Effect of heat-treated flour on the quality and storage stability of fresh noodles

Effect of pre-gelatinized highland barley flour on texture and digestibility of fortified dried noodles: A protein and starch perspective

The contribution of pre-gelatinized highland barley flour to noodles was investigated by preparing and comparing pre-gelatinized (PN) and native (NPN) whole-grain noodles at 30-70 % fortification levels. A progressive reduction in gluten content and increased starch granule exposure were observed in NPN with increasing highland barley incorporation, while PN maintained structural integrity with minimal starch granule exposure and gluten disruption. This might be attributed to crystallinity reduction (14.3 % → 7.1 %) and short-range ordered structure disruption (0.85 → 0.82) in PN, facilitating denser starch network and V-type complex formation. The protein secondary structure in PN shifted from α-helix to β-sheet, resulting in more SS bonds. The hardness, springiness and chewiness of PN70 were 29.51 %, 71.95 % and 99.64 % higher than those of NPN70. Moreover, PN70 exhibited the highest content of resistant starch and the slowest digestion rate. These findings advance research on noodle textural and functional enhancement through pre-gelatinization modification.

An overview on the dry heat treatment (DHT) for starch modification: Current progress and prospective applications

Starch plays a pivotal role in numerous applications, making the enhancement of its functionality through physical processes increasingly important. Dry heat treatment (DHT) is a straightforward and eco-friendly technique that significantly improves starch characteristics and boosts food quality. This method has emerged as a focal point in starch modification research in recent years. This paper reviews current studies on the DHT of starches from various botanical sources, presenting key concepts and methodologies while delving into the impacts and mechanisms of DHT on the structural and physicochemical properties of starches. Furthermore, it elaborates on how additional components, such as ionic gums, amino acids, and sugars, can enhance the functionality of starches modified by DHT. Additionally, this review discusses the practical applications of dry heat-modified starches in the food industry, aiming to offer valuable insights for ongoing research and potential applications in enhancing food quality and functionality through innovative starch modifications.

Impact of rehydration on multi-scale structural transformations and starch digestibility of dried noodles

To understand the relationship between the structure and starch digestibility of dried noodles, the changes in multi-scale structure and in vitro starch digestibility of dried noodles with different protein contents (ranging from 10 % to 15 %) during rehydration were tracked. The results indicated that the hardness of dried noodles decayed according to the first-order exponential decay function, with rapid and slow stages. This depended on near-linear protein aggregation and near-logarithmic starch gelatinization. The gelatinization degree reached 70.9 to 79.4 % in the early stage of rehydration. Water absorption kinetics and distribution analysis revealed that the moisture migrating into the noodles was initially utilized for starch gelatinization. This led to the formation of a honeycomb gel structure at the edge of the noodles, which gradually spread from the edge to the center, as observed by SEM and CLSM. As rehydration progressed, the starch digestion degree increased. The digestion rate (k1) decreased with the formation of the composite gel structure, while k2 showed an increased trend. Additionally, with the increase in the protein content of noodles, the aggregation degree and increment were enhanced. This resulted in the formation of a more compact composite gel structure, which reduced the rate and extent of starch digestion within the noodles. When the noodles were overcooked, the C∞ of the high-protein samples was reduced by approximately 10 % compared to that of the low-protein samples. Overall, the formation of the composite gel structure reduces the heterogeneity of the noodles from the edge to the center, resulting in a closer starch digestion rate in fast and slow steps. Besides, the rapid and massive aggregation of proteins at high protein content contributed to the formation of a compact gel structure, which in turn interfered with the rate and extent of starch digestion.

Effect of surfactin on microbial content, appearance quality, and starch properties of fresh noodles during storage

Fresh noodles (FNs) are prone to quality deterioration during storage, negatively affecting their edibility. This study investigated the impacts of different surfactin concentrations on microbial content, appearance quality, and starch properties in FNs to enhance storage stability and shelf life. The addition of surfactin effectively controlled the microbial growth in FNs during storage, FNs containing 0.4 % surfactin maintained total aerobic plate count below 106 CFU/g for up to 72 h at 25 °C, which was at least 48 h longer than the control group. Furthermore, surfactin could inhibit yellowing and reduce the appearance of dark spots in FNs during storage. Results from Rapid Visco Analyzer, X-ray diffractometer, and Differential Scanning Calorimetry indicated that surfactin inhibited the decrease in starch viscosity, and the increase in relative crystallinity and enthalpy, and improved the storage stability of starch in FNs. This research provides a theoretical foundation for applying surfactin as an enhancer in FNs.

Insights into the effect mechanism of freeze-thaw cycles on starch gel structure and quality characteristics of frozen extruded whole buckwheat noodles

The effects of freeze-thaw cycles (FTC) on starch gel structure and quality characteristics of frozen extruded whole buckwheat noodles (FEWBN) were studied. The repeated FTC treatments induced the retrogradation of amylose which increased the compactness, crystallinity, hardness, and cooking time of FEWBN. However, with the increasing number of freeze-thaw cycles, the larger volume of ice crystals formed in the noodles destroyed the starch gel network structure to a certain extent, and led to the dehydration and syneresis of the noodles, and the quality deterioration. However, moderate amylose retrogradation occurred during the FTC treatment was found to be beneficial for the quality of FEWBN. After one time of FTC treatment, the cooking loss of 3.53 % was even lower compared with that without FTC treatment (4.61 %). After seven times of FTC treatment, the cooking loss of FEWBN was 6.53 %, and the breaking rate was still 0, indicating that FEWBN could resist the damage caused by temperature fluctuations on the internal structure of frozen food to a certain extent, and maintain good quality. This study establishes a fundamental basis for the development of buckwheat noodles with good freeze-thaw stability and high cooking quality.

Effects of debranched starch on physicochemical properties and in vitro digestibility of flat rice noodles

Aiming to develop flat rice noodles with both desirable textural quality and lower starch digestibility, we investigated the effect of adding indica rice debranched starch (RDBS) on the quality of flat rice noodles. In this study, adding RDBS to flat rice noodles enhanced their mechanical properties. Cooking characteristic analysis showed that incorporating RDBS into dried flat rice noodles increased the rehydration ratio by 16.1 % and reduced rehydration time by 26.5 %. Scanning electron microscopy (SEM) revealed the presence of microparticles formed through the self-assembly of RDBS within the network of flat rice noodles. X-ray diffraction (XRD) analysis demonstrated that the addition of RDBS elevated the crystallinity of the flat rice noodles, rising from 9.59 % to 22.57 %. In addition, the in vitro simulated digestion test suggested the addition of RDBS led to a threefold increase in the content of slowly digestible starch (SDS) and a ninefold increase in resistant starch (RS) content in flat rice noodles. This study found that adding RDBS into flat rice noodles can effectively reduce their digestion rate and improve their eating quality. It could be a promising approach for creating functional rice noodles aimed at alleviating public health concerns such as diabetes and obesity.

Improvement in Noodle Quality and Changes in Microstructure and Disulfide Bond Content through the Addition of Pepper Straw Ash Leachate

Every year, a significant amount of pepper stalks are wasted due to low utilization. The ash produced from pepper stalks contains a significant amount of alkaline salts, which are food additives that can enhance the quality of noodles. Therefore, utilizing natural pepper straw ash to improve the quality of noodles shows promising development prospects. In this study, pepper straw ash leachate (PSAL) was extracted and added to noodles. The quality of the noodles gradually improved with the addition of PSAL, with the best effect observed at a concentration of 18% (PSAL mass/flour mass). This addition resulted in a 57.8% increase in noodle hardness, a 55.43% increase in chewiness, a 19.41% rise in water absorption rate, and a 13.28% increase in disulfide bond content. These alterations rendered the noodles more resilient during cooking, reducing their tendency to soften and thus enhancing chewiness and palatability. Incorporating PSAL also reduced cooking loss by 57.79%. Free sulfhydryl groups decreased by 5.1%, and scanning electron microscopy revealed a denser gluten network structure in the noodles, with more complete starch wrapping. This study significantly enhanced noodle quality and provided a new pathway for the application of pepper straw resources in the food industry.

Effect of Bacteria Content in Wheat Flour on Storage Stability of Fresh Wet Noodles

The effect of bacteria content in wheat flour on shelf life and storage stability of fresh wet noodles (FWNs) was evaluated in this study. Nine kinds of wheat flour with different bacterial contents were selected to make FWNs. With the increase in total plate count (TPC) from 120 CFU/g to 5500 CFU/g in flour, the shelf life of FWNs decreased from 23 d to 9 d at 4 °C. During storage, the acidity increased, which was significantly correlated with the change of TPC (p < 0.05), and the pH value and L* value of FWNs decreased significantly (p < 0.05). Changes in viscosity characteristics of starch components were also detected, the higher the TPC in flour, the more obvious the viscosity decreased. Moreover, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) showed that with the deterioration of FWNs, some low molecular weight protein subunits increased; texture analysis showed that the hardness of noodles increased firstly and then decreased, the adhesiveness increased and the springiness decreased during storage. In summary, choosing flour with low TPC to prepare FWNs can extend the shelf life and slow down the quality deterioration of FWNs during storage at 4 °C.

Extension of the shelf-life of fresh pasta using modified atmosphere packaging and bioprotective cultures

Microbial stability of fresh pasta depends on heat treatment, storage temperature, proper preservatives, and atmosphere packaging. This study aimed at improving the microbial quality, safety, and shelf life of fresh pasta using modified atmosphere composition and packaging with or without the addition of bioprotective cultures (Lactobacillus acidophilus, Lactobacillus casei, Bifidobacterium spp., and Bacillus coagulans) into semolina. Three fresh pasta variants were made using (i) the traditional protocol (control), MAP (20:80 CO2:N2), and barrier packaging, (ii) the experimental MAP (40:60 CO2:N2) and barrier packaging, and (iii) the experimental MAP, barrier packaging, and bioprotective cultures. Their effects on physicochemical properties (i.e., content on macro elements, water activity, headspace O2, CO2 concentrations, and mycotoxins), microbiological patterns, protein, and volatile organic compounds (VOC) were investigated at the beginning and the end of the actual or extended shelf-life through traditional and multi-omics approaches. We showed that the gas composition and properties of the packaging material tested in the experimental MAP system, with or without bioprotective cultures, positively affect features of fresh pasta avoiding changes in their main chemical properties, allowing for a storage longer than 120 days under refrigerated conditions. These results support that, although bioprotective cultures were not all able to grow in tested conditions, they can control the spoilage and the associated food-borne microbiota in fresh pasta during storage by their antimicrobials and/or fermentation products synergically. The VOC profiling, based on gas-chromatography mass-spectrometry (GC-MS), highlighted significant differences affected by the different manufacturing and packaging of samples. Therefore, the use of the proposed MAP system and the addition of bioprotective cultures can be considered an industrial helpful strategy to reduce the quality loss during refrigerated storage and to increase the shelf life of fresh pasta for additional 30 days by allowing the economic and environmental benefits spurring innovation in existing production models.