The Effects of Hot Air and Microwave Drying on the Structural and Physicochemical Properties of Soluble Dietary Fiber from Sugar Beet Pulp

Normal pressure steaming, high pressure steaming, microwave, and frying are widely used to deactivate enzyme in the oats, but these thermal processing methods may affect the structural and functional properties of soluble dietary fiber, which contribute greatly to the health benefits of oat foods. The objective of this study was to evaluate the effects of four different thermal processing methods on the structural and functional properties of soluble dietary fiber from whole grain oats. The results showed that the thermal processing resulted in changes on nutritional components of whole grain oats. Especially dietary fiber components, the total dietary fiber, insoluble dietary fiber, and soluble dietary fiber content of heat-treated oats were significantly increased ( p < 0.05). Moreover, thermal processing can not only result in an increase in molecular weight and particle size, but also cause molecular aggregation and different functional properties of soluble dietary fiber. High pressure steaming-treated oat soluble dietary fiber displayed significantly higher swelling and emulsifying ( p < 0.05), but microwave-treated oat soluble dietary fiber exhibited the highest glucose, cholesterol, and sodium cholate adsorption capacities. These results might provide basic information to help to better understand the functionality of oat soluble dietary fiber and improve the process efficiency of oat foods with high nutritional qualities.

In this paper, a two-step hot air and microwave drying method was used to dry Porphyra, and the drying process was optimized. Taking the total drying time of Porphyra, the contents of protein and total sugar in dried Porphyra as indexes, the optimal drying process was obtained by using central composite design, model fitting by either quadratic polynomial or neural network, and genetic algorithm optimization. The results showed that the total drying time for sequential hot air drying and microwave drying was shorter than that for sequential microwave drying and hot air drying. In the case of sequential hot air drying and microwave drying, the total drying time required to reduce the moisture content to 0.1 g/g DM was the shortest (62.5±1.4 min), if the hot air drying temperature and time were 65 oC and 1 h, and the subsequent microwave power was 400 W. Comparing the contents of protein and total sugar in dried Porphyra obtained under the optimal process conditions of the two drying methods, the quality of dried Porphyra obtained by sequential hot air drying and microwave drying was better than sequential microwave drying and hot air drying. A highest protein content of 68.82±1.46 mg/g DM was obtained, when the hot air drying temperature and time were 48 oC and 3 h, and the subsequent microwave power was 240 W. Moreover, if the samples were first air dried at 65 oC for 2 h and then microwave processed at 240 W to the end, the total sugar content was the highest (124.72±7.17 mg/g DM). Generally, the sequential hot air drying and microwave drying is suitable for the dehydration of Porphyra in terms of drying time and product quality.

This study investigated the effects of seven processing methods on the structure and functional properties of soluble dietary fiber (SDF) from Tartary buckwheat bran, including microwave radiation, high-pressure steam, Aspergillus niger fermentation, Trichoderma viride fermentation, and combinations of these methods with microwave radiation. The results showed that microwave-assisted Aspergillus niger fermentation microwave-assisted fermentation (MA-S) was the most effective method for improving the structure and functional properties of SDF, significantly increased the SDF content. Scanning electron microscopy (SEM) revealed that MA-S-treated SDF had a typical honeycomb-like porous structure. X-ray diffraction (XRD) analysis showed that MA-S treatment significantly increased the crystallinity of SDF and improved its thermal stability. Functional property analysis revealed that MA-S-treated SDF had excellent water-holding capacity (WHC), oil-holding capacity (OHC), swelling capacity (SC), and glucose adsorption capacity (GAC). Additionally, MA-S-treated SDF had enhanced adsorption capacity for cholesterol, nitrite, and bile salts under simulated gastrointestinal pH conditions. Antioxidant activity measurement showed that MA-S treatment significantly improved the DPPH free radical scavenging activity of SDF. Moreover, different extraction methods resulted in differences in the monosaccharide composition of SDF, with glucose, galactose, xylose, arabinose, and uronic acid being the most significantly affected. This study provides new insights and scientific evidence for the development of functional Tartary buckwheat bran SDF, which has significant implications for its application in functional foods.

Quantification of soluble fibre in feedstuffs for rabbits and evaluation of the interference between the determinations of soluble fibre and intestinal mucin

Successful culture of one cell rabbit embryos into morulae and blastocysts in a defined medium: Effects of energy substrates

Flax stems were subjected to microwave drying at controlled temperatures. The rate of drying was then compared with conventional hot air drying. The product temperature was maintained at 40°C, 60°C and 80°C for both microwave and hot air drying. The moisture content of flax stem was about 70% (wet basis). The microwave drying was conducted in a microwave apparatus which recorded mass, product temperature, incident microwave power, reflected microwave power and inlet/outlet air temperature. The final moisture content for experiment was set to 9% (wet basis). Microwave-convective drying ensured about 30% to 70% reduction of drying time for drying flax straw as compared to hot air drying. Curve fitting with different mathematical models were carried out and all the models were fitted well for both hot air and microwave drying. The tensile strength of flax straw, measured with an Instron apparatus, increased with an increase in the processing temperature of both processes. Hot air dried flax straw showed the greatest tensile strength and modulus of elasticity at processing temperatures of 60°C and 80°C with a significant difference.

Evaluation of carob tree (Ceratonia siliqua L.) pods, through three different drying techniques, and ultrasonic assisted extraction, for presence of bioactives

ABSTRACTThis study evaluated the effect of energy-gathered ultrasound treatment on the antioxidant and physicochemical properties of soluble dietary fiber (SDF) from garlic straw. Results showed ultrasonic power and time play an important role in the antioxidant activity of SDF. The strongest activity of scavenging hydroxyl and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals was obtained at ultrasonic treatment of 100 W for 20 min. SDF modified by ultrasound exhibited improved water holding capacity, oil holding capacity, swelling capacity and cholesterol binding capacity. Ultrasonic-treated SDF had lower viscosity than that of untreated SDF. Furthermore, atomic force microscopy (AFM) measurement showed that ultrasound degraded SDF into fragments with smaller particle size. Ultrasound treatment did not change the primary structure of SDF in the test conditions according to the result determined by FTIR. The overall results indicate that SDF from garlic straw treated by energy-gathered ultrasound has great potential to be used in functional foods.

Drying, shrinkage and rehydration characteristics of kiwifruits during hot air and microwave drying

The potential cholesterol-lowering and prebiotic effects of bamboo shoot dietary fibers and their structural characteristics.

Mixed fermentation of navel orange peel by Trichoderma viride and Aspergillus niger: Effects on the structural and functional properties of soluble dietary fiber

Physicochemical, functional and biological properties of soluble dietary fibers obtained from Rosa roxburghii Tratt pomace using different extraction methods

The structural, physicochemical, and functional characteristics of total dietary fiber (TDF), insoluble dietary fiber (IDF), and soluble dietary fiber (SDF) isolated from potato residues were investigated. Potato dietary fiber consisted of IDF (73.18 g/100 g) and SDF (19.60 g/100 g); the main components were cellulose (42.93%) and pectin (27.82%), while lignin content was the lowest (5.74 g/100 g). The SDF contained much more rhamnose and galacturonic acid, whereas the major monosaccharide in IDF was glucose. The hydration properties of TDF, IDF, and SDF were increased with the increasing of temperature and pH, while negatively related to NaCl concentration. Furthermore, SDF exhibited more porous structure in the surface, thereby exhibiting better glucose absorption ability, α-amylase activity inhibition ratio, and cholesterol absorption ability compared with TDF and IDF. Overall, the TDF, IDF, and SDF from potato residues could be used as new functional additive in food industry according to their nature. Practical applications China is the largest potato producer in the world, most of potatoes are used to extract starch, and about 3 million tons of fresh potato residues are generated every year. While most of them are discarded, resulting in serious environmental pollution. Previous studies mainly focused on the extraction methods and characteristics properties of total dietary fiber (TDF) from potato residues, which indicated that potato TDF might exhibit wide applications in food and health products industry. However, the physicochemical and functional properties of potato dietary fiber affected by environmental conditions, such as temperature, pH, ionic strength, dielectric constant, and types thereof. Therefore, it is important to investigate the above properties of potato dietary fibers in order to make better use of it. As far as we know, the related information is rarely reported. The results of this study could provide some data about structural, physicochemical, and functional characteristics of total dietary fiber (TDF), insoluble dietary fiber (IDF), and soluble dietary fiber (SDF) isolated from potato residues, showing that it could be used as new functional additive in food industry according to the nature.

This study analyzed the drying kinetics of peanut pods employing sun, hot air, and microwave drying techniques, and evaluated their mathematical modeling. The findings demonstrated that sun-drying decreased the moisture content from 26.47% to 8-10% over a duration surpassing 72 hours. Hot air drying at temperatures of 60°C, 80°C, and 100°C, commencing with an initial moisture content of 29.92%, necessitated 810 minutes, 360 minutes, and 660 minutes, respectively. Microwave drying, commencing with an initial moisture content of 23.01%, required 40 minutes, 45 minutes, and 60 minutes at belt velocities of 3 mm/s, 4.9 mm/s, and 6.2 mm/s, respectively, at 300 W. At 400 W, the durations were 24 minutes, 30 minutes, and 40 minutes, respectively. All drying kinetics curves exhibited decreasing rates characteristic of agro-food products. Mathematical modeling analysis identified the Midilli model as the most appropriate, succeeded by the Page, Henderson, and Pabis models, for characterizing moisture loss during the sun, hot air, and belt microwave drying of peanut pods.

This study evaluated the effects of including soluble and insoluble dietary fiber sources in soybean oil-containing diet for broiler chickens on coefficient of apparent ileal digestibility (AID) of amino acids, coefficient of apparent retention (AR) of nutrients, and nitrogen-corrected apparent metabolizable energy (AMEn). A total of 180 broilers were divided into 30 groups and fed 3 diets from day 14 to 21 of age. The diets were corn–soybean meal containing 6.8% soybean oil without or with soybean hulls (SBH) or sugar beet pulp (SBP) at 8.0% as sources of insoluble and soluble fiber, respectively. The SBH and SBP contained 6.0% and 14.7% of soluble dietary fiber and 60.5% and 37.0% of insoluble dietary fiber, respectively. The AID of indispensable amino acids was decreased ( P &lt; 0.05) due to dietary inclusion of SBH, but not of SBP. Dietary SBH and SBP reduced the AR of gross energy (by 14% and 8%, respectively) and AMEn (by 20% and 14%, respectively). Overall, inclusion of SBH or SBP at 8.0% in a corn–soybean meal-based diet for broilers that contains high level of soybean oil might not improve nutrient digestibility. However, SBP has less detrimental effects on nutrient digestibility than SBH.