Estabilidade dos componentes funcionais de geléia de yacon, goiaba e acerola, sem adição de açúcares

Abstract

The objective of this work was to evaluate stability of the functional components of a mixed yacon, guava and West Indian cherry jam with no added sugar, during a 180 day storage period at room temperature. The jam formulation was defined as 70% of the mixed pulps and 30% additives. The pulp mixture was previously heated, the other elements of the formulation added, and the mixture concentrated to 35 °Brix and subsequently hot filled, inverted, cooled and stored. Soon after processing (zero time), the jam was evaluated for: moisture, total solids, soluble solids, acidity, pH, Aw, total and reducing sugars, fructooligosaccharides (FOS), ascorbic acid and lycopene, plus the sensory quality according to purchase intention and microbiological quality according to commercial sterility. The final product was stored at room temperature and analyzed every 30 days for its FOS, ascorbic acid and lycopene contents, and every 90 days for commercial sterility. The results were evaluated statistically by ANOVA and differences between the means detected by the Tukey test. According to the sensory test, 70% of the panelists would possibly or certainly purchase the jam. Microbiologically, the final product remained stable throughout the storage period. After processing, the final products contained 0.52% FOS and 143 mg.100 g–1 of ascorbic acid, representing losses of 23.5 and 32.7%, respectively, as compared to the expected initial contents based on the pulp proportions used in the jam formulation. The losses were due to the processing conditions of temperature and acidity. On the other hand, the lycopene content increased 7.4% during processing. During storage the products maintained their lycopene and FOS contents, but showed 42.7% losses of ascorbic acid in relation to the initial value (zero time). It was thus concluded that the stability of the functional components was compromised by the heat processing and by the 180 days of storage at room temperature with exposure to light.