High Pressure Thermal Processing Research Articles

Leveraging artificial intelligence for simplified adiabatic compression heating prediction: Comparing the use of artificial neural networks with conventional numerical approach

This study presents a comprehensive evaluation of artificial neural networks (ANNs) for predicting adiabatic compression heating in high-pressure processing (HPP) and high-pressure thermal processing (HPTP). The ANNs were thoroughly compared with experimental data, as well as data predicted by a previously developed approach. This previous approach used numerical methods to extract relevant material properties from experimental data, which was then used for compression heating predictions by solving an ordinary differential equation. The new work showcases the efficacy of ANNs in accurately predicting compression heating effects. The results indicate that ANNs offer a robust, flexible, and efficient approach for modelling adiabatic heating, with significant implications for the design and optimisation of HPTP treatments. The study underscores the transformative potential of AI in advancing food preservation technologies.

Recent Progress in the Synergistic Bactericidal Effect of High Pressure and Temperature Processing in Fruits and Vegetables and Related Kinetics.

Traditional thermal processing is a widely used method to ensure food safety. However, thermal processing leads to a significant decline in food quality, especially in the case of fruits and vegetables. To overcome this drawback, researchers are extensively exploring alternative non-thermal High-Pressure Processing (HPP) technology to ensure microbial safety and retaining the sensory and nutritional quality of food. However, HPP is unable to inactivate the spores of some pathogenic bacteria; thus, HPP in conjunction with moderate- and low-temperature is employed for inactivating the spores of harmful microorganisms. Scope and approach: In this paper, the inactivation effect of high-pressure and high-pressure thermal processing (HPTP) on harmful microorganisms in different food systems, along with the bactericidal kinetics model followed by HPP in certain food samples, have been reviewed. In addition, the effects of different factors such as microorganism species and growth stage, process parameters and pressurization mode, and food composition on microbial inactivation under the combined high-pressure and moderate/low-temperature treatment were discussed. The establishment of a reliable bactericidal kinetic model and accurate prediction of microbial inactivation will be helpful for industrial design, development, and optimization of safe HPP and HPTP treatment conditions.

Multitarget preservation technologies for chemical-free sustainable meat processing.

Due to the growing consumer demand for safe and naturally processed meats, the meat industry is seeking novel methods to produce safe-to-consume meat products without affecting their sensory appeal. The green technologies can maintain the sensory and nutritive characteristics and ensure the microbial safety of processed meats and, therefore, can help to reduce the use of chemical preservatives in meat products. The use of chemical additives, especially nitrites in processed meat products, has become controversial because they may form carcinogenic N-nitrosamines, a few of which are suspected as cancer precursors. Thus, the objective of reducing or eliminating nitrite is of great interest to meat researchers and industries. This review, for the first time, discusses the influence of processing technologies such as microwave, irradiation, high-pressure thermal processing (HPTP) and multitarget preservation technology on the quality characteristics of processed meats, with a focus on their sensory quality. These emerging technologies can help in the alleviation of ingoing nitrite or formed nitrosamine contents in meat products. The multitarget preservation technology is an innovative way to enhance the shelf life of meat products through the combined use of different technologies/natural additives. The challenges and opportunities associated with the use of these technologies for processing meat are also reviewed.

Immunological components and antioxidant activity in human milk processed by different high pressure-thermal treatments at low initial temperature and flash holding times

The effect of high pressure thermal (HPT) processing on the immunoglobulin (IgM, IgA and IgG), and cytokine content (IL-6, IL-8, IL-10, and TNF-α), and antioxidant activity of human milk was analyzed after the application of different treatments between 200, and 800 MPa at low initial temperatures (between −15, and 50 °C) and for 1 s (flash treatments). Low pressures intensities did not induce changes in Igs while at 800 MPa, all combinations reduced the control levels. IL-6 and IL-10 were not affected by any of the treatments applied while IL-8 and TNF-α were reduced at treatments which combined temperatures at 50 °C. In general antioxidant activity was not affected at the processing conditions chosen. The flash HPT treatment applied at 600 MPa and at 0 °C could be the best choice to preserve immunological parameters and the antioxidant activity of human milk.

Aroma characteristics of cloudy kiwifruit juices treated with high hydrostatic pressure and representative thermal processes

The commercial kiwifruit juice is deficient in a theoretical basis for the control of aroma characteristics during sterilization. To investigate the different sterilization methods on the aroma of kiwifruit juice, three sterilized kiwifruit juice samples, including pasteurization (PS), high temperature short time (HTST) and high hydrostatic pressure (HHP) sterilization, were observed. Results showed that a total of 15 major aroma-active compounds were identified in fresh kiwifruit juice by combination of detection frequency (DF) analysis and odor activity value (OAV); while the changes of these aroma-active compounds during PS, HTST and HHP sterilization were further studied. Quantitative descriptive analysis (QDA) was applied to validate the sensory differences, showing fruity and grassy notes changed a lot after sterilization, and the HHP sample was similar to fresh sample (FS) in comparison of samples treated by other sterilization methods. Further partial least squares regression analysis (PLSR) coincided with the overall note. Among these aroma-active compounds, the decrease of C6 aldehydes and C6 alcohols such as hexanal, (E)-2-hexenal and 1-hexanol might result in the great change of grassy note while the change of fruity note might be well correlated with the decrease of esters such as methyl butyrate and ethyl butyrate during processing.

Application of high pressure processing to improve digestibility, reduce allergenicity, and avoid protein oxidation in cod (Gadus morhua)

In this study, comprehensive analysis was performed to evaluate the impact of high hydrostatic pressure (HHP) and traditional thermal processing methods (baking and steaming) on cod proteins. Results showed that HHP, but not baking or steaming, was able to increase the content of soluble protein nitrogen (1.42-fold), compared with control. Total peptide contents of HHP-treated samples were also significantly higher than baked and steamed ones. In addition, protein oxidation was greatly increased after baking (1.56-fold) and steaming (1.97-fold), whereas HHP did not exhibit any appreciable effect. Furthermore, the allergenicity of cod was significantly reduced after HHP as reflected by the attenuated IgE and IgG-binding capacities (67–84% relative to control), while baking and steaming resulted in higher allergenicity. This study strongly supports the potential of HHP for reducing allergenicity, avoiding protein oxidation, and improving digestibility of cod and other protein-rich foods susceptible to quality deterioration during thermal processing.

Preference-based multi-objectivization applied to decision support for High-Pressure Thermal processes in food treatment

Food industry aims to provide healthy products that must satisfy the quality requirements of the considered legislation. To do so, food is treated by using some processing techniques, such as High-Pressure Thermal (HPT) treatments. In this work, we propose a preference-based multi-objectivization methodology to design HPT processes for food treatment. This approach is based on formulating a multi-objective optimization problem, instead of a constrained mono-objective problem, where the constraints are reformulated as separate objective functions. The multi-objective problem is then solved by using preference-based evolutionary optimization algorithms (PMOEAs). PMOEAs focus the search of a numerical solution inside a region of interest defined by the food engineer, avoiding exploring HPT designs that are out of interest. The proposed methodology is validated by considering several particular mono-objective and multi-objective optimization problems related to HPT processing. In particular, we compare the results obtained by two competitive state-of-the-art PMOEAs, called WASF-GA and R-NSGA-II, with the ones returned by a mono-objective algorithm called MLS-GA. As part of this study, the influence of the optimization algorithm parameters on the solutions, their quality and the computing time are discussed. Finally, the best solutions returned by the algorithm that shows a better performance for our problems, which is WASF-GA, are analyzed from a food engineering point of view and a sensitivity analysis regarding the impact of design parameters on the performances of those solutions is carried out.

Application of microwave-irradiation technique in deglycosylation of ginsenosides for improving apoptosis induction in human melanoma SK-MEL-2 cells

To increase the contents of medicinally effective ginsenosides, we used high-temperature and high-pressure thermal processing of ginseng by exposing it to microwave irradiation. To determine the anti-melanoma effect, the malignant melanoma SK-MEL-2 cell line was treated with an extract of microwave-irradiated ginseng. Microwave irradiation caused changes in the ginsenoside contents: the amounts of ginsenosides Rg1, Re, Rb1, Rb2, Rc, and Rd were disappeared, while those of less polar ginsenosides, such as Rg3, Rg5, and Rk1, were increased. In particular, the contents of Rk1 and Rg5 markedly increased. Melanoma cells treated with the microwave-irradiated ginseng extract showed markedly increased cell death. The results indicate that the microwave-irradiated ginseng extract induced melanoma cell death via the apoptotic pathway and that the cytotoxic effect of the microwave-irradiated ginseng extract is attributable to the increased contents of specific ginsenosides.

The Inactivation Kinetics of Soluble and Membrane-Bound Polyphenol Oxidase in Pear during Thermal and High-Pressure Processing

Polyphenol oxidase (PPO) from pear was characterized with catechol as substrate. The Michaelis constant of soluble and membrane-bound PPO were 15.6 and 23.8 mM, respectively, and their optimum pH for activity were 6.0 and 6.5, respectively. The inactivation kinetics of soluble and membrane-bound PPO during thermal (45–75 °C) and high-pressure thermal processing (600 MPa, 40–80 °C) were studied. The inactivation kinetics of pear PPO were described by a first-order model at all processing conditions. Compared to soluble PPO, membrane-bound PPO was more sensitive to thermal and high-pressure inactivation. Both soluble and membrane-bound PPO displayed higher sensitivity towards thermal inactivation at pH 3.5 (pH of pear puree made from pears dipped in citric acid prior to blending) compared to pH 4.4 (pH of non-acidified pear puree). High pressure and temperature had synergistic inactivation effects on pear PPO at pH 4.4 while slight antagonistic effects were observed at pH 3.5.

Differences in the resistance of microbial spores to thermosonication, high pressure thermal processing and thermal treatment alone

Bacterial and fungal spores can survive pasteurization treatments, and germinate/grow after food processing, causing food spoilage and/or outbreaks. High pressure processing (HPP) and power ultrasound technologies can be combined with heat (HPP-thermal or HPTP, TS) to increase the rate of spore inactivation. In this study, the differences in the resistance of bacterial and mould spores of several microbial species to thermal, 600 MPa HPP-thermal, and TS (0.33 W/mL or g) treatments were investigated. Thermal processes in the range of 70–78 °C almost did not affect the five microbial species’ spores tested (<1 log after 40 min). On the contrary, 600 MPa-75 °C HPP treatment reduced all microbial spores (2.8 to >5.8 log after 40 min): C. perfringens presented the highest resistance, followed by B. nivea and N. fischeri moulds, and lastly B. cereus. TS treatments (70–75 °C) up to 60 min had almost no effect on A. acidoterrestris and C. perfringens, while B. cereus in beef slurry was readily inactivated (6 log after 2 min). Activation shoulders were registered for both moulds. As opposed to HPP-thermal and thermal treatments, the type of food had a significant effect in the spore inactivation by TS.

Non-linear pressure/temperature-dependence of high pressure thermal inactivation of proteolytic Clostridium botulinum type B in foods.

The effect of high pressure thermal (HPT) processing on the inactivation of spores of proteolytic type B Clostridium botulinum TMW 2.357 in four differently composed low-acid foods (green peas with ham, steamed sole, vegetable soup, braised veal) was studied in an industrially feasible pressure range and temperatures between 100 and 120°C. Inactivation curves exhibited rapid inactivation during compression and decompression followed by strong tailing effects. The highest inactivation (approx. 6-log cycle reduction) was obtained in braised veal at 600 MPa and 110°C after 300 s pressure-holding time. In general, inactivation curves exhibited similar negative exponential shapes, but maximum achievable inactivation levels were lower in foods with higher fat contents. At high treatment temperatures, spore inactivation was more effective at lower pressure levels (300 vs. 600 MPa), which indicates a non-linear pressure/temperature-dependence of the HPT spore inactivation efficiency. A comparison of spore inactivation levels achievable using HPT treatments versus a conventional heat sterilization treatment (121.1°C, 3 min) illustrates the potential of combining high pressures and temperatures to replace conventional retorting with the possibility to reduce the process temperature or shorten the processing time. Finally, experiments using varying spore inoculation levels suggested the presence of a resistant fraction comprising approximately 0.01% of a spore population as reason for the pronounced tailing effects in survivor curves. The loss of the high resistance properties upon cultivation indicates that those differences develop during sporulation and are not linked to permanent modifications at the genetic level.

Effect of citric acid and high pressure thermal processing on enzyme activity and related quality attributes of pear puree

Abstract Pear puree was acidified with citric acid and was subjected to thermal (TP) and high pressure-thermal processing (HPTP). Citric acid inhibited peroxidase (POD) and polyphenol oxidase (PPO) and preserved the color of pear puree. The addition of citric acid (2%, w/w) increased total phenolic content (TPC) and oxygen radical absorbance capacity (ORAC) of pear puree by ~ 50%. POD was more sensitive than PPO to thermal and HPT inactivation. Citric acid enhanced thermal and HPT inactivation and complete inactivation of POD was observed after TP (90 °C, 7 min) and HPTP (600 MPa, 90 °C, 5 min) in acidified samples, while a maximum 60% inactivation of PPO was observed under these conditions. TP resulted in a slightly better color retention of acidified samples than HPTP under conditions of equivalent enzyme inactivation, whereas TPC and ORAC remained stable irrespective of the process. Industrial relevance This study investigated the effect of thermal and high pressure thermal processing with and without citric acid on the activity of oxidative enzymes and related quality attributes of pear puree. Citric acid inhibited enzymatic browning, protected polyphenolic antioxidants against oxidative degradation and resulted in 50% increase in antioxidant capacity when it was added at 2% (w/w). Acidified pear puree can possibly be used as an ingredient in products such as yoghurts, jams and baby food after either thermal or high pressure thermal processing due to its reduced oxidative enzyme activity, low pH, high antioxidant capacity and excellent color retention.

Application of innovative technologies, moderate-intensity pulsed electric fields and high-pressure thermal treatment, to preserve and/or improve the bioactive compounds content of pumpkin

Abstract The application of novel technologies such as moderate-intensity pulsed electric fields (MIPEF) and/or high pressure thermal (HPT) treatments improved the quality of processed pumpkin. MIPEF was applied to whole pumpkin in order to increase the bioactive compounds content, in contrast, HPT treatment was applied in order to preserve the purees. Traditional thermal treatment (TT) of pasteurization and sterilization was compared with equivalent HPT treatments. The effect of processing (TT vs. HPT) in purees made from pumpkin pretreated with MIPEF was evaluated. Microbiological counts, enzyme inactivation (polyphenol oxidase, PPO) and bioactive compounds content (carotenoids, phenolic compounds and antioxidant activity) were analyzed in all processed purees. Regarding the pretreatment of the pumpkin, the application of MIPEF increased the content of some bioactive compounds of interest, such as carotenoids. The HPT treatment equivalent to sterilization preserved high levels of carotene compounds and antioxidant activity of pumpkin puree although this treatment importantly modified the original color of puree. However, the HPT treatment equivalent to pasteurization did not inactivate PPO enzyme in contrast to the effect reached by the equivalent TT. The bioactive compounds levels in HPT treated puree were similar or lower than those treated by TT. Industrial relevance Pulsed electric fields and high pressure thermal processing are emerging non-thermal food processing technologies. Moderate-intensity pulsed electric fields (MIPEF) were applied to increase the generation of bioactive compounds in vegetables. This treatment enhanced the carotenoids content in pumpkin. High pressure thermal treatment (applied at conditions equivalent to sterilization) was the method that best preserved pumpkin purees. The application of MIPEF to pumpkin and HPT treatment to the resulting purees could be proposed as a strategy for producing and preserving vegetable products with high bioactive compounds content.

Comparing high pressure thermal processing and thermosonication with thermal processing for the inactivation of bacteria, moulds, and yeasts spores in foods

Bacterial and fungal spores might germinate/grow after food processing, causing food-borne diseases or food spoilage. High pressure processing (HPP) and power ultrasound are two technologies that can be combined with heat (HPP-thermal or HPTP, TS) to increase the rate of spore inactivation. The objective of this study was to compare HPP, HPTP and TS with exclusively thermal processing to inactivate spores of two pathogenic bacteria (Clostridium perfringens, Bacillus cereus) as well as fruit spoilage microorganisms (Alicyclobacillus acidoterrestris bacteria, Byssochlamys nivea and Neosartorya fischeri moulds, and Saccharomyces cerevisisae yeast). For a 20 min process at 75 °C, 600 MPa HPTP was the best technology for the inactivation of spores of C. perfringens in beef slurry (2.2 vs. 0.9 log for 0.33 W/g TS and no inactivation for thermal treatment). Likewise, at 70 °C 600 MPa HPTP was better to inactivate B. cereus spores in milk than single thermal treatment (4.0 vs. 0.3 log after 20 min process). At 75 °C 600 MPa HPTP was also the best technology for the inactivation of mould ascospores of N. fischeri in apple juice (4.3 log) and B. nivea in strawberry puree (2.0 log) vs. no effect for thermal and even increase in the spores with TS after a 20 min process. TS was a better technology than thermal treatment to reduce A. acidoterrestris spores in orange juice (0.6 vs. 0.2 log after 20 min at 78 °C). Regarding S. cerevisiae ascospores inactivation in beer, non-thermal HPP was much better than TS and thermal processing: 3 log reductions required only 30 s at 400 MPa vs. 5 min for 16.2 W/mL-TS-55 °C and 84 min for 55 °C thermal. Overall, the heat assisted HPP technology was better than TS and thermal treatment alone for the inactivation of bacteria, mould, and yeast spores, requiring lower processing times thus allowing a better food quality.

Resistance of Byssochlamys nivea and Neosartorya fischeri mould spores of different age to high pressure thermal processing and thermosonication

Byssochlamys nivea and Neosartorya fischeri are heat resistant moulds that spoil acid foods and can produce mycotoxins. This study investigated the efficacy of 600 MPa high pressure thermal processing (HPTP) and thermosonication (TS, 24 kHz, 0.33 W/mL) at 75 °C for the inactivation of 4–12 week old ascospores of B. nivea in strawberry puree and N. fischeri in apple juice. Spore resistance increased with increasing age for both species, with differences in the extent of inactivation of up to 2 log between spore age groups. HPTP was more effective than TS for spore inactivation. The 12 week B. nivea and N. fischeri spores had similar resistance to HPTP. TS caused increase in spore numbers, which was more pronounced for N. fischeri. The kinetics of mould ascospore inactivation by HPTP and TS were well described by Weibull and Lorentzian models, respectively. The Weibull's scale factor b decreased with spore age for N. fischeri, and the Lorentzian parameter b also decreased with spore age for both moulds, indicating more resistance. The results demonstrated that mould spore age is an issue for fruit product manufacturers, since spores contaminating fruits can be very old, exhibiting higher resistance.

Past, Present and Future of Military Food Technology

Food technology has been instrumental in ensuring that troops remain fit to fight. Early food technologies produced flat bread, hard biscuits, cheese and salted meat, allowing Roman legionaries to carry rations for several days. Canning was invented in the late 18th century in response to the French Government’s offer of a substantial reward to the person whose invention would allow troops to carry their food when marching long distances. World War II saw further advances in the form of stable and palatable canned meals, compressed cereal bars, candy-coated peanuts and other innovative foods in US combat rations. Two significant technology breakthroughs in the second half of the 20th century have altered the form of military rations. Freeze drying matured as an industrial technology, allowing the production of long-life, light-weight rations. Flexible packaging, based on plastic laminates, led to reduced weight and less waste disposal through the development of retort pouched meals (meals in flexible packaging that have undergone heat sterilization), which have largely replaced metal cans in combat rations. Improvements in quality of military rations, particularly their organoleptic properties, are emerging through application of innovative technologies such as high-pressure thermal processing, pulsed electric field, and microwave assisted thermal sterilization. Research and development of functional foods, such as those containing added essential fatty acids or probiotics offers the potential to provide combat rations that can further improve soldier health and performance.

Quality change during high pressure processing and thermal processing of cloudy apple juice

This work evaluates the impact of high pressure processing (HPP; 600 MPa, 3 min) on apple (Pink Lady, Granny Smith and Jonagold) juice quality changes compared to thermal processing (TP; P8.3 °C 85 °C =5min). This comparative study was performed by integrating both an untargeted headspace-GC-MS fingerprinting and targeted approach to analyze the volatile fraction and a priori selected quality attributes (color, sugars, acids and enzymes) respectively. A significant higher total color difference (ΔE* >6.0) was determined for thermally treated juice. Polyphenol oxidase and peroxidase can be inactivated below detection limits by TP, while residual activity (>50%) was detected after HPP. Sugars and acids were almost not affected nor by HPP nor by TP. Using the untargeted fingerprinting approach, aldehydes, alcohols, ketones and organosulfur were detected in higher amounts after TP compared to untreated and HPP treated samples, which could be linked to the Maillard reaction and oxidative reactions. In general, the overall quality of HP treated apple juices is much more comparable to that of the fresh juice, in particular HPP results in lower amount of thermally induced compounds that are related to cooked notes of pasteurized apple juices.

Effect of high pressure thermal processing on the quality attributes of Aloe vera-litchi mixed beverage

Abstract Sensory evaluation of four different formulations of Aloe vera -litchi mixed fruit beverage (ALMB) was carried out by a semi-trained sensory panel, and the corresponding sensory data was considered for similarity analysis using fuzzy logic. Based on the similarity analysis, the optimum formulation of ALMB was selected with litchi juice (85%): Aloe vera juice (15%, v/v). Further, the effect of high pressure thermal processing (HPTP) on the quality attributes namely physicochemical, nutritional, enzyme activity and the microbial population was evaluated within the domain of 400–600 MPa/30–60 °C/0–15 min as processing condition. The physicochemical properties such as pH, TSS and acidity of ALMB were minimally affected by HPTP, whereas, the loss of ascorbic acid up to 40% and the natural color of the ALMB samples was affected. The increased extractability of phenolics and antioxidants was observed for the samples treated at all the pressures and temperature up to 50 °C. Pectinmethylesterase (PME) was found to be the most baro-resistant enzyme with the maximum inactivation of up to 54% followed by peroxidase (POD) (72%) and polyphenoloxidase (PPO) (82%). The microbial inactivation during the isobaric period was well described by the first-order model (R 2 > 0.82); yeast and mold group was found to be the most baro-resistant among the entire studied natural microflora. Industrial relevance The present study gives information on fuzzy logic based similarity analysis technique for ranking of different fruit based formulation as well as ranking of its quality attributes. This technique can be used by the industry to process the linguistic data of sensory analysis and make appropriate decisions for product development. High pressure thermal processing can be efficiently used to develop high quality beverage products.

High pressure thermal processing for the inactivation of Clostridium perfringens spores in beef slurry

The spores of Clostridium perfringens can survive and grow in cooked/pasteurized meat, especially during the cooling of large portions. In this study, 600 MPa high pressure thermal processing (HPTP) at 75 °C for the inactivation of C. perfringens spores was compared with 75 °C thermal processing alone. The HPTP enhanced the inactivation of C. perfringens spores in beef slurry, resulting in 2.2 log reductions for HPTP vs. no reductions for thermal processing after 20 min. Then, the HPTP resistance of two C. perfringens spore strains in beef slurry at 600 MPa was compared and modeled, and the effect of temperature investigated. The NZRM 898 and NZRM 2621 exhibited similar resistance, and Weibull modeled well the log spore survivor curves. The spore inactivation increased when HPTP temperature was raised from 38 to 75 °C. The results confirm the advantage of high pressure technology to increase the thermal inactivation of C. perfringens spores in beef slurry. C. perfringens spores may cause food/meat poisoning as a result of improperly handled and prepared foods in industrial kitchens. Thermal processes at 100 °C or higher are generally carried out to ensure the elimination of these pathogenic spores. High pressure processing (HPP) is a food pasteurization technique which would help to maintain the sensorial and nutritional properties of food. Preservation of foods with HPP in conjunction with mild heat (HPTP) would enhance the spore inactivation compared to thermal processing alone at the same temperature, due to a known germination–inactivation mechanism. This technology, together with the application of Good Manufacturing Practices, including rapid cooling, is a good alternative to the traditional methods for producing safe processed meat and poultry products with enhanced sensory and nutritional quality.

High pressure thermal processing of pears: Effect on endogenous enzyme activity and related quality attributes

Abstract The effect of high pressure-thermal (HPT) processing (600 MPa, 20–100 °C) on the activity of pear enzymes and related quality attributes was investigated. HPT processing at 20 °C for 5 min resulted in 32%, 74% and 51% residual activities of polyphenol oxidase (PPO), peroxidase (POD) and pectin methylesterase (PME), respectively. Increasing processing temperature to 40 and 60 °C reduced the level of PPO and POD inactivation, with the maximum residual activities of 64% and 123%, respectively observed after 3-min treatments at 40 and 60 °C. Overall, HPT at 20 to 60 °C had minimal effect on quality, although enzymatic browning was observed upon air exposure. HPT at 80 to 100 °C caused almost complete inactivation of PPO and POD with 90% and 92% inactivation respectively after 3-min processing at 100 °C, which reduced browning upon air exposure. Nevertheless, the lowest texture retention of 22% was observed under this condition. Industrial relevance The study examined the effects of combined high pressure thermal processing on quality related pear enzymes and related instrumental quality attributes such as colour and texture. The study enabled identification of processing regimes for enzyme inactivation and quality retention. The excellent quality retention following HPP at 20 to 40 °C makes this condition suitable for ‘fresh-like’ small portion products for immediate consumption after unpacking that do not require complete PPO and POD inactivation. On the other hand, the almost complete inactivation of oxidative enzymes PPO and POD at 100 °C makes this condition more appropriate for the production of bulk products for food service applications or pureed ingredients for baby food, or pear pieces for yoghurt, that require PPO inhibition but not necessarily high firmness retention.