Poliana Deyse Gurak

Storage At Low Temperature Differentially Affects The Colour And Carotenoid Composition Of Two Cultivars Of Banana

Different storage conditions can induce changes in the colour and carotenoid profiles and levels in some fruits. The goal of this work was to evaluate the influence of low temperature storage on the colour and carotenoid synthesis in two banana cultivars: Prata and Nanicão. For this purpose, the carotenoids from the banana pulp were determined by HPLC-DAD-MS/MS, and the colour of the banana skin was determined by a colorimeter method. Ten carotenoids were identified, of which the major carotenoids were all-trans-lutein, all-trans-α-carotene and all-trans-β-carotene in both cultivars. The effect of the low temperatures was subjected to linear regression analysis. In cv. Prata, all-trans-α-carotene and all-trans-β-carotene were significantly affected by low temperature (p<0.01), with negative estimated values (β coefficients) indicating that during cold storage conditions, the concentrations of these carotenoids tended to decrease. In cv. Nanicão, no carotenoid was significantly affected by cold storage (p>0.05). The accumulation of carotenoids in this group may be because the metabolic pathways using these carotenoids were affected by storage at low temperatures. The colour of the fruits was not negatively affected by the low temperatures (p>0.05).

Changes in antioxidant capacity and colour associated with the formation of β-carotene epoxides and oxidative cleavage derivatives

In this study HPLC-DAD-MS/MS was applied for the identification of compounds derived from (all-E)-β-carotene following epoxidation and oxidative cleavage. The consequences on the CIELAB colour parameters and antioxidant capacity (AC) were also evaluated. Five apocarotenoids, three secocarotenoids, seven Z isomers and two epoxides were detected as a result of the oxidative cleavage. Four epoxides and three Z isomers were detected as a consequence of the epoxidation reaction. Some compounds were detected for the first time as a result of oxidation reactions. Both treatments led to a marked decrease in b(∗) and Cab(∗) values, indicating that these colour parameters can be used for the rapid assessment of β-carotene oxidation. The oxidative cleavage of β-carotene resulted in increased capacity to both scavenge ABTS(+) and quench singlet oxygen. These results suggest that the study of the AC of these oxidative derivatives and their possible usefulness as food ingredients deserves further attention.

Production of grape juice powder obtained by freeze-drying after concentration by reverse osmosis

This study aimed to evaluate the freeze-drying proc ess for obtaining grape juice powder by reverse osm osis using 50% grape juice pre-concentrated (28.5 °Brix) and 5 0% hydrocolloids (37.5% maltodextrin and 12.5% arab ic gum). The morphology of the glassy food showed the absence of crystalline structure, which was the amo rphous wall that protected the contents of the powder. The samples were stored in clear and dark containers a t room temperature, evaluated for their physical (X-ray di ffraction) for 65 days and chemical (polyphenol con tent) stability for 120 days. During the storage time in plastic ve ssels, samples remained physically stable (amorphou s) and the phenolic concentration was constant, indicating the potentiality of this technique to obtain a stable product with a high concentration of phenolic compounds. Therefore , the freeze-drying process promoted the encapsulat ion of concentrated grape juice increasing its stability a nd shelf life, as well as proving to be an applicab le process to food industry.

Jaboticaba (Myrciaria jaboticaba) juice concentration by forward osmosis

ABSTRACT The concentration of jaboticaba juice by forward osmosis (FO) was evaluated. The statistical analysis showed that brine concentration and flow rate presented significant effect (p < 0.05) on water permeate flux, and only the brine concentration affected (p < 0.05) the salt transport. It was found that FO preserved the anthocyanin content and its antioxidant properties, although transport of sodium was observed in the reconstituted juice when it was concentrated by FO, reaching values of 12.9 mg of sodium equivalent per litre of juice. Thus, results indicate that FO is an interesting alternative to be used as a pre-treatment for concentration of liquid foods.

ELABORAÇÃO DE VINHO EM CULTURA MISTA DE LEVEDURAS NÃO-SACCHAROMYCES ISOLADAS DE JACA (Arthocarpus heterophyllus LAM) E Saccharomyces cerevisiae: AVALIAÇÕES QUÍMICA E SENSORIAL

Duas linhagens de leveduras nao-Saccharomyces provenientes da microbiota da jaca – Pichia pijperi e Candida valida – foram inoculadas em associacao com a linhagem de Saccharomyces cerevisiae em quatro diferentes processos de vinificacao. A partir das analises quimicas realizadas concluiu-se que a inoculacao dessas leveduras nao interferiu no processo de vinificacao. Uma equipe de provadores treinados avaliou sensorialmente os vinhos atraves de Analise Descritiva Quantitativa e os resultados analisados por Analise de Componentes Principais e Analise de Variância. O vinho inoculado com a linhagem de levedura Pichia pijperi apresentou atributos como odor indesejado e gosto indesejado, enquanto a linhagem Candida valida conferiu ao vinho atributos de aroma intensidade de aroma e intensidade de aroma frutado. Os resultados apontam o potencial de aplicacao de leveduras provenientes da microbiota da jaca como culturas em vinificacao.

PRODUÇÃO E ACEITABILIDADE DE FERMENTADO DE LARANJA NO ALTO URUGUAI CATARINENSE

Este trabalho teve como objetivo a elaboracao de fermentados de laranja a partir de frutas excedentes de producao. O suco de laranja foi chaptalizado a 22 % de solidos soluveis totais. A levedura Saccharomyces cerevisiae foi inoculada ao mosto e a fermentacao foi conduzida em condicoes de temperatura e pressao ambientais. Apos fermentacao, a clarificacao foi realizada com terra diatomacea. O fermentado de laranja foi engarrafado, pasteurizado e conservado a 5 ° C. Analises fisico-quimicas e sensoriais foram realizadas no produto final. Os fermentados produzidos apresentaram alto rendimento, baixo custo e caracteristicas organolepticas proprias para o consumo. Alem disto, a analise sensorial apresentou o indice de aceitabilidade entre 47 a 62 %, sendo uma alternativa viavel para a pequena agroindustria