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The effect of thermal processing on the in vitro digestibility of pork proteins was studied. Raw samples were considered the control group, while the thermal treatments included 58, 80, 98 and 160 °C for 72 min, 118 °C for 8 min and 58 °C for 17 h, resembling a range of different cooking procedures. Samples were subsequently subjected to pepsin digestion at pH 3.00 in the gastric phase followed by trypsin and α-chymotrypsin at pH 8.00 in the intestinal phase. Pork cooked at 58 °C for 72 min had a significantly higher pepsin digestibility rate than meat cooked at 80 °C or 160 °C. The trend was similar in the intestinal phase, with samples cooked at 58 °C for 72 min having enhanced digestion rate over other treatments after 120 min of digestion. A PLS model pointed out to an inverse relationship between in vitro proteolysis rate and variables like Maillard reaction compounds or protein structural changes., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

The aim of the study was to characterize Maillard reactions in meat under different cooking treatments. Considered temperature-time combinations included raw samples (control), 58, 80, 98 and 160 °C for 72 min, 118 °C for 8 min and 58 °C for 17 h. Furosine, a marker for heat treatment, was detected in all groups with roasting having a 4-fold increase over the control. Sous-vide treatment at 80 °C, boiling and autoclaving also contribute to a significant increase in furosine. N ɛ -carboxymethyllysine, an indicator for advanced glycation end products, showed negligible amount in control, but increased with cooking temperature, with oven samples showing the highest values. A similar increasing trend was observed in lanthionine, covalently bonded protein crosslinks, which arises due to severe thermal regimes. Simultaneously, glycation and deamidation formation were tracked in meat proteins through peptidomics to highlight residue level changes that might affect nutrient value in processed muscle based foods., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

This study aimed to address the proteolytic phenomena taking place in pork loins during prolonged storage at superchilling (SC) temperature. Loins were stored at either chilling (CH) conditions (2-4 °C) for 4 weeks or at SC temperature (around -1 °C) for 12 weeks. Storage at SC temperatures slowed down the rate of proteolysis in pork loins, so that final levels of most indicators for proteolysis, including after 12 weeks of SC storage were similar to those after 4 weeks at CH conditions. Consequently, the texture of SC pork under extended storage was not so different to that of CH pork. However, total amino acid content peaked by the end of SC storage, pointing out to a potential ongoing exopeptidase activity. Overall, proteolysis seemed to be slowed down in pork at SC conditions, with similar levels for most indicators after 12 weeks of SC storage or 4 weeks at CH conditions., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The impact of thermal processing on meat proteins oxidation was investigated. Cooking treatments included 58 °C for either 72 min or 17 h (mimicking low temperature-long time sous vide cooking), 80, 98 and 160 °C for 72 min (mimicking common cooked meat products, stewing and roasting, respectively) and 118 °C for 8 min (autoclaving). Tryptophan degradation, fluorescent oxidation products, free thiol content and α-aminoadipic and γ-glutamic semialdehydes were tracked. For all of them, there was a consistent trend to increased levels of oxidative damage with higher cooking temperatures and longer cooking times, although the extent varied from one indicator to another. Through proteomics, peptide oxidative modifications like carbonylation, malonaldehyde adducts and hydroxykynurenin (tryptophan oxidation products) were also detected at residue level. Our findings indicate that protein oxidation is dependent upon the heat treatment, which point out to a different effect on the nutritional quality of proteins in meat products., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Structural modifications of pork proteins under an assortment of industrial heat treatments were studied. With raw as control, assorted heat treatments involved were 58, 80, 98 and 160°C for 72min, 118°C for 8min and 58°C for 17h, resembling most common processing procedures. Protein denaturation, surface protein hydrophobicity state and protein aggregation behaviour were investigated. Modifications and molecular chemistry in protein structures were tracked by Fourier Transform Infrared Spectroscopy in order to extract relative proportions of β-sheet, α-helix and residual conformations. In comparison to uncooked samples, cooked ones showed more than two-fold increase in hydrophobicity and larger particles. Thermograms from differential scanning calorimetry showed endothermic transitions (positive enthalpy) indicating a different pattern of protein denaturation as a result of varied cooking temperatures and cooking times. Deconvolution and curve fitting procedures (R 2 =0.99) provided information on rise of the β-sheet to α-helix ratio that further confirmed aggregation with thermal rise and longer cooking time., (Copyright © 2017 Elsevier Ltd. All rights reserved.)