Transfer kinetics of labeled aroma compounds from liquid media into coffee beans during simulated wet processing conditions.

The transfer kinetics of three labelled compounds (butanal, 2-phenyethanol, isoamyl acetate) was studied from a liquid medium into the coffee beans during simulated wet processing using four media (M) (M1: contained dehulled beans, M2: contained demucilaginated beans, M3: contained depulped beans, M4: contained depulped beans with yeast). Trials were carried out at 25 °C, under agitation and for five time periods (0, 6, 12, 24 and 48 h), and then the labelled volatiles were analyzed by SPME-GC-MS. The three labelled molecules were transferred into the coffee beans with different mass transfer rates; reaching at 12hrs in the M4, 0.2 ± 0.03, 11.2 ± 0.66 and 1.3 ± 0.04 µg/g of coffee respectively for butanal, 2-phenyethanol and isoamyl acetate. The parchment resistance significantly affected the mass transfer of the 2-phenylethanol. Butanal and isoamyl acetate underwent metabolic reactions, which decreased their amount in the coffee beans. Furthermore, an interaction between molecules and the yeast was observed and decreased significantly the butanal's transfer.

Influence of sodium chloride and pH during acidic marination on water retention and mechanical properties of turkey breast meat.

Turkey breast cubes underwent acidic marination in the presence of salt. The transfer of water, salt and acid was measured, and texture was assessed on the cooked meat. While significant mass gains were observed during marination, from 20 minutes of immersion onwards, only long durations produced an overall matter balance greater than that of non-marinated meat. From the first minutes of immersion, these transfers caused hardening, regardless of the presence of salt in the marinade. For longer durations, only in the absence of salt was significant tenderizing seen in comparison to the non-marinated control. This effect appears to be due on the one hand to passing the isoelectric pH of the meat during acidification, and on the other hand to setting up antagonistic mechanisms breaking down or reinforcing connective tissues by acid and salt respectively. The high degree of tenderization observed in a water-acid solution can be explained partly by dilution of the fiber load per section unit due to protein solubilization.

Evolution of pH during immersion of meat protein matrices in acidic marinades.

The pH value is a fundamental datum to be monitored during marination. A method is proposed for calculating the evolution of pH of turkey meat cubes during marination in an acetic acid solution. It is based on measurement of the buffering capacity by acidification using a strong acid. A calculation based on the dissociation equilibrium of acetic acid is used to estimate the mean pH reached, factoring in the acid content of the meat. For long marination times, the calculated pH is over-evaluated in relation to the experimental value. This can be explained by the significant loss of buffering substances during immersion. After 6h of immersion, the matrix's proton binding capacity may be reduced to just 20% of the initial value. Hence to improve the prediction of meat cut pH during marination, it is necessary to factor in the outgoing flow of buffering substances.

Decontamination of chicken skin surfaces inoculated with Listeria innocua, Salmonella enteritidis and Campylobacter jejuni by contact with a concentrated lactic acid solution.

1. The aim was to establish how poultry skin could be efficiently decontaminated without changing its organoleptic properties. 2. Chicken skins were surface inoculated with Listeria innocua and treated with different acid solutions (2 and 10% lactic acid for 1 and 30 min). Surviving bacteria were enumerated immediately after treatment and after 7 d storage at 4 degrees C. 3. Reductions of up to 2.6 log were reached immediately after treatment. The treatment effect persisted for 7 d storage, when the reduction exceeded 4.59 log for the strongest treatment. 4. Residual levels of lactic acid were not significantly higher than in untreated controls, except for the strongest treatment. A tasting panel found no significant difference between controls and samples. 5. After the initial results, an apparently optimal treatment (5% lactic acid for 1 min) was applied on chicken skins' surface inoculated with a mix of Listeria innocua, Salmonella enteritidis and Campylobacter jejuni. Treatment efficacy was assessed immediately after treatment and after 1, 4 and 7 d storage. 6. This treatment seems to be very promising from a food processing standpoint, being fast and allowing decimal reductions of 2.00 log for Listeria innocua and 2.38 log for Salmonella enteritidis after 7 d storage, neither significantly increasing skin lactic acid nor causing any organoleptic modifications to the product. The effect of the treatment is significant after one day storage for Listeria innocua and after 4 d storage for Salmonella enteritidis.

Soaking turkey meat in salt-glucose syrup solutions--an experimental study of mass transfers.

Turkey meat can be salted and dried in one step by soaking in a concentrated salt-glucose syrup solution at low temperature. Sugar impregnation is minimal; only low molecular weight sugars generally penetrate the product. Glucose uptake is very quick, suggesting the possible involvement of passive glucose transporters. The operational scope of this process, depending on the targeted end-product features, was determined for turkey meat on the basis of clearly characterized mass transport phenomena between the product and the soaking solution. With 2 cm thick meat fillets processed at 10 C it is thus possible to obtain salted-dried end-products containing 2 to 10% salt and 35 to 70% water, ranges that are compatible with a broad range of commercial cured products.

Characterization of traditional processing of pork meat into boucané.

Boucané is a traditional meat product from Réunion that is obtained by salting, drying and hot smoking pork belly. One-step unit operations give rise to a stable product with remarkable colour and flavour qualities. Smoking the product directly over embers, however, leads to benzo(a)pyrene contamination. Mass transfers (salt gain, water loss) stabilize the end product, which has a 28.5% water content and 5.6% salt content. Lipid oxidation and Maillard reactions are the main mechanisms involved in the boucané production process. The molecules derived from these two reactions are - along with smoke compounds - responsible for the flavour and colour of the end product.

Optimizing the traditional processing of beef into Kilishi.

Kilishi, a meat-based traditional product of Sahelian Africa, is a sun-dried, coated and grilled beef. The effect of moisture content of the dried meat before coating and sauce ingredients, on coating quality and product yield of kilishi were determined. Analysis of the losses after the coating and grilling stages highlighted the mechanisms that determine coating quality. To improve sauce adhesion to the dried meat, wheatflour was added to the traditional sauce (a mixture of groundnut paste, water, and spices). The amounts of water and wheat flour required to ensure that the sauce adhered to the meat well were also determined. This has optimized the kilishi processing to improve product yield.

Formulation of a cured meat product by the dewatering-impregnation soaking (DIS) process: Mass transfer study and assessment of product quality.

Venison muscle meats were simultaneously salted and dried by soaking in a mixed concentrated solution (salt/corn starch syrup) at a low temperature, a process known as dewatering and impregnation soaking (DIS). Cured products of suitable market quality (in terms of their salt and water content) were obtained with this process. The impregnation of standard curing additives (nitrites and polyphosphates) into the meat product was controlled by mixing these compounds in the concentrated solution. Also, beneficial effects of additives on the physicochemical, microbiological and organoleptic characteristics of the product are confirmed. The present study highlights the choice of DIS process and proposed optimal DIS conditions for formulating cured products.