Effect of extrusion process conditions on extrudates enriched with carotenoids encapsulated by different methods using gum arabic and vegetable fat as carriers

Bioactive compounds into extruded foods enhance their nutritional value but they are heat and shear labile and prone to oxidation. This study was aimed to examine the impacts of distinct encapsulation methods on the stability of carotenoids under typical extrusion conditions. The study presents innovative encapsulation methods and investigates the protection efficacy of carotenoids degradation, as well as the effects on the physicochemical characteristics of carotenoid-rich products. Thus, spray drying, spray chilling, and their combination were compared based on their ability to protect carotenoids. Processing temperatures were 110 °C and 140 °C, and shear rates 500 and 2000 1/s. Carotenoid retention was determined, β- and α-carotene retention ranged from 17 to 44 % and 18 to 48 %, respectively. Upon storage at room temperature, the carotenoid content was stable for 15 days, followed by a marked reduction after 30 days. Extrudates enriched microparticles produced by spray chilling and the combined methods exhibited higher carotenoid protection during storage. They also showed better quality attributes, notably bulk density, high water absorption index, color properties, and carotenoid retention. These findings suggest that encapsulation can protect carotenoids during extrusion, and the protection can be tailored to optimize the attributes of the final products.

Preparation of crosslinked starches with enhanced and tunable gel properties by the cooperative crosslinking-extrusion combined modification

Due to its safety and palatability, the citric acid crosslinking modification is an excellent way to modify the properties of starch gels. However, the application of this method is restricted by the low degree of crosslinking of gels produced by this method in the hydrogel system. To produce citric acid-crosslinked starch with improved strength and tunable gel characteristics, a novel ion-esterification cooperative crosslinking-extrusion combined (CCEC) modification approach is presented in this study. The linear and nonlinear rheological characteristics of the samples were measured to evaluate the effectiveness of CCEC modification. Findings disclosed that at 0.1 % strain, the elastic modulus of the CCEC-modified starch (SC-0.5Zn2+, G' = 1522.29 ± 36.31) exhibited a significant rise of 387.27 % as compared to the elastic modulus of citric acid-crosslinked starch (SC, G' = 318.29 ± 11.62). Furthermore, changing the cation concentration allowed for efficient control of the gel's rheological characteristics. The samples were characterized by SEM, FTIR, XRD, and XPS. The CCEC-modified gels had a smaller pore size distribution and a denser honeycomb porous structure. The CCEC modification reaction involves ester bonds and electrostatic attraction. This research is essential to elucidate how coupled physicochemical modification techniques affect the manipulation of starch gel characteristics.

Changes of the main components, physicochemical properties of distiller's grains after extrusion processing with focus on modification mechanism

Distiller's grains (DGs) possessed great potential utilization value due to their rich active ingredients. However, its utilization efficiency was limited by the large amount of lignocellulose components and water-insoluble proteins. In this work, single screw extrusion was applied to modify physicochemical properties of DGs. Results indicated that extruded distiller's grains (EDGs) exhibited the lower crude fiber content (26.01%), the higher soluble fiber (9.07%) and the smaller particle size when compared with those of Control, and subsequently achieving the increased bulk density, swelling capacity and water/oil holding capacity. The crude protein in EDGs decreased slightly, while the total amount of acid hydrolyzed amino acids showed a significant increase. Additionally, the looser, coarser and fragmentary microstructure of EDGs were observed. The main macromolecules in EDGs had been modified distinctly based on thermal analysis, crystallinity and functional groups analyses, while the possible schematic diagram was conducted to better understand the modification mechanism.

Possibility of Alternaria toxins reduction by extrusion processing of whole wheat flour

This study represents the first report about possibility of reduction of Alternaria toxins in wheat using the extrusion process. Effects of extrusion processing parameters - moisture content (w=16, 20, 24g/100g), feeding rate (q=15, 20, 25kg/h), and screw speed (v=300, 390, 480rpm), on reduction rate of tenuazonic acid (TeA), alternariol (AOH) and alternariol monomethyl ether (AME), in whole wheat flour were investigated. Temperature ranged between 111.1 and 160.8°C, while the absolute pressure was from 0.17 to 0.23MPa. The simultaneous influence of w and v was the most important for TeA reduction (p<0.05), while v and q were the most influential for AOH reduction (p<0.01). Level of AME reduction was mostly influenced by w and v (p<0.10). Optimal parameters for reduction of all three Alternaria toxins were as follows: w=24g/100g, q=25kg/h, v=390rpm, with a reduction of 65.6% for TeA, 87.9% for AOH and 94.5% for AME.