ACTA ALIMENTARIA VOL. 4 (A QUARTERLY OF THE COMMITTEE ON FOOD SCIENCE OF THE HUNGARIAN ACADEMY OF SCIENCES, 1975)

1975 / 1. sz. - KOVÁCS, E.-VAS, K.-BENCZE-BŐCS, J.: Objective determination of the heat treatment requirement of cooked potatoes

2* 3 KOVÁCS et al.: HEAT TREATMENT REQUIREMENT OF POTATO COOKING 1.2. Cooking experiments 1.2.1. Preparation of raw material. Peeled potatoes were used in the experiments in two forms, (a) cut across the long axis of the tuber into discs of 15 mm thickness, with a diametre of 30—35 mm except for the variety Maryke which had an average diametre of 70—80 mm, and (b) cut into discs of 1.5 d: 0-2 mm, with a diametre of 26 mm. This diametre was secured by first producing potato cylindres by the use of a cork-borer of 26 mm diametre and then cutting these cylindres with a cucumber slicer. 1.2.2. Heat treatment. In all cases, a 1.5% NaCl brine was used as the heat transfer medium. The ratio of brine to potato was 2 to 1 in the case of the 15-mm discs and 10 to 1 with discs of 1.5 mm thickness. In this way, it could be achieved that, on introducing the potato slices into the brine of pre­determined temperature, the drop in the latter was very low (with 15-mm discs: 0.5—1.0 °C for less than 3 min in a brine of 95 °C) or nil (with 1.5-mm slices). Cooking temperatures applied were as follows: 75, 80, 85, 90 and 95 °C. Cooling to room temperature was done by decanting the brine. 1.3. Measurement of consistency Mechanical properties of potatoes were measured at room temperature with a Texturometer manufactured by the Zenken Co., Japan, under licence from General Foods Corp., USA. The conditions of measurement were as follows: — dentures bronze plunger, — articulator speed: 12 chews per minute, — recording paper speed: 750 min min-1, receiver for the electric signal operative in the range of 0—2.5 V (at 0.5 V), — "Attenuator 1" adjustment. Hardness of the 1.5-mm slices was measured by piling 4—5 discs on each other to reach an integrated thickness of 6.7—7.0 mm. Evaluation of texture measurements was carried out as described by KOVÁCS and VAS (1969). The height of the peak was taken as the measure for hardness. 1.4. Sensory tests To determine the "cooked state" of potatoes and to correlate sensory with instrumental evaluation, 15-mm discs were cooked at 95°C for varying periods, and tested by 5—10 tasters with the same lots of potatoes on two Acta Alimentaria 4,1975

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