Effect of high pressure processing on sugar-snap cookie dough and cookie quality

BORNEO, RAFAEL; AGUIRRE, ALICIA; KARWE, M.

Córdoba

Congreso; V Congreso Internacional Ciencia y Tecnología de los Alimentos; 2014

Ministerio Ciencia y Tecnología Córdoba

A variety of new non-conventional methods for food preservation, like high pressure processing, have gained considerable acceptance by consumers due to the fact that they seem less harsh than conventional methods and because they are free of chemical additives. High pressure processing (HPP) is based on the use of high hydrostatic pressure (generally within the range of 100 to 1000 MPa) to destroy unwanted pathogen and spoilage microorganisms and to inactivate enzymes that may cause undesirable changes. Microbial, physical and structural changes in high pressured sugar-snap cookie dough were studied as a function of pressure level (MPa) and holding time (min). Briefly, dough samples were prepared as follows: margarine (180 g) and granulated sugar (288 g) were creamed for 3 min using a bench top mixer. Deionized cold water (48 g) was added and mixed for 2 min. Flour (400 g) and sodium bicarbonate (10 g) were added, followed by mixing for 2 min. Dough was divided in 150 g portions, gently hand rounded and thermosealed in polyethylene bags (removing as much air as possible from bags). Packed dough was placed into the HPP (10 L) vessel (Elmhurst, Inc., Albany, NY, U.S.A), filled with water, and then subjected to different pressures (100 MPa or 200 MPa) for two hold times (2 min or 4 min). One sample was subjected to 400 MPa for 15 min. Temperature never increased above 30 oC during HPP. Control dough without HPP treatment was used as reference. Cookies were cut with a metal cutter and baked for 14 min at 180 oC. Cookies were made three times (on three different days) using same procedure and equipment. The effect of HPP on the dough was investigated by determining the changes in microbial counts (total aerobic mesophilic bacteria, mould and yeasts), color and mechanical texture (hardness and adhesiveness). Cookies were analyzed for texture (snap test), color, and technological parameters (maximum diameter during baking, thickness, spread factor, etc). HPP reduced the native microbial population of cookie dough from 106 (aerobic mesophilic bacteria) and 104 (yeast and moulds) colony forming units (CFU)/g to levels of 10 CFU/g. The lower pressure and time (100 MPa -1 min) was enough to achieve such reductions. HPP treated dough had a brownish color (lower L values). Cookies baked with HPP treated dough were darker (lower L values) and had reduced hardness (snap test). Differential scanning calorimetry analyses showed that treatment with high pressure did not affect starch gelatinization (similar values of onset, peak, and enthalpy change). Scanning electron micrographs confirmed that starch modification did not occur at the pressure-time levels used in this study. Cookies made with HPP treated dough were flatter (higher values of diameter), and lower values of cookie height, which implies that HPP influences the rheological behavior of dough during baking.