Shelf-life extension of semi-dried buckwheat noodles by the combination of aqueous ozone treatment and modified atmosphere packaging

Recent advances in extending the shelf life of fresh wet noodles: Influencing factors and preservation technologies

Fresh wet noodles (FWNs) are popular among people and have attracted increasing attention because of their characteristics of freshness, chewiness, good taste, and better maintenance of noodle flavor. However, due to the high moisture content and abundance of nutrients in FWN, they are prone to spoilage, which shortens their shelf life and reduces their quality, greatly restricting their large-scale production. Therefore, seeking effective preservation methods to prolong the shelf life is a major breakthrough for the industrialization of FWN. The present review provides a comprehensive overview of the main factors that contribute to the spoilage and degradation of FWN. These factors encompass microorganisms, moisture content, nutritional composition, enzymes, and storage temperature. Moreover, the recent developments in novel shelf-life extension technology applied to FWN, such as chemical preservatives, natural preservatives, physical treatment technologies, and composite preservation technology, are presented and discussed. From the literature reviewed, the application of technologies, such as adding preservatives, modified atmosphere packaging, microwave, cold plasma, ozone, and other technologies, has a certain effect on improving the shelf life of FWN, but the single preservation technology still has some deficiencies. In order to further improve the preservation efficiency, using two or more preservation methods is an important direction for future research on the preservation technology of FWN.

Impact of emerging food processing technologies on structural and functional modification of proteins in plant-based meat alternatives: An updated review

In the past decade, the plant-based meat alternative industry has grown rapidly due to consumers' demand for environmental-friendly, nutritious, sustainable and humane choices. Consumers are not only concerned about the positive relationship between food consumption and health, they are also keen on the environmental sustainability. With such increased consumers' demand for meat alternatives, there is an urgent need for identification and modification of protein sources to imitate the functionality, textural, organoleptic and nutritional characteristics of traditional meat products. However, the plant proteins are not readily digestible and require more functionalization and modification are required. Proteins has to be modified to achieve high quality attributes such as solubility, gelling, emulsifying and foaming properties to make them more palatable and digestible. The protein source from the plant source in order to achieve the claims which needs more high protein digestibility and amino acid bioavailability. In order to achieve these newer emerging non-thermal technologies which can operate under mild temperature conditions can reach a balance between feasibility and reduced environmental impact maintaining the nutritional attributes and functional attributes of the proteins. This review article has discussed the mechanism of protein modification and advancements in the application of non-thermal technologies such as high pressure processing and pulsed electric field and emerging oxidation technologies (ultrasound, cold plasma, and ozone) on the structural modification of plant-based meat alternatives to improve, the techno-functional properties and palatability for successful food product development applications.

The effect of chitosan oligosaccharides on the shelf-life and quality of fresh wet noodles

In this study, the effects of chitosan oligosaccharides (COS) on the microbial stability and quality properties of fresh wet noodles were evaluated. The addition of COS prolonged the shelf-life of fresh wet noodles at 4 °C by 3-6 days and effectively inhibited the growth of acidity value. However, the presence of COS increased the cooking loss of noodles significantly (P < 0.05) and decreased the hardness as well as tensile strength significantly (P < 0.05). The enthalpy of gelatinization (ΔH) was decreased by COS in the differential scanning calorimetry (DSC) analysis. Meanwhile, the addition of COS decreased the relative crystallinity of starch (from 24.93 % to 22.38 %) without changing the type of X-ray diffraction pattern, revealing that COS weakened the structural stability of starch. In addition, COS was observed to impair the development of compact gluten network by confocal laser scanning micrographs. Further, the free-sulfhydryl groups content and sodium dodecyl sulphate-extractable protein (SDS-EP) values of cooked noodles increased significant (P < 0.05), confirming the obstruction on the polymerization of gluten proteins during the hydrothermal process. Although COS adversely affected the quality of noodles, it was outstanding and feasible for the preservation of fresh wet noodles.

Evaluation of the Storage Stability and Quality Properties of Fresh Noodles Mixed with Plasma-Activated Water

Enhancing the quality retention of fresh noodles remains challenging. In this study, we investigated the effect of dough mixing with plasma-activated water (PAW) of different activation times on the storage stability and quality characteristics of fresh noodles. It was found that the total plate count in the fresh noodles prepared by PAW (PAWN) showed no obvious inhibition during storage at 25 °C, but could be significantly reduced at 4 °C as compared with the control. The decrease in L* value and pH of the PAWN was significantly retarded during storage, indicating an enhanced storage stability. The stability time of dough mixed with PAW could be significantly improved. PAW treatment decreased the viscosity properties and setback value of starch, while enhancing the interaction of water and non-water components in fresh noodles. In addition, dynamic polymerization and depolymerization of proteins were detected in Size-Exclusion High-Performance Liquid Chromatography (SE-HPLC) profiles of PAWN. The hardness and adhesiveness of the cooked noodles decreased, while the springiness significantly increased. These results implied the potential of PAW in improving the storage stability and quality of fresh noodles.

Buckwheat noodles: processing and quality enhancement

In recent years, buckwheat noodles have gained increased importance because of their functional properties. These qualities are attributed to the abundance of bioactive compounds (e.g., rutin, quercetin) and nutraceuticals (e.g., B vitamins, unsaturated fatty acids). Buckwheat noodle consumption has been shown to be associated with improved metabolic health. Buckwheat flour exhibits properties similar to those of common cereal flours in food processing, but devoid of gluten. However, the maintenance of good textural properties and high sensory acceptability are key challenges in the development of gluten-free products, and these limitations prevented widespread application of buckwheat in the food industry. Nevertheless, continuous technological developments related to raw materials processing, noodle processing, and noodle quality enhancement have contributed to the growing popularity and acceptability of buckwheat noodles in recent times. These improvements could render buckwheat noodles a healthy gluten-free alternative to wheat noodles.

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.

Understanding the deterioration of fresh brown rice noodles from the macro and micro perspectives

The microbial compositions, quality characteristics, and structural changes in fresh brown rice noodles (FBRN) during storage were investigated. Total plate count and mold and yeast counts increased while the pH decreased during storage. Metagenomic sequencing revealed that the microbial composition of FBRN changed throughout storage. A comprehensive investigation of the variation in lipid content demonstrated that hydrolytic rancidity was responsible for lipid deterioration. LF-NMR showed an increase in the proportion of bound water and a decrease in the proportion of free water in FBRN. Moreover, significant changes in edible qualities were observed. The cooking loss increased three-fold and noodles hardness reduced by approximately 23%. Further, the high initial aldehyde content of FBRN diminished almost completely, while that of alcohols and esters increased, leading to significant flavor deterioration. The correlation and factor analysis suggested that the TPC and MY counts could be used as key indicators of FBRN deterioration.

Effect of Humidity-Controlled Dehydration on Microbial Growth and Quality Characteristics of Fresh Wet Noodles

Humidity-controlled dehydration (HCD) was innovatively applied in this paper to control the growth of microorganisms in fresh wet noodles (FWN). Effects of HCD treatment with different temperatures (40, 60 or 80 °C), relative humidity (RH, 50%, 70% or 90%) and treatment time (5–32 min) on the total plate count (TPC), the shelf-life, and qualities of FWN were investigated. The results showed that HCD reduced the initial microbial load on the fresh noodles and extended the shelf-life up to 14–15 days under refrigeration temperature (10 °C). A 1.39 log₁₀ CFU/g reduction for the initial TPC was achieved after HCD treatment at the temperature of 60 °C and RH of 90%. HCD with higher RH had a more positive influence on quality improvement. The L* values, the apparent stickiness, and the cooking properties of the noodle body were improved by HCD while good sensory and texture quality of noodles were still maintained after the dehydration process.

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.

Dissimilarity in sensory attributes, shelf life and spoilage bacterial and fungal microbiota of industrial-scale wet starch noodles induced by different preservatives and temperature

Shelf life, storage stability and microbial growth of wet starch noodles during storage were investigated, and spoilage microbiota was also analyzed to further reveal the decisive factor shaping the microbial community. Sensory analysis and microbiological results indicated that starch noodles treated with sodium dehydroacetate and stored at 4 °C could effectively delay the moldy decay and extend the shelf-life to 50 days, as compared to control and other treatments. In wet starch noodles, molds were found to have a higher spoilage potential than bacteria and yeasts. 16S rDNA sequencing revealed that preservatives, rather than temperature, could cause the significant difference (PERMANOVA p = 0.001) of spoilage bacterial community among samples and sodium dehydroacetate could markedly reduce the bacterial diversity. ITS rDNA sequencing results demonstrated that temperature was the decisive factor in shaping fungal spoilage microbiota (Mantel test r = 0.413, p = 0.002). Besides, Spearman correlation analysis illustrated that the abundance of some microorganisms such as Pseudomonas, Aspergillus and Penicillium were found to be significantly correlated with pH or temperature. These findings provide guiding information in the selection of preservatives and environmental condition for this high-moisture starch noodles.

Inhibitory effects of sorbitol on the collapse and deterioration of gluten network in fresh noodles during storage

In this paper, the inhibitory effects of sorbitol on the collapse of gluten network and textural deterioration of fresh noodles during storage were investigated, based on the changes in macroscopic and microscopic characteristics of gluten protein. Appropriate addition (≤2%) of sorbitol increased dough viscoelasticity and extension energy. Sorbitol significantly inhibited the increase of cooking loss and adhesiveness of fresh noodles, and the decrease of hardness, springiness, LA-SRC value, and GMP weight during storage. SEM images showed that sorbitol retarded the deterioration of gluten network, with maintained continuous and ordered structure after 48 h. Sorbitol enhanced the hydrogen bond interactions in gluten system and promoted dynamic depolymerization and repolymerization of gluten protein molecules during processing and cooking, this may induce the texture stability. Sorbitol as a low-molecular polyol can inhibit the deterioration in gluten network and fresh noodle texture during storage, although showing no influence on the growth of microorganisms.

Effect of thermal treatment on the physicochemical, ultrastructural and nutritional characteristics of whole grain highland barley

Highland barley (HB) was subjected to three thermal treatments (heat fluidization, microwave, and baking) and assessed for physicochemical, ultrastructural and nutritional properties. After thermal treatments, the hardness, bulk density, thousand kernel weight, length/breadth ratio, and color difference decreased significantly, while puffing index increased. Meanwhile, the formation of fissure was observed in the appearance. Microstructure images illustrated that numerous micropores were evenly distributed in the endosperm structure, and aleurone layer cells were deformed by compression. Furthermore, a dramatically disruption of endosperm cell walls and slightly deformation of outer layers were observed by confocal laser scanning microscopy. Moreover, a notably decrease in total phenolics (14.02%-36.91%), total flavonoids (25.28%-44.94%), and bound phenolics (8.99%-27.53%) was detected, while free phenolics (8.81%-43.40%), β-glucan extractability (4.71%-43.66%), antioxidant activity (71.87%-349.77%), and reducing power (3.05%-56.13%) increased significantly. Greatest increase in nutritional values was caused by heat fluidization, which possessed the potential for development of ready-to-eat functional foods.

Effect of ozone treatment on processing properties of wheat bran and shelf life characteristics of noodles fortified with wheat bran

The effects of ozone treatment on microorganism and volatile substances of wheat bran, as well as on the quality of fresh noodles made from wheat flour supplemented with ozone treated wheat bran were studied in this paper. Results showed that the optimized condition of ozone treatment was 50 min treatment time and optimized condition of bran properties were 15% moisture content, 15 mesh particle size. Under the optimized condition microbial contents in the wheat bran can be reduced more than 90% after ozone treatment. There was no significant increase in microbial contents of treated wheat bran during storage, whereas the types of volatile substances were gradually decreased. After the ozone treated wheat bran was added back to wheat flour and used for fresh noodles preparation, there were relatively few changes in the quality of the fresh noodles but the shelf life was prolonged as compared to the untreated bran.

Inhibition of hexose oxidase on the dark spots in fresh wet noodle sheets: A feasible prevention of dark spots

Hexose oxidase was a feasible prevention for the dark spots in the fresh wet noodle sheets (FWNS). The chemical mechanism that hexose oxidase recucing the melanins of dark spots was discussed basis on the UPLC-TOF-MS analysis of the polyphenol oxidase (PPO)-catechol system. In the process of PPO browning, hexose oxidase catalyzed the oxidation of o-benzoquinone derivatives and their oligomers, hindering the formation of melanins. Hexose oxidase was efficient in FWNS with low ash content when water addition was 24%~44% or pH range was 4 ~ 7.5. Hexose oxidase could inhubit dark spots in the presence of 10 metal ions. The recommended addition amount was 40 ~ 60 ppm, by which the dark spots could be compolitely inhibited. Hexose oxidase was also suitable for wholewheat and oat FWNS, ΔL_6d of wholewheat and oat FWNS were reduced by 4 and 7.98, respectively.

Impact of aqueous ozone mixing on microbiological, quality and physicochemical characteristics of semi-dried buckwheat noodles

The microbiological, microstructural, and physicochemical impact of aqueous ozone mixing (AOM) on semi-dried buckwheat noodles (SBWN) was elucidated in this study. Microbiological measurements declared that AOM reduced the initial total plate count (TPC) of SBWN significantly (P < 0.05) with a prolonged shelf-life of 2 ~ 5 days. Meanwhile, AOM reduced the cooking loss and water absorption along with the enhancement of hardness and tension force. Scanning electron microscopy (SEM) showed that the protein network of surface and cross section became continuous and compact, and wrapped starch granules more effectively. Moreover, an obvious increase in the intensity of the high molecular protein bands was observed in the sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) patterns. Furthermore, the sodium dodecyl sulfate extractable protein (SDSEP) under non-reducing condition obviously decreased, and then the SDSEP under reducing condition changed insignificantly (P > 0.05). These results indicated that AOM mainly promoted the protein cross-linking of SBWN by disulfide bond (SS) cross-links.

Study on the shelf life and quality characteristics of highland barley fresh noodles as affected by microwave treatment and food preservatives

In this work, the effect of microwave (MW), ε-poly-L-lysine (ε-PL), calcium propionate (CP), and their combinations on the shelf life and quality characteristics of highland barley fresh noodle (HBFN) was studied. Firstly, the mixed flour was treated by MW (800 W) for different time. Subsequently, HBFN was prepared by mixing flour and sterilized water with addition of 0.04% ε-PL combined with different concentrations of CP (0.025%, 0.020%, 0.015%) and stored at 25 ± 1°C. Changes of total plate count (TPC), moisture content, water state, textural properties, color, and pH in HBFN were monitored during storage. The results indicated that microwave treatment (40 s) provided 30% reduction of initial TPC of the flour without decline of noodle quality. Shelf life of HBFN treated with MW + ε-PL (0.04%) + CP (0.02%/0.025%) reached 80 and 88 hr, respectively, and had good edible qualities during storage.

Quality characteristics of fresh wet noodles treated with nonthermal plasma sterilization

Nonthermal plasma treatment has been a widely acknowledged effective method for food sterilization. This study presents the potential of nonthermal dielectric barrier discharge (DBD) plasma treatment for sterilization of the surface of the fresh wet noodles (FWNs). The plasma treatment achieved a more than one logarithmic reduction of the total bacterial count and total mold count as measured by counting the total microorganisms and filamentous fungi, respectively. In addition, the qualities of FWNs exposed to nonthermal DBD plasma treatment had no undesirable changes to color, texture, acidity and water distribution as measured by a texture analyzer, color meter and low-field nuclear magnetic resonance (LF-NMR), respectively. Thus, nonthermal DBD plasma treatment is a promising alternative to the traditional sterilization method applied in FWN industry and provides a new idea for the preservation and processing of fresh food.

Extruded whole buckwheat noodles: effects of processing variables on the degree of starch gelatinization, changes of nutritional components, cooking characteristics and in vitro starch digestibility

The effects of processing variables on the degree of gelatinization (DG), changes of nutritional components, cooking characteristics and in vitro starch digestibility of extruded whole buckwheat noodles were investigated.

Packaging to prolong shelf life of preservative-free white bread

This research studied various types of packaging to prolong the shelf life of non-preservative white bread. Three types of blown film packages were used, i.e. a single LDPE layer incorporated with an oxygen scavenger, a single LDPE layer containing an oxygen absorber sachet, and three layers of LDPE laminated with O-nylon. The effects of modified packaging atmosphere, i.e. 5, 10, and 21 vol. % of oxygen in nitrogen balance, on the shelf life was also included. Characterization of the packaging films was carried out using several techniques, such as Oxygen Transmission Rate (OTR) and an optical microscopy. Headspace gases, microbial count, as well as physical appearance were used to evaluate the shelf life. The optical microscopic images showed that incorporating the oxygen scavenger into the plastic film produced small pores, contributing to a passive function of the films as their OTRs were significantly enhanced. However, the microbial growth on bread stored in those packages was suppressed, implying that the intermediate generated from scavenging reaction might act as a fungistatic. Even though the scavenging capability of the oxygen absorber sachet lasted only for 4 days, the fungi and mould development thereafter was still lower compared to the package without the sachet. The prolonging white bread shelf life was found to be primarily dependent on two factors. The package with a high oxygen barrier such three-layer films defeated microorganisms. With a low initial oxygen level of around 5% by volume, the bread shelf life could be prolonged up to 5–7 days.