Thermal Pasteurization Research Articles

Impact of UV-C irradiation on the quality, safety, and cytotoxicity of cranberry-flavored water using a novel continuous flow UV system

The influence of short wavelength UV-C irradiation at 254 nm on microbial inactivation, anthocyanins stability, ascorbic acid, and cytotoxicity of formulated cranberry flavored water was studied. Escherichia coli ATCC 25922 and Salmonella enterica serovar Typhimurium ATCC 13311 were inactivated by more than 5 log10 at UV-C fluence of 21 mJ cm−2. At UV-C fluence of 40 mJ cm−2 the content of ascorbic acid was 82% of that in the untreated beverage. The concentrations of the anthocyanins (Cy3Ar, Cy3Ga, Pe3Ar, and Pe3Ga) were not significantly affected at the same treatment level. Cytotoxicity evaluation of the irradiated beverage on normal colon (CCD-18Co), colon cancer (HCT-116), and healthy mice liver (AML-12) cells showed that UV-C irradiation had no cytotoxic effects on all three cell lines. This research study suggests that UV-C treatment of formulated cranberry flavored water can achieve high levels of microbial inactivation without significantly decreasing the concentration of anthocyanins, ascorbic acid content or generating cytotoxic effects. These results suggest that UV-C irradiation can be an alternative to thermal pasteurization in producing high quality beverages.

Comparison between thermal pasteurization and high pressure processing of bovine skim milk in relation to denaturation and immunogenicity of native milk proteins

Abstract High pressure processing (HPP), conducted at 400, 500 or 600 MPa for 15 min at 30 °C, of raw skim milk was studied in comparison to high-temperature short-time (HTST) pasteurization (72 °C for 15 s), considering protein denaturation and immunogenicity. HTST pasteurization least impacted denaturation of native proteins leading to mostly unchanged milk immunogenicity. HPP resulted in denaturation of whey proteins, mostly β-lactoglobulin (BLG) and immunoglobulin G (IgG), and disturbed structure of the casein micelle. HPP at 600 MPa caused protein aggregation, involving mainly BLG and κ-casein, through thiol disulphide interactions. α-Lactalbumin (ALA) was least denatured. The balance between expression of T helper (Th)1 and Th2 type cytokines, which is believed to regulate adverse immune response, was initially shifted toward Th1 with increasing high pressure, then the immunogenic capacity of milk proteins diminished at 600 MPa. This could be related to exposure of T cell-specific linear epitopes followed by unfolding of protein structure firstly and masking of them by protein aggregation subsequently with increasing high pressure. Industrial relevance HPP of raw milk has been well studied as an alternative process for conventional thermal pasteurization, based on inactivation of microorganisms and extension of shelf life. However, HPP can denature native milk proteins leading to altered immunogenicity. Three recommended HPP conditions and a commercial HPP method were assessed in comparison to HTST pasteurization considering impact on denaturation of milk proteins and milk immunogenicity. Scientific findings of the current study would guide the industry to identify HPP conditions that not only achieve the required level of microbial inactivation and shelf life, but also to establish desired levels of native properties of milk and milk immunogenicity.

Effect of low thermal pasteurization in combination with carvacrol on color, antioxidant capacity, phenolic and vitamin C contents of fruit juices.

Mild thermal treatment in combination with natural antimicrobials has been described as an alternative to conventional pasteurization to ensure fruit juices safety. However, to the best of our knowledge, no study has been undertaken to evaluate what could be its effect on their color and nutritional value. This study therefore aimed at assessing how a low thermal pasteurization in combination with carvacrol could affect these parameters, with orange, pineapple, and watermelon juices as selected fruit juices. The experimental design used had levels ranging from 50 to 90°C, 0 to 60 μl/L, and 0 to 40 min for temperature, concentration of carvacrol supplemented, and treatment length, respectively. The only supplementation of fruit juices with carvacrol did not affect their color. In comparison with high thermal pasteurization (>70°C), a combined treatment at mild temperatures (50–70°C) better preserved their color, antioxidant capacity (AOC), and vitamin C content, and increased their total phenolic content (TPC). Globally, carvacrol supplementation had a positive impact on the TPC of thermally treated juices and increased the AOC of treated watermelon juice, which was the lowest of the three fruit juices. Mild heat treatment in combination with natural antimicrobials like carvacrol is therefore an alternative to limit the negative effects of conventional pasteurization on fruit juices quality.

The effects of UV-C treatment on the quality of orange, carrot and celery juice blend

However, current methods that are used in the processing of juice products, such as thermal treatments, has been reported significantly reduces nutritional quality. UV-C treatment is an alternative method that could extend the shelf life as well as maintain the quality of juice. In this study, the quality attributes of the juice blend upon exposure to ultraviolet light and thermal treatment were studied. Freshly squeezed orange, carrot and celery juice blend was exposed to ultraviolet light (for 15, 30, and 60 minutes) and thermal pasteurization (at 90°C, for 30 s and 60 s). Microbial analysis, physicochemical properties, antioxidant activity as well as other quality parameters were carried out on all samples. The results showed no significant difference in physicochemical properties among all samples studied. Nevertheless, a significant increase was observed in polyphenol content, antioxidant capacity, and flavonoid content in samples treated with UV-C compared to control and thermal treated. Moreover, juice blend exposed to UV-C treatment (30 and 60 minutes) showed increase in extractability of carotenoids. UV-C treated samples also exhibited reduction in microbial load and prolonged shelf life. The results obtained support the use of UV-C as an alternative to thermal treatment in improving the quality of juice blend.

The simultaneous effect of electromagnetic and ultrasound treatments on Escherichia coli count in red grape juice

Introduction: The thermal pasteurization is a common method for maintaining fruit juice and increasing shelf life, but the thermal processing changes the flavor and color of the products. The aim of this study was to investigate the effect of a new method of combining heat and ultrasound on the number of the Escherichia coli present in grape juice.Methods: In this study, the effects of the microwave power, temperature, ultrasound power and ultrasonic exposure time were evaluated on E. coli count of red grape juice. In order to determine the microbial inactivation by microwave and ultrasound, E. coli at a concentration of 6×106 per mL was inoculated to red grape juice.Results: The effects of microwave power, grape juice temperature, ultrasound power and ultrasonic exposure time on the reduction of E. coli were significant (P < 0.05). The model showed that in reducing E. coli the importance of the final temperature of the juice was higher than the microwave power. In addition, the ultrasonic power was more effective in E. coli reduction as compared to the microwave power.Conclusion: Both sample temperature and ultrasonic duration were important independent variables and effective factors on E. coli reduction.

High isostatic pressure and thermal processing of açaí fruit (Euterpe oleracea Martius): Effect on pulp color and inactivation of peroxidase and polyphenol oxidase

The present study evaluated the effect of high isostatic pressure (HIP) on the activity of peroxidase (POD) and polyphenol oxidase (PPO) from açaí. Açaí pulp was submitted to several combinations of pressure (400, 500, 600MPa), temperature (25 and 65°C) for 5 and 15min. The combined effect of HIP technology and high temperatures (690MPa by 2 and 5min at 80°C) was also investigated and compared to the conventional thermal treatment (85°C/1min). POD and PPO enzyme activity and instrumental color were examined after processing and after 24h of refrigerated storage. Results showed stability of POD for all pressures at 25°C, which proved to be heat-resistant and baro-resistant at 65°C. For PPO, the inactivation at 65°C was 71.7% for 600MPa after 15min. In general, the increase in temperature from 25°C to 65°C reduced the PPO relative activity with no changes in color. Although the thermal treatment and the HIP (690MPa) along with high temperature (80°C) reduced the PPO relative activity, and relevant darkening was observed in the processed samples. Thus, it can be concluded that POD is more baro-resistant than PPO in açaí pulp subjected to the same HIP processing conditions and processing at 600MPa/65°C for 5min may be an effective alternative for thermal pasteurization treatments.

Ultra-High Temperature Effect on Bioactive Compounds and Sensory Attributes of Orange Juice Compared with Traditional Processing

Abstract Orange juices are an important source of bioactive compounds. Because of its unique combination of sensory attributes and nutritional value, orange juice is the world’s most popular fruit juice. Orange (Citrus sinensis) juice of Greek Navel variety was used in this study. The impact of Conventional Thermal Pasteurisation (94 °C/30') (CTP) and alternative Ultra-High Temperature (UHT) (130 °C/2') processing on bioactive compounds and antioxidant capacity changes of fresh Navel orange juice was investigated. Sensory attributes of processed juices were evaluated. Results showed that using technologies CTP and UHT orange juice Navel significantly changed vitamin C concentration in comparison with fresh orange juice. The highest concentration of antioxidants (vitamin C, total phenols, hesperidin and carotenoids) was observed in orange juice Navel produced by UHT technology. Sensory results indicated that characteristics of the orange juice obtained using UHT technology were more liked than the CTP heat treated juice. UHT technology emerges as an advantageous alternative process to preserve bioactive compounds in orange juice.

Pulsed electric fields as an alternative to thermal processing for preservation of nutritive and physicochemical properties of beverages: A review

AbstractFruit juices and other beverages constitute an important source of bioactive compounds, but thermal processing may reduce their contents thus decreasing natural nutritive value of foods. This has been recently led to the use of non‐thermal technologies, especially pulsed electric fields (PEF) as an interesting alternative to thermal pasteurization of beverages. Reported results show that PEF is a useful for pasteurization of fruit juices that can minimize changes in physicochemical and nutritional properties with retention of higher amounts of health‐related phytochemicals. This study presents an overview of the effect of PEF on the physicochemical (e.g., Brix, pH, viscosity, acidity, color, aroma, and flavor, etc.) and nutritional (e.g., fatty acids and free amino acids, bioactive compounds, antioxidant capacity, etc.) properties of beverages.Practical applicationsPulsed electric fields is suitable technological option for pasteurization, able to preserve valued bioactive compounds in beverages. Over the last decade, PEF has attracted a significant interest from various food industries and found numerous applications. However, chemical profile of food matrices has great influence on PEF, hence success of the treatment has to be evaluated and reported for each particular food. Accordingly, this review made systematic overview of the effects of PEF processing on the physicochemistry and nutrition with focus on beverages manufactured from various raw materials. Provided data can be applied for steering future uses of the PEF in processing, as well as directions of the future research with this useful technology.

Evaluation of the Gauss-Eyring model to predict thermal inactivation of micro-organisms at short holding times

Application of mild (non)-thermal processing technologies have received considerable interest as alternative to thermal pasteurisation, because of its shorter holding time and lower temperature aiming for an improved product quality. To understand and develop these alternative technologies, like pulsed electric fields, a proper comparison between the conventional thermal and alternative process is necessary. Up to recent, no suitable models were available to predict the inactivation of micro-organisms by a thermal process at a chosen short holding time, due to non-linearity. The recently developed Gauss-Eyring model with two variables temperature and time has the properties to be a suitable model to apply for short holding times, and was tested for this purpose.Therefore, this study aims to validate if the Gauss-Eyring model can be used to describe non-linear isothermal (a fixed temperature with varying holding time) and isotime (a fixed holding time with varying temperature) thermal inactivation data, and if it is a suitable model to predict the thermal inactivation as a function of temperature for short holding times.Inactivation data of Escherichia coli, Listeria monocytogenes, Lactobacillus plantarum, Salmonella Senftenberg and Saccharomyces cerevisiae in orange juice were collected via isothermal and isotime inactivation kinetics. Survival of the tested micro-organisms was modelled with the Gauss-Eyring model, which contains three parameters σ, Tr and Z. The transition of ‘no inactivation’ to ‘inactivation’ (i.e. the ‘shoulder’ in inactivation curves) can be characterised as the temperature-time (T,t) combination where T=Tr−Z·log10(t), with Tr as the reference temperature defined for 1s treatment, Z as the temperature needed for a 10-fold increase of decrease of the holding time t, and σ as the temperature width of the distribution.The Gauss-Eyring model fitted well to the experimental data, and revealed different sensitivity for the tested micro-organisms. Based on the parameter estimations, survival curves for the desired short holding times were predicted.

Effect of ultrasound on microbiological load and antioxidant properties of blackberry juice

The objective of this study was to evaluate the effect of ultrasound (60 and 80% amplitude, 15 and 25 min) of blackberry juice on physicochemical (pH and total soluble solids), microbiological analysis (total plate count and Enterobacteria), and in vitro intestinal bioaccessibility of polyphenols and antioxidant activity (ABTS, DPPH). Ultrasound treatment caused a decrease of microbial count of blackberry juice and remained its physicochemical properties without change. The blackberry juice had a high antioxidant activity, however, after of the in vitro digestion process only 28% of total polyphenols were considered as intestinally bioaccessible, with the contribution of 30 to 60% of antioxidant activity in the bioaccesible fraction. The treatment at 80% amplitude for 15 min was the better treatment due it had an increase of bioaccessibility of polyphenols and antioxidant activity measured by ABTS. Our results showed that ultrasound treatment can preserve the blackberry juice without impairing to its antioxidant characteristics. Practical applications Blackberries are mostly consumed fresh but are also commercialized as individually quick frozen packs, bulk, frozen, seedless or seeded puree, freeze-dried, juice, or concentrate. During fruit juices processing, thermal treatment and other conditions such as oxidation, light exposure, sugar addition, changes in pH, and temperature readily reduce the content of antioxidant compounds and its nutritional properties. Ultrasound is a non-thermal processing technology with potential to replace the traditional thermal pasteurization, achieve microbial safety in fruit juices and remained its antioxidant properties of the blackberry juice.

Energy-efficient Legionella control that mimics nature and an open-source computational model to aid system design

Although there is no direct connection, the incidence of Legionnaire’s disease has increased concurrently with increased usage of energy efficient domestic hot water (DHW) systems, which serve as ideal growth environments for Legionella pneumophila, the bacteria responsible for Legionnaire’s disease. The Duck Foot Heat Exchange Model (DFHXM) was developed to aid design of energy efficient thermal pasteurization systems with Legionella control specifically in mind. The model simulates a system design imitating the countercurrent heat exchange in the feet of ducks, an evolutionary adaption reducing environmental heat losses in cold climates. Such systems use a heat exchanger to preheat fluids prior to pasteurization and cool the same fluid after pasteurization. Thus, the design requires minimal addition of heat to achieve pasteurization temperatures and to cover environmental heat losses. This article describes the underlying principles and use of the freely available Microsoft Excel model, as well as compares results from the DFHXM to measurements of an experimental pilot system. Simulation outputs agreed well with experimental results for transient and steady-state temperatures, the largest discrepancy in steady-state temperatures being 4.6%. Lastly, we discuss the flexibility of the DFHXM to simulate a wide variety of designs with special emphasis on Legionella control and solar-thermal water disinfection.

Stability of astaxanthin-loaded nanostructured lipid carriers in beverage systems.

Nanostructured lipid carriers (NLCs) offer many potential benefits for incorporating lipophilic molecules into clear to opaque food systems. This study examined the stability of astaxanthin-loaded NLCs (Ax-NLCs) in model (solutions with 0 or 12% sucrose; pH 3, 7), semi-actual (whey) and actual (non-alcoholic beer) beverages during 30-60 days storage at 6 or 20 °C. Ax-NLCs (Z-average size: 94 nm), containing α-tocopherol and EDTA as antioxidants, were stabilised with Tween 80 and lecithin, and mixed with the aforementioned beverages at the volume ratio of 3:97. The presence of sucrose, improved the physical stability of Ax-NLCs in acidic model beverage. No astaxanthin loss and particle size growth were observed for Ax-NLCs-added whey. Carbonation and/or thermal pasteurisation of NLCs-added beer led to a major increase in its particles size and astaxanthin loss. Stability of Ax-NLCs in non-pasteurised CO2 -free beer improved at low storage temperature. The organoleptic quality of NLCs-added beers was still acceptable. These results indicate that NLCs containing hydrophobic nutraceuticals have potential to be used for functional beverages/foods development. © 2017 Society of Chemical Industry.

Kinetics of Protein Degradation and Physical Changes in Thermally Processed Atlantic Salmon (Salmo salar)

Protein denaturation is the main reason for physicochemical changes in muscle foods during thermal processing. The purpose of this study was to understand the kinetics of quality degradation and protein denaturation of Atlantic salmon (Salmo salar) during thermal pasteurization. Findings indicate that cook loss, area shrinkage, and protein denaturation parameters (both dielectric loss and differential scanning calorimetry (DSC) studies) were best fitted to a first-order reaction. In addition, color parameters followed zero-order kinetics. Fourier transform infrared spectroscopy (FTIR) results showed that increasing heating time and temperature reduced the α-helix peak, indicating protein denaturation. At the same time, the β-sheet peak intensity increased, which is related to protein aggregation. Correlation loading plots from FTIR spectra showed that protein denaturation was dominant below 75 °C. Above this transition temperature, protein denaturation occurred rapidly and protein aggregation became more obvious. The dielectric properties in cooked salmon at different times and temperature increased with increasing heating time and temperature, while penetration depth decreased significantly (P < 0.05). The kinetics of protein denaturation from DSC showed that the activation energy of 300.6 kJ/mol and k 0 was 1.1 × 1042 min−1. Our findings on kinetic data from protein denaturation and physical changes may be used to improve the processing schedule in the production of safe, high-quality pasteurized salmon.

Green Pea and Garlic Puree Model Food Development for Thermal Pasteurization Process Quality Evaluation.

Development and selection of model foods is a critical part of microwave thermal process development, simulation validation, and optimization. Previously developed model foods for pasteurization process evaluation utilized Maillard reaction products as the time-temperature integrators, which resulted in similar temperature sensitivity among the models. The aim of this research was to develop additional model foods based on different time-temperature integrators, determine their dielectric properties and color change kinetics, and validate the optimal model food in hot water and microwave-assisted pasteurization processes. Color, quantified using a* value, was selected as the time-temperature indicator for green pea and garlic puree model foods. Results showed 915 MHz microwaves had a greater penetration depth into the green pea model food than the garlic. a* value reaction rates for the green pea model were approximately 4 times slower than in the garlic model food; slower reaction rates were preferred for the application of model food in this study, that is quality evaluation for a target process of 90 °C for 10 min at the cold spot. Pasteurization validation used the green pea model food and results showed that there were quantifiable differences between the color of the unheated control, hot water pasteurization, and microwave-assisted thermal pasteurization system. Both model foods developed in this research could be utilized for quality assessment and optimization of various thermal pasteurization processes.

Non Thermal Pasteurization for Orange Juice Using Pulsed Electric Field

Pasteurization is an act or a process to minimize or eliminate all forms of life, particularly microorganisms in food products. Its aim is to reduce or eliminate the number of viable pathogens, which are likely to cause diseases. Pasteurization can be in the form of thermal and non-thermal methods. Thermal pasteurization typically uses high heat and temperature to reduce or eliminate microorganisms. Although this method has been practiced and proven effective, the process is associated with many side effects. Due to this problem, new approaches using a non-thermal pasteurization to generate pulsed electric field (PEF) is proposed. In this paper, non-thermal sterilization using Cascaded H-Bridge Multilevel Inverter (CHMI) pulse power generator was evaluated in order to produce pulsed electric field in inactivating of microorganisms such as Saccharomyces cerevisiae and Escherichia coli in orange juice. The experimental set-up was conducted where an orange juice was placed inside the treatment chamber. The electrodes between the treatment chamber were applied with pulsed electric field up to 15 kV/cm by using the CHMI. The hardware development was implemented using MOSFET 2K3748 power devices and the gate signal generator was controlled by using dSPACE DS 1104. The experimental results show that, an output voltage of 1.2 kVp−p was effective to inactivate Escherichia coli and Saccharomyces cerevisiae. Thus, power consumption was decreased and energy was saved. The pulsed width of 1000 μs with repetitive rate of 50 Hz was generated from the hardware implementation. The results proved that the specifications of the experimental set-up meet the requirements for liquid food sterilization, particularly to inactivate Escherichia coli and Saccharomyces cerevisiae microorganisms in orange juice by using streaking plate techniques.

Application of non-enzymatic browning of fructose for heating pattern determination in microwave assisted thermal pasteurization system

Various model foods and chemical markers have been used for the heating pattern determination in microwave processing at sterilization temperatures (110–130 °C). These chemical marker systems have slow reaction rates and are not useful at pasteurization temperatures (70–90 °C). In this study, non-enzymatic browning of fructose under alkaline conditions is investigated for its suitability to be used in the heating pattern determination for microwave assisted thermal pasteurization. Kinetics of browning of fructose in the mashed potato model food were studied. The model food samples were heated in a water bath at 60 °C, 70 °C, 80 °C and 90 °C for different time intervals and the browning kinetics were studied by spectrophotometric measurements at 420 nm. Reaction rate kinetics were fit to a linear first order kinetic model. Application of this model food to determine the heating pattern in the microwave assisted thermal pasteurization system was demonstrated. Dielectric properties of the mashed potato were measured to determine its suitability as a model food. Sucrose and salt were used as effective additives for the adjustment of the dielectric constants and loss factor respectively of the mashed potato. This system offers advantages of being cost-effective, opaque, homogeneous and easy to handle and thus provides an excellent system to locate the hot and cold spots of the food products.

Thermal pasteurization process evaluation using mashed potato model food with Maillard reaction products

Model foods with Maillard reaction product formation have been utilized to evaluate thermal sterilization processes, but these models are not optimal for pasteurization. Model foods for pasteurization applications have been developed, but studies on temperature sensitivity and validation are limited. The goal of this research was to assess the temperature sensitivity of chemical marker and color formation in mashed potato model foods and conduct validation testing using a microwave-assisted pasteurization system (MAPS) and conventional, hot water methods. Reaction kinetics were determined for chemical marker M-2 (4-hydroxy-5-methyl-3(2H)-furanone) and color formation (L* and a* values). Results showed that the thermal resistance constants (z-values) were 20.6–24.0 °C for M-2, 20.8–28.8 °C for L* value, and 10.3–25.6 °C for a* value. Correlation analysis between M-2, L*, and a* values and thermal lethality and cook value showed that model foods were most relevant for pasteurization process quality evaluation. Thermal treatment equivalent at the cold spot was approximately 11 min at 90 °C for all pasteurization processes. Model foods pasteurized in MAPS had less color change than those from hot water processes, implying the less severe MAPS process yielded better quality. Model foods and image analysis techniques used in this study could be helpful quality evaluation tools for pasteurization processes.

Non-thermal pasteurization of apples in syrup with dense phase carbon dioxide

The study investigated dense phase carbon dioxide (DPCD) applicability to a solid-liquid product consisted of apples in syrup as an alternative to the conventional thermal pasteurization. The effect of pressure (8, 10, and 12 MPa) and temperature (35, 45, and 55 °C) at 15 min was investigated to determine the inactivation of the natural microbiota (mesophilic microorganisms, total coliforms, yeasts and molds) and polyphenol oxidase enzyme. The optimal process conditions (12 MPa, 55 °C, 15 min) were determined. A storage study at 25 °C for 60 days was also performed to monitor the microbial, enzymatic and quality (pH, color, ascorbic acid content and total acidity) stability of the product.DPCD induced inactivation to undetectable levels of mesophilic microorganisms, total coliforms, yeasts and molds. At the same conditions, polyphenol oxidase was totally inactivated while pH, color, and total acidity were slightly affected. The shelf life study of DPCD treated products revealed their microbial, enzymatic and quality stability.

Food Quality Evaluation using Model Foods: a Comparison Study between Microwave-Assisted and Conventional Thermal Pasteurization Processes

Thermal process optimization has focused on traditional sterilization, with limited research on pasteurization or microwave-assisted thermal processing. Model foods have been developed as quality evaluation tools for thermal pasteurization processes, but there are no comprehensive studies demonstrating how these model foods could be used to evaluate and compare the resulting food quality after different pasteurization processes. The aim of this study was to develop a methodology using image and quantitative analyses for quality evaluation of pre-packaged food pasteurized using a microwave-assisted pasteurization system (MAPS) and traditional hot water method. Four pasteurization processes (MAPS and hot water method at 90 and 95 °C) were designed to have an equivalent accumulated thermal lethality at the cold spot of at least 90 °C for 10 min to control nonproteolytic Clostridium botulinum spores. Color-based time-temperature indicators in mashed potato and green pea model foods were quantified using image analysis. Results showed that median color values were useful in assessing overall color change, and interquartile range was an indicator of burnt areas. MAPS 95 °C was the best process because it had the smallest hot spot cook values and the least color change, while the 90 °C hot water process was the worst. Model foods and image analysis techniques were useful pasteurization process quality evaluation tools and made it possible to visualize the potential food quality change volumetrically, throughout a food package. In the future, these tools could be combined with computer simulations to optimize the quality of pilot-scale and industrial MAPS or conventional pasteurization processes.

Nutritional, microbial and physicochemical changes in pear juice under ultrasound and commercial pasteurization during storage

In this study, the microbial and nutritional aspects of pear juice with conventional or ultrasound (US) treatment during storage at 4 °C were studied. The conventional pasteurization was 95 °C for 5 min while US-pasteurizations (frequency 30 kHz, amplitude 70%) were 25, 45, and 65 °C for 10 min, under a probe sonicator (750 W). Control, US25 and US45 had shelf lives of 9, 12, and 15 days respectively. Ascorbic acid, total phenols, total anti oxidant capacity, and cloud value decreased in all treatments while pH, acidity, and sugars remained stable. Both treatments (P95 and US65) remained viable after 21 days of storage, however, loss of bioactive compounds in P95 (16.39%) was significantly higher than that of US65 (7.44%), indicating US-pasteurization a promising pear juice processing technology at low temperature, retaining bioactive compounds, meeting safety standards, and increasing shelf life. Practical applications Complete microbial and enzymatic deactivation is achieved at commercial thermal pasteurization techniques, but these elevated temperatures cause losses in nutritional and sensory attributes of the end product. While microbial and enzymatic deactivation in pear juice was achieved at lower temperature using thermosonication in the present study. The low temperature pasteurizations exhibited higher retention and availability of bioactive compounds than the traditional high temperature pasteurizations over the studied shelf life period. The findings of the study would pave way for the commercial processing of pear juice with improved quality and shelf life.