Effect of Sodium Sulfite, Sodium Dodecyl Sulfate, and Urea on the Molecular Interactions and Properties of Whey Protein Isolate-Based Films

Whey protein coatings and cast films are promising for use as food packaging materials. Ongoing research is endeavoring to reduce their permeability. The intention of this study was to evaluate the effect of the reactive additives sodium sulfite, sodium dodecyl sulfate (SDS), and urea on the oxygen barrier, water vapor barrier, and protein solubility of whey protein cast films. The concentration of the reactive additives was 1 to 20 wt.-%. Dried whey protein cast films were used as substrate materials. The water vapor transmission rate, the oxygen permeability, and the protein solubility were measured. Effective diffusion coefficients and effective sorption coefficients were calculated from the results of the water vapor sorption experiments. The presence of sodium sulfite resulted in an increased number of hydrophobic interactions and hydrogen bonds and a slightly decreased number of disulfide bonds. The oxygen permeability decreased from 68 to 46 cm3 (STP/standard temperature and pressure) 100 μm (m2 d bar)−1 for 1 wt.-% SDS in the whey protein cast film. The water vapor transmission rate decreased from 165 to 44 g 100 μm (m2 d)−1 measured at 50 to 0% r. h. for 20 wt.-% SDS in the whey protein cast film. The reduction in the water vapor transmission rate correlated with the lower effective diffusion coefficient

Integrating Data Science and Earth Science

This open access book presents the results of three years collaboration between earth scientists and data scientists, in developing and applying data science methods for scientific discovery. The book will be highly beneficial for other researchers at senior and graduate level, interested in applying visual data exploration, computational approaches and scientifc workflows

Characterization of Jatropha curcas L. Protein Cast Films with respect to Packaging Relevant Properties

There is increasing research ongoing towards the substitution of petrochemical based plastics by more sustainable raw materials, especially in the field of bioplastics. Proteins of different types such as whey, casein, gelatine, or zein show potential beyond the food and feed industry as, for instance, the application in packaging. Protein based coatings provide different packaging relevant properties such as barrier against permanent gases, certain water vapour barrier, and mechanical resistance. The aim of this study was to explore the potential for packaging applications of proteins from Jatropha curcas L. and to compare the performance with literature data on cast films from whey protein isolate. As a by-product from oil extraction, high amounts of Jatropha meal are obtained requiring a concept for its sustainable utilization. Jatropha seed cake includes up to 40% (w/w) of protein which is currently not utilized. The present study provides new data on the potential of Jatropha protein for packaging applications. It was shown that Jatropha protein cast films show suitable barrier and mechanical properties depending on the extraction and purification method as well as on the plasticiser content. Based on these findings Jatropha proteins own potential to be utilized as coating material for food packaging applications

Inter-correlation among the hydrophilic-lipophilic balance, surfactant system, viscosity, particle size, and stability of candelilla wax-based dispersions

Owing to a decrease in mineral oil resources, it is crucial to develop packaging materials based on renewable resources. Hence, a water vapor-barrier coating is developed as a natural wax-based dispersion. This dispersion should be stable over the storage time. In this study, the physical stability of a wax-based melt dispersion was analyzed (24 h and 21 days after production), and instability phenomena such as agglomeration, coalescence, and flotation were identified. Furthermore, the inter-correlations among the particle size, viscosity of the continuous phase, physical stability, surfactant chemistry, and hydrophilic–lipophilic balance value were characterized. Particle sizes were described by volume/surface mean d3,2, volume moment mean d4,3, and number mean d1,0 diameter, as well as the span of the volume and number distribution. Stability was characterized by the flotation rate, emulsion stability index, and Turbiscan stability index. Coalescence and agglomeration were not observed after the solidification of the wax particles. A significant correlation was observed for the emulsion stability index, with d3,2, and for flotation rate, with d1,0, d4,3, and viscosity as well, with d1,0, d3,2. Surfactants with hydrophilic–lipophilic balance values of 11–13.5 seem to be the most suitable for stabilizing candelilla wax-in-water suspensions. Particles were smaller, and wax suspensions were better stabilized using Tween 20 and Span 20, compared with Tween 80 and Span 80

Influence of process conditions during aqueous protein extraction upon yield from pre-pressed and cold-pressed rapeseed press cake

As rapeseed is the third most important plant oil source worldwide (after palm and soya), vast amounts of residual press cake containing high amounts of valuable protein are generated during industrial de-oiling processes. Because the utilization of rapeseed press cake in feed and food is limited due to antinutritional factors, such as glucosinolates, alternative applications of rapeseed proteins in the non-food area are being investigated to add value to the rapeseed industry. However, a major problem remaining in protein extraction from de-oiled rapeseed residues is low protein solubility, resulting from thermal protein denaturation during industrial pressing. The aim of this study was to enhance protein yields from aqueous protein extraction by investigating the influence of various extraction conditions. Two different rapeseed raw materials were examined: cold-pressed meal (CPM) and pre-pressed meal (PPM). Factors examined were the solid to liquid (s:l) ratio, extraction time, temperature, pH value, concentration of sodium chloride, number of extraction cycles and the employment of protease. Best yields at mild ambient conditions were 52.3% for CPM and 36.7% for PPM, with the NaCl concentration being the most critical factor among the studied parameters. Interestingly, a simple extraction at native pH (5.7–5.8) gave comparable yields to extractions at pH 7–9. Improved yields were obtained under strong-alkaline conditions and by the employment of Protease A-01 with the limitation of protein hydrolysis occurring under these conditions. The best protein-extraction yields obtained from enzyme-assisted processes for CPM and PPM were 59.5% and 60.6%, respectively, for one-step processes and 80.7% and 78.3%, respectively, for three-step processes. The results obtained contribute to improving the sustainability of protein utilization from industrial waste streams. Thus, they support the ongoing effort to add value to the rapeseed industry within a biobased economy

Sonnenblumenproteine - gesund und funktional

The Fraunhofer Institute for Process Engineering and Packaging IVV has developed a technology that can be used to produce a functional sunflower protein preparation. This has a protein content of 60 %, a high sensory quality, a light colour and positive functional properties. Thus, the plant-based, GMO and allergen-free protein is very well suited for the production of baked goods, spreads and the like

Mechanical and Barrier Properties of Potato Protein Isolate-Based Films

Potato protein isolate (PPI) was studied as a source for bio-based polymer films. The objective of this study was the determination of the packaging-relevant properties, including the mechanical properties and barrier performance, of casted potato protein films. Furthermore, the films were analyzed for cross-linking properties depending on the plasticizer concentration, and compared with whey protein isolate (WPI)-based films. Swelling tests and water sorption isotherm measurements were performed to determine the degree of swelling, the degree of cross-linking, and the cross-linking density using the Flory–Rehner approach. The effects of different plasticizer types and contents on compatibility with potato protein were studied. Glycerol was the most compatible plasticizer, as it was the only plasticizer providing flexible standalone films in the investigated concentration range after three weeks of storage. Results indicated that increasing glycerol content led to decreasing cross-linking, which correlated in an inversely proportional manner to the swelling behavior. A correlation between cross-linking and functional properties was also reflected in mechanical and barrier characterization. An increasing number of cross-links resulted in higher tensile strength and Young’s modulus, whereas elongation was unexpectedly not affected. Similarly, barrier performance was significantly improved with increasing cross-linking. The overall superior functional properties of whey protein-based films were mainly ascribed to their higher percentage of cross-links. This was primarily attributed to a lower total cysteine content of PPI (1.6 g/16 g·N) compared to WPI (2.8 g/16 g·N), and the significant lower solubility of potato protein isolate in water at pH 7.0 (48.1%), which was half that of whey protein isolate (96%). Comparing on an identical glycerol level (66.7% (w/w protein)), the performance of potato protein isolate was about 80% that of whey protein isolate regarding cross-linking, as well as mechanical and barrier properties

Ultrasound-Assisted Extraction of Polyphenols from Olive Pomace: Scale Up from Laboratory to Pilot Scenario

Power ultrasound application has been proven to intensify the extraction of biocompounds from plant materials. In this work, the ultrasound-assisted extraction (UAE) of polyphenols from olive pomace (OP) has been studied at three different scales: laboratory (batch, 400 W, 0 barg), medium (continuous, 1000 W, 1.0 barg), and pilot (continuous, 2000 W, 1.0 barg) taking into consideration the influence of technological parameters: extraction time (s), solvent to solid ratio (mL/g), mixture pH, and acoustic parameters: amplitude (µm), intensity (W/cm2), and applied energy (Wh). A central composite design was used to optimize the UAE at laboratory scale (0.2 kg). The optimal conditions were: time: 490 s; ratio: 2.1 mL H2O/g OP; pH: 5.6 at an acoustic amplitude of 46 µm for a maximum extraction yield of 3.6 g GAE/L of extract. At medium scale (2.2 kg) the UAE was carried out using amplitudes from 41 to 57 µm. The effect of the pressure (1.0 barg) on the UAE was positive, in terms of higher extraction yield (2.9 g GAE/L) and faster extraction rates compared to the non-pressurized UAE (2.5 g GAE/L), however, the extraction yield was lower than the one observed at laboratory scale. At pilot scale (120 kg), the UAE involved different ultrasound constellations (booster + sonotrode) to deliver the ultrasound energy at different acoustic intensities from 23 to 57 W/cm2. The acoustic intensity (W/cm2) exerts an important effect on the extraction yield, and should be tailored to each process scale. The highest yield obtained at pilot-scale was 3.0 g GAE/L, and it was 58% higher than the one observed in the conventional extraction without ultrasound assistance (stirring and heating). In all tests, regardless of the scale, higher yields were observed between 80 and 85 °C. The application of this technology at the industrial scale to evaluate if the improvement of the extraction caused by the application of ultrasound could is still important when other operations like centrifugation, ultrafiltration, and reverse osmosis are included in the system and to evaluate its techno-economic feasibility