Avaliação do teor de compostos fenólicos totais, capacidade antioxidante e análise sensorial de geleia mista de uva Isabel com carnaúba.

Abstract

The carnauba and the Isabel grape are fruits that have a high composition of nutrients, presenting mainly high content of vitamin C, anthocyanins and high antioxidant power. An alternative to increase the useful life of these fruits is to use them in the form of jelly, but the thermal processing of fruits leads to the loss of many nutrients, thus reducing their nutritional value. This fact happens mainly in foods that have phenolic compounds, because they are highly sensitive to heat. The research aimed to elaborate different jelly formulations using Isabel and carnauba grapes, to evaluate the total phenolic compounds (flavonoids and anthocyanins) and antioxidant activity of the products, as well as to evaluate their physical, chemical and sensorial characteristics. The research was carried out with carnauba from the city of Aparecida - Paraíba. The Isabel grape was purchased in the city of Cuité - PB. The study was developed at the Federal University of Campina Grande, Campus Cuité in the Laboratory of Food Technology, Laboratory of Bromatology and in the Laboratory of Sensory Analysis of Food. Physical analysis of fruits, elaboration of three jelly formulations: carnauba jelly, grape jelly and carnauba jelly with grape, characterized as extra jelly. For the physical-chemical analysis of the jelly, titratable total acidity, pH, determination of total anthocyanins, determination of total phenolic content, antioxidant activity - Radial method (ABTS) and iron reducing capacity (FRAP) were evaluated. Sensory analysis was performed, with 60 untrained testers and all participants signed the Informed Consent term. For the statistical treatment of the data, the Sigma Stat program was used, using analysis of variance (ANOVA) and the Tukey test of means with a security level of 95%. Carnauba and grape fruits with rounded shape and yield of 42.33% and 100%, respectively, were verified in the physical analysis. As for the physical-chemical characteristics of the jelly, it was verified that the mixed jelly had higher values for moisture, Ph, acidity, when compared to the others. The ash content in carnauba jelly was higher than the other jellies. There was no significant difference for soluble solids. For total phenolic content, total flavonoids the value found in mixed jelly was superior to the others and for anthocyanins the mixed jelly had a value higher than carnauba jelly. For the antioxidant activity, the mixed jelly did not differ from that of grape presenting higher antioxidant action (FRAP) when compared to carnauba jelly. The results of the antioxidant activity by the ABTS method were superior in the mixed jelly, presenting statistical difference of the other jellies. Mixed jelly generally showed good sensory acceptability, where hedonic terms ranged from '' liked slightly '' to '' liked '' and intent to purchase ranged from '' perhaps buying / perhaps not buying '' to ' 'would buy' ', which indicates that the product can be used for marketing. Thus, it can be concluded that even with the thermal processing for the preparation of the jelly, the total phenolic compounds and the antioxidant capacity in the mixed jelly were higher than in the carnauba and grape jellies separately.