Dados do Trabalho

Título

Effect of thermal treatment on phenolic compounds from seriguela (Spondias purpurea L.) pulp - a kinetic study

Introdução

Seriguela is an exotic fruit rich in phenolic compounds such as gallic acid, vanillic acid, ρ-coumaric acid, rutin and catechin. Thermal processing methods are often necessary to extend the shelf life of fruit-based products. The aim of this study was to evaluate the thermal stability of phenolic compounds and the antioxidant activity of seriguela pulp.

Material e Métodos

Seriguela pulp treated with a combination of different carbohydrases (a ternary mixture of Pectinex, Celluclast and Viscozyme), and non-treated pulp (control) were submitted to thermal processing using different temperatures (40, 50, 60 and 70°C) and incubation times (0, 15, 30, 45, 60, 90 and 120 min). After heat treatment, the samples were immediately frozen. The thermal effects on the content of total phenolic compounds (TPC) and antioxidant activity (ABTS, DPPH and FRAP) of the samples were determined. The kinetic parameters D-value (decimal reduction time defined as the time needed to reduce the initial phenolic content by 90%) and t½ (time needed for the phenolic content to reduce by 50%) were calculated.

Resultados e Discussão

The content of total phenolic compounds in the control pulp showed greater thermal resistance compared to the enzymatically treated pulp, with D-values and t½ values ranging from 822 to 255 min and 247 to 77 min, respectively, at temperatures between 40 and 70°C. On the other hand, for antioxidant activity, the enzymatically treated pulp showed greater stability compared to control, with t½ values ranging from 533.19 to 144.41, 433.22 to 216.61 and 192.54 to 115.52 for ABTS, DPPH and FRAP, respectively.

Conclusão

In the control run, most of the compounds are complexed with macronutrients such as carbohydrates and proteins, which may make them more resistant to the temperatures studied compared to the hydrolyzed pulp. Although the TPC retention was lower for the hydrolyzed pulp, it is important to highlight that not only the quantity, but the profile of phenolics remaining in the sample after heat treatment, influence the antioxidant profile. In this case, it is possible to infer that in the hydrolyzed pulp, although the TPC was lower, phenolics with greater antioxidant potential also showed greater thermal resistance.