Frozen Storage Time Research Articles

Effect of precooking time on the quality of noodles with different frozen storage time

Effect of precooking time on the quality of noodles with different frozen storage time

Assessment of fecal bacterial viability and diversity in fresh and frozen fecal microbiota transplant (FMT) product in horses

BackgroundCurrently, lack of standardization for fecal microbiota transplantation (FMT) in equine practice has resulted in highly variable techniques, and there is no data on the bacterial metabolic activity or viability of the administered product. The objectives of this study were to compare the total and potentially metabolically active bacterial populations in equine FMT, and assess the effect of different frozen storage times, buffers, and temperatures on an equine FMT product. Fresh feces collected from three healthy adult horses was subjected to different storage methods. This included different preservation solutions (saline plus glycerol or saline only), temperature (-20 °C or -80 °C), and time (fresh, 30, 60, or 90 days). Samples underwent DNA extraction to assess total bacterial populations (both live and dead combined) and RNA extraction followed by reverse transcription to cDNA as a proxy to assess viable bacteria, then 16s rRNA gene amplicon sequencing using the V1-V2 region.ResultsThe largest difference in population indices and taxonomic composition at the genus level was seen when evaluating the results of DNA-based (total) and cDNA-based (potentially metabolically active) extraction method. At the community level, alpha diversity (observed species, Shannon diversity) was significantly decreased in frozen samples for DNA-based analysis (P < 0.05), with less difference seen for cDNA-based sequencing. Using DNA-based analysis, length of storage had a significant impact (P < 0.05) on the bacterial community profiles. For potentially metabolically active populations, storage overall had less of an effect on the bacterial community composition, with a significant effect of buffer (P < 0.05). Individual horse had the most significant effect within both DNA and cDNA bacterial communities.ConclusionsFrozen storage of equine FMT material can preserve potentially metabolically active bacteria of the equine fecal microbiome, with saline plus glycerol preservation more effective than saline alone. Larger studies are needed to determine if these findings apply to other individual horses. The ability to freeze FMT material for use in equine patients could allow for easier clinical use of fecal transplant in horses with disturbances in their intestinal microbiome.

Frozen cheese curd as an intermediate for cheese making – homogenization as a tool to regain techno-functional properties

This study investigated the effect of milk homogenization/fat globule size on the plasticization of fresh and frozen stored cheese curd and its respective oiling-off behavior. The cheese was frozen either slowly in a freezing chamber or quickly with liquid nitrogen to study the influence of freezing, frozen storage, and thawing. For non-frozen cheese curd, a one-stage homogenization at 2 MPa before renneting still leads to plasticization, while relative oiling off is reduced from 2.6 to 1.9%. This was explained by reduced fat globule size and an increased surface area covered by whey proteins and casein, which is denser and more stable than the native fat globule membrane. For homogenization pressures above 4 MPa, no plasticization was observed. However, freezing and thawing counteract mild homogenization, so minor oiling off occurs, and flowability is enhanced. Extending frozen storage time up to 3 months did not result in more oiling off or higher tan δ values. Moreover, there was no significant effect between the two freezing methods. In conclusion, freezing and frozen storage for up to 3 months is a valid method to preserve cheese curd as techno-functional properties are regained after thawing.

Physical and microbiological quality and oxidative stability in different storage periods of Angus-Nellore heifer meat in an integrated livestock-forest system

This study aimed to evaluate the physical and microbiological quality as well as the oxidative stability of meat stored frozen (30, 60, 90, 180, and 360 days) and obtained from Angus-Nelore heifers kept in a conventional system (CS; no shade available) and Integrated Livestock-Forest (ILF-1L and ILF-3L). Forty-eight ½ Nellore ½ Angus heifers with an average initial weight of approximately 276.70 ± 20.1 kg and an average age of nine months were distributed across a randomized block design with three treatments and four replicates. After slaughter, the Longissimus thoracis muscle was collected from each carcass for pH, lipid oxidation, meat color, and microbiological analyses. The physical and microbiological quality and oxidative stability of the meat were not affected by the tree component present in the pasture. Regarding the duration of frozen storage, it was found that the pH, meat color (a*, b*, C*, H*, O/M), and lipid oxidation increased as the period of storage increased (P&lt;0.05). The physical and microbiological quality, as well as the oxidative stability of the meat, was not affected by the tree component present in the pasture. However, the meat changed as the frozen storage time increased.

Effects of Long-Term Cryopreservation on the Transcriptomes of Giant Grouper Sperm.

The giant grouper fish (Epinephelus lanceolatus), one of the largest and rarest groupers, is a fast-growing economic fish. Grouper sperm is often used for cross-breeding with other fish and therefore sperm cryopreservation is important. However, freezing damage cannot be avoided. Herein, we performed a transcriptome analysis to compare fresh and frozen sperm of the giant grouper with frozen storage times of 0, 23, 49, and 61 months. In total, 1911 differentially expressed genes (DEGs), including 91 in El-0-vs-El-23 (40 upregulated and 51 downregulated), 251 in El-0-vs-El-49 (152 upregulated and 69 downregulated), and 1569 in El-0-vs-El-61 (984 upregulated and 585 downregulated), were obtained in the giant grouper sperm. DEGs were significantly increased at 61 months of cryopreservation (p < 0.05). GO and KEGG enrichment analyses of the DEGs revealed significant enrichment in the pilus assembly, metabolic process, MAPK signaling pathway, apoptosis, and P53 signaling pathway. Time-series expression profiling of the DEGs showed that consistently upregulated modules were also significantly enriched in signaling pathways associated with apoptosis. Four genes, scarb1, odf3, exoc8, and atp5f1d, were associated with mitochondria and flagella in a weighted correlation network analysis. These genes may play an important role in the response to sperm freezing. The experimental results show that long-term cryopreservation results in freezing damage to the giant grouper sperm. This study provides rich data for studies of the mechanism underlying frozen fish sperm damage as well as a technical reference and evaluation index for the long-term cryopreservation of fish sperm.

Pasting, thermal and structural changes of part‐baked bread prepared under freezing conditions

SummaryIn frozen part‐baked bread technology, starch is influenced by various processing factors. This study aimed to investigate the effect of part‐baking time, freezing rate and frozen storage time on pasting, thermal and structural properties of part‐baked bread. Wheat dough was part‐baked for 0, 3 or 6 min and frozen at −20 °C using two freezing rates: slow (0.15 °C min−1) or fast (1.45 °C min−1). Next, samples were stored in frozen conditions for 56 days and analysed every 14 days for starch damage, pasting properties, thermal and X‐ray analysis. The level of damaged starch increased with 3 min (69.3%), and 6 min (88.8%) of part‐baking time for both freezing rates compared to no part‐baked. In pasting analyses, peak viscosity decreased 27.3% and 38.4% for 3 and 6 min of part‐baking time, respectively, at 0 days of frozen storage; however, this tendency was observed for all frozen storage time. The gelatinisation enthalpy (ΔHg) decreased as part‐baking time increased, showing the maximum reduction at 6 min of part‐baked (94.9%). In X‐ray diffraction analyses at 3 and 6 min of part‐baking, the intensity of the signal increased 4.4% and 10.9%, respectively, probably due to the starch gelatinisation. These results can serve as a valuable guide for developing strategies to enhance the quality of part‐baked bread and improve production performance.

Cryoprotective effect of epigallocatechin gallate replacing sucrose on Hypophythalmichthys molitrix surimi during frozen storage.

The present study aimed to investigate the cryoprotective effect of epigallocatechin gallate (EGCG) replacing sucrose on surimi during frozen storage. Substitution or partial substitution of 0.1% EGCG for sucrose (1.5%) was added to surimi, and the surimi samples without and with commercial cryoprotectants (4% sucrose and 4% sorbitol) were used as the control group. The results obtained suggest that, with the increase in frozen storage time, the structural performance of surimi protein gradually weakened (e.g. the decrease in the surface hydrophobicity, the increase in the total sulfhydryl and solubility, and the protein myosin heavy chain bands became shallow) and surimi gel quality gradually deteriorated (e.g. the decrease in water-holding capacity, gel strength and all texture profile attributes). However, compared with the other three group surimi samples during the frozen period, the surimi proteins with partial replacement of sucrose by EGCG had a higher total sulfhydryl group content and solubility of proteins, as well as lower surface hydrophobicity of protein, suggesting that the addition of EGCG as a partial substitute for sucrose can enhance the antifreeze ability of surimi. Meanwhile, the surimi gel with the partial replacement of sucrose by EGCG had a higher water retention capacity, gel strength and texture attributes (e.g. hardness, springiness, cohesiveness, chewiness, and resilience), indicating that the addition of EGCG as a partial substitute for sucrose can inhibit the deterioration of surimi gel quality. Overall, EGCG partially replacing sucrose can play an alternative cryoprotectant with a lower sweetness to prevent the quality of surimi from deteriorating. © 2024 Society of Chemical Industry.

Quality change in Bombay duck (Harpadon nehereus) surimi during frozen storage using different freezing methods.

To inhibit the quality deterioration caused by the frozen storage of surimi products, this work investigated the effect of freezing methods, including raw-freezing-setting-heating, raw-setting-freezing-heating, and raw-setting-heating-freezing, on quality changes in surimi gel. The moisture loss, physical-chemical properties, and protein structure conformation of surimi gel derived from Bombay duck (BD) were assessed following frozen storage periods of 20, 40, and 60 days. The findings suggest that the raw-setting-heating-freezing method yielded optimal surimi gel properties with extended frozen storage time. Employing this approach led to a reduction in thawing loss, while cooking loss remained constant. After 60 days of frozen storage, the hardness exhibited an initial increase followed by a subsequent decrease, and water-holding capacity increased to 68.2%. Notably, the impact on surimi gel during the late stage of frozen storage was more pronounced throughout the formation of ice crystals, resulting in decreased disulfide bond content. Scanning hematoxylin-eosin (HE) staining slices of samples following thawing and heating demonstrated that the raw-setting-heating-freezing method could better resist the effect of ice crystals in frozen storage period on surimi tissue, while the gel on setting process could delay the erosion imposed on by ice crystals during frozen storage. This study provides a scientific foundation for the industrialization on frozen BD surimi products.

Moisture, rheology and structure of deacetylated konjac glucomannan-treated dough and the performance of steamed bread under frozen storage

Deacetylated konjac glucomannan (Da) is utilized to enhance the quality of wheat products. This study investigated the impact of Da1, Da2 and Da3 (with deacetylation degrees of 23.62, 59.60 and 95.53%, respectively) as well as frozen storage times on the moisture, rheological and structural characteristics of dough, as well as the quality of the resulting steamed bread. The findings indicated that Da played a significant role in improving the freezable water content, moisture distribution and rheology of the dough. Especially, in the 1.5% Da2 group, the improvement effect on dough was most significant and the gluten network structure was the most compact. Moreover, Da exerted a positive influence on the quality of the steamed bread with 1.5% Da2 showing the most significant improvements. Correlation analysis revealed a negative relationship between the dough's freezable water content and its rheological properties, bound water content and disulfide bonds. These findings provide a theoretical foundation for the industrial application of Da in wheat-based products.

Quality changes of whitespotted conger (Conger myriaster) based physicochemical changes and label-free proteomics analysis during frozen storage

Whitespotted conger (Conger myriaster) muscle proteins were susceptible to oxidative denaturation during frozen storage. The objective of this study was to investigate the alterations in quality through physicochemical analysis and proteomics after whitespotted conger stored at temperatures of −18 °C and −60 °C. The microstructural observation revealed the noticeable variations such as increased interstitial space and fractured muscle fibre with extension of frozen storage time, and the muscle fibre of whitespotted conger stored at −60 °C were more intact than those stored at −18 °C. The raised TVB-N value indicated that the freshness of whitespotted conger decreased during 120-day frozen storage period. Analysis of myofibrillar protein content and SDS-PAGE demonstrated that compared to −18 °C, lower storage temperature (−60 °C) could better maintain the structure of whitespotted conger muscle by inhibiting protein degradation and oxidation. To reveal the mechanism of protein degradation, label-free quantitative proteomic analysis was performed through LC-MS/MS. The structural proteins including domain-associated proteins and actin-related proteins were up-regulated during frozen storage, but the phosphoglycerate kinase, phosphoglycerate mutase, and fructose-bisphosphate aldolase were down-regulated. Storage at −18 °C accelerated the up- or down-regulation of those differentially abundant proteins. According to KEGG analysis, up- or down-regulated pathways such as glycolysis/gluconeogenesis, carbon metabolism, biosynthesis of amino acids, and calcium signalling pathway mainly accounted for the protein degradation and quality reduction of whitespotted conger at low temperature. These results provided a theoretical basis for improving the quality stability of whitespotted conger during frozen storage.

The Physicochemical Properties and Melting Behavior of Ice Cream Fortified with Multimineral Preparation from Red Algae.

Ice cream is a popular frozen food consumed worldwide throughout the year. However, as a thermally unstable product, it requires proper cold chain management. Thermal fluctuations alter the physicochemical properties of ice cream and reduce its quality. This study was conducted to evaluate the physicochemical and sensory properties of ice cream containing different amounts (0.5; 0.8; 1.0%) of a multimineral preparation from Atlantic red algae. The effect of thermal shock on the quality of ice cream after preparation and 90 days of frozen storage was studied. The addition of a multimineral component slightly increased the freezing and glass transition temperatures of the ice cream. The overrun of the ice cream ranged from 48.55 to 52.78% and decreased with the frozen storage time, but the samples with 0.8 and 1.0% mineral content had the most stable overrun in terms of storage time and thermal fluctuations. Ice cream stored for both 7 and 90 days showed a similar melting behavior, although a shift in the melting curves was observed after long frozen storage. The samples exposed to the thermal treatment had lower melting rates by 39.2-59.9% and 55.2-65.4% for 7-day and 90-day stored ice cream, respectively. The hardness parameters of the ice cream did not change significantly under the conditions applied, so the fragility of the ice cream and its fluffiness did not seem to be affected. The organoleptic evaluation showed that ice cream with a mineral content of 0.8% was the most acceptable in terms of taste, texture, and overall acceptability. The applied mineral and sucrose content ratios did not alter the main physicochemical and organoleptic parameters, but significantly affected the nutrient density of the ice cream.

Effects of Frozen Storage Time, Thawing Treatments, and Their Interaction on the Rheological Properties of Non-Fermented Wheat Dough.

In this study, the effects of frozen storage time, thawing treatments, and their interaction on the rheological properties of non-fermented dough were evaluated. Texture profile analysis (TPA), rheological measurements, including strain/frequency sweep, and creep-recovery measurement were applied to the dough. Compared with unfrozen fresh dough, the frozen storage time (S) and thawing treatment (T) influenced almost all indicators significantly, and their mutual effects (S × T) mainly affected the hardness and springiness. Frozen time was the main factor resulting in the destruction of non-fermented dough during the thawing treatments. Moreover, refrigerator thawing (4 °C) produced a dough with minimal changes in the rheological properties, regardless of the frozen storage time. Meanwhile, microwave thawing resulted in lower G' and lower zero shear viscosity (η0) values, as well as higher maximum creep compliance (Jmax) and hardness values. Moreover, the difference between the three thawing treatments was exacerbated after 30 days of frozen storage. SEM images also showed that long-term frozen storage combined with microwave thawing seriously destroyed the rheological properties, structural stability, and inner microstructure of the dough.

Effect of raw material frozen storage on physicochemical properties and flavor compounds of fermented mandarin fish (Siniperca chuatsi)

Frozen mandarin fish (MF) is utilized for preparation fermented MF. However, how raw material (RM) affects the quality and flavor of fermented MF is unclear. This study investigated the impact and mechanism of RM frozen storage on the microstructure, texture, water distribution, and flavor of fermented MF by light microscopy, texture profile analysis, low-field nuclear magnetic resonance, gas chromatography-ion mobility spectrometry, and multivariate analysis. With increasing RM frozen storage time, both frozen MF and frozen-based fermented MF decreased in muscle fiber density while increased in muscle fiber diameter. Additionally, RM frozen storage exhibited a significant impact on the water distribution of frozen MF, while no obvious effect on that of frozen-based fermented MF. Seven odorant (2-methyl-1-propanol, 3-hydroxy-2-butanone, 2,3-butanedione, hexanal-D, ethyl acetate-D, 3-pentanone, and acetone) were shown as potential markers to distinguish fermented MF. This study could provide a theoretical basis for the production of high-quality frozen-based fermented MF.

Influence of Different Previous Frozen Holding Periods on the Canned Fish Quality.

The combined effects of thermal processing (i.e., sterilisation treatment) and the prior frozen storage time (3 or 6 months at -18 °C) on the quality loss in canned Atlantic horse mackerel (Trachurus trachurus) were determined. Thus, the sterilisation step led to a remarkable (p < 0.05) formation in the canned fish muscle of fluorescent compounds, free fatty acids (FFAs), and trimethylamine and an increase in the L* and b* colour parameters; meanwhile, a decrease (p < 0.05) in the total ω3 FA/total ω6 FA ratio and the a* colour value were detected. The prior frozen storage period led to an increased (p < 0.05) lipid oxidation (peroxide, thiobarbituric acid reactive substance, and fluorescent compound formation) and hydrolysis (FFA formation) development and to increased L* and b* colour values in the corresponding canned samples; additionally, a lower (p < 0.05) polyene index and phospholipid content were observed in canned fish previously subjected to frozen storage. In most indices, physico-chemical changes related to quality loss were found to be higher if the previous storage period was increased. According to the marked effects of the sterilisation step and the prior frozen storage period, the optimisation of such processing conditions is recommended to maximise the quality of canned horse mackerel.

Cysteamine Eye Drops in Hyaluronic Acid Packaged in Innovative Single-Dose Systems, Part II: Long-Term Stability and Clinical Ocular Biopermanence.

Cystinosis is a rare genetic disorder characterized by the accumulation of cystine crystals in several tissues and organs causing, among others, severe eye symptoms. The high instability of cysteamine eye drops makes it difficult to develop formulations with an acceptable shelf life to be prepared in hospital pharmacy departments. Previously, a new compounded formulation of cysteamine eye drops in hyaluronic acid (HA) packaged in innovative single-dose systems was developed. Long-term stability at -20 °C of this formulation was studied considering the content of cysteamine, pH, osmolality, viscosity, and microbiological analysis. The oxygen permeability of single-dose containers was also studied and an ocular biopermanence study was conducted in healthy volunteers measuring lacrimal stability and volume parameters. Data confirm that cysteamine concentration remained above 90% for 120 days, all parameters remaining within the accepted range for ophthalmic formulations. The permeability of the containers was reduced over time, while ocular biopermanence was maintained despite the freezing process and storage time. 0.55% cysteamine hydrochloride formulation in HA and packaged in single-dose containers preserved at -20 °C is stable for 120 days protected from light, presenting high potential for its translation into clinical practice when commercial presentations are not available.

Effects of frozen of marula fruits (Sclerocarya birrea) on chemical, antioxidant activities, and sensory properties of marula fruit juice

This study determined the effects of frozen storage on physicochemical, phenolic content and antioxidant activities of fruit juice extracted from frozen marula fruits. The marula fruits were frozen for zero to eight weeks after which the frozen marula fruits were thawed between 10 and 12 h and the juice extracted manually. There was 36.35% decrease in vitamin C content of the juice, 36.70% decrease in TPC, 46.50% decrease in FRAP and 53.22% decrease in TFC. The colour of the marula fruit juice decreases with increase in frozen storage time and the marula fruit juice extracted from unfrozen marula fruit was score highest in all the sensory properties evaluated. Although, freezing is one of the best preservative methods of fruits, the type of freezer used for the freezing process determines the nutritional value of the fruits and the juice. A home freezer may not be good to store marula fruits.

Investigation of the changes in gelation properties of hydroxypropyl distarch phosphate-surimi gel under different gelation-freezing treatments.

Frozen storage often leads to quality deterioration of surimi-based products. At present, most of the research focuses on improving the quality of surimi products by adding cryoprotectants, and there are few studies available on preparation technology. Therefore, the effects of different gelation-freezing treatments, high temperature heating-freezing treatment (HF), low temperature heating-high temperature heating-freezing treatment (LHF) and low temperature heating-freezing-high temperature heating treatment (LFH) on the quality changes of surimi gels containing hydroxypropyl distarch phosphate (HPDSP) during frozen storage were investigated. With the extension of frozen storage time, the quality of surimi gel in all groups decreased, but the quality of surimi gel with HPDSP was better than that of surimi gel without HPDSP. Compared with HF and LHF, the change range of breaking force, hardness, gumminess, whiteness and disulfide bond content of HPDSP-surimi gel treated with LFH was the least during the frozen storage. In the reheating process of LFH, HPDSP could absorb the water lost during freezing. Therefore, the change in the transverse relaxation time of HPDSP-surimi gels treated with LFH was smaller, with more immobile water and less free water and P22 of 96.81% and P23 of 0% at 16 weeks. In addition, the breaking deformation, cohesiveness, resilience, springiness and protein composition of surimi gels with and without HPDSP treated with HF, LHF and LFH did not change significantly during frozen storage. The combination of LFH and HPDSP could effectively reduce the quality change of surimi gel during frozen storage. © 2023 Society of Chemical Industry.

Inactivation of Salmonella, Shiga Toxin-producing E. coli, and Listeria monocytogenes in Raw Diet Pet Foods Using High-Pressure Processing

Pet food formulated with raw meat can pose health risks to pets and humans. High-pressure processing (HPP) was evaluated to achieve a 5-log reduction ofSalmonella,E. coliSTEC, andL. monocytogenesin commercial raw pet foods and maintain a 5-log reduction throughout post-HPP storage.Three formulation types that varied in the amounts of striated meat, organ meat, bone, seeds, and other ingredients (fruits, vegetables, and minor ingredients) designated as A-, S-, and R-formulations were used.Eight raw diet pet foods, consisting of three beef formulations (A-, S- and R-Beef), three chicken formulations (A-, S-, and R-Chicken), and two lamb formulations (A- and S-Lamb), were inoculated with 7 log CFU/g cocktails ofSalmonella,E. coliSTEC orL. monocytogenes, HPP at 586 MPa for 1–4 min, and stored refrigerated (4°C) or frozen (−10 to −18°C) for 21 days with microbiological analyses at various time intervals.A- formulations (20–46% meat, 42–68% organs, 0.9–1.3% seeds, and 10.7–11.1% fruits, vegetables, and minor ingredients) inoculated withSalmonellaand treated at 586 MPa for at least 2 min achieved a 5-log reduction 1 day post-HPP and maintained that inactivation level during frozen storage. A- and S-formulations inoculated withE. coliSTEC and treated at 586 MPa for at least 2 min achieved a 5-log reduction from day 6 of frozen storage.L. monocytogeneswas more HPP resistant thanSalmonellaandE. coliSTEC.S-formulations containing chicken or beef and stored frozen post-HPP had lower inactivation of L. monocytogenes compared to A-formulations containing chicken or beef. S-Lamb had higher frozen storage inactivation (5.95 ± 0.20 log CFU/g) compared to chicken (2.52 ± 0.38 log CFU/g) or beef (2.36 ± 0.48 log CFU/g). HPP coupled with frozen storage time was effective in achieving and maintaining a 5-log reduction ofSalmonellaandE. coliSTEC whileL. monocytogeneswas more resistant and requires further optimization to achieve a 5-log reduction.

Impact of frozen storage on some functional properties and sensory evaluation of goose meat

The objective of this study was to investigate the changes in the functional properties (pH, water holding capacity [WHC], water binding capacity [WBC], cooking losses [CL], defrosting losses [DL]), color parameters (L*, a*, b*, C, h°, ΔE), and sensory evaluation of breast (BM) and leg (LM) muscles from 17-wk-old female White Kołuda geese packaged in a vacuum and stored in frozen conditions at -20°C. During 17 wk, the geese were fed ad libitum on the same complete feed. The samples (18 BM and 18 LM) from the right part of the carcasses were stored for 30, 90, 80, 270, and 365 d. The changes in functional properties were established using a standard method used in the meat industry, according to Wierbicki et al. (1962), Grau and Hamm (1953), and CIE, (1986). Sensory evaluation was established according to defined parameters in PN-ISO 8586-2:2008. The time of frozen storage affected the decrease in WHC and WBC of BM and LM. Moreover, the LM can be characterized by a higher WHC and WBC compared to the values in the BM. It was established that CL and DL, which are the critical quality indicators, negatively increased in BM and LM during frozen storage. Considering the sensory evaluation and L*, a*, b*, C, it was established that changes in BM and LM during frozen storage were unfavorable. The scores given for smell, taste, consistency, and general appearance, as also L*, a*, and b* parameters decreased significantly during frozen storage. In addition, BM received lower scores for general appearance (at 180th and 270th day), and L* (in all frozen storage), than LM. BM and LM characterized the parameter ΔE in the range of 0.44 to 1.45, which allowed us to conclude that slight color differences were visible in these muscles (<2). Based on the study, it can be suggested that the optimal frozen storage time for BM and LM should not be longer than 180 d.

Impact of glucose oxidase on characteristics of corn dough with different frozen storage times

SummaryWe have studied the impact of different concentrations of GOX on corn doughs' processing characteristics and protein structure. The doughs were frozen for different periods, and the quality of their products, like corn tortillas, was studied. The results showed that adding GOX attenuated the adverse effects of ice crystals produced during the freezing period and improved the dough's viscoelasticity and low‐temperature stability. In addition, GOX further enhanced its water‐holding capacity, limited water mobility, and re‐established the dough's secondary structure. Furthermore, the results demonstrated that GOX improved the texture and delayed the staling rate of corn tortillas prepared with fresh and frozen corn dough. We further concluded that 100 mg kg−1 of GOX exhibited the best improvement effect on the corn dough characteristics and quality of the produced tortillas.