Structure-function relationship of oat flour fractions when blended with wheat flour: Instrumental and nutritional quality characterization of resulting breads.

The present work investigated the structure-function relationship of dry fractionated oat flour (DFOF) as a techno-functional ingredient using bread as a model system. Mechanically, DFOF fractions (F), that is, F1: <224 µm, F2: 250-280 µm, F3: 280-500 µm, F4: 500-600 µm, and whole oat flour (F5) were blended with white wheat flour at 10%, 30%, and 50% substitution levels for bread making. The blended flours, doughs, and bread samples were assessed for their techno-functional, nutritional, and structural characteristics. The results of Mixolab and the Rapid Visco Analyzer show that the 50% substituted F3 fraction exhibits the highest water absorption properties (69.53%), whereas the 50% F1 fraction exhibits the highest peak viscosity of the past slurry. Analysis of bread samples revealed a lower particle size of DFOF fractions and higher supplementation levels, increased ß-glucan levels (0.13-1.29 g/100 bread (db), reduced fermentable monosaccharides, that is, glucose (1.44-0.33 g/100 g), and fructose (1.06-0.28 g/100 g). The effect of particle size surpassed the substitution level effect on bread volume reduction. The lowest hardness value for F1 is 10%, and the highest value for F2 is 50%. The total number of cells in the bread slice decreased from the control to the F4 fraction (50%). Multi-criteria analysis indicated that DFOF fractions produced breads with similar structure and higher nutritional value developed from white wheat flour. PRACTICAL APPLICATION: The use of mechanically fractionated oat flours fractions in white wheat flour breads can improve the nutritional profile without affecting the physical properties of the bread product. Based on the oat flour fractions, bakers and food processing companies can tailor the bread formulations for high ß-glucan, high fiber, and low reduced sugar claims.

Evaluation of Selenomethionine Entrapped in Nanoparticles for Oral Supplementation Using In Vitro, Ex Vivo and In Vivo Models.

Selenium methionine (SeMet) is an essential micronutrient required for normal body function and is associated with additional health benefits. However, oral administration of SeMet can be challenging due to its purported narrow therapeutic index, low oral bioavailability, and high susceptibility to oxidation. To address these issues, SeMet was entrapped in zein-coated nanoparticles made from chitosan using an ionic gelation formulation. The high stability of both the SeMet and selenomethionine nanoparticles (SeMet-NPs) was established using cultured human intestinal and liver epithelial cells, rat liver homogenates, and rat intestinal homogenates and lumen washes. Minimal cytotoxicity to Caco-2 and HepG2 cells was observed for SeMet and SeMet-NPs. Antioxidant properties of SeMet were revealed using a Reactive Oxygen Species (ROS) assay, based on the observation of a concentration-dependent reduction in the build-up of peroxides, hydroxides and hydroxyl radicals in Caco-2 cells exposed to SeMet (6.25-100 µM). The basal apparent permeability coefficient (Papp) of SeMet across isolated rat jejunal mucosae mounted in Ussing chambers was low, but the Papp was increased when presented in NP. SeMet had minimal effects on the electrogenic ion secretion of rat jejunal and colonic mucosae in Ussing chambers. Intra-jejunal injections of SeMet-NPs to rats yielded increased plasma levels of SeMet after 3 h for the SeMet-NPs compared to free SeMet. Overall, there is potential to further develop SeMet-NPs for oral supplementation due to the increased intestinal permeability, versus free SeMet, and the low potential for toxicity.

Formulation, Characterisation and Evaluation of the Antihypertensive Peptides, Isoleucine-Proline-Proline and Leucine-Lysine-Proline in Chitosan Nanoparticles Coated with Zein for Oral Drug Delivery.

Isoleucine-Proline-Proline (IPP) and Leucine-Lysine-Proline (LKP) are food-derived tripeptides whose antihypertensive functions have been demonstrated in hypertensive rat models. However, peptides display low oral bioavailability due to poor intestinal epithelial permeability and instability. IPP and LKP were formulated into nanoparticles (NP) using chitosan (CL113) via ionotropic gelation and then coated with zein. Following addition of zein, a high encapsulation efficiency (EE) (>80%) was obtained for the NP. In simulated gastric fluid (SGF), 20% cumulative release of the peptides was achieved after 2 h, whereas in simulated intestinal fluid (SIF), ~90% cumulative release was observed after 6 h. Higher colloidal stability (39−41 mV) was observed for the coated NP compared to uncoated ones (30−35 mV). In vitro cytotoxicity studies showed no reduction in cellular viability of human intestinal epithelial Caco-2 and HepG2 liver cells upon exposure to NP and NP components. Administration of NP encapsulating IPP and LKP by oral gavage to spontaneously hypertensive rats (SHR) attenuated systolic blood pressure (SBP) for 8 h. This suggests that the NP provide appropriate release to achieve prolonged hypotensive effects in vivo. In conclusion, chitosan-zein nanoparticles (CZ NP) have potential as oral delivery system for the encapsulation of IPP and LKP.

Salcaprozate sodium (SNAC) enhances permeability of octreotide across isolated rat and human intestinal epithelial mucosae in Ussing chambers.

Octreotide is approved as a one-month injectable for treatment of acromegaly and neuroendocrine tumours. Oral delivery of the octapeptide is a challenge due mainly to low intestinal epithelial permeability. The intestinal permeation enhancer (PE) salcaprozate sodium (SNAC) has Generally Regarded As Safe (GRAS) status and is a component of an approved oral peptide formulation. The purpose of the study was to examine the capacity of salcaprozate sodium (SNAC), to increase its permeability across isolated rat intestinal mucosae from five regions and across human colonic mucosae mounted in Ussing chambers. Apical-side buffers were Kreb's-Henseleit (KH), fasted simulated intestinal fluid (FaSSIF-V2), rat simulated intestinal fluid (rSIF), and colonic simulated intestinal fluid (FaSSCoF). The basal apparent permeability coefficient (Papp) of [3H]-octreotide was equally low across rat intestinal regional mucosae in KH, rSIF, and FaSSIF-V2. Apical addition of 20 mM SNAC increased the Papp across rat tissue in KH: colon (by 3.2-fold) > ileum (3.4-fold) > upper jejunum (2.3-fold) > duodenum (1.4-fold) > stomach (1.4-fold). 20 mM and 40 mM SNAC also increased the Papp by 1.5-fold and 2.1-fold respectively across human colonic mucosae in KH. Transepithelial electrical resistance (TEER) values were reduced in the presence in SNAC especially in colonic regions. LC-MS/MS analysis of permeated unlabelled octreotide across human colonic mucosae in the presence of SNAC indicated that [3H]-octreotide remained intact. No gross damage was caused to rat or human mucosae by SNAC. Attenuation of the effects of SNAC was seen in rat jejunal mucosae incubated with FaSSIF-V2 and rSIF, and also to some extent in human colonic mucosae using FaSSCoF, suggesting interaction between SNAC with buffer components. In conclusion, SNAC showed potential as an intestinal permeation enhancer for octreotide, but in vivo efficacy may be attenuated by interactions with GI luminal fluid contents.

The Statistical Optimisation of Recombinant ß-glucosidase Production through a Two-Stage, Multi-Model, Design of Experiments Approach.

ß-glucosidases are a class of enzyme that are widely distributed in the living world, with examples noted in plants, fungi, animals and bacteria. They offer both hydrolysis and synthesis capacity for a wide range of biotechnological processes. However, the availability of native, or the production of recombinant ß-glucosidases, is currently a bottleneck in the widespread industrial application of this enzyme. In this present work, the production of recombinant ß-glucosidase from Streptomyces griseus was optimised using a Design of Experiments strategy, comprising a two-stage, multi-model design. Three screening models were comparatively employed: Fractional Factorial, Plackett-Burman and Definitive Screening Design. Four variables (temperature, incubation time, tryptone, and OD600 nm) were experimentally identified as having statistically significant effects on the production of S.griseus recombinant ß-glucosidase in E. coli BL21 (DE3). The four most influential variables were subsequently used to optimise recombinant ß-glucosidase production, employing Central Composite Design under Response Surface Methodology. Optimal levels were identified as: OD600 nm, 0.55; temperature, 26 °C; incubation time, 12 h; and tryptone, 15 g/L. This yielded a 2.62-fold increase in recombinant ß-glucosidase production, in comparison to the pre-optimised process. Affinity chromatography resulted in homogeneous, purified ß-glucosidase that was characterised in terms of pH stability, metal ion compatibility and kinetic rates for p-nitrophenyl-ß-D-glucopyranoside (pNPG) and cellobiose catalysis.

Nutraceutical formulation, characterisation, and in-vitro evaluation of methylselenocysteine and selenocystine using food derived chitosan:zein nanoparticles.

Selenoamino acids (SeAAs) have been shown to possess antioxidant and anticancer properties. However, their bioaccessibility is low and they may be toxic above the recommended nutritional intake level, thus improved targeted oral delivery methods are desirable. In this work, the SeAAs, Methylselenocysteine (MSC) and selenocystine (SeCys2) were encapsulated into nanoparticles (NPs) using the mucoadhesive polymer chitosan (Cs), via ionotropic gelation with tripolyphosphate (TPP) and the NPs produced were then coated with zein (a maize derived prolamine rich protein). NPs with optimized physicochemical properties for oral delivery were obtained at a 6: 1 ratio of Cs:TPP, with a 1:0.75 mass ratio of Cs:zein coating (diameter ~260 nm, polydispersivity index ~0.2, zeta potential >30 mV). Scanning Electron Microscopy (SEM) analysis showed that spheroidal, well distributed particles were obtained. Encapsulation Efficiencies of 80.7% and 78.9% were achieved, respectively, for MSC and SeCys2 loaded NPs. Cytotoxicity studies of MSC loaded NPs showed no decrease in cellular viability in either Caco-2 (intestine) or HepG2 (liver) cells after 4 and 72 h exposures. For SeCys2 loaded NPs, although no cytotoxicity was observed in Caco-2 cells after 4 h, a significant reduction in cytotoxicity was observed, compared to pure SeCys2, across all test concentrations in HepG2 after 72 h exposure. Accelerated thermal stability testing of both loaded NPs indicated good stability under normal storage conditions. Lastly, after 6 h exposure to simulated gastrointestinal tract environments, the sustained release profile of the formulation showed that 62 ±â€¯8% and 69 ±â€¯4% of MSC and SeCys2, had been released from the NPs respectively.

Application of Box-Behnken experimental design for the formulation and optimisation of selenomethionine-loaded chitosan nanoparticles coated with zein for oral delivery.

Selenomethionine is an essential amino acid with a narrow therapeutic index and susceptibility to oxidation. Here it was encapsulated into a nanoparticle composed of chitosan cross-linked with tripolyphosphate for oral delivery. The formulation was optimised using a three-factor Box-Behnken experimental design. The chitosan:tripolyphosphate ratio, chitosan solvent pH, and drug load concentration were independently varied. The dependent variables studied were encapsulation efficiency, particle size, polydispersity index and zeta potential. For optimisation, encapsulation efficiency and zeta potential were maximised, particle diameter was set to 300 nm and polydispersity index was minimised. A 0.15 mg/mL concentration of selenomethionine, chitosan solvent pH of 3, and chitosan:tripolyphosphate ratio of 6:1 yielded optimum nanoparticles of size 187 ±â€¯58 nm, polydispersity index 0.24 ±â€¯0.01, zeta potential 36 ±â€¯6 mV, and encapsulation efficiency of 39 ±â€¯3%. Encapsulation efficiency was doubled to 80 ±â€¯1.5% by varying pH of the ionotropic solution components and by subsequent coating of the NPs with zein, increasing NP diameter to 377 ±â€¯47 nm, whilst retaining polydispersity index and zeta potential values. Selenomethionine-entrapped nanoparticles were not cytotoxic to intestinal and liver cell lines. Accelerated thermal stability studies indicated good stability of the nanoparticles under normal storage conditions (23 °C). In simulated gastrointestinal and intestinal fluid conditions, 60% cumulative release was obtained over 6 h.

Sodium caprate enables the blood pressure-lowering effect of Ile-Pro-Pro and Leu-Lys-Pro in spontaneously hypertensive rats by indirectly overcoming PepT1 inhibition.

The tripeptides, Ile-Pro-Pro (IPP) and Leu-Lys-Pro (LKP), inhibit angiotensin-converting enzyme (ACE) resulting in lowered blood pressure. Our hypothesis was that the medium chain fatty acid permeation enhancer, sodium caprate (C10), may prevent the decrease in permeability of the tripeptides when PepT1 is inhibited by glycyl-sarcosine (Gly-Sar), a situation that may occur in the presence of food hydrolysates. Using Caco-2 monolayers and isolated rat jejunal tissue, the apparent permeability coefficients (Papp) of [3H]-IPP and [3H]-LKP were assessed in the presence of Gly-Sar with and without C10. Gly-Sar decreased the Papp of both tripeptides across monolayers and isolated jejunal tissue, but C10 restored it. C10 likely increased the paracellular permeability of the tripeptides, as indicated by immunofluorescence changes in tight junction proteins in Caco-2 monolayers accompanied by a concentration-dependent decrease in transepithelial electrical resistance (TEER). [3H]-IPP and [3H]-LKP were orally-gavaged to normal rats with Gly-Sar, C10, or with a mixture. Plasma levels of both peptides were reduced by Gly-Sar to less than half that of the levels detected in its absence, but were restored when C10 was co-administered. In spontaneously hypertensive rats (SHRs), unlabelled IPP and LKP lowered blood pressure when delivered either by i.v. or oral routes. Oral gavage of Gly-Sar reduced the hypotensive action of peptides in SHRs, but the effect was restored in the presence of C10. In conclusion, there was a reduction in the hypotensive effects of IPP and LKP in SHRs when intestinal PepT1 was inhibited by Gly-Sar, but C10 may circumvent this by enhancing paracellular permeability.

Formulation, Characterization and Stability Assessment of a Food-Derived Tripeptide, Leucine-Lysine-Proline Loaded Chitosan Nanoparticles.

The chicken- or fish-derived tripeptide, leucine-lysine-proline (LKP), inhibits the angiotensin converting enzyme and may be used as an alternative treatment for prehypertension. However, it has low permeation across the small intestine. The formulation of LKP into a nanoparticle (NP) has the potential to address this issue. LKP-loaded NPs were produced using an ionotropic gelation technique, using chitosan (CL113). Following optimization of unloaded NPs, a mixture amount design was constructed using variable concentration of CL113 and tripolyphosphate at a fixed LKP concentration. Resultant particle sizes ranged from 120 to 271 nm, zeta potential values from 29 to 37 mV, and polydispersity values from 0.3 to 0.6. A ratio of 6:1 (CL113:TPP) produced the best encapsulation of approximately 65%. Accelerated studies of the loaded NPs indicated stability under normal storage conditions (room temperature). Cytotoxicity assessment showed no significant loss of cell viability and in vitro release studies indicated an initial burst followed by a slower and sustained release.

(1)H NMR spectroscopy and chemometrics evaluation of non-thermal processing of orange juice.

This study evaluated the effect of atmospheric cold plasma and ozone treatments on the key compounds (sugars, amino acids and short chain organic acids) in orange juice by NMR and chemometric analysis. The juice was directly and indirectly exposed to atmospheric cold plasma field at 70kV for different treatment time (15, 30, 45 and 60sec). For ozone processing different loads were evaluated. The Principal Component Analysis shown that the groups of compounds are affected differently depending on the processing. The ozone was the processing that more affected the aromatic compounds and atmospheric cold plasma processing affected more the aliphatic compounds. However, these variations did not result in significant changes in orange juice composition as a whole. Thus, NMR data and chemometrics were suitable to follow quality changes in orange juice processing by atmospheric cold plasma and ozone.

Acrylamide reduction in potato chips by selection of potato variety grown in Iran and processing conditions.

BACKGROUND: Acrylamide as a possible carcinogen is known to form in heated carbohydrate-rich food such as potato chips. In this study, the effect of three potato varieties (Agria, Sante and Savalan) and two blanching conditions (75 °C for 9 min and 83 °C for 2.5 min) on the concentration of precursors and acrylamide reduction in potato chips was investigated. RESULTS: Results revealed that potato variety and blanching time-temperature were important parameters for acrylamide formation in potato chips. Acrylamide content in Sante variety potatoes, which contained the highest amount of reducing sugars, was found to be the highest (8825 µg kg(-1)). However, Savalan, containing the highest asparagine concentration, showed the lowest amount of acrylamide due to its lower reducing sugar content. Blanching reduced acrylamide formation; it was more efficient at 75 °C for 9 min, with an average reduction of 74%. The effect of three frying temperatures (170, 180 and 190 °C) on acrylamide formation was also studied just for the Agria potato variety. Increasing frying temperature led to a significant increase in acrylamide formation. CONCLUSION: Potato variety and processing conditions were important parameters for acrylamide formation in potato chips. The combination of a suitable variety and appropriate processing conditions could considerably reduce acrylamide content.

PK/PD modelling of comb-shaped PEGylated salmon calcitonin conjugates of differing molecular weights.

Salmon calcitonin (sCT) was conjugated via cysteine-1 to novel comb-shaped end-functionalised (poly(PEG) methyl ether methacrylate) (sCT-P) polymers, to yield conjugates of total molecular weights (MW) inclusive of sCT: 6.5, 9.5, 23 and 40kDa. The conjugates were characterised by HPLC and their in vitro and in vivo bioactivity was measured by cAMP assay on human T47D cells and following intravenous (i.v.) injection to rats, respectively. Stability against endopeptidases, rat serum and liver homogenates was assessed. There were linear and exponential relationships between conjugate MW with potency and efficacy respectively, however the largest MW conjugate still retained 70% of E(max) and an EC(50) of 3.7nM. In vivo, while free sCT and the conjugates reduced serum [calcium] to a maximum of 15-30% over 240 min, the half-life (T(1/2)) was increased and the area under the curve (AUC) was extended in proportion to conjugate MW. Likewise, the polymer conferred protection on sCT against attack by trypsin, chymotrypsin, elastase, rat serum and liver homogenates, with the best protection afforded by sCT-P (40kDa). Mathematical modelling accurately predicted the MW relationships to in vitro efficacy, potency, in vivo PK and enzymatic stability. With a significant increase in T(1/2) for sCT, the 40kDa MW comb-shaped PEG conjugate of sCT may have potential as a long-acting injectable formulation.

Purification and properties of Amycolatopsis mediterranei DSM 43304 lipase and its potential in flavour ester synthesis.

An extracellular thermostable lipase from Amycolatopsis mediterranei DSM 43304 has been purified to homogeneity using ammonium sulphate precipitation followed by anion exchange chromatography and hydrophobic interaction chromatography. This protocol resulted in a 398-fold purification with 36% final recovery. The purified A. mediterranei DSM 43304 lipase (AML) has an apparent molecular mass of 33 kDa. The N-terminal sequence, AANPYERGPDPTTASIEATR, showed highest similarity to a lipase from Streptomyces exfoliatus. The values of K(m)(app) and V(max)(app) for p-nitrophenyl palmitate (p-NPP) at the optimal temperature (60°C) and pH (8.0) were 0.099±0.010 mM and 2.53±0.06 mmol/min mg, respectively. The purified AML displayed significant activity towards a range of short and long chain triglyceride substrates and p-nitrophenyl esters. Hydrolysis of glycerol ester bonds occurred non-specifically. The purified AML displayed significant stability in the presence of organic solvents (40%, v/v) and catalyzed the synthesis of the flavour ester isoamyl acetate in free and immobilized states.

Use of Fourier transform infrared spectroscopy and chemometric data analysis to evaluate damage and age in mushrooms (Agaricus bisporus) grown in Ireland.

The aim of this research was to investigate whether the chemical changes induced by mechanical damage and aging of mushrooms can be (a) detected in the midinfrared absorption region and (b) identified using chemometric data analysis. Mushrooms grown under controlled conditions were bruise-damaged by vibration to simulate damage during normal transportation. Damaged and nondamaged mushrooms were stored for up to 7 days postharvest. Principal component analysis of Fourier transform infrared (FTIR) spectra showed evidence that physical damage had an effect on the tissue structure and the aging process. Random forest classification models were used to predict damage in mushrooms producing models with error rates of 5.9 and 9.8% with specific wavenumbers identified as important variables for identifying damage, and partial least-squares (PLS) models were developed producing models with low levels of misclassification. Modeling postharvest age in mushrooms using random forests and PLS resulted in high error rates and misclassification; however, random forest models had the ability to correctly classify 82% of day zero samples, which may be a useful tool in discriminating between "fresh" and old mushrooms. This study highlights the usefulness of FTIR spectroscopy coupled with chemometric data analysis in particular for evaluating damage in mushrooms and with the possibility of developing a monitoring system for damaged mushrooms using the FTIR "fingerprint" region.

Postharvest hardness and color evolution of white button mushrooms (Agaricus bisporus).

UNLABELLED: The quality evaluation of mushrooms was studied by storing fresh white button mushrooms (Agaricus bisporus) for 6 to 8 d, at various controlled temperature conditions (3.5 to 15 degrees C) and measuring the instrumental textural hardness and color of the mushroom cap for different product batches. A nonlinear mixed effect Weibull model was used to describe mushroom cap texture and color kinetics during storage considering the batch variability into account. Storage temperature was found to play a significant role in controlling texture and color degradation. On lowering storage temperature (i) the extent of the final browning extent in the mushroom after storage was reduced and (ii) the rate textural hardness losses was slowed down. A linear dependence of the final browning index with temperature was found. An Arrhenius type relationship was found to exist between the temperature of storage and storage time with respect to textural hardness. The average batch energy of activation was calculated to be 207 +/- 42 kJ/mol in a temperature range of 3.5 to 20 degrees C. PRACTICAL APPLICATION: This article evaluates how temperature abuse affects mushroom texture and color, applying methods that allow for the consideration of the natural product variability that is inherent in mushrooms. Its results apply to mushroom producers, retail distribution, and supermarkets for effective storage management.

Prediction of polyphenol oxidase activity using visible near-infrared hyperspectral imaging on mushroom (Agaricus bisporus) caps.

Physical stress (i.e., bruising) during harvesting, handling, and transportation triggers enzymatic discoloration of mushrooms, a common and detrimental phenomenon largely mediated by polyphenol oxidase (PPO) enzymes. Hyperspectral imaging (HSI) is a nondestructive technique that combines imaging and spectroscopy to obtain information from a sample. The objective of this study was to assess the ability of HSI to predict the activity of PPO on mushroom caps. Hyperspectral images of mushrooms subjected to various damage treatments were taken, followed by enzyme extraction and PPO activity measurement. Principal component regression (PCR) models (each with three PCs) built on raw reflectance and multiple scatter-corrected (MSC) reflectance data were found to be the best modeling approach. Prediction maps showed that the MSC model allowed for compensation of spectral differences due to sample curvature and surface irregularities. Results reveal the possibility of developing a sensor that could rapidly identify mushrooms with a higher likelihood to develop enzymatic browning, hence aiding produce management decision makers in the industry.

Influence of cultivation conditions on the production of a thermostable extracellular lipase from Amycolatopsis mediterranei DSM 43304.

Among several lipase-producing actinomycete strains screened, Amycolatopsis mediterranei DSM 43304 was found to produce a thermostable, extracellular lipase. Culture conditions and nutrient source modification studies involving carbon sources, nitrogen sources, incubation temperature and medium pH were carried out. Lipase activity of 1.37 +/- 0.103 IU/ml of culture medium was obtained in 96 h at 28 degrees C and pH 7.5 using linseed oil and fructose as carbon sources and a combination of phytone peptone and yeast extract (5:1) as nitrogen sources. Under optimal culture conditions, the lipase activity was enhanced 12-fold with a twofold increase in lipase specific activity. The lipase showed maximum activity at 60 degrees C and pH 8.0. The enzyme was stable between pH 5.0 and 9.0 and temperatures up to 60 degrees C. Lipase activity was significantly enhanced by Fe(3+) and strongly inhibited by Hg(2+). Li(+), Mg(2+) and PMSF significantly reduced lipase activity, whereas other metal ions and effectors had no significant effect at 0.01 M concentration. A. mediterranei DSM 43304 lipase exhibited remarkable stability in the presence of a wide range of organic solvents at 25% (v/v) concentration for 24 h. These features render this novel lipase attractive for potential biotechnological applications in organic synthesis reactions.

Simultaneous modelling of the thermal degradation kinetics of pectin methylesterase in lettuce (Lactuca sativa L.) and carrot (Daucus carota L.) extracts: analysis of seasonal variation and tissue type.

The thermal degradation kinetics of pectin methylesterase (PME) from carrot and lettuce were studied. Fresh extracts were exposed to temperatures from 55 to 70 degrees C until the enzyme was inactivated. A model based on the presence of two forms of the enzyme, one active and one non-active, is proposed. The natural variability of the PME activity was taken into the model in the form of normally distributed random effects. The common model parameters obtained (cleavage constant (0.0395+/-0.0062 s(-1)), degradation constant (0.556+/-0.112 s(-1)), cleavage energy of activation (469+/-23 kJ mol(-1)) and degradation energy of activation (488+/-18 kJ mol(-1))) show that the PME degradation kinetics of the two vegetables can be explained with a single set of parameters.