Superheated Steam Treatment Research Articles

Delayed Effect of Superheated Steam Treatment on Starch Retrogradation of Rice Cake After Storage by Modifying Starch Chain-Length Distribution in Rice Flour.

This study investigated the effects of superheated steam (SS) treatment on the physicochemical properties of rice flour and the subsequent impact on rice cake quality. The SS-180 resulted in higher final viscosity and significantly increased pasting time and the temperature of rice flour (p < 0.05). A significant enhancement in the water holding capacity of rice flour (p < 0.05) was due to the rice starch aggregated in this SS process. SS treatment also led to an increase in the proportion of short chains of amylopectin in rice flour from 30.40% to 37.59%, while a decrease in long chains retarded retrogradation and improved rice cake texture. The hardness of the SS-treated rice cake was lower than that of the untreated one, but the specific volume was increased significantly (p < 0.05). After 7 days of storage, rice cake with SS-180 treatment showed the lowest hardness, namely, the lowest retrograded process. These findings underscore the potential of SS treatment to enhance the physicochemical properties of rice flour and improve rice cake quality.

Dual purpose of superheated steam treatment: Inactivating surface pathogens of pork belly and replacing blanching

Superheated steam (SHS) treatment is increasingly recognised as an emerging thermal sterilisation technology in food processing because of its high energy efficiency, time-saving benefits and minimal quality loss in raw materials. The aim of this study was to examine the efficacy of SHS treatment as a high-temperature pre-treatment approach for eliminating foodborne pathogens on the surface of pork belly and to determine its impact on nutritional quality. The SHS treatment at 180 °C and 25 kg h−1 for 50 s achieved sterilisation rates of 98.15% ± 1.70%, 96.59% ± 1.40% and 91.30% ± 2.14% for Salmonella typhimurium, Listeria monocytogenes and Staphylococcus aureus, respectively, which were three times higher than those achieved by microwave (MIC) sterilisation (700 W, 20 s). Furthermore, SHS-treated pork belly exhibited the highest moisture content and lowest cooking loss, with no significant changes in pressing loss and pH values. Compared with samples treated with MIC and blanching (99 °C ± 1 °C, 2 min), those treated with SHS showed significantly lower TBARS value and protein carbonyl content, with an increasing trend in L∗ values. Meanwhile, SHS treatment not only preserved the tenderness of the pork belly to the greatest extent but also yielded the highest sensory score of 7.81 out of 9. These findings indicate the potential of SHS treatment in producing premium-quality pasteurised pork belly.

Effect of superheated steam treatment on rice starch: study on in vitro digestibility and morphostructural, thermal and functional changes

Effect of superheated steam treatment on rice starch: study on in vitro digestibility and morphostructural, thermal and functional changes

The hygroscopic behavior of surface compressed wood in response to superheated steam treatment at varying steam pressures

Superheated steam treatment has been shown to be an efficient strategy for enhancing the dimensional stability of compressed wood. This study evaluated the hygroscopic behavior of surface compressed (SC) wood subjected to superheated steam treatment (SHTSC wood) at varying steam pressures (0.1 MPa, 0.3 MPa, 0.5 MPa, and 0.7 MPa). As the steam pressure increased, the equilibrium moisture content (EMC) of SHTSC wood showed a gradual decrease throughout the hygroscopic range, indicating improved hygroscopic stability. The reduction in EMC for SC wood was associated with a decrease in polylayer moisture content (Ms) from 0% to 95% RH, while the EMC reduction for SHTSC wood was attributed to the combined effect of diminished monolayer (Mh) and Ms. The superheated steam treatment resulted in a range of chemical alterations in the SHTSC wood, including a decrease in hemicelluloses content and the quantity of sorption sites (–OH, C–O groups). Concurrently, there was a relative augmentation in the content of cellulose and extractives, alongside a heightened degree of lignin cross-linking. Furthermore, the superheated steam treatment also affected the cellular structure of the SHTSC wood, resulting in an increased ratio of macropores to mesopores, as well as the formation of microcracks within the cell wall. These changes became more pronounced as the steam pressure elevated, contributing to the reduced hygroscopic characteristics and improved dimensional stability of SHTSC wood.

Comparative study on physicochemical, nutritional and cooking properties of different pigmented dehusked rice varieties influenced by superheated steam treatment

Superheated steam (SS) treatment has emerged as a pivotal technique for improving cereal quality, specifically rice quality in the present studies. This study investigated the effects of SS treatment on the physicochemical characteristics and cooking attributes of pigmented dehusked rice, focusing on three rice varieties: black rice (BLR), red rice (RR), and brown rice (BR). Employing SS treatment was found to not only preserve the desirable appearance of pigmented dehusked rice but also to significantly reduce its cooking duration and overall hardness. A notable preservation of total phenolic content is observed in BLR, contrasting with a pronounced reduction ranging from 41.96% to 46.38% in RR and 26.13%–48.14% in BR. Flavonoid levels across all rice varieties declined to varying extents, from 1.42% to 8.03% in BLR, 8.20%–16.39% in RR, and 28.61%–46.50% in BR, accompanied by a significant reduction in anthocyanin content. Furthermore, SS treatment substantially elevated the total volatile organic compounds in cooked BLR. This study highlights the nuanced impact of SS treatment across different rice varieties, offering insights into its potential for enhancing the culinary and nutritional value of pigmented cereals.

Effect of superheated steam treatment on enzyme inactivation, morphostructural, physicochemical and digestion properties of sand rice (Agriophyllum squarrosum) flour

The lipase (LA) and peroxidase (POD) activities, as well as morphological structure, physicochemical and digestion properties of sand rice flour (SRF) treated with superheated steam (SS), were investigated. SS treatment at 165 °C completely deactivated LA and resulted in a 98% deactivation of POD activities in SRF. This treatment also intensified gelatinization, induced noticeable color alterations, and decreased pasting viscosities. Furthermore, there was a moderate reduction in crystal structure, lamellar structure, and short-range ordered structure, with a pronounced reduction at temperatures exceeding 170 °C. These alterations significantly impacted SRF digestibility, leading to increased levels of rapidly digestible starch (RDS) and resistant starch (RS), with the highest RS content achieved at 165 °C. The effectiveness of SS treatment depends on temperature, with 165 °C being able to stabilize SRF with moderate changes in color and structure. These findings will provide a scientific foundation for SS applicated in SRF stabilization and modification.

Pre-gelatinization phenomenon and protein structural changes in rice quality modification by superheated steam treatment

This study aimed to investigate the effects of superheated steam treatment (SST) on the physicochemical properties, cooking characteristics, and protein structure of rice. According to the results, SST significantly increased the degree of gelatinization, decreased all pasting viscosities and gelatinization enthalpy of rice. Additionally, SST increased the hardness and viscosity of the rice samples. The taste value of SST rice at 155 °C for 10 s increased from 78.5 to 84. Furthermore, SST led to a reduction in the extraction rate of rice proteins, and their secondary structure became ordered. This study also studied the aggregation behavior of rice proteins. These results provide a new perspective on the effects of SST on rice quality modification, especially on pasting characteristics and taste quality, which will contribute to the promotion of SST as a sterilization and modification method in the fresh instant rice industry.

Surface Modification of AISI H13 Tool Steel via Atmospheric-pressure Plasma Nitriding and Superheated Steam Treatment

Surface Modification of AISI H13 Tool Steel via Atmospheric-pressure Plasma Nitriding and Superheated Steam Treatment

A Comprehensive Study on the Influence of Superheated Steam Treatment on Lipolytic Enzymes, Physicochemical Characteristics, and Volatile Composition of Lightly Milled Rice.

Enzyme inactivation is crucial for enhancing the shelf life of lightly milled rice (LMR), yet the impact of diverse superheated steam (SS) treatment conditions on lipolytic enzyme efficiency, physicochemical properties, and volatile profiles of LMR remains unclear. This study investigated varying SS conditions, employing temperatures of 120 °C, 140 °C, and 160 °C and exposure times of 2, 4, 6, and 8 min. The research aimed to discern the influence of these conditions on enzyme activities, physicochemical characteristics, and quality attributes of LMR. Results indicated a significant rise in the inactivation rate with increased treatment temperature or duration, achieving a notable 70% reduction in enzyme activities at 120 °C for 6 min. Prolonged exposure to higher temperatures also induced pronounced fissures on LMR surfaces. Furthermore, intensive SS treatment led to a noteworthy 5.52% reduction in the relative crystallinity of LMR starch. GC/MS analysis revealed a consequential decrease, ranging from 44.7% to 65.7%, in undesirable odor ketones post-SS treatment. These findings underscore the potential of SS treatment in enhancing the commercial attributes of LMR.

Water uptake of radiata pine wood after microwave and superheated steam treatments: sapwood vs. heartwood

Water uptake of radiata pine wood after microwave and superheated steam treatments: sapwood vs. heartwood

Heat treatment of wheat for improving moisture diffusion and the effects on wheat milling characteristics

Superheated steam (SS), heat moisture (HM), and microwaves (MW) were used as heat treatment methods to improve moisture diffusion in wheat during tempering, shortening the tempering time. Moreover, the effects of heat treatment on wheat milling characteristics were studied. The results showed that SS, HM, and MW can all accelerate moisture migration, shortening the time needed for wheat tempering. Additionally, SS, HM, and MW led to an obvious change in the microstructure and a significant decrease in the hardness of wheat grain. In addition, heat treatment of wheat led to an increase in ash content, a decrease in particle size, and an increase in the damaged starch content of wheat flour. Optimized heat treatment could improve the color and dough rheological properties of wheat flour. Among the three methods, SS and HM treatment had fewer effects on wheat milling characteristics and may be suitable for improving moisture diffusion in wheat.

Superheated steam treatment of soft wheat on the physicochemical properties and structure of wheat starch

AbstractSoft wheat grains were treated with superheated steam (SS) at 165 and 190°C, respectively for 1–5 min to understand the changes in the structures and properties of wheat starch following SS treatment. The damaged starch contents, amylose ratio, gelatinization properties, surface morphology, viscosity, and crystalline structure of the starch in wheat flour were determined. Damaged starch content, amylose ratio, and starch viscosity significantly increased after SS treatment. The onset temperature (To) and peak temperature (Tp) of wheat starch increased with the extending of treatment time, while an opposite variation trend was observed for (Tc − To). Additionally, the gelatinization enthalpy (ΔH) decreased after 3–5 min of SS treatment. Starch aggregation was observed in scanning electron microscopy (SEM) graphs. Compared to traditional heat treatment methods, SS treatment of wheat grains may be preferable for modifying the starch properties of soft wheat since much time and energy could be saved.Practical ApplicationThe physicochemical properties and structure of soft wheat starch significantly affect the quality of cakes made with soft wheat flour. After SS treatment of wheat kernels, the amylose ratio and damaged starch content in wheat starch significantly increased. Moreover, gelatinization properties and starch viscosity of wheat starch were also significantly affected. The changes in physicochemical properties were mainly due to the changes in the structure of starch granules and starch molecules. The above results in the physicochemical properties and structure of starch led to the increase in the viscosity and gas retention capacity of cake batter, which might be the reason why the specific volumes and texture of cakes could be improved after SS treatment of wheat. This research verified SS treatment may be preferable for improving cake quality compared to traditional heat treatment methods, which promotes the application of SS in wheat process engineering.

Impact of Treatment with Superheated Steam on the Structural, Thermal, and Functional Characteristics of Quinoa Starch

AbstractThe objective of the study is to evaluate the impact of treatment with superheated steam on the structural, thermal, and functional characteristics of quinoa starch. The superheated steam treatment is applied to the starch at 130 and 170 °C for 1 and 4 min, then dried at 50 °C and stored. Moisture adsorption isotherms are performed at 25 °C, and data are fitted to the Oswin, GAB, and Peleg models. Structural characterization is done using XRD and FTIR, thermal analysis using DSC, and functional characterization include water absorption capacity (WAC), oil absorption capacity (OAC), and syneresis. The QS170/4 treatment shows a reduction in crystallinity index of up to 48.24%, with the appearance of the amylose‐lipid complex, an increase in initial and final gelatinization temperatures, and a decrease in enthalpy of up to 39.53%. For modified starches, WAC and OAC increase by 9% and 7%, respectively, and syneresis decreases significantly by 17.4%. The results demonstrate the feasibility of modifying quinoa starch with superheated steam treatment, which, unlike other methods, has the advantage of altering the amylose and amylopectin chains in just a few minutes. Thus, the results show a new perspective for the use of superheated steam in starch modification.

Inactivation of E. coli O157:H7, Salmonella enterica, and L. monocytogenes through semi-continuous superheated steam treatment with additional effects of enhancing initial germination rate and salinity tolerance

Superheated steam (SHS) is a powerful technology used to reduce bacteria on food surfaces while causing less damage to the underlying sublayer of food compared to conventional heating treatments. In this study, a semi-continuous SHS system was developed to inactivate foodborne pathogens within 1 s (Escherichia coli O157:H7, Salmonella enterica, and Listeria monocytogenes) on radish seed surfaces and to enhance the seeds’ salinity tolerance, which is vital for adapting to arid and semi-arid regions. The temperature of the SHS was set to 200 °C and 300 °C, with flow rates of 5 m/s and 7 m/s, and treatments were cycled either once or three times. As a result, increased temperature (200 °C–300 °C) and number of treatments (1 time to 3 times) led to a significantly larger microbial reduction on the surface of radish seeds. E. coli O157:H7, S. enterica, and L. monocytogenes were reduced by 4.42, 4.73, and 3.95 log CFU/g (P < 0.05), respectively, after three SHS treatments at 300 °C and 7 m/s. However, due to the ongoing potential for recovery of residual microorganisms, further research involving combinations is essential to enhance the microbicidal effect. Water imbibition showed significantly higher values in the SHS-treated group up to 30 min, indicating faster germination rates in the SHS-treated group (71.3–81.3%) compared to the control group (52.7%) on the second day, indicating a significant enhancement in germination rate. In addition, the salinity resistance of the radish seeds increased after SHS treatment. When moisturized with 0.5% NaCl solution, more radish seeds germinated after treatment with SHS (40%) than controls (22.7%) (P < 0.05). The results of this study, the first to apply semi-continuous SHS to seeds, are expected to serve as a cornerstone for future pilot-scale investigations aiming to implement the system within the seed industry.

Modification of Soft Wheat Protein for Improving Cake Quality by Superheated Steam Treatment of Wheat Grain.

Many varieties of soft wheat in China cannot fully satisfy the requirements of making high-quality cakes due to their undesirable protein properties, which leads to shortages of high-quality soft wheat flour. Therefore, a modification of soft wheat protein is essential for improving the quality of soft wheat and thus improving cake quality. In order to modify the protein properties of soft wheat used for cake production, superheated steam (SS) was used to treat soft wheat grains at 165 °C and 190 °C for 1, 2, 3, 4, and 5 min, respectively, followed by the milling of wheat grains to obtain refined wheat flour. The properties of proteins and cakes were analyzed using refined wheat flour as materials. First, changes in the structures of wheat proteins were analyzed by determining the solubility, molecular weight distribution and secondary structure of proteins in wheat flour. Secondly, changes in the functional properties of proteins were analyzed by determining the foaming properties and emulsifying properties of proteins in wheat flour. Finally, the specific volume and texture of cakes with wheat flour milled from SS-treated wheat were analyzed. At the initial stage of SS treatment, some of the gliadin and glutenin aggregated, and the gluten macro-polymer (GMP) contents increased. This allowed a more stable gluten network to form during dough kneading, leading to an improvement in dough elasticity. In addition, a short time period (1-3 min) of SS treatment improved the emulsifying properties and foaming ability of wheat protein, which helped to improve the specific volume and texture of cakes. Increasing the SS temperature from 165 °C to 190 °C reduced the optimal treatment time needed to improve cake quality from 3 min to 1 min. SS treatment for longer time (>3 min) periods led to severe protein aggregation and a decrease in the foaming ability and emulsifying properties of protein, which led to a deterioration in the cake quality. Thus, SS treatment at 165 °C for 1-3 min and 190 °C for 1 min could be a suitable method of improving the physicochemical properties of soft wheat used to make cakes with high specific volumes and good texture.

How superheated steam treatment modifies the physicochemical, functional, nutritional, and anti-nutritional attributes: A case study on guar bean flour

Guar seed flour (GSF) is a nutritionally rich ingredient that is widely available, but antinutritional factors limit its commercial use. Considering this limitation, the present study investigated the effect of superheated steam (SHS) treatment (120–150 °C, 5–15 min) on the nutritional properties, bioactive compounds, anti-nutritional factors, thermo-pasting and structural characteristics, and in-vitro digestibility of GSF. The SHS treatment influenced the carbohydrate, protein, and fat content and improved the functional properties of GSF. Similarly, an increment in total phenolic content, antioxidant activity, and a decline in total flavonoid content was observed. The maximum reduction of tannin, phytic acid, and saponin was observed in GSF samples treated at 150 °C – 15 min. The diffractogram pattern showed a decrease in crystallinity with increasing SHS temperature and duration, trypsin inhibitor activity was reduced, while the in-vitro digestibility increased. Apart from this, the SHS treatment also influenced the thermo-pasting properties of GSF, which might be due to the intermolecular interactions, cross-linking, and starch-lipid interactions. Industrial relevanceThe SHS treatment provides high energy efficiency and has the potential to be commercialized on an industrial scale in the food industry, despite its popularity in the non-food sector. The findings indicate that SHS treatment under optimal conditions improved GSF's physicochemical, functional, and digestibility properties. Furthermore, the SHS treatment was very effective at reducing anti-nutritional factors. The product developed from SHS-treated GSF has the potential to be a viable alternative for food formulations and will have a positive impact on human health.

Influence of superheated steam treatment on physicochemical, edible, and storage characteristics of highland barley grains

AbstractBackground and ObjectivesThe effects of superheated steam (SS) processing conditions on physicochemical properties and edible qualities of highland barley (HB) grains are still not clear enough. The storage stability of SS treated HB grains is also need to be verified through long‐term storage. Effects of SS treatment on physicochemical, edible and storage properties of HB grains were investigated.FindingsSS processing significantly reduced peroxides and polyphenol oxidase activities. Pasting properties showed that SS treatment resulted in significant increase of viscosity parameters. With improved hardness, gumminess, chewiness, and decreased cooking loss, the cooking and textural qualities were improved by SS processing. Storage properties showed that SS processing inhibited the increase of free fatty acid value, peroxide value and carbonyl value during storage, indicating that the oxidative rancidity of HB grains was retarded. SS treatment also maintained the water hydration properties, pasting properties, and textural properties during 6 months of storage.ConclusionsSS treatment significantly improved the edible and storage properties of HB grains.

Inactivation of Bacillus cereus endospores on black pepper by pulsed superheated steam system

In this study, a superheated steam (SHS) system was constructed to inactivate Bacillus cereus endospores on the surface of black pepper, and continuous and pulsed treatment was applied to compare sporicidal effects. Additionally, inactivation mechanisms were analyzed to investigate the differences between pulsed and continuous SHS treatments. SHS at 250 °C and 300 °C for 1 min achieved more than a 3 log reduction, whereas SHS at 200 °C for 1 min achieved less than 2 log reduction in the number of endospores. In addition, higher microbicidal effects were confirmed with pulsed SHS treatment with a shorter duty ratio. To elucidate the inactivation mechanisms, inner membrane damage (dipicolinic acid release), intracellular enzyme activities, and DNA integrity were measured after 300 °C SHS pulsed or continuous treatments. After pulsed SHS treatment for up to 20 s, intracellular enzymes were inactivated more rapidly than after continuous treatment, and more DPA was released after 40 s of treatment, indicating that enzyme inactivation occurred prior to inner membrane damage, and pulsed treatment accelerated this mode of action. DNA integrity was significantly lower after 60 s of pulsed or continuous treatment; however, there was no difference in between pulsed and continuous treatments. Our results provide fundamental insights for the sterilization of black pepper by SHS treatment in food industries.

The effect of wheat flour treated with superheated steam on the microstructure and rheological behaviors of batter and cake quality

AbstractThe purpose of the current study was to investigate the influence of wheat flour treated with lab‐scale superheated steam on the batter characteristics and cake quality. Superheated steam treatment (SST) significantly decreased the density and viscosity of cake batter, indicating that the treated samples contained more air bubbles in the batter system. This result also was confirmed by a light microscope. Following SST, treated samples exhibited a lower apparent viscosity compared to native samples, decreasing both the consistency index and flow behavior index. Meanwhile, SST increased the storage modulus (G′), while it decreased both the loss modulus (G′′) and loss tangent (tanδ). These changes in the batter properties influenced the quality of the final cake products. After baking the batters, the treated samples produced cakes with less baking loss and higher volume and quality compared to the native samples. The internal texture exhibited higher porosity and cell density, increasing from 22.9% and 50.3 cells/cm2 (untreated flour) to 35.6% and 65.1 cells/cm2 (flour treated at 150 °C for 4 min), respectively. In addition, SST significantly decreased the hardness of the cake, thereby endowing the final products with a softer texture. The results of the present work may be useful for improving the commercial production of high‐quality cakes.Practical applicationsThis research provides a new technique to produce high‐quality cakes. In this work, superheated steam treatment (SST) was found to change the physical characteristics of the cake batter, adding more air bubbles and improving the internal structure of the cake. The results show that SST has great prospects for being incorporated into grain processing methods to improve the quality of the final products. The lab‐scale superheated steam processing technique proposed herein features a shorter processing period compared to conventional thermal processing methods, taking mere minutes, and thereby shortening the overall workflow. This work expands the potential applications of superheated steam technology in the food industry.

Durability Evaluation of Outdoor Scrimbers Fabricated from Superheated Steam-Treated Bamboo Fibrous Mats

With natural texture and high performance, bamboo scrimber is one of the artificial lignocellulosic composites widely used in construction, furniture and other structural applications. However, it is vulnerable to the actions of water, ultraviolet radiation and fungus, which affect its durability, especially in the open. Here, bamboo was treated with superheated steam in an attempt to improve the durability of bamboo scrimbers. The chemical composition, mechanical properties, dimensional stability, aging resistance, decay resistance and anti-mildew properties were investigated at different temperatures (160~200 °C). After superheated steam treatment, the relative contents of holocellulose and α-cellulose in bamboo decreased. The bending strength and short-beam shearing strength slightly decreased as the temperature was raised while the modulus was essentially retained. The aging resistance in terms of thickness swelling rate (≤9.38%) was substantially improved. The decay resistance reached to the level of Grade I and can be dramatically enhanced by elevating temperature. The anti-mildew properties were also improved. To take together, superheated steam treatment remarkably improves the resistance of bamboo scrimbers to water, ultraviolet radiation, rot fungi and mildew with some concomitant reduction in mechanical properties. The results will permit outdoor construction using bamboo scrimbers more resistant to environmental damage.