Effect of superheated steam treatment on quality characteristics of whole wheat flour and storage stability of semi-dried whole wheat noodle

Heat-moisture treatment can modulate all-purpose wheat flour for short dough biscuit making: Evidences and mechanism

In view of the merits of all-purpose wheat flour (APWF) to soft wheat flour (SWF) in cost and protein supply, the feasibility of heat-moisture treatment (HMT, 19% moisture for 1 h at 60, 80 and 100 °C, respectively) to modify APWF as a substitute SWF in making short dough biscuits was explored. For underlying mechanisms, on the one hand, HMT reduced the hydration capacity of damaged starch particles by coating them with denatured proteins. On the other hand, HMT at 80 °C and 100 °C significantly denatured gluten proteins to form protein aggregates, highly weakening the gluten network in dough. These two aspects jointly conferred APWF dough with higher deformability and therefore significantly improved the qualities of biscuits. Moreover, the qualities of biscuits from APWF upon HMT-100 °C were largely comparable to that from SWF, even higher values were concluded in spread ratio, volume, specific volume and consumer acceptance.

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.

Technological and textural properties of gluten-free quinoa-based pasta (Chenopodium quinoa Wild)

Quinoa (Chenopodium quinoa Willd.) is an Andean grain with a perfect nutritional composition that, by diversifying its transformation, becomes an attractive alternative for consumers looking for a high-quality, healthy diet with a source of vegetable proteins. The objective of this work was to elaborate and evaluate the technological and textural properties of quinoa paste in its entirety through the Star-Shaped Composite Central Design (CCD) of 5 process variables: Water Temperature (°C), Water Quality (ml), Mixing Time (min), Drying Temperature (°C), and Drying Time (min), with 5 levels each. At the same time, the yield and good cooking quality were studied to optimize the process. In the model of the equation for the cooking time response, a negative and significant influence of drying temperature was shown. On the other hand, for cooking loss, dough gain, a* and b* values, and texture had high values if the drying time was increased. On the contrary, the L-value decreases, which is positively significant. Meanwhile, the swelling index was only significantly positive within the technological properties. In addition, it was found that the optimal conditions for producing quality pasta were 25 °C: 1150 ml: 30 min: 70 °C and 80 min, respectively, with a desirability of 0.883. When the pasta was prepared with quinoa, the cooking time was 7 min, the cooking loss was 2.46 g/g, the mass gain was 23.6 g/g, the cooking yield was 7.99%, the swelling index was 2.9%, water absorption was 135%, and protein was 12.71 g and 0. 21 Pa in texture, these results being consistent with cited research. Likewise, the whiteness was 51.97 for the values a* 2.41 and b* 12.45; all this analysis is reflected in the final yield of the process at 78%. In conclusion, the results indicated that, by optimizing the conditions in the production of gluten-free quinoa pasta, it is possible to obtain a gluten-free product with high added value, excellent cooking quality, adequate technological properties, texture, and color acceptable to the consumer.

Physicochemical, Quality and Flavor Characteristics of Starch Noodles with Auricularia cornea var. Li. Powder

Auricularia cornea var. Li., as an edible mushroom rich in various nutrients, could be widely used in noodle food. This study aimed to investigate the effect of Auricularia cornea var. Li. (AU) powder on the gel properties, structure and quality of starch noodles. Taking the sample without adding AU powder as a control, the addition of AU powder enhanced the peak viscosity, trough viscosity, final viscosity, breakdown, setback, peak time, gelatinization temperature, G' (storage modulus) and G'' (loss modulus). Meanwhile, the incorporation of AU powder significantly enhanced the stability of the starch gel structure and contributed to a more ordered microstructure also promoting the short-term aging of starch paste. In vitro digestion results displayed lower rapid digestibility (21.68%) but higher resistant starch content (26.58%) with the addition of AU powder and increased breaking rate, cooking loss, swelling index and a* and b* values. However, it decreased dry matter content and L*, particularly the reducing sugar content significantly increased to 4.01% (p < 0.05), and the total amino acid content rose to 349.91 mg/g. The GC-IMS library identified 51 VOCs, and the OPLS-DA model classified 18 VOCs (VIP > 1). Overall, the findings indicate that starch noodles with the addition of AU powder may provide greater nutritional quality, gel stability and starch antidigestibility.

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.

Effect of a Bacterial Laccase on the Quality and Micro-Structure of Whole Wheat Bread

The gluten protein content in whole-wheat flour is low, which affects the elasticity and viscosity of the dough. Enzymatic modification of the protein may result in a network that mimics gluten, which plays an important role in the processing of whole-wheat foods. In this study, the effects of Halomonas alkaliantartica laccase (LacHa) on the quality parameters of whole-wheat bread were investigated. The optimum dosage of LacHa was 4 U/100 g of whole-wheat flour. At this dosage, whole-wheat bread exhibited the best specific volume and optimum texture parameters. Laccase also extended the storage duration of whole-wheat bread. We analyzed the micro-structure of the dough to determine its gluten-free protein extractable rate and free sulfhydryl group content, and verify that LacHa mediates cross-linking of gluten-free proteins. The results demonstrated that the cross-linking of gluten-free protein by LacHa improves the texture of whole-wheat bread. As a flour improver, LacHa has great developmental and application potential in baked-food production.

Effect of sourdough on the quality of whole wheat fresh noodles fermented with exopolysaccharide lactic acid bacteria

In this study, the impact of exopolysaccharides (EPS)-positive strain Weissella cibaria (W. cibaria) fermented sourdough on the quality of whole wheat fresh noodles (WWNs) and its improvement mechanisms were studied. The optimal fermentation conditions were found to be 30% sucrose content, fermented at 25 °C for 12 h, which yielded the highest EPS, 28.06 g/kg, in the W. cibaria fermented sourdough with sucrose (DW+). During storage, the sourdough reduced polyphenol oxidase activities and delayed the browning rate of noodles. The DW+ increased the hardness by 11.98% from 2184.99 to 2446.83 g, and the adhesiveness increased by 19.60%, i.e., from 72.01 to 86.13 g∙s of the noodles. The EPS mitigated acidification of sourdough, prevented the disaggregation of glutenin macropolymers (GMP), and increased sourdough elastic modulus. In addition, scanning electron microscope and confocal laser scanning microscopy of noodles containing EPS sourdough also demonstrated the uniform distribution of gluten proteins. The starch granules were also closely embedded in the gluten network. Thus, the present work indicated that the EPS produced sourdough delayed browning and improved the WWNs texture, indicating its potential to enhance the quality of whole grain noodles.

Three thermal treated methods improve physicochemical and functional properties of wheat bran-germ and the bran-germ containing products

BACKGROUND

To fully investigate the effect of different stabilization methods on WBG in the same environment, we studied the effect of microwaving, baking, and extrusion on the nutritional, physicochemical, and processability properties of WBG and whole wheat bran-germ noodle (WBGN). Principal component analysis was used to comprehensively evaluate the qualities of WBG and WBGN. Machine learning-based research was conducted to predict the quality of WBGN based on the features of WBG.

RESULTS

The results showed that three methods improved antioxidant ability, bound flavonoids, bound and total phenolics, and the processing properties in WBG (P < 0.05). Extruded-WBG showed a lower polyphenol oxidase activity, lipase activity (35.02 ± 2.02 U and 20.29 ± 0.47 mg g^-1 ) and particle size (54.08 ± 0.38 μm), and higher water hold capacity (2.60 ± 0.68%) and bound phenolic levels. The enhanced quantity of bound polyphenols had a major role in the increased antioxidant potential of WBGN. Extruded-WBGN showed higher antioxidant ability for 2,2-diphenyl-1-picrylhydrazyl (171.28 ± 3.16 μmol Trolox eq kg^-1 ). The extruded-WBGN had high concentrations of WBG aroma compounds, and low contents of bitterness and raw bran-germ flavor compounds. Next, the enzymatic activity, powder properties, color, and antioxidant capacity of WBG were further utilized to predict the polyphenolic, flavonoids, flavor compounds, and antioxidant capacities of WBGN, where the R² value of the model exceeded 0.90. The best comprehensive quality modification method of the WBG and WBGN was extrusion, followed by baking and microwaving.

CONCLUSION

The present study shows that extrusion is a promising way to improve WBG into a nutritious and flavorful cereal food ingredient. © 2023 Society of Chemical Industry.

Quality Characteristics of Noodles Produced Using Steam-Treated Dough Prepared with Psyllium Husk and Soaked-and-Dried Soybean

We analyzed the quality characteristics of wheat-free, gluten-free dough, steam-treated dough, and cooked noodles. Dough was prepared from soaked-and-dried soybean (SDS) powder amended with 10%, 25%, or 40% psyllium husk; the SDS was prepared by soaking soybeans for 12 h at room temperature and hot air drying at 60°C for 24 h. Dough was then steam-treated at 120°C for 5, 10, or 15 min and subsequently formed into noodles. Dough and noodle can be made using SDS powder and psyllium husk powder, but it is difficult to maintain noodle shape after cooking without steam treatment. Steam treatment improved the texture of the dough, enabling noodle production. The hardness, gumminess, springiness, cohesiveness, and chewiness of the steam-treated dough were improved compared to nonsteamed dough, yielding a texture similar to wheat flour dough. Moreover, the dough cross-section became denser after steam treatment. As the cooking time increased, the hardness, gumminess, cohesiveness, and chewiness of cooked noodles decreased, and the springiness of cooked noodles increased by increasing of water absorption rate; overall, their form was maintained. Therefore, steam-treated psyllium husk-containing dough enables noodle production without the addition of gluten.

Sensory, structural breakdown, microstructure, salt release properties, and shelf life of salt-coated air-dried yellow alkaline noodles

Salt reduction in food has been employed to improve public health. The effects of salt coatings on sodium content, sensory properties, structural breakdown, microstructure, salt release properties, and shelf life of yellow alkaline noodles (YAN) were evaluated. 15 g/dL resistant starch HYLON™ VII (HC) or 5% (v/v) Semperfresh™ (SC) with 10, 20, and 30 g/dL sodium chloride (NaCl) were used. HC-Na30 and SC-Na30 had the highest sodium content and came closest to commercial YAN in taste and saltiness perception. Structural improvement was demonstrated with HC-Na10 and SC-Na10 as both noodles required maximum work to be broken down. Moreover, SEM micrographs of these noodles showed a more compact and dense appearance with increased continuity of the matrix and fewer voids and hollows. However, ruptured surfaces were observed in noodles coated with 20 and 30% salt. The enhanced salt release from the coatings was demonstrated in an in vivo analysis, with the released salt occurring rapidly from HC and SC coatings. HC-Na10 and SC-Na10 noodles had a shelf life of more than 8 days when stored at 4 °C, which is longer than HC-Na0 and SC-Na0 noodles. Storage at 4 °C decelerated the microbiological growth, changes in pH and CIE L* values in salt-coated noodles than storage at 25 °. Thus, HC-Na10 and SC-Na10 could be suitable formulations to replace commercial YAN.

Superheated steam processing of cereals and cereal products: A review

The concept of superheated steam (SS) was proposed over a century ago and has been widely studied as a drying method. SS processing of cereals and cereal products has been extensively studied in recent years for its advantages of higher drying rates above the inversion temperature, oxygen-free environment, energy conservation, and environmental protection. This review provides a brief introduction to the history, principles, and classification of SS. The applications of SS processing in the drying, enzymatic inactivation, sterilization, mycotoxin degradation, roasting, and cooking of cereals and cereal products are summarized and discussed. Moreover, the effects of SS processing on the physicochemical properties of cereals and the qualities of cereal foods are reviewed and discussed. The applications of SS for cereal processing and its effects on cereal properties have been extensively studied; however, issues such as the browning of cereal foods, thermal damage of starch, protein denaturation, and nutrition loss have not been comprehensively studied. Therefore, further studies are required to better understand the mechanism of the quality changes caused by SS processing and to expand the fields of application of SS in the cereal processing industry. This review enhances the understanding of SS processing and presents theoretical suggestions for promoting SS processing to improve the safety and quality of cereals and cereal products.

Effect of thermal treatments on the matrix components, inherent glycemic potential, and bioaccessibility of phenolics and micronutrients in pearl millet rotis

Pearl millet (PM) is a nutri-cereal rich in various macro and micronutrients required for a balanced diet. Its grains have a unique phenolic and micronutrient composition; however, the lower bioaccessibility of nutrients and rancidity of flour during storage are the major constraints in its consumption and wide popularity. Here, to explore the effect of different thermal processing methods, i.e., hydrothermal (HT), microwave (MW), and infrared (IR) treatments, on the digestion of starch, phenolics, and microelements (Fe and Zn), an in vitro digestion model consisting of oral, gastric and intestinal digestion was applied to PM rotis. The hydrothermally treated PM roti was promising as it showed lower inherent glycemic potential (60.4%) than the untreated sample (72.4%) and less enzymatic activities associated with rancidity in PM flour. FTIR revealed an increased ratio of 1047/1022 cm^-1 in the hydrothermally treated sample, reflecting the enhancement of the structurally ordered degree and compactness of starch compared to other thermal treatments. A tighter and more compact microstructure with an agglomeration of starch in the hydrothermally treated PM flour was observed by SEM. These structural changes could provide a better understanding of the lower starch digestion rate in the hydrothermally treated flour. However, HT treatment significantly (P < 0.05) reduced the bioaccessibility of phenolics (10.6%) compared to native PM rotis and slightly reduced the Fe (2%) and Zn (3.2%) bioaccessibility present in PM rotis.

Influences of Particle Size and Addition Level on the Rheological Properties and Water Mobility of Purple Sweet Potato Dough

This paper investigated the effects of different particle sizes and addition levels of purple sweet potato flour (PSPF) on the rheological properties and moisture states of wheat dough. There was deterioration in the pasting and mixing properties of the dough, due to the addition of PSPF (0~20% substitution), which was reduced by decreasing the particle size of the PSPF (260~59 μm). Dynamic rheology results showed that PSPF enhanced the elasticity of the dough, providing it solid-like processability. PSPF promoted the binding of gluten proteins and starch in the dough, resulting in a denser microstructure. Differential scanning calorimetry and low-field nuclear magnetic resonance showed that PSPF converted immobilized water and freezable water to bound water and non-freezable water in the dough, making the dough more stable, and that the reduction in PSPF particle size facilitated these processes. Our results provide evidence for the great application potential of purple sweet potatoes for use in flour-based products.

The Quality Characteristics Comparison of Stone-Milled Dried Whole Wheat Noodles, Dried Wheat Noodles, and Commercially Dried Whole Wheat Noodles

To explore the quality differences between dried wheat noodles (DWNs), stone-milled dried whole wheat noodles (SDWWNs), and commercially dried whole wheat noodles (CDWWNs), the cooking quality, texture properties, microstructure, protein secondary structure, short-range order of starch, antioxidant activity, in vitro digestive properties, and estimated glycemic index (eGI) of the noodles were investigated. The results showed that the cooking loss of SDWWNs was significantly lower than that of CDWWNs. The springiness, cohesiveness, gumminess, chewiness, and resilience of SDWWNs reached the maximum, and the tensile strength was significantly increased. The continuity of the gluten network of SDWWNs was reduced, and more holes appeared. The protein secondary structure of the SDWWNs and CDWWNs was mainly dominated by the β-sheet and β-turn, and the differences in the starch short-range order were not significant. Prior to and after the in vitro simulated digestion, the DPPH radical scavenging activity, the hydroxyl radical scavenging activity, and the total reducing power of the SDWWNs were the highest. Although the digested starch content of SDWWNs did not differ significantly from that of CDWWNs, the eGI was significantly lower than that of the CDWWNs and DWNs. Overall, the SDWWNs had certain advantages, in terms of quality characteristics.

Effect of Sitophilus zeamais (Coleoptera: Curculionidae) Infestation on the Protein Physicochemical and Structural Properties of Wheat Grain

Boring pests such as Sitophilus zeamais (S. zeamais) are major threats in grain storage. However, how these pests affect the proteins of stored grains remains largely unknown. Here we aimed to investigate the effect of S. zeamais infestation on wheat protein during postharvest storage. In this study, wheat grain infested by S. zeamais was sampled at egg (4 d), larval (20 d), pupal (35 d), and adult stages (45 d), respectively. The protein's physicochemical and structural properties and the edible quality of whole wheat noodle were analyzed. The results showed that S. zeamais infestation significantly decreased the quality of wheat protein by altering its constitution and structure properties. Especially, compared with the control, the content of wet and dry gluten, gluten index, sodium dodecyl sulfate sedimentation volume, sulfhydryl groups, and disulfide bonds in insect-infested wheat decreased by 19.40, 5.42, 18.40, 8.12, 29.13, and 14.30%, respectively, during the storage period of one life cycle of S. zeamais. Additionally, the proportions of wheat protein fractions (albumin [1.16-fold], globulin [0.96-fold], gliadin [1.16-fold], and glutenin [0.95-fold]) and secondary structures (α-helix [0.91-fold], β-fold [0.96-fold], β-turn [1.06-fold], and random coil [1.05-fold]) of protein changed significantly, and the gluten network structure was broken in S. zeamais-infested wheat. Furthermore, the color of whole wheat noodle became darker, cooking loss rate increased, and textural properties (hardness, adhesiveness, springiness, cohesiveness, chewiness, and resilience) decreased as well. The results in the present study provided new insights for analyzing the quality deterioration mechanism and further quality improvement of boring pests-infested wheat grain.

Effect of Frying Process on Nutritional Property, Physicochemical Quality, and in vitro Digestibility of Commercial Instant Noodles

The effects of frying process on the nutritional property, physicochemical quality, and in vitro digestibility of instant noodle products are investigated in this study. Scanning electron microscope (SEM) and Fourier transform infrared spectrometer (FT-IR) were also used to explore the changes in the microstructure and protein transformation. Noodles, after the frying process, showed a lower proportion of carbohydrate, protein, fiber, and also total starch and digestible starch, but higher content of fat and resistant starch in the proximate analysis. The frying process was also considered to improve the texture, surface color, and sensory properties of instant noodle products, accompanied by better cooking quality, including shorter cooking time and lower cooking loss during the rehydration. The honeycomb-like, porous, and less uniformed structure, and also the higher levels of β-sheets and β-turns, and the lower proportion of α-helixes of protein structure from fried instant noodle was also observed. The in vitro digestibility of starch and protein were downregulated in the fried group (81.96% and 81.31, respectively, on average) compared with the non-fried group (97.58% and 88.78, respectively, on average). Thus, the frying process lowered the glycemic index and regulated protein secondary structure by inhibiting continuous digesting enzyme activity, generating starch-lipid complexes, and changing the levels of protein transformation. In conclusion, our findings will provide an innovative evaluation of the frying process on instant noodles and even other various starch-based prepared food products.

Holistic View of Starch Chemistry, Structure and Functionality in Dry Heat-Treated Whole Wheat Kernels and Flour

Heat treatment is used as a pre-processing step to beneficially change the starch properties of wheat flour to enhance its utilisation in the food industry. Heat-treated wheat flour may provide improved eating qualities in final wheat-based products since flour properties predominantly determine the texture and mouthfeel. Dry heat treatment of wheat kernels or milled wheat products involves heat transfer through means of air, a fluidising medium, or radiation—often resulting in moisture loss. Heat treatment leads to changes in the chemical, structural and functional properties of starch in wheat flour by inducing starch damage, altering its molecular order (which influences its crystallinity), pasting properties as well as its retrogradation and staling behaviour. Heat treatment also induces changes in gluten proteins, which may alter the rheological properties of wheat flour. Understanding the relationship between heat transfer, the thermal properties of wheat and the functionality of the resultant flour is of critical importance to obtain the desired extent of alteration of wheat starch properties and enhanced utilisation of the flour. This review paper introduces dry heat treatment methods followed by a critical review of the latest published research on heat-induced changes observed in wheat flour starch chemistry, structure and functionality.

An Analytical Method Based on Electrochemical Sensor for the Assessment of Insect Infestation in Flour

Uric acid is an important indicator of the insect infestation assessment in flour. In this work, we propose a method for uric acid detection based on voltammetry. This technique is particularly considered for the physicochemical properties of flour and contains a simple pretreatment process to rapidly achieve extraction and adsorption of uric acid in flour. To achieve specific recognition of uric acid, graphene and poly(3,4-ethylenedioxythiophene) (PEDOT) were used for the adsorption and concentration of uric acid in flour. The adsorbed mixture was immobilized on the surface of a screen-printed electrode for highly sensitive detection of the uric acid. The results showed that electrocatalytic oxidation of uric acid could be achieved after adsorption by graphene and PEDOT. This electrocatalytic reaction allows its oxidation peak to be distinguished from those of other substances that commonly possess electrochemical activity. This voltammetry-based detection method is a portable and disposable analytical method. Because it is simple to operate, requires no professional training, and is inexpensive, it is a field analysis method that can be promoted.

Effect of Gaseous Chlorine Dioxide Treatment on the Quality Characteristics of Buckwheat-Based Composite Flour and Storage Stability of Fresh Noodles

In this study, the effects of gaseous chlorine dioxide treatment on the physicochemical properties of buckwheat-based composited flour (buckwheat-wheat-gluten) and shelf-life of fresh buckwheat noodles (FBNs), as well as the textural qualities and sensory properties of noodles were investigated. Chlorine dioxide treatment significantly reduced the total plate count (TPC) and the total flavonoids content in the mixed flour (p < 0.05), but the whiteness, development time and stability time were all increased. During storage, the microbial growth and darkening rate of FBNs made from chlorine dioxide treated buckwheat-based composite flour (CDBF) were delayed significantly, slowing the deterioration and improving storage stability of buckwheat noodles. In addition, chlorine dioxide treatment had no apparent adverse effect on the cooking loss and sensory characteristics during noodle storage. This finding would provide a new concept for the production of “low bacterial buckwheat-based flour” and have important consequences for the application of gaseous chlorine dioxide in food industry.

Changes of lipids in noodle dough and dried noodles during industrial processing

This study investigated the changes of lipids during the industrial preparation of noodle dough and dried noodles, including the hydration, sheeting, and drying processes. The results showed that industrial processing markedly influenced the stability of lipids during the preparation of dried noodles. The contents of total free fatty acids, polyunsaturated fatty acids, and free lipids were reduced, while peroxide values increased during the hydration and sheeting processes, showing the instability of lipids. The increase in lipid oxidation may have been due to the activation of lipoxygenase. Although its activity declined by 45.7% in the hydration process compared to that of the native wheat flour (198.5 ± 20.4 U/g/min), the residue activity should have been high enough to oxidize lipids. Interestingly, lipase activity remained relatively stable. In addition, an obvious increase of carbon-centered free radicals was observed during the entire processing. In conclusion, the industrial processing, especially the hydration process, markedly changed the lipid profile and promoted lipid oxidation during the preparation of dried noodles. PRACTICAL APPLICATION: The present study showed the positive relationship between endogenous lipid degrading enzymes and the degradation of lipids and elucidated the role of industrial processing on lipid stability in noodle dough and dried noodles. The results of the present study will also help us to understand more about the sensory quality of dried noodles during preparation, as well as to develop high quality of wheat-based food products.

Microencapsulation of nattokinase from fermentation by spray drying: Optimization, comprehensive score, and stability

Nattokinase from fermentation has recently gained more attention due to its beneficial effects on cardiovascular system. However, the instability of free nattokinase limits its application. The aim of the study was to develop a spray-drying microencapsulation process to obtain the nattokinase powder with high activity, high quality, and strong storage stability. Hence, the microencapsulation process of nattokinase from fermentation by spray drying was optimized. Experiments of single-factor and response surface methodology were used to assess the comprehensive scores and nattokinase activities. According to single-factor and response surface methodology results, optimum parameters of microencapsulation process of the nattokinase power by spray drying were 30% of mass ratio of wall materials, 139°C of air inlet temperature, 8 L/h of feed rate, and 80°C of outlet temperature. The final optimized result encompassed a comprehensive score of 96, nattokinase activity of 1,340 IU/ml, and moisture content of 4.1 ± 0.1%. In addition, the microencapsulated nattokinase power showed strong storage stability in the conditions of different temperatures and pH. After 30 days of storage, the nattokinase powder was still white or light yellow, with a special smell, no peculiar smell and paste taste, and no impurity. These results build the basis of further industrialization of the nattokinase powder from fermentation broth by spray drying.

Effect of Superheated Steam Treatment on the Lipid Stability of Dried Whole Wheat Noodles during Storage

Dried whole wheat noodles (DWWN) are a kind of nutritious convenience food with broad market prospects. However, due to the presence of high content of unsaturated fatty acids (UFAs) and lipid degrading enzymes, the shelf life and edible quality of DWWN are easily affected. This study explored the effect of superheated steam treatment (SST-155 °C-10 s, SST-170 °C-10 s, SST-190 °C-5 s) on the lipid stability of DWWN. The lipase, lipoxygenase and peroxidase of the DWWN treated with superheated steam were completely passivated during storage. After 12 weeks of storage, the fatty acid value of DWWN increased by 35.1, 17.9, 15.9, 24.6 mg NaOH/100 g in the groups of control, SST-155 °C-10 s, SST-170 °C-10 s, SST-190 °C-5 s, respectively; whereas the content of UFAs decreased by 13.5%, 6.8%, 5.4%, and 2.7%, respectively. The content of 2-pentylfuran in the SST-155 °C-10 s, SST-170 °C-10 s, SST-190 °C-5 s group was 0.7, 0.6, and 0.4-fold than that of the control group, respectively. In addition, the total tocopherol and total volatile compounds of the SST-190 °C-5 s group were 2.4 and 0.7-fold than that of the control group, respectively. Therefore, SST should be a new technology that can improve the lipid stability of DWWN.

Effect of superheated steam treatment on the lipid stability of whole wheat flour

This study aimed to investigate the effect of superheated steam treatment (SST) on lipid stability of whole wheat flour (WWF) during storage. After SST, the lipase and peroxidase of WWF were inactivated, and lipoxygenase activity was lower than 5% of its initial value. The total tocopherols decreased slightly in all SST groups, especially it only decreased by 1.1% at 190 °C for 5 s. Furthermore, the increase of fatty acid value in the control group was over 100-fold than that of the SST groups during storage. The unsaturated fatty acids and total tocopherols in WWF decreased gradually, but the decrease was alleviated by SST at 190 °C for 5 s. After storage, the relative content of hexanal and 2-pentylfuran in the SST groups were 4 and 0.3-fold than those in the control group, respectively. Thus, SST may be a potential approach to stabilise the quality of WWF.

Evaluation of cooking performance, structural properties, storage stability and shelf life prediction of high-moisture wet starch noodles

Cooking performance, micro- and molecular structure, storage stability and shelf-life prediction of high-moisture wet starch noodles (SN) were investigated. SEM images revealed that compared to dried SN, cooked wet SN had more evenly honeycomb-like network with smaller size of pores, indicating stronger interaction among molecules and causing favorable cooking performance. XRD and ATR-FTIR results evidenced that wet SN contained more complete crystallites and higher proportion of crystalline region. During storage, the quality decay of wet SN was mainly associated to the increment of total aerobic viable count (TAVC), titrable acidity and amylase, as well as the decreased textural hardness, overall acceptability and lightness. Based on TAVC, titrable acidity and overall acceptability, predicted shelf-life of vacuum-packed wet SN at 25 °C was 15.31, 21.54 and 16.65 weeks respectively, with relative error all within 20%, proving that the validated model could be an effective tool for monitoring the shelf-life of wet SN.

Quality Characteristics of Semi-Dried Restructured Jerky Processed Using Super-Heated Steam

Moisture content and water activity play important roles in extending the shelf life of dried meat products, such as jerky. However, the commonly used hot air drying process is time-consuming, costly, and adversely affects the quality of dried meat products, warranting the development of an advanced and economical drying method. This study investigated the effect of super-heated steam (SHS) drying on the quality characteristics of semi-dried restructured jerky as a measure to prevent the excessive quality deterioration of meat products during drying. The control sample was dried using hot air, and the treatment samples were dried using SHS at different temperatures (200, 250, and 300 °C) and for different durations (90, 105, and 120 min). With increasing SHS temperature and duration, the moisture content, water activity, and residual nitrite content of the jerky were reduced. The shear force values for treatments at 200 and 250 °C were lower than those for the control. With a non-significant difference in lipid oxidation compared with the control, the overall acceptability score was the highest for the treatment at 250 °C for 120 min. In conclusion, SHS (250 °C for 120 min) drying has a potential industrial value to replace the hot air drying method.