Physicochemical and Antioxidant Properties of Industrial Hemp Seed Protein Isolate Treated by High-Intensity Ultrasound.

Ultrasound is one of the non-thermal, green, and novel technologies used to functionalize plant proteins. We recently determined the optimum conditions of high-intensity ultrasound (HIUS) treatment for maximum solubility and investigated the functional properties of hemp seed protein isolate (HSPI) under the optimal conditions. In this study, we analyzed changes in primary, secondary, and tertiary structures, physical microstructures, thermal stability, and antioxidant capacity of ultrasound-applied hemp protein isolate (HSPI-HIUS). The free SH group content (+59%) and zeta potential (+25%) increased upon ultrasound treatment. The electrophoretic protein patterns of HSPI showed no significant change after HIUS treatment. The FTIR spectrum revealed the wavenumber shifts in Amid 1 and 2 regions of protein. The denaturation temperature and the ratio of ß-structure increased after sonication. Antioxidant properties of hemp seed protein isolates were increased by 38% by ultrasound treatment. The obtained data in this study showed that HIUS treatment would be promising for improving the functional, physicochemical, and antioxidant properties of HSPI.

Modification of hemp seed protein isolate (Cannabis sativa L.) by high-intensity ultrasound treatment. Part 1: Functional properties.

High-intensity ultrasound (HIUS) is one of the physical methods to modify protein functionality. This study aims to improve the functional properties of hemp seed protein isolate (HSPI) based on the solubility and particle size using the Response Surface Methodology. The acoustic intensity of 37 W/cm2 and protein concentration of 6.9% for 7.8 min were optimum process conditions that increased HSPI solubility (78%). The functional properties of ultrasound treated isolate (HSPI-HIUS) under the optimal conditions were compared with untreated HSPI. The results revealed that the emulsification, oil absorption, and foaming properties of HSPI-HIUS significantly enhanced after HIUS, whereas gelling concentration significantly decreased. Enhanced functional properties in HSPI-HIUS have been associated with structural changes based on surface hydrophobicity, particle size, and fluorescence intensity. This study indicated that HIUS can increase the functionality and prevalence of hemp seed protein isolate in food products.

Improving the Functional Performance of Date Seed Protein Concentrate by High-Intensity Ultrasonic Treatment.

Date kernel is a plant-derived byproduct that has the potential to be converted into a high-value-added food ingredient, such as protein concentrate, in the food industry. Ultrasound, which is an alternative method for improving the functional properties of food proteins, is an effective physical treatment for modifying protein functionality. Solubility is the main criterion that primarily affects other functional properties of protein concentrates, such as emulsification, foaming, and water and oil binding. The aim of this study is to enhance the techno-functional performance of date seed protein concentrate (DSPC) by maximizing the solubility via a high-intensity ultrasound (HIUS) treatment at a fixed frequency of 20 kHz. The effect of ultrasonic homogenization under varying amplitudes and times (amplitude of 40, 60, and 80% for 5, 10, and 15 min, respectively) on the functional properties of the DSPC was investigated by using the response surface methodology (RSM). A face-centered central composite design (FC-CCD) revealed that the optimal process conditions of HIUS were at an amplitude of 80% for 15 min. The physicochemical and functional properties of the ultrasound-applied concentrate (DSPC-US) were determined under the optimum HIUS conditions, and then these properties of DSPC-US were compared to the native DSPC. The results showed that the solubility of all DSPC samples treated by HIUS was significantly (p < 0.05) higher than that of the native DSPC. In addition, emulsion activity/stability, foaming activity/stability, and oil-binding capacity increased after HIUS homogenization treatments, whereas the water-binding capacity decreased. These changes in the techno-functional properties of the DSPC-US were explained by the modification to the physicochemical structure of the DSPC (particle size, zeta potential, SDS-PAGE, SEM, FTIR, DSC, free SH content, surface hydrophobicity, and intrinsic emission). This work revealed that HIUS could be an effective treatment for enhancing the functional properties of date seed protein concentrate.

Effects of various protein- and polysaccharide-based clarification agents on antioxidative compounds and colour of pomegranate juice.

The effects of natural sedimentation and clarification agents [protein-based (albumin, casein and gelatin) and polysaccharide-based (chitosan and xanthan gum)] on total phenolics, hydrolysable tannins, anthocyanins and antioxidant activity of pomegranate juice were investigated. While protein-based agents led to higher reductions in the contents of total phenolics (7.2-17.2%), hydrolysable tannins (16.7-59.5%) and anthocyanins (11.7-23.7%) (p<0.05) than natural sedimentation, polysaccharide-based agents had similar effects on these compounds, like natural sedimentation (p>0.05). The stabilities of ß-punicalagin and α-punicalagin (the major hydrolysable tannins) against clarification were similar. Moreover, antioxidant activities of the samples clarified with polysaccharide-based agents were higher (2.4-26.6%) than those of the protein-based agents. For both high total phenolic, hydrolysable tannin and anthocyanins contents, as well as high antioxidant activity, we suggest that polysaccharide-based agents be used for the clarification of pomegranate juice. In fact, chitosan is especially recommended for this purpose since chitosan (10.3NTU) led to lower turbidity as compared to xanthan gum (20.0 NTU).

Effects of various sulphuring methods and storage temperatures on the physical and chemical quality of dried apricots.

The effects of different sulphuring methods, i.e. sulphuring by "burning the elemental sulphites (BES)," "SO2 gas from liquified SO2 tank (SG)" and "dipping into sodium metabisulphite solution (DSM)" on the colour (brown colour formation and carotenoid degradation) and the loss of SO2 in apricots from Hacihaliloglu and Kabaasi varieties stored at 5, 20 and 30 °C for a year were investigated. There were significant effects of variety, sulphuring method and especially storage at 30 °C on the brown colour formation and loss of SO2 (P<0.05). As storage temperature-time increased, ß-carotene content decreased. Sulphuring methods and variety did not show significant effect on ß-carotene content (P>0.05). The changes in L(*), b(*) and C(*) values were directly associated with ß-carotene content and browning values. The most suitable method for all samples, except for Hacihaliloglu variety stored at 30 °C (BES), is SG, because the samples retained their attractive golden yellow colour during storage.

Clarification and pasteurisation effects on monomeric anthocyanins and percent polymeric colour of black carrot (Daucus carota L.) juice.

Black carrots (BCs) are a rich source of stable anthocyanins (ACNs). The purpose of this study was to evaluate the effects of clarification and pasteurisation on ACNs of black carrot juice (BCJ). Monomeric ACNs, ACN profile and percent polymeric colour were determined during processing of BCJ. While depectinisation and bentonite treatments resulted in 7% and 20% increases in monomeric ACN content of BCJ, respectively, gelatine-kieselsol treatment and pasteurisation resulted in 10% and 3-16% reduction. Percent polymeric colour decreased after clarification, but substantially increased in samples subjected to heat. ACNs of BCJ samples were identified by HPLC-MS. Unclarified BCJ contained cyanidin-3-galactoside-xyloside-glucoside-ferulic acid as the major ACN, followed by cyanidin-3-galactoside-xyloside-glucoside-coumaric acid, and cyanidin-3-galactoside-xyloside-glucoside. After depectinisation, two more ACNs (cyanidin-3-galactoside-xyloside and cyanidin-3-galactoside-xyloside-glucoside-sinapic acid) were also identified. These results indicated that depectinisation and bentonite treatment had positive effect on the colour of BCJ, while gelatin-kieselsol treatment and pasteurisation had negative effect.

Optimization of furfural and 5-hydroxymethylfurfural production from wheat straw by a microwave-assisted process.

Optimization of acid-catalyzed conversion conditions of wheat straw into furfural, 5-hydroxymethylfurfural (HMF), glucose, and xylose was studied by response surface methodology (RSM). A central composite design (CCD) was used to determine the effects of independent variables, including reaction temperature (140-200 °C), residence time (1-41 min), pH (0.1-2.1), and liquid:solid ratio (15-195 mL/g) on furan and sugar production. The surface response analysis revealed that temperature, time and pH had a strong influence on the furfural, HMF, xylose and glucose yield, whereas liquid to solid ratio was found not to be significant. The initial pH of solution was the most important variable in acid-catalyzed conversion of wheat straw to furans. The maximum predicted furfural, HMF, xylose and glucose yields were 66%, 3.4%, 100%, and 65%, respectively. This study demonstrated that the microwave-assisted process was a very effective method for the xylose production from wheat straw by diluted acid catalysis.

Acid-catalyzed conversion of xylose, xylan and straw into furfural by microwave-assisted reaction.

Furfural is a biomass derived-chemical that can be used to replace petrochemicals. In this study, the acid-catalyzed conversion of xylose and xylan to furfural by microwave-assisted reaction was investigated at selected ranges of temperature (140-190°C), time (1-30 min), substrate concentration (1:5-1:200 solid:liquid ratio), and pH (2-0.13). We found that a temperature of 180°C, a solid:liquid ratio of 1:200, a residence time of 20 min, and a pH of 1.12 gave the best furfural yields. The effect of different Brønsted acids on the conversion efficiency of xylose and xylan was also evaluated, with hydrochloric acid being found to be the most effective catalyst. The microwave-assisted process provides highly efficient conversion: furfural yields obtained from wheat straw, triticale straw, and flax shives were 48.4%, 45.7%, and 72.1%, respectively.