Comparative evaluation of the effects of pulsed electric field and freezing on cell membrane permeabilisation and mass transfer during dehydration of red bell peppers

The extent of cell membrane permeabilisation due to high intensity electric field pulses (HELP) varying number of pulses (1–50) using electric field of 2 kV/cm, 400 μs pulse duration and freezing on mass transfer and vitamin C content during osmotic (50° Brix sucrose at 40 °C) and convective air (60 °C, 1 m/s for 5 h) dehydration of red bell peppers was studied. Total pore area due to HELP increased with number of pulses while freezing resulted in total pore area of almost 6 times as greater as the highest value from the HELP process. Higher water loss was observed for all HELP treated than for prefrozen samples while slow freezing provided samples with the highest solids uptake. The correlation coefficient (R²) of linear regression between water loss and solids gain estimated from either total solids or soluble solids measurement ranged from 0.954 to 0.998 suggesting the possibility of using the soluble solids method in evaluating mass transfer kinetics during osmotic dehydration process. Drying rate during convective air-drying was more enhanced by HELP than by freezing. Electrical conductivity of the osmotic solution increased with the degree of permeabilisation to a given medium value after which no further increase in the release of the intracellular ions was observed. Minimal vitamin C depletion was observed immediately after HELP treatment. The order of magnitude of vitamin C retention was untreated>frozen>HELP pretreated samples with 1 pulse>5 pulses>50 pulses>10 pulses>20 pulses after osmotic dehydration. The reduction in vitamin C content of HELP treated samples after convective drying ranged from approximately 11 to 24% while freezing resulted in approximately 24% decrease compared to the untreated samples.     

Impact of high intensity electric field pulses on cell permeabilisation and as pre-processing step in coconut processing

The impact of high intensity electric field pulses (HELP) for cell permeabilisation of coconut was studied. A preliminary investigation of suitable field strength and total energy input for HELP treatment (field strength, 0.1–2.5 kV/cm, number of pulses, 0–200, pulse width, 575 μs and pulse frequency 1 Hz) was carried out. A comparison of the HELP process (E=2.5 kV/cm, n=20 pulses, t=575 μs and frequency 1 Hz) was made with other methods of cell disintegration (e.g. mechanical rupture, thermal treatment, freeze-thaw cycle) on the yield of coconut milk obtained and its protein and fat contents. A combination of HELP treatment and centrifugation (10 000×g for 10 min) was employed as pre-processing step prior to coconut dehydration in a fluidised bed dryer (60°C, air velocity 1 m/s) in an attempt to enhance drying rates. Treatment with HELP under suitable conditions (E=2.5 kV/cm, n=20 pulses, t=575 μs and frequency 1 Hz) resulted in 20% increase in milk yield with reference to the untreated samples. The fat contents of the extracted milk from HELP treated and untreated samples were 58.0% and 61.2%, respectively, and the corresponding protein contents of the aqueous medium after separation by centrifugation were 50.0% and 51.6%. The combination of HELP and centrifugation step resulted in a reduction of approximately 22% of the drying time as compared to the untreated samples which could be of advantage in the production of copra.     

Kinetics of osmotic dehydration of red bell peppers as influenced by pulsed electric field pretreatment

This study was aimed at relating diffusion rates during osmotic dehydration of red bell peppers in two different osmotic solutions (sucrose/sodium chloride, 21.86 and 2.02 g/100 g respectively, and sucrose, 50°Brix at 30 °C) to the extent of membrane permeabilisation induced by pulsed electric field (PEF) using varying field strength of 1, 1.5 and 2 kV/cm with a constant pulse number of 20 at a pulse duration of 400±50 μs. The development of pores with time within the membrane after PEF was monitored, changes in sample weight and composition in the product liquid phase were analysed. The initiation of pore formation and pore growth within the cell membrane after PEF was found to be time dependent and not an instantaneous process. A fractional ruptured membrane area, F_p=0.003% was detected after about 20 s of application of 2 pulses at 2 kV/cm (320 J/kg energy input per pulse and approx. 0.2 °C temperature change) and this increased to 0.0166% within 300 min. Osmotic dehydration of bell peppers was highest at the beginning of the process. The application of PEF resulted in enhanced rate of transfers as indicated by an increase of 11–25% in water loss and 2–5% in solids gain as compared to the untreated samples in the two osmotic solutions. Conditions of PEF that induced an average fractional ruptured area of 0.008%, 5 min after PEF treatment were found adequate to markedly improve diffusion kinetics during the osmotic dehydration under atmospheric pressure conditions.     

Anwendung elektrischer Hochspannungsimpulse als Vorbehandlungsverfahren zur Beeinflussung der Trocknungscharakteristika und Rehydratationseigenschaften von Kartoffelwürfeln

High intensity electric field pulses as pretreatment for affecting dehydration characteristics and rehydration properties of potato cubes. High intensity electric field pulse (HELP) treatment was evaluated as pretreatment to possibly affect dehydration and rehydration characteristics of potato cubes (1 × 1 × 1 cm). Effects of electric field strength E = 0.35-3.0 kV · cm^?1 and number of pulses n = 1-70 on the degree of permeabilization of potato cells was evaluated using a centrifugal method. Optimization of E and n regarding maximum permeabilization of cells was performed. Energy requirements were found to be low (6.4-16.2 kJ · kg^?1) resulting in an increase in temperature in the treated product of _ΔT = 1.8-4.5°C. The HELP treatment enabled a maximum degree of permeabilization and resulted in a cell liquid release from potato cubes after centrifugation (700 × g) to up to 27-29% (untreated control 0%) as related to total water content. Treatment with optimum parameters (E = 0.9-2.0 kV · cm^?1, n = 15-30) resulted in improved mass transfer within the product and drying time during fluidized bed drying (T_tr = 55°C, 70°C, air velocity 2 m · s^?1) of potato cubes could be reduced to up to 20-25%. Rehydration properties and quality characteristics of the products after cooking were not affected by the high intensity electric field pulse pretreatment.     

Effect of temperature, pressure and calcium soaking pre-treatments and pressure shift freezing on the texture and texture evolution of frozen green bell peppers (Capsicum annuum)

The firmness of green bell pepper (Capsicum annuum) was studied under different processing conditions. Thermal texture degradation kinetics of pepper tissue between 75 and 95 °C could be accurately described by a fractional conversion model. The firmness of pre-processed pepper increased when the samples were submitted to several heat, pressure, and combinations of heat/pressure and calcium soaking pre-treatments. Pre-heating at 55 °C during 60 min and mild heat/high-pressure treatments (200 MPa at 25 °C, 15 min) yielded the best results, which were further improved when combined with calcium soaking. These pre-treatments significantly slowed down thermal texture degradation of pepper at 90 °C, a typical temperature used for pepper blanching prior to freezing. The above-mentioned pre-treated samples showed a significant reduction in firmness when frozen by regular freezing at 0.1 MPa. The same samples showed no changes in firmness when frozen by high-pressure shift freezing at 200 MPa. When freezing was carried out by high-pressure shift and after frozen storage (−18 °C) for 2.5 months, pressure pre-treated pepper showed a better retention of texture than thermal pre-treated pepper.     

Important factors to consider for acrylamide mitigation in potato crisps using pulsed electric fields

This preliminary study aimed to compare the application of pulsed electric field (PEF) with a traditional blanching as pre-treatments before frying for the mitigation of acrylamide content in potato crisps.Measuring the degree of cell disintegration index (p_o) and the changes in water electrical conductivity during washing of potato slices, PEF protocol and sample preparation scheme were optimized. Peeled potato slices (thickness 1.5 ± 0.2 mm) were subjected to PEF (1.5 kV/cm, pulse duration 10 μs, total treatment time 10 ms, pulse frequency 100 Hz) and to blanching (85 °C for 3.5 min) pre-treatments and then to washing in water, evaluating the reduction of acrylamide precursors (reducing sugars and free asparagine). After frying (175 °C, 3 min), product quality, in terms of colour, texture and acrylamide content were evaluated. Results showed that PEF promoted acrylamide precursors leaching followed by a reduction of the final acrylamide content of around 30%, significantly higher if compared to the reduction obtained with blanching, with only slight modifications of the final quality of the product, in terms of colour and texture.Industrial relevanceThe Commission Regulation (EU) 2017/2158 of 20 November 2017 has introduced new benchmark levels and mitigation strategies for the reduction of the presence of acrylamide in foods, directing food businesses to the research of measures to lower the acrylamide formation in foods. The actual industrial production process of fried potato crisps involves the use of many mitigation strategies, such as a blanching of raw potatoes. However, the traditional blanching treatment presents several practical drawbacks and leads to undesirable changes of the product quality. The application of PEF as a pre-treatment could reduce the acrylamide content in deep-fat fried potato crisps. This preliminary study gives important indications regarding the possibility of combining a PEF pre-treatment on raw potato slices with subsequent industrial processing steps for the production of potato crisps with low acrylamide concentration.     

Comparative study on shelf life of orange juice processed by high intensity pulsed electric fields or heat treatment

The effects of high intensity pulsed electric fields (HIPEF) processing (35 kV/cm for 1,000 μs; bipolar 4-μs pulses at 200 Hz) on the microbial shelf life and quality-related parameters of orange juice were investigated during storage at 4 and 22 °C and compared to traditional heat pasteurization (90 °C for 1 min) and an unprocessed juice. HIPEF treatment ensured the microbiological stability of orange juice stored for 56 days under refrigeration but spoilage by naturally occurring microorganisms was detected within 30 days of storage at 22 °C. Pectin methyl esterase (PME) of HIPEF-treated orange juice was inactivated by 81.6% whereas heat pasteurization achieved a 100% inactivation. Peroxidase (POD) was destroyed more efficiently with HIPEF processing (100%) than with the thermal treatment (96%). HIPEF-treated orange juice retained better color than heat-pasteurized juice throughout storage but no differences (p<0.05) were found between treatments in pH, acidity and °Brix. Vitamin C retention was outstandingly higher in orange juice processed by HIPEF fitting recommended daily intake standards throughout 56 days storage at 4 °C, whereas heat-processed juice exhibited a poor vitamin C retention beyond 14 days storage (25.2–42.8%). The antioxidant capacity of both treated and untreated orange juice decreased slightly during storage. Heat treatments resulted in lower free-radical scavenging values but no differences (p<0.05) were found between HIPEF-processed and unprocessed orange juice.     

The effect of blanching on the quality of dehydrated broccoli florets

Different blanching treatments were applied to broccoli florets prior to dehydration in order to improve product quality. The pretreatments used were a conventional blanching in water at 99ǃ °C, and a stepwise blanching (a blanching at low temperature followed by a short blanching at high temperature after a holding time) using different temperatures for the first step (50, 55, 60, 65 and 70 °C). Five rehydration temperatures were used (25, 40, 55, 65 and 80 °C). Rehydration rate (D_eff and W_e), chlorophyll content and texture of the rehydrated product were evaluated. Rehydration was modelled according to Fick's diffusion equation. A good agreement between the model and the experimental data was obtained when D_eff and W_e values were identified for each temperature (average explained variance 96.9%). Samples stepwise blanched at 60 °C showed, on the average, the lowest W_e values. Stepwise blanching at 60-65 °C and rehydration at 25-55 °C were the combinations that gave the firmest product. Stepwise blanching at 50 °C together with the conventional blanching (99ǃ °C) and rehydration between 25 and 65 °C were the combinations that allowed preservation of the highest chlorophyll content. From these results, it seems difficult to obtain firm samples with a high chlorophyll content without additives.     

Ohmic heating and pulsed vacuum effect on dehydration processes and polyphenol component retention of osmodehydrated blueberries (cv. Tifblue)

Blueberries are highly perishable fruits; therefore, emerging technologies focus on improving the bioactive compound retention and extending the shelf life. The aim of this study was to evaluate the effect of ohmic heating and vacuum pulses on the dehydration processes and polyphenol compound retention of osmodehydrated blueberries (cv. Tifblue). The treatments were performed using a 65% (w/w) sucrose solution, an electric field of 13 V/cm (100 V) at 30 °C, 40 °C or 50 °C for 300 min, and air drying at 50, 60 or 70 °C to obtain dried blueberries. The moisture content, soluble solids and phenolic compounds were analyzed. The combination of ohmic heating/pulsed vacuum treatments intensifies mass transfer in osmodehydrated blueberries, especially at higher temperatures. Nevertheless, the polyphenol retention was greater at lower temperatures; hence, the application of an intermediate process temperature (40 °C) was selected as a pre-treatment prior to further drying. The treated samples improve the retention of polyphenols after drying compared with untreated samples. Therefore, the results of this research study suggest that the use of a pulsed vacuum and ohmic heating in the osmotic dehydration (PVOD/OH) treatment at 40 °C for 240 min and subsequent drying at 60°C could be the best process for dehydrating blueberries, considering that it improved mass transfer, achieved lower losses of phenolic components and reduced the drying time.Industrial relevanceBlueberries are an important fruit due their high bioactive compound content, especially polyphenols. Studies that involve emerging technologies application could add value to blueberries. Ohmic heating and pulsed vacuum as pre-treatments improve the efficiency of dehydration processes, focused toward bioactive compounds retention and achieving commercial viability. In this work have been applied PVOD/OH treatments at moderated temperatures and subsequently dried at 60 °C, obtaining promissory results.     

Assessing the Impact of High-Pressure Processing on Selected Physical and Biochemical Attributes of White Cabbage (Brassica oleracea L. var. capitata alba)

The aim of this study was to investigate the effect of combined pressure/temperature treatments (200, 400 and 600 MPa, at 20 and 40 °C) on key physical and chemical characteristics of white cabbage (Brassica oleracea L. var. capitata alba). Thermal treatment (blanching) was also investigated and compared with high-pressure processing (HPP). HPP at 400 MPa and 20–40 °C caused significantly larger colour changes compared to any other pressure or thermal treatment. All pressure treatments induced a softening effect, whereas blanching did not significantly alter texture. Both blanching and pressure treatments resulted in a reduction in the levels of ascorbic acid, effect that was less pronounced for blanching and HPP at 600 MPa and 20–40 °C. HPP at 600 MPa resulted in significantly higher total phenol content, total antioxidant capacity and total isothiocyanate content compared to blanching. In summary, the colour and texture of white cabbage were better preserved by blanching. However, HPP at 600 MPa resulted in significantly higher levels of phytochemical compounds. The results of this study suggest that HPP may represent an attractive technology to process vegetable-based food products that better maintains important aspects related to the content of health-promoting compounds. This may be of particular relevance to the food industry sector involved in the development of convenient novel food products with excellent functional properties.     

Application of PEF- and OD-assisted drying for kiwifruit waste valorisation

The production of dried snacks with high nutritional value represents a valid alternative to use the kiwifruit waste as undersized fruits, with a positive economic impact on the entire production chain. Therefore, this work aimed to evaluate the effect of pulsed electric field - PEF (200 V/cm) and/or osmotic dehydration – OD pre-treatments on drying kinetics (50, 60, 70 °C), texture, colour, and sensorial properties of yellow kiwifruit snacks. The drying kinetics were significantly influenced both by applied treatment and drying temperature. The firmness of the kiwifruit snacks was improved by the combination of PEF/OD pre-treatments. In general, drying temperature of 70 °C and the use of combined pre-treatments seem to be a good compromise to reduce drying time and obtain products with high quality in terms of colour, firmness, and overall acceptability.     

Inactivation of peroxidase and lipoxygenase in carrots, green beans, and green peas by combination of high hydrostatic pressure and mild heat treatment

The efficiency of high hydrostatic pressure (HHP) with the combination of mild heat treatment on peroxidase (POD) and lipoxygenase (LOX) inactivation in carrots, green beans, and green peas was investigated. In the first part of the study, the samples were pressurized under 250–450 MPa at 20–50 °C for 15–60 min. In the second part, two steps treatments were performed as water blanching at 40–70 °C for 15 and 30 min after pressurization at 250 MPa and 20 °C for 15–60 min. Carrot POD was decreased to 16% residual activity within the first 30 min at a treatment condition of 350 MPa and 20 °C and then it decreased to 9% at 60 min. When the carrots were water blanched at 50 °C for 30 min after HHP treatment of 250 MPa at 20 °C for 15 min, 13% residual POD activity was obtained. For green beans, the most effective results were obtained by two steps treatment and approximately 25% residual POD activity was obtained by water blanching at 50 °C for 15 min after pressurization at 250 MPa and 20 °C for 60 min. An effective inactivation of POD in green peas was not obtained. For carrots, LOX activity could not be measured due to very low LOX activity or the presence of strong antioxidants such as carotenoids. After pressurization at 250 MPa and 20 °C for 15 or 30 min, water blanching at 60 °C for 30 min provided 2–3% residual LOX activity in green beans. The treatment of 250 MPa for 30 min and then water blanching at 50 °C for 30 min provided 70% LOX inactivation in green peas.     

Influence of pulsed electric field-assisted dehydration on the volatile compounds of basil leaves

Pulsed electric field (PEF) was applied to basil leaves prior air drying at 40 °C. The parameters of the electric treatment were designed in such a way that (i) electroporated the tissue reversibly, provoking a permanent opening of the stomatal guard cells and (ii) electroporated the tissue irreversibly, damaging the cells. Treated leaves lost some volatile compounds due to both PEF treatments, probably related with the direct effect of permeabilization on the secretory cells of glandular trichomes. Upon drying, the irreversible permeabilization treatment showed the highest influence on the profile of volatiles in the dried leaves showing better retention of some terpenoids than the control. The performed statistical analysis allowed to select six compounds that can be used as markers both for the effect of pre-treatments prior dehydration and for the effects of dehydration itself on the volatile compounds of basil leaves.     

Application of thermal inactivation of enzymes during vitamin C analysis to study the influence of acidification,crushing and blanching on vitamin C stability in Broccoli (Brassica oleracea L var. italica)

The effectiveness of heat inactivation of oxidative enzymes e.g., ascorbic acid oxidase (AAO) to stabilise vitamin C during extraction and analysis was evaluated. The influence of different sequences of performing treatments including acidification (pH 4.3 vs. pH 6.5), crushing, high temperature short time (90 °C/4 min–HTST) and low temperature long time (60 °C/40 min–LTLT)) blanching on vitamin C stability in broccoli florets and stalks was also investigated. Heat inactivation of enzymes prior to matrix disruption resulted in higher vitamin C values mainly in L-ascorbic acid (L-AA) form, while lack of enzyme inactivation resulted in high vitamin C losses resulting from conversion of L-AA to dehydroascorbic acid. Various treatments and their sequence of application influenced vitamin C stability as follows: (i) crushing prior to blanching reduced vitamin C stability and (ii) in the absence of heating, acidification increased vitamin C stability (iii) blanching prior to crushing resulted in higher vitamin C retention, with HTST blanching retaining more vitamin C than LTLT blanching.     

THE USE OF PULSED ELECTRIC FIELDS IN PRODUCING JUICE FROM PAPRIKA (CAPSICUM ANNUUM L.)

Investigations were conducted on the impact of pulsed electric field (PEF) treatment on yield and some quality parameters of juice from paprika and results were compared to the results of juice obtained from enzymatically treated or untreated paprika mash. Paprika was comminuted mechanically after which the mash was subjected to either PEF (electric field strength = 1.7 kV/cm, pulse number = 30 and specific energy input per pulse = 0.5 kJ/kg) or a pectolytic enzyme preparation treatment. The extent of cell disintegration after the different pretreatments was monitored through cell disintegration index (Z_p) measurement prior to juice extraction through pressure (10 MPa for 4 min). Some quality parameters (pH, soluble solids (°Brix), total dry matter, color, total carotenoids as β-carotene and vitamin C) of the resultant juice samples were determined. PEF and enzyme treatments resulted in about 10% and 9% increase in juice yield, respectively. Juice from PEF treated paprika compared well in quality with enzyme treated or the untreated. And in some cases such as in color (redness, a value) of the juice, PEF treated had values (+ 18) higher than enzyme treated having + 15.5 and also in the amount of β-carotene extracted into the juice PEF treated juice had more than 60% as compared to about 44% from enzyme treated juice. The pH value for enzyme treated juice was lower than the others.     

Chemical Characteristics and Storage Stability of Pickled Garlic Prepared Using Different Processes

Three processes for preparing peeled pickled garlic were studied: (P) packing directly with an acidified brine, followed by pasteurization (90°C, 8 min); (B) blanching with hot water (90°C, 15 min) before packing, followed by a preservation treatment (pasteurization, preservatives + refrigeration); and (MB) same as B, except that microwave blanching was used (120g garlic cloves, 825W, 1.5 min). All products were microbiologically stable but fructans were hydrolyzed during storage at 27°C. A green pigment was also apparent in (P). Products from (B) or (MB) had better quality than that from (P). Most stable and best quality products resulted from the blanching treatments and water blanching resulted in the product with best color.     

Inactivation of orange juice peroxidase by high‐intensity pulsed electric fields as influenced by process parameters

The inactivation of orange juice peroxidase (POD) under high‐intensity pulsed electric fields (HIPEF) was studied. The effects of HIPEF parameters (electric field strength, treatment time, pulse polarity, frequency and pulse width) were evaluated and compared with conventional heat pasteurization. Samples were exposed to electric field strengths from 5 to 35 kV cm^?1 for up to 1500 µs using square wave pulses in mono‐ and bipolar mode. Effect of pulse frequency (50–450 Hz), pulse width (1–10 µs) and electric energy on POD inactivation by HIPEF were also studied. Temperature was always below 40 °C. POD was totally inactivated by HIPEF and the treatment was more effective than thermal processing in inactivating orange juice POD. The extent of POD inactivation depended on HIPEF processing parameters. Orange juice POD inhibition was greater when the electric field strength, the treatment time, the pulse frequency and the pulse width increased. Monopolar pulses were more effective than bipolar pulses. Orange juice POD activity decreased with electric energy density input. The Weibull distribution function adequately described orange juice POD inactivation as a function of the majority of HIPEF parameters. Moreover, reduction of POD activity related to the electric field strength could be well described by the Fermi model. Copyright © 2005 Society of Chemical Industry     

Multi-pulsed high hydrostatic pressure treatment for inactivation and injury of Escherichia coli

Escherichia coli cells in peptone water were pressurized at 300?MPa at ambient temperature with no holding time (pulse series) and with a total holding duration of 300?s for single- (300?s?×?1 pulse) and multi-pulsed (150?s?×?2 pulses, 100?s?×?3 pulses, 75?s?×?4 pulses, 60?s?×?5 pulses, 50?s?×?6 pulses and 30?s?×?10 pulses) high hydrostatic pressure (HHP) treatments. Multi-pulsed HHP treatment with no holding time indicated that as the pulse number increased the number of inactivated and injured cells also increased. Holding time had significant effect on the inactivation of E. coli. There was low inactivation difference between single- and multi-pulsed HHP treatments with holding time. Escherichia coli cells showed at least 1.6 log₁₀ more reduction on selective medium than the non-selective medium indicating that more than 95?% of the survivors severely injured for both single- and multi-pulsed treatments with holding time. Although the inactivation difference was low between single- and multi-pulsed HHP treatments, storage at 4?°C revealed that there was less recovery from injury for multi-pulsed HHP treatment.     

Effects of conventional and ultrasound blanching on enzyme inactivation and carbohydrate content of carrots

There is a growing interest in the use of ultrasound (US) as an alternative to conventional processes. Although US has previously been applied as a pretreatment of fruits and vegetables, no investigation has been done on the usefulness of US for carrot blanching, paying special attention to its effect on enzyme inactivation and leaching losses. In the present paper, the influence of US (in bath and with probe) on peroxidase (POD) and pectinmethylesterase (PME) inactivation and on the loss of total soluble solids and carbohydrates by leaching has been evaluated. Results of this preliminary study have also been compared with those obtained after conventional (hot water and steam) blanching of carrots. The highest enzyme inactivation was obtained with the conventional treatments performed at high temperatures and with the US probe treatments with heat generation. Carrots blanched by US probe for 10?min at a temperature up to 60?°C showed characteristics similar to those conventionally treated at 60?°C for 40?min. Although the efficiency of US was limited for total inactivation of POD and PME, this treatment resulted to be advantageous in terms of time for blanching at mild temperatures. US probe treatments could also be considered as an advantageous alternative to low-temperature long-time (LTLT) conventional treatments for those applications in which partial inactivation of PME is required for the better preservation of carrot structure.     

Processing of tomato: impact on in vitro bioaccessibility of lycopene and textural properties

BACKGROUND: Human studies have demonstrated that processing of tomato can greatly increase lycopene bioavailability. However, the difference between processing methods is not widely investigated. In the current study different thermal treatments of tomato were evaluated with regard to their impact on in vitro bioaccessibility and retention of lycopene and β‐carotene as well as textural properties. Thermal treatments used were low (60 °C) and high (90 °C) temperature blanching followed by boiling. RESULTS: Lycopene was relatively stable during thermal treatment, whereas β‐carotene was significantly (P < 0.05) reduced by all heat treatments except for low temperature blanching. In vitro bioaccessibility of lycopene was significantly increased from 5.1 ± 0.2 to 9.2 ± 1.8 and 9.7 ± 0.6 mg kg^?1 for low and high temperature blanching, respectively. An additional boiling step after blanching did not further improve lycopene bioaccessibility for any treatment, but significantly reduced the consistency of low temperature treated samples. CONCLUSION: Choice and order of processing treatments can have a large impact on both lycopene bioavailability and texture of tomato products. Further investigations are needed, but this study provides one of the first steps towards tomato products tailored to optimise nutritional benefits. Copyright © 2010 Society of Chemical Industry