecithin (p < 0.05). Smooth surface and compact cross-section were observed in films from microfluidized FFD. Film from microfluidized FFD containing 50 % soy lecithin showed higher thermal stability. Thus, the emulsion film with improved properties could be prepared from FFD using 50 % soy lecithin with the aid of microfluidization.

Influence of palm oil and glycerol on properties of fish skin gelatin-based films

Properties of fish skin gelatin film incorporated with palm oil at 50 and 75 % (w/w) as affected by glycerol at 0-30 % (w/w) were investigated. Increases in water vapour permeability and elongation at break along with decrease in tensile strength were noticed when levels of glycerol were increased (p < 0.05). Decrease in L*- and a*-values with coincidental increase in b*- and ΔE*-values were observed in emulsified films when amount of palm oil incorporated increased (p < 0.05). Light transmittance of all films increased as glycerol levels were increased (p < 0.05). FTIR results suggested that the protein-protein interaction in film matrix decreased when palm oil was incorporated. Films added with palm oil had lower glass transition and degradation temperatures than control films. The addition of 75 % palm oil and 10 % glycerol improved water vapour barrier property of fish skin gelatin films without drastic alteration of mechanical properties.

Effect of glycosylation with xylose on the mechanical properties and water solubility of peanut protein films

This study aimed at improving the mechanical properties and water solubility of peanut protein isolate (PPI) films by glycosylating with xylose (X). The modification process of glycosylation was optimized by using response surface methodology (RSM). The effects of pH, temperature and time on degrees of glycosylation (DG), tensile strength (TS), elongation (E), solubility and microstructure of xylose glycosylated PPI films (PPI-XF) were determined. The changes of DG in different conditions indicated that crosslinking should occur between PPI and xylose during the modification. Optimum glycosylation conditions were found to be pH 9.5, 91.5 °C and 95 min. Under these conditions, TS and E values of PPI-XF were 10.37 MPa and 96.47 %, respectively. Due to glycosylation, solubility of PPI-XF decreased from 96.64 to 35.94 % and these films remained intact in water for 24 h. The microstructure of PPI-XF was denser and more compact than the unmodified PPI films. These results suggest that the xylose glycosylated PPI films have potentiality of being used as biodegradable films in food packaging application.

Influence of heat curing on structure and physicochemical properties of phenolic acid loaded proteinaceous electrospun fibers

Effects of heat treatment on structure and physicochemical properties of zein (Ze) and gallic acid loaded zein (Ze-GA) electrospun fiber mats were investigated. The electrospun fiber mats displayed different surface and physicochemical properties after being heat-cured at 150 °C for 24 h, which were closely related to the initial amount of loaded gallic acid. The gallic acid was released from the Ze-GA fiber mats in a constant manner, but heat curing decreased the rate of release. Heat curing remarkably increased the molecular weight of the Ze and Ze-GA electrospun fiber mats. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) analysis of the fiber mats indicated variations in zein protein secondary structure after heat curing. (13)C solid state NMR (SS-NMR) confirmed the presence of a different chemical environment among the fiber mats. The fabrication of heat-cured zein based electrospun fibers in this study may find applications in the food packaging industry.