Evaluation of HPCD batch treatments on enzyme inactivation kinetics and selected quality characteristics of cloudy juice from Golden delicious apples

Cold plasma processing of kiwifruit juice: Effect on physicochemical, nutritional, microstructure, rheological properties and sensory attributes

This study aimed to compare the untreated, cold plasma (CP)-optimized (30 kV/5 mm/6.7 min), CP-extreme (30 kV/2 mm/10 min), and thermally treated (TT) (90 ℃/5 min) kiwifruit juices based on the physicochemical (pH, total soluble solids (TSS), titratable acidity (TA), total color change (ΔE)), physical (particle size and rheology), microstructure (optical microscope), bioactive compounds (polyphenol, ascorbic acid, and sugar compounds), and sensory characteristics of kiwifruit juice. The pH, TSS, and TA were not significantly affected in CP and TT juice, whereas the ΔE (6.52) of TT juice lies in the range of "greatly visible." The microstructure characteristics of juice significantly changed after CP and thermal treatment. The cell and tissue disruption in CP-extreme and thermally treated juice was more than CP-optimized. The particle size of juice decreased irrespective of treatment, but the span value of CP-optimized juice was the lowest. Further, the CP treatment showed a lower consistency index, apparent viscosity, and pseudoplasticity of juice than the thermal treatment. The CP-treated juice retained bioactive and nutritional attributes more than thermally treated juice. The CP-optimized, CP-extreme, and thermal treatment reduced the sucrose content by 54, 55, and 23%, while the fructose and glucose content were increased by 17, 12, & 93%, and 17, 11 & 99%, respectively. Among the CP-treated juice, CP-optimized (71.36 mg/100g) contained a higher amount of ascorbic acid than the CP-extreme (64.36 mg/100g). Based on the similarity values in the fuzzy logic analysis, the sensory attributes of CP-optimized treated juice were superior to CP-extreme and thermal treated. PRACTICAL APPLICATION: In this era, non-thermal processing techniques are trending for retaining the nutrition and stability of juice. The old plasma (CP)-treated kiwifruit juice had better nutritional, bioactive compounds, and sensory attributes than the thermally treated juice. Further, the CP-treated juice had higher flowability and lower viscosity, making it ideal for juice processing. The conclusions drawn suggest that CP processing is a better alternative for processing kiwifruit juice than thermal processing.

Supercritical CO2 Processing of White Grape Must as a Strategy to Reduce the Addition of SO2

In winemaking, sulfur dioxide addition is the most common procedure to prevent enzymatic and microbial alterations. However, the enological industry looks for safer alternatives to preserve enological products, and high-pressure treatments with supercritical CO2 are a suitable alternative. This study evaluates the effectiveness of this process in the stabilization and preservation of white grape must, studying the influence of time, pressure, and CO2 percentage on must characteristics. In spite of the percentage of CO2 turned out to be the variable that affects the most the process, no remarkable differences were observed in pH, acidity, and color intensity between untreated and treated musts. Moreover, this technique has proven to be very efficient in the reduction of aerobic mesophilic microorganisms as well as in the reduction of residual polyphenol oxidase activities, being lower than those obtained with SO2 addition (60 and 160 mg/L). Based on the results, the most convenient conditions were 100 bar and 10% CO2, for 10 min treatment.

Enhanced Physiological and Biochemical Performance of Mung Bean and Maize under Saline and Heavy Metal Stress through Application of Endophytic Fungal Strain SL3 and Exogenous IAA

Modern irrigation practices and industrial pollution can contribute to the simultaneous occurrence of salinity and heavy metal contamination in large areas of the world, resulting in significant negative effects on crop productivity and sustainability. This study aimed to investigate the growth-promoting potentials of an important endophytic fungal strain SL3 and to compare its potential with exogenous IAA (indole-3-acetic acid) in the context of salt and heavy metal stress. The strain was assessed for plant growth-promoting traits such as the production of indole-3-acetic acid, gibberellins (GA), and siderophore. We selected two important crops, mung bean and maize, and examined various physiological and biochemical characteristics under 300 mM NaCl and 2.5 mM Pb stress conditions, with and without the application of IAA and SL3. This study's results demonstrated that both IAA and SL3 positively impacted the growth and development of plants under normal and stressed conditions. In NaCl and Pb-induced stress conditions, the growth of mung bean and maize plants was significantly reduced. However, the application of IAA and SL3 helped to alleviate stress, leading to a significant increase in shoot/root length and weight compared to IAA and SL3 non-treated plants. The results revealed that photosynthetic pigments, accumulation of catalase (CAT), phenolic contents, polyphenol oxidase, and flavanols are higher in the IAA and SL3-treated plants than in the non-inoculated plants. This study's findings revealed that applying the SL3 fungal strain positively influenced various physiological and biochemical processes in tested plant species under normal and stress conditions of NaCl and Pb. These findings also suggested that SL3 could be a potential replacement for widely used IAA to promote plant growth by improving photosynthetic efficiency, reducing oxidative stress, and enhancing metabolic activities in plants, including mung and maize. Moreover, this study highlights that SL3 has synergistic effects with IAA in enhancing resilience to salt and heavy stress and offers a promising avenue for future agricultural applications in salt and heavy metal-affected regions.

Non-Thermal Supercritical Carbon Dioxide Processing Retains the Quality Parameters and Improves the Kinetic Stability of an Araticum Beverage Enriched with Inulin-Type Dietary Fibers

Fruit-based beverages have been considered excellent food vehicles for delivering prebiotics. However, the conventional thermal processes currently used to microbiologically and enzymatically stabilize these products may cause significant losses in their sensory, physicochemical, nutritional, and bioactive characteristics. Thus, in this study, we evaluate the effect of different levels of pressure (8, 15, and 21 MPa) and temperature (35 and 55 °C) on the characteristics of an inulin-enriched araticum beverage processed with non-thermal supercritical carbon dioxide (SC-CO₂) technology. The temperature showed a significant effect on total soluble solids, pH, particle size distribution, and kinetic stability. In contrast, pressure affected only the particle size distribution. The interaction between pressure and temperature influenced the total soluble solids, pH, and particle size distribution. Color parameters, ζ-potential, and glucose and fructose contents were not modified after all SC-CO₂ treatments. Moreover, the SC-CO₂ treatments preserved the inulin molecular structure, thus maintaining its prebiotic functionality. Overall, the SC-CO₂ treatment did not alter the sensory, nutritional, and functional quality of the beverage, while improving its physical stability during storage. Therefore, non-thermal SC-CO₂ treatment can be an alternative to current conventional processes for stabilizing inulin-enriched fruit-based beverages.

Production of small peptides and low molecular weight amino acids by subcritical water hydrolysis from fish meal: effect of pressurization agent and comparison with enzymatic hydrolysis

The hydrolysis of the water-soluble protein (WSP) fraction from tuna fish meal was evaluated by subcritical water (subW) by using N₂ and CO₂ as different pressurization agents in the temperature range from 140 to 180 °C. For both gases, the amino group release increased by increasing working temperature while the Lowry response decreased due to production of smaller-size peptides and free amino acids. The free amino acid content was higher with CO₂ than with N₂. At 180 °C, 344 ± 5 and 275 ± 3 mg of free amino acids per g of WSP were released, respectively; although, in both systems the smallest molecular weight amino acids, glycine and alanine, were preferentially released. The free amino acids content obtained by enzymatic hydrolysis with commercial proteases Alcalase and Novozym was much lower with the highest hydrolysis yield determined for histidine. These results have been supported by size exclusion chromatography analysis.

The effect of supercritical carbon dioxide on the physiochemistry, endogenous enzymes, and nutritional composition of fruit and vegetables and its prospects for industrial application: a overview

Consumers have an increasing demand for fruit and vegetables with high nutritional value worldwide. However, most fruit and vegetables are vulnerable to quality loss and spoilage during processing, transportation, and storage. Among the recently introduced emerging technologies, supercritical carbon dioxide (SCCO2) has been extensively utilized to treat and maintain fruit and vegetables mainly due to its nontoxicity, safety, and environmentally friendly. SCCO2 technology generates low processing costs and mild processing conditions (temperature and pressure) that allow for the application of CO2 at a supercritical state. This review aimed to summarize the current knowledge on the influence of SCCO2 technology on the quality attributes of fruit and vegetable products, such as physicochemical properties (pH, color, cloud, particle size distribution, texture), sensory quality, and nutritional composition (ascorbic acid, phenolic compounds, anthocyanins, carotenoids, and betalains). In addition, the effects and mechanisms of the SCCO2 technique on endogenous enzyme inactivation (polyphenol oxidase, peroxidase, and pectin methylesterase) were also elucidated. Finally, the prospects of the SCCO2 technique for industrial application was discussed from the economic and regulatory aspect.

Enzymatic browning in apple products and its inhibition treatments: A comprehensive review

Apple (Malus domestica) is widely consumed by consumers from various regions. It contains a high number of phenolic compounds (majorly hydroxybenzoic acids, hydroxycinnamic acids, flavanols, flavonols, dihydrochalcones, and anthocyanins) and antioxidant activity, which are beneficial for human health. The trends on healthy and fresh food have driven the food industry to produce minimally processed apple, such as fresh-cut, puree, juice, and so on without degrading the quality of products. Enzymatic browning is one of the problems found in minimally processed apple as it causes the undesirable dark color as well as the degradation of phenolics and antioxidant activity, which then reduces the health benefits of apple. Proper inhibition is needed to maintain the quality of minimally processed apple with minimal changes in sensory properties. This review summarizes the inhibition of enzymatic browning of apple products based on recent studies using the conventional and nonconventional processing, as well as using synthetic and natural antibrowning agents. Nonconventional processing and the use of natural antibrowning agents can be used as promising treatments to prevent enzymatic browning in minimally processed apple products. Combination of 2-3 treatments can improve the effective inhibition of enzymatic browning. Further studies, such on as other potential natural antibrowning agents and their mechanisms of action, should be conducted.

How to comprehensively improve juice quality: a review of the impacts of sterilization technology on the overall quality of fruit and vegetable juices in 2010-2021, an updated overview and current issues

Fruit and vegetable juices (FVJ) are rich in nutrients, so they easily breed bacteria, which cause microbial pollution and rapid deterioration of their quality and safety. Sterilization is an important operation in FVJ processing. However, regardless of whether thermal sterilization or non-thermal sterilization is used, the effect and its impact on the overall quality of FVJ are strongly dependent on the processing parameters, microbial species, and FVJ matrix. Therefore, for different types of FVJ, an understanding of the impacts that different sterilization technologies have on the overall quality of the juice is important in designing and optimizing technical parameters to produce value-added products. This article provides an overview of the application of thermal and non-thermal technique in the field of FVJ processing over the past 10 years. The operating principle and effects of various technologies on the inactivation of microorganisms and enzymes, nutritional and functional characteristics, physicochemical properties, and sensory quality of a wide range of FVJ are comprehensively discussed. The application of different combinations of hurdle technology in the field of FVJ sterilization processing are also discussed in detail. Additionally, the advantages, limitations, and current application prospects of different sterilization technologies are summarized.

Understanding the combined effect and inhibition mechanism of 4-hydroxycinnamic acid and ferulic acid as tyrosinase inhibitors

The development of tyrosinase inhibitors to prevent the enzymatic browning have become a research hotspot in food industry. 4-Hydroxycinnamic acid (CA) and ferulic acid (FA) are both the derivates of cinnamic acids, which are widely coexisted in plants seeds and leaves. CA combined with FA (inhibition rate of 90.44%) were found to effectively inhibit tyrosinase activity than employing CA and FA alone (inhibition rate of 12.15% and 22.17%, respectively). CA-FA-tyrosinase complex resulted in fluorescence quenching. The first-order kinetics and Weibull models well described the inactivation of tyrosinase at 2-4 mM and 6-10 mM of CA and FA, respectively. Additionally, UV-vis spectrum indicated that several characteristic groups such as hydroxyl group in CA competed with the nucleophilic attack of intramolecular cyclization, leading to the decrease of characteristic peak. Molecular docking further studied that CA and FA interacted with the activity cavity of tyrosinase by amino acids residues Ser282, His263, and Val283.

Optimization of biotechnological processes in the production of apple juice

When obtaining apple juice, the issue of optimizing biotechnological processes is acute. The use of enzyme preparations of different specifics of the action allows you to choose the optimal parameters of the technological process and select the drug taking into account the purpose ofuse. The influence of enzyme preparations: Trinoline 4000, Trinolin DF, Fructocyme P6-L, Lafaze on the yield of juice and biologically active substances in the processing of fruit raw materials was studied. An enzyme preparation that maximizes the yield of apple juice has been isolated. Their effect on the extraction of biologically active substances has been determined.

Impact of pulsed magnetic field treatment on enzymatic inactivation and quality of cloudy apple juice

The effects of PMF (5-7 T, 5-30 pulses) on enzyme activity, pH, titratable acidity, soluble solids, color, ascorbic acid, total phenols and antioxidant activity (DPPH radical scavenging activity) of cloudy apple juice were evaluated. PMF inhibited activities of polyphenoloxidase (PPO), peroxidase (POD) and pectinmethylesterase (PME), but PPO was more sensitive to PMF than POD and PME. At the intensity of 6 T with 15 pulses, PPO and POD both exhibited the lowest residual activity (53.22 and 92.96%), while PME showed the lowest residual activity (83.01%) at 7 T with 30 pulses. No significant effect on soluble solids was found under all processing parameters, whereas significant decreases of ascorbic acid were observed at the intensity of 7 T with 5-30 pulses. PMF did not change pH, titratable acidity, color, total phenols and DPPH radical scavenging activity severely. These results suggest PMF can be a potential technology for enzymatic inactivation in apple juice with high retention of quality.

Contribution of Special Structural Features to High Thermal Stability of a Cold-Active Transglutaminase

A cold-active transglutaminase (TGase, EC 2.3.2.13) that catalyzes the reaction of protein glutamine + protein lysine ↔ protein with γ-glutamyl-ε-lysine cross-link + NH₃ at low temperatures was reported previously. This study verified the thermal stability of the TGase from 0-80 °C. Fluorescence and CD spectra studies confirmed tertiary structural damage at 40 °C, α-helix reduction at 60 °C, and refolding during cooling to 20 °C. The TGase sequence was obtained by transcriptomics and used to build its structure. Its catalytic triad was Cys333-His403-Asp426 and its catalytic process was inferred from the model. Molecular dynamics simulation illustrated that its cold activity resulted from its flexible active site, while high thermostability was conferred by an overall rigid structure, a large amount of stable Val and Lys, and strong electrostatic interactions at the N- and C- terminals. This study fills gaps in the correlation of conformational changes with stability and activity of TGase.

Inactivation and structural changes of polyphenol oxidase in quince (Cydonia oblonga Miller) juice subjected to ultrasonic treatment

BACKGROUND

Polyphenol oxidase (PPO) is considered a problem in the food industry because it starts browning reactions during fruit and vegetable processing. Ultrasonic treatment is a technology used to inactivate the enzyme; however, the mechanism behind PPO inactivation is still unclear. For this reason, the inactivation, aggregation, and structural changes in PPO from quince juice subjected to ultrasonic treatments were investigated. Different intensities and times of ultrasonic treatment were used. Changes in the activity, aggregation, conformation, and structure of PPO were investigated through different structural analyses.

RESULTS

Compared to untreated juice, the PPO activity in treated juice was reduced to 35% at a high ultrasonic intensity of 400 W for 20 min. The structure of PPO determined from particle size distribution (PSD) analysis showed that ultrasound treatment caused initial dissociation and subsequent aggregation leading to structural modification. The spectra of circular dichroism (CD) analysis of ultrasonic treated PPO protein showed a significant loss of α-helix, and reorganization of secondary structure. Fluorescence analysis showed a significant increase in fluorescence intensity of PPO after ultrasound treatment with evident blue shift, revealing disruption in the tertiary structure.

CONCLUSION

In summary, ultrasonic treatment triggered protein aggregation, distortion of tertiary structure, and loss of α-helix conformation of secondary structure causing inactivation of the PPO enzyme. Hence, ultrasound processing at high intensity and duration could cause the inactivation of the PPO enzyme by inducing aggregation and structural modifications. © 2019 Society of Chemical Industry.

Enzymatic, Phyto-, and Physicochemical Evaluation of Apple Juice under High-Pressure Carbon Dioxide and Thermal Processing

In this study, the changes in enzyme activities, total polyphenols, phenolic profile, and physicochemical properties from thermally (25–75 °C) and high-pressure carbon dioxide (HP-CO₂) (25–65 °C/20 MPa)-treated apple juice were investigated. The HP-CO₂ exhibited complete inactivation of polyphenol oxidase (PPO) at 65 °C, whereas PPO was still active at 75 °C under thermal processing (TP). Similarly, the relative activity of peroxidase (POD) significantly decreased by 71% at 65 °C under HP-CO₂ processing, whereas TP was less effective. HP-CO₂ and TP treatments at 65 °C reduced the browning degree (BD) value to 0.47 and 0.89, respectively. Thus, HP-CO₂ inhibits the browning reactions caused by PPO and POD enzymes at each operating temperature. The concentration of epicatechin and catechin increased significantly with increasing temperature above 45 °C in TP-treated juices. HP-CO₂ treatment increased the same phenolic compounds at 35 °C and 9 MPa, whereas high-temperature and -pressure conditions caused insignificant changes in concentration of epicatechin and catechin. Changes in others phenolic compounds were insignificant under TP and HP-CO₂ treatment. Overall, HP-CO₂ is a promising technology to get high-quality juices with lower enzyme activity.

Effect of cold plasma on polyphenol oxidase inactivation in cloudy apple juice and on the quality parameters of the juice during storage

Direct cold plasma treatment has been investigated as an alternative non-thermal technology as a means of maintaining and improving quality of fresh cloudy apple juice. Process variables studied included type of plasma discharge, input voltage and treatment time on polyphenol oxidase (PPO) inactivation. Spark discharge plasma at 10.5 kV for 5 min was the best treatment, with near total inactivation of PPO achieved, although good PPO inactivation was also recorded using shorter treatment times. Residual activity (RA) of PPO was 16 and 27.6% after 5 and 4 min of treatment respectively. This PPO inactivation was maintained throughout the storage trials, but decreased with samples treated for a shorter time. Plasma treatment improved key quality parameters of Golden delicious cloudy apple juice, with retention of critical quality parameters during extended storage trials. Color was the most noticeable change, which was enhanced with retention of a greener color. An increase of 69 and 64% was obtained in the total phenolic content after 4 and 5 min of treatment, respectively. Therefore, cold plasma was demonstrated to be a good alternative to traditional heat treatments for enhanced quality retention of fresh cloudy apple juice and over its storage.

Structural changes of a protein extract from apple with polyphenoloxidase activity obtained by cationic reversed micellar extraction induced by high-pressure carbon dioxide and thermosonication

Polyphenoloxidase from apple was extracted and further concentrated by cationic reversed micellar extraction. Previous to reversed micellar extraction a crude protein extract was obtained using AG2-X8 as adsorbent of phenolic compounds and the detergent Triton X-100. Forward and backward extraction conditions were optimized by using dodecyl trimethyl ammonium bromide as surfactant in the organic phase. Optimization was carried out to obtain the highest value of PPO activity recovery and the purification fold at the different experimental conditions. Under the optimum extraction conditions, PPO activity recovery was 99% and purification fold reached a value of 17, showing that reversed micellar extraction was a good technique as a first step to concentrate on a targeted enzyme. After removing some impurities by centrifuge ultrafiltration, the protein extract with PPO activity was treated by pressurized carbon dioxide and thermosonication achieving residual PPO activity values of 16 ± 3 and 9 ± 1%, respectively. Quenching experiments by iodide performed in the non-treated extract and in the treated extracts revealed conformational changes of this protein fraction reflected in the greater exposure of the fluorophore to the quencher.

Effects of elevated carbon dioxide on environmental microbes and its mechanisms: A review

Before the industrial revolution, the atmospheric CO₂ concentration was 180-330 ppm; however, fossil-fuel combustion and forest destruction have led to increased atmospheric CO₂ concentration. CO₂ capture and storage is regarded as a promising strategy to prevent global warming and ocean acidification and to alleviate elevated atmospheric CO₂ concentration, but the leakage of CO₂ from storage system can lead to rapid acidification of the surrounding circumstance, which might cause negative influence on environmental microbes. The effects of elevated CO₂ on microbes have been reported extensively, but the review regarding CO₂ affecting different environmental microorganisms has never been done previously. Also, the mechanisms of CO₂ affecting environmental microorganisms are usually contributed to the change of pH values, while the direct influences of CO₂ on microorganisms were often neglected. This paper aimed to provide a systematic review of elevated CO₂ affecting environmental microbes and its mechanisms. Firstly, the influences of elevated CO₂ and potential leakage of CO₂ from storage sites on community structures and diversity of different surrounding environmental microbes were assessed and compared. Secondly, the adverse impacts of CO₂ on microbial growth, cell morphology and membranes, bacterial spores, and microbial metabolism were introduced. Then, based on biochemical principles and knowledge of microbiology and molecular biology, the fundamental mechanisms of the influences of carbon dioxide on environmental microbes were discussed from the aspects of enzyme activity, electron generation and transfer, and key gene and protein expressions. Finally, key questions relevant to the environmental effect of CO₂ that need to be answered in the future were addressed.

Enzymatic, physicochemical, nutritional and phytochemical profile changes of apple (Golden Delicious L.) juice under supercritical carbon dioxide and long-term cold storage

The impact of supercritical carbon dioxide (SCCD) (10-60 MPa/45 °C/30 min) and subsequent 10 weeks storage at 4 °C on polyphenol oxidase (PPO), peroxidase (POD) activities, phenolic profile, vitamin C, sugars, physicochemical properties of cloudy apple juices was investigated. No significant changes in sugars and total polyphenols were observed, whereas significant degradation (≈28%) of vitamin C and individual polyphenols (≈18%) was noted after SCCD treatment. After 4 weeks storage only 34% of vitamin C was retained and no vitamin C was detected after this time. Ten weeks of storage caused hydrolysis of sucrose in 15%, whereas degradation of individual polyphenols ranged from 43 to 50% depending on the pressure applied. The highest pressure was applied the highest retention of polyphenols was observed. The lightness of juice significantly increased by 15% after SCCD and decreased during storage. Moreover, the synergistic effect of both enzymes with chlorogenic acid and catechol was found.