Functional changes induced by extrusion during cocoa alkalization.

Polyphenols, a group of secondary metabolites, have well-known relevant effects on human health. During traditional alkalization, this content dramatically lowers. We aimed to evaluate an alternative alkalization method based on extrusion on cocoa functional characteristics. The results showed that the antioxidant capacity and total phenolic values increased as alkali concentration and temperature did, and these values doubled under less extreme conditions. Comparing the functional properties between extruded and traditionally produced powders revealed that catechin, epicatechin and dimers B1 and B2 contents were 43%, 33%, 54% and 34% lower in the extruded samples, respectively. However, this reduction was partially balanced by increased clovamide content up to 50%. Thus the total phenol content and antioxidant capacity of the extruded samples were statistically above those of the commercial one. Hence extrusion alkalization should be considered a new processing alternative to avoid markedly reducing functional properties.

Effect of partial sodium replacement on physicochemical parameters of smoked sea bass during storage.

The objective of this work was to study the effect of partial sodium replacement by potassium and packaging conditions on the physicochemical properties of smoked sea bass during cold storage. Sea bass fillets were salted with 100% NaCl (Na samples) or with 50% NaCl-50% KCl (Na:K samples), smoked, packaged under three different conditions (air, vacuum and modified atmosphere) and stored at 4 °C for 42 days. Physicochemical parameters, color and texture were periodically determined in the raw material and in smoked samples during cold storage. The smoking process led to a reduction in moisture, pH and a(w) values, and an increase in water holding capacity, ash and mineral contents. Smoked fish exhibited significant differences in color and texture as compared to fresh fish. The type of packaging had an effect on the pH, water holding capacity and texture. Samples in air exhibited the highest pH values and water holding capacity in these samples gradually decreased during storage. Textural parameters decreased during storage in samples packaged in vacuum and modified atmosphere. The pH of Na samples was initially higher than in Na:K samples, and this difference remained over the rest of the study. The type of salt did not affect the texture or other physicochemical parameters.