Avaliação da cor e da atividade antioxidante da polpa e extrato de mirtilo (Vaccinium myrtillus) em pó

• Autor(a) principal: Rocha, Fernanda Izabel Garcia da
• Data de Publicação: 2009
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/2865
• topic: Mirtilo; Extrato; Polpa; Caracterização; Blueberry; Extract; Pulp; Characterization; CNPQ::CIENCIAS AGRARIAS::CIENCIA E TECNOLOGIA DE ALIMENTOS::CIENCIA DE ALIMENTOS

Blueberry (Vaccinium myrtlillus) has drawn the attention of producers and consumers in recent years due to its nutritional quality and health benefits. It is a rich source of natural pigments, especially anthocyanins, and shows high added value due to the association as a functional food. This study aimed tocharacterize and evaluate the pulp and extract of blueberry from the variety Bluegem produced in the Southeastern region of the country, as well as to evaluate drying methods on the physical and chemical properties and bioactive compounds in the powders obtained. Right after the drying treatments were applied, it was determined the centesimal composition of pulp and peel, and the following physical and chemical analysis were conducted independently for pulp and extract: SST, ATT, pH, reducing and total sugars, color parameters (L*, a*, b*, h* and C*), anthocyanins by spectrophotometry and HPLC, phenolic compounds and antioxidant activity by DPPH. The SST content was similar for pulp and extract, about 11.40 ° Brix; the ATT in the pulp expressed as citric acid was 0.42; the pH was 3.30 in the pulp and 3.27 in the extract; the total sugar content in the pulp was 6.44 g/100 mL and reducing sugar was 0.51 g/100 mL. The concentration of polyphenols was 317.60 gand 2007 mgAGE/100; total anthocyanins was 58.95 and 1182 mg/100 g; antioxidant activity was 32.50 and 42.88%, for pulp and extract respectively. Blueberry proved to be rich in phenolic compounds and anthocyanins, and and to have a relative antioxidant activity. An alternative to the preservation of the blueberry is its dehydration by the atomization process (atomização) or by freeze drying, which allow obtaining dehydrated blueberry pulp and extract with high content of bioactive compounds. In the second phase, formulations of blueberry pulp and extract in powder were prepared according to the addition of 20% maltodextrin DE 10, and dried by two drying methods (atomização and lyophilization). The following evaluations were made: anthocyanins by spectrophotometry and HPLC,polyphenols, antioxidant activity by DPPH, total and reducing sugars, moisture, water activity (Aa), and colorimetry of h* (hue) and C* (saturation). The powder formulation with higher content of anthocyanins andphenols was obtained from the extract when the operations were performed on lyophilizer, with 2938.94 mg/100 g of anthocyanins and 7680 mgAGE/100g of polyphenols. The percentage of antioxidant activity by DPPH of the extract was higher when the drying was performed in a atomização, with 74.90% of sequestrant capacity. Saturation differed between drying methods, being 7.74 when the extract was dried by lyophilization, and 30.51 in the spray-drying. This difference results in higher intensity of red for the atomized extract; for the values of h*, there was no difference between the drying methods.