Volatile compounds in dry-cured Serrano ham subjected to high pressure processing. Effect of the packaging material

From flours to cakes: Reactivity potential of pulse ingredients to generate volatile compounds impacting the quality of processed foods

This study investigated the impact of substituting wheat with pulse flours (lentil, chickpea, lupin, green and yellow pea) on reactivity during different steps of sponge cake development. Pulses exhibited a greater ability to generate volatiles with probable odor activity. Batter beating initiated lipid oxidation which depended on lipoxygenase activity and the fatty acid profile of the flours. Among the pulses, pea batters were richest in oxidation markers whereas lupin was least reactive, probably due to thermal pre-treatment. Baking triggered caramelization and Maillard reactions, notably with the pulse products which were particularly enriched in pyrazines and furanic compounds. Principle component analysis revealed that pea cakes were associated with oxidation markers that typically possess green-beany flavors, while Maillard markers known to impart nutty, roasted notes were assigned to lentil and chickpea cakes. These findings highlight the importance of ingredient type and its pre-processing in the development of quality-related markers for gluten-free products.

The efficacy and safety of high-pressure processing of food

High-pressure processing (HPP) is a non-thermal treatment in which, for microbial inactivation, foods are subjected to isostatic pressures (P) of 400-600 MPa with common holding times (t) from 1.5 to 6 min. The main factors that influence the efficacy (log10 reduction of vegetative microorganisms) of HPP when applied to foodstuffs are intrinsic (e.g. water activity and pH), extrinsic (P and t) and microorganism-related (type, taxonomic unit, strain and physiological state). It was concluded that HPP of food will not present any additional microbial or chemical food safety concerns when compared to other routinely applied treatments (e.g. pasteurisation). Pathogen reductions in milk/colostrum caused by the current HPP conditions applied by the industry are lower than those achieved by the legal requirements for thermal pasteurisation. However, HPP minimum requirements (P/t combinations) could be identified to achieve specific log10 reductions of relevant hazards based on performance criteria (PC) proposed by international standard agencies (5-8 log10 reductions). The most stringent HPP conditions used industrially (600 MPa, 6 min) would achieve the above-mentioned PC, except for Staphylococcus aureus. Alkaline phosphatase (ALP), the endogenous milk enzyme that is widely used to verify adequate thermal pasteurisation of cows' milk, is relatively pressure resistant and its use would be limited to that of an overprocessing indicator. Current data are not robust enough to support the proposal of an appropriate indicator to verify the efficacy of HPP under the current HPP conditions applied by the industry. Minimum HPP requirements to reduce Listeria monocytogenes levels by specific log10 reductions could be identified when HPP is applied to ready-to-eat (RTE) cooked meat products, but not for other types of RTE foods. These identified minimum requirements would result in the inactivation of other relevant pathogens (Salmonella and Escherichia coli) in these RTE foods to a similar or higher extent.

Volatile compounds in high-pressure-treated dry-cured ham: A review

The use of high pressure processing (HPP) for the treatment of dry-cured ham and other meat products has considerably increased worldwide. Its well-documented lethal effect on pathogenic and spoilage bacteria ensures the microbial safety of dry-cured ham and extends its shelf life. However, the effects of HPP on the volatile compounds, odor and aroma of dry-cured ham are less known. In the present review, the effects of HPP on the enzymes and microorganisms responsible for the generation of volatile compounds in dry-cured ham and the changes in the levels of the main groups of volatile compounds resulting from different HPP treatments are discussed. Particular attention is devoted to the fate of odor-active compounds after HPP treatments and throughout further commercial storage. The use of efficient sensory techniques yielding odor and aroma outputs closer to those perceived by consumers is encouraged. Needs for future research on the volatile compounds, odor and aroma of HPP-treated dry-cured ham are highlighted.

Effect of high pressure processing on migration characteristics of polypropylene used in food contact materials

The migration of small molecular mass organic compounds from polypropylene (PP) copolymer films into food simulants during and after high pressure processing (HPP) was studied. An overlapping temperature profile was developed to isolate the pressure effect of HPP (700 MPa, 71°C, 5 min) from equivalent thermal processing (TP) at atmospheric pressure (0.1 MPa). Chloroform, toluene, methyl salicylate, and phenylcyclohexane were chosen as surrogate compounds, and were spiked into test polymer films at concentrations of 762-1152 mg kg^-1 by a solvent soaking technique. Migration (w/w) of surrogate compounds from loaded PP films into Miglyol 812 (a medium-chain triglyceride mixture) and 10% ethanol was quantified by headspace GC/MS during HPP and TP, and subsequent storage at 25°C for up to 10 days. HPP significantly delayed migration of the surrogates from PP into both food simulants relative to TP. The average migrations into Miglyol after TP and HPP were 92.2-109% and 16-60.6%, respectively. Diffusion coefficients estimated by migration modelling showed a reduction of more than two orders of magnitude for all surrogate compounds under high pressure at 700 MPa (AP' = 8.0) relative to equivalent TP at 0.1 MPa (AP' = 13.1). The relative T_g increase of PP copolymer under compression at 700 MPa was estimated as T_g+94°C. For 10% ethanol, average migrations after TP and HPP were 9.3-50.9% and 8.6-22.8%, respectively. During extended storage, migration into both simulants from HPP-treated samples was initially slower than that from untreated or TP-treated films. However, after 8-24 hours of storage, the differences in percent migration of selected surrogates were not significant (p > .05) among the treated PP films. Therefore, the physical changes of PP films that occur during HPP appear to be reversible with a return to their original dimensions and diffusion properties after decompression.

Multivariate analysis approach for assessing coated dry-cured ham flavor quality during long-term storage

This study aimed to investigate the effect of coatings on the quality of ripened dry-cured hams during long-term storage, especially the profile of volatile compounds. The coatings were made up of 33% palm oil, 16.5% water, 39.7% cassava starch, 6.8% corn starch, 1.6% mono- and diglycerides of fatty acids, 0.6% tert-butylhydroquinone (TBHQ), and 1.8% sodium carbonate. The results showed that the moisture content of the coated ham (48.93-49.59%) was higher than that of the noncoated ham (44.37%). The average peroxide value (POV) and b* value were lower in the coated hams than in the noncoated hams (5.52 and 8.99 meq/kg, respectively), and the sensory attributes of the coated hams had better overall acceptability scores. The changes in the contents of 39 volatile flavor compounds were evaluated through a multivariate statistical analysis, revealing that 20 identified compounds could be related to the decrease in fat pungent aroma, and most belonged to the long-chain benzene and carboxylic acid family. Meanwhile, 2-nonanone, nonanal, amyl alcohol, and 2-heptanone indicated that they could be used as markers to distinguish between the coated and noncoated groups.

Effect of high-pressure processing and chemical composition on lipid oxidation, aminopeptidase activity and free amino acids of Serrano dry-cured ham

Lipid oxidation and proteolysis are essential processes in Serrano dry-cured ham quality. The influence of high pressure processing (HPP) at 600 MPa for 6 min on lipid oxidation, aminopeptidase (AP) activities and free amino acids (FAA) in ripened Serrano hams of different chemical composition after 5 months at 4 °C were studied. HPP increased lipid peroxidation indexes. Composition influenced both indexes, with higher levels in hams of medium or high intramuscular fat (IMF) content and in hams of low or medium salt content or salt-in-lean ratio. HPP lowered AP activities by more than 50%. Composition also affected AP activities, with lower levels in hams of low a_w, high IMF content, low salt content or low salt-in-lean ratio. At the end of refrigerated storage, HPP only affected Arg and Tyr levels. Many of the individual FAA reached higher levels in hams of low a_w, medium or high IMF content, low or medium salt content, or low or medium salt-in-lean ratio.

Effect of chemical composition and high pressure processing on the volatile fraction of Serrano dry-cured ham

The volatile fraction of 30 Serrano dry-cured hams with different salt and intramuscular fat contents was investigated. In addition, the effect of high pressure processing (HPP) at 600 MPa for 6 min at 21°C on the volatile compounds of those hams was studied. One hundred volatile compounds were identified and their levels subjected to analysis of variance with ham chemical composition (aw, salt content, intramuscular fat content and salt in lean ratio) and HPP treatment as main effects. Chemical composition mainly affected the relative abundance of acids, alcohols, branched-chain aldehydes, ketones, benzene compounds, sulfur compounds and some miscellaneous compounds. Salt content and fat content influenced a greater number of volatile compounds than aw. High pressure processing had a significant effect on only 8 volatile compounds, with higher levels of methanethiol and sulfur dioxide in HPP-treated samples and higher levels of ethyl acetate, ethyl butanoate, ethyl 2-methylbutanoate, ethyl 3-methylbutanoate, dimethyl disulfide and dimethyl trisulfide in control untreated samples.

Volatile compounds in Spanish dry-fermented sausage 'salchichón' subjected to high pressure processing. Effect of the packaging material

The effect of high pressure treatment (400MPa, 10min at 12°C) on the volatile profile of Spanish dry-fermented sausage 'salchichón', packaged with or without aluminium foil in a multilayer polymeric bag, was investigated. The analysis of the volatile fraction was carried out by dynamic headspace extraction coupled to gas chromatography-mass spectrometry. Pressure-treated samples showed significantly higher levels of alcohols, aldehydes and alkanes and lower levels of two methylketones as compared with control samples. An intense migration was observed of compounds from the plastic material into the product, mainly linear and branched-chain alkanes, alkenes and benzene compounds. Most of these migrating compounds were significantly more abundant in pressurized samples than in untreated samples.