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Meat tenderness is one of the most important quality criteria when evaluating results of cooking conditions. Changes in tenderness and weight losses of heat-treated meat (semitendinosus muscle) for different time-temperacure Combinations were analyzed; the relationship between protein denaturation and textural changes was studied.Heat treatments of meat samples (I .5 cm in diameter, 2 cm long) were perjormed in a thermostatic bath in the 60-9OC range. Maximum heating times were 180 min. Meat hardness was determined by Warner-Bratzler measurements using an lnstron testing machine. Protein denaturation was followed by Differential Scanning Calorimetry (DSC) analyzing peaks for myosin (1 and Il), sarcoplasmatic proteins and collagen (11) and actin (1Il).Between 60 and 64C, hardness decreased with cooking time until reaching the lowest asymptotic values. This was related to protein denaturation of peak 1 and Il. Between 66 and 68C, hardness decreased at first but increased later due to actin denaturation; at the temperatures 81 and 90Cno modifications were observed and hardness remained at its higher values.The kinetic model proposed fit the experimental results satisfactorily. Activation energies of tenderizing and toughening processes are similar to those of protein denaturation of peak 11 and Ill. Weight losses due to cooking were also modelled increasing through the entire temperature range.

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The effects of ripening temperature, type of packaging film and storage period before packaging were related to the degree of proteolysis and the texture of Gouda cheese, so as to determine the optimum ripening conditions. Gouda cheeses from a local plant were subjected to different ripening conditions. A factorial design of 2 3 ϫ 5 was used, where the three factors selected in two levels were: (1) time of storage before packaging, 4 and 10 days, (2) ripening temperature, 10 and 20°C and (3) plastic film, BK1 and BK5 (Grace, Quilmes, Argentina). Ripening time was a fourth factor analyzed; sampling times were 15, 25, 35, 49 and 70 days after production. Cheeses traditionally ripened (without packaging) were also analyzed. Water content and pH were determined. Nonprotein nitrogen (soluble in 12% trichloracetic acid (TCA)) was quantified by the Kjeldhal method. Cheese texture was analyzed by compression and relaxation tests which were done by using an Instron Universal Testing Machine (Instron Corp., Canton, MA, USA). The pH and water content of cheeses which ripened at 20°C were lower than the corresponding ones ripened at 10°C. Only ripening time and temperature had a significant effect on water content, nonprotein nitrogen concentration and rheological parameters. Results show that texture properties of Gouda cheese ripened in plastic films with low gaseous permeability are similar to those of traditionally ripened Gouda. Texture development was accelerated by increasing the storage temperature.

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Reducing fat content of fried foods by application of coatings is an alternative solution to comply with both health concerns and consumer preferences. The objective of the present work was to analyse the effect of coating formulation on the quantity and composition of oil-uptake by potato strips and dough discs, and the quality of frying oil after several frying batches. The effect of coating composition showed that the most efficient formulations were 1% methylcellulose (MC) and 0.5% sorbitol for fried potatoes and 1% MC and 0.75% sorbitol for dough discs. The most effective coating formulations reduced oil uptake by 35-40%, depending on the product. The increase in water content was 6.3% and 25.7% for potato strips and dough discs, respectively. Although coatings were effective barriers to reduce oil uptake in fried products, they did not modify oil composition as detected by HPLC analysis. Oil stability of frying oils, evaluated by total polar compounds and acidity, was within the allowed limits established by the Argentine Food Code (acidity <0.6mg KOH/g oil).