Effect of PEF and heat pasteurization on the physical–chemical characteristics of blended orange and carrot juice

Effect of pulsed electric field (PEF) on NaCl diffusion in beef and consequence on meat quality

The impact of various field strength (2, 3, 4 kV/cm) and treatment time (60s and 90s) combinations on NaCl content and diffusion coefficient of beef were evaluated in the current study. Weight change, water content, water holding capacity, and texture of beef after brining were also explored. The results demonstrated pulsed electric field (PEF) pre-treatment significantly increased NaCl uptake when the brining time was 150 min (P < 0.05). The maximum NaCl content increased by 19.50% and the diffusion coefficient increased by 58.50%. Relatively mild PEF (60s) could improve beef qualities, but longer treatment time (90s) was detrimental to these qualities. Meanwhile, more complete myofibrillar structure and lower lipid oxidation extent were observed in the samples treated by PEF, contributing to the higher a* values. In conclusion, short processing time (60s) and high field strength (4 kV/cm) treatment is a potential strategy for meat brining acceleration and quality improvement in practical industrial production.

Sonication and thermal treatment of pineapple juice: Comparative assessment of the physicochemical properties, antioxidant activities and microbial inactivation

Sonication is a novel processing method that is perceived as a substitute for heat treatment to ensure the safety of juice while reducing the loss of nutrients during processing. The impacts of sonication and thermal processing on pineapple juice, including physicochemical properties, antioxidant activities, and microbial inactivation, were studied. Pineapple juice was sonicated at 100 W and 140 W (for 5, 10 and 15 min) and heat-treated at 70 °C, 80 °C and 90 °C (for 1 min). Results indicated minor alterations in physicochemical characteristics after sonication and thermal processing, while sonication treatment showed better retention of the color, clarity, and browning index of pineapple juice. Moreover, sonication significantly increased the bioactive compounds (total carotenoids, ascorbic acid, phenolics, and flavonoids) and boosted the antioxidant activity of pineapple juice compared to the heat-processed juice. Although sonication reduced the microbial load significantly with the increasing exposure time, it could not thoroughly inactivate microorganisms like thermal treatment. Therefore, optimal sonication processing conditions are required to be determined. This study will help the food processors utilize sonication treatment in pineapple juice processing plants to inactivate microorganisms thoroughly while also boosting the nutritional value.

Advances in pulsed electric stimuli as a physical method for treating liquid foods

There is a need for alternative technologies that can deliver safe and nutritious foods at lower costs as compared to conventional processes. Pulsed electric field (PEF) technology has been utilised for a plethora of different applications in the life and physical sciences, such as gene/drug delivery in medicine and extraction of bioactive compounds in food science and technology. PEF technology for treating liquid foods involves engineering principles to develop the equipment, and quantitative biochemistry and microbiology techniques to validate the process. There are numerous challenges to address for its application in liquid foods such as the 5-log pathogen reduction target in food safety, maintaining the food quality, and scale up of this physical approach for industrial integration. Here, we present the engineering principles associated with pulsed electric fields, related inactivation models of microorganisms, electroporation and electropermeabilization theory, to increase the quality and safety of liquid foods; including water, milk, beer, wine, fruit juices, cider, and liquid eggs. Ultimately, we discuss the outlook of the field and emphasise research gaps.

Evaluation of different extracts leaves and seed husks of some Terminalia spp. had cultivated in Egypt on orange juice.. [DOI: 10.21203/rs.3.rs-2417062/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Terminalia trees had-cultivated in Egypt for getting wood and windbreak. seed husks and leaves (young and old) of T. bellirica and T. arjuna had light acrid, arguable and tasteless on characteristic taste, respectively. Meanwhile, T. bellirica seed husks are more capable of total sugars percentage compared to T. arjuna seed husks (11.2 and 10.3%) respectively. Generally, ethanol solvent enhanced aqueous extract on all treatments.T. bellirica seed husks had the highest significant increased total phenol and total tannin content. In this concern, young leaves of T. bellirica enhanced significantly to total flavonid content. T. bellirica and T. arjuna had a high significant increased on antioxidant content (38.550.3 and 36.450.58 mg) respectively. Meanwhile, mature leaves of terminalia sp. had a significant increased in K, Mg, Ca, Mn, Fe and Zn content. On the other side additive both extracts of different terminalia sp. portions save pH, browning and turbidity of juice with no significant during 7 days storage in room temperature while juice still without significant change until 1days under 4Cº. Terminalia extract significantly enhanced the sensory of juice. In general, treated with terminalia extract had a significant increase in phenol, tannin, flavonoid and DPPH of juice content.

Evaluation of Active LDPE Films for Packaging of Fresh Orange Juice

Microbial development, enzymatic action, and chemical reactions influence the quality of untreated natural orange juice, compromising its organoleptic characteristics and causing nutritional value loss. Active low-density polyethylene (LDPE) films containing green tea extract (GTE) were previously prepared by a blown film extrusion process. Small bags were prepared from the produced films, which were then filled with fresh orange juice and stored at 4 °C. Ascorbic acid (AA) content, sugar content, browning index, color parameters, pH, total acidity (TA) and microbial stability were evaluated after 3, 7, and 14 days of storage. The packaging containing GTE maintained the microbial load of fresh juice beneath the limit of microbial shelf-life (6 log CFU/mL) for the bacterial growth, with a more prominent effect for LDPE with 3%GTE. Regarding yeasts and molds, only the CO_LDPE_3GTE package maintained the microbial load of fresh juice below the limit for up to 14 days. At 14 days, the lowest levels of AA degradation (32.60 mg/100 mL of juice) and development of brown pigments (browning index = 0.139) were observed for the packages containing 3% of GTE, which had a pH of 3.87 and sugar content of 11.4 g/100 mL of juice at this time. Therefore, active LDPE films containing 3% of GTE increase the shelf-life of fresh juice and can be a promising option for storage of this food product while increasing sustainability.

Non-Conventional Induction Heat Treatment: Effect of Design and Electrical Parameters on Apple Juice Safety and Quality

The proposed non-conventional induction heating, which combines an MSCP and VDC structure, was proved to have excellent thermal effect. Different from other electric field sterilization, this electrotechnology operates with no electrodes, and it is a continuous-flow process with short-duration (about 20 s). In current study, the parameters related to temperature rise were investigated, including applied voltage, frequency, the diameter of the secondary coil and heating tube, as well as their length, etc. It was demonstrated that a smaller diameter of the heating tube, parallel connection sample coils, and higher frequency were beneficial for the inactivation of microorganisms. At 500 Hz, the optimal condition is 800 V, d₁ = 2 mm, and L₁ = 10 cm. Notably, the system could inactivate all microorganisms and maintained the physicochemical properties of apple juice at 40 kHz. It suggests that this structural design has the potential for industrial applications and the proposed induction heating can realize the rapid sterilization of liquid food without applying electrodes.

Applications of Innovative Non-Thermal Pulsed Electric Field Technology in Developing Safer and Healthier Fruit Juices

The deactivation of degrading and pectinolytic enzymes is crucial in the fruit juice industry. In commercial fruit juice production, a variety of approaches are applied to inactivate degradative enzymes. One of the most extensively utilized traditional procedures for improving the general acceptability of juice is thermal heat treatment. The utilization of a non-thermal pulsed electric field (PEF) as a promising technology for retaining the fresh-like qualities of juice by efficiently inactivating enzymes and bacteria will be discussed in this review. Induced structural alteration provides for energy savings, reduced raw material waste, and the development of new products. PEF alters the α-helix conformation and changes the active site of enzymes. Furthermore, PEF-treated juices restore enzymatic activity during storage due to either partial enzyme inactivation or the presence of PEF-resistant isozymes. The increase in activity sites caused by structural changes causes the enzymes to be hyperactivated. PEF pretreatments or their combination with other nonthermal techniques improve enzyme activation. For endogenous enzyme inactivation, a clean-label hurdle technology based on PEF and mild temperature could be utilized instead of harsh heat treatments. Furthermore, by substituting or combining conventional pasteurization with PEF technology for improved preservation of both fruit and vegetable juices, PEF technology has enormous economic potential. PEF treatment has advantages not only in terms of product quality but also in terms of manufacturing. Extending the shelf life simplifies production planning and broadens the product range significantly. Supermarkets can be served from the warehouse by increasing storage stability. As storage stability improves, set-up and cleaning durations decrease, and flexibility increases, with only minor product adjustments required throughout the manufacturing process.

Effect of Hurdle Approaches Using Conventional and Moderate Thermal Processing Technologies for Microbial Inactivation in Fruit and Vegetable Products

Thermal processing of packaged fruit and vegetable products is targeted at eliminating microbial contaminants (related to spoilage or pathogenicity) and extending shelf life using microbial inactivation or/and by reducing enzymatic activity in the food. The conventional process of thermal processing involves sterilization (canning and retorting) and pasteurization. The parameters used to design the thermal processing regime depend on the time (minutes) required to eliminate a known population of bacteria in a given food matrix under specified conditions. However, due to the effect of thermal exposure on the sensitive nutrients such as vitamins or bioactive compounds present in fruits and vegetables, alternative technologies and their combinations are required to minimize nutrient loss. The novel moderate thermal regimes aim to eliminate bacterial contaminants while retaining nutritional quality. This review focuses on the “thermal” processing regimes for fruit and vegetable products, including conventional sterilization and pasteurization as well as mild to moderate thermal techniques such as pressure-assisted thermal sterilization (PATS), microwave-assisted thermal sterilization (MATS) and pulsed electric field (PEF) in combination with thermal treatment as a hurdle approach or a combined regime.

Two-Step PEF Processing for Enhancing the Polyphenol Concentration and Decontaminating a Red Grape Juice

This study’s aim is to evaluate Pulsed Electric Fields (PEF) technology as an alternative method for the processing of red grape juice. For this purpose, two PEF treatments were applied: first to grapes for polyphenol enrichment of the juice, and subsequently for microbial decontamination of the obtained juice. Juice obtained from PEF-treated grapes (5 kV/cm, 63.4 kJ/kg) had the polyphenol content 1.5-fold higher and colour intensity two times higher of control juices by spectrophotometric measurement (p ≤ 0.05). A subsequent decontamination treatment by PEF (17.5 kV/cm and 173.6 kJ/kg) achieved inactivation of the present microbiota (yeasts, moulds, and vegetative mesophilic bacteria) below detection level (<30 CFU/mL). Furthermore, PEF-treated juices were microbiologically stable up to 45 days, even at abusive refrigeration storage temperatures (10 °C). PEF juice quality and sensory characteristics were similar to a fresh juice; they were neither affected by the PEF decontamination treatment, nor by storage time and temperature. Results obtained in this study demonstrate the considerable potential of PEF for the production of a polyphenol-enriched and microbially stabilized red grape juice as a unique and sustainable alternative for the juice industry, while avoiding enzymatic and heat treatments.

Effect of High Hydrostatic Pressure on the Extractability and Bioaccessibility of Carotenoids and Their Esters from Papaya (Carica papaya L.) and Its Impact on Tissue Microstructure

High hydrostatic pressure (HHP) is a non-thermal technology widely used in the industry to extend food shelf-life and it has been proven to enhance the extractability of secondary metabolites, such as carotenoids, in plant foods. In this study, fresh-cut papaya pulp of varieties (Sweet Mary, Alicia and Eksotika) from the Canary Islands (Spain) were submitted to the HHP process (pressure: 100, 350 and 600 MPa; time: come-up time (CUT) and 5 min) to evaluate, for the first time, individual carotenoid and carotenoid ester extractability and to assess their bioaccessibility using an in vitro simulated gastrointestinal digestion assay, following the standardized INFOGEST^® methodology. In addition, changes in papaya pulp microstructure after HHP treatments and during the different phases of the in vitro digestion were evaluated with optical light microscopy. HPLC-DAD (LC-MS/MS (APCI+)) analyses revealed that HHP treatments increased the carotenoid content, obtaining the highest extractability in pulp of the Sweet Mary papaya variety treated at 350 MPa during 5 min (4469 ± 124 μg/100 g fresh weight) which was an increase of 269% in respect to the HHP-untreated control sample. The highest carotenoid extraction value within each papaya variety among all HHP treatments was observed for (all-E)-lycopene, in a range of 98–1302 μg/100 g fresh weight (23–344%). Light micrographs of HHP-treated pulps showed many microstructural changes associated to carotenoid release related to the observed increase in their content. Carotenoids and carotenoid esters of papaya pulp submitted to in vitro digestion showed great stability; however, their bioaccessibility was very low due to the low content of fatty acids in papaya pulp necessary for the micellarization process. Further studies will be required to improve papaya carotenoid and carotenoid ester bioaccessibility.

Impact of high-intensity thermosonication treatment on spinach juice: Bioactive compounds, rheological, microbial, and enzymatic activities

To study the impacts of thermosonication (TS), the spinach juice treated with TS (200 W, 400 W, and 600 W, 30 kHz, at 60 ± 1 °C for 20 mint) were investigated for bioactive compounds, antioxidant activities, color properties, particle size, rheological behavior, suspension stability, enzymatic and microbial loads. As a result, TS processing significantly improved the bioactive compounds (total flavonols, total flavonoids, total phenolic, carotenoids, chlorophyll, and anthocyanins), antioxidant activities (DPPH and FRAP assay) in spinach juice. Also, TS treatments had higher b*,L*, hue angle (h⁰), and chroma (C) values, while minimuma* value as compared to untreated and pasteurized samples. TS processing significantly reduced the particle size, improved the suspension stability and rheological properties (shear stress, apparent viscosity, and shear rate) of spinach juice as compared to the untreated and pasteurized sample. TS plays a synergistic part in microbial reduction and gained maximum microbial safety. Moreover, TS treatments inactivated the polyphenol oxidase and peroxidase from 0.97 and 0.034 Abs min^-1 (untreated) to 0.31 and 0.018 Abs min^-1, respectively. The spinach juice sample treated at a high intensity (600 W, 30 kHz, at 60 ± 1 °C for 20 mint, TS3) exhibited complete inactivation of microbial loads (<1 log CFU/ml), the highest reduction in enzymatic activities, better suspension stability, color properties, and highest bioactive compounds. Collectively, the verdicts proposed that TS processing could be a worthwhile option to pasteurize the spinach juice to enhance the overall quality.

Thermosonication effect on bioactive compounds, enzymes activity, particle size, microbial load, and sensory properties of almond (Prunus dulcis) milk

The object of this research was to appraise the physicochemical characteristics of almond milk and consumer acceptability after the thermosonication (TS) processing. The almond milk was subjected to TS processing (frequency: 40 kHz; power: 600 W; Temperature: 30, 45, and 60 °C; Time: 10, 20, 30, and 40 min) and pasteurization (for 60 s at 90 °C). After treatments, all samples were analyzed for bioactive compounds, antioxidant activities, microbial, enzymatic, and sensory attributes. The results showed a non-significant difference in total soluble solids and pH while TS processing at 45 and 60 °C significantly increased the cloudiness, viscosity, browning index, and color properties. TS processing increased the bioavailability of total phenolic, flavonols, flavonoids, condensed tannin contents, and antioxidant activity as compared to untreated and pasteurized samples. TS processing also significantly reduced the particle size distribution through acoustic cavitation. Microbial inactivation with TS at 60 °C resulted in ≥ 5 log reduction oftotal plate count and ≥ 4 log reduction ofyeast & moldwas achieved. The highest inhibition of lipoxygenase (LOX) and peroxidase (POD) were observed at 60 °C for 30 min. Moreover, the best sensorial properties were observed after TS processing at 60 °C. Thus; TS processing can increase the almond milk quality and safety as a viable substitute for thermal processing.

Viability, Sublethal Injury, and Release of Cellular Components From Alicyclobacillus acidoterrestris Spores and Cells After the Application of Physical Treatments, Natural Extracts, or Their Components

Alicyclobacillus acidoterrestris is a spoiling microorganism regarded as one of the most important causes of spoilage of fruit juices and acidic products. In this paper, four strains of A. acidoterrestris (type strain-DSM 3922; two wild strains isolated from soil-C8 and C24; wild strain isolated from a spoiled pear juice CB1) were treated through natural extracts/active compounds from essential oils (EOs), and physical treatments were used to assess their susceptibility and the presence of sublethal injury. The characterization of damage was also performed. The results suggest that it is possible to control A. acidoterrestris through alternative approaches, although the effect relied upon the age of spores. In addition to the mere antimicrobial effect, some treatments could cause a sublethal injury on spores. Lemon extract was the most effective treatment for both the antimicrobial effect and the sublethal injury, as evidenced by the release of proteins, and calcium dipicolinate [dipicolinic acid (DPA)] by fresh spores and only DPA (with an exception for C8) by old spores. A sublethal injury with protein release was also found for physical treatments [US (ultrasound) or heating]. For the first time, this paper reports on the existence of a sublethal injury for A. acidoterrestris, and this evidence could also be a challenge, because injured microorganisms could restore their metabolism, or an opportunity to design new preserving treatments.

Application of Thermosonication in Red Pitaya Juice Processing: Impacts on Native Microbiota and Quality Properties during Storage

The effects of thermosonication (TS) on microbial safety and quality of red pitaya juice during storage were assessed in this study. Freshly prepared red pitaya juices were thermosonicated at 475 W and 56 °C for 20 min. Upon TS processing, native microbiota including aerobic bacteria, yeasts, and molds reduced to less than 10 CFU/mL. Their growth during storage were slow and equal to thermal-processed (83 °C, 1.5 min) samples. During storage at 4 °C for 28 days, soluble solid content, pH, activities of polyphenol oxidase and peroxidase, and browning degree remained unchanged. A visible color decay was observed in TS-processed samples at day 10, mainly resulting from decomposition of betacyanins and the growth of residual native microbiota. Compared to thermal-treated juices, better color retention was obtained by TS treatment. Therefore, TS is a promising alternative technology of thermal methods of juice processing, with equal shelf life and better quality retention effects.

Effect of thermosonication on quality attributes of hog plum (Spondias mombin L.) juice

The use of thermosonication (TS) technique to preserve the qualities of fruit juice as an alternative to conventional pasteurization has attracted research interest in recent times. In the present study, freshly prepared hog plum juice (control), and the juice samples subjected to pasteurization (90 °C for 60 s) and thermosonication (40 kHz, 400 W at 40, 50 and 60 °C each for 5, 10, 20 and 30 min) were each analyzed for physicochemical, bioactive, microbial and sensory properties. After treatment, no significant changes in pH, total soluble solids and titratable acidity were observed. Notably, TS at 40 and 50 °C significantly (p < 0.05) improved color parameters, cloudiness and browning index. Furthermore, thermosonication increased ascorbic acid (11.40-18.55%), total phenolic content (17.98-18.35%), carotenoids (2.19-4.30%), flavonoids (10-16%) and antioxidant activity (32.52-48.5%) relative to the control. Both treatments significantly reduced the microbial count to non-detectable level after processing, while sensory attributes slightly improved. However, TS treatment at 60 °C decreased most of the quality parameters. Results showed that TS can improve quality, safety and economic potential of hog plum juice as a feasible alternative to pasteurization.

Effects of kiwi's pectin methylesterase inhibitor, nanomilling and pasteurization on orange juice quality

Endogenous pectin methylesterase (PME) is the enzyme responsible for phase separation and cloud loss in orange juice (OJ) manufacturing. The effect of kiwi's PME inhibitor (PMEI), nanomilling, and pasteurization on OJ quality was evaluated. The microbial quality, PME activity, OJ separation, pH, ascorbic acid content and the sensory characteristics of the juice were followed during 5 weeks storage (4°C). PMEI as freeze-dried kiwi powder (0.3%, w/w) succeeded in inhibiting 89.3% of the OJ PME without affecting the microbial and the sensory quality. Nanomilling of OJ pulp, to prepare nano-particles OJ (NPOJ), reduced the initial microbial load by 1.65 and 1.83 log for psychrotrophs and yeasts and molds, respectively; significantly (p < .05) inactivated 40.9% of the residual PME activity and the juice separation was significantly reduced by 48.3% (after 14 days of storage). Nanomilling exhibited no effect on OJ pH, but slight (p < .05) decrease in ascorbic acid content was noted. The combination of PMEI with NPOJ resulted in improved OJ stability with reduced separation to 36.4% of that of control. Such combination also allowed to use a lower pasteurization temperature at lower exposure time (60°C/5 min) needed to obtain new NPOJ with comparable high quality as fresh OJ and which has a shelf life of 3 weeks (4°C).

Effect of dielectric barrier discharge plasma, ultra-sonication, and thermal processing on the rheological and functional properties of sugarcane juice

The present work was designed to study the impact of dielectric barrier discharge (DBD) plasma, ultrasound (US), and thermal treatment on the functional, rheological, and microbial analysis of sugarcane juice. The results showed that plasma and US treatment did not significantly affect the pH and color of the juice. Total soluble solids (°Brix) value increased from 16.30 ± 0.10 for untreated to 20.50 ± 0.15 during plasma treatment at 45 V for 2 min and 16.65 ± 0.27 during US treatment (40 kHz, power 240 W, and time 40 min). The maximum increase of 25% in total phenolic contents (TPC) and 21% in total flavonoid contents (TFC) was observed in a plasma-treated sample at 40 and 45 V (for 2 min) respectively, whereas 18% in TPC and 16% TFC was observed in the US-treated sample (40 kHz, power 240 W, and time 30 min) as compared to control sample. Plasma treatment increased the antioxidant activities (Ferric reducing antioxidant power (FRAP) assay and 2,2-Diphenyl-1-picrylhydrazyl (DPPH) activity) toward maximum at 40 V and only 6% of vitamin C was degraded than others. Similarly, plasma treatment significantly reduced particle size, which further led to decreased significantly (P < 0.05) the apparent viscosity of sugarcane juice with a rise in shear rate and drove to a speedy breakdown on initial shearing. A significant reduction was observed in the microbial load among all treatments as compared to the control. Significant reductions of 3.6 and 0.50 log CFU/mL were observed in the total aerobic mesophilic and yeast and mold counts after DBD plasma treatment at 45 V for 2 min, respectively. Thus, we can conclude that novel technology like plasma treatment can be effectively used at an industrial scale for the preservation and processing of sugarcane juice. PRACTICAL APPLICATION: Nowadays, novel processing techniques are employed to improve the nutritional quality and stability of juices. The consequences of the present research showed that DBD plasma treatment could improve the TPC, TFC, antioxidant activities, vitamin C, and rheological properties while reducing the activity of the microbial load better than the US and thermal treatment. The verdicts described that novel processing methods can enhance the quality of sugarcane juice at an industrial scale.

Effect of Stand-Alone and Combined Ultraviolet and Ultrasound Treatments on Physicochemical and Microbial Characteristics of Pomegranate Juice

The objective of this study was to determine the combined usage possibilities of ultraviolet (UV) and ultrasonic (US) processes in the pasteurization of pomegranate juice. For this purpose, UV, US, and combined UV+US pasteurization of pomegranate juice were optimized using experimental designs, such as the Central Composite Design (CCD) and Factorial Design (FD), and compared with the conventional pasteurization process. Total phenolic content (TPC), color a*, water-soluble dry matter (°Brix), turbidity, anthocyanin, DPPH, HPLC TPC, and yeast and mold count were used as quality parameters during all of the processes. The results showed that the application of 50 °C, 3.5 L/min flow rate and 5.1 mW/cm2 UV dose, and 10 min US (200 Watt) together reduced the microbial population below the detection limits. The integration of UV+US processes into the pasteurization process could limit microbial activity at lower temperatures and times than the conventional pasteurization process, thus preserving the existing bioactive compounds.

Pulsed Electric Field-Assisted Ethanolic Extraction of Date Palm Fruits: Bioactive Compounds, Antioxidant Activity and Physicochemical Properties

The current study was aimed to observe the influence of pulsed electric field (PEF) on the extraction of bioactive components; antioxidant activity and physicochemical properties of date palm fruit extract (DPFE) as compared to the extract untreated by PEF. The fruit was treated with PEF (frequency: 10 Hz, time: 100 µs, pulses number: 30, electric field strength (EFS): 1, 2, and 3 kV/cm. The results show that PEF has a positive impact on the total content of carotenoids, anthocyanins, flavonoids, and phenolics by increasing the EFS. DPFE treated with PEF exhibit a strong antioxidant activity as compared to untreated extract, while electrical conductivity, pH values, and titratable acidity were not affected by PEF. The results indicate a notable increase in the volatile components in DPFE treated with PEF at 3 kV/cm. Thus, PEF treatment can assist the ethanolic extraction of DPFE to improve the bioactivity and antioxidative activity. These findings suggest that PEF can be a more suitable technique to enhance solvent extraction on a commercial basis.

Effect of batch and continuous thermosonication on the microbial and physicochemical quality of pumpkin juice

The study investigated the use of batch and continuous thermosonication for pasteurization of pumpkin (Cucurbita moschata) juice emphasizing on its microbial, physicochemical and sensorial quality parameters. Batch thermosonication (40, 50, 60 °C, 37 kHz, 150 W) of pumpkin juice was compared with the ultrasonication (23 °C) and conventional heat treatments (40, 50, 60 °C). For batch thermosonication, maximum inactivation of Escherichia coli K-12 was 6.62 ± 0.00 log cfu/mL, meanwhile, it was 3.64 ± 0.19 log cfu/mL for heat treatment. In addition, only 0.37 ± 0.21 log cfu/mL inactivation in E. coli K-12 was obtained by ultrasonication. The designed continuous thermosonication system (0.029 L/min, 60 °C) reduced E. coli K-12 by 6.23 ± 0.34 cfu/mL log after cycle 3 (34.15 min of processing). Color properties (L*, a*, b*, ∆E), pH, total titratable acidity, total soluble solids content, turbidity and non-enzymatic browning index were determined for batch and continuously thermosonicated, ultrasonicated and heat-treated pumpkin juices. Total color change of continuously thermosonicated samples were higher than the batch thermosonicated (60 °C) ones but, lower than the conventional heat treated (60 °C) samples. Sensory panel showed general acceptance scores of fresh, batch (60 °C) and continuously thermosonicated pumpkin juice samples have no significant (P < 0.05) difference. Continuous treatment results supported by the batch ones revealed that thermosonication could be effectively used for pasteurization of pumpkin juice producing a safe product with minimum changes in physicochemical and sensorial properties.

Impact of adding goldenberry (Physalis peruviana L.) on some quality characteristics and bio-functional properties of pasteurized carrot (Daucus carota L.) nectar

Goldenberry juice was added in ratios of 0% (T1), 20% (T2), 30% (T3), 40% (T4) and 50% (T5) to carrot juice. Then the blends were mixed with sucrose solution (1:1), and pasteurized at 98 °C for 2 min. The produced carrot-goldenberry nectars were analyzed for physicochemical, sensory and microbial characteristics, in comparison to the carrot nectar, during 28 days of a cold storage at 4 °C. Results showed that the addition of goldenberry juice significantly increased the levels of acidity, total soluble solids, ascorbic acid and total phenolic compounds along with antioxidant activity for all nectars when compared to the control carrot nectar (T1). In contrast, the levels of turbidity and β-carotene were significantly decreased by the addition of goldenberry. For color parameters, both L* and a* values were significantly decreased, while b* values were significantly increased by the addition of goldenberry. Goldenberry improved the organoleptic properties of the carrot nectar, and reduced deterioration in these properties during storage. Moreover, the results of microbial analysis indicated that all nectars were microbiologically safe (counts of total aerobic count and yeast and mold were less than 1 log10 CFU/mL). The carrot-goldenberry nectar (T3) had the highest overall acceptability during storage time. The obtained results valorize exploiting of goldenberry juice in processed fruit products like jams, juices and syrups.

Pasteurization of mixed mandarin and Hallabong tangor juice using pulsed electric field processing combined with heat

Effects of pulsed electric filed (PEF) processing combined with heating (H-PEF processing) on the inactivation of microorganisms and the physicochemical properties of mixed mandarin and Hallabong tangor (MH) juice were studied. Using a pilot-scale PEF system, MH juice, pre-heated at 55 °C, was PEF-treated at 19 kV/cm of electric field and 170 kJ/L of specific energy and the juice, pre-heated at 70 °C, was PEF-treated at 16 kV/cm and 100 kJ/L or 12 kV/cm and 150 kJ/L. H-PEF processing at 70 °C-16 kV/cm-100 kJ/L reduced the aerobe, yeast/mold, and coliform counts of MH juice by 3.9, 4.3, and 0.8 log CFU/mL, respectively, without affecting the ascorbic acid concentration and antioxidant capacity of juice. H-PEF processing changed juice color and browning degree (p < 0.05), but not total soluble solid content or pH. By controlling initial juice temperature and electric field strength, H-PEF processing can be an effective pasteurization method for mixed juice with minimal changes in quality.

Current and future prospects for the use of pulsed electric field in the meat industry

Pulsed electric field (PEF) is a novel non-thermal technology that has recently attracted the attention of meat scientists and technologists due to its ability to modify membrane structure and enhance mass transfer. Several studies have confirmed the potential of pulsed electric field for improving meat tenderness in both pre-rigor and post-rigor muscles during aging. However, there is a high degree of variability between studies and the underlying mechanisms are not clearly understood. While some studies have suggested physical disruption as the main cause of PEF induced tenderness, enzymatic nature of the tenderization seems to be the most plausible mechanism. Several studies have suggested the potential of PEF to mediate the tenderization process due to its membrane altering properties causing early release of calcium ions and early activation of the calpain proteases. However, experimental research is yet to confirm this postulation. Recent studies have also reported increased post-mortem proteolysis in PEF treated muscles during aging. PEF has also been reported to accelerate curing, enhance drying and reduce the numbers of both pathogens and spoilage organisms in meat, although that demands intense processing conditions. While tenderization, meat safety and accelerated curing appears to be the areas where PEF could provide attractive options in meat processing, further research is required before the application of PEF becomes a commercial reality in the meat industry. It needs to deal with carcasses which vary biochemically and in composition (muscle, fat, and bones). This review critically evaluates the published reports on the topic with the aim of reaching a clear understanding of the possible applications of PEF in the meat sector in addition to providing some insight on critical issues that need to be addressed for the technology to be a practical option for the meat industry.