2.5. Technological Characterization

The AAAC approved method 66–50 [16] was used to determine the cooking time. Twenty-five grams of pasta were put into a beaker containing 300 mL of boiling water (without salt addition). Every 30 s, some macaroni pieces were taken out and pressed between two glass plates. The optimal cooking time (OCT) corresponded to the disappearance of the white core [17].

Five grams of pasta sample were placed in a beaker containing 100 mL of tap water (ratio pasta; water of 1:20), which was placed in a thermostatic bath at 25 °C. After 5, 10, 15, 30, 60, 90 and 180 min of incubation, samples were removed from water, drained for 1 min, carefully blotted with tissue paper to remove superficial water, and weighed. The results were expressed as ((W1 − W0)/W0) × 100, where W1 is the weight of the hydrated sample and W0 is the weight of the dry sample [18].

Cooking loss was evaluated by determining the amount of solid losses into the cooking water [19]. Portions of 30 g of pasta were cooked in 300 mL of boiling tap water (ratio pasta:water of 1:10) without salt addition. Pasta samples were cooked for the OCT. After cooking, the volume of water was brought to the initial volume. Dry matter was determined on 25 mL of freeze-dried cooking water. The residue was weighed, reported as percentage of the dry material, and expressed as grams of matter loss/100 g of pasta.

The water absorption during cooking was evaluated by weighing pasta before and after cooking at OCT. It was calculated as ((W1 – W0)/W0) × 100, where W1 is the weight of cooked pasta and W0 is the weight of the uncooked samples.

Mechanical properties of pasta were analyzed using a texture analyzer, Texture analyzer FRTS-100N, (Imada, Toyohashi, Japan) equipped a 10 kg load cell and a cylinder probe FR-HA-50J. For the analysis, pasta samples were cooked until the OCT, rinsed with water at 25 °C and placed into a beaker (about 30 g), filled to about half volume. The following settings were used: test speed 1 mm/s, 30% deformation of the sample, and two compression cycles. Each measurement was performed in 3 replicates obtained in different batches and the parameters evaluated were hardness (expressed as the maximum force at first compression), cohesiveness (ratio of the areas of the second and the first compression peak), springiness (height of the product on the second compression divided by the height of the first peak), and chewiness (hardness × cohesiveness × springiness).

The CIELab color space coordinates L (lightness), a* (red-green chromaticity) and b* (yellow-blue chromaticity) of the samples were obtained by a Minolta CR-10 camera and a D65 illuminant. Color difference, ∆E*ab, was calculated as follows:

where ∆a, ∆b and ∆L are the differences for L, a, and b values between sample and reference (a white ceramic plate having L = 93.4, a = −1.8, and b = 4.4).