Texture Softening Research Articles

Advancing Fruit Preservation: Ecofriendly Treatments for Controlling Fruit Softening

Textural softening is a major factor that limits the storage potential of fruit. Fresh produce markets incur severe financial losses due to excessive fruit softening. The application of preservation strategies aimed at mitigating fruit softening is crucial for optimising the marketability of fruit. Proposed preservation strategies include ecofriendly treatments, namely, hexanal, edible coatings, heat treatments, ozone and UV-C irradiation. These treatments optimise firmness retention by targeting the factors that affect fruit softening, such as ethylene, respiration rates, enzymes and pathogens. This review discusses the mechanisms by which ecofriendly treatments inhibit fruit softening, providing insights into their effect on ethylene biosynthesis, cell wall metabolism and disease resistance. Although ecofriendly treatments offer a promising and sustainable approach for delaying fruit softening, the optimisation of treatment application protocols is needed to improve their efficacy in retaining fruit firmness. Studies reporting on the molecular mechanisms by which ecofriendly treatments inhibit fruit softening are limited. Future studies should prioritise proteomic and transcriptome analyses to advance our understanding of the underlying molecular mechanisms by which ecofriendly treatments delay the fruit-softening process.

Endogenous Proteases in Sea Cucumber (Apostichopus japonicas): Deterioration and Prevention during Handling, Processing, and Preservation.

The sea cucumber is an essential nutrient source and a significant economic marine resource associated with successful aquaculture. However, sea cucumbers are highly susceptible to autolysis induced by endogenous protease after postmortem, and the phenomenon of body wall "melting" occurs, which seriously affects the food quality of products and the degree of acceptance by consumers. To satisfy the growing demand for fresh or processed sea cucumbers, we must clarify the autolysis mechanism of sea cucumbers and the methods to achieve autolysis regulation. In this paper, the factors leading to the quality deterioration and texture softening of sea cucumbers are reviewed, with emphasis on enzymatic characteristics, the autolysis mechanism, the effects of autolysis on the physicochemical properties of the body wall of the sea cucumber, and the development of potential natural protease inhibitors. We aim to provide some reference in future preservation and processing processes for sea cucumbers, promote new processing and preservation technologies, and advance the sea cucumber industry's development.

Cold plasma treatment delays the texture softening of apricot fruit through PAPL-PL-pectin changes

Apricot, a forest fruit with distinct characteristics, has witnessed a continuous expansion of its market scale over the years. However, the high loss rate caused by fruit texture softening poses a significant challenge to the development of the apricot industry. The effect of cold plasma treatment on the texture was investigated. The findings revealed that compared to the control group, the firmness of apricot fruit increased by 49%, 31%, and 30% after treatment for 20, 40, and 60 s, respectively. Applying an optimal cold plasma treatment (20–40 s) can effectively inhibit the degradation of pectin component branches, thereby delaying the increase in water-soluble pectin (WSP) and iron - soluble pectin (ISP) content, reducing the decline in covalent - soluble pectin (CSP) content, ultimately enhancing fruit firmness and extending the storage period of apricot. RNA-seq results revealed the involvement of pectin decomposition mediated by pectin lyase (PL) in the process of texture softening of apricot fruit, with a key role played by the pectin lyase gene (PaPL). These findings not only enrich the mechanism of texture softening of apricot fruit, but also provide valuable insights for utilizing cold plasma in post-harvest preservation of apricot fruit.

Effect of the whey protein isolate-pectin bilayer emulsion system on the textural properties and oil release characteristics of room-temperature stored processed cheese

Processed cheeses stored at room temperature exist some texture defects, such as texture softening and free oil release. The emulsion obtained by pre-emulsifying butter with whey protein isolate (WPI) can significantly improve the texture softening, but it was unable to mitigate the release of free oil during storage. Therefore, in this study, a WPI-pectin bilayer emulsion system was manufactured and applied in the production of processed cheese. The effects of adding the WPI-pectin bilayer emulsion system on the texture and functional characteristics of processed cheese during storage were investigated. The results of the study showed that the WPI-pectin bilayer emulsion system significantly improved the texture softening and free oil release characteristics of the room-temperature stored (RTS) processed cheese. Scanning electron microscopy revealed that the addition of the WPI-pectin bilayer emulsion system increased the uniformity of cheese microstructure and the number of small free fat pools after pre-emulsification. This study provided a method for improving the texture defects of RTS processed cheese, which is important for the processing and promotion of RTS processed cheese.

Temperature-driven divergence in molecular distribution and microbial invasion and the associated texture softening during dual-phase fermentation of Paocai

Temperature is an important driving force that shapes the texture of fermented vegetables through driving the molecular distribution and microbial invasion between the liquid phase (brine) and the solid phase (vegetables) during fermentation. The objective of this study was to investigate the texture softening by investigating firmness, microstructure, physicochemical properties, molecular distribution and microbial community between brine and vegetables of Paocai as affected by fermentation temperatures of 10 °C, 20 °C and 30 °C. Results demonstrated that, compared with 10 °C and 30 °C, 20 °C attenuated softening of Paocai by restraining microbial invasion and suppressing pectinolysis. Moreover, at 20 °C, a balanced molecular distribution and microbial community were achieved between vegetables and brine, thus accomplishing acid-production fermentation. By contrast, 10 °C and 30 °C promoted nonfermentative microbial genera, retarding fermentation. This study provided an understanding of the divergent influence of temperature on quality formation of fermented vegetables during fermentation.

Effects of different freezing methods on muscle qualities and myofibrillar protein properties of red drum (Sciaenops ocellatus) during storage

The freezing of aquatic products without causing significant changes in quality is recently attracting much attention. In this study, the effects of air freezing (AF, -20 °C), blast freezing (BF, -35 °C), liquid nitrogen freezing (LNF), and immersion freezing (IF, -35 °C) by 20 % ethanol, 20 % propylene glycol, 10 % glycerol, and 10 % sodium chloride aqueous solutions, respectively, on muscle qualities and myofibrillar protein properties of the red drum were investigated. The results indicated that the freezing rate of IF was 2.66 cm/h, which was 6.33 times higher than that in AF groups. Compared with AF and BF, the ice crystals were smaller and more uniformly shaped, with properties of lower water migration and less texture softening after cryogenic liquid freezing of IF and LNF group aquatic products. Immersion freezing showed the same superiority in maintaining the freshness of fish fillets and retaining the protein structure as liquid nitrogen storage. Overall, IF has similar effects to LNF in maintaining muscle qualities and myofibrillar protein properties. This study describes a new freezing method that uses 20 % ethanol, 20 % propylene glycol, 10 % glycerol, and 10 % sodium chloride aqueous solutions as immersion freezing medium. The multi-compound freezing medium has the potential to be used for the freezing of aquatic products.

Comparison of Fruit Texture and Storage Quality of Four Apple Varieties.

Fruit texture and storage properties of various apple varieties exhibit significant variation. The rate of fruit softening post-harvest plays a crucial role in determining fruit quality and shelf life. This research utilized four apple varieties as test subjects to investigate the internal factors influencing fruit texture changes among different varieties. By monitoring changes in relevant physiological indicators during the post-harvest texture softening process, the study examined fruit quality, cell wall material content, hydrolase activity, and gene transcription levels during storage of 'Orin', 'RX', 'RXH', and 'Envy' apples. Initial fruit softening was primarily linked to heightened post-harvest fruit respiration intensity, ethylene production, and rapid amylase activity. Subsequent softening was associated with increased activity of water-soluble pectin (WSP), cellulose (CEL), and other hydrolases. With the extension of the storage period, the fruit cells of the four varieties became more loosely arranged, resulting in larger intercellular gaps. Variations in WSP and cellulose content, CEL activity, and relative expression of Mdβ-gal were observed among the different apple varieties, potentially accounting for the disparities in fruit texture.

The inhibition mechanism of PostbioYDFF-3 on quality deterioration of refrigerated grass carp fillets from the perspective of endogenous enzyme and microorganisms changes

The protective mode of PostbioYDFF-3 (referred to as postbiotics) on the quality stability of refrigerated fillets was explored from the aspects of endogenous enzyme activity and the abundance of spoilage microorganisms. Compared to the control group, the samples soaked in postbiotics showed significant reductions in TVC, TVB-N and TBARS values by 39.6%, 58.6% and 25.5% on day 5, respectively. In addition, the color changes, biogenic amine accumulation and texture softening of the fish fillets soaked in postbiotics were effectively suppressed. Furthermore, the activity of endogenous enzyme activities was detected. The calpain activities were significantly inhibited (p < 0.05) after soaking in postbiotics, which declined by 23%. Meanwhile, high throughput sequencing analysis further indicated that the growth of spoilage microorganism such as Acinetobacter and Pseudomonas were suppressed. Overall, the PostbioYDFF-3 was suitable for preserving fish meat.

Synergistic mechanism of steam blanching and freezing conditions on the texture of frozen yellow peaches based on macroscopic and microscopic properties.

Freezing and blanching are essential processing steps in the production of frozen yellow peaches, inevitably leading to texture softening of the fruit. In this study, the synergistic mechanism of stem blanching, freezing conditions (-20°C, -40°C, -80°C, and liquid nitrogen [-173°C]), and sample sizes (cubes, slices, and half peaches) on macroscopic properties of texture, cellular structure, and ice crystal size distribution of frozen yellow peaches were measured. Blanching enhanced the heat and mass transfer rates in the subsequent freezing process. For nonblanched samples, cell membrane integrity was lost at any freezing rate, causing a significant reduction in textural quality. Slow freezing further exacerbated the texture softening, while the ultra-rapid freezing caused structural rupture. For blanched samples, the half peaches softened the most. The water holding capacity and fracture stress were not significantly affected by changes in freezing rate, although the ice crystal size distribution was more susceptible to the freezing rate. Peach cubes that had undergone blanching and rapid freezing (-80°C) experienced 4% less drip loss than nonblanched samples. However, blanching softened yellow peaches more than any freezing conditions. The implementation of uniform and shorter duration blanching, along with rapid freezing, has been proven to be more effective in preserving the texture of frozen yellow peaches. Optimization of the blanching process may be more important than increasing the freezing rate to improve the textural quality of frozen yellow peaches.

Ultrasonic monitoring of softening in solid foods during in-vitro gastric digestion

This study aims to evaluate the feasibility of using non-destructive ultrasound to monitor textural softening in potato and cheese during in vitro gastric digestion. Textural measurements were taken after different digestion times (5, 10, 15, 20, 25, 30, 60, 90, and 120 min) at 37 °C, while in vitro digestion was non-destructively monitored using ultrasound in through-transmission mode.The textural softening resulted in a substantially greater variation in hardness, ranging from 0.418 to 1.241 N for potato and from 0.200 to 0.534 N for cheese. Meanwhile, the ultrasonic velocity increased during gastric digestion from 745 ± 106.6 m/s to 1342.9 ± 131.5 m/s in potato and from 1377.4 ± 3.8 m/s to 1502.8 ± 4.6 m/s in cheese. Both the softening and velocity increase were attributable to the compositional variation occurring within the food structure due to gastric fluid diffusion into the food matrix. The Weibull model kinetic parameter “k” indicated that potato exhibited a higher softening rate than cheese, due to a faster gastric fluid migration. This was also evidenced by the effective diffusivity of gastric fluid (Deff) obtained by modeling the evolution of the ultrasonic velocity during digestion (Deff, potatõ2.5 Deff, cheese). A noticeable relationship was found between the softening of both food matrices and the change in the ultrasonic wave velocity. Additionally, it should be highlighted that the measurement of the ultrasonic velocity by ultrasound presented a lower degree of variability than instrumental texture assessment. Therefore, ultrasound proves to be an accurate technique for the on-line monitoring of textural changes in foods during in vitro digestion. This non-destructive approach provides a powerful instrumental tool in the design of new products with enhanced nutritional properties by better monitoring how in vitro digestion affects their mechanical properties.

Banana MabHLH28 positively regulates the expression of softening-related genes to mediate fruit ripening independently or via cooperating with MaWRKY49/111.

Texture softening is a physiological indicator of fruit ripening, which eventually contributes to fruit quality and the consumer's acceptance. Despite great progress having been made in identification of the genes related to fruit softening, the upstream transcriptional regulatory pathways of these softening-related genes are not fully elucidated. Here, a novel bHLH gene, designated as MabHLH28, was identified because of its significant upregulation in banana fruit ripening. DAP-Seq analysis revealed that MabHLH28 bound to the core sequence of 'CAYGTG' presented in promoter regions of fruit softening-associated genes, such as the genes related to cell wall modification (MaPG3, MaPE1, MaPL5, MaPL8, MaEXP1, MaEXP2, MaEXPA2, and MaEXPA15) and starch degradation (MaGWD1 and MaLSF2), and these bindings were validated by EMSA and DLR assays. Transient overexpression and knockdown of MabHLH28 in banana fruit resulted in up- and down-regulation of softening-related genes, thereby hastening and postponing fruit ripening. Furthermore, overexpression of MabHLH28 in tomato accelerated the ripening process by elevating the accumulation of softening-associated genes. In addition, MabHLH28 showed interaction withMaWRKY49/111 and itself to form protein complexes, which could combinatorically strengthen the transcription of softening-associated genes. Taken together, our findings suggest that MabHLH28 mediates fruit softening by upregulating the expression of softening-related genes either alone or in combination with MaWRKY49/111.

Cold Formability of Twin-Roll Cast, Rolled and Annealed Mg Strips

This study investigates the cold formability of twin-roll cast and rolled magnesium strips, specifically focusing on AZ31 and ZAX210 alloys. The aim is to assess the suitability of these alloys for various forming processes. The mechanical properties and formability characteristics of the strips were thoroughly examined to provide insights into their potential applications in transportation industries such as automotive and aerospace. The AZ31 and ZAX210 alloys were subjected to twin-roll casting and rolling processes to produce thin strips. The resulting strips were then evaluated for their cold formability. The results indicate that both alloys exhibit favourable cold formability. The ZAX210 alloy, in particular, demonstrates medium strengths with an average tensile strength of approximately 240 MPa at room temperature. The 0.2% proof stress values range between 136 MPa and 159 MPa, depending on the sampling direction. The total elongation values vary from 28% in the transverse direction to 32% at a 45° angle, indicating excellent ductility. Comparing the two alloys, the AZ31 alloy shows higher strengths due to its higher aluminium content. However, it also exhibits a more pronounced directional dependence of mechanical properties due to the formation of a strong basal texture during hot rolling. The transverse direction experiences reduced total elongation compared to the rolling direction, achieving only about 50% of the total elongation. The average Erichsen Index recorded for AZ31 and ZAX210 strips were 4.9 mm and 7.1 mm, respectively. The ZAX210 strip displays superior formability, which can be attributed to the fine-grained microstructure and the texture softening resulting from the weakening of the basal texture intensity and the splitting of the basal pole towards the rolling direction. In conclusion, the investigated twin-roll cast, rolled and annealed AZ31 and ZAX210 magnesium strips exhibit promising cold formability characteristics. The findings of this study contribute to the understanding of their mechanical behaviour and can guide the selection and optimisation of these alloys for various forming applications.

Cell wall modifications during storage: Changes in the texture behavior of the canned yellow peach

Textural changes in canned yellow peach (CYP) soaked in a concentrated sucrose syrup that led to softening during storage were always accompanied by the depolymerization of the cell wall, as the result of the cell wall-modifying enzymes. In this study, we evaluated the changes in texture, pectin fractions (namely, WEP, CEP and AEP) and pectinase activities (namely, PME and PG) during storage. Results showed that the undoubted decrease in Gal contents of all pectin fractions (∼44.16%, ∼36.98% and ∼ 66.59% declines in WEP, CPE and AEP, respectively) were observed as well as the reduced texture properties. Specially, the hardness, chewiness and resilience of CYP dramatically decreased at the first 40 days-storage. Upon the storage, PG activities were significantly facilitated, while PME activities were markedly inhibited. Together with the results of molar mass and monosaccharide composition, sucrose syrup could promote the conversion and depolymerization in HG region of AEP fraction. Moreover, sugar ratio analysis and 13C NMR spectroscopy also illustrated the changes in pectin structures, contributing to the texture softening of CYP, which was confirmed by the gradual depolymerization and solubilization in HG regions of all the pectin fractions.

Vacuum-steam pulsed blanching: An emerging method to enhance texture softening, drying behavior and physicochemical properties of Cornus officinalis.

Vacuum steam pulsed blanching (VSPB) was employed as a novel blanching technology on Cornus officinalis to soften the tissue for subsequent coring and dehydration. The current work aims to explore its effect on mass transfer behavior, PPO inactivation, drying characteristics, physicochemical properties, antioxidant capacity, and microstructure of C. officinalis. Results showed that VSPB increased water loss, decreased solid gain, and increased weight reduction with increased blanching cycles. Besides, VSPB significantly changed physical properties and extensively reduced drying time which was attributed to the cell wall components dissolving and cell turgor pressure decreasing, also verified by observing microstructure alteration. PPO was completely denatured after blanching in 6 cycles, but phenolic compounds were still diffused or degraded. Notably, the content of flavonoids and antioxidant capacity significantly increased compared to fresh samples probably due to increased extractability caused by the disrupting cell structure. Besides, the carotenoids and ascorbic acid could be well preserved.

Effects of electron beam irradiation on protein oxidation and textural properties of shrimp (Litopenaeus vannamei) during refrigerated storage

Protein oxidation leads to changes in shrimp texture, which affects sensory profile and consumer acceptability. This study aimed to evaluate the impact of electron beam irradiation (EBI) on protein oxidation and textural properties of Litopenaeus vannamei during refrigerated storage. Results revealed that EBI treatment and storage increased the protein oxidation level of shrimps. Shrimps irradiated with ≥ 7 kGy exhibited remarkably higher (P < 0.05) reactive oxygen species, turbidity, and carbonyl contents, and remarkably lower (P < 0.05) Ca2+-ATPase activity, surface hydrophobicity, solubility, and total sulfhydryl contents compared to the control group (0 kGy) on the 7th day of storage. Shrimps irradiated with 3 and 5 kGy exhibited remarkably higher (P < 0.05) hardness, springiness, and chewiness compared to the control group (14.99 N, 1.26 mm, and 3.19 mJ). Collectively, suitable EBI doses of 3–5 kGy were recommended in shrimp preservation to inhibit texture softening by inducing moderate protein oxidation.

Development of thermoultrasound assisted blanching to improve enzyme inactivation efficiency, drying characteristics, energy consumption, and physiochemical properties of sweet potatoes

Thermoultrasound (USB) as a promising alternative to traditional hot water (HWB) blanching was employed to blanch sweet potatoes and its influence on enzyme activity, drying behavior, energy consumption and physiochemical properties of sweet potatoes were investigated. Results showed that successive increases in blanching temperature and time resulted in significant (p < 0.05) decreases in PPO and POD activities. Compared to HWB, USB led to more effective drying by promoting texture softening, moisture diffusion, microstructure alterations, and microchannels formation, which significantly reduced energy consumption and improved the overall quality of the dried sample. Specifically, USB at 65 °C for 15 min improved water holding capacity and ABTS, while USB at 65 °C for 30 min improved color (more red and yellow), total phenolic content, total carotenoid content, and DPPH. Unfortunately, blanching process showed detrimental effects on the amino acid composition of dried samples. Overall, the development of thermoultrasound assisted blanching for sweet potatoes has the potential to revolutionize the processing and production of high-quality sweet potato products, while also improving the sustainability of food processing operations.

Intragastric infusion of a liquid diet with low-methoxyl pectin alleviates fecal inconsistency and local proinflammatory cytokine expression in lipopolysaccharide-septic rats

ObjectiveDiarrhea interrupts enteral nutrition management in hospitalized patients with severe illnesses, such as sepsis. Pectin, a water-soluble dietary fiber, has the potential to maintain intestinal function and may reduce inflammatory reactions. The aim of this study was to demonstrate that the addition of low-methoxyl (LM) pectin to a liquid diet suppresses softening of stool texture and reduces tissue inflammatory responses in enteral nutrition management during sepsis. MethodsA fat-enriched liquid diet with LM pectin (P-EN) or a liquid diet without dietary fiber (FF-EN) was given continuously to rats through a gastric catheter. Lipopolysaccharide (LPS; 10 mg/kg) was injected intraperitoneally 24 h (study 1) and 7 h (study 2) before sacrifice. ResultsLPS injection significantly worsened fecal property scores in rats infused with FF-EN compared with the rats given P-EN in study 1. Whereas many myeloperoxidase-positive cells infiltrated the liver, and the hepatic expressions of chemokine genes were markedly elevated 24 h after LPS administration, these findings were clearly alleviated in the LM pectin-containing liquid diet group. In study 2, protein expressions of proinflammatory cytokines, such as small intestinal tumor necrosis factor-α and hepatic interleukin-1β, and interleukin-6, were significantly downregulated in the P-EN LPS group compared with the FF-EN LPS group. ConclusionsA liquid diet containing LM pectin allows enteral nutrition management with a low risk for diarrhea and reduces local inflammation under septic conditions.

Effects of proteases on textural softening and changes in physical property of harpiosquillid mantis shrimp (Harpiosquilla raphidea) during the iced storage

SummaryRapid softening of texture is a major problem associated with quality loss and consumer rejection of harpiosquillid mantis shrimp (Harpiosquilla raphidea) (HMS). Effects of endogenous proteases in muscles and digestive tract on protein degradation and softening were investigated. Scanning electron microscopic and histological images indicated drastic destruction of muscle during iced storage. Based on autolysis, maximal activity was found at pH 8.5 and 55 °C, and serine proteases including trypsin were dominant. Cathepsin B and L + B in muscle were altered throughout storage, while trypsin remained constant in HMS meat for 1–3 days. Firmness and toughness decreased and coincided with augmented degradation of myofibrillar proteins and collagen. Trypsin from the digestive tract was contaminated into the abdomen during iced storage, therefore inducing drastic hydrolysis of muscle proteins. This phenomenon caused the undesirable pasty/mushy texture associated with the loss in firmness and toughness of meat within 3 days of storage.

Phosphoproteomic insight into the changes in structural proteins of muscle architecture associated with texture softening of grass carp (Ctenopharyngodon idella) fillets during chilling storage.

Texture is an important sensory attribute of fish affected by modifications of structural proteins in muscle architecture. To investigate the changes in protein phosphorylation during texture softening of fish, the proteins of grass carp muscle after chilling storage of 0day and 6days were compared by phosphoproteomics, and their association with texture was analyzed. Totally 1026 unique phosphopeptides on 656 phosphoproteins were identified as differential. They were mainly classified as intracellular myofibril and cytoskeleton, and extracellular matrix, of which the molecular function and biological process were binding into supramolecular assembly and myofilament contraction. The concomitant dephosphorylation of kinases and assembly regulators indicated dephosphorylation and disassembly tendency of sarcomeric architecture. Correlation analysis defined the relation between texture and dephosphorylation of myosin light chain, actin, collagen and cytoskeleton. This study revealed that protein phosphorylation may affect the texture of fish muscle through regulating sarcomeric assembly of structural proteins in muscle architecture.

Investigation of the Effect of Various Ca Content on Microstructure and Mechanical Properties of As-cast ZK60 Magnesium Alloys

The effect of various Ca content on microstructure and mechanical properties of as-cast Mg-6Zn-0.5Zr (wt.%) Mg alloys with hot tensile testing at 345°C were investigated. The alloy was produced with the LPDC method [1]. Microstructural characterization as-cast alloy demonstrated that wt.% Ca content increase, grain size decreases till wt.% 0.8Ca, the further increase affects gradual change in grain size to ~60 µm at 345°C. Therefore, increase in Ca ratio from 0.4 wt% forming to strip-like Mg-Zn intermetallics at grain boundaries, Ca-Mg-Zn ternary phase at grain boundary corners. Dramatical decrease in yield and tensile strength at wt% 1.6Ca addition is 37.6 MPa and 39.7 MPa respectively which is relatively low at 345°C due to the absence of retarded DRX’ed small particles prohibited the grain growth after the TMT process. Conversely, elongation-to-fracture increases were observed as 1.26 at 345°C showing the temperature-dependent texture softening results in improvement of mechanical properties. Wear rate is also affected from wt.% Ca addition so the gradual increase up to 1.2 wt% Ca is 3.70 x 10-3 mm3/m. Similarly, a gradual increase in hardness values was obtained with Ca addition in ZK60 alloy. In this study, the effect of temperature-dependent Ca addition (wt %) on gradual enhancement in mechanical properties was observed at as-cast magnesium alloys.